[PATCH 4.9 57/62] sctp: not bind the socket in sctp_connect

Greg Kroah-Hartman
2019-11-04T22:25:31Z

From: Xin Long <lucien.xin@gmail.com>

commit 9b6c08878e23adb7cc84bdca94d8a944b03f099e upstream.

Now when sctp_connect() is called with a wrong sa_family, it binds
to a port but doesn't set bp->port, then sctp_get_af_specific will
return NULL and sctp_connect() returns -EINVAL.

Then if sctp_bind() is called to bind to another port, the last
port it has bound will leak due to bp->port is NULL by then.

sctp_connect() doesn't need to bind ports, as later __sctp_connect
will do it if bp->port is NULL. So remove it from sctp_connect().
While at it, remove the unnecessary sockaddr.sa_family len check
as it's already done in sctp_inet_connect.

Fixes: 644fbdeacf1d ("sctp: fix the issue that flags are ignored when using kernel_connect")
Reported-by: syzbot+079bf326b38072f849d9@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/sctp/socket.c | 21 ++-------------------
1 file changed, 2 insertions(+), 19 deletions(-)

--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3981,34 +3981,17 @@ out_nounlock:
static int sctp_connect(struct sock *sk, struct sockaddr *addr,
int addr_len, int flags)
{
- struct inet_sock *inet = inet_sk(sk);
struct sctp_af *af;
- int err = 0;
+ int err = -EINVAL;

lock_sock(sk);
-
pr_debug("%s: sk:%p, sockaddr:%p, addr_len:%d\n", __func__, sk,
addr, addr_len);

- /* We may need to bind the socket. */
- if (!inet->inet_num) {
- if (sk->sk_prot->get_port(sk, 0)) {
- release_sock(sk);
- return -EAGAIN;
- }
- inet->inet_sport = htons(inet->inet_num);
- }
-
/* Validate addr_len before calling common connect/connectx routine. */
af = sctp_get_af_specific(addr->sa_family);
- if (!af || addr_len < af->sockaddr_len) {
- err = -EINVAL;
- } else {
- /* Pass correct addr len to common routine (so it knows there
- * is only one address being passed.
- */
+ if (af && addr_len >= af->sockaddr_len)
err = __sctp_connect(sk, addr, af->sockaddr_len, flags, NULL);
- }

release_sock(sk);
return err;