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 adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
				   struct bpf_insn *insn,
				   const struct bpf_reg_state *ptr_reg,
				   const struct bpf_reg_state *off_reg)
{
	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;
	bool known = tnum_is_const(off_reg->var_off);
	s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value,
	    smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
	u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value,
	    umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value;
	u32 dst = insn->dst_reg, src = insn->src_reg;
	u8 opcode = BPF_OP(insn->code);
	int ret;

	dst_reg = &regs[dst];

	if ((known && (smin_val != smax_val || umin_val != umax_val)) ||
	    smin_val > smax_val || umin_val > umax_val) {
		/* Taint dst register if offset had invalid bounds derived from
		 * e.g. dead branches.
		 */
		__mark_reg_unknown(env, dst_reg);
		return 0;
	}

	if (BPF_CLASS(insn->code) != BPF_ALU64) {
		/* 32-bit ALU ops on pointers produce (meaningless) scalars */
		verbose(env,
			"R%d 32-bit pointer arithmetic prohibited\n",
			dst);
		return -EACCES;
	}

	switch (ptr_reg->type) {
	case PTR_TO_MAP_VALUE_OR_NULL:
		verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
			dst, reg_type_str[ptr_reg->type]);
		return -EACCES;
	case CONST_PTR_TO_MAP:
	case PTR_TO_PACKET_END:
	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:
		verbose(env, "R%d pointer arithmetic on %s prohibited\n",
			dst, reg_type_str[ptr_reg->type]);
		return -EACCES;
	case PTR_TO_MAP_VALUE:
		if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) {
			verbose(env, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n",
				off_reg == dst_reg ? dst : src);
			return -EACCES;
		}
		/* fall-through */
	default:
		break;
	}

	/* In case of 'scalar += pointer', dst_reg inherits pointer type and id.
	 * The id may be overwritten later if we create a new variable offset.
	 */
	dst_reg->type = ptr_reg->type;
	dst_reg->id = ptr_reg->id;

	if (!check_reg_sane_offset(env, off_reg, ptr_reg->type) ||
	    !check_reg_sane_offset(env, ptr_reg, ptr_reg->type))
		return -EINVAL;

	switch (opcode) {
	case BPF_ADD:
		ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0);
		if (ret < 0) {
			verbose(env, "R%d tried to add from different maps or paths\n", dst);
			return ret;
		}
		/* We can take a fixed offset as long as it doesn't overflow
		 * the s32 'off' field
		 */
		if (known && (ptr_reg->off + smin_val ==
			      (s64)(s32)(ptr_reg->off + smin_val))) {
			/* pointer += K.  Accumulate it into fixed offset */
			dst_reg->smin_value = smin_ptr;
			dst_reg->smax_value = smax_ptr;
			dst_reg->umin_value = umin_ptr;
			dst_reg->umax_value = umax_ptr;
			dst_reg->var_off = ptr_reg->var_off;
			dst_reg->off = ptr_reg->off + smin_val;
			dst_reg->raw = ptr_reg->raw;
			break;
		}
		/* A new variable offset is created.  Note that off_reg->off
		 * == 0, since it's a scalar.
		 * dst_reg gets the pointer type and since some positive
		 * integer value was added to the pointer, give it a new 'id'
		 * if it's a PTR_TO_PACKET.
		 * this creates a new 'base' pointer, off_reg (variable) gets
		 * added into the variable offset, and we copy the fixed offset
		 * from ptr_reg.
		 */
		if (signed_add_overflows(smin_ptr, smin_val) ||
		    signed_add_overflows(smax_ptr, smax_val)) {
			dst_reg->smin_value = S64_MIN;
			dst_reg->smax_value = S64_MAX;
		} else {
			dst_reg->smin_value = smin_ptr + smin_val;
			dst_reg->smax_value = smax_ptr + smax_val;
		}
		if (umin_ptr + umin_val < umin_ptr ||
		    umax_ptr + umax_val < umax_ptr) {
			dst_reg->umin_value = 0;
			dst_reg->umax_value = U64_MAX;
		} else {
			dst_reg->umin_value = umin_ptr + umin_val;
			dst_reg->umax_value = umax_ptr + umax_val;
		}
		dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off);
		dst_reg->off = ptr_reg->off;
		dst_reg->raw = ptr_reg->raw;
		if (reg_is_pkt_pointer(ptr_reg)) {
			dst_reg->id = ++env->id_gen;
			/* something was added to pkt_ptr, set range to zero */
			dst_reg->raw = 0;
		}
		break;
	case BPF_SUB:
		ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0);
		if (ret < 0) {
			verbose(env, "R%d tried to sub from different maps or paths\n", dst);
			return ret;
		}
		if (dst_reg == off_reg) {
			/* scalar -= pointer.  Creates an unknown scalar */
			verbose(env, "R%d tried to subtract pointer from scalar\n",
				dst);
			return -EACCES;
		}
		/* We don't allow subtraction from FP, because (according to
		 * test_verifier.c test "invalid fp arithmetic", JITs might not
		 * be able to deal with it.
		 */
		if (ptr_reg->type == PTR_TO_STACK) {
			verbose(env, "R%d subtraction from stack pointer prohibited\n",
				dst);
			return -EACCES;
		}
		if (known && (ptr_reg->off - smin_val ==
			      (s64)(s32)(ptr_reg->off - smin_val))) {
			/* pointer -= K.  Subtract it from fixed offset */
			dst_reg->smin_value = smin_ptr;
			dst_reg->smax_value = smax_ptr;
			dst_reg->umin_value = umin_ptr;
			dst_reg->umax_value = umax_ptr;
			dst_reg->var_off = ptr_reg->var_off;
			dst_reg->id = ptr_reg->id;
			dst_reg->off = ptr_reg->off - smin_val;
			dst_reg->raw = ptr_reg->raw;
			break;
		}
		/* A new variable offset is created.  If the subtrahend is known
		 * nonnegative, then any reg->range we had before is still good.
		 */
		if (signed_sub_overflows(smin_ptr, smax_val) ||
		    signed_sub_overflows(smax_ptr, smin_val)) {
			/* Overflow possible, we know nothing */
			dst_reg->smin_value = S64_MIN;
			dst_reg->smax_value = S64_MAX;
		} else {
			dst_reg->smin_value = smin_ptr - smax_val;
			dst_reg->smax_value = smax_ptr - smin_val;
		}
		if (umin_ptr < 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 = umin_ptr - umax_val;
			dst_reg->umax_value = umax_ptr - umin_val;
		}
		dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off);
		dst_reg->off = ptr_reg->off;
		dst_reg->raw = ptr_reg->raw;
		if (reg_is_pkt_pointer(ptr_reg)) {
			dst_reg->id = ++env->id_gen;
			/* something was added to pkt_ptr, set range to zero */
			if (smin_val < 0)
				dst_reg->raw = 0;
		}
		break;
	case BPF_AND:
	case BPF_OR:
	case BPF_XOR:
		/* bitwise ops on pointers are troublesome, prohibit. */
		verbose(env, "R%d bitwise operator %s on pointer prohibited\n",
			dst, bpf_alu_string[opcode >> 4]);
		return -EACCES;
	default:
		/* other operators (e.g. MUL,LSH) produce non-pointer results */
		verbose(env, "R%d pointer arithmetic with %s operator prohibited\n",
			dst, bpf_alu_string[opcode >> 4]);
		return -EACCES;
	}

	if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type))
		return -EINVAL;

	__update_reg_bounds(dst_reg);
	__reg_deduce_bounds(dst_reg);
	__reg_bound_offset(dst_reg);

	/* For unprivileged we require that resulting offset must be in bounds
	 * in order to be able to sanitize access later on.
	 */
	if (!env->allow_ptr_leaks) {
		if (dst_reg->type == PTR_TO_MAP_VALUE &&
		    check_map_access(env, dst, dst_reg->off, 1, false)) {
			verbose(env, "R%d pointer arithmetic of map value goes out of range, "
				"prohibited for !root\n", dst);
			return -EACCES;
		} else if (dst_reg->type == PTR_TO_STACK &&
			   check_stack_access(env, dst_reg, dst_reg->off +
					      dst_reg->var_off.value, 1)) {
			verbose(env, "R%d stack pointer arithmetic goes out of range, "
				"prohibited for !root\n", dst);
			return -EACCES;
		}
	}

	return 0;
}

Project: linux
File: verifier.c

static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
{
	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
	unsigned int orig_prog_len = env->prog->len;
	int err;

	if (bpf_prog_is_dev_bound(env->prog->aux))
		bpf_prog_offload_remove_insns(env, off, cnt);

	err = bpf_remove_insns(env->prog, off, cnt);
	if (err)
		return err;

	err = adjust_subprog_starts_after_remove(env, off, cnt);
	if (err)
		return err;

	err = bpf_adj_linfo_after_remove(env, off, cnt);
	if (err)
		return err;

	memmove(aux_data + off,	aux_data + off + cnt,
		sizeof(*aux_data) * (orig_prog_len - off - cnt));

	return 0;
}

Project: linux
File: verifier.c

static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
				   int func_id,
				   struct bpf_call_arg_meta *meta)
{
	struct bpf_reg_state *ret_reg = &regs[BPF_REG_0];

	if (ret_type != RET_INTEGER ||
	    (func_id != BPF_FUNC_get_stack &&
	     func_id != BPF_FUNC_probe_read_str))
		return;

	ret_reg->smax_value = meta->msize_smax_value;
	ret_reg->umax_value = meta->msize_umax_value;
	__reg_deduce_bounds(ret_reg);
	__reg_bound_offset(ret_reg);
}

