Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1353860 > unrolled thread

[PATCH] mm/mempool: Avoid KASAN marking mempool posion checks as use-after-free

Back to article view | Back to linux.kernel

Contents

  [PATCH] mm/mempool: Avoid KASAN marking mempool posion checks as use-after-free Matthew Dawson <matthew@mjdsystems.ca> - 2016-03-09 07:30 +0100
    Re: [PATCH] mm/mempool: Avoid KASAN marking mempool posion checks as  use-after-free Andrey Ryabinin <aryabinin@virtuozzo.com> - 2016-03-10 15:00 +0100

#1353860 — [PATCH] mm/mempool: Avoid KASAN marking mempool posion checks as use-after-free

When removing an element from the mempool, mark it as unpoisoned in KASAN
before verifying its contents for SLUB/SLAB debugging.  Otherwise KASAN
will flag the reads checking the element use-after-free writes as
use-after-free reads.

Signed-off-by: Matthew Dawson <matthew@mjdsystems.ca>
---
 mm/mempool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mempool.c b/mm/mempool.c
index 004d42b..7924f4f 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -135,8 +135,8 @@ static void *remove_element(mempool_t *pool)
 	void *element = pool->elements[--pool->curr_nr];
 
 	BUG_ON(pool->curr_nr < 0);
-	check_element(pool, element);
 	kasan_unpoison_element(pool, element);
+	check_element(pool, element);
 	return element;
 }
 
-- 
2.7.1

[toc] | [next] | [standalone]

#1355132 — Re: [PATCH] mm/mempool: Avoid KASAN marking mempool posion checks as use-after-free

On 03/09/2016 09:16 AM, Matthew Dawson wrote:
> When removing an element from the mempool, mark it as unpoisoned in KASAN
> before verifying its contents for SLUB/SLAB debugging.  Otherwise KASAN
> will flag the reads checking the element use-after-free writes as
> use-after-free reads.
> 
> Signed-off-by: Matthew Dawson <matthew@mjdsystems.ca>

Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web