Commit message: binfmt_elf: use ELF_ET_DYN_BASE only for PIE

The ELF_ET_DYN_BASE position was originally intended to keep loaders
away from ET_EXEC binaries.  (For example, running "/lib/ld-linux.so.2
/bin/cat" might cause the subsequent load of /bin/cat into where the
loader had been loaded.)

With the advent of PIE (ET_DYN binaries with an INTERP Program Header),
ELF_ET_DYN_BASE continued to be used since the kernel was only looking
at ET_DYN.  However, since ELF_ET_DYN_BASE is traditionally set at the
top 1/3rd of the TASK_SIZE, a substantial portion of the address space
is unused.

For 32-bit tasks when RLIMIT_STACK is set to RLIM_INFINITY, programs are
loaded above the mmap region.  This means they can be made to collide
(CVE-2017-1000370) or nearly collide (CVE-2017-1000371) with
pathological stack regions.

Lowering ELF_ET_DYN_BASE solves both by moving programs below the mmap
region in all cases, and will now additionally avoid programs falling
back to the mmap region by enforcing MAP_FIXED for program loads (i.e.
if it would have collided with the stack, now it will fail to load
instead of falling back to the mmap region).

To allow for a lower ELF_ET_DYN_BASE, loaders (ET_DYN without INTERP)
are loaded into the mmap region, leaving space available for either an
ET_EXEC binary with a fixed location or PIE being loaded into mmap by
the loader.  Only PIE programs are loaded offset from ELF_ET_DYN_BASE,
which means architectures can now safely lower their values without risk
of loaders colliding with their subsequently loaded programs.

For 64-bit, ELF_ET_DYN_BASE is best set to 4GB to allow runtimes to use
the entire 32-bit address space for 32-bit pointers.

Thanks to PaX Team, Daniel Micay, and Rik van Riel for inspiration and
suggestions on how to implement this solution.

Fixes: d1fd836dcf00 ("mm: split ET_DYN ASLR from mmap ASLR")
Link: http://lkml.kernel.org/r/20170621173201.GA114489@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Qualys Security Advisory <qsa@qualys.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CVE: CVE-2017-1000371
CWE: NVD-CWE-noinfo
Vulnerability description: The offset2lib patch as used by the Linux Kernel contains a vulnerability, if RLIMIT_STACK is set to RLIM_INFINITY and 1 Gigabyte of memory is allocated (the maximum under the 1/4 restriction) then the stack will be grown down to 0x80000000, and as the PIE binary is mapped above 0x80000000 the minimum distance between the end of the PIE binary's read-write segment and the start of the stack becomes small enough that the stack guard page can be jumped over by an attacker. This affects Linux Kernel version 4.11.5. This is a different issue than CVE-2017-1000370 and CVE-2017-1000365. This issue appears to be limited to i386 based systems.

Project: linux
File: binfmt_elf.c

static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
		struct file *interpreter, unsigned long *interp_map_addr,
		unsigned long no_base, struct elf_phdr *interp_elf_phdata)
{
	struct elf_phdr *eppnt;
	unsigned long load_addr = 0;
	int load_addr_set = 0;
	unsigned long last_bss = 0, elf_bss = 0;
	int bss_prot = 0;
	unsigned long error = ~0UL;
	unsigned long total_size;
	int i;

	/* First of all, some simple consistency checks */
	if (interp_elf_ex->e_type != ET_EXEC &&
	    interp_elf_ex->e_type != ET_DYN)
		goto out;
	if (!elf_check_arch(interp_elf_ex))
		goto out;
	if (!interpreter->f_op->mmap)
		goto out;

	total_size = total_mapping_size(interp_elf_phdata,
					interp_elf_ex->e_phnum);
	if (!total_size) {
		error = -EINVAL;
		goto out;
	}

	eppnt = interp_elf_phdata;
	for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
		if (eppnt->p_type == PT_LOAD) {
			int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
			int elf_prot = 0;
			unsigned long vaddr = 0;
			unsigned long k, map_addr;

