lkml.org 
[lkml]   [2021]   [Sep]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH AUTOSEL 5.10 53/53] kasan: test: avoid corrupting memory in kasan_rcu_uaf
Date
From: Andrey Konovalov <andreyknvl@gmail.com>

[ Upstream commit f16de0bcdb55bf18e2533ca625f3e4b4952f254c ]

kasan_rcu_uaf() writes to freed memory via kasan_rcu_reclaim(), which is
only safe with the GENERIC mode (as it uses quarantine). For other modes,
this test corrupts kernel memory, which might result in a crash.

Turn the write into a read.

Link: https://lkml.kernel.org/r/b6f2c3bf712d2457c783fa59498225b66a634f62.1628779805.git.andreyknvl@gmail.com
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
lib/test_kasan_module.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/test_kasan_module.c b/lib/test_kasan_module.c
index 2d68db6ae67b..1c6e06136f78 100644
--- a/lib/test_kasan_module.c
+++ b/lib/test_kasan_module.c
@@ -73,7 +73,7 @@ static noinline void __init kasan_rcu_reclaim(struct rcu_head *rp)
struct kasan_rcu_info, rcu);

kfree(fp);
- fp->i = 1;
+ ((volatile struct kasan_rcu_info *)fp)->i;
}

static noinline void __init kasan_rcu_uaf(void)
--
2.30.2
\
 
 \ /
  Last update: 2021-09-10 03:00    [W:0.186 / U:0.324 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site