On error can_create() frees the allocated sk object, but sock_init_data()
has already attached it to the provided sock object. This will leave a
dangling sk pointer in the sock object and may cause use-after-free later.

Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
 net/can/af_can.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/can/af_can.c b/net/can/af_can.c
index 707576eeeb58..01f3fbb3b67d 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -171,6 +171,7 @@ static int can_create(struct net *net, struct socket *sock, int protocol,
 		/* release sk on errors */
 		sock_orphan(sk);
 		sock_put(sk);
+		sock->sk = NULL;
 	}
 
  errout:
-- 
2.39.5

On 14.10.2024 16:38:03, Ignat Korchagin wrote:
> On error can_create() frees the allocated sk object, but sock_init_data()
> has already attached it to the provided sock object. This will leave a
> dangling sk pointer in the sock object and may cause use-after-free later.
> 
> Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
> Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>

Reviewed-by: Marc Kleine-Budde <mkl@pengutronix.de>

regards,
Marc

-- 
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From: Ignat Korchagin <ignat@cloudflare.com>
Date: Mon, 14 Oct 2024 16:38:03 +0100
> On error can_create() frees the allocated sk object, but sock_init_data()
> has already attached it to the provided sock object. This will leave a
> dangling sk pointer in the sock object and may cause use-after-free later.
> 
> Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
> Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>

Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>