			if (eppnt->p_flags & PF_R)
		    		elf_prot = PROT_READ;
			if (eppnt->p_flags & PF_W)
				elf_prot |= PROT_WRITE;
			if (eppnt->p_flags & PF_X)
				elf_prot |= PROT_EXEC;
			vaddr = eppnt->p_vaddr;
			if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
				elf_type |= MAP_FIXED;
			else if (no_base && interp_elf_ex->e_type == ET_DYN)
				load_addr = -vaddr;

			map_addr = elf_map(interpreter, load_addr + vaddr,
					eppnt, elf_prot, elf_type, total_size);
			total_size = 0;
			if (!*interp_map_addr)
				*interp_map_addr = map_addr;
			error = map_addr;
			if (BAD_ADDR(map_addr))
				goto out;

			if (!load_addr_set &&
			    interp_elf_ex->e_type == ET_DYN) {
				load_addr = map_addr - ELF_PAGESTART(vaddr);
				load_addr_set = 1;
			}

			/*
			 * Check to see if the section's size will overflow the
			 * allowed task size. Note that p_filesz must always be
			 * <= p_memsize so it's only necessary to check p_memsz.
			 */
			k = load_addr + eppnt->p_vaddr;
			if (BAD_ADDR(k) ||
			    eppnt->p_filesz > eppnt->p_memsz ||
			    eppnt->p_memsz > TASK_SIZE ||
			    TASK_SIZE - eppnt->p_memsz < k) {
				error = -ENOMEM;
				goto out;
			}

			/*
			 * Find the end of the file mapping for this phdr, and
			 * keep track of the largest address we see for this.
			 */
			k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
			if (k > elf_bss)
				elf_bss = k;

			/*
			 * Do the same thing for the memory mapping - between
			 * elf_bss and last_bss is the bss section.
			 */
			k = load_addr + eppnt->p_vaddr + eppnt->p_memsz;
			if (k > last_bss) {
				last_bss = k;
				bss_prot = elf_prot;
			}
		}
	}

	/*
	 * Now fill out the bss section: first pad the last page from
	 * the file up to the page boundary, and zero it from elf_bss
	 * up to the end of the page.
	 */
	if (padzero(elf_bss)) {
		error = -EFAULT;
		goto out;
	}
	/*
	 * Next, align both the file and mem bss up to the page size,
	 * since this is where elf_bss was just zeroed up to, and where
	 * last_bss will end after the vm_brk_flags() below.
	 */
	elf_bss = ELF_PAGEALIGN(elf_bss);
	last_bss = ELF_PAGEALIGN(last_bss);
	/* Finally, if there is still more bss to allocate, do it. */
	if (last_bss > elf_bss) {
		error = vm_brk_flags(elf_bss, last_bss - elf_bss,
				bss_prot & PROT_EXEC ? VM_EXEC : 0);
		if (error)
			goto out;
	}

	error = load_addr;
out:
	return error;
}

Project: linux
File: binfmt_elf.c

static int load_elf_binary(struct linux_binprm *bprm)
{
	struct file *interpreter = NULL; /* to shut gcc up */
 	unsigned long load_addr = 0, load_bias = 0;
	int load_addr_set = 0;
	char * elf_interpreter = NULL;
	unsigned long error;
	struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
	unsigned long elf_bss, elf_brk;
	int bss_prot = 0;
	int retval, i;
	unsigned long elf_entry;
	unsigned long interp_load_addr = 0;
	unsigned long start_code, end_code, start_data, end_data;
	unsigned long reloc_func_desc __maybe_unused = 0;
	int executable_stack = EXSTACK_DEFAULT;
	struct pt_regs *regs = current_pt_regs();
	struct {
		struct elfhdr elf_ex;
		struct elfhdr interp_elf_ex;
	} *loc;
	struct arch_elf_state arch_state = INIT_ARCH_ELF_STATE;

	loc = kmalloc(sizeof(*loc), GFP_KERNEL);
	if (!loc) {
		retval = -ENOMEM;
		goto out_ret;
	}
	
