Commit message: bpf: Verifer, adjust_scalar_min_max_vals to always call update_reg_bounds()

Currently, for all op verification we call __red_deduce_bounds() and
__red_bound_offset() but we only call __update_reg_bounds() in bitwise
ops. However, we could benefit from calling __update_reg_bounds() in
BPF_ADD, BPF_SUB, and BPF_MUL cases as well.

For example, a register with state 'R1_w=invP0' when we subtract from
it,

 w1 -= 2

Before coerce we will now have an smin_value=S64_MIN, smax_value=U64_MAX
and unsigned bounds umin_value=0, umax_value=U64_MAX. These will then
be clamped to S32_MIN, U32_MAX values by coerce in the case of alu32 op
as done in above example. However tnum will be a constant because the
ALU op is done on a constant.

Without update_reg_bounds() we have a scenario where tnum is a const
but our unsigned bounds do not reflect this. By calling update_reg_bounds
after coerce to 32bit we further refine the umin_value to U64_MAX in the
alu64 case or U32_MAX in the alu32 case above.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/158507151689.15666.566796274289413203.stgit@john-Precision-5820-Tower
CVE: None
Vulnerability description: None

Project: linux
File: verifier.c

static int realloc_func_state(struct bpf_func_state *state, int stack_size,
			      int refs_size, bool copy_old)
{
	int err = realloc_reference_state(state, refs_size, copy_old);
	if (err)
		return err;
	return realloc_stack_state(state, stack_size, copy_old);
}

Project: linux
File: verifier.c

static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
{
	const struct bpf_reg_state *reg = reg_state(env, regno);

	return type_is_pkt_pointer(reg->type);
}

Project: linux
File: verifier.c

static bool type_is_pkt_pointer(enum bpf_reg_type type)
{
	return type == PTR_TO_PACKET ||
	       type == PTR_TO_PACKET_META;
}

Project: linux
File: verifier.c

static bool check_ids(u32 old_id, u32 cur_id, struct idpair *idmap)
{
	unsigned int i;

	for (i = 0; i < ID_MAP_SIZE; i++) {
		if (!idmap[i].old) {
			/* Reached an empty slot; haven't seen this id before */
			idmap[i].old = old_id;
			idmap[i].cur = cur_id;
			return true;
		}
		if (idmap[i].old == old_id)
			return idmap[i].cur == cur_id;
	}
	/* We ran out of idmap slots, which should be impossible */
	WARN_ON_ONCE(1);
	return false;
}

Project: linux
File: verifier.c

static int copy_func_state(struct bpf_func_state *dst,
			   const struct bpf_func_state *src)
{
	int err;

	err = realloc_func_state(dst, src->allocated_stack, src->acquired_refs,
				 false);
	if (err)
		return err;
	memcpy(dst, src, offsetof(struct bpf_func_state, acquired_refs));
	err = copy_reference_state(dst, src);
	if (err)
		return err;
	return copy_stack_state(dst, src);
}

Project: linux
File: verifier.c

static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno)
{
	const struct bpf_reg_state *reg = reg_state(env, regno);

	/* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */
	return reg->type == PTR_TO_FLOW_KEYS;
}

Project: linux
File: verifier.c

static int mark_chain_precision(struct bpf_verifier_env *env, int regno)
{
	return __mark_chain_precision(env, regno, -1);
}

Project: linux
File: verifier.c

static bool signed_sub_overflows(s64 a, s64 b)
{
	/* Do the sub in u64, where overflow is well-defined */
	s64 res = (s64)((u64)a - (u64)b);

	if (b < 0)
		return res < a;
	return res > a;
}

Project: linux
File: verifier.c

static int check_cfg(struct bpf_verifier_env *env)
{
	struct bpf_insn *insns = env->prog->insnsi;
	int insn_cnt = env->prog->len;
	int *insn_stack, *insn_state;
	int ret = 0;
	int i, t;

	insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
	if (!insn_state)
		return -ENOMEM;

	insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
	if (!insn_stack) {
		kvfree(insn_state);
		return -ENOMEM;
	}

	insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */
	insn_stack[0] = 0; /* 0 is the first instruction */
	env->cfg.cur_stack = 1;

peek_stack:
	if (env->cfg.cur_stack == 0)
		goto check_state;
	t = insn_stack[env->cfg.cur_stack - 1];

	if (BPF_CLASS(insns[t].code) == BPF_JMP ||
	    BPF_CLASS(insns[t].code) == BPF_JMP32) {
		u8 opcode = BPF_OP(insns[t].code);

		if (opcode == BPF_EXIT) {
			goto mark_explored;
		} else if (opcode == BPF_CALL) {
			ret = push_insn(t, t + 1, FALLTHROUGH, env, false);
			if (ret == 1)
				goto peek_stack;
			else if (ret < 0)
				goto err_free;
			if (t + 1 < insn_cnt)
				init_explored_state(env, t + 1);
			if (insns[t].src_reg == BPF_PSEUDO_CALL) {
				init_explored_state(env, t);
				ret = push_insn(t, t + insns[t].imm + 1, BRANCH,
						env, false);
				if (ret == 1)
					goto peek_stack;
				else if (ret < 0)
					goto err_free;
			}
		} else if (opcode == BPF_JA) {
			if (BPF_SRC(insns[t].code) != BPF_K) {
				ret = -EINVAL;
				goto err_free;
			}
			/* unconditional jump with single edge */
			ret = push_insn(t, t + insns[t].off + 1,
					FALLTHROUGH, env, true);
			if (ret == 1)
				goto peek_stack;
			else if (ret < 0)
				goto err_free;
			/* unconditional jmp is not a good pruning point,
			 * but it's marked, since backtracking needs
			 * to record jmp history in is_state_visited().
			 */
			init_explored_state(env, t + insns[t].off + 1);
			/* tell verifier to check for equivalent states
			 * after every call and jump
			 */
			if (t + 1 < insn_cnt)
				init_explored_state(env, t + 1);
		} else {
			/* conditional jump with two edges */
			init_explored_state(env, t);
			ret = push_insn(t, t + 1, FALLTHROUGH, env, true);
			if (ret == 1)
				goto peek_stack;
			else if (ret < 0)
				goto err_free;

			ret = push_insn(t, t + insns[t].off + 1, BRANCH, env, true);
			if (ret == 1)
				goto peek_stack;
			else if (ret < 0)
				goto err_free;
		}
	} else {
		/* all other non-branch instructions with single
		 * fall-through edge
		 */
		ret = push_insn(t, t + 1, FALLTHROUGH, env, false);
		if (ret == 1)
			goto peek_stack;
		else if (ret < 0)
			goto err_free;
	}

mark_explored:
	insn_state[t] = EXPLORED;
	if (env->cfg.cur_stack-- <= 0) {
		verbose(env, "pop stack internal bug\n");
		ret = -EFAULT;
		goto err_free;
	}
	goto peek_stack;

check_state:
	for (i = 0; i < insn_cnt; i++) {
		if (insn_state[i] != EXPLORED) {
			verbose(env, "unreachable insn %d\n", i);
			ret = -EINVAL;
			goto err_free;
		}
	}
	ret = 0; /* cfg looks good */

err_free:
	kvfree(insn_state);
	kvfree(insn_stack);
	env->cfg.insn_state = env->cfg.insn_stack = NULL;
	return ret;
}

Project: linux
File: verifier.c

static bool may_access_skb(enum bpf_prog_type type)
{
	switch (type) {
	case BPF_PROG_TYPE_SOCKET_FILTER:
	case BPF_PROG_TYPE_SCHED_CLS:
	case BPF_PROG_TYPE_SCHED_ACT:
		return true;
	default:
		return false;
	}
}

Project: linux
File: verifier.c

static int fixup_bpf_calls(struct bpf_verifier_env *env)
{
	struct bpf_prog *prog = env->prog;
	bool expect_blinding = bpf_jit_blinding_enabled(prog);
	struct bpf_insn *insn = prog->insnsi;
	const struct bpf_func_proto *fn;
	const int insn_cnt = prog->len;
	const struct bpf_map_ops *ops;
	struct bpf_insn_aux_data *aux;
	struct bpf_insn insn_buf[16];
	struct bpf_prog *new_prog;
	struct bpf_map *map_ptr;
	int i, ret, cnt, delta = 0;

	for (i = 0; i < insn_cnt; i++, insn++) {
		if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) ||
		    insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) ||
		    insn->code == (BPF_ALU | BPF_MOD | BPF_X) ||
		    insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
			bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
			struct bpf_insn mask_and_div[] = {
				BPF_MOV32_REG(insn->src_reg, insn->src_reg),
				/* Rx div 0 -> 0 */
				BPF_JMP_IMM(BPF_JNE, insn->src_reg, 0, 2),
				BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg),
				BPF_JMP_IMM(BPF_JA, 0, 0, 1),
				*insn,
			};
			struct bpf_insn mask_and_mod[] = {
				BPF_MOV32_REG(insn->src_reg, insn->src_reg),
				/* Rx mod 0 -> Rx */
				BPF_JMP_IMM(BPF_JEQ, insn->src_reg, 0, 1),
				*insn,
			};
			struct bpf_insn *patchlet;

			if (insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) ||
			    insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
				patchlet = mask_and_div + (is64 ? 1 : 0);
				cnt = ARRAY_SIZE(mask_and_div) - (is64 ? 1 : 0);
			} else {
				patchlet = mask_and_mod + (is64 ? 1 : 0);
				cnt = ARRAY_SIZE(mask_and_mod) - (is64 ? 1 : 0);
			}

			new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt);
			if (!new_prog)
				return -ENOMEM;

			delta    += cnt - 1;
			env->prog = prog = new_prog;
			insn      = new_prog->insnsi + i + delta;
			continue;
		}

		if (BPF_CLASS(insn->code) == BPF_LD &&
		    (BPF_MODE(insn->code) == BPF_ABS ||
		     BPF_MODE(insn->code) == BPF_IND)) {
			cnt = env->ops->gen_ld_abs(insn, insn_buf);
			if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
				verbose(env, "bpf verifier is misconfigured\n");
				return -EINVAL;
			}

			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
			if (!new_prog)
				return -ENOMEM;

			delta    += cnt - 1;
			env->prog = prog = new_prog;
			insn      = new_prog->insnsi + i + delta;
			continue;
		}

		if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) ||
		    insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) {
			const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X;
			const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X;
			struct bpf_insn insn_buf[16];
			struct bpf_insn *patch = &insn_buf[0];
			bool issrc, isneg;
			u32 off_reg;

			aux = &env->insn_aux_data[i + delta];
			if (!aux->alu_state ||
			    aux->alu_state == BPF_ALU_NON_POINTER)
				continue;

			isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
			issrc = (aux->alu_state & BPF_ALU_SANITIZE) ==
				BPF_ALU_SANITIZE_SRC;

			off_reg = issrc ? insn->src_reg : insn->dst_reg;
			if (isneg)
				*patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
			*patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit - 1);
			*patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
			*patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
			*patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
			*patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
			if (issrc) {
				*patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX,
							 off_reg);
				insn->src_reg = BPF_REG_AX;
			} else {
				*patch++ = BPF_ALU64_REG(BPF_AND, off_reg,
							 BPF_REG_AX);
			}
			if (isneg)
				insn->code = insn->code == code_add ?
					     code_sub : code_add;
			*patch++ = *insn;
			if (issrc && isneg)
				*patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
			cnt = patch - insn_buf;

			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
			if (!new_prog)
				return -ENOMEM;

			delta    += cnt - 1;
			env->prog = prog = new_prog;
			insn      = new_prog->insnsi + i + delta;
			continue;
		}

		if (insn->code != (BPF_JMP | BPF_CALL))
			continue;
		if (insn->src_reg == BPF_PSEUDO_CALL)
			continue;

		if (insn->imm == BPF_FUNC_get_route_realm)
			prog->dst_needed = 1;
		if (insn->imm == BPF_FUNC_get_prandom_u32)
			bpf_user_rnd_init_once();
		if (insn->imm == BPF_FUNC_override_return)
			prog->kprobe_override = 1;
		if (insn->imm == BPF_FUNC_tail_call) {
			/* If we tail call into other programs, we
			 * cannot make any assumptions since they can
			 * be replaced dynamically during runtime in
			 * the program array.
			 */
			prog->cb_access = 1;
			env->prog->aux->stack_depth = MAX_BPF_STACK;
			env->prog->aux->max_pkt_offset = MAX_PACKET_OFF;

			/* mark bpf_tail_call as different opcode to avoid
			 * conditional branch in the interpeter for every normal
			 * call and to prevent accidental JITing by JIT compiler
			 * that doesn't support bpf_tail_call yet
			 */
			insn->imm = 0;
			insn->code = BPF_JMP | BPF_TAIL_CALL;

			aux = &env->insn_aux_data[i + delta];
			if (env->allow_ptr_leaks && !expect_blinding &&
			    prog->jit_requested &&
			    !bpf_map_key_poisoned(aux) &&
			    !bpf_map_ptr_poisoned(aux) &&
			    !bpf_map_ptr_unpriv(aux)) {
				struct bpf_jit_poke_descriptor desc = {
					.reason = BPF_POKE_REASON_TAIL_CALL,
					.tail_call.map = BPF_MAP_PTR(aux->map_ptr_state),
					.tail_call.key = bpf_map_key_immediate(aux),
				};

				ret = bpf_jit_add_poke_descriptor(prog, &desc);
				if (ret < 0) {
					verbose(env, "adding tail call poke descriptor failed\n");
					return ret;
				}

				insn->imm = ret + 1;
				continue;
			}

			if (!bpf_map_ptr_unpriv(aux))
				continue;

			/* instead of changing every JIT dealing with tail_call
			 * emit two extra insns:
			 * if (index >= max_entries) goto out;
			 * index &= array->index_mask;
			 * to avoid out-of-bounds cpu speculation
			 */
			if (bpf_map_ptr_poisoned(aux)) {
				verbose(env, "tail_call abusing map_ptr\n");
				return -EINVAL;
			}

			map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
			insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3,
						  map_ptr->max_entries, 2);
			insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3,
						    container_of(map_ptr,
								 struct bpf_array,
								 map)->index_mask);
			insn_buf[2] = *insn;
			cnt = 3;
			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
			if (!new_prog)
				return -ENOMEM;

			delta    += cnt - 1;
			env->prog = prog = new_prog;
			insn      = new_prog->insnsi + i + delta;
			continue;
		}

		/* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup
		 * and other inlining handlers are currently limited to 64 bit
		 * only.
		 */
		if (prog->jit_requested && BITS_PER_LONG == 64 &&
		    (insn->imm == BPF_FUNC_map_lookup_elem ||
		     insn->imm == BPF_FUNC_map_update_elem ||
		     insn->imm == BPF_FUNC_map_delete_elem ||
		     insn->imm == BPF_FUNC_map_push_elem   ||
		     insn->imm == BPF_FUNC_map_pop_elem    ||
		     insn->imm == BPF_FUNC_map_peek_elem)) {
			aux = &env->insn_aux_data[i + delta];
			if (bpf_map_ptr_poisoned(aux))
				goto patch_call_imm;

			map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
			ops = map_ptr->ops;
			if (insn->imm == BPF_FUNC_map_lookup_elem &&
			    ops->map_gen_lookup) {
				cnt = ops->map_gen_lookup(map_ptr, insn_buf);
				if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
					verbose(env, "bpf verifier is misconfigured\n");
					return -EINVAL;
				}

				new_prog = bpf_patch_insn_data(env, i + delta,
							       insn_buf, cnt);
				if (!new_prog)
					return -ENOMEM;

				delta    += cnt - 1;
				env->prog = prog = new_prog;
				insn      = new_prog->insnsi + i + delta;
				continue;
			}

			BUILD_BUG_ON(!__same_type(ops->map_lookup_elem,
				     (void *(*)(struct bpf_map *map, void *key))NULL));
			BUILD_BUG_ON(!__same_type(ops->map_delete_elem,
				     (int (*)(struct bpf_map *map, void *key))NULL));
			BUILD_BUG_ON(!__same_type(ops->map_update_elem,
				     (int (*)(struct bpf_map *map, void *key, void *value,
					      u64 flags))NULL));
			BUILD_BUG_ON(!__same_type(ops->map_push_elem,
				     (int (*)(struct bpf_map *map, void *value,
					      u64 flags))NULL));
			BUILD_BUG_ON(!__same_type(ops->map_pop_elem,
				     (int (*)(struct bpf_map *map, void *value))NULL));
			BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
				     (int (*)(struct bpf_map *map, void *value))NULL));

			switch (insn->imm) {
			case BPF_FUNC_map_lookup_elem:
				insn->imm = BPF_CAST_CALL(ops->map_lookup_elem) -
					    __bpf_call_base;
				continue;
			case BPF_FUNC_map_update_elem:
				insn->imm = BPF_CAST_CALL(ops->map_update_elem) -
					    __bpf_call_base;
				continue;
			case BPF_FUNC_map_delete_elem:
				insn->imm = BPF_CAST_CALL(ops->map_delete_elem) -
					    __bpf_call_base;
				continue;
			case BPF_FUNC_map_push_elem:
				insn->imm = BPF_CAST_CALL(ops->map_push_elem) -
					    __bpf_call_base;
				continue;
			case BPF_FUNC_map_pop_elem:
				insn->imm = BPF_CAST_CALL(ops->map_pop_elem) -
					    __bpf_call_base;
				continue;
			case BPF_FUNC_map_peek_elem:
				insn->imm = BPF_CAST_CALL(ops->map_peek_elem) -
					    __bpf_call_base;
				continue;
			}

			goto patch_call_imm;
		}

		if (prog->jit_requested && BITS_PER_LONG == 64 &&
		    insn->imm == BPF_FUNC_jiffies64) {
			struct bpf_insn ld_jiffies_addr[2] = {
				BPF_LD_IMM64(BPF_REG_0,
					     (unsigned long)&jiffies),
			};

			insn_buf[0] = ld_jiffies_addr[0];
			insn_buf[1] = ld_jiffies_addr[1];
			insn_buf[2] = BPF_LDX_MEM(BPF_DW, BPF_REG_0,
						  BPF_REG_0, 0);
			cnt = 3;

			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf,
						       cnt);
			if (!new_prog)
				return -ENOMEM;

			delta    += cnt - 1;
			env->prog = prog = new_prog;
			insn      = new_prog->insnsi + i + delta;
			continue;
		}

patch_call_imm:
		fn = env->ops->get_func_proto(insn->imm, env->prog);
		/* all functions that have prototype and verifier allowed
		 * programs to call them, must be real in-kernel functions
		 */
		if (!fn->func) {
			verbose(env,
				"kernel subsystem misconfigured func %s#%d\n",
				func_id_name(insn->imm), insn->imm);
			return -EFAULT;
		}
		insn->imm = fn->func - __bpf_call_base;
	}

	/* Since poke tab is now finalized, publish aux to tracker. */
	for (i = 0; i < prog->aux->size_poke_tab; i++) {
		map_ptr = prog->aux->poke_tab[i].tail_call.map;
		if (!map_ptr->ops->map_poke_track ||
		    !map_ptr->ops->map_poke_untrack ||
		    !map_ptr->ops->map_poke_run) {
			verbose(env, "bpf verifier is misconfigured\n");
			return -EINVAL;
		}

		ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux);
		if (ret < 0) {
			verbose(env, "tracking tail call prog failed\n");
			return ret;
		}
	}

	return 0;
}

Project: linux
File: verifier.c

static bool register_is_const(struct bpf_reg_state *reg)
{
	return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off);
}

Project: linux
File: verifier.c

static int check_btf_func(struct bpf_verifier_env *env,
			  const union bpf_attr *attr,
			  union bpf_attr __user *uattr)
{
	u32 i, nfuncs, urec_size, min_size;
	u32 krec_size = sizeof(struct bpf_func_info);
	struct bpf_func_info *krecord;
	struct bpf_func_info_aux *info_aux = NULL;
	const struct btf_type *type;
	struct bpf_prog *prog;
	const struct btf *btf;
	void __user *urecord;
	u32 prev_offset = 0;
	int ret = 0;

	nfuncs = attr->func_info_cnt;
	if (!nfuncs)
		return 0;

	if (nfuncs != env->subprog_cnt) {
		verbose(env, "number of funcs in func_info doesn't match number of subprogs\n");
		return -EINVAL;
	}

	urec_size = attr->func_info_rec_size;
	if (urec_size < MIN_BPF_FUNCINFO_SIZE ||
	    urec_size > MAX_FUNCINFO_REC_SIZE ||
	    urec_size % sizeof(u32)) {
		verbose(env, "invalid func info rec size %u\n", urec_size);
		return -EINVAL;
	}

	prog = env->prog;
	btf = prog->aux->btf;

	urecord = u64_to_user_ptr(attr->func_info);
	min_size = min_t(u32, krec_size, urec_size);

	krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN);
	if (!krecord)
		return -ENOMEM;
	info_aux = kcalloc(nfuncs, sizeof(*info_aux), GFP_KERNEL | __GFP_NOWARN);
	if (!info_aux)
		goto err_free;

	for (i = 0; i < nfuncs; i++) {
		ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size);
		if (ret) {
			if (ret == -E2BIG) {
				verbose(env, "nonzero tailing record in func info");
				/* set the size kernel expects so loader can zero
				 * out the rest of the record.
				 */
				if (put_user(min_size, &uattr->func_info_rec_size))
					ret = -EFAULT;
			}
			goto err_free;
		}

		if (copy_from_user(&krecord[i], urecord, min_size)) {
			ret = -EFAULT;
			goto err_free;
		}

		/* check insn_off */
		if (i == 0) {
			if (krecord[i].insn_off) {
				verbose(env,
					"nonzero insn_off %u for the first func info record",
					krecord[i].insn_off);
				ret = -EINVAL;
				goto err_free;
			}
		} else if (krecord[i].insn_off <= prev_offset) {
			verbose(env,
				"same or smaller insn offset (%u) than previous func info record (%u)",
				krecord[i].insn_off, prev_offset);
			ret = -EINVAL;
			goto err_free;
		}

		if (env->subprog_info[i].start != krecord[i].insn_off) {
			verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n");
			ret = -EINVAL;
			goto err_free;
		}

		/* check type_id */
		type = btf_type_by_id(btf, krecord[i].type_id);
		if (!type || !btf_type_is_func(type)) {
			verbose(env, "invalid type id %d in func info",
				krecord[i].type_id);
			ret = -EINVAL;
			goto err_free;
		}
		info_aux[i].linkage = BTF_INFO_VLEN(type->info);
		prev_offset = krecord[i].insn_off;
		urecord += urec_size;
	}

	prog->aux->func_info = krecord;
	prog->aux->func_info_cnt = nfuncs;
	prog->aux->func_info_aux = info_aux;
	return 0;

err_free:
	kvfree(krecord);
	kfree(info_aux);
	return ret;
}

Project: linux
File: verifier.c

static bool __is_pointer_value(bool allow_ptr_leaks,
			       const struct bpf_reg_state *reg)
{
	if (allow_ptr_leaks)
		return false;

	return reg->type != SCALAR_VALUE;
}

Project: linux
File: verifier.c

static u64 gen_hi_min(struct tnum var)
{
	return var.value & ~0xffffffffULL;
}

Project: linux
File: verifier.c

static int do_check_main(struct bpf_verifier_env *env)
{
	int ret;

	env->insn_idx = 0;
	ret = do_check_common(env, 0);
	if (!ret)
		env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
	return ret;
}

Project: linux
File: verifier.c

static void release_reg_references(struct bpf_verifier_env *env,
				   struct bpf_func_state *state,
				   int ref_obj_id)
{
	struct bpf_reg_state *regs = state->regs, *reg;
	int i;

	for (i = 0; i < MAX_BPF_REG; i++)
		if (regs[i].ref_obj_id == ref_obj_id)
			mark_reg_unknown(env, regs, i);

	bpf_for_each_spilled_reg(i, state, reg) {
		if (!reg)
			continue;
		if (reg->ref_obj_id == ref_obj_id)
			__mark_reg_unknown(env, reg);
	}
}

Project: linux
File: verifier.c

static void sanitize_insn_aux_data(struct bpf_verifier_env *env)
{
	struct bpf_insn *insn = env->prog->insnsi;
	struct bpf_insn_aux_data *aux;
	int i, class;

	for (i = 0; i < env->prog->len; i++) {
		class = BPF_CLASS(insn[i].code);
		if (class != BPF_LDX && class != BPF_STX)
			continue;
		aux = &env->insn_aux_data[i];
		if (aux->seen != env->pass_cnt)
			continue;
		memset(aux, 0, offsetof(typeof(*aux), orig_idx));
	}
}

Project: linux
File: verifier.c

static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)
{
	const struct bpf_reg_state *reg = reg_state(env, regno);

	return reg->type == PTR_TO_CTX;
}

Project: linux
File: verifier.c

static void __mark_reg_unknown(const struct bpf_verifier_env *env,
			       struct bpf_reg_state *reg)
{
	/*
	 * Clear type, id, off, and union(map_ptr, range) and
	 * padding between 'type' and union
	 */
	memset(reg, 0, offsetof(struct bpf_reg_state, var_off));
	reg->type = SCALAR_VALUE;
	reg->var_off = tnum_unknown;
	reg->frameno = 0;
	reg->precise = env->subprog_cnt > 1 || !env->allow_ptr_leaks ?
		       true : false;
	__mark_reg_unbounded(reg);
}

Project: linux
File: verifier.c

static int check_tp_buffer_access(struct bpf_verifier_env *env,
				  const struct bpf_reg_state *reg,
				  int regno, int off, int size)
{
	if (off < 0) {
		verbose(env,
			"R%d invalid tracepoint buffer access: off=%d, size=%d",
			regno, off, size);
		return -EACCES;
	}
	if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
		char tn_buf[48];

		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
		verbose(env,
			"R%d invalid variable buffer offset: off=%d, var_off=%s",
			regno, off, tn_buf);
		return -EACCES;
	}
	if (off + size > env->prog->aux->max_tp_access)
		env->prog->aux->max_tp_access = off + size;

	return 0;
}

Project: linux
File: verifier.c

static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn)
{
	int err;

	if ((BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) ||
	    insn->imm != 0) {
		verbose(env, "BPF_XADD uses reserved fields\n");
		return -EINVAL;
	}

	/* check src1 operand */
	err = check_reg_arg(env, insn->src_reg, SRC_OP);
	if (err)
		return err;

	/* check src2 operand */
	err = check_reg_arg(env, insn->dst_reg, SRC_OP);
	if (err)
		return err;

	if (is_pointer_value(env, insn->src_reg)) {
		verbose(env, "R%d leaks addr into mem\n", insn->src_reg);
		return -EACCES;
	}

	if (is_ctx_reg(env, insn->dst_reg) ||
	    is_pkt_reg(env, insn->dst_reg) ||
	    is_flow_key_reg(env, insn->dst_reg) ||
	    is_sk_reg(env, insn->dst_reg)) {
		verbose(env, "BPF_XADD stores into R%d %s is not allowed\n",
			insn->dst_reg,
			reg_type_str[reg_state(env, insn->dst_reg)->type]);
		return -EACCES;
	}

