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APPLIED: [PATCH 0/3] [hardy] CVE-2011-2496

Message ID 4E954FC6.3030600@canonical.com
State New
Headers show

Commit Message

Tim Gardner Oct. 12, 2011, 8:28 a.m. UTC 
On 10/11/2011 03:17 PM, Paolo Pisati wrote:
> mm: avoid wrapping vm_pgoff in mremap() and stack expansions
>
> Following this email are 3 patches for hardy.
>
> Linus Torvalds (2):
>    mm: avoid wrapping vm_pgoff in mremap() - CVE-2011-2496
>    vm: fix vm_pgoff wrap in stack expansion - CVE-2011-2496
>
> Paolo Pisati (1):
>    vm: fix vm_pgoff wrap in upward expansion - CVE-2011-2496
>
>   mm/mmap.c   |   20 +++++++++++++-------
>   mm/mremap.c |   11 +++++++++--
>   2 files changed, 22 insertions(+), 9 deletions(-)
>

This is what was actually applied.
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Patch

From a7c538dd567bb4c34837a3afce44a4a5f80629c6 Mon Sep 17 00:00:00 2001
From: Hugh Dickins <hughd@google.com>
Date: Mon, 9 May 2011 17:44:42 -0700
Subject: [PATCH 3/3] vm: fix vm_pgoff wrap in upward expansion, CVE-2011-2496

BugLink: http://bugs.launchpad.net/bugs/869243
CVE-2011-2496

Commit a626ca6a6564 ("vm: fix vm_pgoff wrap in stack expansion") fixed
the case of an expanding mapping causing vm_pgoff wrapping when you had
downward stack expansion.  But there was another case where IA64 and
PA-RISC expand mappings: upward expansion.

This fixes that case too.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Backported from 42c36f63ac1366ab0ecc2d5717821362c259f517
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---
 mm/mmap.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index dcd3dcc..6ea8c93 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1600,9 +1600,13 @@  int expand_upwards(struct vm_area_struct *vma, unsigned long address)
 		size = address - vma->vm_start;
 		grow = (address - vma->vm_end) >> PAGE_SHIFT;
 
-		error = acct_stack_growth(vma, size, grow);
-		if (!error)
-			vma->vm_end = address;
+		error = -ENOMEM;
+		if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
+			error = acct_stack_growth(vma, size, grow);
+			if (!error) {
+				vma->vm_end = address;
+			}
+		}
 	}
 	anon_vma_unlock(vma);
 	return error;
-- 
1.7.1