	/* Get the exec-header */
	loc->elf_ex = *((struct elfhdr *)bprm->buf);

	retval = -ENOEXEC;
	/* First of all, some simple consistency checks */
	if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
		goto out;

	if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
		goto out;
	if (!elf_check_arch(&loc->elf_ex))
		goto out;
	if (!bprm->file->f_op->mmap)
		goto out;

	elf_phdata = load_elf_phdrs(&loc->elf_ex, bprm->file);
	if (!elf_phdata)
		goto out;

	elf_ppnt = elf_phdata;
	elf_bss = 0;
	elf_brk = 0;

	start_code = ~0UL;
	end_code = 0;
	start_data = 0;
	end_data = 0;

	for (i = 0; i < loc->elf_ex.e_phnum; i++) {
		if (elf_ppnt->p_type == PT_INTERP) {
			/* This is the program interpreter used for
			 * shared libraries - for now assume that this
			 * is an a.out format binary
			 */
			retval = -ENOEXEC;
			if (elf_ppnt->p_filesz > PATH_MAX || 
			    elf_ppnt->p_filesz < 2)
				goto out_free_ph;

			retval = -ENOMEM;
			elf_interpreter = kmalloc(elf_ppnt->p_filesz,
						  GFP_KERNEL);
			if (!elf_interpreter)
				goto out_free_ph;

			retval = kernel_read(bprm->file, elf_ppnt->p_offset,
					     elf_interpreter,
					     elf_ppnt->p_filesz);
			if (retval != elf_ppnt->p_filesz) {
				if (retval >= 0)
					retval = -EIO;
				goto out_free_interp;
			}
			/* make sure path is NULL terminated */
			retval = -ENOEXEC;
			if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
				goto out_free_interp;

			interpreter = open_exec(elf_interpreter);
			retval = PTR_ERR(interpreter);
			if (IS_ERR(interpreter))
				goto out_free_interp;

			/*
			 * If the binary is not readable then enforce
			 * mm->dumpable = 0 regardless of the interpreter's
			 * permissions.
			 */
			would_dump(bprm, interpreter);

			/* Get the exec headers */
			retval = kernel_read(interpreter, 0,
					     (void *)&loc->interp_elf_ex,
					     sizeof(loc->interp_elf_ex));
			if (retval != sizeof(loc->interp_elf_ex)) {
				if (retval >= 0)
					retval = -EIO;
				goto out_free_dentry;
			}

			break;
		}
		elf_ppnt++;
	}

	elf_ppnt = elf_phdata;
	for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
		switch (elf_ppnt->p_type) {
		case PT_GNU_STACK:
			if (elf_ppnt->p_flags & PF_X)
				executable_stack = EXSTACK_ENABLE_X;
			else
				executable_stack = EXSTACK_DISABLE_X;
			break;

		case PT_LOPROC ... PT_HIPROC:
			retval = arch_elf_pt_proc(&loc->elf_ex, elf_ppnt,
						  bprm->file, false,
						  &arch_state);
			if (retval)
				goto out_free_dentry;
			break;
		}

	/* Some simple consistency checks for the interpreter */
	if (elf_interpreter) {
		retval = -ELIBBAD;
		/* Not an ELF interpreter */
		if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
			goto out_free_dentry;
		/* Verify the interpreter has a valid arch */
		if (!elf_check_arch(&loc->interp_elf_ex))
			goto out_free_dentry;

		/* Load the interpreter program headers */
		interp_elf_phdata = load_elf_phdrs(&loc->interp_elf_ex,
						   interpreter);
		if (!interp_elf_phdata)
			goto out_free_dentry;

		/* Pass PT_LOPROC..PT_HIPROC headers to arch code */
		elf_ppnt = interp_elf_phdata;
		for (i = 0; i < loc->interp_elf_ex.e_phnum; i++, elf_ppnt++)
			switch (elf_ppnt->p_type) {
			case PT_LOPROC ... PT_HIPROC:
				retval = arch_elf_pt_proc(&loc->interp_elf_ex,
							  elf_ppnt, interpreter,
							  true, &arch_state);
				if (retval)
					goto out_free_dentry;
				break;
			}
	}