	/* check whether atomic_add can read the memory */
	err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
			       BPF_SIZE(insn->code), BPF_READ, -1, true);
	if (err)
		return err;

	/* check whether atomic_add can write into the same memory */
	return check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
				BPF_SIZE(insn->code), BPF_WRITE, -1, true);
}

Project: linux
File: verifier.c

static int check_return_code(struct bpf_verifier_env *env)
{
	struct tnum enforce_attach_type_range = tnum_unknown;
	const struct bpf_prog *prog = env->prog;
	struct bpf_reg_state *reg;
	struct tnum range = tnum_range(0, 1);
	int err;

	/* The struct_ops func-ptr's return type could be "void" */
	if (env->prog->type == BPF_PROG_TYPE_STRUCT_OPS &&
	    !prog->aux->attach_func_proto->type)
		return 0;

	/* eBPF calling convetion is such that R0 is used
	 * to return the value from eBPF program.
	 * Make sure that it's readable at this time
	 * of bpf_exit, which means that program wrote
	 * something into it earlier
	 */
	err = check_reg_arg(env, BPF_REG_0, SRC_OP);
	if (err)
		return err;

	if (is_pointer_value(env, BPF_REG_0)) {
		verbose(env, "R0 leaks addr as return value\n");
		return -EACCES;
	}

	switch (env->prog->type) {
	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
		if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG ||
		    env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG)
			range = tnum_range(1, 1);
		break;
	case BPF_PROG_TYPE_CGROUP_SKB:
		if (env->prog->expected_attach_type == BPF_CGROUP_INET_EGRESS) {
			range = tnum_range(0, 3);
			enforce_attach_type_range = tnum_range(2, 3);
		}
		break;
	case BPF_PROG_TYPE_CGROUP_SOCK:
	case BPF_PROG_TYPE_SOCK_OPS:
	case BPF_PROG_TYPE_CGROUP_DEVICE:
	case BPF_PROG_TYPE_CGROUP_SYSCTL:
	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
		break;
	case BPF_PROG_TYPE_RAW_TRACEPOINT:
		if (!env->prog->aux->attach_btf_id)
			return 0;
		range = tnum_const(0);
		break;
	default:
		return 0;
	}

	reg = cur_regs(env) + BPF_REG_0;
	if (reg->type != SCALAR_VALUE) {
		verbose(env, "At program exit the register R0 is not a known value (%s)\n",
			reg_type_str[reg->type]);
		return -EINVAL;
	}

	if (!tnum_in(range, reg->var_off)) {
		char tn_buf[48];

		verbose(env, "At program exit the register R0 ");
		if (!tnum_is_unknown(reg->var_off)) {
			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
			verbose(env, "has value %s", tn_buf);
		} else {
			verbose(env, "has unknown scalar value");
		}
		tnum_strn(tn_buf, sizeof(tn_buf), range);
		verbose(env, " should have been in %s\n", tn_buf);
		return -EINVAL;
	}

	if (!tnum_is_unknown(enforce_attach_type_range) &&
	    tnum_in(enforce_attach_type_range, reg->var_off))
		env->prog->enforce_expected_attach_type = 1;
	return 0;
}

Project: linux
File: verifier.c

static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux)
{
	return BPF_MAP_PTR(aux->map_ptr_state) == BPF_MAP_PTR_POISON;
}

Project: linux
File: verifier.c

static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len)
{
	int i;

	if (len == 1)
		return;
	/* NOTE: fake 'exit' subprog should be updated as well. */
	for (i = 0; i <= env->subprog_cnt; i++) {
		if (env->subprog_info[i].start <= off)
			continue;
		env->subprog_info[i].start += len - 1;
	}
}

Project: linux
File: verifier.c

static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
				   const struct bpf_reg_state *reg,
				   int off, int size, bool strict)
{
	struct tnum reg_off;
	int ip_align;

	/* Byte size accesses are always allowed. */
	if (!strict || size == 1)
		return 0;

	/* For platforms that do not have a Kconfig enabling
	 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of
	 * NET_IP_ALIGN is universally set to '2'.  And on platforms
	 * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get
	 * to this code only in strict mode where we want to emulate
	 * the NET_IP_ALIGN==2 checking.  Therefore use an
	 * unconditional IP align value of '2'.
	 */
	ip_align = 2;

	reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off));
	if (!tnum_is_aligned(reg_off, size)) {
		char tn_buf[48];

		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
		verbose(env,
			"misaligned packet access off %d+%s+%d+%d size %d\n",
			ip_align, tn_buf, reg->off, off, size);
		return -EACCES;
	}

	return 0;
}

Project: linux
File: verifier.c

static void bpf_map_key_store(struct bpf_insn_aux_data *aux, u64 state)
{
	bool poisoned = bpf_map_key_poisoned(aux);

	aux->map_key_state = state | BPF_MAP_KEY_SEEN |
			     (poisoned ? BPF_MAP_KEY_POISON : 0ULL);
}

Project: linux
File: verifier.c

static const char *ltrim(const char *s)
{
	while (isspace(*s))
		s++;

	return s;
}

Project: linux
File: verifier.c

static bool is_release_function(enum bpf_func_id func_id)
{
	return func_id == BPF_FUNC_sk_release;
}

Project: linux
File: verifier.c

static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg)
{
	return reg_is_pkt_pointer(reg) ||
	       reg->type == PTR_TO_PACKET_END;
}

Project: linux
File: verifier.c

record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
		int func_id, int insn_idx)
{
	struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
	struct bpf_reg_state *regs = cur_regs(env), *reg;
	struct bpf_map *map = meta->map_ptr;
	struct tnum range;
	u64 val;
	int err;

	if (func_id != BPF_FUNC_tail_call)
		return 0;
	if (!map || map->map_type != BPF_MAP_TYPE_PROG_ARRAY) {
		verbose(env, "kernel subsystem misconfigured verifier\n");
		return -EINVAL;
	}

	range = tnum_range(0, map->max_entries - 1);
	reg = &regs[BPF_REG_3];

	if (!register_is_const(reg) || !tnum_in(range, reg->var_off)) {
		bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
		return 0;
	}

	err = mark_chain_precision(env, BPF_REG_3);
	if (err)
		return err;

	val = reg->var_off.value;
	if (bpf_map_key_unseen(aux))
		bpf_map_key_store(aux, val);
	else if (!bpf_map_key_poisoned(aux) &&
		  bpf_map_key_immediate(aux) != val)
		bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
	return 0;
}

Project: linux
File: verifier.c

static void __reg_combine_min_max(struct bpf_reg_state *src_reg,
				  struct bpf_reg_state *dst_reg)
{
	src_reg->umin_value = dst_reg->umin_value = max(src_reg->umin_value,
							dst_reg->umin_value);
	src_reg->umax_value = dst_reg->umax_value = min(src_reg->umax_value,
							dst_reg->umax_value);
	src_reg->smin_value = dst_reg->smin_value = max(src_reg->smin_value,
							dst_reg->smin_value);
	src_reg->smax_value = dst_reg->smax_value = min(src_reg->smax_value,
							dst_reg->smax_value);
	src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off,
							     dst_reg->var_off);
	/* We might have learned new bounds from the var_off. */
	__update_reg_bounds(src_reg);
	__update_reg_bounds(dst_reg);
	/* We might have learned something about the sign bit. */
	__reg_deduce_bounds(src_reg);
	__reg_deduce_bounds(dst_reg);
	/* We might have learned some bits from the bounds. */
	__reg_bound_offset(src_reg);
	__reg_bound_offset(dst_reg);
	/* Intersecting with the old var_off might have improved our bounds
	 * slightly.  e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
	 * then new var_off is (0; 0x7f...fc) which improves our umax.
	 */
	__update_reg_bounds(src_reg);
	__update_reg_bounds(dst_reg);
}

Project: linux
File: verifier.c

static bool reg_type_mismatch_ok(enum bpf_reg_type type)
{
	switch (type) {
	case PTR_TO_CTX:
	case PTR_TO_SOCKET:
	case PTR_TO_SOCKET_OR_NULL:
	case PTR_TO_SOCK_COMMON:
	case PTR_TO_SOCK_COMMON_OR_NULL:
	case PTR_TO_TCP_SOCK:
	case PTR_TO_TCP_SOCK_OR_NULL:
	case PTR_TO_XDP_SOCK:
	case PTR_TO_BTF_ID:
		return false;
	default:
		return true;
	}
}

Project: linux
File: verifier.c

static bool arg_type_may_be_refcounted(enum bpf_arg_type type)
{
	return type == ARG_PTR_TO_SOCK_COMMON;
}

Project: linux
File: verifier.c

static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env)
{
	struct bpf_insn *insn = env->prog->insnsi;
	int insn_cnt = env->prog->len;
	int i;

	for (i = 0; i < insn_cnt; i++, insn++)
		if (insn->code == (BPF_LD | BPF_IMM | BPF_DW))
			insn->src_reg = 0;
}

Project: linux
File: verifier.c

int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
	      union bpf_attr __user *uattr)
{
	u64 start_time = ktime_get_ns();
	struct bpf_verifier_env *env;
	struct bpf_verifier_log *log;
	int i, len, ret = -EINVAL;
	bool is_priv;

	/* no program is valid */
	if (ARRAY_SIZE(bpf_verifier_ops) == 0)
		return -EINVAL;

	/* 'struct bpf_verifier_env' can be global, but since it's not small,
	 * allocate/free it every time bpf_check() is called
	 */
	env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
	if (!env)
		return -ENOMEM;
	log = &env->log;

	len = (*prog)->len;
	env->insn_aux_data =
		vzalloc(array_size(sizeof(struct bpf_insn_aux_data), len));
	ret = -ENOMEM;
	if (!env->insn_aux_data)
		goto err_free_env;
	for (i = 0; i < len; i++)
		env->insn_aux_data[i].orig_idx = i;
	env->prog = *prog;
	env->ops = bpf_verifier_ops[env->prog->type];
	is_priv = capable(CAP_SYS_ADMIN);

	if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
		mutex_lock(&bpf_verifier_lock);
		if (!btf_vmlinux)
			btf_vmlinux = btf_parse_vmlinux();
		mutex_unlock(&bpf_verifier_lock);
	}

	/* grab the mutex to protect few globals used by verifier */
	if (!is_priv)
		mutex_lock(&bpf_verifier_lock);

	if (attr->log_level || attr->log_buf || attr->log_size) {
		/* user requested verbose verifier output
		 * and supplied buffer to store the verification trace
		 */
		log->level = attr->log_level;
		log->ubuf = (char __user *) (unsigned long) attr->log_buf;
		log->len_total = attr->log_size;

		ret = -EINVAL;
		/* log attributes have to be sane */
		if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 ||
		    !log->level || !log->ubuf || log->level & ~BPF_LOG_MASK)
			goto err_unlock;
	}

	if (IS_ERR(btf_vmlinux)) {
		/* Either gcc or pahole or kernel are broken. */
		verbose(env, "in-kernel BTF is malformed\n");
		ret = PTR_ERR(btf_vmlinux);
		goto skip_full_check;
	}

	env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT);
	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
		env->strict_alignment = true;
	if (attr->prog_flags & BPF_F_ANY_ALIGNMENT)
		env->strict_alignment = false;

	env->allow_ptr_leaks = is_priv;

	if (is_priv)
		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;

	ret = replace_map_fd_with_map_ptr(env);
	if (ret < 0)
		goto skip_full_check;

	if (bpf_prog_is_dev_bound(env->prog->aux)) {
		ret = bpf_prog_offload_verifier_prep(env->prog);
		if (ret)
			goto skip_full_check;
	}

	env->explored_states = kvcalloc(state_htab_size(env),
				       sizeof(struct bpf_verifier_state_list *),
				       GFP_USER);
	ret = -ENOMEM;
	if (!env->explored_states)
		goto skip_full_check;

	ret = check_subprogs(env);
	if (ret < 0)
		goto skip_full_check;

	ret = check_btf_info(env, attr, uattr);
	if (ret < 0)
		goto skip_full_check;

	ret = check_attach_btf_id(env);
	if (ret)
		goto skip_full_check;

	ret = check_cfg(env);
	if (ret < 0)
		goto skip_full_check;

	ret = do_check_subprogs(env);
	ret = ret ?: do_check_main(env);

	if (ret == 0 && bpf_prog_is_dev_bound(env->prog->aux))
		ret = bpf_prog_offload_finalize(env);

skip_full_check:
	kvfree(env->explored_states);

	if (ret == 0)
		ret = check_max_stack_depth(env);

	/* instruction rewrites happen after this point */
	if (is_priv) {
		if (ret == 0)
			opt_hard_wire_dead_code_branches(env);
		if (ret == 0)
			ret = opt_remove_dead_code(env);
		if (ret == 0)
			ret = opt_remove_nops(env);
	} else {
		if (ret == 0)
			sanitize_dead_code(env);
	}

	if (ret == 0)
		/* program is valid, convert *(u32*)(ctx + off) accesses */
		ret = convert_ctx_accesses(env);

	if (ret == 0)
		ret = fixup_bpf_calls(env);

	/* do 32-bit optimization after insn patching has done so those patched
	 * insns could be handled correctly.
	 */
	if (ret == 0 && !bpf_prog_is_dev_bound(env->prog->aux)) {
		ret = opt_subreg_zext_lo32_rnd_hi32(env, attr);
		env->prog->aux->verifier_zext = bpf_jit_needs_zext() ? !ret
								     : false;
	}

	if (ret == 0)
		ret = fixup_call_args(env);

	env->verification_time = ktime_get_ns() - start_time;
	print_verification_stats(env);

	if (log->level && bpf_verifier_log_full(log))
		ret = -ENOSPC;
	if (log->level && !log->ubuf) {
		ret = -EFAULT;
		goto err_release_maps;
	}

	if (ret == 0 && env->used_map_cnt) {
		/* if program passed verifier, update used_maps in bpf_prog_info */
		env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt,
							  sizeof(env->used_maps[0]),
							  GFP_KERNEL);

		if (!env->prog->aux->used_maps) {
			ret = -ENOMEM;
			goto err_release_maps;
		}

		memcpy(env->prog->aux->used_maps, env->used_maps,
		       sizeof(env->used_maps[0]) * env->used_map_cnt);
		env->prog->aux->used_map_cnt = env->used_map_cnt;

		/* program is valid. Convert pseudo bpf_ld_imm64 into generic
		 * bpf_ld_imm64 instructions
		 */
		convert_pseudo_ld_imm64(env);
	}

	if (ret == 0)
		adjust_btf_func(env);

err_release_maps:
	if (!env->prog->aux->used_maps)
		/* if we didn't copy map pointers into bpf_prog_info, release
		 * them now. Otherwise free_used_maps() will release them.
		 */
		release_maps(env);
	*prog = env->prog;
err_unlock:
	if (!is_priv)
		mutex_unlock(&bpf_verifier_lock);
	vfree(env->insn_aux_data);
err_free_env:
	kfree(env);
	return ret;
}

Project: linux
File: verifier.c

static bool insn_has_def32(struct bpf_verifier_env *env, struct bpf_insn *insn)
{
	if (insn_no_def(insn))
		return false;

	return !is_reg64(env, insn, insn->dst_reg, NULL, DST_OP);
}

Project: linux
File: verifier.c

static int check_btf_line(struct bpf_verifier_env *env,
			  const union bpf_attr *attr,
			  union bpf_attr __user *uattr)
{
	u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0;
	struct bpf_subprog_info *sub;
	struct bpf_line_info *linfo;
	struct bpf_prog *prog;
	const struct btf *btf;
	void __user *ulinfo;
	int err;

	nr_linfo = attr->line_info_cnt;
	if (!nr_linfo)
		return 0;

	rec_size = attr->line_info_rec_size;
	if (rec_size < MIN_BPF_LINEINFO_SIZE ||
	    rec_size > MAX_LINEINFO_REC_SIZE ||
	    rec_size & (sizeof(u32) - 1))
		return -EINVAL;

	/* Need to zero it in case the userspace may
	 * pass in a smaller bpf_line_info object.
	 */
	linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info),
			 GFP_KERNEL | __GFP_NOWARN);
	if (!linfo)
		return -ENOMEM;

	prog = env->prog;
	btf = prog->aux->btf;

	s = 0;
	sub = env->subprog_info;
	ulinfo = u64_to_user_ptr(attr->line_info);
	expected_size = sizeof(struct bpf_line_info);
	ncopy = min_t(u32, expected_size, rec_size);
	for (i = 0; i < nr_linfo; i++) {
		err = bpf_check_uarg_tail_zero(ulinfo, expected_size, rec_size);
		if (err) {
			if (err == -E2BIG) {
				verbose(env, "nonzero tailing record in line_info");
				if (put_user(expected_size,
					     &uattr->line_info_rec_size))
					err = -EFAULT;
			}
			goto err_free;
		}

		if (copy_from_user(&linfo[i], ulinfo, ncopy)) {
			err = -EFAULT;
			goto err_free;
		}

		/*
		 * Check insn_off to ensure
		 * 1) strictly increasing AND
		 * 2) bounded by prog->len
		 *
		 * The linfo[0].insn_off == 0 check logically falls into
		 * the later "missing bpf_line_info for func..." case
		 * because the first linfo[0].insn_off must be the
		 * first sub also and the first sub must have
		 * subprog_info[0].start == 0.
		 */
		if ((i && linfo[i].insn_off <= prev_offset) ||
		    linfo[i].insn_off >= prog->len) {
			verbose(env, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n",
				i, linfo[i].insn_off, prev_offset,
				prog->len);
			err = -EINVAL;
			goto err_free;
		}

		if (!prog->insnsi[linfo[i].insn_off].code) {
			verbose(env,
				"Invalid insn code at line_info[%u].insn_off\n",
				i);
			err = -EINVAL;
			goto err_free;
		}

		if (!btf_name_by_offset(btf, linfo[i].line_off) ||
		    !btf_name_by_offset(btf, linfo[i].file_name_off)) {
			verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i);
			err = -EINVAL;
			goto err_free;
		}

		if (s != env->subprog_cnt) {
			if (linfo[i].insn_off == sub[s].start) {
				sub[s].linfo_idx = i;
				s++;
			} else if (sub[s].start < linfo[i].insn_off) {
				verbose(env, "missing bpf_line_info for func#%u\n", s);
				err = -EINVAL;
				goto err_free;
			}
		}

		prev_offset = linfo[i].insn_off;
		ulinfo += rec_size;
	}

	if (s != env->subprog_cnt) {
		verbose(env, "missing bpf_line_info for %u funcs starting from func#%u\n",
			env->subprog_cnt - s, s);
		err = -EINVAL;
		goto err_free;
	}

	prog->aux->linfo = linfo;
	prog->aux->nr_linfo = nr_linfo;

	return 0;

err_free:
	kvfree(linfo);
	return err;
}

Project: linux
File: verifier.c

static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
					    const struct bpf_insn *patch, u32 len)
{
	struct bpf_prog *new_prog;

	new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
	if (IS_ERR(new_prog)) {
		if (PTR_ERR(new_prog) == -ERANGE)
			verbose(env,
				"insn %d cannot be patched due to 16-bit range\n",
				env->insn_aux_data[off].orig_idx);
		return NULL;
	}
	if (adjust_insn_aux_data(env, new_prog, off, len))
		return NULL;
	adjust_subprog_starts(env, off, len);
	return new_prog;
}

Project: linux
File: verifier.c

static void scalar_min_max_sub(struct bpf_reg_state *dst_reg,
			       struct bpf_reg_state *src_reg)
{
	s64 smin_val = src_reg->smin_value;
	s64 smax_val = src_reg->smax_value;
	u64 umin_val = src_reg->umin_value;
	u64 umax_val = src_reg->umax_value;

	if (signed_sub_overflows(dst_reg->smin_value, smax_val) ||
	    signed_sub_overflows(dst_reg->smax_value, smin_val)) {
		/* Overflow possible, we know nothing */
		dst_reg->smin_value = S64_MIN;
		dst_reg->smax_value = S64_MAX;
	} else {
		dst_reg->smin_value -= smax_val;
		dst_reg->smax_value -= smin_val;
	}
	if (dst_reg->umin_value < umax_val) {
		/* Overflow possible, we know nothing */
		dst_reg->umin_value = 0;
		dst_reg->umax_value = U64_MAX;
	} else {
		/* Cannot overflow (as long as bounds are consistent) */
		dst_reg->umin_value -= umax_val;
		dst_reg->umax_value -= umin_val;
	}
	dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg->var_off);
}

Project: linux
File: verifier.c

static void __reg_deduce_bounds(struct bpf_reg_state *reg)
{
	/* Learn sign from signed bounds.
	 * If we cannot cross the sign boundary, then signed and unsigned bounds
	 * are the same, so combine.  This works even in the negative case, e.g.
	 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
	 */
	if (reg->smin_value >= 0 || reg->smax_value < 0) {
		reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
							  reg->umin_value);
		reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
							  reg->umax_value);
		return;
	}
	/* Learn sign from unsigned bounds.  Signed bounds cross the sign
	 * boundary, so we must be careful.
	 */
	if ((s64)reg->umax_value >= 0) {
		/* Positive.  We can't learn anything from the smin, but smax
		 * is positive, hence safe.
		 */
		reg->smin_value = reg->umin_value;
		reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
							  reg->umax_value);
	} else if ((s64)reg->umin_value < 0) {
		/* Negative.  We can't learn anything from the smax, but smin
		 * is negative, hence safe.
		 */
		reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
							  reg->umin_value);
		reg->smax_value = reg->umax_value;
	}
}

Project: linux
File: verifier.c

static int bpf_map_direct_read(struct bpf_map *map, int off, int size, u64 *val)
{
	void *ptr;
	u64 addr;
	int err;

	err = map->ops->map_direct_value_addr(map, &addr, off);
	if (err)
		return err;
	ptr = (void *)(long)addr + off;

	switch (size) {
	case sizeof(u8):
		*val = (u64)*(u8 *)ptr;
		break;
	case sizeof(u16):
		*val = (u64)*(u16 *)ptr;
		break;
	case sizeof(u32):
		*val = (u64)*(u32 *)ptr;
		break;
	case sizeof(u64):
		*val = *(u64 *)ptr;
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

Project: linux
File: verifier.c

static int check_ptr_alignment(struct bpf_verifier_env *env,
			       const struct bpf_reg_state *reg, int off,
			       int size, bool strict_alignment_once)
{
	bool strict = env->strict_alignment || strict_alignment_once;
	const char *pointer_desc = "";

	switch (reg->type) {
	case PTR_TO_PACKET:
	case PTR_TO_PACKET_META:
		/* Special case, because of NET_IP_ALIGN. Given metadata sits
		 * right in front, treat it the very same way.
		 */
		return check_pkt_ptr_alignment(env, reg, off, size, strict);
	case PTR_TO_FLOW_KEYS:
		pointer_desc = "flow keys ";
		break;
	case PTR_TO_MAP_VALUE:
		pointer_desc = "value ";
		break;
	case PTR_TO_CTX:
		pointer_desc = "context ";
		break;
	case PTR_TO_STACK:
		pointer_desc = "stack ";
		/* The stack spill tracking logic in check_stack_write()
		 * and check_stack_read() relies on stack accesses being
		 * aligned.
		 */
		strict = true;
		break;
	case PTR_TO_SOCKET:
		pointer_desc = "sock ";
		break;
	case PTR_TO_SOCK_COMMON:
		pointer_desc = "sock_common ";
		break;
	case PTR_TO_TCP_SOCK:
		pointer_desc = "tcp_sock ";
		break;
	case PTR_TO_XDP_SOCK:
		pointer_desc = "xdp_sock ";
		break;
	default:
		break;
	}
	return check_generic_ptr_alignment(env, reg, pointer_desc, off, size,
					   strict);
}

Project: linux
File: verifier.c

static int check_map_prog_compatibility(struct bpf_verifier_env *env,
					struct bpf_map *map,
					struct bpf_prog *prog)

{
	/*
	 * Validate that trace type programs use preallocated hash maps.
	 *
	 * For programs attached to PERF events this is mandatory as the
	 * perf NMI can hit any arbitrary code sequence.
	 *
	 * All other trace types using preallocated hash maps are unsafe as
	 * well because tracepoint or kprobes can be inside locked regions
	 * of the memory allocator or at a place where a recursion into the
	 * memory allocator would see inconsistent state.
	 *
	 * On RT enabled kernels run-time allocation of all trace type
	 * programs is strictly prohibited due to lock type constraints. On
	 * !RT kernels it is allowed for backwards compatibility reasons for
	 * now, but warnings are emitted so developers are made aware of
	 * the unsafety and can fix their programs before this is enforced.
	 */
	if (is_tracing_prog_type(prog->type) && !is_preallocated_map(map)) {
		if (prog->type == BPF_PROG_TYPE_PERF_EVENT) {
			verbose(env, "perf_event programs can only use preallocated hash map\n");
			return -EINVAL;
		}
		if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
			verbose(env, "trace type programs can only use preallocated hash map\n");
			return -EINVAL;
		}
		WARN_ONCE(1, "trace type BPF program uses run-time allocation\n");
		verbose(env, "trace type programs with run-time allocated hash maps are unsafe. Switch to preallocated hash maps.\n");
	}

	if ((is_tracing_prog_type(prog->type) ||
	     prog->type == BPF_PROG_TYPE_SOCKET_FILTER) &&
	    map_value_has_spin_lock(map)) {
		verbose(env, "tracing progs cannot use bpf_spin_lock yet\n");
		return -EINVAL;
	}

	if ((bpf_prog_is_dev_bound(prog->aux) || bpf_map_is_dev_bound(map)) &&
	    !bpf_offload_prog_map_match(prog, map)) {
		verbose(env, "offload device mismatch between prog and map\n");
		return -EINVAL;
	}

	if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
		verbose(env, "bpf_struct_ops map cannot be used in prog\n");
		return -EINVAL;
	}

	return 0;
}

Project: linux
File: verifier.c

static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
			     u32 regno, int off, int size,
			     enum bpf_access_type t)
{
	struct bpf_reg_state *regs = cur_regs(env);
	struct bpf_reg_state *reg = &regs[regno];
	struct bpf_insn_access_aux info = {};
	bool valid;

	if (reg->smin_value < 0) {
		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
			regno);
		return -EACCES;
	}

	switch (reg->type) {
	case PTR_TO_SOCK_COMMON:
		valid = bpf_sock_common_is_valid_access(off, size, t, &info);
		break;
	case PTR_TO_SOCKET:
		valid = bpf_sock_is_valid_access(off, size, t, &info);
		break;
	case PTR_TO_TCP_SOCK:
		valid = bpf_tcp_sock_is_valid_access(off, size, t, &info);
		break;
	case PTR_TO_XDP_SOCK:
		valid = bpf_xdp_sock_is_valid_access(off, size, t, &info);
		break;
	default:
		valid = false;
	}


	if (valid) {
		env->insn_aux_data[insn_idx].ctx_field_size =
			info.ctx_field_size;
		return 0;
	}

	verbose(env, "R%d invalid %s access off=%d size=%d\n",
		regno, reg_type_str[reg->type], off, size);

	return -EACCES;
}

Project: linux
File: verifier.c

static bool bpf_map_is_cgroup_storage(struct bpf_map *map)
{
	return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE ||
		map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
}

