Commit ba093a6d authored Aug 02, 2016 by Kees Cook Committed by Linus Torvalds Aug 02, 2016

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: Kees Cook <keescook@chromium.org>
Reported-by: Hector 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus 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;

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