Project: linux
File: verifier.c

static void scalar_min_max_mul(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;
	u64 umax_val = src_reg->umax_value;

	dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg->var_off);
	if (smin_val < 0 || dst_reg->smin_value < 0) {
		/* Ain't nobody got time to multiply that sign */
		__mark_reg_unbounded(dst_reg);
		__update_reg_bounds(dst_reg);
		return;
	}
	/* Both values are positive, so we can work with unsigned and
	 * copy the result to signed (unless it exceeds S64_MAX).
	 */
	if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) {
		/* Potential overflow, we know nothing */
		__mark_reg_unbounded(dst_reg);
		/* (except what we can learn from the var_off) */
		__update_reg_bounds(dst_reg);
		return;
	}
	dst_reg->umin_value *= umin_val;
	dst_reg->umax_value *= umax_val;
	if (dst_reg->umax_value > S64_MAX) {
		/* Overflow possible, we know nothing */
		dst_reg->smin_value = S64_MIN;
		dst_reg->smax_value = S64_MAX;
	} else {
		dst_reg->smin_value = dst_reg->umin_value;
		dst_reg->smax_value = dst_reg->umax_value;
	}
}

Project: linux
File: verifier.c

static int adjust_insn_aux_data(struct bpf_verifier_env *env,
				struct bpf_prog *new_prog, u32 off, u32 cnt)
{
	struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data;
	struct bpf_insn *insn = new_prog->insnsi;
	u32 prog_len;
	int i;

	/* aux info at OFF always needs adjustment, no matter fast path
	 * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the
	 * original insn at old prog.
	 */
	old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1);

	if (cnt == 1)
		return 0;
	prog_len = new_prog->len;
	new_data = vzalloc(array_size(prog_len,
				      sizeof(struct bpf_insn_aux_data)));
	if (!new_data)
		return -ENOMEM;
	memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off);
	memcpy(new_data + off + cnt - 1, old_data + off,
	       sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
	for (i = off; i < off + cnt - 1; i++) {
		new_data[i].seen = env->pass_cnt;
		new_data[i].zext_dst = insn_has_def32(env, insn + i);
	}
	env->insn_aux_data = new_data;
	vfree(old_data);
	return 0;
}

Project: linux
File: verifier.c

static int check_flow_keys_access(struct bpf_verifier_env *env, int off,
				  int size)
{
	if (size < 0 || off < 0 ||
	    (u64)off + size > sizeof(struct bpf_flow_keys)) {
		verbose(env, "invalid access to flow keys off=%d size=%d\n",
			off, size);
		return -EACCES;
	}
	return 0;
}

Project: linux
File: verifier.c

int check_ctx_reg(struct bpf_verifier_env *env,
		  const struct bpf_reg_state *reg, int regno)
{
	/* Access to ctx or passing it to a helper is only allowed in
	 * its original, unmodified form.
	 */

	if (reg->off) {
		verbose(env, "dereference of modified ctx ptr R%d off=%d disallowed\n",
			regno, reg->off);
		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, "variable ctx access var_off=%s disallowed\n", tn_buf);
		return -EACCES;
	}

	return 0;
}

Project: linux
File: verifier.c

static void __update_reg_bounds(struct bpf_reg_state *reg)
{
	/* min signed is max(sign bit) | min(other bits) */
	reg->smin_value = max_t(s64, reg->smin_value,
				reg->var_off.value | (reg->var_off.mask & S64_MIN));
	/* max signed is min(sign bit) | max(other bits) */
	reg->smax_value = min_t(s64, reg->smax_value,
				reg->var_off.value | (reg->var_off.mask & S64_MAX));
	reg->umin_value = max(reg->umin_value, reg->var_off.value);
	reg->umax_value = min(reg->umax_value,
			      reg->var_off.value | reg->var_off.mask);
}

Project: linux
File: verifier.c

static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
				   struct bpf_reg_state *regs,
				   int regno, int off, int size,
				   enum bpf_access_type atype,
				   int value_regno)
{
	struct bpf_reg_state *reg = regs + regno;
	const struct btf_type *t = btf_type_by_id(btf_vmlinux, reg->btf_id);
	const char *tname = btf_name_by_offset(btf_vmlinux, t->name_off);
	u32 btf_id;
	int ret;

	if (off < 0) {
		verbose(env,
			"R%d is ptr_%s invalid negative access: off=%d\n",
			regno, tname, off);
		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 is ptr_%s invalid variable offset: off=%d, var_off=%s\n",
			regno, tname, off, tn_buf);
		return -EACCES;
	}

	if (env->ops->btf_struct_access) {
		ret = env->ops->btf_struct_access(&env->log, t, off, size,
						  atype, &btf_id);
	} else {
		if (atype != BPF_READ) {
			verbose(env, "only read is supported\n");
			return -EACCES;
		}

		ret = btf_struct_access(&env->log, t, off, size, atype,
					&btf_id);
	}

	if (ret < 0)
		return ret;

	if (atype == BPF_READ) {
		if (ret == SCALAR_VALUE) {
			mark_reg_unknown(env, regs, value_regno);
			return 0;
		}
		mark_reg_known_zero(env, regs, value_regno);
		regs[value_regno].type = PTR_TO_BTF_ID;
		regs[value_regno].btf_id = btf_id;
	}

	return 0;
}

Project: linux
File: verifier.c

static bool signed_add_overflows(s64 a, s64 b)
{
	/* Do the add 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 bool is_pointer_value(struct bpf_verifier_env *env, int regno)
{
	return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno));
}

Project: linux
File: verifier.c

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

	/* If the dst_reg is a pointer, we can't learn anything about its
	 * variable offset from the compare (unless src_reg were a pointer into
	 * the same object, but we don't bother with that.
	 * Since false_reg and true_reg have the same type by construction, we
	 * only need to check one of them for pointerness.
	 */
	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;

		/* For BPF_JEQ, if this is false we know nothing Jon Snow, but
		 * if it is true we know the value for sure. Likewise for
		 * BPF_JNE.
		 */
		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_umax = opcode == BPF_JGT ? val    : val - 1;
		u64 true_umin = opcode == BPF_JGT ? 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_JSGE:
	case BPF_JSGT:
	{
		s64 false_smax = opcode == BPF_JSGT ? sval    : sval - 1;
		s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval;

		/* If the full s64 was not sign-extended from s32 then don't
		 * deduct further info.
		 */
		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;
	}
	case BPF_JLE:
	case BPF_JLT:
	{
		u64 false_umin = opcode == BPF_JLT ? val    : val + 1;
		u64 true_umax = opcode == BPF_JLT ? 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_JSLE:
	case BPF_JSLT:
	{
		s64 false_smin = opcode == BPF_JSLT ? sval    : sval + 1;
		s64 true_smax = opcode == BPF_JSLT ? 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;
	}
	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 bool is_sk_reg(struct bpf_verifier_env *env, int regno)
{
	const struct bpf_reg_state *reg = reg_state(env, regno);

	return type_is_sk_pointer(reg->type);
}

Project: linux
File: verifier.c

static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno,
				  bool is_null)
{
	struct bpf_func_state *state = vstate->frame[vstate->curframe];
	struct bpf_reg_state *regs = state->regs;
	u32 ref_obj_id = regs[regno].ref_obj_id;
	u32 id = regs[regno].id;
	int i;

	if (ref_obj_id && ref_obj_id == id && is_null)
		/* regs[regno] is in the " == NULL" branch.
		 * No one could have freed the reference state before
		 * doing the NULL check.
		 */
		WARN_ON_ONCE(release_reference_state(state, id));

	for (i = 0; i <= vstate->curframe; i++)
		__mark_ptr_or_null_regs(vstate->frame[i], id, is_null);
}

Project: linux
File: verifier.c

static int mark_reg_read(struct bpf_verifier_env *env,
			 const struct bpf_reg_state *state,
			 struct bpf_reg_state *parent, u8 flag)
{
	bool writes = parent == state->parent; /* Observe write marks */
	int cnt = 0;

	while (parent) {
		/* if read wasn't screened by an earlier write ... */
		if (writes && state->live & REG_LIVE_WRITTEN)
			break;
		if (parent->live & REG_LIVE_DONE) {
			verbose(env, "verifier BUG type %s var_off %lld off %d\n",
				reg_type_str[parent->type],
				parent->var_off.value, parent->off);
			return -EFAULT;
		}
		/* The first condition is more likely to be true than the
		 * second, checked it first.
		 */
		if ((parent->live & REG_LIVE_READ) == flag ||
		    parent->live & REG_LIVE_READ64)
			/* The parentage chain never changes and
			 * this parent was already marked as LIVE_READ.
			 * There is no need to keep walking the chain again and
			 * keep re-marking all parents as LIVE_READ.
			 * This case happens when the same register is read
			 * multiple times without writes into it in-between.
			 * Also, if parent has the stronger REG_LIVE_READ64 set,
			 * then no need to set the weak REG_LIVE_READ32.
			 */
			break;
		/* ... then we depend on parent's value */
		parent->live |= flag;
		/* REG_LIVE_READ64 overrides REG_LIVE_READ32. */
		if (flag == REG_LIVE_READ64)
			parent->live &= ~REG_LIVE_READ32;
		state = parent;
		parent = state->parent;
		writes = true;
		cnt++;
	}

	if (env->longest_mark_read_walk < cnt)
		env->longest_mark_read_walk = cnt;
	return 0;
}

Project: linux
File: verifier.c

static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn,
		     u32 regno, struct bpf_reg_state *reg, enum reg_arg_type t)
{
	u8 code, class, op;

	code = insn->code;
	class = BPF_CLASS(code);
	op = BPF_OP(code);
	if (class == BPF_JMP) {
		/* BPF_EXIT for "main" will reach here. Return TRUE
		 * conservatively.
		 */
		if (op == BPF_EXIT)
			return true;
		if (op == BPF_CALL) {
			/* BPF to BPF call will reach here because of marking
			 * caller saved clobber with DST_OP_NO_MARK for which we
			 * don't care the register def because they are anyway
			 * marked as NOT_INIT already.
			 */
			if (insn->src_reg == BPF_PSEUDO_CALL)
				return false;
			/* Helper call will reach here because of arg type
			 * check, conservatively return TRUE.
			 */
			if (t == SRC_OP)
				return true;

			return false;
		}
	}

	if (class == BPF_ALU64 || class == BPF_JMP ||
	    /* BPF_END always use BPF_ALU class. */
	    (class == BPF_ALU && op == BPF_END && insn->imm == 64))
		return true;

	if (class == BPF_ALU || class == BPF_JMP32)
		return false;

	if (class == BPF_LDX) {
		if (t != SRC_OP)
			return BPF_SIZE(code) == BPF_DW;
		/* LDX source must be ptr. */
		return true;
	}

	if (class == BPF_STX) {
		if (reg->type != SCALAR_VALUE)
			return true;
		return BPF_SIZE(code) == BPF_DW;
	}

	if (class == BPF_LD) {
		u8 mode = BPF_MODE(code);