Project: linux
File: verifier.c

static bool stacksafe(struct bpf_func_state *old,
		      struct bpf_func_state *cur,
		      struct idpair *idmap)
{
	int i, spi;

	/* walk slots of the explored stack and ignore any additional
	 * slots in the current stack, since explored(safe) state
	 * didn't use them
	 */
	for (i = 0; i < old->allocated_stack; i++) {
		spi = i / BPF_REG_SIZE;

		if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)) {
			i += BPF_REG_SIZE - 1;
			/* explored state didn't use this */
			continue;
		}

		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID)
			continue;

		/* explored stack has more populated slots than current stack
		 * and these slots were used
		 */
		if (i >= cur->allocated_stack)
			return false;

		/* if old state was safe with misc data in the stack
		 * it will be safe with zero-initialized stack.
		 * The opposite is not true
		 */
		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC &&
		    cur->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_ZERO)
			continue;
		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
		    cur->stack[spi].slot_type[i % BPF_REG_SIZE])
			/* Ex: old explored (safe) state has STACK_SPILL in
			 * this stack slot, but current has has STACK_MISC ->
			 * this verifier states are not equivalent,
			 * return false to continue verification of this path
			 */
			return false;
		if (i % BPF_REG_SIZE)
			continue;
		if (old->stack[spi].slot_type[0] != STACK_SPILL)
			continue;
		if (!regsafe(&old->stack[spi].spilled_ptr,
			     &cur->stack[spi].spilled_ptr,
			     idmap))
			/* when explored and current stack slot are both storing
			 * spilled registers, check that stored pointers types
			 * are the same as well.
			 * Ex: explored safe path could have stored
			 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8}
			 * but current path has stored:
			 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16}
			 * such verifier states are not equivalent.
			 * return false to continue verification of this path
			 */
			return false;
	}
	return true;
}

Project: linux
File: verifier.c

static void scalar_min_max_rsh(struct bpf_reg_state *dst_reg,
			       struct bpf_reg_state *src_reg)
{
	u64 umax_val = src_reg->umax_value;
	u64 umin_val = src_reg->umin_value;

	/* BPF_RSH is an unsigned shift.  If the value in dst_reg might
	 * be negative, then either:
	 * 1) src_reg might be zero, so the sign bit of the result is
	 *    unknown, so we lose our signed bounds
	 * 2) it's known negative, thus the unsigned bounds capture the
	 *    signed bounds
	 * 3) the signed bounds cross zero, so they tell us nothing
	 *    about the result
	 * If the value in dst_reg is known nonnegative, then again the
	 * unsigned bounts capture the signed bounds.
	 * Thus, in all cases it suffices to blow away our signed bounds
	 * and rely on inferring new ones from the unsigned bounds and
	 * var_off of the result.
	 */
	dst_reg->smin_value = S64_MIN;
	dst_reg->smax_value = S64_MAX;
	dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val);
	dst_reg->umin_value >>= umax_val;
	dst_reg->umax_value >>= umin_val;
	/* We may learn something more from the var_off */
	__update_reg_bounds(dst_reg);
}

Project: linux
File: verifier.c

static void print_liveness(struct bpf_verifier_env *env,
			   enum bpf_reg_liveness live)
{
	if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN | REG_LIVE_DONE))
	    verbose(env, "_");
	if (live & REG_LIVE_READ)
		verbose(env, "r");
	if (live & REG_LIVE_WRITTEN)
		verbose(env, "w");
	if (live & REG_LIVE_DONE)
		verbose(env, "D");
}

Project: linux
File: verifier.c

static void __mark_reg_const_zero(struct bpf_reg_state *reg)
{
	__mark_reg_known(reg, 0);
	reg->type = SCALAR_VALUE;
}

Project: linux
File: verifier.c

static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
				   struct bpf_insn *insn)
{
	struct bpf_verifier_state *vstate = env->cur_state;
	struct bpf_func_state *state = vstate->frame[vstate->curframe];
	struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg;
	struct bpf_reg_state *ptr_reg = NULL, off_reg = {0};
	u8 opcode = BPF_OP(insn->code);
	int err;

	dst_reg = &regs[insn->dst_reg];
	src_reg = NULL;
	if (dst_reg->type != SCALAR_VALUE)
		ptr_reg = dst_reg;
	if (BPF_SRC(insn->code) == BPF_X) {
		src_reg = &regs[insn->src_reg];
		if (src_reg->type != SCALAR_VALUE) {
			if (dst_reg->type != SCALAR_VALUE) {
				/* Combining two pointers by any ALU op yields
				 * an arbitrary scalar. Disallow all math except
				 * pointer subtraction
				 */
				if (opcode == BPF_SUB && env->allow_ptr_leaks) {
					mark_reg_unknown(env, regs, insn->dst_reg);
					return 0;
				}
				verbose(env, "R%d pointer %s pointer prohibited\n",
					insn->dst_reg,
					bpf_alu_string[opcode >> 4]);
				return -EACCES;
			} else {
				/* scalar += pointer
				 * This is legal, but we have to reverse our
				 * src/dest handling in computing the range
				 */
				err = mark_chain_precision(env, insn->dst_reg);
				if (err)
					return err;
				return adjust_ptr_min_max_vals(env, insn,
							       src_reg, dst_reg);
			}
		} else if (ptr_reg) {
			/* pointer += scalar */
			err = mark_chain_precision(env, insn->src_reg);
			if (err)
				return err;
			return adjust_ptr_min_max_vals(env, insn,
						       dst_reg, src_reg);
		}
	} else {
		/* Pretend the src is a reg with a known value, since we only
		 * need to be able to read from this state.
		 */
		off_reg.type = SCALAR_VALUE;
		__mark_reg_known(&off_reg, insn->imm);
		src_reg = &off_reg;
		if (ptr_reg) /* pointer += K */
			return adjust_ptr_min_max_vals(env, insn,
						       ptr_reg, src_reg);
	}

	/* Got here implies adding two SCALAR_VALUEs */
	if (WARN_ON_ONCE(ptr_reg)) {
		print_verifier_state(env, state);
		verbose(env, "verifier internal error: unexpected ptr_reg\n");
		return -EINVAL;
	}
	if (WARN_ON(!src_reg)) {
		print_verifier_state(env, state);
		verbose(env, "verifier internal error: no src_reg\n");
		return -EINVAL;
	}
	return adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg);
}

Project: linux
File: verifier.c

static void __clear_all_pkt_pointers(struct bpf_verifier_env *env,
				     struct bpf_func_state *state)
{
	struct bpf_reg_state *regs = state->regs, *reg;
	int i;

	for (i = 0; i < MAX_BPF_REG; i++)
		if (reg_is_pkt_pointer_any(&regs[i]))
			mark_reg_unknown(env, regs, i);

	bpf_for_each_spilled_reg(i, state, reg) {
		if (!reg)
			continue;
		if (reg_is_pkt_pointer_any(reg))
			__mark_reg_unknown(env, reg);
	}
}

Project: linux
File: verifier.c

static u64 gen_hi_max(struct tnum var)
{
	return (var.value | var.mask) & ~0xffffffffULL;
}

Project: linux
File: verifier.c

static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
{
	struct bpf_reg_state *regs = cur_regs(env);
	static const int ctx_reg = BPF_REG_6;
	u8 mode = BPF_MODE(insn->code);
	int i, err;

	if (!may_access_skb(env->prog->type)) {
		verbose(env, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
		return -EINVAL;
	}

	if (!env->ops->gen_ld_abs) {
		verbose(env, "bpf verifier is misconfigured\n");
		return -EINVAL;
	}

	if (env->subprog_cnt > 1) {
		/* when program has LD_ABS insn JITs and interpreter assume
		 * that r1 == ctx == skb which is not the case for callees
		 * that can have arbitrary arguments. It's problematic
		 * for main prog as well since JITs would need to analyze
		 * all functions in order to make proper register save/restore
		 * decisions in the main prog. Hence disallow LD_ABS with calls
		 */
		verbose(env, "BPF_LD_[ABS|IND] instructions cannot be mixed with bpf-to-bpf calls\n");
		return -EINVAL;
	}

	if (insn->dst_reg != BPF_REG_0 || insn->off != 0 ||
	    BPF_SIZE(insn->code) == BPF_DW ||
	    (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) {
		verbose(env, "BPF_LD_[ABS|IND] uses reserved fields\n");
		return -EINVAL;
	}

	/* check whether implicit source operand (register R6) is readable */
	err = check_reg_arg(env, ctx_reg, SRC_OP);
	if (err)
		return err;

	/* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as
	 * gen_ld_abs() may terminate the program at runtime, leading to
	 * reference leak.
	 */
	err = check_reference_leak(env);
	if (err) {
		verbose(env, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n");
		return err;
	}

	if (env->cur_state->active_spin_lock) {
		verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
		return -EINVAL;
	}

	if (regs[ctx_reg].type != PTR_TO_CTX) {
		verbose(env,
			"at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
		return -EINVAL;
	}

	if (mode == BPF_IND) {
		/* check explicit source operand */
		err = check_reg_arg(env, insn->src_reg, SRC_OP);
		if (err)
			return err;
	}

	err = check_ctx_reg(env, &regs[ctx_reg], ctx_reg);
	if (err < 0)
		return err;

	/* reset caller saved regs to unreadable */
	for (i = 0; i < CALLER_SAVED_REGS; i++) {
		mark_reg_not_init(env, regs, caller_saved[i]);
		check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
	}

	/* mark destination R0 register as readable, since it contains
	 * the value fetched from the packet.
	 * Already marked as written above.
	 */
	mark_reg_unknown(env, regs, BPF_REG_0);
	/* ld_abs load up to 32-bit skb data. */
	regs[BPF_REG_0].subreg_def = env->insn_idx + 1;
	return 0;
}

Project: linux
File: verifier.c

static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev)
{
	return src != prev && (!reg_type_mismatch_ok(src) ||
			       !reg_type_mismatch_ok(prev));
}

Project: linux
File: verifier.c

static int propagate_liveness_reg(struct bpf_verifier_env *env,
				  struct bpf_reg_state *reg,
				  struct bpf_reg_state *parent_reg)
{
	u8 parent_flag = parent_reg->live & REG_LIVE_READ;
	u8 flag = reg->live & REG_LIVE_READ;
	int err;

	/* When comes here, read flags of PARENT_REG or REG could be any of
	 * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need
	 * of propagation if PARENT_REG has strongest REG_LIVE_READ64.
	 */
	if (parent_flag == REG_LIVE_READ64 ||
	    /* Or if there is no read flag from REG. */
	    !flag ||
	    /* Or if the read flag from REG is the same as PARENT_REG. */
	    parent_flag == flag)
		return 0;

	err = mark_reg_read(env, reg, parent_reg, flag);
	if (err)
		return err;

	return flag;
}

Project: linux
File: verifier.c

static bool states_equal(struct bpf_verifier_env *env,
			 struct bpf_verifier_state *old,
			 struct bpf_verifier_state *cur)
{
	int i;

	if (old->curframe != cur->curframe)
		return false;

	/* Verification state from speculative execution simulation
	 * must never prune a non-speculative execution one.
	 */
	if (old->speculative && !cur->speculative)
		return false;

	if (old->active_spin_lock != cur->active_spin_lock)
		return false;

	/* for states to be equal callsites have to be the same
	 * and all frame states need to be equivalent
	 */
	for (i = 0; i <= old->curframe; i++) {
		if (old->frame[i]->callsite != cur->frame[i]->callsite)
			return false;
		if (!func_states_equal(old->frame[i], cur->frame[i]))
			return false;
	}
	return true;
}

Project: linux
File: verifier.c

static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
{
	struct bpf_insn *insn = env->prog->insnsi;
	int insn_cnt = env->prog->len;
	int i, j, err;

	err = bpf_prog_calc_tag(env->prog);
	if (err)
		return err;

	for (i = 0; i < insn_cnt; i++, insn++) {
		if (BPF_CLASS(insn->code) == BPF_LDX &&
		    (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0)) {
			verbose(env, "BPF_LDX uses reserved fields\n");
			return -EINVAL;
		}

		if (BPF_CLASS(insn->code) == BPF_STX &&
		    ((BPF_MODE(insn->code) != BPF_MEM &&
		      BPF_MODE(insn->code) != BPF_XADD) || insn->imm != 0)) {
			verbose(env, "BPF_STX uses reserved fields\n");
			return -EINVAL;
		}

		if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) {
			struct bpf_insn_aux_data *aux;
			struct bpf_map *map;
			struct fd f;
			u64 addr;

			if (i == insn_cnt - 1 || insn[1].code != 0 ||
			    insn[1].dst_reg != 0 || insn[1].src_reg != 0 ||
			    insn[1].off != 0) {
				verbose(env, "invalid bpf_ld_imm64 insn\n");
				return -EINVAL;
			}

			if (insn[0].src_reg == 0)
				/* valid generic load 64-bit imm */
				goto next_insn;

			/* In final convert_pseudo_ld_imm64() step, this is
			 * converted into regular 64-bit imm load insn.
			 */
			if ((insn[0].src_reg != BPF_PSEUDO_MAP_FD &&
			     insn[0].src_reg != BPF_PSEUDO_MAP_VALUE) ||
			    (insn[0].src_reg == BPF_PSEUDO_MAP_FD &&
			     insn[1].imm != 0)) {
				verbose(env,
					"unrecognized bpf_ld_imm64 insn\n");
				return -EINVAL;
			}

			f = fdget(insn[0].imm);
			map = __bpf_map_get(f);
			if (IS_ERR(map)) {
				verbose(env, "fd %d is not pointing to valid bpf_map\n",
					insn[0].imm);
				return PTR_ERR(map);
			}

			err = check_map_prog_compatibility(env, map, env->prog);
			if (err) {
				fdput(f);
				return err;
			}

			aux = &env->insn_aux_data[i];
			if (insn->src_reg == BPF_PSEUDO_MAP_FD) {
				addr = (unsigned long)map;
			} else {
				u32 off = insn[1].imm;

				if (off >= BPF_MAX_VAR_OFF) {
					verbose(env, "direct value offset of %u is not allowed\n", off);
					fdput(f);
					return -EINVAL;
				}

				if (!map->ops->map_direct_value_addr) {
					verbose(env, "no direct value access support for this map type\n");
					fdput(f);
					return -EINVAL;
				}

				err = map->ops->map_direct_value_addr(map, &addr, off);
				if (err) {
					verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n",
						map->value_size, off);
					fdput(f);
					return err;
				}

				aux->map_off = off;
				addr += off;
			}

			insn[0].imm = (u32)addr;
			insn[1].imm = addr >> 32;

			/* check whether we recorded this map already */
			for (j = 0; j < env->used_map_cnt; j++) {
				if (env->used_maps[j] == map) {
					aux->map_index = j;
					fdput(f);
					goto next_insn;
				}
			}

			if (env->used_map_cnt >= MAX_USED_MAPS) {
				fdput(f);
				return -E2BIG;
			}

			/* hold the map. If the program is rejected by verifier,
			 * the map will be released by release_maps() or it
			 * will be used by the valid program until it's unloaded
			 * and all maps are released in free_used_maps()
			 */
			bpf_map_inc(map);

			aux->map_index = env->used_map_cnt;
			env->used_maps[env->used_map_cnt++] = map;

			if (bpf_map_is_cgroup_storage(map) &&
			    bpf_cgroup_storage_assign(env->prog->aux, map)) {
				verbose(env, "only one cgroup storage of each type is allowed\n");
				fdput(f);
				return -EBUSY;
			}

			fdput(f);
next_insn:
			insn++;
			i++;
			continue;
		}

		/* Basic sanity check before we invest more work here. */
		if (!bpf_opcode_in_insntable(insn->code)) {
			verbose(env, "unknown opcode %02x\n", insn->code);
			return -EINVAL;
		}
	}

	/* now all pseudo BPF_LD_IMM64 instructions load valid
	 * 'struct bpf_map *' into a register instead of user map_fd.
	 * These pointers will be used later by verifier to validate map access.
	 */
	return 0;
}

Project: linux
File: verifier.c

static int do_check_subprogs(struct bpf_verifier_env *env)
{
	struct bpf_prog_aux *aux = env->prog->aux;
	int i, ret;

	if (!aux->func_info)
		return 0;

	for (i = 1; i < env->subprog_cnt; i++) {
		if (aux->func_info_aux[i].linkage != BTF_FUNC_GLOBAL)
			continue;
		env->insn_idx = env->subprog_info[i].start;
		WARN_ON_ONCE(env->insn_idx == 0);
		ret = do_check_common(env, i);
		if (ret) {
			return ret;
		} else if (env->log.level & BPF_LOG_LEVEL) {
			verbose(env,
				"Func#%d is safe for any args that match its prototype\n",
				i);
		}
	}
	return 0;
}

Project: linux
File: verifier.c

static void release_maps(struct bpf_verifier_env *env)
{
	__bpf_free_used_maps(env->prog->aux, env->used_maps,
			     env->used_map_cnt);
}

Project: linux
File: verifier.c

static void mark_insn_zext(struct bpf_verifier_env *env,
			   struct bpf_reg_state *reg)
{
	s32 def_idx = reg->subreg_def;

	if (def_idx == DEF_NOT_SUBREG)
		return;

	env->insn_aux_data[def_idx - 1].zext_dst = true;
	/* The dst will be zero extended, so won't be sub-register anymore. */
	reg->subreg_def = DEF_NOT_SUBREG;
}

Project: linux
File: verifier.c

static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
{
	return type == PTR_TO_SOCKET ||
		type == PTR_TO_SOCKET_OR_NULL ||
		type == PTR_TO_TCP_SOCK ||
		type == PTR_TO_TCP_SOCK_OR_NULL;
}

Project: linux
File: verifier.c

static void __mark_reg_not_init(const struct bpf_verifier_env *env,
				struct bpf_reg_state *reg)
{
	__mark_reg_unknown(env, reg);
	reg->type = NOT_INIT;
}

Project: linux
File: verifier.c

static int jit_subprogs(struct bpf_verifier_env *env)
{
	struct bpf_prog *prog = env->prog, **func, *tmp;
	int i, j, subprog_start, subprog_end = 0, len, subprog;
	struct bpf_insn *insn;
	void *old_bpf_func;
	int err;

	if (env->subprog_cnt <= 1)
		return 0;

	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
		if (insn->code != (BPF_JMP | BPF_CALL) ||
		    insn->src_reg != BPF_PSEUDO_CALL)
			continue;
		/* Upon error here we cannot fall back to interpreter but
		 * need a hard reject of the program. Thus -EFAULT is
		 * propagated in any case.
		 */
		subprog = find_subprog(env, i + insn->imm + 1);
		if (subprog < 0) {
			WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
				  i + insn->imm + 1);
			return -EFAULT;
		}
		/* temporarily remember subprog id inside insn instead of
		 * aux_data, since next loop will split up all insns into funcs
		 */
		insn->off = subprog;
		/* remember original imm in case JIT fails and fallback
		 * to interpreter will be needed
		 */
		env->insn_aux_data[i].call_imm = insn->imm;
		/* point imm to __bpf_call_base+1 from JITs point of view */
		insn->imm = 1;
	}

	err = bpf_prog_alloc_jited_linfo(prog);
	if (err)
		goto out_undo_insn;

	err = -ENOMEM;
	func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL);
	if (!func)
		goto out_undo_insn;

	for (i = 0; i < env->subprog_cnt; i++) {
		subprog_start = subprog_end;
		subprog_end = env->subprog_info[i + 1].start;

		len = subprog_end - subprog_start;
		/* BPF_PROG_RUN doesn't call subprogs directly,
		 * hence main prog stats include the runtime of subprogs.
		 * subprogs don't have IDs and not reachable via prog_get_next_id
		 * func[i]->aux->stats will never be accessed and stays NULL
		 */
		func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER);
		if (!func[i])
			goto out_free;
		memcpy(func[i]->insnsi, &prog->insnsi[subprog_start],
		       len * sizeof(struct bpf_insn));
		func[i]->type = prog->type;
		func[i]->len = len;
		if (bpf_prog_calc_tag(func[i]))
			goto out_free;
		func[i]->is_func = 1;
		func[i]->aux->func_idx = i;
		/* the btf and func_info will be freed only at prog->aux */
		func[i]->aux->btf = prog->aux->btf;
		func[i]->aux->func_info = prog->aux->func_info;

		/* Use bpf_prog_F_tag to indicate functions in stack traces.
		 * Long term would need debug info to populate names
		 */
		func[i]->aux->name[0] = 'F';
		func[i]->aux->stack_depth = env->subprog_info[i].stack_depth;
		func[i]->jit_requested = 1;
		func[i]->aux->linfo = prog->aux->linfo;
		func[i]->aux->nr_linfo = prog->aux->nr_linfo;
		func[i]->aux->jited_linfo = prog->aux->jited_linfo;
		func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx;
		func[i] = bpf_int_jit_compile(func[i]);
		if (!func[i]->jited) {
			err = -ENOTSUPP;
			goto out_free;
		}
		cond_resched();
	}
	/* at this point all bpf functions were successfully JITed
	 * now populate all bpf_calls with correct addresses and
	 * run last pass of JIT
	 */
	for (i = 0; i < env->subprog_cnt; i++) {
		insn = func[i]->insnsi;
		for (j = 0; j < func[i]->len; j++, insn++) {
			if (insn->code != (BPF_JMP | BPF_CALL) ||
			    insn->src_reg != BPF_PSEUDO_CALL)
				continue;
			subprog = insn->off;
			insn->imm = BPF_CAST_CALL(func[subprog]->bpf_func) -
				    __bpf_call_base;
		}

		/* we use the aux data to keep a list of the start addresses
		 * of the JITed images for each function in the program
		 *
		 * for some architectures, such as powerpc64, the imm field
		 * might not be large enough to hold the offset of the start
		 * address of the callee's JITed image from __bpf_call_base
		 *
		 * in such cases, we can lookup the start address of a callee
		 * by using its subprog id, available from the off field of
		 * the call instruction, as an index for this list
		 */
		func[i]->aux->func = func;
		func[i]->aux->func_cnt = env->subprog_cnt;
	}
	for (i = 0; i < env->subprog_cnt; i++) {
		old_bpf_func = func[i]->bpf_func;
		tmp = bpf_int_jit_compile(func[i]);
		if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) {
			verbose(env, "JIT doesn't support bpf-to-bpf calls\n");
			err = -ENOTSUPP;
			goto out_free;
		}
		cond_resched();
	}

	/* finally lock prog and jit images for all functions and
	 * populate kallsysm
	 */
	for (i = 0; i < env->subprog_cnt; i++) {
		bpf_prog_lock_ro(func[i]);
		bpf_prog_kallsyms_add(func[i]);
	}

	/* Last step: make now unused interpreter insns from main
	 * prog consistent for later dump requests, so they can
	 * later look the same as if they were interpreted only.
	 */
	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
		if (insn->code != (BPF_JMP | BPF_CALL) ||
		    insn->src_reg != BPF_PSEUDO_CALL)
			continue;
		insn->off = env->insn_aux_data[i].call_imm;
		subprog = find_subprog(env, i + insn->off + 1);
		insn->imm = subprog;
	}

	prog->jited = 1;
	prog->bpf_func = func[0]->bpf_func;
	prog->aux->func = func;
	prog->aux->func_cnt = env->subprog_cnt;
	bpf_prog_free_unused_jited_linfo(prog);
	return 0;
out_free:
	for (i = 0; i < env->subprog_cnt; i++)
		if (func[i])
			bpf_jit_free(func[i]);
	kfree(func);
out_undo_insn:
	/* cleanup main prog to be interpreted */
	prog->jit_requested = 0;
	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
		if (insn->code != (BPF_JMP | BPF_CALL) ||
		    insn->src_reg != BPF_PSEUDO_CALL)
			continue;
		insn->off = 0;
		insn->imm = env->insn_aux_data[i].call_imm;
	}
	bpf_prog_free_jited_linfo(prog);
	return err;
}

Project: linux
File: verifier.c

static int check_stack_write(struct bpf_verifier_env *env,
			     struct bpf_func_state *state, /* func where register points to */
			     int off, int size, int value_regno, int insn_idx)
{
	struct bpf_func_state *cur; /* state of the current function */
	int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err;
	u32 dst_reg = env->prog->insnsi[insn_idx].dst_reg;
	struct bpf_reg_state *reg = NULL;

	err = realloc_func_state(state, round_up(slot + 1, BPF_REG_SIZE),
				 state->acquired_refs, true);
	if (err)
		return err;
	/* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
	 * so it's aligned access and [off, off + size) are within stack limits
	 */
	if (!env->allow_ptr_leaks &&
	    state->stack[spi].slot_type[0] == STACK_SPILL &&
	    size != BPF_REG_SIZE) {
		verbose(env, "attempt to corrupt spilled pointer on stack\n");
		return -EACCES;
	}

	cur = env->cur_state->frame[env->cur_state->curframe];
	if (value_regno >= 0)
		reg = &cur->regs[value_regno];

	if (reg && size == BPF_REG_SIZE && register_is_const(reg) &&
	    !register_is_null(reg) && env->allow_ptr_leaks) {
		if (dst_reg != BPF_REG_FP) {
			/* The backtracking logic can only recognize explicit
			 * stack slot address like [fp - 8]. Other spill of
			 * scalar via different register has to be conervative.
			 * Backtrack from here and mark all registers as precise
			 * that contributed into 'reg' being a constant.
			 */
			err = mark_chain_precision(env, value_regno);
			if (err)
				return err;
		}
		save_register_state(state, spi, reg);
	} else if (reg && is_spillable_regtype(reg->type)) {
		/* register containing pointer is being spilled into stack */
		if (size != BPF_REG_SIZE) {
			verbose_linfo(env, insn_idx, "; ");
			verbose(env, "invalid size of register spill\n");
			return -EACCES;
		}

		if (state != cur && reg->type == PTR_TO_STACK) {
			verbose(env, "cannot spill pointers to stack into stack frame of the caller\n");
			return -EINVAL;
		}

		if (!env->allow_ptr_leaks) {
			bool sanitize = false;

			if (state->stack[spi].slot_type[0] == STACK_SPILL &&
			    register_is_const(&state->stack[spi].spilled_ptr))
				sanitize = true;
			for (i = 0; i < BPF_REG_SIZE; i++)
				if (state->stack[spi].slot_type[i] == STACK_MISC) {
					sanitize = true;
					break;
				}
			if (sanitize) {
				int *poff = &env->insn_aux_data[insn_idx].sanitize_stack_off;
				int soff = (-spi - 1) * BPF_REG_SIZE;

				/* detected reuse of integer stack slot with a pointer
				 * which means either llvm is reusing stack slot or
				 * an attacker is trying to exploit CVE-2018-3639
				 * (speculative store bypass)
				 * Have to sanitize that slot with preemptive
				 * store of zero.
				 */
				if (*poff && *poff != soff) {
					/* disallow programs where single insn stores
					 * into two different stack slots, since verifier
					 * cannot sanitize them
					 */
					verbose(env,
						"insn %d cannot access two stack slots fp%d and fp%d",
						insn_idx, *poff, soff);
					return -EINVAL;
				}
				*poff = soff;
			}
		}
		save_register_state(state, spi, reg);
	} else {
		u8 type = STACK_MISC;