	/*
	 * Allow arch code to reject the ELF at this point, whilst it's
	 * still possible to return an error to the code that invoked
	 * the exec syscall.
	 */
	retval = arch_check_elf(&loc->elf_ex,
				!!interpreter, &loc->interp_elf_ex,
				&arch_state);
	if (retval)
		goto out_free_dentry;

	/* Flush all traces of the currently running executable */
	retval = flush_old_exec(bprm);
	if (retval)
		goto out_free_dentry;

	/* Do this immediately, since STACK_TOP as used in setup_arg_pages
	   may depend on the personality.  */
	SET_PERSONALITY2(loc->elf_ex, &arch_state);
	if (elf_read_implies_exec(loc->elf_ex, executable_stack))
		current->personality |= READ_IMPLIES_EXEC;

	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
		current->flags |= PF_RANDOMIZE;

	setup_new_exec(bprm);
	install_exec_creds(bprm);

	/* Do this so that we can load the interpreter, if need be.  We will
	   change some of these later */
	retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
				 executable_stack);
	if (retval < 0)
		goto out_free_dentry;
	
	current->mm->start_stack = bprm->p;

	/* Now we do a little grungy work by mmapping the ELF image into
	   the correct location in memory. */
	for(i = 0, elf_ppnt = elf_phdata;
	    i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
		int elf_prot = 0, elf_flags;
		unsigned long k, vaddr;
		unsigned long total_size = 0;

		if (elf_ppnt->p_type != PT_LOAD)
			continue;

		if (unlikely (elf_brk > elf_bss)) {
			unsigned long nbyte;
	            
			/* There was a PT_LOAD segment with p_memsz > p_filesz
			   before this one. Map anonymous pages, if needed,
			   and clear the area.  */
			retval = set_brk(elf_bss + load_bias,
					 elf_brk + load_bias,
					 bss_prot);
			if (retval)
				goto out_free_dentry;
			nbyte = ELF_PAGEOFFSET(elf_bss);
			if (nbyte) {
				nbyte = ELF_MIN_ALIGN - nbyte;
				if (nbyte > elf_brk - elf_bss)
					nbyte = elf_brk - elf_bss;
				if (clear_user((void __user *)elf_bss +
							load_bias, nbyte)) {
					/*
					 * This bss-zeroing can fail if the ELF
					 * file specifies odd protections. So
					 * we don't check the return value
					 */
				}
			}
		}

		if (elf_ppnt->p_flags & PF_R)
			elf_prot |= PROT_READ;
		if (elf_ppnt->p_flags & PF_W)
			elf_prot |= PROT_WRITE;
		if (elf_ppnt->p_flags & PF_X)
			elf_prot |= PROT_EXEC;

		elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;

		vaddr = elf_ppnt->p_vaddr;
		/*
		 * If we are loading ET_EXEC or we have already performed
		 * the ET_DYN load_addr calculations, proceed normally.
		 */
		if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
			elf_flags |= MAP_FIXED;
		} else if (loc->elf_ex.e_type == ET_DYN) {
			/*
			 * This logic is run once for the first LOAD Program
			 * Header for ET_DYN binaries to calculate the
			 * randomization (load_bias) for all the LOAD
			 * Program Headers, and to calculate the entire
			 * size of the ELF mapping (total_size). (Note that
			 * load_addr_set is set to true later once the
			 * initial mapping is performed.)
			 *
			 * There are effectively two types of ET_DYN
			 * binaries: programs (i.e. PIE: ET_DYN with INTERP)
			 * and loaders (ET_DYN without INTERP, since they
			 * _are_ the ELF interpreter). The loaders must
			 * be loaded away from programs since the program
			 * may otherwise collide with the loader (especially
			 * for ET_EXEC which does not have a randomized
			 * position). For example to handle invocations of
			 * "./ld.so someprog" to test out a new version of
			 * the loader, the subsequent program that the
			 * loader loads must avoid the loader itself, so
			 * they cannot share the same load range. Sufficient
			 * room for the brk must be allocated with the
			 * loader as well, since brk must be available with
			 * the loader.
			 *
			 * Therefore, programs are loaded offset from
			 * ELF_ET_DYN_BASE and loaders are loaded into the
			 * independently randomized mmap region (0 load_bias
			 * without MAP_FIXED).
			 */
			if (elf_interpreter) {
				load_bias = ELF_ET_DYN_BASE;
				if (current->flags & PF_RANDOMIZE)
					load_bias += arch_mmap_rnd();
				elf_flags |= MAP_FIXED;
			} else
				load_bias = 0;

