net: inet6: do not leave a dangling sk pointer in inet6_create()

sock_init_data() attaches the allocated sk pointer to the provided sock
object. If inet6_create() fails later, the sk object is released, but the
sock object retains the dangling sk pointer, which may cause use-after-free
later.

Clear the sock sk pointer on error.

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/20241014153808.51894-8-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index ba69b86f1c7d5e8d9c8b02f3e70a95d913082701..f60ec8b0f8ea40b2d635d802a3bc4f9b9d844417 100644 (file)
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -252,31 +252,29 @@ lookup_protocol:
                 */
                inet->inet_sport = htons(inet->inet_num);
                err = sk->sk_prot->hash(sk);
-               if (err) {
-                       sk_common_release(sk);
-                       goto out;
-               }
+               if (err)
+                       goto out_sk_release;
        }
        if (sk->sk_prot->init) {
                err = sk->sk_prot->init(sk);
-               if (err) {
-                       sk_common_release(sk);
-                       goto out;
-               }
+               if (err)
+                       goto out_sk_release;
        }
 
        if (!kern) {
                err = BPF_CGROUP_RUN_PROG_INET_SOCK(sk);
-               if (err) {
-                       sk_common_release(sk);
-                       goto out;
-               }
+               if (err)
+                       goto out_sk_release;
        }
 out:
        return err;
 out_rcu_unlock:
        rcu_read_unlock();
        goto out;
+out_sk_release:
+       sk_common_release(sk);
+       sock->sk = NULL;
+       goto out;
 }
 
 static int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,