net/smc: Fix af_ops of child socket pointing to released memory
Child sockets may inherit the af_ops from the parent listen socket.
When the listen socket is released then the af_ops of the child socket
points to released memory.
Solve that by restoring the original af_ops for child sockets which
inherited the parent af_ops. And clear any inherited user_data of the
parent socket.
Fixes: 8270d9c21041 ("net/smc: Limit backlog connections")
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: D. Wythe <alibuda@linux.alibaba.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index f0d118e..14ddc40 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -121,6 +121,7 @@ static struct sock *smc_tcp_syn_recv_sock(const struct sock *sk,
bool *own_req)
{
struct smc_sock *smc;
+ struct sock *child;
smc = smc_clcsock_user_data(sk);
@@ -134,8 +135,17 @@ static struct sock *smc_tcp_syn_recv_sock(const struct sock *sk,
}
/* passthrough to original syn recv sock fct */
- return smc->ori_af_ops->syn_recv_sock(sk, skb, req, dst, req_unhash,
- own_req);
+ child = smc->ori_af_ops->syn_recv_sock(sk, skb, req, dst, req_unhash,
+ own_req);
+ /* child must not inherit smc or its ops */
+ if (child) {
+ rcu_assign_sk_user_data(child, NULL);
+
+ /* v4-mapped sockets don't inherit parent ops. Don't restore. */
+ if (inet_csk(child)->icsk_af_ops == inet_csk(sk)->icsk_af_ops)
+ inet_csk(child)->icsk_af_ops = smc->ori_af_ops;
+ }
+ return child;
drop:
dst_release(dst);