			/*
			 * Since load_bias is used for all subsequent loading
			 * calculations, we must lower it by the first vaddr
			 * so that the remaining calculations based on the
			 * ELF vaddrs will be correctly offset. The result
			 * is then page aligned.
			 */
			load_bias = ELF_PAGESTART(load_bias - vaddr);

			total_size = total_mapping_size(elf_phdata,
							loc->elf_ex.e_phnum);
			if (!total_size) {
				retval = -EINVAL;
				goto out_free_dentry;
			}
		}

		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
				elf_prot, elf_flags, total_size);
		if (BAD_ADDR(error)) {
			retval = IS_ERR((void *)error) ?
				PTR_ERR((void*)error) : -EINVAL;
			goto out_free_dentry;
		}

		if (!load_addr_set) {
			load_addr_set = 1;
			load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
			if (loc->elf_ex.e_type == ET_DYN) {
				load_bias += error -
				             ELF_PAGESTART(load_bias + vaddr);
				load_addr += load_bias;
				reloc_func_desc = load_bias;
			}
		}
		k = elf_ppnt->p_vaddr;
		if (k < start_code)
			start_code = k;
		if (start_data < k)
			start_data = k;

		/*
		 * Check to see if the section's size will overflow the
		 * allowed task size. Note that p_filesz must always be
		 * <= p_memsz so it is only necessary to check p_memsz.
		 */
		if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
		    elf_ppnt->p_memsz > TASK_SIZE ||
		    TASK_SIZE - elf_ppnt->p_memsz < k) {
			/* set_brk can never work. Avoid overflows. */
			retval = -EINVAL;
			goto out_free_dentry;
		}

		k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;

		if (k > elf_bss)
			elf_bss = k;
		if ((elf_ppnt->p_flags & PF_X) && end_code < k)
			end_code = k;
		if (end_data < k)
			end_data = k;
		k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
		if (k > elf_brk) {
			bss_prot = elf_prot;
			elf_brk = k;
		}
	}

	loc->elf_ex.e_entry += load_bias;
	elf_bss += load_bias;
	elf_brk += load_bias;
	start_code += load_bias;
	end_code += load_bias;
	start_data += load_bias;
	end_data += load_bias;

	/* Calling set_brk effectively mmaps the pages that we need
	 * for the bss and break sections.  We must do this before
	 * mapping in the interpreter, to make sure it doesn't wind
	 * up getting placed where the bss needs to go.
	 */
	retval = set_brk(elf_bss, elf_brk, bss_prot);
	if (retval)
		goto out_free_dentry;
	if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
		retval = -EFAULT; /* Nobody gets to see this, but.. */
		goto out_free_dentry;
	}

	if (elf_interpreter) {
		unsigned long interp_map_addr = 0;

		elf_entry = load_elf_interp(&loc->interp_elf_ex,
					    interpreter,
					    &interp_map_addr,
					    load_bias, interp_elf_phdata);
		if (!IS_ERR((void *)elf_entry)) {
			/*
			 * load_elf_interp() returns relocation
			 * adjustment
			 */
			interp_load_addr = elf_entry;
			elf_entry += loc->interp_elf_ex.e_entry;
		}
		if (BAD_ADDR(elf_entry)) {
			retval = IS_ERR((void *)elf_entry) ?
					(int)elf_entry : -EINVAL;
			goto out_free_dentry;
		}
		reloc_func_desc = interp_load_addr;

		allow_write_access(interpreter);
		fput(interpreter);
		kfree(elf_interpreter);
	} else {
		elf_entry = loc->elf_ex.e_entry;
		if (BAD_ADDR(elf_entry)) {
			retval = -EINVAL;
			goto out_free_dentry;
		}
	}

	kfree(interp_elf_phdata);
	kfree(elf_phdata);

	set_binfmt(&elf_format);