		/* LD_IMM64 */
		if (mode == BPF_IMM)
			return true;

		/* Both LD_IND and LD_ABS return 32-bit data. */
		if (t != SRC_OP)
			return  false;

		/* Implicit ctx ptr. */
		if (regno == BPF_REG_6)
			return true;

		/* Explicit source could be any width. */
		return true;
	}

	if (class == BPF_ST)
		/* The only source register for BPF_ST is a ptr. */
		return true;

	/* Conservatively return true at default. */
	return true;
}

Project: linux
File: verifier.c

static int fixup_call_args(struct bpf_verifier_env *env)
{
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
	struct bpf_prog *prog = env->prog;
	struct bpf_insn *insn = prog->insnsi;
	int i, depth;
#endif
	int err = 0;

	if (env->prog->jit_requested &&
	    !bpf_prog_is_dev_bound(env->prog->aux)) {
		err = jit_subprogs(env);
		if (err == 0)
			return 0;
		if (err == -EFAULT)
			return err;
	}
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
	for (i = 0; i < prog->len; i++, insn++) {
		if (insn->code != (BPF_JMP | BPF_CALL) ||
		    insn->src_reg != BPF_PSEUDO_CALL)
			continue;
		depth = get_callee_stack_depth(env, insn, i);
		if (depth < 0)
			return depth;
		bpf_patch_call_args(insn, depth);
	}
	err = 0;
#endif
	return err;
}

Project: linux
File: verifier.c

static bool arg_type_is_int_ptr(enum bpf_arg_type type)
{
	return type == ARG_PTR_TO_INT ||
	       type == ARG_PTR_TO_LONG;
}

Project: linux
File: verifier.c

static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg,
				    enum bpf_reg_type which)
{
	/* The register can already have a range from prior markings.
	 * This is fine as long as it hasn't been advanced from its
	 * origin.
	 */
	return reg->type == which &&
	       reg->id == 0 &&
	       reg->off == 0 &&
	       tnum_equals_const(reg->var_off, 0);
}

Project: linux
File: verifier.c

static bool cmp_val_with_extended_s64(s64 sval, struct bpf_reg_state *reg)
{
	return ((s32)sval >= 0 &&
		reg->smin_value >= 0 && reg->smax_value <= S32_MAX) ||
	       ((s32)sval < 0 &&
		reg->smax_value <= 0 && reg->smin_value >= S32_MIN);
}

Project: linux
File: verifier.c

static int check_attach_modify_return(struct bpf_verifier_env *env)
{
	struct bpf_prog *prog = env->prog;
	unsigned long addr = (unsigned long) prog->aux->trampoline->func.addr;

	/* This is expected to be cleaned up in the future with the KRSI effort
	 * introducing the LSM_HOOK macro for cleaning up lsm_hooks.h.
	 */
	if (within_error_injection_list(addr) ||
	    !strncmp(SECURITY_PREFIX, prog->aux->attach_func_name,
		     sizeof(SECURITY_PREFIX) - 1))
		return 0;

	verbose(env, "fmod_ret attach_btf_id %u (%s) is not modifiable\n",
		prog->aux->attach_btf_id, prog->aux->attach_func_name);

	return -EINVAL;
}

Project: linux
File: verifier.c

static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm)
{
	/* Clear id, off, and union(map_ptr, range) */
	memset(((u8 *)reg) + sizeof(reg->type), 0,
	       offsetof(struct bpf_reg_state, var_off) - sizeof(reg->type));
	reg->var_off = tnum_const(imm);
	reg->smin_value = (s64)imm;
	reg->smax_value = (s64)imm;
	reg->umin_value = imm;
	reg->umax_value = imm;
}

Project: linux
File: verifier.c

static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno,
			    int off, int bpf_size, enum bpf_access_type t,
			    int value_regno, bool strict_alignment_once)
{
	struct bpf_reg_state *regs = cur_regs(env);
	struct bpf_reg_state *reg = regs + regno;
	struct bpf_func_state *state;
	int size, err = 0;

	size = bpf_size_to_bytes(bpf_size);
	if (size < 0)
		return size;

	/* alignment checks will add in reg->off themselves */
	err = check_ptr_alignment(env, reg, off, size, strict_alignment_once);
	if (err)
		return err;

	/* for access checks, reg->off is just part of off */
	off += reg->off;

	if (reg->type == PTR_TO_MAP_VALUE) {
		if (t == BPF_WRITE && value_regno >= 0 &&
		    is_pointer_value(env, value_regno)) {
			verbose(env, "R%d leaks addr into map\n", value_regno);
			return -EACCES;
		}
		err = check_map_access_type(env, regno, off, size, t);
		if (err)
			return err;
		err = check_map_access(env, regno, off, size, false);
		if (!err && t == BPF_READ && value_regno >= 0) {
			struct bpf_map *map = reg->map_ptr;

			/* if map is read-only, track its contents as scalars */
			if (tnum_is_const(reg->var_off) &&
			    bpf_map_is_rdonly(map) &&
			    map->ops->map_direct_value_addr) {
				int map_off = off + reg->var_off.value;
				u64 val = 0;

				err = bpf_map_direct_read(map, map_off, size,
							  &val);
				if (err)
					return err;

				regs[value_regno].type = SCALAR_VALUE;
				__mark_reg_known(&regs[value_regno], val);
			} else {
				mark_reg_unknown(env, regs, value_regno);
			}
		}
	} else if (reg->type == PTR_TO_CTX) {
		enum bpf_reg_type reg_type = SCALAR_VALUE;
		u32 btf_id = 0;

		if (t == BPF_WRITE && value_regno >= 0 &&
		    is_pointer_value(env, value_regno)) {
			verbose(env, "R%d leaks addr into ctx\n", value_regno);
			return -EACCES;
		}

		err = check_ctx_reg(env, reg, regno);
		if (err < 0)
			return err;

		err = check_ctx_access(env, insn_idx, off, size, t, &reg_type, &btf_id);
		if (err)
			verbose_linfo(env, insn_idx, "; ");
		if (!err && t == BPF_READ && value_regno >= 0) {
			/* ctx access returns either a scalar, or a
			 * PTR_TO_PACKET[_META,_END]. In the latter
			 * case, we know the offset is zero.
			 */
			if (reg_type == SCALAR_VALUE) {
				mark_reg_unknown(env, regs, value_regno);
			} else {
				mark_reg_known_zero(env, regs,
						    value_regno);
				if (reg_type_may_be_null(reg_type))
					regs[value_regno].id = ++env->id_gen;
				/* A load of ctx field could have different
				 * actual load size with the one encoded in the
				 * insn. When the dst is PTR, it is for sure not
				 * a sub-register.
				 */
				regs[value_regno].subreg_def = DEF_NOT_SUBREG;
				if (reg_type == PTR_TO_BTF_ID)
					regs[value_regno].btf_id = btf_id;
			}
			regs[value_regno].type = reg_type;
		}

	} else if (reg->type == PTR_TO_STACK) {
		off += reg->var_off.value;
		err = check_stack_access(env, reg, off, size);
		if (err)
			return err;

		state = func(env, reg);
		err = update_stack_depth(env, state, off);
		if (err)
			return err;

		if (t == BPF_WRITE)
			err = check_stack_write(env, state, off, size,
						value_regno, insn_idx);
		else
			err = check_stack_read(env, state, off, size,
					       value_regno);
	} else if (reg_is_pkt_pointer(reg)) {
		if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) {
			verbose(env, "cannot write into packet\n");
			return -EACCES;
		}
		if (t == BPF_WRITE && value_regno >= 0 &&
		    is_pointer_value(env, value_regno)) {
			verbose(env, "R%d leaks addr into packet\n",
				value_regno);
			return -EACCES;
		}
		err = check_packet_access(env, regno, off, size, false);
		if (!err && t == BPF_READ && value_regno >= 0)
			mark_reg_unknown(env, regs, value_regno);
	} else if (reg->type == PTR_TO_FLOW_KEYS) {
		if (t == BPF_WRITE && value_regno >= 0 &&
		    is_pointer_value(env, value_regno)) {
			verbose(env, "R%d leaks addr into flow keys\n",
				value_regno);
			return -EACCES;
		}

		err = check_flow_keys_access(env, off, size);
		if (!err && t == BPF_READ && value_regno >= 0)
			mark_reg_unknown(env, regs, value_regno);
	} else if (type_is_sk_pointer(reg->type)) {
		if (t == BPF_WRITE) {
			verbose(env, "R%d cannot write into %s\n",
				regno, reg_type_str[reg->type]);
			return -EACCES;
		}
		err = check_sock_access(env, insn_idx, regno, off, size, t);
		if (!err && value_regno >= 0)
			mark_reg_unknown(env, regs, value_regno);
	} else if (reg->type == PTR_TO_TP_BUFFER) {
		err = check_tp_buffer_access(env, reg, regno, off, size);
		if (!err && t == BPF_READ && value_regno >= 0)
			mark_reg_unknown(env, regs, value_regno);
	} else if (reg->type == PTR_TO_BTF_ID) {
		err = check_ptr_to_btf_access(env, regs, regno, off, size, t,
					      value_regno);
	} else {
		verbose(env, "R%d invalid mem access '%s'\n", regno,
			reg_type_str[reg->type]);
		return -EACCES;
	}

	if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ &&
	    regs[value_regno].type == SCALAR_VALUE) {
		/* b/h/w load zero-extends, mark upper bits as known 0 */
		coerce_reg_to_size(&regs[value_regno], size);
	}
	return err;
}

