Bluetooth: L2CAP: do not leave dangling sk pointer on error in l2cap_sock_create()

[ Upstream commit 7c4f78cdb8e7501e9f92d291a7d956591bf73be9 ]

bt_sock_alloc() allocates the sk object and attaches it to the provided
sock object. On error l2cap_sock_alloc() frees the sk object, but the
dangling pointer is still attached to the sock object, which may create
use-after-free in other code.

Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241014153808.51894-3-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 3a2be1b4a5743371de0df2eeff3f3ebf0fcc2e4b..57035e46f71518b369a04c2730857900a8e7d80f 100644 (file)
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1876,6 +1876,7 @@ static struct sock *l2cap_sock_alloc(struct net *net, struct socket *sock,
        chan = l2cap_chan_create();
        if (!chan) {
                sk_free(sk);
+               sock->sk = NULL;
                return NULL;
        }