netdev - [PATCH v2] Fix NULL pointer dereference in cn

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Date: Fri, 20 Oct 2023 16:40:58 -0700
From: Anjali Kulkarni <anjali.k.kulkarni@...cle.com>
To: linux-kernel@...r.kernel.org
Cc: davem@...emloft.net, Liam.Howlett@...cle.com, netdev@...r.kernel.org,
        oliver.sang@...el.com, kuba@...nel.org, horms@...nel.org,
        anjali.k.kulkarni@...cle.com
Subject: [PATCH v2] Fix NULL pointer dereference in cn_filter()

Check that sk_user_data is not NULL, else return from cn_filter().
Could not reproduce this issue, but Oliver Sang verified it has fixed
the "Closes" problem below.

Fixes: 2aa1f7a1f47c ("connector/cn_proc: Add filtering to fix some bugs")
Reported-by: kernel test robot <oliver.sang@...el.com>
Closes: https://lore.kernel.org/oe-lkp/202309201456.84c19e27-oliver.sang@intel.com/
Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@...cle.com>
---
 drivers/connector/cn_proc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index 05d562e9c8b1..44b19e696176 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -54,7 +54,7 @@ static int cn_filter(struct sock *dsk, struct sk_buff *skb, void *data)
 	enum proc_cn_mcast_op mc_op;
 	uintptr_t val;
 
-	if (!dsk || !data)
+	if (!dsk || !dsk->sk_user_data || !data)
 		return 0;
 
 	ptr = (__u32 *)data;
-- 
2.42.0