		/* regular write of data into stack destroys any spilled ptr */
		state->stack[spi].spilled_ptr.type = NOT_INIT;
		/* Mark slots as STACK_MISC if they belonged to spilled ptr. */
		if (state->stack[spi].slot_type[0] == STACK_SPILL)
			for (i = 0; i < BPF_REG_SIZE; i++)
				state->stack[spi].slot_type[i] = STACK_MISC;

		/* only mark the slot as written if all 8 bytes were written
		 * otherwise read propagation may incorrectly stop too soon
		 * when stack slots are partially written.
		 * This heuristic means that read propagation will be
		 * conservative, since it will add reg_live_read marks
		 * to stack slots all the way to first state when programs
		 * writes+reads less than 8 bytes
		 */
		if (size == BPF_REG_SIZE)
			state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;

		/* when we zero initialize stack slots mark them as such */
		if (reg && register_is_null(reg)) {
			/* backtracking doesn't work for STACK_ZERO yet. */
			err = mark_chain_precision(env, value_regno);
			if (err)
				return err;
			type = STACK_ZERO;
		}

		/* Mark slots affected by this stack write. */
		for (i = 0; i < size; i++)
			state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] =
				type;
	}
	return 0;
}

Project: linux
File: verifier.c

static int check_map_access_type(struct bpf_verifier_env *env, u32 regno,
				 int off, int size, enum bpf_access_type type)
{
	struct bpf_reg_state *regs = cur_regs(env);
	struct bpf_map *map = regs[regno].map_ptr;
	u32 cap = bpf_map_flags_to_cap(map);

	if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) {
		verbose(env, "write into map forbidden, value_size=%d off=%d size=%d\n",
			map->value_size, off, size);
		return -EACCES;
	}

	if (type == BPF_READ && !(cap & BPF_MAP_CAN_READ)) {
		verbose(env, "read from map forbidden, value_size=%d off=%d size=%d\n",
			map->value_size, off, size);
		return -EACCES;
	}

	return 0;
}

Project: linux
File: verifier.c

static void print_verification_stats(struct bpf_verifier_env *env)
{
	int i;

	if (env->log.level & BPF_LOG_STATS) {
		verbose(env, "verification time %lld usec\n",
			div_u64(env->verification_time, 1000));
		verbose(env, "stack depth ");
		for (i = 0; i < env->subprog_cnt; i++) {
			u32 depth = env->subprog_info[i].stack_depth;

			verbose(env, "%d", depth);
			if (i + 1 < env->subprog_cnt)
				verbose(env, "+");
		}
		verbose(env, "\n");
	}
	verbose(env, "processed %d insns (limit %d) max_states_per_insn %d "
		"total_states %d peak_states %d mark_read %d\n",
		env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS,
		env->max_states_per_insn, env->total_states,
		env->peak_states, env->longest_mark_read_walk);
}

Project: linux
File: verifier.c

static int check_max_stack_depth(struct bpf_verifier_env *env)
{
	int depth = 0, frame = 0, idx = 0, i = 0, subprog_end;
	struct bpf_subprog_info *subprog = env->subprog_info;
	struct bpf_insn *insn = env->prog->insnsi;
	int ret_insn[MAX_CALL_FRAMES];
	int ret_prog[MAX_CALL_FRAMES];

process_func:
	/* round up to 32-bytes, since this is granularity
	 * of interpreter stack size
	 */
	depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
	if (depth > MAX_BPF_STACK) {
		verbose(env, "combined stack size of %d calls is %d. Too large\n",
			frame + 1, depth);
		return -EACCES;
	}
continue_func:
	subprog_end = subprog[idx + 1].start;
	for (; i < subprog_end; i++) {
		if (insn[i].code != (BPF_JMP | BPF_CALL))
			continue;
		if (insn[i].src_reg != BPF_PSEUDO_CALL)
			continue;
		/* remember insn and function to return to */
		ret_insn[frame] = i + 1;
		ret_prog[frame] = idx;

		/* find the callee */
		i = i + insn[i].imm + 1;
		idx = find_subprog(env, i);
		if (idx < 0) {
			WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
				  i);
			return -EFAULT;
		}
		frame++;
		if (frame >= MAX_CALL_FRAMES) {
			verbose(env, "the call stack of %d frames is too deep !\n",
				frame);
			return -E2BIG;
		}
		goto process_func;
	}
	/* end of for() loop means the last insn of the 'subprog'
	 * was reached. Doesn't matter whether it was JA or EXIT
	 */
	if (frame == 0)
		return 0;
	depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
	frame--;
	i = ret_insn[frame];
	idx = ret_prog[frame];
	goto continue_func;
}

Project: linux
File: verifier.c

static int __check_map_access(struct bpf_verifier_env *env, u32 regno, int off,
			      int size, bool zero_size_allowed)
{
	struct bpf_reg_state *regs = cur_regs(env);
	struct bpf_map *map = regs[regno].map_ptr;

	if (off < 0 || size < 0 || (size == 0 && !zero_size_allowed) ||
	    off + size > map->value_size) {
		verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n",
			map->value_size, off, size);
		return -EACCES;
	}
	return 0;
}

Project: linux
File: verifier.c

static bool is_ptr_cast_function(enum bpf_func_id func_id)
{
	return func_id == BPF_FUNC_tcp_sock ||
		func_id == BPF_FUNC_sk_fullsock;
}

Project: linux
File: verifier.c

static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx)
{
	struct bpf_func_state *state = cur_func(env);
	int new_ofs = state->acquired_refs;
	int id, err;

	err = realloc_reference_state(state, state->acquired_refs + 1, true);
	if (err)
		return err;
	id = ++env->id_gen;
	state->refs[new_ofs].id = id;
	state->refs[new_ofs].insn_idx = insn_idx;

	return id;
}

Project: linux
File: verifier.c

static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
			      u32 *ptr_limit, u8 opcode, bool off_is_neg)
{
	bool mask_to_left = (opcode == BPF_ADD &&  off_is_neg) ||
			    (opcode == BPF_SUB && !off_is_neg);
	u32 off;

	switch (ptr_reg->type) {
	case PTR_TO_STACK:
		/* Indirect variable offset stack access is prohibited in
		 * unprivileged mode so it's not handled here.
		 */
		off = ptr_reg->off + ptr_reg->var_off.value;
		if (mask_to_left)
			*ptr_limit = MAX_BPF_STACK + off;
		else
			*ptr_limit = -off;
		return 0;
	case PTR_TO_MAP_VALUE:
		if (mask_to_left) {
			*ptr_limit = ptr_reg->umax_value + ptr_reg->off;
		} else {
			off = ptr_reg->smin_value + ptr_reg->off;
			*ptr_limit = ptr_reg->map_ptr->value_size - off;
		}
		return 0;
	default:
		return -EINVAL;
	}
}

Project: linux
File: verifier.c

static void adjust_btf_func(struct bpf_verifier_env *env)
{
	struct bpf_prog_aux *aux = env->prog->aux;
	int i;

	if (!aux->func_info)
		return;

	for (i = 0; i < env->subprog_cnt; i++)
		aux->func_info[i].insn_off = env->subprog_info[i].start;
}

Project: linux
File: verifier.c

static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
{
	const struct btf_type *t, *func_proto;
	const struct bpf_struct_ops *st_ops;
	const struct btf_member *member;
	struct bpf_prog *prog = env->prog;
	u32 btf_id, member_idx;
	const char *mname;

	btf_id = prog->aux->attach_btf_id;
	st_ops = bpf_struct_ops_find(btf_id);
	if (!st_ops) {
		verbose(env, "attach_btf_id %u is not a supported struct\n",
			btf_id);
		return -ENOTSUPP;
	}

	t = st_ops->type;
	member_idx = prog->expected_attach_type;
	if (member_idx >= btf_type_vlen(t)) {
		verbose(env, "attach to invalid member idx %u of struct %s\n",
			member_idx, st_ops->name);
		return -EINVAL;
	}

	member = &btf_type_member(t)[member_idx];
	mname = btf_name_by_offset(btf_vmlinux, member->name_off);
	func_proto = btf_type_resolve_func_ptr(btf_vmlinux, member->type,
					       NULL);
	if (!func_proto) {
		verbose(env, "attach to invalid member %s(@idx %u) of struct %s\n",
			mname, member_idx, st_ops->name);
		return -EINVAL;
	}

	if (st_ops->check_member) {
		int err = st_ops->check_member(t, member);

		if (err) {
			verbose(env, "attach to unsupported member %s of struct %s\n",
				mname, st_ops->name);
			return err;
		}
	}

	prog->aux->attach_func_proto = func_proto;
	prog->aux->attach_func_name = mname;
	env->ops = st_ops->verifier_ops;

	return 0;
}

Project: linux
File: verifier.c

static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
			  enum bpf_arg_type arg_type,
			  struct bpf_call_arg_meta *meta)
{
	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
	enum bpf_reg_type expected_type, type = reg->type;
	int err = 0;

	if (arg_type == ARG_DONTCARE)
		return 0;

	err = check_reg_arg(env, regno, SRC_OP);
	if (err)
		return err;

	if (arg_type == ARG_ANYTHING) {
		if (is_pointer_value(env, regno)) {
			verbose(env, "R%d leaks addr into helper function\n",
				regno);
			return -EACCES;
		}
		return 0;
	}

	if (type_is_pkt_pointer(type) &&
	    !may_access_direct_pkt_data(env, meta, BPF_READ)) {
		verbose(env, "helper access to the packet is not allowed\n");
		return -EACCES;
	}

	if (arg_type == ARG_PTR_TO_MAP_KEY ||
	    arg_type == ARG_PTR_TO_MAP_VALUE ||
	    arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE ||
	    arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL) {
		expected_type = PTR_TO_STACK;
		if (register_is_null(reg) &&
		    arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL)
			/* final test in check_stack_boundary() */;
		else if (!type_is_pkt_pointer(type) &&
			 type != PTR_TO_MAP_VALUE &&
			 type != expected_type)
			goto err_type;
	} else if (arg_type == ARG_CONST_SIZE ||
		   arg_type == ARG_CONST_SIZE_OR_ZERO) {
		expected_type = SCALAR_VALUE;
		if (type != expected_type)
			goto err_type;
	} else if (arg_type == ARG_CONST_MAP_PTR) {
		expected_type = CONST_PTR_TO_MAP;
		if (type != expected_type)
			goto err_type;
	} else if (arg_type == ARG_PTR_TO_CTX) {
		expected_type = PTR_TO_CTX;
		if (type != expected_type)
			goto err_type;
		err = check_ctx_reg(env, reg, regno);
		if (err < 0)
			return err;
	} else if (arg_type == ARG_PTR_TO_SOCK_COMMON) {
		expected_type = PTR_TO_SOCK_COMMON;
		/* Any sk pointer can be ARG_PTR_TO_SOCK_COMMON */
		if (!type_is_sk_pointer(type))
			goto err_type;
		if (reg->ref_obj_id) {
			if (meta->ref_obj_id) {
				verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
					regno, reg->ref_obj_id,
					meta->ref_obj_id);
				return -EFAULT;
			}
			meta->ref_obj_id = reg->ref_obj_id;
		}
	} else if (arg_type == ARG_PTR_TO_SOCKET) {
		expected_type = PTR_TO_SOCKET;
		if (type != expected_type)
			goto err_type;
	} else if (arg_type == ARG_PTR_TO_BTF_ID) {
		expected_type = PTR_TO_BTF_ID;
		if (type != expected_type)
			goto err_type;
		if (reg->btf_id != meta->btf_id) {
			verbose(env, "Helper has type %s got %s in R%d\n",
				kernel_type_name(meta->btf_id),
				kernel_type_name(reg->btf_id), regno);

			return -EACCES;
		}
		if (!tnum_is_const(reg->var_off) || reg->var_off.value || reg->off) {
			verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n",
				regno);
			return -EACCES;
		}
	} else if (arg_type == ARG_PTR_TO_SPIN_LOCK) {
		if (meta->func_id == BPF_FUNC_spin_lock) {
			if (process_spin_lock(env, regno, true))
				return -EACCES;
		} else if (meta->func_id == BPF_FUNC_spin_unlock) {
			if (process_spin_lock(env, regno, false))
				return -EACCES;
		} else {
			verbose(env, "verifier internal error\n");
			return -EFAULT;
		}
	} else if (arg_type_is_mem_ptr(arg_type)) {
		expected_type = PTR_TO_STACK;
		/* One exception here. In case function allows for NULL to be
		 * passed in as argument, it's a SCALAR_VALUE type. Final test
		 * happens during stack boundary checking.
		 */
		if (register_is_null(reg) &&
		    arg_type == ARG_PTR_TO_MEM_OR_NULL)
			/* final test in check_stack_boundary() */;
		else if (!type_is_pkt_pointer(type) &&
			 type != PTR_TO_MAP_VALUE &&
			 type != expected_type)
			goto err_type;
		meta->raw_mode = arg_type == ARG_PTR_TO_UNINIT_MEM;
	} else if (arg_type_is_int_ptr(arg_type)) {
		expected_type = PTR_TO_STACK;
		if (!type_is_pkt_pointer(type) &&
		    type != PTR_TO_MAP_VALUE &&
		    type != expected_type)
			goto err_type;
	} else {
		verbose(env, "unsupported arg_type %d\n", arg_type);
		return -EFAULT;
	}

	if (arg_type == ARG_CONST_MAP_PTR) {
		/* bpf_map_xxx(map_ptr) call: remember that map_ptr */
		meta->map_ptr = reg->map_ptr;
	} else if (arg_type == ARG_PTR_TO_MAP_KEY) {
		/* bpf_map_xxx(..., map_ptr, ..., key) call:
		 * check that [key, key + map->key_size) are within
		 * stack limits and initialized
		 */
		if (!meta->map_ptr) {
			/* in function declaration map_ptr must come before
			 * map_key, so that it's verified and known before
			 * we have to check map_key here. Otherwise it means
			 * that kernel subsystem misconfigured verifier
			 */
			verbose(env, "invalid map_ptr to access map->key\n");
			return -EACCES;
		}
		err = check_helper_mem_access(env, regno,
					      meta->map_ptr->key_size, false,
					      NULL);
	} else if (arg_type == ARG_PTR_TO_MAP_VALUE ||
		   (arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL &&
		    !register_is_null(reg)) ||
		   arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE) {
		/* bpf_map_xxx(..., map_ptr, ..., value) call:
		 * check [value, value + map->value_size) validity
		 */
		if (!meta->map_ptr) {
			/* kernel subsystem misconfigured verifier */
			verbose(env, "invalid map_ptr to access map->value\n");
			return -EACCES;
		}
		meta->raw_mode = (arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE);
		err = check_helper_mem_access(env, regno,
					      meta->map_ptr->value_size, false,
					      meta);
	} else if (arg_type_is_mem_size(arg_type)) {
		bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO);

		/* remember the mem_size which may be used later
		 * to refine return values.
		 */
		meta->msize_smax_value = reg->smax_value;
		meta->msize_umax_value = reg->umax_value;

		/* The register is SCALAR_VALUE; the access check
		 * happens using its boundaries.
		 */
		if (!tnum_is_const(reg->var_off))
			/* For unprivileged variable accesses, disable raw
			 * mode so that the program is required to
			 * initialize all the memory that the helper could
			 * just partially fill up.
			 */
			meta = NULL;

		if (reg->smin_value < 0) {
			verbose(env, "R%d min value is negative, either use unsigned or 'var &= const'\n",
				regno);
			return -EACCES;
		}

		if (reg->umin_value == 0) {
			err = check_helper_mem_access(env, regno - 1, 0,
						      zero_size_allowed,
						      meta);
			if (err)
				return err;
		}

		if (reg->umax_value >= BPF_MAX_VAR_SIZ) {
			verbose(env, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
				regno);
			return -EACCES;
		}
		err = check_helper_mem_access(env, regno - 1,
					      reg->umax_value,
					      zero_size_allowed, meta);
		if (!err)
			err = mark_chain_precision(env, regno);
	} else if (arg_type_is_int_ptr(arg_type)) {
		int size = int_ptr_type_to_size(arg_type);

		err = check_helper_mem_access(env, regno, size, false, meta);
		if (err)
			return err;
		err = check_ptr_alignment(env, reg, 0, size, true);
	}

	return err;
err_type:
	verbose(env, "R%d type=%s expected=%s\n", regno,
		reg_type_str[type], reg_type_str[expected_type]);
	return -EACCES;
}

Project: linux
File: verifier.c

static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode,
			   bool is_jmp32)
{
	struct bpf_reg_state reg_lo;
	s64 sval;

	if (__is_pointer_value(false, reg))
		return -1;

	if (is_jmp32) {
		reg_lo = *reg;
		reg = &reg_lo;
		/* For JMP32, only low 32 bits are compared, coerce_reg_to_size
		 * could truncate high bits and update umin/umax according to
		 * information of low bits.
		 */
		coerce_reg_to_size(reg, 4);
		/* smin/smax need special handling. For example, after coerce,
		 * if smin_value is 0x00000000ffffffffLL, the value is -1 when
		 * used as operand to JMP32. It is a negative number from s32's
		 * point of view, while it is a positive number when seen as
		 * s64. The smin/smax are kept as s64, therefore, when used with
		 * JMP32, they need to be transformed into s32, then sign
		 * extended back to s64.
		 *
		 * Also, smin/smax were copied from umin/umax. If umin/umax has
		 * different sign bit, then min/max relationship doesn't
		 * maintain after casting into s32, for this case, set smin/smax
		 * to safest range.
		 */
		if ((reg->umax_value ^ reg->umin_value) &
		    (1ULL << 31)) {
			reg->smin_value = S32_MIN;
			reg->smax_value = S32_MAX;
		}
		reg->smin_value = (s64)(s32)reg->smin_value;
		reg->smax_value = (s64)(s32)reg->smax_value;

		val = (u32)val;
		sval = (s64)(s32)val;
	} else {
		sval = (s64)val;
	}

	switch (opcode) {
	case BPF_JEQ:
		if (tnum_is_const(reg->var_off))
			return !!tnum_equals_const(reg->var_off, val);
		break;
	case BPF_JNE:
		if (tnum_is_const(reg->var_off))
			return !tnum_equals_const(reg->var_off, val);
		break;
	case BPF_JSET:
		if ((~reg->var_off.mask & reg->var_off.value) & val)
			return 1;
		if (!((reg->var_off.mask | reg->var_off.value) & val))
			return 0;
		break;
	case BPF_JGT:
		if (reg->umin_value > val)
			return 1;
		else if (reg->umax_value <= val)
			return 0;
		break;
	case BPF_JSGT:
		if (reg->smin_value > sval)
			return 1;
		else if (reg->smax_value < sval)
			return 0;
		break;
	case BPF_JLT:
		if (reg->umax_value < val)
			return 1;
		else if (reg->umin_value >= val)
			return 0;
		break;
	case BPF_JSLT:
		if (reg->smax_value < sval)
			return 1;
		else if (reg->smin_value >= sval)
			return 0;
		break;
	case BPF_JGE:
		if (reg->umin_value >= val)
			return 1;
		else if (reg->umax_value < val)
			return 0;
		break;
	case BPF_JSGE:
		if (reg->smin_value >= sval)
			return 1;
		else if (reg->smax_value < sval)
			return 0;
		break;
	case BPF_JLE:
		if (reg->umax_value <= val)
			return 1;
		else if (reg->umin_value > val)
			return 0;
		break;
	case BPF_JSLE:
		if (reg->smax_value <= sval)
			return 1;
		else if (reg->smin_value > sval)
			return 0;
		break;
	}

	return -1;
}

Project: linux
File: verifier.c

static int check_reference_leak(struct bpf_verifier_env *env)
{
	struct bpf_func_state *state = cur_func(env);
	int i;

	for (i = 0; i < state->acquired_refs; i++) {
		verbose(env, "Unreleased reference id=%d alloc_insn=%d\n",
			state->refs[i].id, state->refs[i].insn_idx);
	}
	return state->acquired_refs ? -EINVAL : 0;
}

Project: linux
File: verifier.c

static void mark_all_scalars_precise(struct bpf_verifier_env *env,
				     struct bpf_verifier_state *st)
{
	struct bpf_func_state *func;
	struct bpf_reg_state *reg;
	int i, j;

	/* big hammer: mark all scalars precise in this path.
	 * pop_stack may still get !precise scalars.
	 */
	for (; st; st = st->parent)
		for (i = 0; i <= st->curframe; i++) {
			func = st->frame[i];
			for (j = 0; j < BPF_REG_FP; j++) {
				reg = &func->regs[j];
				if (reg->type != SCALAR_VALUE)
					continue;
				reg->precise = true;
			}
			for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
				if (func->stack[j].slot_type[0] != STACK_SPILL)
					continue;
				reg = &func->stack[j].spilled_ptr;
				if (reg->type != SCALAR_VALUE)
					continue;
				reg->precise = true;
			}
		}
}

Project: linux
File: verifier.c

static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data *aux)
{
	return aux->map_key_state & BPF_MAP_KEY_POISON;
}

Project: linux
File: verifier.c

static bool bpf_map_key_unseen(const struct bpf_insn_aux_data *aux)
{
	return !(aux->map_key_state & BPF_MAP_KEY_SEEN);
}

Project: linux
File: verifier.c

static void mark_reg_not_init(struct bpf_verifier_env *env,
			      struct bpf_reg_state *regs, u32 regno)
{
	if (WARN_ON(regno >= MAX_BPF_REG)) {
		verbose(env, "mark_reg_not_init(regs, %u)\n", regno);
		/* Something bad happened, let's kill all regs except FP */
		for (regno = 0; regno < BPF_REG_FP; regno++)
			__mark_reg_not_init(env, regs + regno);
		return;
	}
	__mark_reg_not_init(env, regs + regno);
}

Project: linux
File: verifier.c

static void scalar_min_max_arsh(struct bpf_reg_state *dst_reg,
			        struct bpf_reg_state *src_reg,
				u64 insn_bitness)
{
	u64 umin_val = src_reg->umin_value;

	/* Upon reaching here, src_known is true and
	 * umax_val is equal to umin_val.
	 */
	if (insn_bitness == 32) {
		dst_reg->smin_value = (u32)(((s32)dst_reg->smin_value) >> umin_val);
		dst_reg->smax_value = (u32)(((s32)dst_reg->smax_value) >> umin_val);
	} else {
		dst_reg->smin_value >>= umin_val;
		dst_reg->smax_value >>= umin_val;
	}

	dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val,
					insn_bitness);

	/* blow away the dst_reg umin_value/umax_value and rely on
	 * dst_reg var_off to refine the result.
	 */
	dst_reg->umin_value = 0;
	dst_reg->umax_value = U64_MAX;
	__update_reg_bounds(dst_reg);
}

Project: linux
File: verifier.c

static int check_btf_info(struct bpf_verifier_env *env,
			  const union bpf_attr *attr,
			  union bpf_attr __user *uattr)
{
	struct btf *btf;
	int err;

	if (!attr->func_info_cnt && !attr->line_info_cnt)
		return 0;

	btf = btf_get_by_fd(attr->prog_btf_fd);
	if (IS_ERR(btf))
		return PTR_ERR(btf);
	env->prog->aux->btf = btf;

	err = check_btf_func(env, attr, uattr);
	if (err)
		return err;

	err = check_btf_line(env, attr, uattr);
	if (err)
		return err;

	return 0;
}

Project: linux
File: verifier.c

static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
{
	struct bpf_verifier_state_list *new_sl;
	struct bpf_verifier_state_list *sl, **pprev;
	struct bpf_verifier_state *cur = env->cur_state, *new;
	int i, j, err, states_cnt = 0;
	bool add_new_state = env->test_state_freq ? true : false;

	cur->last_insn_idx = env->prev_insn_idx;
	if (!env->insn_aux_data[insn_idx].prune_point)
		/* this 'insn_idx' instruction wasn't marked, so we will not
		 * be doing state search here
		 */
		return 0;

	/* bpf progs typically have pruning point every 4 instructions
	 * http://vger.kernel.org/bpfconf2019.html#session-1
	 * Do not add new state for future pruning if the verifier hasn't seen
	 * at least 2 jumps and at least 8 instructions.
	 * This heuristics helps decrease 'total_states' and 'peak_states' metric.
	 * In tests that amounts to up to 50% reduction into total verifier
	 * memory consumption and 20% verifier time speedup.
	 */
	if (env->jmps_processed - env->prev_jmps_processed >= 2 &&
	    env->insn_processed - env->prev_insn_processed >= 8)
		add_new_state = true;

	pprev = explored_state(env, insn_idx);
	sl = *pprev;

	clean_live_states(env, insn_idx, cur);

	while (sl) {
		states_cnt++;
		if (sl->state.insn_idx != insn_idx)
			goto next;
		if (sl->state.branches) {
			if (states_maybe_looping(&sl->state, cur) &&
			    states_equal(env, &sl->state, cur)) {
				verbose_linfo(env, insn_idx, "; ");
				verbose(env, "infinite loop detected at insn %d\n", insn_idx);
				return -EINVAL;
			}
			/* if the verifier is processing a loop, avoid adding new state
			 * too often, since different loop iterations have distinct
			 * states and may not help future pruning.
			 * This threshold shouldn't be too low to make sure that
			 * a loop with large bound will be rejected quickly.
			 * The most abusive loop will be:
			 * r1 += 1
			 * if r1 < 1000000 goto pc-2
			 * 1M insn_procssed limit / 100 == 10k peak states.
			 * This threshold shouldn't be too high either, since states
			 * at the end of the loop are likely to be useful in pruning.
			 */
			if (env->jmps_processed - env->prev_jmps_processed < 20 &&
			    env->insn_processed - env->prev_insn_processed < 100)
				add_new_state = false;
			goto miss;
		}
		if (states_equal(env, &sl->state, cur)) {
			sl->hit_cnt++;
			/* reached equivalent register/stack state,
			 * prune the search.
			 * Registers read by the continuation are read by us.
			 * If we have any write marks in env->cur_state, they
			 * will prevent corresponding reads in the continuation
			 * from reaching our parent (an explored_state).  Our
			 * own state will get the read marks recorded, but
			 * they'll be immediately forgotten as we're pruning
			 * this state and will pop a new one.
			 */
			err = propagate_liveness(env, &sl->state, cur);

			/* if previous state reached the exit with precision and
			 * current state is equivalent to it (except precsion marks)
			 * the precision needs to be propagated back in
			 * the current state.
			 */
			err = err ? : push_jmp_history(env, cur);
			err = err ? : propagate_precision(env, &sl->state);
			if (err)
				return err;
			return 1;
		}
miss:
		/* when new state is not going to be added do not increase miss count.
		 * Otherwise several loop iterations will remove the state
		 * recorded earlier. The goal of these heuristics is to have
		 * states from some iterations of the loop (some in the beginning
		 * and some at the end) to help pruning.
		 */
		if (add_new_state)
			sl->miss_cnt++;
		/* heuristic to determine whether this state is beneficial
		 * to keep checking from state equivalence point of view.
		 * Higher numbers increase max_states_per_insn and verification time,
		 * but do not meaningfully decrease insn_processed.
		 */
		if (sl->miss_cnt > sl->hit_cnt * 3 + 3) {
			/* the state is unlikely to be useful. Remove it to
			 * speed up verification
			 */
			*pprev = sl->next;
			if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE) {
				u32 br = sl->state.branches;