Project: linux
File: verifier.c

static void print_verifier_state(struct bpf_verifier_env *env,
				 const struct bpf_func_state *state)
{
	const struct bpf_reg_state *reg;
	enum bpf_reg_type t;
	int i;

	if (state->frameno)
		verbose(env, " frame%d:", state->frameno);
	for (i = 0; i < MAX_BPF_REG; i++) {
		reg = &state->regs[i];
		t = reg->type;
		if (t == NOT_INIT)
			continue;
		verbose(env, " R%d", i);
		print_liveness(env, reg->live);
		verbose(env, "=%s", reg_type_str[t]);
		if (t == SCALAR_VALUE && reg->precise)
			verbose(env, "P");
		if ((t == SCALAR_VALUE || t == PTR_TO_STACK) &&
		    tnum_is_const(reg->var_off)) {
			/* reg->off should be 0 for SCALAR_VALUE */
			verbose(env, "%lld", reg->var_off.value + reg->off);
		} else {
			if (t == PTR_TO_BTF_ID)
				verbose(env, "%s", kernel_type_name(reg->btf_id));
			verbose(env, "(id=%d", reg->id);
			if (reg_type_may_be_refcounted_or_null(t))
				verbose(env, ",ref_obj_id=%d", reg->ref_obj_id);
			if (t != SCALAR_VALUE)
				verbose(env, ",off=%d", reg->off);
			if (type_is_pkt_pointer(t))
				verbose(env, ",r=%d", reg->range);
			else if (t == CONST_PTR_TO_MAP ||
				 t == PTR_TO_MAP_VALUE ||
				 t == PTR_TO_MAP_VALUE_OR_NULL)
				verbose(env, ",ks=%d,vs=%d",
					reg->map_ptr->key_size,
					reg->map_ptr->value_size);
			if (tnum_is_const(reg->var_off)) {
				/* Typically an immediate SCALAR_VALUE, but
				 * could be a pointer whose offset is too big
				 * for reg->off
				 */
				verbose(env, ",imm=%llx", reg->var_off.value);
			} else {
				if (reg->smin_value != reg->umin_value &&
				    reg->smin_value != S64_MIN)
					verbose(env, ",smin_value=%lld",
						(long long)reg->smin_value);
				if (reg->smax_value != reg->umax_value &&
				    reg->smax_value != S64_MAX)
					verbose(env, ",smax_value=%lld",
						(long long)reg->smax_value);
				if (reg->umin_value != 0)
					verbose(env, ",umin_value=%llu",
						(unsigned long long)reg->umin_value);
				if (reg->umax_value != U64_MAX)
					verbose(env, ",umax_value=%llu",
						(unsigned long long)reg->umax_value);
				if (!tnum_is_unknown(reg->var_off)) {
					char tn_buf[48];

					tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
					verbose(env, ",var_off=%s", tn_buf);
				}
			}
			verbose(env, ")");
		}
	}
	for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
		char types_buf[BPF_REG_SIZE + 1];
		bool valid = false;
		int j;

		for (j = 0; j < BPF_REG_SIZE; j++) {
			if (state->stack[i].slot_type[j] != STACK_INVALID)
				valid = true;
			types_buf[j] = slot_type_char[
					state->stack[i].slot_type[j]];
		}
		types_buf[BPF_REG_SIZE] = 0;
		if (!valid)
			continue;
		verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
		print_liveness(env, state->stack[i].spilled_ptr.live);
		if (state->stack[i].slot_type[0] == STACK_SPILL) {
			reg = &state->stack[i].spilled_ptr;
			t = reg->type;
			verbose(env, "=%s", reg_type_str[t]);
			if (t == SCALAR_VALUE && reg->precise)
				verbose(env, "P");
			if (t == SCALAR_VALUE && tnum_is_const(reg->var_off))
				verbose(env, "%lld", reg->var_off.value + reg->off);
		} else {
			verbose(env, "=%s", types_buf);
		}
	}
	if (state->acquired_refs && state->refs[0].id) {
		verbose(env, " refs=%d", state->refs[0].id);
		for (i = 1; i < state->acquired_refs; i++)
			if (state->refs[i].id)
				verbose(env, ",%d", state->refs[i].id);
	}
	verbose(env, "\n");
}

Project: linux
File: verifier.c

static int opt_remove_dead_code(struct bpf_verifier_env *env)
{
	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
	int insn_cnt = env->prog->len;
	int i, err;

	for (i = 0; i < insn_cnt; i++) {
		int j;

		j = 0;
		while (i + j < insn_cnt && !aux_data[i + j].seen)
			j++;
		if (!j)
			continue;

		err = verifier_remove_insns(env, i, j);
		if (err)
			return err;
		insn_cnt = env->prog->len;
	}

	return 0;
}

Project: linux
File: verifier.c

static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
{
	while (st) {
		u32 br = --st->branches;

		/* WARN_ON(br > 1) technically makes sense here,
		 * but see comment in push_stack(), hence:
		 */
		WARN_ONCE((int)br < 0,
			  "BUG update_branch_counts:branches_to_explore=%d\n",
			  br);
		if (br)
			break;
		st = st->parent;
	}
}

Project: linux
File: verifier.c

static void __mark_ptr_or_null_regs(struct bpf_func_state *state, u32 id,
				    bool is_null)
{
	struct bpf_reg_state *reg;
	int i;

	for (i = 0; i < MAX_BPF_REG; i++)
		mark_ptr_or_null_reg(state, &state->regs[i], id, is_null);

	bpf_for_each_spilled_reg(i, state, reg) {
		if (!reg)
			continue;
		mark_ptr_or_null_reg(state, reg, id, is_null);
	}
}

Project: linux
File: verifier.c

static int propagate_precision(struct bpf_verifier_env *env,
			       const struct bpf_verifier_state *old)
{
	struct bpf_reg_state *state_reg;
	struct bpf_func_state *state;
	int i, err = 0;

	state = old->frame[old->curframe];
	state_reg = state->regs;
	for (i = 0; i < BPF_REG_FP; i++, state_reg++) {
		if (state_reg->type != SCALAR_VALUE ||
		    !state_reg->precise)
			continue;
		if (env->log.level & BPF_LOG_LEVEL2)
			verbose(env, "propagating r%d\n", i);
		err = mark_chain_precision(env, i);
		if (err < 0)
			return err;
	}

	for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
		if (state->stack[i].slot_type[0] != STACK_SPILL)
			continue;
		state_reg = &state->stack[i].spilled_ptr;
		if (state_reg->type != SCALAR_VALUE ||
		    !state_reg->precise)
			continue;
		if (env->log.level & BPF_LOG_LEVEL2)
			verbose(env, "propagating fp%d\n",
				(-i - 1) * BPF_REG_SIZE);
		err = mark_chain_precision_stack(env, i);
		if (err < 0)
			return err;
	}
	return 0;
}

Project: linux
File: verifier.c

static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env)
{
	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
	struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
	struct bpf_insn *insn = env->prog->insnsi;
	const int insn_cnt = env->prog->len;
	int i;

	for (i = 0; i < insn_cnt; i++, insn++) {
		if (!insn_is_cond_jump(insn->code))
			continue;

		if (!aux_data[i + 1].seen)
			ja.off = insn->off;
		else if (!aux_data[i + 1 + insn->off].seen)
			ja.off = 0;
		else
			continue;

		if (bpf_prog_is_dev_bound(env->prog->aux))
			bpf_prog_offload_replace_insn(env, i, &ja);

		memcpy(insn, &ja, sizeof(ja));
	}
}

Project: linux
File: verifier.c

static int check_stack_access(struct bpf_verifier_env *env,
			      const struct bpf_reg_state *reg,
			      int off, int size)
{
	/* Stack accesses must be at a fixed offset, so that we
	 * can determine what type of data were returned. See
	 * check_stack_read().
	 */
	if (!tnum_is_const(reg->var_off)) {
		char tn_buf[48];

		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
		verbose(env, "variable stack access var_off=%s off=%d size=%d\n",
			tn_buf, off, size);
		return -EACCES;
	}

	if (off >= 0 || off < -MAX_BPF_STACK) {
		verbose(env, "invalid stack off=%d size=%d\n", off, size);
		return -EACCES;
	}

	return 0;
}

Project: linux
File: verifier.c

static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx)
{
	const struct bpf_func_proto *fn = NULL;
	struct bpf_reg_state *regs;
	struct bpf_call_arg_meta meta;
	bool changes_data;
	int i, err;

	/* find function prototype */
	if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) {
		verbose(env, "invalid func %s#%d\n", func_id_name(func_id),
			func_id);
		return -EINVAL;
	}

	if (env->ops->get_func_proto)
		fn = env->ops->get_func_proto(func_id, env->prog);
	if (!fn) {
		verbose(env, "unknown func %s#%d\n", func_id_name(func_id),
			func_id);
		return -EINVAL;
	}

	/* eBPF programs must be GPL compatible to use GPL-ed functions */
	if (!env->prog->gpl_compatible && fn->gpl_only) {
		verbose(env, "cannot call GPL-restricted function from non-GPL compatible program\n");
		return -EINVAL;
	}

	/* With LD_ABS/IND some JITs save/restore skb from r1. */
	changes_data = bpf_helper_changes_pkt_data(fn->func);
	if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {
		verbose(env, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n",
			func_id_name(func_id), func_id);
		return -EINVAL;
	}

	memset(&meta, 0, sizeof(meta));
	meta.pkt_access = fn->pkt_access;

	err = check_func_proto(fn, func_id);
	if (err) {
		verbose(env, "kernel subsystem misconfigured func %s#%d\n",
			func_id_name(func_id), func_id);
		return err;
	}

	meta.func_id = func_id;
	/* check args */
	for (i = 0; i < 5; i++) {
		err = btf_resolve_helper_id(&env->log, fn, i);
		if (err > 0)
			meta.btf_id = err;
		err = check_func_arg(env, BPF_REG_1 + i, fn->arg_type[i], &meta);
		if (err)
			return err;
	}

	err = record_func_map(env, &meta, func_id, insn_idx);
	if (err)
		return err;

	err = record_func_key(env, &meta, func_id, insn_idx);
	if (err)
		return err;

