This is a note to let you know that I've just added the patch titled
mm: rmap: fix use-after-free in __put_anon_vma
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-rmap-fix-use-after-free-in-__put_anon_vma.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 624483f3ea82598ab0f62f1bdb9177f531ab1892 Mon Sep 17 00:00:00 2001
From: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
Date: Fri, 6 Jun 2014 19:09:30 +0400
Subject: mm: rmap: fix use-after-free in __put_anon_vma
From: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
commit 624483f3ea82598ab0f62f1bdb9177f531ab1892 upstream.
While working address sanitizer for kernel I've discovered
use-after-free bug in __put_anon_vma.
For the last anon_vma, anon_vma->root freed before child anon_vma.
Later in anon_vma_free(anon_vma) we are referencing to already freed
anon_vma->root to check rwsem.
This fixes it by freeing the child anon_vma before freeing
anon_vma->root.
Signed-off-by: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/rmap.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1721,10 +1721,9 @@ void __put_anon_vma(struct anon_vma *ano
{
struct anon_vma *root = anon_vma->root;
+ anon_vma_free(anon_vma);
if (root != anon_vma && atomic_dec_and_test(&root->refcount))
anon_vma_free(root);
-
- anon_vma_free(anon_vma);
}
#ifdef CONFIG_MIGRATION
Patches currently in stable-queue which might be from a.ryabinin@xxxxxxxxxxx are
queue-3.4/mm-rmap-fix-use-after-free-in-__put_anon_vma.patch
queue-3.4/arm-8051-1-put_user-fix-possible-data-corruption-in-put_user.patch
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