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Commit ba093a6d authored by Kees Cook's avatar Kees Cook Committed by Linus Torvalds
Browse files

mm: refuse wrapped vm_brk requests 

The vm_brk() alignment calculations should refuse to overflow.  The ELF
loader depending on this, but it has been fixed now.  No other unsafe
callers have been found.

Link: http://lkml.kernel.org/r/1468014494-25291-3-git-send-email-keescook@chromium.org


Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reported-by: default avatarHector Marco-Gisbert <hecmargi@upv.es>
Cc: Ismael Ripoll Ripoll <iripoll@upv.es>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0036d1f7

mm/mmap.c

+5 −3
Original line number Diff line number Diff line
@@ -2653,16 +2653,18 @@ static inline void verify_mm_writelocked(struct mm_struct *mm) 
 *  anonymous maps.  eventually we may be able to do some

 *  brk-specific accounting here.

 */

static int do_brk(unsigned long addr, unsigned long len)

static int do_brk(unsigned long addr, unsigned long request)

{

	struct mm_struct *mm = current->mm;

	struct vm_area_struct *vma, *prev;

	unsigned long flags;

	unsigned long flags, len;

	struct rb_node **rb_link, *rb_parent;

	pgoff_t pgoff = addr >> PAGE_SHIFT;

	int error;



	len = PAGE_ALIGN(len);

	len = PAGE_ALIGN(request);

	if (len < request)

		return -ENOMEM;

	if (!len)

		return 0;