#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
	retval = arch_setup_additional_pages(bprm, !!elf_interpreter);
	if (retval < 0)
		goto out;
#endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */

	retval = create_elf_tables(bprm, &loc->elf_ex,
			  load_addr, interp_load_addr);
	if (retval < 0)
		goto out;
	/* N.B. passed_fileno might not be initialized? */
	current->mm->end_code = end_code;
	current->mm->start_code = start_code;
	current->mm->start_data = start_data;
	current->mm->end_data = end_data;
	current->mm->start_stack = bprm->p;

	if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) {
		current->mm->brk = current->mm->start_brk =
			arch_randomize_brk(current->mm);
#ifdef compat_brk_randomized
		current->brk_randomized = 1;
#endif
	}

	if (current->personality & MMAP_PAGE_ZERO) {
		/* Why this, you ask???  Well SVr4 maps page 0 as read-only,
		   and some applications "depend" upon this behavior.
		   Since we do not have the power to recompile these, we
		   emulate the SVr4 behavior. Sigh. */
		error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
				MAP_FIXED | MAP_PRIVATE, 0);
	}

#ifdef ELF_PLAT_INIT
	/*
	 * The ABI may specify that certain registers be set up in special
	 * ways (on i386 %edx is the address of a DT_FINI function, for
	 * example.  In addition, it may also specify (eg, PowerPC64 ELF)
	 * that the e_entry field is the address of the function descriptor
	 * for the startup routine, rather than the address of the startup
	 * routine itself.  This macro performs whatever initialization to
	 * the regs structure is required as well as any relocations to the
	 * function descriptor entries when executing dynamically links apps.
	 */
	ELF_PLAT_INIT(regs, reloc_func_desc);
#endif

	start_thread(regs, elf_entry, bprm->p);
	retval = 0;
out:
	kfree(loc);
out_ret:
	return retval;

	/* error cleanup */
out_free_dentry:
	kfree(interp_elf_phdata);
	allow_write_access(interpreter);
	if (interpreter)
		fput(interpreter);
out_free_interp:
	kfree(elf_interpreter);
out_free_ph:
	kfree(elf_phdata);
	goto out;
}

Project: linux
File: binfmt_elf.c

static int fill_thread_core_info(struct elf_thread_core_info *t,
				 const struct user_regset_view *view,
				 long signr, size_t *total)
{
	unsigned int i;
	unsigned int regset_size = view->regsets[0].n * view->regsets[0].size;

	/*
	 * NT_PRSTATUS is the one special case, because the regset data
	 * goes into the pr_reg field inside the note contents, rather
	 * than being the whole note contents.  We fill the reset in here.
	 * We assume that regset 0 is NT_PRSTATUS.
	 */
	fill_prstatus(&t->prstatus, t->task, signr);
	(void) view->regsets[0].get(t->task, &view->regsets[0], 0, regset_size,
				    &t->prstatus.pr_reg, NULL);

	fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
		  PRSTATUS_SIZE(t->prstatus, regset_size), &t->prstatus);
	*total += notesize(&t->notes[0]);

	do_thread_regset_writeback(t->task, &view->regsets[0]);

	/*
	 * Each other regset might generate a note too.  For each regset
	 * that has no core_note_type or is inactive, we leave t->notes[i]
	 * all zero and we'll know to skip writing it later.
	 */
	for (i = 1; i < view->n; ++i) {
		const struct user_regset *regset = &view->regsets[i];
		do_thread_regset_writeback(t->task, regset);
		if (regset->core_note_type && regset->get &&
		    (!regset->active || regset->active(t->task, regset))) {
			int ret;
			size_t size = regset->n * regset->size;
			void *data = kmalloc(size, GFP_KERNEL);
			if (unlikely(!data))
				return 0;
			ret = regset->get(t->task, regset,
					  0, size, data, NULL);
			if (unlikely(ret))
				kfree(data);
			else {
				if (regset->core_note_type != NT_PRFPREG)
					fill_note(&t->notes[i], "LINUX",
						  regset->core_note_type,
						  size, data);
				else {
					SET_PR_FPVALID(&t->prstatus,
							1, regset_size);
					fill_note(&t->notes[i], "CORE",
						  NT_PRFPREG, size, data);
				}
				*total += notesize(&t->notes[i]);
			}
		}
	}

