1 files changed, 23 insertions, 22 deletions

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 2db702d82e7d..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)) {
                 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 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)