af_unix: Fix wrong ioctl(SIOCATMARK) when consumed OOB skb is at the head.

Even if OOB data is recv()ed, ioctl(SIOCATMARK) must return 1 when the
OOB skb is at the head of the receive queue and no new OOB data is queued.

Without fix:

  #  RUN           msg_oob.no_peek.oob ...
  # msg_oob.c:305:oob:Expected answ[0] (0) == oob_head (1)
  # oob: Test terminated by assertion
  #          FAIL  msg_oob.no_peek.oob
  not ok 2 msg_oob.no_peek.oob

With fix:

  #  RUN           msg_oob.no_peek.oob ...
  #            OK  msg_oob.no_peek.oob
  ok 2 msg_oob.no_peek.oob

Fixes: 314001f0bf92 ("af_unix: Add OOB support")
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 07f5eaa..142f567 100644 (file)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -3107,12 +3107,23 @@ static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 #if IS_ENABLED(CONFIG_AF_UNIX_OOB)
        case SIOCATMARK:
                {
+                       struct unix_sock *u = unix_sk(sk);
                        struct sk_buff *skb;
                        int answ = 0;
 
+                       mutex_lock(&u->iolock);
+
                        skb = skb_peek(&sk->sk_receive_queue);
-                       if (skb && skb == READ_ONCE(unix_sk(sk)->oob_skb))
-                               answ = 1;
+                       if (skb) {
+                               struct sk_buff *oob_skb = READ_ONCE(u->oob_skb);
+
+                               if (skb == oob_skb ||
+                                   (!oob_skb && !unix_skb_len(skb)))
+                                       answ = 1;
+                       }
+
+                       mutex_unlock(&u->iolock);
+
                        err = put_user(answ, (int __user *)arg);
                }
                break;

diff --git a/tools/testing/selftests/net/af_unix/msg_oob.c b/tools/testing/selftests/net/af_unix/msg_oob.c
index 28b09b3..2d00243 100644 (file)
--- a/tools/testing/selftests/net/af_unix/msg_oob.c
+++ b/tools/testing/selftests/net/af_unix/msg_oob.c
@@ -288,6 +288,26 @@ static void __setinlinepair(struct __test_metadata *_metadata,
        }
 }
 
+static void __siocatmarkpair(struct __test_metadata *_metadata,
+                            FIXTURE_DATA(msg_oob) *self,
+                            bool oob_head)
+{
+       int answ[2] = {};
+       int i;
+
+       for (i = 0; i < 2; i++) {
+               int ret;
+
+               ret = ioctl(self->fd[i * 2 + 1], SIOCATMARK, &answ[i]);
+               ASSERT_EQ(ret, 0);
+       }
+
+       ASSERT_EQ(answ[0], oob_head);
+
+       if (self->tcp_compliant)
+               ASSERT_EQ(answ[0], answ[1]);
+}
+
 #define sendpair(buf, len, flags)                                      \
        __sendpair(_metadata, self, buf, len, flags)
 
@@ -304,6 +324,9 @@ static void __setinlinepair(struct __test_metadata *_metadata,
 #define epollpair(oob_remaining)                                       \
        __epollpair(_metadata, self, oob_remaining)
 
+#define siocatmarkpair(oob_head)                                       \
+       __siocatmarkpair(_metadata, self, oob_head)
+
 #define setinlinepair()                                                        \
        __setinlinepair(_metadata, self)
 
@@ -325,9 +348,11 @@ TEST_F(msg_oob, oob)
 {
        sendpair("x", 1, MSG_OOB);
        epollpair(true);
+       siocatmarkpair(true);
 
        recvpair("x", 1, 1, MSG_OOB);
        epollpair(false);
+       siocatmarkpair(true);
 }
 
 TEST_F(msg_oob, oob_drop)
@@ -481,18 +506,40 @@ TEST_F(msg_oob, ex_oob_ahead_break)
        epollpair(false);
 }
 
+TEST_F(msg_oob, ex_oob_siocatmark)
+{
+       sendpair("hello", 5, MSG_OOB);
+       epollpair(true);
+       siocatmarkpair(false);
+
+       recvpair("o", 1, 1, MSG_OOB);
+       epollpair(false);
+       siocatmarkpair(false);
+
+       sendpair("world", 5, MSG_OOB);
+       epollpair(true);
+       siocatmarkpair(false);
+
+       recvpair("hell", 4, 4, 0);              /* Intentionally stop at ex-OOB. */
+       epollpair(true);
+       siocatmarkpair(false);
+}
+
 TEST_F(msg_oob, inline_oob)
 {
        setinlinepair();
 
        sendpair("x", 1, MSG_OOB);
        epollpair(true);
+       siocatmarkpair(true);
 
        recvpair("", -EINVAL, 1, MSG_OOB);
        epollpair(true);
+       siocatmarkpair(true);
 
        recvpair("x", 1, 1, 0);
        epollpair(false);
+       siocatmarkpair(false);
 }
 
 TEST_F(msg_oob, inline_oob_break)
@@ -591,4 +638,25 @@ TEST_F(msg_oob, inline_ex_oob_drop)
        }
 }
 
+TEST_F(msg_oob, inline_ex_oob_siocatmark)
+{
+       sendpair("hello", 5, MSG_OOB);
+       epollpair(true);
+       siocatmarkpair(false);
+
+       recvpair("o", 1, 1, MSG_OOB);
+       epollpair(false);
+       siocatmarkpair(false);
+
+       setinlinepair();
+
+       sendpair("world", 5, MSG_OOB);
+       epollpair(true);
+       siocatmarkpair(false);
+
+       recvpair("hell", 4, 4, 0);              /* Intentionally stop at ex-OOB. */
+       epollpair(true);
+       siocatmarkpair(false);
+}
+
 TEST_HARNESS_MAIN