	return 1;
}

Project: linux
File: binfmt_elf.c

static int elf_core_dump(struct coredump_params *cprm)
{
	int has_dumped = 0;
	mm_segment_t fs;
	int segs, i;
	size_t vma_data_size = 0;
	struct vm_area_struct *vma, *gate_vma;
	struct elfhdr *elf = NULL;
	loff_t offset = 0, dataoff;
	struct elf_note_info info = { };
	struct elf_phdr *phdr4note = NULL;
	struct elf_shdr *shdr4extnum = NULL;
	Elf_Half e_phnum;
	elf_addr_t e_shoff;
	elf_addr_t *vma_filesz = NULL;

	/*
	 * We no longer stop all VM operations.
	 * 
	 * This is because those proceses that could possibly change map_count
	 * or the mmap / vma pages are now blocked in do_exit on current
	 * finishing this core dump.
	 *
	 * Only ptrace can touch these memory addresses, but it doesn't change
	 * the map_count or the pages allocated. So no possibility of crashing
	 * exists while dumping the mm->vm_next areas to the core file.
	 */
  
	/* alloc memory for large data structures: too large to be on stack */
	elf = kmalloc(sizeof(*elf), GFP_KERNEL);
	if (!elf)
		goto out;
	/*
	 * The number of segs are recored into ELF header as 16bit value.
	 * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
	 */
	segs = current->mm->map_count;
	segs += elf_core_extra_phdrs();

	gate_vma = get_gate_vma(current->mm);
	if (gate_vma != NULL)
		segs++;

	/* for notes section */
	segs++;

	/* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
	 * this, kernel supports extended numbering. Have a look at
	 * include/linux/elf.h for further information. */
	e_phnum = segs > PN_XNUM ? PN_XNUM : segs;

	/*
	 * Collect all the non-memory information about the process for the
	 * notes.  This also sets up the file header.
	 */
	if (!fill_note_info(elf, e_phnum, &info, cprm->siginfo, cprm->regs))
		goto cleanup;

	has_dumped = 1;

	fs = get_fs();
	set_fs(KERNEL_DS);

	offset += sizeof(*elf);				/* Elf header */
	offset += segs * sizeof(struct elf_phdr);	/* Program headers */

	/* Write notes phdr entry */
	{
		size_t sz = get_note_info_size(&info);

		sz += elf_coredump_extra_notes_size();

		phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
		if (!phdr4note)
			goto end_coredump;

		fill_elf_note_phdr(phdr4note, sz, offset);
		offset += sz;
	}

	dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);

	if (segs - 1 > ULONG_MAX / sizeof(*vma_filesz))
		goto end_coredump;
	vma_filesz = vmalloc((segs - 1) * sizeof(*vma_filesz));
	if (!vma_filesz)
		goto end_coredump;

	for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
			vma = next_vma(vma, gate_vma)) {
		unsigned long dump_size;

		dump_size = vma_dump_size(vma, cprm->mm_flags);
		vma_filesz[i++] = dump_size;
		vma_data_size += dump_size;
	}

	offset += vma_data_size;
	offset += elf_core_extra_data_size();
	e_shoff = offset;

	if (e_phnum == PN_XNUM) {
		shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
		if (!shdr4extnum)
			goto end_coredump;
		fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
	}

	offset = dataoff;

	if (!dump_emit(cprm, elf, sizeof(*elf)))
		goto end_coredump;

	if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
		goto end_coredump;