	/* Mark slots with STACK_MISC in case of raw mode, stack offset
	 * is inferred from register state.
	 */
	for (i = 0; i < meta.access_size; i++) {
		err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
				       BPF_WRITE, -1, false);
		if (err)
			return err;
	}

	if (func_id == BPF_FUNC_tail_call) {
		err = check_reference_leak(env);
		if (err) {
			verbose(env, "tail_call would lead to reference leak\n");
			return err;
		}
	} else if (is_release_function(func_id)) {
		err = release_reference(env, meta.ref_obj_id);
		if (err) {
			verbose(env, "func %s#%d reference has not been acquired before\n",
				func_id_name(func_id), func_id);
			return err;
		}
	}

	regs = cur_regs(env);

	/* check that flags argument in get_local_storage(map, flags) is 0,
	 * this is required because get_local_storage() can't return an error.
	 */
	if (func_id == BPF_FUNC_get_local_storage &&
	    !register_is_null(&regs[BPF_REG_2])) {
		verbose(env, "get_local_storage() doesn't support non-zero flags\n");
		return -EINVAL;
	}

	/* reset caller saved regs */
	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);
	}

	/* helper call returns 64-bit value. */
	regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;

	/* update return register (already marked as written above) */
	if (fn->ret_type == RET_INTEGER) {
		/* sets type to SCALAR_VALUE */
		mark_reg_unknown(env, regs, BPF_REG_0);
	} else if (fn->ret_type == RET_VOID) {
		regs[BPF_REG_0].type = NOT_INIT;
	} else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL ||
		   fn->ret_type == RET_PTR_TO_MAP_VALUE) {
		/* There is no offset yet applied, variable or fixed */
		mark_reg_known_zero(env, regs, BPF_REG_0);
		/* remember map_ptr, so that check_map_access()
		 * can check 'value_size' boundary of memory access
		 * to map element returned from bpf_map_lookup_elem()
		 */
		if (meta.map_ptr == NULL) {
			verbose(env,
				"kernel subsystem misconfigured verifier\n");
			return -EINVAL;
		}
		regs[BPF_REG_0].map_ptr = meta.map_ptr;
		if (fn->ret_type == RET_PTR_TO_MAP_VALUE) {
			regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;
			if (map_value_has_spin_lock(meta.map_ptr))
				regs[BPF_REG_0].id = ++env->id_gen;
		} else {
			regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
			regs[BPF_REG_0].id = ++env->id_gen;
		}
	} else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) {
		mark_reg_known_zero(env, regs, BPF_REG_0);
		regs[BPF_REG_0].type = PTR_TO_SOCKET_OR_NULL;
		regs[BPF_REG_0].id = ++env->id_gen;
	} else if (fn->ret_type == RET_PTR_TO_SOCK_COMMON_OR_NULL) {
		mark_reg_known_zero(env, regs, BPF_REG_0);
		regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON_OR_NULL;
		regs[BPF_REG_0].id = ++env->id_gen;
	} else if (fn->ret_type == RET_PTR_TO_TCP_SOCK_OR_NULL) {
		mark_reg_known_zero(env, regs, BPF_REG_0);
		regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL;
		regs[BPF_REG_0].id = ++env->id_gen;
	} else {
		verbose(env, "unknown return type %d of func %s#%d\n",
			fn->ret_type, func_id_name(func_id), func_id);
		return -EINVAL;
	}

	if (is_ptr_cast_function(func_id)) {
		/* For release_reference() */
		regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
	} else if (is_acquire_function(func_id)) {
		int id = acquire_reference_state(env, insn_idx);

		if (id < 0)
			return id;
		/* For mark_ptr_or_null_reg() */
		regs[BPF_REG_0].id = id;
		/* For release_reference() */
		regs[BPF_REG_0].ref_obj_id = id;
	}

	do_refine_retval_range(regs, fn->ret_type, func_id, &meta);

	err = check_map_func_compatibility(env, meta.map_ptr, func_id);
	if (err)
		return err;

	if (func_id == BPF_FUNC_get_stack && !env->prog->has_callchain_buf) {
		const char *err_str;

#ifdef CONFIG_PERF_EVENTS
		err = get_callchain_buffers(sysctl_perf_event_max_stack);
		err_str = "cannot get callchain buffer for func %s#%d\n";
#else
		err = -ENOTSUPP;
		err_str = "func %s#%d not supported without CONFIG_PERF_EVENTS\n";
#endif
		if (err) {
			verbose(env, err_str, func_id_name(func_id), func_id);
			return err;
		}

		env->prog->has_callchain_buf = true;
	}

	if (changes_data)
		clear_all_pkt_pointers(env);
	return 0;
}

Project: linux
File: verifier.c

static void __mark_reg_unbounded(struct bpf_reg_state *reg)
{
	reg->smin_value = S64_MIN;
	reg->smax_value = S64_MAX;
	reg->umin_value = 0;
	reg->umax_value = U64_MAX;
}

Project: linux
File: verifier.c

static int backtrack_insn(struct bpf_verifier_env *env, int idx,
			  u32 *reg_mask, u64 *stack_mask)
{
	const struct bpf_insn_cbs cbs = {
		.cb_print	= verbose,
		.private_data	= env,
	};
	struct bpf_insn *insn = env->prog->insnsi + idx;
	u8 class = BPF_CLASS(insn->code);
	u8 opcode = BPF_OP(insn->code);
	u8 mode = BPF_MODE(insn->code);
	u32 dreg = 1u << insn->dst_reg;
	u32 sreg = 1u << insn->src_reg;
	u32 spi;

	if (insn->code == 0)
		return 0;
	if (env->log.level & BPF_LOG_LEVEL) {
		verbose(env, "regs=%x stack=%llx before ", *reg_mask, *stack_mask);
		verbose(env, "%d: ", idx);
		print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
	}

	if (class == BPF_ALU || class == BPF_ALU64) {
		if (!(*reg_mask & dreg))
			return 0;
		if (opcode == BPF_MOV) {
			if (BPF_SRC(insn->code) == BPF_X) {
				/* dreg = sreg
				 * dreg needs precision after this insn
				 * sreg needs precision before this insn
				 */
				*reg_mask &= ~dreg;
				*reg_mask |= sreg;
			} else {
				/* dreg = K
				 * dreg needs precision after this insn.
				 * Corresponding register is already marked
				 * as precise=true in this verifier state.
				 * No further markings in parent are necessary
				 */
				*reg_mask &= ~dreg;
			}
		} else {
			if (BPF_SRC(insn->code) == BPF_X) {
				/* dreg += sreg
				 * both dreg and sreg need precision
				 * before this insn
				 */
				*reg_mask |= sreg;
			} /* else dreg += K
			   * dreg still needs precision before this insn
			   */
		}
	} else if (class == BPF_LDX) {
		if (!(*reg_mask & dreg))
			return 0;
		*reg_mask &= ~dreg;

		/* scalars can only be spilled into stack w/o losing precision.
		 * Load from any other memory can be zero extended.
		 * The desire to keep that precision is already indicated
		 * by 'precise' mark in corresponding register of this state.
		 * No further tracking necessary.
		 */
		if (insn->src_reg != BPF_REG_FP)
			return 0;
		if (BPF_SIZE(insn->code) != BPF_DW)
			return 0;

		/* dreg = *(u64 *)[fp - off] was a fill from the stack.
		 * that [fp - off] slot contains scalar that needs to be
		 * tracked with precision
		 */
		spi = (-insn->off - 1) / BPF_REG_SIZE;
		if (spi >= 64) {
			verbose(env, "BUG spi %d\n", spi);
			WARN_ONCE(1, "verifier backtracking bug");
			return -EFAULT;
		}
		*stack_mask |= 1ull << spi;
	} else if (class == BPF_STX || class == BPF_ST) {
		if (*reg_mask & dreg)
			/* stx & st shouldn't be using _scalar_ dst_reg
			 * to access memory. It means backtracking
			 * encountered a case of pointer subtraction.
			 */
			return -ENOTSUPP;
		/* scalars can only be spilled into stack */
		if (insn->dst_reg != BPF_REG_FP)
			return 0;
		if (BPF_SIZE(insn->code) != BPF_DW)
			return 0;
		spi = (-insn->off - 1) / BPF_REG_SIZE;
		if (spi >= 64) {
			verbose(env, "BUG spi %d\n", spi);
			WARN_ONCE(1, "verifier backtracking bug");
			return -EFAULT;
		}
		if (!(*stack_mask & (1ull << spi)))
			return 0;
		*stack_mask &= ~(1ull << spi);
		if (class == BPF_STX)
			*reg_mask |= sreg;
	} else if (class == BPF_JMP || class == BPF_JMP32) {
		if (opcode == BPF_CALL) {
			if (insn->src_reg == BPF_PSEUDO_CALL)
				return -ENOTSUPP;
			/* regular helper call sets R0 */
			*reg_mask &= ~1;
			if (*reg_mask & 0x3f) {
				/* if backtracing was looking for registers R1-R5
				 * they should have been found already.
				 */
				verbose(env, "BUG regs %x\n", *reg_mask);
				WARN_ONCE(1, "verifier backtracking bug");
				return -EFAULT;
			}
		} else if (opcode == BPF_EXIT) {
			return -ENOTSUPP;
		}
	} else if (class == BPF_LD) {
		if (!(*reg_mask & dreg))
			return 0;
		*reg_mask &= ~dreg;
		/* It's ld_imm64 or ld_abs or ld_ind.
		 * For ld_imm64 no further tracking of precision
		 * into parent is necessary
		 */
		if (mode == BPF_IND || mode == BPF_ABS)
			/* to be analyzed */
			return -ENOTSUPP;
	}
	return 0;
}

Project: linux
File: verifier.c

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

	for (i = 0; i < MAX_BPF_REG; i++) {
		mark_reg_not_init(env, regs, i);
		regs[i].live = REG_LIVE_NONE;
		regs[i].parent = NULL;
		regs[i].subreg_def = DEF_NOT_SUBREG;
	}