				WARN_ONCE(br,
					  "BUG live_done but branches_to_explore %d\n",
					  br);
				free_verifier_state(&sl->state, false);
				kfree(sl);
				env->peak_states--;
			} else {
				/* cannot free this state, since parentage chain may
				 * walk it later. Add it for free_list instead to
				 * be freed at the end of verification
				 */
				sl->next = env->free_list;
				env->free_list = sl;
			}
			sl = *pprev;
			continue;
		}
next:
		pprev = &sl->next;
		sl = *pprev;
	}

	if (env->max_states_per_insn < states_cnt)
		env->max_states_per_insn = states_cnt;

	if (!env->allow_ptr_leaks && states_cnt > BPF_COMPLEXITY_LIMIT_STATES)
		return push_jmp_history(env, cur);

	if (!add_new_state)
		return push_jmp_history(env, cur);

	/* There were no equivalent states, remember the current one.
	 * Technically the current state is not proven to be safe yet,
	 * but it will either reach outer most bpf_exit (which means it's safe)
	 * or it will be rejected. When there are no loops the verifier won't be
	 * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
	 * again on the way to bpf_exit.
	 * When looping the sl->state.branches will be > 0 and this state
	 * will not be considered for equivalence until branches == 0.
	 */
	new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL);
	if (!new_sl)
		return -ENOMEM;
	env->total_states++;
	env->peak_states++;
	env->prev_jmps_processed = env->jmps_processed;
	env->prev_insn_processed = env->insn_processed;

	/* add new state to the head of linked list */
	new = &new_sl->state;
	err = copy_verifier_state(new, cur);
	if (err) {
		free_verifier_state(new, false);
		kfree(new_sl);
		return err;
	}
	new->insn_idx = insn_idx;
	WARN_ONCE(new->branches != 1,
		  "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx);

	cur->parent = new;
	cur->first_insn_idx = insn_idx;
	clear_jmp_history(cur);
	new_sl->next = *explored_state(env, insn_idx);
	*explored_state(env, insn_idx) = new_sl;
	/* connect new state to parentage chain. Current frame needs all
	 * registers connected. Only r6 - r9 of the callers are alive (pushed
	 * to the stack implicitly by JITs) so in callers' frames connect just
	 * r6 - r9 as an optimization. Callers will have r1 - r5 connected to
	 * the state of the call instruction (with WRITTEN set), and r0 comes
	 * from callee with its full parentage chain, anyway.
	 */
	/* clear write marks in current state: the writes we did are not writes
	 * our child did, so they don't screen off its reads from us.
	 * (There are no read marks in current state, because reads always mark
	 * their parent and current state never has children yet.  Only
	 * explored_states can get read marks.)
	 */
	for (j = 0; j <= cur->curframe; j++) {
		for (i = j < cur->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++)
			cur->frame[j]->regs[i].parent = &new->frame[j]->regs[i];
		for (i = 0; i < BPF_REG_FP; i++)
			cur->frame[j]->regs[i].live = REG_LIVE_NONE;
	}

	/* all stack frames are accessible from callee, clear them all */
	for (j = 0; j <= cur->curframe; j++) {
		struct bpf_func_state *frame = cur->frame[j];
		struct bpf_func_state *newframe = new->frame[j];

		for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) {
			frame->stack[i].spilled_ptr.live = REG_LIVE_NONE;
			frame->stack[i].spilled_ptr.parent =
						&newframe->stack[i].spilled_ptr;
		}
	}
	return 0;
}

Project: linux
File: verifier.c

__printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env,
					 u32 insn_off,
					 const char *prefix_fmt, ...)
{
	const struct bpf_line_info *linfo;

	if (!bpf_verifier_log_needed(&env->log))
		return;

	linfo = find_linfo(env, insn_off);
	if (!linfo || linfo == env->prev_linfo)
		return;

	if (prefix_fmt) {
		va_list args;

		va_start(args, prefix_fmt);
		bpf_verifier_vlog(&env->log, prefix_fmt, args);
		va_end(args);
	}

	verbose(env, "%s\n",
		ltrim(btf_name_by_offset(env->prog->aux->btf,
					 linfo->line_off)));

	env->prev_linfo = linfo;
}

Project: linux
File: verifier.c

static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
{
	return reg->type == PTR_TO_MAP_VALUE &&
		map_value_has_spin_lock(reg->map_ptr);
}

Project: linux
File: verifier.c

static bool insn_no_def(struct bpf_insn *insn)
{
	u8 class = BPF_CLASS(insn->code);

	return (class == BPF_JMP || class == BPF_JMP32 ||
		class == BPF_STX || class == BPF_ST);
}

Project: linux
File: verifier.c

static void clean_func_state(struct bpf_verifier_env *env,
			     struct bpf_func_state *st)
{
	enum bpf_reg_liveness live;
	int i, j;

	for (i = 0; i < BPF_REG_FP; i++) {
		live = st->regs[i].live;
		/* liveness must not touch this register anymore */
		st->regs[i].live |= REG_LIVE_DONE;
		if (!(live & REG_LIVE_READ))
			/* since the register is unused, clear its state
			 * to make further comparison simpler
			 */
			__mark_reg_not_init(env, &st->regs[i]);
	}

	for (i = 0; i < st->allocated_stack / BPF_REG_SIZE; i++) {
		live = st->stack[i].spilled_ptr.live;
		/* liveness must not touch this stack slot anymore */
		st->stack[i].spilled_ptr.live |= REG_LIVE_DONE;
		if (!(live & REG_LIVE_READ)) {
			__mark_reg_not_init(env, &st->stack[i].spilled_ptr);
			for (j = 0; j < BPF_REG_SIZE; j++)
				st->stack[i].slot_type[j] = STACK_INVALID;
		}
	}
}

Project: linux
File: verifier.c

static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno)
{
	return cur_regs(env) + regno;
}

Project: linux
File: verifier.c

static void clean_live_states(struct bpf_verifier_env *env, int insn,
			      struct bpf_verifier_state *cur)
{
	struct bpf_verifier_state_list *sl;
	int i;

	sl = *explored_state(env, insn);
	while (sl) {
		if (sl->state.branches)
			goto next;
		if (sl->state.insn_idx != insn ||
		    sl->state.curframe != cur->curframe)
			goto next;
		for (i = 0; i <= cur->curframe; i++)
			if (sl->state.frame[i]->callsite != cur->frame[i]->callsite)
				goto next;
		clean_verifier_state(env, &sl->state);
next:
		sl = sl->next;
	}
}

Project: linux
File: verifier.c

static void mark_ptr_or_null_reg(struct bpf_func_state *state,
				 struct bpf_reg_state *reg, u32 id,
				 bool is_null)
{
	if (reg_type_may_be_null(reg->type) && reg->id == id) {
		/* Old offset (both fixed and variable parts) should
		 * have been known-zero, because we don't allow pointer
		 * arithmetic on pointers that might be NULL.
		 */
		if (WARN_ON_ONCE(reg->smin_value || reg->smax_value ||
				 !tnum_equals_const(reg->var_off, 0) ||
				 reg->off)) {
			__mark_reg_known_zero(reg);
			reg->off = 0;
		}
		if (is_null) {
			reg->type = SCALAR_VALUE;
		} else if (reg->type == PTR_TO_MAP_VALUE_OR_NULL) {
			if (reg->map_ptr->inner_map_meta) {
				reg->type = CONST_PTR_TO_MAP;
				reg->map_ptr = reg->map_ptr->inner_map_meta;
			} else if (reg->map_ptr->map_type ==
				   BPF_MAP_TYPE_XSKMAP) {
				reg->type = PTR_TO_XDP_SOCK;
			} else {
				reg->type = PTR_TO_MAP_VALUE;
			}
		} else if (reg->type == PTR_TO_SOCKET_OR_NULL) {
			reg->type = PTR_TO_SOCKET;
		} else if (reg->type == PTR_TO_SOCK_COMMON_OR_NULL) {
			reg->type = PTR_TO_SOCK_COMMON;
		} else if (reg->type == PTR_TO_TCP_SOCK_OR_NULL) {
			reg->type = PTR_TO_TCP_SOCK;
		}
		if (is_null) {
			/* We don't need id and ref_obj_id from this point
			 * onwards anymore, thus we should better reset it,
			 * so that state pruning has chances to take effect.
			 */
			reg->id = 0;
			reg->ref_obj_id = 0;
		} else if (!reg_may_point_to_spin_lock(reg)) {
			/* For not-NULL ptr, reg->ref_obj_id will be reset
			 * in release_reg_references().
			 *
			 * reg->id is still used by spin_lock ptr. Other
			 * than spin_lock ptr type, reg->id can be reset.
			 */
			reg->id = 0;
		}
	}
}

Project: linux
File: verifier.c

static void reg_combine_min_max(struct bpf_reg_state *true_src,
				struct bpf_reg_state *true_dst,
				struct bpf_reg_state *false_src,
				struct bpf_reg_state *false_dst,
				u8 opcode)
{
	switch (opcode) {
	case BPF_JEQ:
		__reg_combine_min_max(true_src, true_dst);
		break;
	case BPF_JNE:
		__reg_combine_min_max(false_src, false_dst);
		break;
	}
}

Project: linux
File: verifier.c

static u64 bpf_map_key_immediate(const struct bpf_insn_aux_data *aux)
{
	return aux->map_key_state & ~(BPF_MAP_KEY_SEEN | BPF_MAP_KEY_POISON);
}

Project: linux
File: verifier.c

static int do_check_common(struct bpf_verifier_env *env, int subprog)
{
	struct bpf_verifier_state *state;
	struct bpf_reg_state *regs;
	int ret, i;

	env->prev_linfo = NULL;
	env->pass_cnt++;

	state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL);
	if (!state)
		return -ENOMEM;
	state->curframe = 0;
	state->speculative = false;
	state->branches = 1;
	state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL);
	if (!state->frame[0]) {
		kfree(state);
		return -ENOMEM;
	}
	env->cur_state = state;
	init_func_state(env, state->frame[0],
			BPF_MAIN_FUNC /* callsite */,
			0 /* frameno */,
			subprog);

	regs = state->frame[state->curframe]->regs;
	if (subprog || env->prog->type == BPF_PROG_TYPE_EXT) {
		ret = btf_prepare_func_args(env, subprog, regs);
		if (ret)
			goto out;
		for (i = BPF_REG_1; i <= BPF_REG_5; i++) {
			if (regs[i].type == PTR_TO_CTX)
				mark_reg_known_zero(env, regs, i);
			else if (regs[i].type == SCALAR_VALUE)
				mark_reg_unknown(env, regs, i);
		}
	} else {
		/* 1st arg to a function */
		regs[BPF_REG_1].type = PTR_TO_CTX;
		mark_reg_known_zero(env, regs, BPF_REG_1);
		ret = btf_check_func_arg_match(env, subprog, regs);
		if (ret == -EFAULT)
			/* unlikely verifier bug. abort.
			 * ret == 0 and ret < 0 are sadly acceptable for
			 * main() function due to backward compatibility.
			 * Like socket filter program may be written as:
			 * int bpf_prog(struct pt_regs *ctx)
			 * and never dereference that ctx in the program.
			 * 'struct pt_regs' is a type mismatch for socket
			 * filter that should be using 'struct __sk_buff'.
			 */
			goto out;
	}

	ret = do_check(env);
out:
	/* check for NULL is necessary, since cur_state can be freed inside
	 * do_check() under memory pressure.
	 */
	if (env->cur_state) {
		free_verifier_state(env->cur_state, true);
		env->cur_state = NULL;
	}
	while (!pop_stack(env, NULL, NULL));
	free_states(env);
	if (ret)
		/* clean aux data in case subprog was rejected */
		sanitize_insn_aux_data(env);
	return ret;
}

Project: linux
File: verifier.c

static void scalar_min_max_lsh(struct bpf_reg_state *dst_reg,
			       struct bpf_reg_state *src_reg)
{
	u64 umax_val = src_reg->umax_value;
	u64 umin_val = src_reg->umin_value;

	/* We lose all sign bit information (except what we can pick
	 * up from var_off)
	 */
	dst_reg->smin_value = S64_MIN;
	dst_reg->smax_value = S64_MAX;
	/* If we might shift our top bit out, then we know nothing */
	if (dst_reg->umax_value > 1ULL << (63 - umax_val)) {
		dst_reg->umin_value = 0;
		dst_reg->umax_value = U64_MAX;
	} else {
		dst_reg->umin_value <<= umin_val;
		dst_reg->umax_value <<= umax_val;
	}
	dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val);
	/* We may learn something more from the var_off */
	__update_reg_bounds(dst_reg);
}

Project: linux
File: verifier.c

static int check_reg_arg(struct bpf_verifier_env *env, u32 regno,
			 enum reg_arg_type t)
{
	struct bpf_verifier_state *vstate = env->cur_state;
	struct bpf_func_state *state = vstate->frame[vstate->curframe];
	struct bpf_insn *insn = env->prog->insnsi + env->insn_idx;
	struct bpf_reg_state *reg, *regs = state->regs;
	bool rw64;

	if (regno >= MAX_BPF_REG) {
		verbose(env, "R%d is invalid\n", regno);
		return -EINVAL;
	}

	reg = &regs[regno];
	rw64 = is_reg64(env, insn, regno, reg, t);
	if (t == SRC_OP) {
		/* check whether register used as source operand can be read */
		if (reg->type == NOT_INIT) {
			verbose(env, "R%d !read_ok\n", regno);
			return -EACCES;
		}
		/* We don't need to worry about FP liveness because it's read-only */
		if (regno == BPF_REG_FP)
			return 0;

		if (rw64)
			mark_insn_zext(env, reg);

		return mark_reg_read(env, reg, reg->parent,
				     rw64 ? REG_LIVE_READ64 : REG_LIVE_READ32);
	} else {
		/* check whether register used as dest operand can be written to */
		if (regno == BPF_REG_FP) {
			verbose(env, "frame pointer is read only\n");
			return -EACCES;
		}
		reg->live |= REG_LIVE_WRITTEN;
		reg->subreg_def = rw64 ? DEF_NOT_SUBREG : env->insn_idx + 1;
		if (t == DST_OP)
			mark_reg_unknown(env, regs, regno);
	}
	return 0;
}

Project: linux
File: verifier.c

static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
			   int *insn_idx)
{
	struct bpf_verifier_state *state = env->cur_state;
	struct bpf_func_info_aux *func_info_aux;
	struct bpf_func_state *caller, *callee;
	int i, err, subprog, target_insn;
	bool is_global = false;

	if (state->curframe + 1 >= MAX_CALL_FRAMES) {
		verbose(env, "the call stack of %d frames is too deep\n",
			state->curframe + 2);
		return -E2BIG;
	}

	target_insn = *insn_idx + insn->imm;
	subprog = find_subprog(env, target_insn + 1);
	if (subprog < 0) {
		verbose(env, "verifier bug. No program starts at insn %d\n",
			target_insn + 1);
		return -EFAULT;
	}

	caller = state->frame[state->curframe];
	if (state->frame[state->curframe + 1]) {
		verbose(env, "verifier bug. Frame %d already allocated\n",
			state->curframe + 1);
		return -EFAULT;
	}

	func_info_aux = env->prog->aux->func_info_aux;
	if (func_info_aux)
		is_global = func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
	err = btf_check_func_arg_match(env, subprog, caller->regs);
	if (err == -EFAULT)
		return err;
	if (is_global) {
		if (err) {
			verbose(env, "Caller passes invalid args into func#%d\n",
				subprog);
			return err;
		} else {
			if (env->log.level & BPF_LOG_LEVEL)
				verbose(env,
					"Func#%d is global and valid. Skipping.\n",
					subprog);
			clear_caller_saved_regs(env, caller->regs);

			/* All global functions return SCALAR_VALUE */
			mark_reg_unknown(env, caller->regs, BPF_REG_0);

			/* continue with next insn after call */
			return 0;
		}
	}

	callee = kzalloc(sizeof(*callee), GFP_KERNEL);
	if (!callee)
		return -ENOMEM;
	state->frame[state->curframe + 1] = callee;

	/* callee cannot access r0, r6 - r9 for reading and has to write
	 * into its own stack before reading from it.
	 * callee can read/write into caller's stack
	 */
	init_func_state(env, callee,
			/* remember the callsite, it will be used by bpf_exit */
			*insn_idx /* callsite */,
			state->curframe + 1 /* frameno within this callchain */,
			subprog /* subprog number within this prog */);

	/* Transfer references to the callee */
	err = transfer_reference_state(callee, caller);
	if (err)
		return err;

	/* copy r1 - r5 args that callee can access.  The copy includes parent
	 * pointers, which connects us up to the liveness chain
	 */
	for (i = BPF_REG_1; i <= BPF_REG_5; i++)
		callee->regs[i] = caller->regs[i];

	clear_caller_saved_regs(env, caller->regs);

	/* only increment it after check_reg_arg() finished */
	state->curframe++;

	/* and go analyze first insn of the callee */
	*insn_idx = target_insn;

	if (env->log.level & BPF_LOG_LEVEL) {
		verbose(env, "caller:\n");
		print_verifier_state(env, caller);
		verbose(env, "callee:\n");
		print_verifier_state(env, callee);
	}
	return 0;
}

Project: linux
File: verifier.c

static int __mark_chain_precision(struct bpf_verifier_env *env, int regno,
				  int spi)
{
	struct bpf_verifier_state *st = env->cur_state;
	int first_idx = st->first_insn_idx;
	int last_idx = env->insn_idx;
	struct bpf_func_state *func;
	struct bpf_reg_state *reg;
	u32 reg_mask = regno >= 0 ? 1u << regno : 0;
	u64 stack_mask = spi >= 0 ? 1ull << spi : 0;
	bool skip_first = true;
	bool new_marks = false;
	int i, err;

	if (!env->allow_ptr_leaks)
		/* backtracking is root only for now */
		return 0;

	func = st->frame[st->curframe];
	if (regno >= 0) {
		reg = &func->regs[regno];
		if (reg->type != SCALAR_VALUE) {
			WARN_ONCE(1, "backtracing misuse");
			return -EFAULT;
		}
		if (!reg->precise)
			new_marks = true;
		else
			reg_mask = 0;
		reg->precise = true;
	}

	while (spi >= 0) {
		if (func->stack[spi].slot_type[0] != STACK_SPILL) {
			stack_mask = 0;
			break;
		}
		reg = &func->stack[spi].spilled_ptr;
		if (reg->type != SCALAR_VALUE) {
			stack_mask = 0;
			break;
		}
		if (!reg->precise)
			new_marks = true;
		else
			stack_mask = 0;
		reg->precise = true;
		break;
	}

	if (!new_marks)
		return 0;
	if (!reg_mask && !stack_mask)
		return 0;
	for (;;) {
		DECLARE_BITMAP(mask, 64);
		u32 history = st->jmp_history_cnt;

		if (env->log.level & BPF_LOG_LEVEL)
			verbose(env, "last_idx %d first_idx %d\n", last_idx, first_idx);
		for (i = last_idx;;) {
			if (skip_first) {
				err = 0;
				skip_first = false;
			} else {
				err = backtrack_insn(env, i, &reg_mask, &stack_mask);
			}
			if (err == -ENOTSUPP) {
				mark_all_scalars_precise(env, st);
				return 0;
			} else if (err) {
				return err;
			}
			if (!reg_mask && !stack_mask)
				/* Found assignment(s) into tracked register in this state.
				 * Since this state is already marked, just return.
				 * Nothing to be tracked further in the parent state.
				 */
				return 0;
			if (i == first_idx)
				break;
			i = get_prev_insn_idx(st, i, &history);
			if (i >= env->prog->len) {
				/* This can happen if backtracking reached insn 0
				 * and there are still reg_mask or stack_mask
				 * to backtrack.
				 * It means the backtracking missed the spot where
				 * particular register was initialized with a constant.
				 */
				verbose(env, "BUG backtracking idx %d\n", i);
				WARN_ONCE(1, "verifier backtracking bug");
				return -EFAULT;
			}
		}
		st = st->parent;
		if (!st)
			break;

		new_marks = false;
		func = st->frame[st->curframe];
		bitmap_from_u64(mask, reg_mask);
		for_each_set_bit(i, mask, 32) {
			reg = &func->regs[i];
			if (reg->type != SCALAR_VALUE) {
				reg_mask &= ~(1u << i);
				continue;
			}
			if (!reg->precise)
				new_marks = true;
			reg->precise = true;
		}

		bitmap_from_u64(mask, stack_mask);
		for_each_set_bit(i, mask, 64) {
			if (i >= func->allocated_stack / BPF_REG_SIZE) {
				/* the sequence of instructions:
				 * 2: (bf) r3 = r10
				 * 3: (7b) *(u64 *)(r3 -8) = r0
				 * 4: (79) r4 = *(u64 *)(r10 -8)
				 * doesn't contain jmps. It's backtracked
				 * as a single block.
				 * During backtracking insn 3 is not recognized as
				 * stack access, so at the end of backtracking
				 * stack slot fp-8 is still marked in stack_mask.
				 * However the parent state may not have accessed
				 * fp-8 and it's "unallocated" stack space.
				 * In such case fallback to conservative.
				 */
				mark_all_scalars_precise(env, st);
				return 0;
			}

			if (func->stack[i].slot_type[0] != STACK_SPILL) {
				stack_mask &= ~(1ull << i);
				continue;
			}
			reg = &func->stack[i].spilled_ptr;
			if (reg->type != SCALAR_VALUE) {
				stack_mask &= ~(1ull << i);
				continue;
			}
			if (!reg->precise)
				new_marks = true;
			reg->precise = true;
		}
		if (env->log.level & BPF_LOG_LEVEL) {
			print_verifier_state(env, func);
			verbose(env, "parent %s regs=%x stack=%llx marks\n",
				new_marks ? "didn't have" : "already had",
				reg_mask, stack_mask);
		}

		if (!reg_mask && !stack_mask)
			break;
		if (!new_marks)
			break;

		last_idx = st->last_insn_idx;
		first_idx = st->first_insn_idx;
	}
	return 0;
}

Project: linux
File: verifier.c

static bool insn_is_cond_jump(u8 code)
{
	u8 op;

	if (BPF_CLASS(code) == BPF_JMP32)
		return true;

	if (BPF_CLASS(code) != BPF_JMP)
		return false;

	op = BPF_OP(code);
	return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL;
}

Project: linux
File: verifier.c

static int opt_remove_nops(struct bpf_verifier_env *env)
{
	const struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
	struct bpf_insn *insn = env->prog->insnsi;
	int insn_cnt = env->prog->len;
	int i, err;

	for (i = 0; i < insn_cnt; i++) {
		if (memcmp(&insn[i], &ja, sizeof(ja)))
			continue;

		err = verifier_remove_insns(env, i, 1);
		if (err)
			return err;
		insn_cnt--;
		i--;
	}

	return 0;
}

Project: linux
File: verifier.c

static bool type_is_sk_pointer(enum bpf_reg_type type)
{
	return type == PTR_TO_SOCKET ||
		type == PTR_TO_SOCK_COMMON ||
		type == PTR_TO_TCP_SOCK ||
		type == PTR_TO_XDP_SOCK;
}

Project: linux
File: verifier.c

static void __mark_reg_known_zero(struct bpf_reg_state *reg)
{
	__mark_reg_known(reg, 0);
}

Project: linux
File: verifier.c

static void __reg_bound_offset32(struct bpf_reg_state *reg)
{
	u64 mask = 0xffffFFFF;
	struct tnum range = tnum_range(reg->umin_value & mask,
				       reg->umax_value & mask);
	struct tnum lo32 = tnum_cast(reg->var_off, 4);
	struct tnum hi32 = tnum_lshift(tnum_rshift(reg->var_off, 32), 32);

	reg->var_off = tnum_or(hi32, tnum_intersect(lo32, range));
}

Project: linux
File: verifier.c

static int check_map_access(struct bpf_verifier_env *env, u32 regno,
			    int off, int size, bool zero_size_allowed)
{
	struct bpf_verifier_state *vstate = env->cur_state;
	struct bpf_func_state *state = vstate->frame[vstate->curframe];
	struct bpf_reg_state *reg = &state->regs[regno];
	int err;

	/* We may have adjusted the register to this map value, so we
	 * need to try adding each of min_value and max_value to off
	 * to make sure our theoretical access will be safe.
	 */
	if (env->log.level & BPF_LOG_LEVEL)
		print_verifier_state(env, state);

	/* The minimum value is only important with signed
	 * comparisons where we can't assume the floor of a
	 * value is 0.  If we are using signed variables for our
	 * index'es we need to make sure that whatever we use
	 * will have a set floor within our range.
	 */
	if (reg->smin_value < 0 &&
	    (reg->smin_value == S64_MIN ||
	     (off + reg->smin_value != (s64)(s32)(off + reg->smin_value)) ||
	      reg->smin_value + off < 0)) {
		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
			regno);
		return -EACCES;
	}
	err = __check_map_access(env, regno, reg->smin_value + off, size,
				 zero_size_allowed);
	if (err) {
		verbose(env, "R%d min value is outside of the array range\n",
			regno);
		return err;
	}

	/* If we haven't set a max value then we need to bail since we can't be
	 * sure we won't do bad things.
	 * If reg->umax_value + off could overflow, treat that as unbounded too.
	 */
	if (reg->umax_value >= BPF_MAX_VAR_OFF) {
		verbose(env, "R%d unbounded memory access, make sure to bounds check any array access into a map\n",
			regno);
		return -EACCES;
	}
	err = __check_map_access(env, regno, reg->umax_value + off, size,
				 zero_size_allowed);
	if (err)
		verbose(env, "R%d max value is outside of the array range\n",
			regno);

	if (map_value_has_spin_lock(reg->map_ptr)) {
		u32 lock = reg->map_ptr->spin_lock_off;

		/* if any part of struct bpf_spin_lock can be touched by
		 * load/store reject this program.
		 * To check that [x1, x2) overlaps with [y1, y2)
		 * it is sufficient to check x1 < y2 && y1 < x2.
		 */
		if (reg->smin_value + off < lock + sizeof(struct bpf_spin_lock) &&
		     lock < reg->umax_value + off + size) {
			verbose(env, "bpf_spin_lock cannot be accessed directly by load/store\n");
			return -EACCES;
		}
	}
	return err;
}

Project: linux
File: verifier.c

static int push_jmp_history(struct bpf_verifier_env *env,
			    struct bpf_verifier_state *cur)
{
	u32 cnt = cur->jmp_history_cnt;
	struct bpf_idx_pair *p;

	cnt++;
	p = krealloc(cur->jmp_history, cnt * sizeof(*p), GFP_USER);
	if (!p)
		return -ENOMEM;
	p[cnt - 1].idx = env->insn_idx;
	p[cnt - 1].prev_idx = env->prev_insn_idx;
	cur->jmp_history = p;
	cur->jmp_history_cnt = cnt;
	return 0;
}

