af_unix: Clean up error paths in unix_stream_sendmsg().

If we move send_sig() to the SEND_SHUTDOWN check before
the while loop, then we can reuse the same kfree_skb()
after the pipe_err_free label.

Let's gather the scattered kfree_skb()s in error paths.

While at it, some style issues are fixed, and the pipe_err_free
label is renamed to out_pipe to match other label names.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 660d8b8130cab691afcae6083d3bdf9833f119b7..d30bcd50527e9b79cd4fbf3fbf04811e39857f45 100644 (file)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2275,8 +2275,13 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
                }
        }
 
-       if (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN)
-               goto pipe_err;
+       if (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN) {
+               if (!(msg->msg_flags & MSG_NOSIGNAL))
+                       send_sig(SIGPIPE, current, 0);
+
+               err = -EPIPE;
+               goto out_err;
+       }
 
        while (sent < len) {
                size = len - sent;
@@ -2305,20 +2310,18 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 
                /* Only send the fds in the first buffer */
                err = unix_scm_to_skb(&scm, skb, !fds_sent);
-               if (err < 0) {
-                       kfree_skb(skb);
-                       goto out_err;
-               }
+               if (err < 0)
+                       goto out_free;
+
                fds_sent = true;
 
                if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {
                        skb->ip_summed = CHECKSUM_UNNECESSARY;
                        err = skb_splice_from_iter(skb, &msg->msg_iter, size,
                                                   sk->sk_allocation);
-                       if (err < 0) {
-                               kfree_skb(skb);
-                               goto out_err;
-                       }
+                       if (err < 0)
+                               goto out_free;
+
                        size = err;
                        refcount_add(size, &sk->sk_wmem_alloc);
                } else {
@@ -2326,17 +2329,15 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
                        skb->data_len = data_len;
                        skb->len = size;
                        err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
-                       if (err) {
-                               kfree_skb(skb);
-                               goto out_err;
-                       }
+                       if (err)
+                               goto out_free;
                }
 
                unix_state_lock(other);
 
                if (sock_flag(other, SOCK_DEAD) ||
                    (other->sk_shutdown & RCV_SHUTDOWN))
-                       goto pipe_err_free;
+                       goto out_pipe;
 
                maybe_add_creds(skb, sock, other);
                scm_stat_add(other, skb);
@@ -2359,13 +2360,13 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 
        return sent;
 
-pipe_err_free:
+out_pipe:
        unix_state_unlock(other);
-       kfree_skb(skb);
-pipe_err:
-       if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
+       if (!sent && !(msg->msg_flags & MSG_NOSIGNAL))
                send_sig(SIGPIPE, current, 0);
        err = -EPIPE;
+out_free:
+       kfree_skb(skb);
 out_err:
        scm_destroy(&scm);
        return sent ? : err;