Commit 2f8e6902 authored Jun 26, 2019 by Xin Long Committed by Greg Kroah-Hartman Nov 06, 2019

sctp: not bind the socket in sctp_connect

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>

parent f8b14107

net/sctp/socket.c

+2 −19

Original line number	Diff line number	Diff line
		@@ -3981,34 +3981,17 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname,
		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;