Project: linux
File: verifier.c

static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
				int access_size, bool zero_size_allowed,
				struct bpf_call_arg_meta *meta)
{
	struct bpf_reg_state *reg = reg_state(env, regno);
	struct bpf_func_state *state = func(env, reg);
	int err, min_off, max_off, i, j, slot, spi;

	if (reg->type != PTR_TO_STACK) {
		/* Allow zero-byte read from NULL, regardless of pointer type */
		if (zero_size_allowed && access_size == 0 &&
		    register_is_null(reg))
			return 0;

		verbose(env, "R%d type=%s expected=%s\n", regno,
			reg_type_str[reg->type],
			reg_type_str[PTR_TO_STACK]);
		return -EACCES;
	}

	if (tnum_is_const(reg->var_off)) {
		min_off = max_off = reg->var_off.value + reg->off;
		err = __check_stack_boundary(env, regno, min_off, access_size,
					     zero_size_allowed);
		if (err)
			return err;
	} else {
		/* Variable offset is prohibited for unprivileged mode for
		 * simplicity since it requires corresponding support in
		 * Spectre masking for stack ALU.
		 * See also retrieve_ptr_limit().
		 */
		if (!env->allow_ptr_leaks) {
			char tn_buf[48];

			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
			verbose(env, "R%d indirect variable offset stack access prohibited for !root, var_off=%s\n",
				regno, tn_buf);
			return -EACCES;
		}
		/* Only initialized buffer on stack is allowed to be accessed
		 * with variable offset. With uninitialized buffer it's hard to
		 * guarantee that whole memory is marked as initialized on
		 * helper return since specific bounds are unknown what may
		 * cause uninitialized stack leaking.
		 */
		if (meta && meta->raw_mode)
			meta = NULL;

		if (reg->smax_value >= BPF_MAX_VAR_OFF ||
		    reg->smax_value <= -BPF_MAX_VAR_OFF) {
			verbose(env, "R%d unbounded indirect variable offset stack access\n",
				regno);
			return -EACCES;
		}
		min_off = reg->smin_value + reg->off;
		max_off = reg->smax_value + reg->off;
		err = __check_stack_boundary(env, regno, min_off, access_size,
					     zero_size_allowed);
		if (err) {
			verbose(env, "R%d min value is outside of stack bound\n",
				regno);
			return err;
		}
		err = __check_stack_boundary(env, regno, max_off, access_size,
					     zero_size_allowed);
		if (err) {
			verbose(env, "R%d max value is outside of stack bound\n",
				regno);
			return err;
		}
	}

	if (meta && meta->raw_mode) {
		meta->access_size = access_size;
		meta->regno = regno;
		return 0;
	}

	for (i = min_off; i < max_off + access_size; i++) {
		u8 *stype;

		slot = -i - 1;
		spi = slot / BPF_REG_SIZE;
		if (state->allocated_stack <= slot)
			goto err;
		stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
		if (*stype == STACK_MISC)
			goto mark;
		if (*stype == STACK_ZERO) {
			/* helper can write anything into the stack */
			*stype = STACK_MISC;
			goto mark;
		}
		if (state->stack[spi].slot_type[0] == STACK_SPILL &&
		    state->stack[spi].spilled_ptr.type == SCALAR_VALUE) {
			__mark_reg_unknown(env, &state->stack[spi].spilled_ptr);
			for (j = 0; j < BPF_REG_SIZE; j++)
				state->stack[spi].slot_type[j] = STACK_MISC;
			goto mark;
		}

err:
		if (tnum_is_const(reg->var_off)) {
			verbose(env, "invalid indirect read from stack off %d+%d size %d\n",
				min_off, i - min_off, access_size);
		} else {
			char tn_buf[48];

			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
			verbose(env, "invalid indirect read from stack var_off %s+%d size %d\n",
				tn_buf, i - min_off, access_size);
		}
		return -EACCES;
mark:
		/* reading any byte out of 8-byte 'spill_slot' will cause
		 * the whole slot to be marked as 'read'
		 */
		mark_reg_read(env, &state->stack[spi].spilled_ptr,
			      state->stack[spi].spilled_ptr.parent,
			      REG_LIVE_READ64);
	}
	return update_stack_depth(env, state, min_off);
}

Project: linux
File: verifier.c

static int sanitize_val_alu(struct bpf_verifier_env *env,
			    struct bpf_insn *insn)
{
	struct bpf_insn_aux_data *aux = cur_aux(env);

	if (can_skip_alu_sanitation(env, insn))
		return 0;

	return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0);
}

Project: linux
File: verifier.c

static void scalar_min_max_add(struct bpf_reg_state *dst_reg,
			       struct bpf_reg_state *src_reg)
{
	s64 smin_val = src_reg->smin_value;
	s64 smax_val = src_reg->smax_value;
	u64 umin_val = src_reg->umin_value;
	u64 umax_val = src_reg->umax_value;

	if (signed_add_overflows(dst_reg->smin_value, smin_val) ||
	    signed_add_overflows(dst_reg->smax_value, smax_val)) {
		dst_reg->smin_value = S64_MIN;
		dst_reg->smax_value = S64_MAX;
	} else {
		dst_reg->smin_value += smin_val;
		dst_reg->smax_value += smax_val;
	}
	if (dst_reg->umin_value + umin_val < umin_val ||
	    dst_reg->umax_value + umax_val < umax_val) {
		dst_reg->umin_value = 0;
		dst_reg->umax_value = U64_MAX;
	} else {
		dst_reg->umin_value += umin_val;
		dst_reg->umax_value += umax_val;
	}
	dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg->var_off);
}

Project: linux
File: verifier.c

static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
{
	struct bpf_insn_aux_data *aux = cur_aux(env);
	struct bpf_reg_state *regs = cur_regs(env);
	struct bpf_map *map;
	int err;

	if (BPF_SIZE(insn->code) != BPF_DW) {
		verbose(env, "invalid BPF_LD_IMM insn\n");
		return -EINVAL;
	}
	if (insn->off != 0) {
		verbose(env, "BPF_LD_IMM64 uses reserved fields\n");
		return -EINVAL;
	}

	err = check_reg_arg(env, insn->dst_reg, DST_OP);
	if (err)
		return err;

	if (insn->src_reg == 0) {
		u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;

		regs[insn->dst_reg].type = SCALAR_VALUE;
		__mark_reg_known(&regs[insn->dst_reg], imm);
		return 0;
	}

	map = env->used_maps[aux->map_index];
	mark_reg_known_zero(env, regs, insn->dst_reg);
	regs[insn->dst_reg].map_ptr = map;

	if (insn->src_reg == BPF_PSEUDO_MAP_VALUE) {
		regs[insn->dst_reg].type = PTR_TO_MAP_VALUE;
		regs[insn->dst_reg].off = aux->map_off;
		if (map_value_has_spin_lock(map))
			regs[insn->dst_reg].id = ++env->id_gen;
	} else if (insn->src_reg == BPF_PSEUDO_MAP_FD) {
		regs[insn->dst_reg].type = CONST_PTR_TO_MAP;
	} else {
		verbose(env, "bpf verifier is misconfigured\n");
		return -EINVAL;
	}

	return 0;
}

Project: linux
File: verifier.c

static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux,
				       u32 alu_state, u32 alu_limit)
{
	/* If we arrived here from different branches with different
	 * state or limits to sanitize, then this won't work.
	 */
	if (aux->alu_state &&
	    (aux->alu_state != alu_state ||
	     aux->alu_limit != alu_limit))
		return -EACCES;

	/* Corresponding fixup done in fixup_bpf_calls(). */
	aux->alu_state = alu_state;
	aux->alu_limit = alu_limit;
	return 0;
}

Project: linux
File: verifier.c

static int check_stack_read(struct bpf_verifier_env *env,
			    struct bpf_func_state *reg_state /* func where register points to */,
			    int off, int size, int value_regno)
{
	struct bpf_verifier_state *vstate = env->cur_state;
	struct bpf_func_state *state = vstate->frame[vstate->curframe];
	int i, slot = -off - 1, spi = slot / BPF_REG_SIZE;
	struct bpf_reg_state *reg;
	u8 *stype;

	if (reg_state->allocated_stack <= slot) {
		verbose(env, "invalid read from stack off %d+0 size %d\n",
			off, size);
		return -EACCES;
	}
	stype = reg_state->stack[spi].slot_type;
	reg = &reg_state->stack[spi].spilled_ptr;

	if (stype[0] == STACK_SPILL) {
		if (size != BPF_REG_SIZE) {
			if (reg->type != SCALAR_VALUE) {
				verbose_linfo(env, env->insn_idx, "; ");
				verbose(env, "invalid size of register fill\n");
				return -EACCES;
			}
			if (value_regno >= 0) {
				mark_reg_unknown(env, state->regs, value_regno);
				state->regs[value_regno].live |= REG_LIVE_WRITTEN;
			}
			mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
			return 0;
		}
		for (i = 1; i < BPF_REG_SIZE; i++) {
			if (stype[(slot - i) % BPF_REG_SIZE] != STACK_SPILL) {
				verbose(env, "corrupted spill memory\n");
				return -EACCES;
			}
		}

		if (value_regno >= 0) {
			/* restore register state from stack */
			state->regs[value_regno] = *reg;
			/* mark reg as written since spilled pointer state likely
			 * has its liveness marks cleared by is_state_visited()
			 * which resets stack/reg liveness for state transitions
			 */
			state->regs[value_regno].live |= REG_LIVE_WRITTEN;
		}
		mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
	} else {
		int zeros = 0;

		for (i = 0; i < size; i++) {
			if (stype[(slot - i) % BPF_REG_SIZE] == STACK_MISC)
				continue;
			if (stype[(slot - i) % BPF_REG_SIZE] == STACK_ZERO) {
				zeros++;
				continue;
			}
			verbose(env, "invalid read from stack off %d+%d size %d\n",
				off, i, size);
			return -EACCES;
		}
		mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
		if (value_regno >= 0) {
			if (zeros == size) {
				/* any size read into register is zero extended,
				 * so the whole register == const_zero
				 */
				__mark_reg_const_zero(&state->regs[value_regno]);
				/* backtracking doesn't support STACK_ZERO yet,
				 * so mark it precise here, so that later
				 * backtracking can stop here.
				 * Backtracking may not need this if this register
				 * doesn't participate in pointer adjustment.
				 * Forward propagation of precise flag is not
				 * necessary either. This mark is only to stop
				 * backtracking. Any register that contributed
				 * to const 0 was marked precise before spill.
				 */
				state->regs[value_regno].precise = true;
			} else {
				/* have read misc data from the stack */
				mark_reg_unknown(env, state->regs, value_regno);
			}
			state->regs[value_regno].live |= REG_LIVE_WRITTEN;
		}
	}
	return 0;
}

Project: linux
File: verifier.c

static int check_map_prealloc(struct bpf_map *map)
{
	return (map->map_type != BPF_MAP_TYPE_HASH &&
		map->map_type != BPF_MAP_TYPE_PERCPU_HASH &&
		map->map_type != BPF_MAP_TYPE_HASH_OF_MAPS) ||
		!(map->map_flags & BPF_F_NO_PREALLOC);
}

Project: linux
File: verifier.c

static int __check_packet_access(struct bpf_verifier_env *env, u32 regno,
				 int off, int size, bool zero_size_allowed)
{
	struct bpf_reg_state *regs = cur_regs(env);
	struct bpf_reg_state *reg = &regs[regno];

	if (off < 0 || size < 0 || (size == 0 && !zero_size_allowed) ||
	    (u64)off + size > reg->range) {
		verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
			off, size, regno, reg->id, reg->off, reg->range);
		return -EACCES;
	}
	return 0;
}

Project: linux
File: verifier.c

static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux,
			      const struct bpf_map *map, bool unpriv)
{
	BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV);
	unpriv |= bpf_map_ptr_unpriv(aux);
	aux->map_ptr_state = (unsigned long)map |
			     (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL);
}

Project: linux
File: verifier.c

__printf(2, 3) void bpf_log(struct bpf_verifier_log *log,
			    const char *fmt, ...)
{
	va_list args;

	if (!bpf_verifier_log_needed(log))
		return;

	va_start(args, fmt);
	bpf_verifier_vlog(log, fmt, args);
	va_end(args);
}

Project: linux
File: verifier.c

static int check_map_func_compatibility(struct bpf_verifier_env *env,
					struct bpf_map *map, int func_id)
{
	if (!map)
		return 0;

	/* We need a two way check, first is from map perspective ... */
	switch (map->map_type) {
	case BPF_MAP_TYPE_PROG_ARRAY:
		if (func_id != BPF_FUNC_tail_call)
			goto error;
		break;
	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
		if (func_id != BPF_FUNC_perf_event_read &&
		    func_id != BPF_FUNC_perf_event_output &&
		    func_id != BPF_FUNC_skb_output &&
		    func_id != BPF_FUNC_perf_event_read_value &&
		    func_id != BPF_FUNC_xdp_output)
			goto error;
		break;
	case BPF_MAP_TYPE_STACK_TRACE:
		if (func_id != BPF_FUNC_get_stackid)
			goto error;
		break;
	case BPF_MAP_TYPE_CGROUP_ARRAY:
		if (func_id != BPF_FUNC_skb_under_cgroup &&
		    func_id != BPF_FUNC_current_task_under_cgroup)
			goto error;
		break;
	case BPF_MAP_TYPE_CGROUP_STORAGE:
	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
		if (func_id != BPF_FUNC_get_local_storage)
			goto error;
		break;
	case BPF_MAP_TYPE_DEVMAP:
	case BPF_MAP_TYPE_DEVMAP_HASH:
		if (func_id != BPF_FUNC_redirect_map &&
		    func_id != BPF_FUNC_map_lookup_elem)
			goto error;
		break;
	/* Restrict bpf side of cpumap and xskmap, open when use-cases
	 * appear.
	 */
	case BPF_MAP_TYPE_CPUMAP:
		if (func_id != BPF_FUNC_redirect_map)
			goto error;
		break;
	case BPF_MAP_TYPE_XSKMAP:
		if (func_id != BPF_FUNC_redirect_map &&
		    func_id != BPF_FUNC_map_lookup_elem)
			goto error;
		break;
	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
	case BPF_MAP_TYPE_HASH_OF_MAPS:
		if (func_id != BPF_FUNC_map_lookup_elem)
			goto error;
		break;
	case BPF_MAP_TYPE_SOCKMAP:
		if (func_id != BPF_FUNC_sk_redirect_map &&
		    func_id != BPF_FUNC_sock_map_update &&
		    func_id != BPF_FUNC_map_delete_elem &&
		    func_id != BPF_FUNC_msg_redirect_map &&
		    func_id != BPF_FUNC_sk_select_reuseport)
			goto error;
		break;
	case BPF_MAP_TYPE_SOCKHASH:
		if (func_id != BPF_FUNC_sk_redirect_hash &&
		    func_id != BPF_FUNC_sock_hash_update &&
		    func_id != BPF_FUNC_map_delete_elem &&
		    func_id != BPF_FUNC_msg_redirect_hash &&
		    func_id != BPF_FUNC_sk_select_reuseport)
			goto error;
		break;
	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
		if (func_id != BPF_FUNC_sk_select_reuseport)
			goto error;
		break;
	case BPF_MAP_TYPE_QUEUE:
	case BPF_MAP_TYPE_STACK:
		if (func_id != BPF_FUNC_map_peek_elem &&
		    func_id != BPF_FUNC_map_pop_elem &&
		    func_id != BPF_FUNC_map_push_elem)
			goto error;
		break;
	case BPF_MAP_TYPE_SK_STORAGE:
		if (func_id != BPF_FUNC_sk_storage_get &&
		    func_id != BPF_FUNC_sk_storage_delete)
			goto error;
		break;
	default:
		break;
	}

	/* ... and second from the function itself. */
	switch (func_id) {
	case BPF_FUNC_tail_call:
		if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
			goto error;
		if (env->subprog_cnt > 1) {
			verbose(env, "tail_calls are not allowed in programs with bpf-to-bpf calls\n");
			return -EINVAL;
		}
		break;
	case BPF_FUNC_perf_event_read:
	case BPF_FUNC_perf_event_output:
	case BPF_FUNC_perf_event_read_value:
	case BPF_FUNC_skb_output:
	case BPF_FUNC_xdp_output:
		if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
			goto error;
		break;
	case BPF_FUNC_get_stackid:
		if (map->map_type != BPF_MAP_TYPE_STACK_TRACE)
			goto error;
		break;
	case BPF_FUNC_current_task_under_cgroup:
	case BPF_FUNC_skb_under_cgroup:
		if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY)
			goto error;
		break;
	case BPF_FUNC_redirect_map:
		if (map->map_type != BPF_MAP_TYPE_DEVMAP &&
		    map->map_type != BPF_MAP_TYPE_DEVMAP_HASH &&
		    map->map_type != BPF_MAP_TYPE_CPUMAP &&
		    map->map_type != BPF_MAP_TYPE_XSKMAP)
			goto error;
		break;
	case BPF_FUNC_sk_redirect_map:
	case BPF_FUNC_msg_redirect_map:
	case BPF_FUNC_sock_map_update:
		if (map->map_type != BPF_MAP_TYPE_SOCKMAP)
			goto error;
		break;
	case BPF_FUNC_sk_redirect_hash:
	case BPF_FUNC_msg_redirect_hash:
	case BPF_FUNC_sock_hash_update:
		if (map->map_type != BPF_MAP_TYPE_SOCKHASH)
			goto error;
		break;
	case BPF_FUNC_get_local_storage:
		if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
		    map->map_type != BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
			goto error;
		break;
	case BPF_FUNC_sk_select_reuseport:
		if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY &&
		    map->map_type != BPF_MAP_TYPE_SOCKMAP &&
		    map->map_type != BPF_MAP_TYPE_SOCKHASH)
			goto error;
		break;
	case BPF_FUNC_map_peek_elem:
	case BPF_FUNC_map_pop_elem:
	case BPF_FUNC_map_push_elem:
		if (map->map_type != BPF_MAP_TYPE_QUEUE &&
		    map->map_type != BPF_MAP_TYPE_STACK)
			goto error;
		break;
	case BPF_FUNC_sk_storage_get:
	case BPF_FUNC_sk_storage_delete:
		if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
			goto error;
		break;
	default:
		break;
	}

	return 0;
error:
	verbose(env, "cannot pass map_type %d into func %s#%d\n",
		map->map_type, func_id_name(func_id), func_id);
	return -EINVAL;
}

Project: linux
File: verifier.c

static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env,
				    const struct bpf_insn *insn)
{
	return env->allow_ptr_leaks || BPF_SRC(insn->code) == BPF_K;
}

Project: linux
File: verifier.c

static int process_spin_lock(struct bpf_verifier_env *env, int regno,
			     bool is_lock)
{
	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
	struct bpf_verifier_state *cur = env->cur_state;
	bool is_const = tnum_is_const(reg->var_off);
	struct bpf_map *map = reg->map_ptr;
	u64 val = reg->var_off.value;

	if (reg->type != PTR_TO_MAP_VALUE) {
		verbose(env, "R%d is not a pointer to map_value\n", regno);
		return -EINVAL;
	}
	if (!is_const) {
		verbose(env,
			"R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n",
			regno);
		return -EINVAL;
	}
	if (!map->btf) {
		verbose(env,
			"map '%s' has to have BTF in order to use bpf_spin_lock\n",
			map->name);
		return -EINVAL;
	}
	if (!map_value_has_spin_lock(map)) {
		if (map->spin_lock_off == -E2BIG)
			verbose(env,
				"map '%s' has more than one 'struct bpf_spin_lock'\n",
				map->name);
		else if (map->spin_lock_off == -ENOENT)
			verbose(env,
				"map '%s' doesn't have 'struct bpf_spin_lock'\n",
				map->name);
		else
			verbose(env,
				"map '%s' is not a struct type or bpf_spin_lock is mangled\n",
				map->name);
		return -EINVAL;
	}
	if (map->spin_lock_off != val + reg->off) {
		verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock'\n",
			val + reg->off);
		return -EINVAL;
	}
	if (is_lock) {
		if (cur->active_spin_lock) {
			verbose(env,
				"Locking two bpf_spin_locks are not allowed\n");
			return -EINVAL;
		}
		cur->active_spin_lock = reg->id;
	} else {
		if (!cur->active_spin_lock) {
			verbose(env, "bpf_spin_unlock without taking a lock\n");
			return -EINVAL;
		}
		if (cur->active_spin_lock != reg->id) {
			verbose(env, "bpf_spin_unlock of different lock\n");
			return -EINVAL;
		}
		cur->active_spin_lock = 0;
	}
	return 0;
}

Project: linux
File: verifier.c

static int __check_stack_boundary(struct bpf_verifier_env *env, u32 regno,
				  int off, int access_size,
				  bool zero_size_allowed)
{
	struct bpf_reg_state *reg = reg_state(env, regno);

	if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 ||
	    access_size < 0 || (access_size == 0 && !zero_size_allowed)) {
		if (tnum_is_const(reg->var_off)) {
			verbose(env, "invalid stack type R%d off=%d access_size=%d\n",
				regno, off, access_size);
		} else {
			char tn_buf[48];

			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
			verbose(env, "invalid stack type R%d var_off=%s access_size=%d\n",
				regno, tn_buf, access_size);
		}
		return -EACCES;
	}
	return 0;
}

Project: linux
File: verifier.c

static void scalar_min_max_or(struct bpf_reg_state *dst_reg,
			      struct bpf_reg_state *src_reg)
{
	s64 smin_val = src_reg->smin_value;
	u64 umin_val = src_reg->umin_value;

	/* We get our maximum from the var_off, and our minimum is the
	 * maximum of the operands' minima
	 */
	dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg->var_off);
	dst_reg->umin_value = max(dst_reg->umin_value, umin_val);
	dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
	if (dst_reg->smin_value < 0 || smin_val < 0) {
		/* Lose signed bounds when ORing negative numbers,
		 * ain't nobody got time for that.
		 */
		dst_reg->smin_value = S64_MIN;
		dst_reg->smax_value = S64_MAX;
	} else {
		/* ORing two positives gives a positive, so safe to
		 * cast result into s64.
		 */
		dst_reg->smin_value = dst_reg->umin_value;
		dst_reg->smax_value = dst_reg->umax_value;
	}
	/* We may learn something more from the var_off */
	__update_reg_bounds(dst_reg);
}

Project: linux
File: verifier.c

static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
				   int access_size, bool zero_size_allowed,
				   struct bpf_call_arg_meta *meta)
{
	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];

	switch (reg->type) {
	case PTR_TO_PACKET:
	case PTR_TO_PACKET_META:
		return check_packet_access(env, regno, reg->off, access_size,
					   zero_size_allowed);
	case PTR_TO_MAP_VALUE:
		if (check_map_access_type(env, regno, reg->off, access_size,
					  meta && meta->raw_mode ? BPF_WRITE :
					  BPF_READ))
			return -EACCES;
		return check_map_access(env, regno, reg->off, access_size,
					zero_size_allowed);
	default: /* scalar_value|ptr_to_stack or invalid ptr */
		return check_stack_boundary(env, regno, access_size,
					    zero_size_allowed, meta);
	}
}

Project: linux
File: verifier.c

static int mark_chain_precision_stack(struct bpf_verifier_env *env, int spi)
{
	return __mark_chain_precision(env, -1, spi);
}

Project: linux
File: verifier.c

static int do_check(struct bpf_verifier_env *env)
{
	struct bpf_verifier_state *state = env->cur_state;
	struct bpf_insn *insns = env->prog->insnsi;
	struct bpf_reg_state *regs;
	int insn_cnt = env->prog->len;
	bool do_print_state = false;
	int prev_insn_idx = -1;

	for (;;) {
		struct bpf_insn *insn;
		u8 class;
		int err;

		env->prev_insn_idx = prev_insn_idx;
		if (env->insn_idx >= insn_cnt) {
			verbose(env, "invalid insn idx %d insn_cnt %d\n",
				env->insn_idx, insn_cnt);
			return -EFAULT;
		}

		insn = &insns[env->insn_idx];
		class = BPF_CLASS(insn->code);

		if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
			verbose(env,
				"BPF program is too large. Processed %d insn\n",
				env->insn_processed);
			return -E2BIG;
		}

		err = is_state_visited(env, env->insn_idx);
		if (err < 0)
			return err;
		if (err == 1) {
			/* found equivalent state, can prune the search */
			if (env->log.level & BPF_LOG_LEVEL) {
				if (do_print_state)
					verbose(env, "\nfrom %d to %d%s: safe\n",
						env->prev_insn_idx, env->insn_idx,
						env->cur_state->speculative ?
						" (speculative execution)" : "");
				else
					verbose(env, "%d: safe\n", env->insn_idx);
			}
			goto process_bpf_exit;
		}

		if (signal_pending(current))
			return -EAGAIN;

		if (need_resched())
			cond_resched();

		if (env->log.level & BPF_LOG_LEVEL2 ||
		    (env->log.level & BPF_LOG_LEVEL && do_print_state)) {
			if (env->log.level & BPF_LOG_LEVEL2)
				verbose(env, "%d:", env->insn_idx);
			else
				verbose(env, "\nfrom %d to %d%s:",
					env->prev_insn_idx, env->insn_idx,
					env->cur_state->speculative ?
					" (speculative execution)" : "");
			print_verifier_state(env, state->frame[state->curframe]);
			do_print_state = false;
		}

		if (env->log.level & BPF_LOG_LEVEL) {
			const struct bpf_insn_cbs cbs = {
				.cb_print	= verbose,
				.private_data	= env,
			};

			verbose_linfo(env, env->insn_idx, "; ");
			verbose(env, "%d: ", env->insn_idx);
			print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
		}

		if (bpf_prog_is_dev_bound(env->prog->aux)) {
			err = bpf_prog_offload_verify_insn(env, env->insn_idx,
							   env->prev_insn_idx);
			if (err)
				return err;
		}

		regs = cur_regs(env);
		env->insn_aux_data[env->insn_idx].seen = env->pass_cnt;
		prev_insn_idx = env->insn_idx;

		if (class == BPF_ALU || class == BPF_ALU64) {
			err = check_alu_op(env, insn);
			if (err)
				return err;

		} else if (class == BPF_LDX) {
			enum bpf_reg_type *prev_src_type, src_reg_type;

			/* check for reserved fields is already done */

			/* check src operand */
			err = check_reg_arg(env, insn->src_reg, SRC_OP);
			if (err)
				return err;

			err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
			if (err)
				return err;

			src_reg_type = regs[insn->src_reg].type;

			/* check that memory (src_reg + off) is readable,
			 * the state of dst_reg will be updated by this func
			 */
			err = check_mem_access(env, env->insn_idx, insn->src_reg,
					       insn->off, BPF_SIZE(insn->code),
					       BPF_READ, insn->dst_reg, false);
			if (err)
				return err;

			prev_src_type = &env->insn_aux_data[env->insn_idx].ptr_type;

			if (*prev_src_type == NOT_INIT) {
				/* saw a valid insn
				 * dst_reg = *(u32 *)(src_reg + off)
				 * save type to validate intersecting paths
				 */
				*prev_src_type = src_reg_type;

			} else if (reg_type_mismatch(src_reg_type, *prev_src_type)) {
				/* ABuser program is trying to use the same insn
				 * dst_reg = *(u32*) (src_reg + off)
				 * with different pointer types:
				 * src_reg == ctx in one branch and
				 * src_reg == stack|map in some other branch.
				 * Reject it.
				 */
				verbose(env, "same insn cannot be used with different pointers\n");
				return -EINVAL;
			}

