1 files changed, 26 insertions, 25 deletions

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 971282b6f6a3..826e09938bff 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1340,7 +1340,6 @@ static void unix_destruct_scm(struct sk_buff *skb)
 	struct scm_cookie scm;
 	memset(&scm, 0, sizeof(scm));
 	scm.pid  = UNIXCB(skb).pid;
-	scm.cred = UNIXCB(skb).cred;
 	if (UNIXCB(skb).fp)
 		unix_detach_fds(&scm, skb);
 
@@ -1391,8 +1390,8 @@ static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool sen
 	int err = 0;
 
 	UNIXCB(skb).pid  = get_pid(scm->pid);
-	if (scm->cred)
-		UNIXCB(skb).cred = get_cred(scm->cred);
+	UNIXCB(skb).uid = scm->creds.uid;
+	UNIXCB(skb).gid = scm->creds.gid;
 	UNIXCB(skb).fp = NULL;
 	if (scm->fp && send_fds)
 		err = unix_attach_fds(scm, skb);
@@ -1409,13 +1408,13 @@ static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool sen
 static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
 			    const struct sock *other)
 {
-	if (UNIXCB(skb).cred)
+	if (UNIXCB(skb).pid)
 		return;
 	if (test_bit(SOCK_PASSCRED, &sock->flags) ||
-	    (other->sk_socket &&
-	    test_bit(SOCK_PASSCRED, &other->sk_socket->flags))) {
+	    !other->sk_socket ||
+	    test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
 		UNIXCB(skb).pid  = get_pid(task_tgid(current));
-		UNIXCB(skb).cred = get_current_cred();
+		current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
 	}
 }
 
@@ -1819,7 +1818,7 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
 		siocb->scm = &tmp_scm;
 		memset(&tmp_scm, 0, sizeof(tmp_scm));
 	}
-	scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
+	scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
 	unix_set_secdata(siocb->scm, skb);
 
 	if (!(flags & MSG_PEEK)) {
@@ -1859,10 +1858,10 @@ out:
 }
 
 /*
- *	Sleep until data has arrive. But check for races..
+ *	Sleep until more data has arrived. But check for races..
  */
-
-static long unix_stream_data_wait(struct sock *sk, long timeo)
+static long unix_stream_data_wait(struct sock *sk, long timeo,
+				  struct sk_buff *last)
 {
 	DEFINE_WAIT(wait);
 
@@ -1871,7 +1870,7 @@ static long unix_stream_data_wait(struct sock *sk, long timeo)
 	for (;;) {
 		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 
-		if (!skb_queue_empty(&sk->sk_receive_queue) ||
+		if (skb_peek_tail(&sk->sk_receive_queue) != last ||
 		    sk->sk_err ||
 		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
 		    signal_pending(current) ||
@@ -1890,8 +1889,6 @@ static long unix_stream_data_wait(struct sock *sk, long timeo)
 	return timeo;
 }
 
-
-
 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
 			       struct msghdr *msg, size_t size,
 			       int flags)
@@ -1936,14 +1933,12 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
 		goto out;
 	}
 
-	skip = sk_peek_offset(sk, flags);
-
 	do {
 		int chunk;
-		struct sk_buff *skb;
+		struct sk_buff *skb, *last;
 
 		unix_state_lock(sk);
-		skb = skb_peek(&sk->sk_receive_queue);
+		last = skb = skb_peek(&sk->sk_receive_queue);
 again:
 		if (skb == NULL) {
 			unix_sk(sk)->recursion_level = 0;
@@ -1966,7 +1961,7 @@ again:
 				break;
 			mutex_unlock(&u->readlock);
 
-			timeo = unix_stream_data_wait(sk, timeo);
+			timeo = unix_stream_data_wait(sk, timeo, last);
 
 			if (signal_pending(current)
 			    ||  mutex_lock_interruptible(&u->readlock)) {
@@ -1980,10 +1975,13 @@ again:
 			break;
 		}
 
-		if (skip >= skb->len) {
+		skip = sk_peek_offset(sk, flags);
+		while (skip >= skb->len) {
 			skip -= skb->len;
+			last = skb;
 			skb = skb_peek_next(skb, &sk->sk_receive_queue);
-			goto again;
+			if (!skb)
+				goto again;
 		}
 
 		unix_state_unlock(sk);
@@ -1991,11 +1989,12 @@ again:
 		if (check_creds) {
 			/* Never glue messages from different writers */
 			if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
-			    (UNIXCB(skb).cred != siocb->scm->cred))
+			    !uid_eq(UNIXCB(skb).uid, siocb->scm->creds.uid) ||
+			    !gid_eq(UNIXCB(skb).gid, siocb->scm->creds.gid))
 				break;
-		} else {
+		} else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
 			/* Copy credentials */
-			scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
+			scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
 			check_creds = 1;
 		}
 
@@ -2196,7 +2195,9 @@ static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
 
 	/* exceptional events? */
 	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
-		mask |= POLLERR;
+		mask |= POLLERR |
+			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
+
 	if (sk->sk_shutdown & RCV_SHUTDOWN)
 		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
 	if (sk->sk_shutdown == SHUTDOWN_MASK)