	/* Write program headers for segments dump */
	for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
			vma = next_vma(vma, gate_vma)) {
		struct elf_phdr phdr;

		phdr.p_type = PT_LOAD;
		phdr.p_offset = offset;
		phdr.p_vaddr = vma->vm_start;
		phdr.p_paddr = 0;
		phdr.p_filesz = vma_filesz[i++];
		phdr.p_memsz = vma->vm_end - vma->vm_start;
		offset += phdr.p_filesz;
		phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
		if (vma->vm_flags & VM_WRITE)
			phdr.p_flags |= PF_W;
		if (vma->vm_flags & VM_EXEC)
			phdr.p_flags |= PF_X;
		phdr.p_align = ELF_EXEC_PAGESIZE;

		if (!dump_emit(cprm, &phdr, sizeof(phdr)))
			goto end_coredump;
	}

	if (!elf_core_write_extra_phdrs(cprm, offset))
		goto end_coredump;

 	/* write out the notes section */
	if (!write_note_info(&info, cprm))
		goto end_coredump;

	if (elf_coredump_extra_notes_write(cprm))
		goto end_coredump;

	/* Align to page */
	if (!dump_skip(cprm, dataoff - cprm->pos))
		goto end_coredump;

	for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
			vma = next_vma(vma, gate_vma)) {
		unsigned long addr;
		unsigned long end;

		end = vma->vm_start + vma_filesz[i++];

		for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
			struct page *page;
			int stop;

			page = get_dump_page(addr);
			if (page) {
				void *kaddr = kmap(page);
				stop = !dump_emit(cprm, kaddr, PAGE_SIZE);
				kunmap(page);
				put_page(page);
			} else
				stop = !dump_skip(cprm, PAGE_SIZE);
			if (stop)
				goto end_coredump;
		}
	}
	dump_truncate(cprm);

	if (!elf_core_write_extra_data(cprm))
		goto end_coredump;

	if (e_phnum == PN_XNUM) {
		if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
			goto end_coredump;
	}

end_coredump:
	set_fs(fs);

cleanup:
	free_note_info(&info);
	kfree(shdr4extnum);
	vfree(vma_filesz);
	kfree(phdr4note);
	kfree(elf);
out:
	return has_dumped;
}

Project: linux
File: binfmt_elf.c

static int set_brk(unsigned long start, unsigned long end, int prot)
{
	start = ELF_PAGEALIGN(start);
	end = ELF_PAGEALIGN(end);
	if (end > start) {
		/*
		 * Map the last of the bss segment.
		 * If the header is requesting these pages to be
		 * executable, honour that (ppc32 needs this).
		 */
		int error = vm_brk_flags(start, end - start,
				prot & PROT_EXEC ? VM_EXEC : 0);
		if (error)
			return error;
	}
	current->mm->start_brk = current->mm->brk = end;
	return 0;
}

Project: linux
File: binfmt_elf.c

static void fill_prstatus(struct elf_prstatus *prstatus,
		struct task_struct *p, long signr)
{
	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
	prstatus->pr_sigpend = p->pending.signal.sig[0];
	prstatus->pr_sighold = p->blocked.sig[0];
	rcu_read_lock();
	prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
	rcu_read_unlock();
	prstatus->pr_pid = task_pid_vnr(p);
	prstatus->pr_pgrp = task_pgrp_vnr(p);
	prstatus->pr_sid = task_session_vnr(p);
	if (thread_group_leader(p)) {
		struct task_cputime cputime;

		/*
		 * This is the record for the group leader.  It shows the
		 * group-wide total, not its individual thread total.
		 */
		thread_group_cputime(p, &cputime);
		prstatus->pr_utime = ns_to_timeval(cputime.utime);
		prstatus->pr_stime = ns_to_timeval(cputime.stime);
	} else {
		u64 utime, stime;

		task_cputime(p, &utime, &stime);
		prstatus->pr_utime = ns_to_timeval(utime);
		prstatus->pr_stime = ns_to_timeval(stime);
	}

	prstatus->pr_cutime = ns_to_timeval(p->signal->cutime);
	prstatus->pr_cstime = ns_to_timeval(p->signal->cstime);
}