		} else if (class == BPF_STX) {
			enum bpf_reg_type *prev_dst_type, dst_reg_type;

			if (BPF_MODE(insn->code) == BPF_XADD) {
				err = check_xadd(env, env->insn_idx, insn);
				if (err)
					return err;
				env->insn_idx++;
				continue;
			}

			/* check src1 operand */
			err = check_reg_arg(env, insn->src_reg, SRC_OP);
			if (err)
				return err;
			/* check src2 operand */
			err = check_reg_arg(env, insn->dst_reg, SRC_OP);
			if (err)
				return err;

			dst_reg_type = regs[insn->dst_reg].type;

			/* check that memory (dst_reg + off) is writeable */
			err = check_mem_access(env, env->insn_idx, insn->dst_reg,
					       insn->off, BPF_SIZE(insn->code),
					       BPF_WRITE, insn->src_reg, false);
			if (err)
				return err;

			prev_dst_type = &env->insn_aux_data[env->insn_idx].ptr_type;

			if (*prev_dst_type == NOT_INIT) {
				*prev_dst_type = dst_reg_type;
			} else if (reg_type_mismatch(dst_reg_type, *prev_dst_type)) {
				verbose(env, "same insn cannot be used with different pointers\n");
				return -EINVAL;
			}

		} else if (class == BPF_ST) {
			if (BPF_MODE(insn->code) != BPF_MEM ||
			    insn->src_reg != BPF_REG_0) {
				verbose(env, "BPF_ST uses reserved fields\n");
				return -EINVAL;
			}
			/* check src operand */
			err = check_reg_arg(env, insn->dst_reg, SRC_OP);
			if (err)
				return err;

			if (is_ctx_reg(env, insn->dst_reg)) {
				verbose(env, "BPF_ST stores into R%d %s is not allowed\n",
					insn->dst_reg,
					reg_type_str[reg_state(env, insn->dst_reg)->type]);
				return -EACCES;
			}

			/* check that memory (dst_reg + off) is writeable */
			err = check_mem_access(env, env->insn_idx, insn->dst_reg,
					       insn->off, BPF_SIZE(insn->code),
					       BPF_WRITE, -1, false);
			if (err)
				return err;

		} else if (class == BPF_JMP || class == BPF_JMP32) {
			u8 opcode = BPF_OP(insn->code);

			env->jmps_processed++;
			if (opcode == BPF_CALL) {
				if (BPF_SRC(insn->code) != BPF_K ||
				    insn->off != 0 ||
				    (insn->src_reg != BPF_REG_0 &&
				     insn->src_reg != BPF_PSEUDO_CALL) ||
				    insn->dst_reg != BPF_REG_0 ||
				    class == BPF_JMP32) {
					verbose(env, "BPF_CALL uses reserved fields\n");
					return -EINVAL;
				}

				if (env->cur_state->active_spin_lock &&
				    (insn->src_reg == BPF_PSEUDO_CALL ||
				     insn->imm != BPF_FUNC_spin_unlock)) {
					verbose(env, "function calls are not allowed while holding a lock\n");
					return -EINVAL;
				}
				if (insn->src_reg == BPF_PSEUDO_CALL)
					err = check_func_call(env, insn, &env->insn_idx);
				else
					err = check_helper_call(env, insn->imm, env->insn_idx);
				if (err)
					return err;

			} else if (opcode == BPF_JA) {
				if (BPF_SRC(insn->code) != BPF_K ||
				    insn->imm != 0 ||
				    insn->src_reg != BPF_REG_0 ||
				    insn->dst_reg != BPF_REG_0 ||
				    class == BPF_JMP32) {
					verbose(env, "BPF_JA uses reserved fields\n");
					return -EINVAL;
				}

				env->insn_idx += insn->off + 1;
				continue;

			} else if (opcode == BPF_EXIT) {
				if (BPF_SRC(insn->code) != BPF_K ||
				    insn->imm != 0 ||
				    insn->src_reg != BPF_REG_0 ||
				    insn->dst_reg != BPF_REG_0 ||
				    class == BPF_JMP32) {
					verbose(env, "BPF_EXIT uses reserved fields\n");
					return -EINVAL;
				}

				if (env->cur_state->active_spin_lock) {
					verbose(env, "bpf_spin_unlock is missing\n");
					return -EINVAL;
				}

				if (state->curframe) {
					/* exit from nested function */
					err = prepare_func_exit(env, &env->insn_idx);
					if (err)
						return err;
					do_print_state = true;
					continue;
				}

				err = check_reference_leak(env);
				if (err)
					return err;

				err = check_return_code(env);
				if (err)
					return err;
process_bpf_exit:
				update_branch_counts(env, env->cur_state);
				err = pop_stack(env, &prev_insn_idx,
						&env->insn_idx);
				if (err < 0) {
					if (err != -ENOENT)
						return err;
					break;
				} else {
					do_print_state = true;
					continue;
				}
			} else {
				err = check_cond_jmp_op(env, insn, &env->insn_idx);
				if (err)
					return err;
			}
		} else if (class == BPF_LD) {
			u8 mode = BPF_MODE(insn->code);

			if (mode == BPF_ABS || mode == BPF_IND) {
				err = check_ld_abs(env, insn);
				if (err)
					return err;

			} else if (mode == BPF_IMM) {
				err = check_ld_imm(env, insn);
				if (err)
					return err;

				env->insn_idx++;
				env->insn_aux_data[env->insn_idx].seen = env->pass_cnt;
			} else {
				verbose(env, "invalid BPF_LD mode\n");
				return -EINVAL;
			}
		} else {
			verbose(env, "unknown insn class %d\n", class);
			return -EINVAL;
		}

		env->insn_idx++;
	}

	return 0;
}

Project: linux
File: verifier.c

static int check_subprogs(struct bpf_verifier_env *env)
{
	int i, ret, subprog_start, subprog_end, off, cur_subprog = 0;
	struct bpf_subprog_info *subprog = env->subprog_info;
	struct bpf_insn *insn = env->prog->insnsi;
	int insn_cnt = env->prog->len;

	/* Add entry function. */
	ret = add_subprog(env, 0);
	if (ret < 0)
		return ret;

	/* determine subprog starts. The end is one before the next starts */
	for (i = 0; i < insn_cnt; i++) {
		if (insn[i].code != (BPF_JMP | BPF_CALL))
			continue;
		if (insn[i].src_reg != BPF_PSEUDO_CALL)
			continue;
		if (!env->allow_ptr_leaks) {
			verbose(env, "function calls to other bpf functions are allowed for root only\n");
			return -EPERM;
		}
		ret = add_subprog(env, i + insn[i].imm + 1);
		if (ret < 0)
			return ret;
	}

	/* Add a fake 'exit' subprog which could simplify subprog iteration
	 * logic. 'subprog_cnt' should not be increased.
	 */
	subprog[env->subprog_cnt].start = insn_cnt;

	if (env->log.level & BPF_LOG_LEVEL2)
		for (i = 0; i < env->subprog_cnt; i++)
			verbose(env, "func#%d @%d\n", i, subprog[i].start);

	/* now check that all jumps are within the same subprog */
	subprog_start = subprog[cur_subprog].start;
	subprog_end = subprog[cur_subprog + 1].start;
	for (i = 0; i < insn_cnt; i++) {
		u8 code = insn[i].code;

		if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32)
			goto next;
		if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL)
			goto next;
		off = i + insn[i].off + 1;
		if (off < subprog_start || off >= subprog_end) {
			verbose(env, "jump out of range from insn %d to %d\n", i, off);
			return -EINVAL;
		}
next:
		if (i == subprog_end - 1) {
			/* to avoid fall-through from one subprog into another
			 * the last insn of the subprog should be either exit
			 * or unconditional jump back
			 */
			if (code != (BPF_JMP | BPF_EXIT) &&
			    code != (BPF_JMP | BPF_JA)) {
				verbose(env, "last insn is not an exit or jmp\n");
				return -EINVAL;
			}
			subprog_start = subprog_end;
			cur_subprog++;
			if (cur_subprog < env->subprog_cnt)
				subprog_end = subprog[cur_subprog + 1].start;
		}
	}
	return 0;
}

Project: linux
File: verifier.c

static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur)
{
	if (old->acquired_refs != cur->acquired_refs)
		return false;
	return !memcmp(old->refs, cur->refs,
		       sizeof(*old->refs) * old->acquired_refs);
}

Project: linux
File: verifier.c

static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env)
{
	return &env->insn_aux_data[env->insn_idx];
}

Project: linux
File: verifier.c

static bool reg_type_may_be_null(enum bpf_reg_type type)
{
	return type == PTR_TO_MAP_VALUE_OR_NULL ||
	       type == PTR_TO_SOCKET_OR_NULL ||
	       type == PTR_TO_SOCK_COMMON_OR_NULL ||
	       type == PTR_TO_TCP_SOCK_OR_NULL;
}

Project: linux
File: verifier.c

static bool is_spillable_regtype(enum bpf_reg_type type)
{
	switch (type) {
	case PTR_TO_MAP_VALUE:
	case PTR_TO_MAP_VALUE_OR_NULL:
	case PTR_TO_STACK:
	case PTR_TO_CTX:
	case PTR_TO_PACKET:
	case PTR_TO_PACKET_META:
	case PTR_TO_PACKET_END:
	case PTR_TO_FLOW_KEYS:
	case CONST_PTR_TO_MAP:
	case PTR_TO_SOCKET:
	case PTR_TO_SOCKET_OR_NULL:
	case PTR_TO_SOCK_COMMON:
	case PTR_TO_SOCK_COMMON_OR_NULL:
	case PTR_TO_TCP_SOCK:
	case PTR_TO_TCP_SOCK_OR_NULL:
	case PTR_TO_XDP_SOCK:
	case PTR_TO_BTF_ID:
		return true;
	default:
		return false;
	}
}

Project: linux
File: verifier.c

static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
			       int size, bool zero_size_allowed)
{
	struct bpf_reg_state *regs = cur_regs(env);
	struct bpf_reg_state *reg = &regs[regno];
	int err;

	/* We may have added a variable offset to the packet pointer; but any
	 * reg->range we have comes after that.  We are only checking the fixed
	 * offset.
	 */

	/* We don't allow negative numbers, because we aren't tracking enough
	 * detail to prove they're safe.
	 */
	if (reg->smin_value < 0) {
		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
			regno);
		return -EACCES;
	}
	err = __check_packet_access(env, regno, off, size, zero_size_allowed);
	if (err) {
		verbose(env, "R%d offset is outside of the packet\n", regno);
		return err;
	}

	/* __check_packet_access has made sure "off + size - 1" is within u16.
	 * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
	 * otherwise find_good_pkt_pointers would have refused to set range info
	 * that __check_packet_access would have rejected this pkt access.
	 * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
	 */
	env->prog->aux->max_pkt_offset =
		max_t(u32, env->prog->aux->max_pkt_offset,
		      off + reg->umax_value + size - 1);

	return err;
}

Project: linux
File: verifier.c

static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux)
{
	return aux->map_ptr_state & BPF_MAP_PTR_UNPRIV;
}

Project: linux
File: verifier.c

static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
{
	return type_is_pkt_pointer(reg->type);
}

Project: linux
File: verifier.c

static int release_reference(struct bpf_verifier_env *env,
			     int ref_obj_id)
{
	struct bpf_verifier_state *vstate = env->cur_state;
	int err;
	int i;

	err = release_reference_state(cur_func(env), ref_obj_id);
	if (err)
		return err;

	for (i = 0; i <= vstate->curframe; i++)
		release_reg_references(env, vstate->frame[i], ref_obj_id);

	return 0;
}

Project: linux
File: verifier.c

static void clear_caller_saved_regs(struct bpf_verifier_env *env,
				    struct bpf_reg_state *regs)
{
	int i;

	/* after the call registers r0 - r5 were scratched */
	for (i = 0; i < CALLER_SAVED_REGS; i++) {
		mark_reg_not_init(env, regs, caller_saved[i]);
		check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
	}
}

Project: linux
File: verifier.c

static u32 state_htab_size(struct bpf_verifier_env *env)
{
	return env->prog->len;
}

Project: linux
File: verifier.c

const char *kernel_type_name(u32 id)
{
	return btf_name_by_offset(btf_vmlinux,
				  btf_type_by_id(btf_vmlinux, id)->name_off);
}

Project: linux
File: verifier.c

static void free_states(struct bpf_verifier_env *env)
{
	struct bpf_verifier_state_list *sl, *sln;
	int i;

	sl = env->free_list;
	while (sl) {
		sln = sl->next;
		free_verifier_state(&sl->state, false);
		kfree(sl);
		sl = sln;
	}
	env->free_list = NULL;

	if (!env->explored_states)
		return;

	for (i = 0; i < state_htab_size(env); i++) {
		sl = env->explored_states[i];

		while (sl) {
			sln = sl->next;
			free_verifier_state(&sl->state, false);
			kfree(sl);
			sl = sln;
		}
		env->explored_states[i] = NULL;
	}
}

Project: linux
File: verifier.c

static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env,
					      u32 off, u32 cnt)
{
	int i, j;

	/* find first prog starting at or after off (first to remove) */
	for (i = 0; i < env->subprog_cnt; i++)
		if (env->subprog_info[i].start >= off)
			break;
	/* find first prog starting at or after off + cnt (first to stay) */
	for (j = i; j < env->subprog_cnt; j++)
		if (env->subprog_info[j].start >= off + cnt)
			break;
	/* if j doesn't start exactly at off + cnt, we are just removing
	 * the front of previous prog
	 */
	if (env->subprog_info[j].start != off + cnt)
		j--;

	if (j > i) {
		struct bpf_prog_aux *aux = env->prog->aux;
		int move;

		/* move fake 'exit' subprog as well */
		move = env->subprog_cnt + 1 - j;

		memmove(env->subprog_info + i,
			env->subprog_info + j,
			sizeof(*env->subprog_info) * move);
		env->subprog_cnt -= j - i;

		/* remove func_info */
		if (aux->func_info) {
			move = aux->func_info_cnt - j;

			memmove(aux->func_info + i,
				aux->func_info + j,
				sizeof(*aux->func_info) * move);
			aux->func_info_cnt -= j - i;
			/* func_info->insn_off is set after all code rewrites,
			 * in adjust_btf_func() - no need to adjust
			 */
		}
	} else {
		/* convert i from "first prog to remove" to "first to adjust" */
		if (env->subprog_info[i].start == off)
			i++;
	}

	/* update fake 'exit' subprog as well */
	for (; i <= env->subprog_cnt; i++)
		env->subprog_info[i].start -= cnt;

	return 0;
}

Project: linux
File: verifier.c

static bool states_maybe_looping(struct bpf_verifier_state *old,
				 struct bpf_verifier_state *cur)
{
	struct bpf_func_state *fold, *fcur;
	int i, fr = cur->curframe;

	if (old->curframe != fr)
		return false;

	fold = old->frame[fr];
	fcur = cur->frame[fr];
	for (i = 0; i < MAX_BPF_REG; i++)
		if (memcmp(&fold->regs[i], &fcur->regs[i],
			   offsetof(struct bpf_reg_state, parent)))
			return false;
	return true;
}

Project: linux
File: verifier.c

static int check_attach_btf_id(struct bpf_verifier_env *env)
{
	struct bpf_prog *prog = env->prog;
	bool prog_extension = prog->type == BPF_PROG_TYPE_EXT;
	struct bpf_prog *tgt_prog = prog->aux->linked_prog;
	u32 btf_id = prog->aux->attach_btf_id;
	const char prefix[] = "btf_trace_";
	int ret = 0, subprog = -1, i;
	struct bpf_trampoline *tr;
	const struct btf_type *t;
	bool conservative = true;
	const char *tname;
	struct btf *btf;
	long addr;
	u64 key;

	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS)
		return check_struct_ops_btf_id(env);

	if (prog->type != BPF_PROG_TYPE_TRACING && !prog_extension)
		return 0;

	if (!btf_id) {
		verbose(env, "Tracing programs must provide btf_id\n");
		return -EINVAL;
	}
	btf = bpf_prog_get_target_btf(prog);
	if (!btf) {
		verbose(env,
			"FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
		return -EINVAL;
	}
	t = btf_type_by_id(btf, btf_id);
	if (!t) {
		verbose(env, "attach_btf_id %u is invalid\n", btf_id);
		return -EINVAL;
	}
	tname = btf_name_by_offset(btf, t->name_off);
	if (!tname) {
		verbose(env, "attach_btf_id %u doesn't have a name\n", btf_id);
		return -EINVAL;
	}
	if (tgt_prog) {
		struct bpf_prog_aux *aux = tgt_prog->aux;

		for (i = 0; i < aux->func_info_cnt; i++)
			if (aux->func_info[i].type_id == btf_id) {
				subprog = i;
				break;
			}
		if (subprog == -1) {
			verbose(env, "Subprog %s doesn't exist\n", tname);
			return -EINVAL;
		}
		conservative = aux->func_info_aux[subprog].unreliable;
		if (prog_extension) {
			if (conservative) {
				verbose(env,
					"Cannot replace static functions\n");
				return -EINVAL;
			}
			if (!prog->jit_requested) {
				verbose(env,
					"Extension programs should be JITed\n");
				return -EINVAL;
			}
			env->ops = bpf_verifier_ops[tgt_prog->type];
		}
		if (!tgt_prog->jited) {
			verbose(env, "Can attach to only JITed progs\n");
			return -EINVAL;
		}
		if (tgt_prog->type == prog->type) {
			/* Cannot fentry/fexit another fentry/fexit program.
			 * Cannot attach program extension to another extension.
			 * It's ok to attach fentry/fexit to extension program.
			 */
			verbose(env, "Cannot recursively attach\n");
			return -EINVAL;
		}
		if (tgt_prog->type == BPF_PROG_TYPE_TRACING &&
		    prog_extension &&
		    (tgt_prog->expected_attach_type == BPF_TRACE_FENTRY ||
		     tgt_prog->expected_attach_type == BPF_TRACE_FEXIT)) {
			/* Program extensions can extend all program types
			 * except fentry/fexit. The reason is the following.
			 * The fentry/fexit programs are used for performance
			 * analysis, stats and can be attached to any program
			 * type except themselves. When extension program is
			 * replacing XDP function it is necessary to allow
			 * performance analysis of all functions. Both original
			 * XDP program and its program extension. Hence
			 * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
			 * allowed. If extending of fentry/fexit was allowed it
			 * would be possible to create long call chain
			 * fentry->extension->fentry->extension beyond
			 * reasonable stack size. Hence extending fentry is not
			 * allowed.
			 */
			verbose(env, "Cannot extend fentry/fexit\n");
			return -EINVAL;
		}
		key = ((u64)aux->id) << 32 | btf_id;
	} else {
		if (prog_extension) {
			verbose(env, "Cannot replace kernel functions\n");
			return -EINVAL;
		}
		key = btf_id;
	}

	switch (prog->expected_attach_type) {
	case BPF_TRACE_RAW_TP:
		if (tgt_prog) {
			verbose(env,
				"Only FENTRY/FEXIT progs are attachable to another BPF prog\n");
			return -EINVAL;
		}
		if (!btf_type_is_typedef(t)) {
			verbose(env, "attach_btf_id %u is not a typedef\n",
				btf_id);
			return -EINVAL;
		}
		if (strncmp(prefix, tname, sizeof(prefix) - 1)) {
			verbose(env, "attach_btf_id %u points to wrong type name %s\n",
				btf_id, tname);
			return -EINVAL;
		}
		tname += sizeof(prefix) - 1;
		t = btf_type_by_id(btf, t->type);
		if (!btf_type_is_ptr(t))
			/* should never happen in valid vmlinux build */
			return -EINVAL;
		t = btf_type_by_id(btf, t->type);
		if (!btf_type_is_func_proto(t))
			/* should never happen in valid vmlinux build */
			return -EINVAL;

		/* remember two read only pointers that are valid for
		 * the life time of the kernel
		 */
		prog->aux->attach_func_name = tname;
		prog->aux->attach_func_proto = t;
		prog->aux->attach_btf_trace = true;
		return 0;
	default:
		if (!prog_extension)
			return -EINVAL;
		/* fallthrough */
	case BPF_MODIFY_RETURN:
	case BPF_TRACE_FENTRY:
	case BPF_TRACE_FEXIT:
		if (!btf_type_is_func(t)) {
			verbose(env, "attach_btf_id %u is not a function\n",
				btf_id);
			return -EINVAL;
		}
		if (prog_extension &&
		    btf_check_type_match(env, prog, btf, t))
			return -EINVAL;
		t = btf_type_by_id(btf, t->type);
		if (!btf_type_is_func_proto(t))
			return -EINVAL;
		tr = bpf_trampoline_lookup(key);
		if (!tr)
			return -ENOMEM;
		prog->aux->attach_func_name = tname;
		/* t is either vmlinux type or another program's type */
		prog->aux->attach_func_proto = t;
		mutex_lock(&tr->mutex);
		if (tr->func.addr) {
			prog->aux->trampoline = tr;
			goto out;
		}
		if (tgt_prog && conservative) {
			prog->aux->attach_func_proto = NULL;
			t = NULL;
		}
		ret = btf_distill_func_proto(&env->log, btf, t,
					     tname, &tr->func.model);
		if (ret < 0)
			goto out;
		if (tgt_prog) {
			if (subprog == 0)
				addr = (long) tgt_prog->bpf_func;
			else
				addr = (long) tgt_prog->aux->func[subprog]->bpf_func;
		} else {
			addr = kallsyms_lookup_name(tname);
			if (!addr) {
				verbose(env,
					"The address of function %s cannot be found\n",
					tname);
				ret = -ENOENT;
				goto out;
			}
		}
		tr->func.addr = (void *)addr;
		prog->aux->trampoline = tr;

		if (prog->expected_attach_type == BPF_MODIFY_RETURN)
			ret = check_attach_modify_return(env);
out:
		mutex_unlock(&tr->mutex);
		if (ret)
			bpf_trampoline_put(tr);
		return ret;
	}
}

Project: linux
File: verifier.c

static bool func_states_equal(struct bpf_func_state *old,
			      struct bpf_func_state *cur)
{
	struct idpair *idmap;
	bool ret = false;
	int i;

	idmap = kcalloc(ID_MAP_SIZE, sizeof(struct idpair), GFP_KERNEL);
	/* If we failed to allocate the idmap, just say it's not safe */
	if (!idmap)
		return false;

	for (i = 0; i < MAX_BPF_REG; i++) {
		if (!regsafe(&old->regs[i], &cur->regs[i], idmap))
			goto out_free;
	}

	if (!stacksafe(old, cur, idmap))
		goto out_free;

	if (!refsafe(old, cur))
		goto out_free;
	ret = true;
out_free:
	kfree(idmap);
	return ret;
}

Project: linux
File: verifier.c

static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
{
	struct bpf_verifier_state *state = env->cur_state;
	struct bpf_func_state *caller, *callee;
	struct bpf_reg_state *r0;
	int err;

	callee = state->frame[state->curframe];
	r0 = &callee->regs[BPF_REG_0];
	if (r0->type == PTR_TO_STACK) {
		/* technically it's ok to return caller's stack pointer
		 * (or caller's caller's pointer) back to the caller,
		 * since these pointers are valid. Only current stack
		 * pointer will be invalid as soon as function exits,
		 * but let's be conservative
		 */
		verbose(env, "cannot return stack pointer to the caller\n");
		return -EINVAL;
	}

	state->curframe--;
	caller = state->frame[state->curframe];
	/* return to the caller whatever r0 had in the callee */
	caller->regs[BPF_REG_0] = *r0;

	/* Transfer references to the caller */
	err = transfer_reference_state(caller, callee);
	if (err)
		return err;

	*insn_idx = callee->callsite + 1;
	if (env->log.level & BPF_LOG_LEVEL) {
		verbose(env, "returning from callee:\n");
		print_verifier_state(env, callee);
		verbose(env, "to caller at %d:\n", *insn_idx);
		print_verifier_state(env, caller);
	}
	/* clear everything in the callee */
	free_func_state(callee);
	state->frame[state->curframe + 1] = NULL;
	return 0;
}

Project: linux
File: verifier.c

static void clear_jmp_history(struct bpf_verifier_state *state)
{
	kfree(state->jmp_history);
	state->jmp_history = NULL;
	state->jmp_history_cnt = 0;
}

Project: linux
File: verifier.c

static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
				   struct bpf_reg_state *dst_reg,
				   enum bpf_reg_type type,
				   bool range_right_open)
{
	u16 new_range;
	int i;

	if (dst_reg->off < 0 ||
	    (dst_reg->off == 0 && range_right_open))
		/* This doesn't give us any range */
		return;

	if (dst_reg->umax_value > MAX_PACKET_OFF ||
	    dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF)
		/* Risk of overflow.  For instance, ptr + (1<<63) may be less
		 * than pkt_end, but that's because it's also less than pkt.
		 */
		return;

	new_range = dst_reg->off;
	if (range_right_open)
		new_range--;

	/* Examples for register markings:
	 *
	 * pkt_data in dst register:
	 *
	 *   r2 = r3;
	 *   r2 += 8;
	 *   if (r2 > pkt_end) goto <handle exception>
	 *   <access okay>
	 *
	 *   r2 = r3;
	 *   r2 += 8;
	 *   if (r2 < pkt_end) goto <access okay>
	 *   <handle exception>
	 *
	 *   Where:
	 *     r2 == dst_reg, pkt_end == src_reg
	 *     r2=pkt(id=n,off=8,r=0)
	 *     r3=pkt(id=n,off=0,r=0)
	 *
	 * pkt_data in src register:
	 *
	 *   r2 = r3;
	 *   r2 += 8;
	 *   if (pkt_end >= r2) goto <access okay>
	 *   <handle exception>
	 *
	 *   r2 = r3;
	 *   r2 += 8;
	 *   if (pkt_end <= r2) goto <handle exception>
	 *   <access okay>
	 *
	 *   Where:
	 *     pkt_end == dst_reg, r2 == src_reg
	 *     r2=pkt(id=n,off=8,r=0)
	 *     r3=pkt(id=n,off=0,r=0)
	 *
	 * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
	 * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8)
	 * and [r3, r3 + 8-1) respectively is safe to access depending on
	 * the check.
	 */

	/* If our ids match, then we must have the same max_value.  And we
	 * don't care about the other reg's fixed offset, since if it's too big
	 * the range won't allow anything.
	 * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
	 */
	for (i = 0; i <= vstate->curframe; i++)
		__find_good_pkt_pointers(vstate->frame[i], dst_reg, type,
					 new_range);
}

Project: linux
File: verifier.c

static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
{
	struct bpf_reg_state *regs = cur_regs(env);
	u8 opcode = BPF_OP(insn->code);
	int err;

	if (opcode == BPF_END || opcode == BPF_NEG) {
		if (opcode == BPF_NEG) {
			if (BPF_SRC(insn->code) != 0 ||
			    insn->src_reg != BPF_REG_0 ||
			    insn->off != 0 || insn->imm != 0) {
				verbose(env, "BPF_NEG uses reserved fields\n");
				return -EINVAL;
			}
		} else {
			if (insn->src_reg != BPF_REG_0 || insn->off != 0 ||
			    (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) ||
			    BPF_CLASS(insn->code) == BPF_ALU64) {
				verbose(env, "BPF_END uses reserved fields\n");
				return -EINVAL;
			}
		}