	/* frame pointer */
	regs[BPF_REG_FP].type = PTR_TO_STACK;
	mark_reg_known_zero(env, regs, BPF_REG_FP);
	regs[BPF_REG_FP].frameno = state->frameno;
}

Project: linux
File: verifier.c

static int get_prev_insn_idx(struct bpf_verifier_state *st, int i,
			     u32 *history)
{
	u32 cnt = *history;

	if (cnt && st->jmp_history[cnt - 1].idx == i) {
		i = st->jmp_history[cnt - 1].prev_idx;
		(*history)--;
	} else {
		i--;
	}
	return i;
}

Project: linux
File: verifier.c

record_func_map(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_map *map = meta->map_ptr;

	if (func_id != BPF_FUNC_tail_call &&
	    func_id != BPF_FUNC_map_lookup_elem &&
	    func_id != BPF_FUNC_map_update_elem &&
	    func_id != BPF_FUNC_map_delete_elem &&
	    func_id != BPF_FUNC_map_push_elem &&
	    func_id != BPF_FUNC_map_pop_elem &&
	    func_id != BPF_FUNC_map_peek_elem)
		return 0;

	if (map == NULL) {
		verbose(env, "kernel subsystem misconfigured verifier\n");
		return -EINVAL;
	}

	/* In case of read-only, some additional restrictions
	 * need to be applied in order to prevent altering the
	 * state of the map from program side.
	 */
	if ((map->map_flags & BPF_F_RDONLY_PROG) &&
	    (func_id == BPF_FUNC_map_delete_elem ||
	     func_id == BPF_FUNC_map_update_elem ||
	     func_id == BPF_FUNC_map_push_elem ||
	     func_id == BPF_FUNC_map_pop_elem)) {
		verbose(env, "write into map forbidden\n");
		return -EACCES;
	}

	if (!BPF_MAP_PTR(aux->map_ptr_state))
		bpf_map_ptr_store(aux, meta->map_ptr,
				  meta->map_ptr->unpriv_array);
	else if (BPF_MAP_PTR(aux->map_ptr_state) != meta->map_ptr)
		bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON,
				  meta->map_ptr->unpriv_array);
	return 0;
}

Project: linux
File: verifier.c

static int convert_ctx_accesses(struct bpf_verifier_env *env)
{
	const struct bpf_verifier_ops *ops = env->ops;
	int i, cnt, size, ctx_field_size, delta = 0;
	const int insn_cnt = env->prog->len;
	struct bpf_insn insn_buf[16], *insn;
	u32 target_size, size_default, off;
	struct bpf_prog *new_prog;
	enum bpf_access_type type;
	bool is_narrower_load;

	if (ops->gen_prologue || env->seen_direct_write) {
		if (!ops->gen_prologue) {
			verbose(env, "bpf verifier is misconfigured\n");
			return -EINVAL;
		}
		cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
					env->prog);
		if (cnt >= ARRAY_SIZE(insn_buf)) {
			verbose(env, "bpf verifier is misconfigured\n");
			return -EINVAL;
		} else if (cnt) {
			new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt);
			if (!new_prog)
				return -ENOMEM;

			env->prog = new_prog;
			delta += cnt - 1;
		}
	}

	if (bpf_prog_is_dev_bound(env->prog->aux))
		return 0;

	insn = env->prog->insnsi + delta;

	for (i = 0; i < insn_cnt; i++, insn++) {
		bpf_convert_ctx_access_t convert_ctx_access;

		if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
		    insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
		    insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
		    insn->code == (BPF_LDX | BPF_MEM | BPF_DW))
			type = BPF_READ;
		else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) ||
			 insn->code == (BPF_STX | BPF_MEM | BPF_H) ||
			 insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
			 insn->code == (BPF_STX | BPF_MEM | BPF_DW))
			type = BPF_WRITE;
		else
			continue;

		if (type == BPF_WRITE &&
		    env->insn_aux_data[i + delta].sanitize_stack_off) {
			struct bpf_insn patch[] = {
				/* Sanitize suspicious stack slot with zero.
				 * There are no memory dependencies for this store,
				 * since it's only using frame pointer and immediate
				 * constant of zero
				 */
				BPF_ST_MEM(BPF_DW, BPF_REG_FP,
					   env->insn_aux_data[i + delta].sanitize_stack_off,
					   0),
				/* the original STX instruction will immediately
				 * overwrite the same stack slot with appropriate value
				 */
				*insn,
			};

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

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

		switch (env->insn_aux_data[i + delta].ptr_type) {
		case PTR_TO_CTX:
			if (!ops->convert_ctx_access)
				continue;
			convert_ctx_access = ops->convert_ctx_access;
			break;
		case PTR_TO_SOCKET:
		case PTR_TO_SOCK_COMMON:
			convert_ctx_access = bpf_sock_convert_ctx_access;
			break;
		case PTR_TO_TCP_SOCK:
			convert_ctx_access = bpf_tcp_sock_convert_ctx_access;
			break;
		case PTR_TO_XDP_SOCK:
			convert_ctx_access = bpf_xdp_sock_convert_ctx_access;
			break;
		case PTR_TO_BTF_ID:
			if (type == BPF_READ) {
				insn->code = BPF_LDX | BPF_PROBE_MEM |
					BPF_SIZE((insn)->code);
				env->prog->aux->num_exentries++;
			} else if (env->prog->type != BPF_PROG_TYPE_STRUCT_OPS) {
				verbose(env, "Writes through BTF pointers are not allowed\n");
				return -EINVAL;
			}
			continue;
		default:
			continue;
		}

		ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size;
		size = BPF_LDST_BYTES(insn);

		/* If the read access is a narrower load of the field,
		 * convert to a 4/8-byte load, to minimum program type specific
		 * convert_ctx_access changes. If conversion is successful,
		 * we will apply proper mask to the result.
		 */
		is_narrower_load = size < ctx_field_size;
		size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
		off = insn->off;
		if (is_narrower_load) {
			u8 size_code;

			if (type == BPF_WRITE) {
				verbose(env, "bpf verifier narrow ctx access misconfigured\n");
				return -EINVAL;
			}

			size_code = BPF_H;
			if (ctx_field_size == 4)
				size_code = BPF_W;
			else if (ctx_field_size == 8)
				size_code = BPF_DW;

			insn->off = off & ~(size_default - 1);
			insn->code = BPF_LDX | BPF_MEM | size_code;
		}

		target_size = 0;
		cnt = convert_ctx_access(type, insn, insn_buf, env->prog,
					 &target_size);
		if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) ||
		    (ctx_field_size && !target_size)) {
			verbose(env, "bpf verifier is misconfigured\n");
			return -EINVAL;
		}

		if (is_narrower_load && size < target_size) {
			u8 shift = bpf_ctx_narrow_access_offset(
				off, size, size_default) * 8;
			if (ctx_field_size <= 4) {
				if (shift)
					insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH,
									insn->dst_reg,
									shift);
				insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
								(1 << size * 8) - 1);
			} else {
				if (shift)
					insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH,
									insn->dst_reg,
									shift);
				insn_buf[cnt++] = BPF_ALU64_IMM(BPF_AND, insn->dst_reg,
								(1ULL << size * 8) - 1);
			}
		}

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

		delta += cnt - 1;

		/* keep walking new program and skip insns we just inserted */
		env->prog = new_prog;
		insn      = new_prog->insnsi + i + delta;
	}

	return 0;
}

Project: linux
File: verifier.c

static bool is_acquire_function(enum bpf_func_id func_id)
{
	return func_id == BPF_FUNC_sk_lookup_tcp ||
		func_id == BPF_FUNC_sk_lookup_udp ||
		func_id == BPF_FUNC_skc_lookup_tcp;
}

Project: linux
File: verifier.c

static bool is_tracing_prog_type(enum bpf_prog_type type)
{
	switch (type) {
	case BPF_PROG_TYPE_KPROBE:
	case BPF_PROG_TYPE_TRACEPOINT:
	case BPF_PROG_TYPE_PERF_EVENT:
	case BPF_PROG_TYPE_RAW_TRACEPOINT:
		return true;
	default:
		return false;
	}
}

Project: linux
File: verifier.c

static int check_cond_jmp_op(struct bpf_verifier_env *env,
			     struct bpf_insn *insn, int *insn_idx)
{
	struct bpf_verifier_state *this_branch = env->cur_state;
	struct bpf_verifier_state *other_branch;
	struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs;
	struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL;
	u8 opcode = BPF_OP(insn->code);
	bool is_jmp32;
	int pred = -1;
	int err;

	/* Only conditional jumps are expected to reach here. */
	if (opcode == BPF_JA || opcode > BPF_JSLE) {
		verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode);
		return -EINVAL;
	}

	if (BPF_SRC(insn->code) == BPF_X) {
		if (insn->imm != 0) {
			verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
			return -EINVAL;
		}

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

		if (is_pointer_value(env, insn->src_reg)) {
			verbose(env, "R%d pointer comparison prohibited\n",
				insn->src_reg);
			return -EACCES;
		}
		src_reg = &regs[insn->src_reg];
	} else {
		if (insn->src_reg != BPF_REG_0) {
			verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
			return -EINVAL;
		}
	}

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

	dst_reg = &regs[insn->dst_reg];
	is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;

	if (BPF_SRC(insn->code) == BPF_K)
		pred = is_branch_taken(dst_reg, insn->imm,
				       opcode, is_jmp32);
	else if (src_reg->type == SCALAR_VALUE &&
		 tnum_is_const(src_reg->var_off))
		pred = is_branch_taken(dst_reg, src_reg->var_off.value,
				       opcode, is_jmp32);
	if (pred >= 0) {
		err = mark_chain_precision(env, insn->dst_reg);
		if (BPF_SRC(insn->code) == BPF_X && !err)
			err = mark_chain_precision(env, insn->src_reg);
		if (err)
			return err;
	}
	if (pred == 1) {
		/* only follow the goto, ignore fall-through */
		*insn_idx += insn->off;
		return 0;
	} else if (pred == 0) {
		/* only follow fall-through branch, since
		 * that's where the program will go
		 */
		return 0;
	}

	other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx,
				  false);
	if (!other_branch)
		return -EFAULT;
	other_branch_regs = other_branch->frame[other_branch->curframe]->regs;

