linux-kernel - [PATCH] x_25: Adding a null pointer dereference check to the x25

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Message-ID: <20240313132214.48716-1-m.lobanov@rosalinux.ru>
Date: Wed, 13 Mar 2024 09:22:08 -0400
From: Mikhail Lobanov <m.lobanov@...alinux.ru>
To: Martin Schiller <ms@....tdt.de>
Cc: Mikhail Lobanov <m.lobanov@...alinux.ru>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	linux-x25@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] x_25: Adding a null pointer dereference check to the x25_accept() function

To avoid the problem of dereferencing the null pointer in the x25_accept()
function, you need to add an additional check that the pointer skb is
not equal to NULL.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Mikhail Lobanov <m.lobanov@...alinux.ru>
---
 net/x25/af_x25.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
index f7a7c7798c3b..91bc5994cef6 100644
--- a/net/x25/af_x25.c
+++ b/net/x25/af_x25.c
@@ -896,7 +896,7 @@ static int x25_accept(struct socket *sock, struct socket *newsock, int flags,
 		goto out2;
 	skb = skb_dequeue(&sk->sk_receive_queue);
 	rc = -EINVAL;
-	if (!skb->sk)
+	if (!skb || !skb->sk)
 		goto out2;
 	newsk		 = skb->sk;
 	sock_graft(newsk, newsock);
-- 
2.43.0