		/* check src operand */
		err = check_reg_arg(env, insn->dst_reg, SRC_OP);
		if (err)
			return err;

		if (is_pointer_value(env, insn->dst_reg)) {
			verbose(env, "R%d pointer arithmetic prohibited\n",
				insn->dst_reg);
			return -EACCES;
		}

		/* check dest operand */
		err = check_reg_arg(env, insn->dst_reg, DST_OP);
		if (err)
			return err;

	} else if (opcode == BPF_MOV) {

		if (BPF_SRC(insn->code) == BPF_X) {
			if (insn->imm != 0 || insn->off != 0) {
				verbose(env, "BPF_MOV uses reserved fields\n");
				return -EINVAL;
			}

			/* check src operand */
			err = check_reg_arg(env, insn->src_reg, SRC_OP);
			if (err)
				return err;
		} else {
			if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
				verbose(env, "BPF_MOV uses reserved fields\n");
				return -EINVAL;
			}
		}

		/* check dest operand, mark as required later */
		err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
		if (err)
			return err;

		if (BPF_SRC(insn->code) == BPF_X) {
			struct bpf_reg_state *src_reg = regs + insn->src_reg;
			struct bpf_reg_state *dst_reg = regs + insn->dst_reg;

			if (BPF_CLASS(insn->code) == BPF_ALU64) {
				/* case: R1 = R2
				 * copy register state to dest reg
				 */
				*dst_reg = *src_reg;
				dst_reg->live |= REG_LIVE_WRITTEN;
				dst_reg->subreg_def = DEF_NOT_SUBREG;
			} else {
				/* R1 = (u32) R2 */
				if (is_pointer_value(env, insn->src_reg)) {
					verbose(env,
						"R%d partial copy of pointer\n",
						insn->src_reg);
					return -EACCES;
				} else if (src_reg->type == SCALAR_VALUE) {
					*dst_reg = *src_reg;
					dst_reg->live |= REG_LIVE_WRITTEN;
					dst_reg->subreg_def = env->insn_idx + 1;
				} else {
					mark_reg_unknown(env, regs,
							 insn->dst_reg);
				}
				coerce_reg_to_size(dst_reg, 4);
			}
		} else {
			/* case: R = imm
			 * remember the value we stored into this reg
			 */
			/* clear any state __mark_reg_known doesn't set */
			mark_reg_unknown(env, regs, insn->dst_reg);
			regs[insn->dst_reg].type = SCALAR_VALUE;
			if (BPF_CLASS(insn->code) == BPF_ALU64) {
				__mark_reg_known(regs + insn->dst_reg,
						 insn->imm);
			} else {
				__mark_reg_known(regs + insn->dst_reg,
						 (u32)insn->imm);
			}
		}

	} else if (opcode > BPF_END) {
		verbose(env, "invalid BPF_ALU opcode %x\n", opcode);
		return -EINVAL;

	} else {	/* all other ALU ops: and, sub, xor, add, ... */

		if (BPF_SRC(insn->code) == BPF_X) {
			if (insn->imm != 0 || insn->off != 0) {
				verbose(env, "BPF_ALU uses reserved fields\n");
				return -EINVAL;
			}
			/* check src1 operand */
			err = check_reg_arg(env, insn->src_reg, SRC_OP);
			if (err)
				return err;
		} else {
			if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
				verbose(env, "BPF_ALU uses reserved fields\n");
				return -EINVAL;
			}
		}

		/* check src2 operand */
		err = check_reg_arg(env, insn->dst_reg, SRC_OP);
		if (err)
			return err;

		if ((opcode == BPF_MOD || opcode == BPF_DIV) &&
		    BPF_SRC(insn->code) == BPF_K && insn->imm == 0) {
			verbose(env, "div by zero\n");
			return -EINVAL;
		}

		if ((opcode == BPF_LSH || opcode == BPF_RSH ||
		     opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) {
			int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32;

			if (insn->imm < 0 || insn->imm >= size) {
				verbose(env, "invalid shift %d\n", insn->imm);
				return -EINVAL;
			}
		}

		/* check dest operand */
		err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
		if (err)
			return err;

		return adjust_reg_min_max_vals(env, insn);
	}

	return 0;
}

Project: linux
File: verifier.c

static bool range_within(struct bpf_reg_state *old,
			 struct bpf_reg_state *cur)
{
	return old->umin_value <= cur->umin_value &&
	       old->umax_value >= cur->umax_value &&
	       old->smin_value <= cur->smin_value &&
	       old->smax_value >= cur->smax_value;
}

Project: linux
File: verifier.c

static int sanitize_ptr_alu(struct bpf_verifier_env *env,
			    struct bpf_insn *insn,
			    const struct bpf_reg_state *ptr_reg,
			    struct bpf_reg_state *dst_reg,
			    bool off_is_neg)
{
	struct bpf_verifier_state *vstate = env->cur_state;
	struct bpf_insn_aux_data *aux = cur_aux(env);
	bool ptr_is_dst_reg = ptr_reg == dst_reg;
	u8 opcode = BPF_OP(insn->code);
	u32 alu_state, alu_limit;
	struct bpf_reg_state tmp;
	bool ret;

	if (can_skip_alu_sanitation(env, insn))
		return 0;

	/* We already marked aux for masking from non-speculative
	 * paths, thus we got here in the first place. We only care
	 * to explore bad access from here.
	 */
	if (vstate->speculative)
		goto do_sim;

	alu_state  = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
	alu_state |= ptr_is_dst_reg ?
		     BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST;

	if (retrieve_ptr_limit(ptr_reg, &alu_limit, opcode, off_is_neg))
		return 0;
	if (update_alu_sanitation_state(aux, alu_state, alu_limit))
		return -EACCES;
do_sim:
	/* Simulate and find potential out-of-bounds access under
	 * speculative execution from truncation as a result of
	 * masking when off was not within expected range. If off
	 * sits in dst, then we temporarily need to move ptr there
	 * to simulate dst (== 0) +/-= ptr. Needed, for example,
	 * for cases where we use K-based arithmetic in one direction
	 * and truncated reg-based in the other in order to explore
	 * bad access.
	 */
	if (!ptr_is_dst_reg) {
		tmp = *dst_reg;
		*dst_reg = *ptr_reg;
	}
	ret = push_stack(env, env->insn_idx + 1, env->insn_idx, true);
	if (!ptr_is_dst_reg && ret)
		*dst_reg = tmp;
	return !ret ? -EFAULT : 0;
}

Project: linux
File: verifier.c

static int int_ptr_type_to_size(enum bpf_arg_type type)
{
	if (type == ARG_PTR_TO_INT)
		return sizeof(u32);
	else if (type == ARG_PTR_TO_LONG)
		return sizeof(u64);

	return -EINVAL;
}

Project: linux
File: verifier.c

static bool try_match_pkt_pointers(const struct bpf_insn *insn,
				   struct bpf_reg_state *dst_reg,
				   struct bpf_reg_state *src_reg,
				   struct bpf_verifier_state *this_branch,
				   struct bpf_verifier_state *other_branch)
{
	if (BPF_SRC(insn->code) != BPF_X)
		return false;

	/* Pointers are always 64-bit. */
	if (BPF_CLASS(insn->code) == BPF_JMP32)
		return false;

	switch (BPF_OP(insn->code)) {
	case BPF_JGT:
		if ((dst_reg->type == PTR_TO_PACKET &&
		     src_reg->type == PTR_TO_PACKET_END) ||
		    (dst_reg->type == PTR_TO_PACKET_META &&
		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
			/* pkt_data' > pkt_end, pkt_meta' > pkt_data */
			find_good_pkt_pointers(this_branch, dst_reg,
					       dst_reg->type, false);
		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
			    src_reg->type == PTR_TO_PACKET) ||
			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
			    src_reg->type == PTR_TO_PACKET_META)) {
			/* pkt_end > pkt_data', pkt_data > pkt_meta' */
			find_good_pkt_pointers(other_branch, src_reg,
					       src_reg->type, true);
		} else {
			return false;
		}
		break;
	case BPF_JLT:
		if ((dst_reg->type == PTR_TO_PACKET &&
		     src_reg->type == PTR_TO_PACKET_END) ||
		    (dst_reg->type == PTR_TO_PACKET_META &&
		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
			/* pkt_data' < pkt_end, pkt_meta' < pkt_data */
			find_good_pkt_pointers(other_branch, dst_reg,
					       dst_reg->type, true);
		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
			    src_reg->type == PTR_TO_PACKET) ||
			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
			    src_reg->type == PTR_TO_PACKET_META)) {
			/* pkt_end < pkt_data', pkt_data > pkt_meta' */
			find_good_pkt_pointers(this_branch, src_reg,
					       src_reg->type, false);
		} else {
			return false;
		}
		break;
	case BPF_JGE:
		if ((dst_reg->type == PTR_TO_PACKET &&
		     src_reg->type == PTR_TO_PACKET_END) ||
		    (dst_reg->type == PTR_TO_PACKET_META &&
		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
			/* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
			find_good_pkt_pointers(this_branch, dst_reg,
					       dst_reg->type, true);
		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
			    src_reg->type == PTR_TO_PACKET) ||
			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
			    src_reg->type == PTR_TO_PACKET_META)) {
			/* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
			find_good_pkt_pointers(other_branch, src_reg,
					       src_reg->type, false);
		} else {
			return false;
		}
		break;
	case BPF_JLE:
		if ((dst_reg->type == PTR_TO_PACKET &&
		     src_reg->type == PTR_TO_PACKET_END) ||
		    (dst_reg->type == PTR_TO_PACKET_META &&
		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
			/* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
			find_good_pkt_pointers(other_branch, dst_reg,
					       dst_reg->type, false);
		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
			    src_reg->type == PTR_TO_PACKET) ||
			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
			    src_reg->type == PTR_TO_PACKET_META)) {
			/* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
			find_good_pkt_pointers(this_branch, src_reg,
					       src_reg->type, true);
		} else {
			return false;
		}
		break;
	default:
		return false;
	}

	return true;
}

Project: linux
File: verifier.c

static struct bpf_verifier_state_list **explored_state(
					struct bpf_verifier_env *env,
					int idx)
{
	struct bpf_verifier_state *cur = env->cur_state;
	struct bpf_func_state *state = cur->frame[cur->curframe];

	return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)];
}

Project: linux
File: verifier.c

static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
				struct bpf_reg_state *false_reg, u64 val,
				u8 opcode, bool is_jmp32)
{
	s64 sval;

	if (__is_pointer_value(false, false_reg))
		return;

	val = is_jmp32 ? (u32)val : val;
	sval = is_jmp32 ? (s64)(s32)val : (s64)val;

	switch (opcode) {
	case BPF_JEQ:
	case BPF_JNE:
	{
		struct bpf_reg_state *reg =
			opcode == BPF_JEQ ? true_reg : false_reg;

		if (is_jmp32) {
			u64 old_v = reg->var_off.value;
			u64 hi_mask = ~0xffffffffULL;

			reg->var_off.value = (old_v & hi_mask) | val;
			reg->var_off.mask &= hi_mask;
		} else {
			__mark_reg_known(reg, val);
		}
		break;
	}
	case BPF_JSET:
		false_reg->var_off = tnum_and(false_reg->var_off,
					      tnum_const(~val));
		if (is_power_of_2(val))
			true_reg->var_off = tnum_or(true_reg->var_off,
						    tnum_const(val));
		break;
	case BPF_JGE:
	case BPF_JGT:
	{
		u64 false_umin = opcode == BPF_JGT ? val    : val + 1;
		u64 true_umax = opcode == BPF_JGT ? val - 1 : val;

		if (is_jmp32) {
			false_umin += gen_hi_min(false_reg->var_off);
			true_umax += gen_hi_max(true_reg->var_off);
		}
		false_reg->umin_value = max(false_reg->umin_value, false_umin);
		true_reg->umax_value = min(true_reg->umax_value, true_umax);
		break;
	}
	case BPF_JSGE:
	case BPF_JSGT:
	{
		s64 false_smin = opcode == BPF_JSGT ? sval    : sval + 1;
		s64 true_smax = opcode == BPF_JSGT ? sval - 1 : sval;

		if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg))
			break;
		false_reg->smin_value = max(false_reg->smin_value, false_smin);
		true_reg->smax_value = min(true_reg->smax_value, true_smax);
		break;
	}
	case BPF_JLE:
	case BPF_JLT:
	{
		u64 false_umax = opcode == BPF_JLT ? val    : val - 1;
		u64 true_umin = opcode == BPF_JLT ? val + 1 : val;

		if (is_jmp32) {
			false_umax += gen_hi_max(false_reg->var_off);
			true_umin += gen_hi_min(true_reg->var_off);
		}
		false_reg->umax_value = min(false_reg->umax_value, false_umax);
		true_reg->umin_value = max(true_reg->umin_value, true_umin);
		break;
	}
	case BPF_JSLE:
	case BPF_JSLT:
	{
		s64 false_smax = opcode == BPF_JSLT ? sval    : sval - 1;
		s64 true_smin = opcode == BPF_JSLT ? sval + 1 : sval;

		if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg))
			break;
		false_reg->smax_value = min(false_reg->smax_value, false_smax);
		true_reg->smin_value = max(true_reg->smin_value, true_smin);
		break;
	}
	default:
		break;
	}

	__reg_deduce_bounds(false_reg);
	__reg_deduce_bounds(true_reg);
	/* We might have learned some bits from the bounds. */
	__reg_bound_offset(false_reg);
	__reg_bound_offset(true_reg);
	if (is_jmp32) {
		__reg_bound_offset32(false_reg);
		__reg_bound_offset32(true_reg);
	}
	/* Intersecting with the old var_off might have improved our bounds
	 * slightly.  e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
	 * then new var_off is (0; 0x7f...fc) which improves our umax.
	 */
	__update_reg_bounds(false_reg);
	__update_reg_bounds(true_reg);
}

Project: linux
File: verifier.c

static int propagate_liveness(struct bpf_verifier_env *env,
			      const struct bpf_verifier_state *vstate,
			      struct bpf_verifier_state *vparent)
{
	struct bpf_reg_state *state_reg, *parent_reg;
	struct bpf_func_state *state, *parent;
	int i, frame, err = 0;

	if (vparent->curframe != vstate->curframe) {
		WARN(1, "propagate_live: parent frame %d current frame %d\n",
		     vparent->curframe, vstate->curframe);
		return -EFAULT;
	}
	/* Propagate read liveness of registers... */
	BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
	for (frame = 0; frame <= vstate->curframe; frame++) {
		parent = vparent->frame[frame];
		state = vstate->frame[frame];
		parent_reg = parent->regs;
		state_reg = state->regs;
		/* We don't need to worry about FP liveness, it's read-only */
		for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) {
			err = propagate_liveness_reg(env, &state_reg[i],
						     &parent_reg[i]);
			if (err < 0)
				return err;
			if (err == REG_LIVE_READ64)
				mark_insn_zext(env, &parent_reg[i]);
		}

		/* Propagate stack slots. */
		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&
			    i < parent->allocated_stack / BPF_REG_SIZE; i++) {
			parent_reg = &parent->stack[i].spilled_ptr;
			state_reg = &state->stack[i].spilled_ptr;
			err = propagate_liveness_reg(env, state_reg,
						     parent_reg);
			if (err < 0)
				return err;
		}
	}
	return 0;
}

Project: linux
File: verifier.c

static void clean_verifier_state(struct bpf_verifier_env *env,
				 struct bpf_verifier_state *st)
{
	int i;

	if (st->frame[0]->regs[0].live & REG_LIVE_DONE)
		/* all regs in this state in all frames were already marked */
		return;

	for (i = 0; i <= st->curframe; i++)
		clean_func_state(env, st->frame[i]);
}

Project: linux
File: verifier.c

static void free_func_state(struct bpf_func_state *state)
{
	if (!state)
		return;
	kfree(state->refs);
	kfree(state->stack);
	kfree(state);
}

Project: linux
File: verifier.c

static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
				       const struct bpf_call_arg_meta *meta,
				       enum bpf_access_type t)
{
	switch (env->prog->type) {
	/* Program types only with direct read access go here! */
	case BPF_PROG_TYPE_LWT_IN:
	case BPF_PROG_TYPE_LWT_OUT:
	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
	case BPF_PROG_TYPE_SK_REUSEPORT:
	case BPF_PROG_TYPE_FLOW_DISSECTOR:
	case BPF_PROG_TYPE_CGROUP_SKB:
		if (t == BPF_WRITE)
			return false;
		/* fallthrough */

	/* Program types with direct read + write access go here! */
	case BPF_PROG_TYPE_SCHED_CLS:
	case BPF_PROG_TYPE_SCHED_ACT:
	case BPF_PROG_TYPE_XDP:
	case BPF_PROG_TYPE_LWT_XMIT:
	case BPF_PROG_TYPE_SK_SKB:
	case BPF_PROG_TYPE_SK_MSG:
		if (meta)
			return meta->pkt_access;

		env->seen_direct_write = true;
		return true;

	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
		if (t == BPF_WRITE)
			env->seen_direct_write = true;

		return true;

	default:
		return false;
	}
}

Project: linux
File: verifier.c

static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size,
			    enum bpf_access_type t, enum bpf_reg_type *reg_type,
			    u32 *btf_id)
{
	struct bpf_insn_access_aux info = {
		.reg_type = *reg_type,
		.log = &env->log,
	};

	if (env->ops->is_valid_access &&
	    env->ops->is_valid_access(off, size, t, env->prog, &info)) {
		/* A non zero info.ctx_field_size indicates that this field is a
		 * candidate for later verifier transformation to load the whole
		 * field and then apply a mask when accessed with a narrower
		 * access than actual ctx access size. A zero info.ctx_field_size
		 * will only allow for whole field access and rejects any other
		 * type of narrower access.
		 */
		*reg_type = info.reg_type;

		if (*reg_type == PTR_TO_BTF_ID)
			*btf_id = info.btf_id;
		else
			env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size;
		/* remember the offset of last byte accessed in ctx */
		if (env->prog->aux->max_ctx_offset < off + size)
			env->prog->aux->max_ctx_offset = off + size;
		return 0;
	}

	verbose(env, "invalid bpf_context access off=%d size=%d\n", off, size);
	return -EACCES;
}

Project: linux
File: verifier.c

static int push_insn(int t, int w, int e, struct bpf_verifier_env *env,
		     bool loop_ok)
{
	int *insn_stack = env->cfg.insn_stack;
	int *insn_state = env->cfg.insn_state;

	if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH))
		return 0;

	if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH))
		return 0;

	if (w < 0 || w >= env->prog->len) {
		verbose_linfo(env, t, "%d: ", t);
		verbose(env, "jump out of range from insn %d to %d\n", t, w);
		return -EINVAL;
	}

	if (e == BRANCH)
		/* mark branch target for state pruning */
		init_explored_state(env, w);

	if (insn_state[w] == 0) {
		/* tree-edge */
		insn_state[t] = DISCOVERED | e;
		insn_state[w] = DISCOVERED;
		if (env->cfg.cur_stack >= env->prog->len)
			return -E2BIG;
		insn_stack[env->cfg.cur_stack++] = w;
		return 1;
	} else if ((insn_state[w] & 0xF0) == DISCOVERED) {
		if (loop_ok && env->allow_ptr_leaks)
			return 0;
		verbose_linfo(env, t, "%d: ", t);
		verbose_linfo(env, w, "%d: ", w);
		verbose(env, "back-edge from insn %d to %d\n", t, w);
		return -EINVAL;
	} else if (insn_state[w] == EXPLORED) {
		/* forward- or cross-edge */
		insn_state[t] = DISCOVERED | e;
	} else {
		verbose(env, "insn state internal bug\n");
		return -EFAULT;
	}
	return 0;
}

Project: linux
File: verifier.c

static void mark_reg_unknown(struct bpf_verifier_env *env,
			     struct bpf_reg_state *regs, u32 regno)
{
	if (WARN_ON(regno >= MAX_BPF_REG)) {
		verbose(env, "mark_reg_unknown(regs, %u)\n", regno);
		/* Something bad happened, let's kill all regs except FP */
		for (regno = 0; regno < BPF_REG_FP; regno++)
			__mark_reg_not_init(env, regs + regno);
		return;
	}
	__mark_reg_unknown(env, regs + regno);
}

Project: linux
File: verifier.c

static int transfer_reference_state(struct bpf_func_state *dst,
				    struct bpf_func_state *src)
{
	int err = realloc_reference_state(dst, src->acquired_refs, false);
	if (err)
		return err;
	err = copy_reference_state(dst, src);
	if (err)
		return err;
	return 0;
}

Project: linux
File: verifier.c

static void __find_good_pkt_pointers(struct bpf_func_state *state,
				     struct bpf_reg_state *dst_reg,
				     enum bpf_reg_type type, u16 new_range)
{
	struct bpf_reg_state *reg;
	int i;

	for (i = 0; i < MAX_BPF_REG; i++) {
		reg = &state->regs[i];
		if (reg->type == type && reg->id == dst_reg->id)
			/* keep the maximum range already checked */
			reg->range = max(reg->range, new_range);
	}

	bpf_for_each_spilled_reg(i, state, reg) {
		if (!reg)
			continue;
		if (reg->type == type && reg->id == dst_reg->id)
			reg->range = max(reg->range, new_range);
	}
}

Project: linux
File: verifier.c

static int release_reference_state(struct bpf_func_state *state, int ptr_id)
{
	int i, last_idx;

	last_idx = state->acquired_refs - 1;
	for (i = 0; i < state->acquired_refs; i++) {
		if (state->refs[i].id == ptr_id) {
			if (last_idx && i != last_idx)
				memcpy(&state->refs[i], &state->refs[last_idx],
				       sizeof(*state->refs));
			memset(&state->refs[last_idx], 0, sizeof(*state->refs));
			state->acquired_refs--;
			return 0;
		}
	}
	return -EINVAL;
}

Project: linux
File: verifier.c

static int copy_verifier_state(struct bpf_verifier_state *dst_state,
			       const struct bpf_verifier_state *src)
{
	struct bpf_func_state *dst;
	u32 jmp_sz = sizeof(struct bpf_idx_pair) * src->jmp_history_cnt;
	int i, err;

	if (dst_state->jmp_history_cnt < src->jmp_history_cnt) {
		kfree(dst_state->jmp_history);
		dst_state->jmp_history = kmalloc(jmp_sz, GFP_USER);
		if (!dst_state->jmp_history)
			return -ENOMEM;
	}
	memcpy(dst_state->jmp_history, src->jmp_history, jmp_sz);
	dst_state->jmp_history_cnt = src->jmp_history_cnt;

	/* if dst has more stack frames then src frame, free them */
	for (i = src->curframe + 1; i <= dst_state->curframe; i++) {
		free_func_state(dst_state->frame[i]);
		dst_state->frame[i] = NULL;
	}
	dst_state->speculative = src->speculative;
	dst_state->curframe = src->curframe;
	dst_state->active_spin_lock = src->active_spin_lock;
	dst_state->branches = src->branches;
	dst_state->parent = src->parent;
	dst_state->first_insn_idx = src->first_insn_idx;
	dst_state->last_insn_idx = src->last_insn_idx;
	for (i = 0; i <= src->curframe; i++) {
		dst = dst_state->frame[i];
		if (!dst) {
			dst = kzalloc(sizeof(*dst), GFP_KERNEL);
			if (!dst)
				return -ENOMEM;
			dst_state->frame[i] = dst;
		}
		err = copy_func_state(dst, src->frame[i]);
		if (err)
			return err;
	}
	return 0;
}

Project: linux
File: verifier.c

static int check_generic_ptr_alignment(struct bpf_verifier_env *env,
				       const struct bpf_reg_state *reg,
				       const char *pointer_desc,
				       int off, int size, bool strict)
{
	struct tnum reg_off;

	/* Byte size accesses are always allowed. */
	if (!strict || size == 1)
		return 0;

	reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off));
	if (!tnum_is_aligned(reg_off, size)) {
		char tn_buf[48];

		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
		verbose(env, "misaligned %saccess off %s+%d+%d size %d\n",
			pointer_desc, tn_buf, reg->off, off, size);
		return -EACCES;
	}

	return 0;
}

Project: linux
File: verifier.c

static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
{
	return check_raw_mode_ok(fn) &&
	       check_arg_pair_ok(fn) &&
	       check_refcount_ok(fn, func_id) ? 0 : -EINVAL;
}

Project: linux
File: verifier.c

static void __reg_bound_offset(struct bpf_reg_state *reg)
{
	reg->var_off = tnum_intersect(reg->var_off,
				      tnum_range(reg->umin_value,
						 reg->umax_value));
}

Project: linux
File: verifier.c

void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt,
		       va_list args)
{
	unsigned int n;

	n = vscnprintf(log->kbuf, BPF_VERIFIER_TMP_LOG_SIZE, fmt, args);

	WARN_ONCE(n >= BPF_VERIFIER_TMP_LOG_SIZE - 1,
		  "verifier log line truncated - local buffer too short\n");

	n = min(log->len_total - log->len_used - 1, n);
	log->kbuf[n] = '\0';

	if (log->level == BPF_LOG_KERNEL) {
		pr_err("BPF:%s\n", log->kbuf);
		return;
	}
	if (!copy_to_user(log->ubuf + log->len_used, log->kbuf, n + 1))
		log->len_used += n;
	else
		log->ubuf = NULL;
}

Project: linux
File: verifier.c

static void free_verifier_state(struct bpf_verifier_state *state,
				bool free_self)
{
	int i;

	for (i = 0; i <= state->curframe; i++) {
		free_func_state(state->frame[i]);
		state->frame[i] = NULL;
	}
	clear_jmp_history(state);
	if (free_self)
		kfree(state);
}

Project: linux
File: verifier.c

static void init_explored_state(struct bpf_verifier_env *env, int idx)
{
	env->insn_aux_data[idx].prune_point = true;
}

Project: linux
File: verifier.c

static void scalar_min_max_and(struct bpf_reg_state *dst_reg,
			       struct bpf_reg_state *src_reg)
{
	s64 smin_val = src_reg->smin_value;
	u64 umax_val = src_reg->umax_value;

	/* We get our minimum from the var_off, since that's inherently
	 * bitwise.  Our maximum is the minimum of the operands' maxima.
	 */
	dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg->var_off);
	dst_reg->umin_value = dst_reg->var_off.value;
	dst_reg->umax_value = min(dst_reg->umax_value, umax_val);
	if (dst_reg->smin_value < 0 || smin_val < 0) {
		/* Lose signed bounds when ANDing negative numbers,
		 * ain't nobody got time for that.
		 */
		dst_reg->smin_value = S64_MIN;
		dst_reg->smax_value = S64_MAX;
	} else {
		/* ANDing two positives gives a positive, so safe to
		 * cast result into s64.
		 */
		dst_reg->smin_value = dst_reg->umin_value;
		dst_reg->smax_value = dst_reg->umax_value;
	}
	/* We may learn something more from the var_off */
	__update_reg_bounds(dst_reg);
}