	/* detect if we are comparing against a constant value so we can adjust
	 * our min/max values for our dst register.
	 * this is only legit if both are scalars (or pointers to the same
	 * object, I suppose, but we don't support that right now), because
	 * otherwise the different base pointers mean the offsets aren't
	 * comparable.
	 */
	if (BPF_SRC(insn->code) == BPF_X) {
		struct bpf_reg_state *src_reg = &regs[insn->src_reg];
		struct bpf_reg_state lo_reg0 = *dst_reg;
		struct bpf_reg_state lo_reg1 = *src_reg;
		struct bpf_reg_state *src_lo, *dst_lo;

		dst_lo = &lo_reg0;
		src_lo = &lo_reg1;
		coerce_reg_to_size(dst_lo, 4);
		coerce_reg_to_size(src_lo, 4);

		if (dst_reg->type == SCALAR_VALUE &&
		    src_reg->type == SCALAR_VALUE) {
			if (tnum_is_const(src_reg->var_off) ||
			    (is_jmp32 && tnum_is_const(src_lo->var_off)))
				reg_set_min_max(&other_branch_regs[insn->dst_reg],
						dst_reg,
						is_jmp32
						? src_lo->var_off.value
						: src_reg->var_off.value,
						opcode, is_jmp32);
			else if (tnum_is_const(dst_reg->var_off) ||
				 (is_jmp32 && tnum_is_const(dst_lo->var_off)))
				reg_set_min_max_inv(&other_branch_regs[insn->src_reg],
						    src_reg,
						    is_jmp32
						    ? dst_lo->var_off.value
						    : dst_reg->var_off.value,
						    opcode, is_jmp32);
			else if (!is_jmp32 &&
				 (opcode == BPF_JEQ || opcode == BPF_JNE))
				/* Comparing for equality, we can combine knowledge */
				reg_combine_min_max(&other_branch_regs[insn->src_reg],
						    &other_branch_regs[insn->dst_reg],
						    src_reg, dst_reg, opcode);
		}
	} else if (dst_reg->type == SCALAR_VALUE) {
		reg_set_min_max(&other_branch_regs[insn->dst_reg],
					dst_reg, insn->imm, opcode, is_jmp32);
	}

	/* detect if R == 0 where R is returned from bpf_map_lookup_elem().
	 * NOTE: these optimizations below are related with pointer comparison
	 *       which will never be JMP32.
	 */
	if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K &&
	    insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) &&
	    reg_type_may_be_null(dst_reg->type)) {
		/* Mark all identical registers in each branch as either
		 * safe or unknown depending R == 0 or R != 0 conditional.
		 */
		mark_ptr_or_null_regs(this_branch, insn->dst_reg,
				      opcode == BPF_JNE);
		mark_ptr_or_null_regs(other_branch, insn->dst_reg,
				      opcode == BPF_JEQ);
	} else if (!try_match_pkt_pointers(insn, dst_reg, &regs[insn->src_reg],
					   this_branch, other_branch) &&
		   is_pointer_value(env, insn->dst_reg)) {
		verbose(env, "R%d pointer comparison prohibited\n",
			insn->dst_reg);
		return -EACCES;
	}
	if (env->log.level & BPF_LOG_LEVEL)
		print_verifier_state(env, this_branch->frame[this_branch->curframe]);
	return 0;
}

Project: linux
File: verifier.c

static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env,
					     int insn_idx, int prev_insn_idx,
					     bool speculative)
{
	struct bpf_verifier_state *cur = env->cur_state;
	struct bpf_verifier_stack_elem *elem;
	int err;

	elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
	if (!elem)
		goto err;

	elem->insn_idx = insn_idx;
	elem->prev_insn_idx = prev_insn_idx;
	elem->next = env->head;
	env->head = elem;
	env->stack_size++;
	err = copy_verifier_state(&elem->st, cur);
	if (err)
		goto err;
	elem->st.speculative |= speculative;
	if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
		verbose(env, "The sequence of %d jumps is too complex.\n",
			env->stack_size);
		goto err;
	}
	if (elem->st.parent) {
		++elem->st.parent->branches;
		/* WARN_ON(branches > 2) technically makes sense here,
		 * but
		 * 1. speculative states will bump 'branches' for non-branch
		 * instructions
		 * 2. is_state_visited() heuristics may decide not to create
		 * a new state for a sequence of branches and all such current
		 * and cloned states will be pointing to a single parent state
		 * which might have large 'branches' count.
		 */
	}
	return &elem->st;
err:
	free_verifier_state(env->cur_state, true);
	env->cur_state = NULL;
	/* pop all elements and return */
	while (!pop_stack(env, NULL, NULL));
	return NULL;
}

Project: linux
File: verifier.c

static bool check_refcount_ok(const struct bpf_func_proto *fn, int func_id)
{
	int count = 0;

	if (arg_type_may_be_refcounted(fn->arg1_type))
		count++;
	if (arg_type_may_be_refcounted(fn->arg2_type))
		count++;
	if (arg_type_may_be_refcounted(fn->arg3_type))
		count++;
	if (arg_type_may_be_refcounted(fn->arg4_type))
		count++;
	if (arg_type_may_be_refcounted(fn->arg5_type))
		count++;

	/* A reference acquiring function cannot acquire
	 * another refcounted ptr.
	 */
	if (is_acquire_function(func_id) && count)
		return false;

	/* We only support one arg being unreferenced at the moment,
	 * which is sufficient for the helper functions we have right now.
	 */
	return count <= 1;
}

Project: linux
File: verifier.c

static bool is_preallocated_map(struct bpf_map *map)
{
	if (!check_map_prealloc(map))
		return false;
	if (map->inner_map_meta && !check_map_prealloc(map->inner_map_meta))
		return false;
	return true;
}

Project: linux
File: verifier.c

static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off,
				      u32 cnt)
{
	struct bpf_prog *prog = env->prog;
	u32 i, l_off, l_cnt, nr_linfo;
	struct bpf_line_info *linfo;

	nr_linfo = prog->aux->nr_linfo;
	if (!nr_linfo)
		return 0;

	linfo = prog->aux->linfo;

	/* find first line info to remove, count lines to be removed */
	for (i = 0; i < nr_linfo; i++)
		if (linfo[i].insn_off >= off)
			break;

	l_off = i;
	l_cnt = 0;
	for (; i < nr_linfo; i++)
		if (linfo[i].insn_off < off + cnt)
			l_cnt++;
		else
			break;

	/* First live insn doesn't match first live linfo, it needs to "inherit"
	 * last removed linfo.  prog is already modified, so prog->len == off
	 * means no live instructions after (tail of the program was removed).
	 */
	if (prog->len != off && l_cnt &&
	    (i == nr_linfo || linfo[i].insn_off != off + cnt)) {
		l_cnt--;
		linfo[--i].insn_off = off + cnt;
	}

	/* remove the line info which refer to the removed instructions */
	if (l_cnt) {
		memmove(linfo + l_off, linfo + i,
			sizeof(*linfo) * (nr_linfo - i));

		prog->aux->nr_linfo -= l_cnt;
		nr_linfo = prog->aux->nr_linfo;
	}

	/* pull all linfo[i].insn_off >= off + cnt in by cnt */
	for (i = l_off; i < nr_linfo; i++)
		linfo[i].insn_off -= cnt;

	/* fix up all subprogs (incl. 'exit') which start >= off */
	for (i = 0; i <= env->subprog_cnt; i++)
		if (env->subprog_info[i].linfo_idx > l_off) {
			/* program may have started in the removed region but
			 * may not be fully removed
			 */
			if (env->subprog_info[i].linfo_idx >= l_off + l_cnt)
				env->subprog_info[i].linfo_idx -= l_cnt;
			else
				env->subprog_info[i].linfo_idx = l_off;
		}

	return 0;
}

Project: linux
File: verifier.c

static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
				      struct bpf_insn *insn,
				      struct bpf_reg_state *dst_reg,
				      struct bpf_reg_state src_reg)
{
	struct bpf_reg_state *regs = cur_regs(env);
	u8 opcode = BPF_OP(insn->code);
	bool src_known, dst_known;
	s64 smin_val, smax_val;
	u64 umin_val, umax_val;
	u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
	u32 dst = insn->dst_reg;
	int ret;

	if (insn_bitness == 32) {
		/* Relevant for 32-bit RSH: Information can propagate towards
		 * LSB, so it isn't sufficient to only truncate the output to
		 * 32 bits.
		 */
		coerce_reg_to_size(dst_reg, 4);
		coerce_reg_to_size(&src_reg, 4);
	}

	smin_val = src_reg.smin_value;
	smax_val = src_reg.smax_value;
	umin_val = src_reg.umin_value;
	umax_val = src_reg.umax_value;
	src_known = tnum_is_const(src_reg.var_off);
	dst_known = tnum_is_const(dst_reg->var_off);

	if ((src_known && (smin_val != smax_val || umin_val != umax_val)) ||
	    smin_val > smax_val || umin_val > umax_val) {
		/* Taint dst register if offset had invalid bounds derived from
		 * e.g. dead branches.
		 */
		__mark_reg_unknown(env, dst_reg);
		return 0;
	}

	if (!src_known &&
	    opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) {
		__mark_reg_unknown(env, dst_reg);
		return 0;
	}

