1 files changed, 29 insertions, 16 deletions

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index ec68e1c05b85..e6d9d1014ed2 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1378,11 +1378,17 @@ static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
 	return max_level;
 }
 
-static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
+static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb,
+			   bool send_fds, bool ref)
 {
 	int err = 0;
-	UNIXCB(skb).pid  = get_pid(scm->pid);
-	UNIXCB(skb).cred = get_cred(scm->cred);
+	if (ref) {
+		UNIXCB(skb).pid  = get_pid(scm->pid);
+		UNIXCB(skb).cred = get_cred(scm->cred);
+	} else {
+		UNIXCB(skb).pid  = scm->pid;
+		UNIXCB(skb).cred = scm->cred;
+	}
 	UNIXCB(skb).fp = NULL;
 	if (scm->fp && send_fds)
 		err = unix_attach_fds(scm, skb);
@@ -1407,7 +1413,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
 	int namelen = 0; /* fake GCC */
 	int err;
 	unsigned hash;
-	struct sk_buff *skb;
+	struct sk_buff *skb = NULL;
 	long timeo;
 	struct scm_cookie tmp_scm;
 	int max_level;
@@ -1448,7 +1454,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
 	if (skb == NULL)
 		goto out;
 
-	err = unix_scm_to_skb(siocb->scm, skb, true);
+	err = unix_scm_to_skb(siocb->scm, skb, true, false);
 	if (err < 0)
 		goto out_free;
 	max_level = err + 1;
@@ -1544,7 +1550,7 @@ restart:
 	unix_state_unlock(other);
 	other->sk_data_ready(other, len);
 	sock_put(other);
-	scm_destroy(siocb->scm);
+	scm_release(siocb->scm);
 	return len;
 
 out_unlock:
@@ -1554,7 +1560,8 @@ out_free:
 out:
 	if (other)
 		sock_put(other);
-	scm_destroy(siocb->scm);
+	if (skb == NULL)
+		scm_destroy(siocb->scm);
 	return err;
 }
 
@@ -1566,7 +1573,7 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 	struct sock *sk = sock->sk;
 	struct sock *other = NULL;
 	int err, size;
-	struct sk_buff *skb;
+	struct sk_buff *skb = NULL;
 	int sent = 0;
 	struct scm_cookie tmp_scm;
 	bool fds_sent = false;
@@ -1631,11 +1638,11 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 		size = min_t(int, size, skb_tailroom(skb));
 
 
-		/* Only send the fds in the first buffer */
-		err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
+		/* Only send the fds and no ref to pid in the first buffer */
+		err = unix_scm_to_skb(siocb->scm, skb, !fds_sent, fds_sent);
 		if (err < 0) {
 			kfree_skb(skb);
-			goto out_err;
+			goto out;
 		}
 		max_level = err + 1;
 		fds_sent = true;
@@ -1643,7 +1650,7 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 		err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
 		if (err) {
 			kfree_skb(skb);
-			goto out_err;
+			goto out;
 		}
 
 		unix_state_lock(other);
@@ -1660,7 +1667,10 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 		sent += size;
 	}
 
-	scm_destroy(siocb->scm);
+	if (skb)
+		scm_release(siocb->scm);
+	else
+		scm_destroy(siocb->scm);
 	siocb->scm = NULL;
 
 	return sent;
@@ -1673,7 +1683,9 @@ pipe_err:
 		send_sig(SIGPIPE, current, 0);
 	err = -EPIPE;
 out_err:
-	scm_destroy(siocb->scm);
+	if (skb == NULL)
+		scm_destroy(siocb->scm);
+out:
 	siocb->scm = NULL;
 	return sent ? : err;
 }
@@ -1777,7 +1789,7 @@ 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_noref(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
 	unix_set_secdata(siocb->scm, skb);
 
 	if (!(flags & MSG_PEEK)) {
@@ -1939,7 +1951,8 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
 			}
 		} else {
 			/* Copy credentials */
-			scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
+			scm_set_cred_noref(siocb->scm, UNIXCB(skb).pid,
+					   UNIXCB(skb).cred);
 			check_creds = 1;
 		}