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From: Chengfeng Ye <cyeaa@connect.ust.hk>
To: glider@google.com, elver@google.com, akpm@linux-foundation.org
Cc: dvyukov@google.com, kasan-dev@googlegroups.com,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Chengfeng Ye <cyeaa@connect.ust.hk>
Subject: [PATCH] mm/kfence: fix null pointer dereference on pointer meta
Date: Sat, 23 Oct 2021 10:18:02 -0700	[thread overview]
Message-ID: <20211023171802.4693-1-cyeaa@connect.ust.hk> (raw)

The pointer meta return from addr_to_metadata could be null, so
there is a potential null pointer dereference issue. Fix this
by adding a null check before dereference.

Fixes: 0ce20dd8 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Chengfeng Ye <cyeaa@connect.ust.hk>
---
 mm/kfence/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 7a97db8bc8e7..7d2ec787e921 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -811,7 +811,7 @@ void __kfence_free(void *addr)
 	 * objects once it has been freed. meta->cache may be NULL if the cache
 	 * was destroyed.
 	 */
-	if (unlikely(meta->cache && (meta->cache->flags & SLAB_TYPESAFE_BY_RCU)))
+	if (unlikely(meta && meta->cache && (meta->cache->flags & SLAB_TYPESAFE_BY_RCU)))
 		call_rcu(&meta->rcu_head, rcu_guarded_free);
 	else
 		kfence_guarded_free(addr, meta, false);
-- 
2.17.1


             reply	other threads:[~2021-10-23 17:20 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-23 17:18 Chengfeng Ye [this message]
2021-10-23 18:47 ` [PATCH] mm/kfence: fix null pointer dereference on pointer meta Marco Elver
     [not found]   ` <TYCP286MB1188F7FAA423CFA03225B3BE8A819@TYCP286MB1188.JPNP286.PROD.OUTLOOK.COM>
2021-10-25  6:00     ` Marco Elver

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