	switch (opcode) {
	case BPF_ADD:
		ret = sanitize_val_alu(env, insn);
		if (ret < 0) {
			verbose(env, "R%d tried to add from different pointers or scalars\n", dst);
			return ret;
		}
		scalar_min_max_add(dst_reg, &src_reg);
		break;
	case BPF_SUB:
		ret = sanitize_val_alu(env, insn);
		if (ret < 0) {
			verbose(env, "R%d tried to sub from different pointers or scalars\n", dst);
			return ret;
		}
		scalar_min_max_sub(dst_reg, &src_reg);
		break;
	case BPF_MUL:
		scalar_min_max_mul(dst_reg, &src_reg);
		break;
	case BPF_AND:
		if (src_known && dst_known) {
			__mark_reg_known(dst_reg, dst_reg->var_off.value &
						  src_reg.var_off.value);
			break;
		}
		scalar_min_max_and(dst_reg, &src_reg);
		break;
	case BPF_OR:
		if (src_known && dst_known) {
			__mark_reg_known(dst_reg, dst_reg->var_off.value |
						  src_reg.var_off.value);
			break;
		}
		scalar_min_max_or(dst_reg, &src_reg);
		break;
	case BPF_LSH:
		if (umax_val >= insn_bitness) {
			/* Shifts greater than 31 or 63 are undefined.
			 * This includes shifts by a negative number.
			 */
			mark_reg_unknown(env, regs, insn->dst_reg);
			break;
		}
		scalar_min_max_lsh(dst_reg, &src_reg);
		break;
	case BPF_RSH:
		if (umax_val >= insn_bitness) {
			/* Shifts greater than 31 or 63 are undefined.
			 * This includes shifts by a negative number.
			 */
			mark_reg_unknown(env, regs, insn->dst_reg);
			break;
		}
		scalar_min_max_rsh(dst_reg, &src_reg);
		break;
	case BPF_ARSH:
		if (umax_val >= insn_bitness) {
			/* Shifts greater than 31 or 63 are undefined.
			 * This includes shifts by a negative number.
			 */
			mark_reg_unknown(env, regs, insn->dst_reg);
			break;
		}
		scalar_min_max_arsh(dst_reg, &src_reg, insn_bitness);
		break;
	default:
		mark_reg_unknown(env, regs, insn->dst_reg);
		break;
	}

	if (BPF_CLASS(insn->code) != BPF_ALU64) {
		/* 32-bit ALU ops are (32,32)->32 */
		coerce_reg_to_size(dst_reg, 4);
	}

	__update_reg_bounds(dst_reg);
	__reg_deduce_bounds(dst_reg);
	__reg_bound_offset(dst_reg);
	return 0;
}

Project: linux
File: verifier.c

static void save_register_state(struct bpf_func_state *state,
				int spi, struct bpf_reg_state *reg)
{
	int i;

	state->stack[spi].spilled_ptr = *reg;
	state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;

	for (i = 0; i < BPF_REG_SIZE; i++)
		state->stack[spi].slot_type[i] = STACK_SPILL;
}

Project: linux
File: verifier.c

static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx,
		     int *insn_idx)
{
	struct bpf_verifier_state *cur = env->cur_state;
	struct bpf_verifier_stack_elem *elem, *head = env->head;
	int err;

	if (env->head == NULL)
		return -ENOENT;

	if (cur) {
		err = copy_verifier_state(cur, &head->st);
		if (err)
			return err;
	}
	if (insn_idx)
		*insn_idx = head->insn_idx;
	if (prev_insn_idx)
		*prev_insn_idx = head->prev_insn_idx;
	elem = head->next;
	free_verifier_state(&head->st, false);
	kfree(head);
	env->head = elem;
	env->stack_size--;
	return 0;
}

Project: linux
File: verifier.c

find_linfo(const struct bpf_verifier_env *env, u32 insn_off)
{
	const struct bpf_line_info *linfo;
	const struct bpf_prog *prog;
	u32 i, nr_linfo;

	prog = env->prog;
	nr_linfo = prog->aux->nr_linfo;

	if (!nr_linfo || insn_off >= prog->len)
		return NULL;

	linfo = prog->aux->linfo;
	for (i = 1; i < nr_linfo; i++)
		if (insn_off < linfo[i].insn_off)
			break;

	return &linfo[i - 1];
}

Project: linux
File: verifier.c

static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur,
		    struct idpair *idmap)
{
	bool equal;

	if (!(rold->live & REG_LIVE_READ))
		/* explored state didn't use this */
		return true;

	equal = memcmp(rold, rcur, offsetof(struct bpf_reg_state, parent)) == 0;

	if (rold->type == PTR_TO_STACK)
		/* two stack pointers are equal only if they're pointing to
		 * the same stack frame, since fp-8 in foo != fp-8 in bar
		 */
		return equal && rold->frameno == rcur->frameno;

	if (equal)
		return true;

	if (rold->type == NOT_INIT)
		/* explored state can't have used this */
		return true;
	if (rcur->type == NOT_INIT)
		return false;
	switch (rold->type) {
	case SCALAR_VALUE:
		if (rcur->type == SCALAR_VALUE) {
			if (!rold->precise && !rcur->precise)
				return true;
			/* new val must satisfy old val knowledge */
			return range_within(rold, rcur) &&
			       tnum_in(rold->var_off, rcur->var_off);
		} else {
			/* We're trying to use a pointer in place of a scalar.
			 * Even if the scalar was unbounded, this could lead to
			 * pointer leaks because scalars are allowed to leak
			 * while pointers are not. We could make this safe in
			 * special cases if root is calling us, but it's
			 * probably not worth the hassle.
			 */
			return false;
		}
	case PTR_TO_MAP_VALUE:
		/* If the new min/max/var_off satisfy the old ones and
		 * everything else matches, we are OK.
		 * 'id' is not compared, since it's only used for maps with
		 * bpf_spin_lock inside map element and in such cases if
		 * the rest of the prog is valid for one map element then
		 * it's valid for all map elements regardless of the key
		 * used in bpf_map_lookup()
		 */
		return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
		       range_within(rold, rcur) &&
		       tnum_in(rold->var_off, rcur->var_off);
	case PTR_TO_MAP_VALUE_OR_NULL:
		/* a PTR_TO_MAP_VALUE could be safe to use as a
		 * PTR_TO_MAP_VALUE_OR_NULL into the same map.
		 * However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL-
		 * checked, doing so could have affected others with the same
		 * id, and we can't check for that because we lost the id when
		 * we converted to a PTR_TO_MAP_VALUE.
		 */
		if (rcur->type != PTR_TO_MAP_VALUE_OR_NULL)
			return false;
		if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)))
			return false;
		/* Check our ids match any regs they're supposed to */
		return check_ids(rold->id, rcur->id, idmap);
	case PTR_TO_PACKET_META:
	case PTR_TO_PACKET:
		if (rcur->type != rold->type)
			return false;
		/* We must have at least as much range as the old ptr
		 * did, so that any accesses which were safe before are
		 * still safe.  This is true even if old range < old off,
		 * since someone could have accessed through (ptr - k), or
		 * even done ptr -= k in a register, to get a safe access.
		 */
		if (rold->range > rcur->range)
			return false;
		/* If the offsets don't match, we can't trust our alignment;
		 * nor can we be sure that we won't fall out of range.
		 */
		if (rold->off != rcur->off)
			return false;
		/* id relations must be preserved */
		if (rold->id && !check_ids(rold->id, rcur->id, idmap))
			return false;
		/* new val must satisfy old val knowledge */
		return range_within(rold, rcur) &&
		       tnum_in(rold->var_off, rcur->var_off);
	case PTR_TO_CTX:
	case CONST_PTR_TO_MAP:
	case PTR_TO_PACKET_END:
	case PTR_TO_FLOW_KEYS:
	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:
		/* Only valid matches are exact, which memcmp() above
		 * would have accepted
		 */
	default:
		/* Don't know what's going on, just say it's not safe */
		return false;
	}

	/* Shouldn't get here; if we do, say it's not safe */
	WARN_ON_ONCE(1);
	return false;
}

Project: linux
File: verifier.c

static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env,
					 const union bpf_attr *attr)
{
	struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4];
	struct bpf_insn_aux_data *aux = env->insn_aux_data;
	int i, patch_len, delta = 0, len = env->prog->len;
	struct bpf_insn *insns = env->prog->insnsi;
	struct bpf_prog *new_prog;
	bool rnd_hi32;

	rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32;
	zext_patch[1] = BPF_ZEXT_REG(0);
	rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0);
	rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
	rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX);
	for (i = 0; i < len; i++) {
		int adj_idx = i + delta;
		struct bpf_insn insn;

		insn = insns[adj_idx];
		if (!aux[adj_idx].zext_dst) {
			u8 code, class;
			u32 imm_rnd;

			if (!rnd_hi32)
				continue;

			code = insn.code;
			class = BPF_CLASS(code);
			if (insn_no_def(&insn))
				continue;

			/* NOTE: arg "reg" (the fourth one) is only used for
			 *       BPF_STX which has been ruled out in above
			 *       check, it is safe to pass NULL here.
			 */
			if (is_reg64(env, &insn, insn.dst_reg, NULL, DST_OP)) {
				if (class == BPF_LD &&
				    BPF_MODE(code) == BPF_IMM)
					i++;
				continue;
			}

			/* ctx load could be transformed into wider load. */
			if (class == BPF_LDX &&
			    aux[adj_idx].ptr_type == PTR_TO_CTX)
				continue;

			imm_rnd = get_random_int();
			rnd_hi32_patch[0] = insn;
			rnd_hi32_patch[1].imm = imm_rnd;
			rnd_hi32_patch[3].dst_reg = insn.dst_reg;
			patch = rnd_hi32_patch;
			patch_len = 4;
			goto apply_patch_buffer;
		}

		if (!bpf_jit_needs_zext())
			continue;

		zext_patch[0] = insn;
		zext_patch[1].dst_reg = insn.dst_reg;
		zext_patch[1].src_reg = insn.dst_reg;
		patch = zext_patch;
		patch_len = 2;
apply_patch_buffer:
		new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len);
		if (!new_prog)
			return -ENOMEM;
		env->prog = new_prog;
		insns = new_prog->insnsi;
		aux = env->insn_aux_data;
		delta += patch_len - 1;
	}

	return 0;
}

Project: linux
File: verifier.c

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