[PATCH net-next v3 7/9] net: inet6: do not leave a dangling sk pointer in inet6_create()

[Ignat Korchagin]

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 <ig...@cloudflare.com>
---
 net/ipv6/af_inet6.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index ba69b86f1c7d..f60ec8b0f8ea 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -252,31 +252,29 @@ static int inet6_create(struct net *net, struct socket 
*sock, int 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,
-- 
2.39.5