From 36893ef0b661671ee64eb37bf5f345f33d2cabb7 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Mon, 24 Jun 2024 18:36:40 -0700 Subject: [PATCH] af_unix: Don't stop recv() at consumed ex-OOB skb. Currently, recv() is stopped at a consumed OOB skb even if a new OOB skb is queued and we can ignore the old OOB skb. >>> from socket import * >>> c1, c2 = socket(AF_UNIX, SOCK_STREAM) >>> c1.send(b'hellowor', MSG_OOB) 8 >>> c2.recv(1, MSG_OOB) # consume OOB data stays at middle of recvq. b'r' >>> c1.send(b'ld', MSG_OOB) 2 >>> c2.recv(10) # recv() stops at the old consumed OOB b'hellowo' # should be 'hellowol' manage_oob() should not stop recv() at the old consumed OOB skb if there is a new OOB data queued. Note that TCP behaviour is apparently wrong in this test case because we can recv() the same OOB data twice. Without fix: # RUN msg_oob.no_peek.ex_oob_ahead_break ... # msg_oob.c:138:ex_oob_ahead_break:AF_UNIX :hellowo # msg_oob.c:139:ex_oob_ahead_break:Expected:hellowol # msg_oob.c:141:ex_oob_ahead_break:Expected ret[0] (7) == expected_len (8) # ex_oob_ahead_break: Test terminated by assertion # FAIL msg_oob.no_peek.ex_oob_ahead_break not ok 11 msg_oob.no_peek.ex_oob_ahead_break With fix: # RUN msg_oob.no_peek.ex_oob_ahead_break ... # msg_oob.c:146:ex_oob_ahead_break:AF_UNIX :hellowol # msg_oob.c:147:ex_oob_ahead_break:TCP :helloworl # OK msg_oob.no_peek.ex_oob_ahead_break ok 11 msg_oob.no_peek.ex_oob_ahead_break Fixes: 314001f0bf92 ("af_unix: Add OOB support") Signed-off-by: Kuniyuki Iwashima Signed-off-by: Paolo Abeni --- net/unix/af_unix.c | 2 +- tools/testing/selftests/net/af_unix/msg_oob.c | 16 ++++++++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index b0b97f8d0d09..07f5eaa04b5b 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2618,7 +2618,7 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk, spin_lock(&sk->sk_receive_queue.lock); - if (copied) { + if (copied && (!u->oob_skb || skb == u->oob_skb)) { skb = NULL; } else if (flags & MSG_PEEK) { skb = skb_peek_next(skb, &sk->sk_receive_queue); diff --git a/tools/testing/selftests/net/af_unix/msg_oob.c b/tools/testing/selftests/net/af_unix/msg_oob.c index 46e92d06b0a3..acf4bd0afe17 100644 --- a/tools/testing/selftests/net/af_unix/msg_oob.c +++ b/tools/testing/selftests/net/af_unix/msg_oob.c @@ -288,4 +288,20 @@ TEST_F(msg_oob, ex_oob_drop_2) } } +TEST_F(msg_oob, ex_oob_ahead_break) +{ + sendpair("hello", 5, MSG_OOB); + sendpair("wor", 3, MSG_OOB); + + recvpair("r", 1, 1, MSG_OOB); + + sendpair("ld", 2, MSG_OOB); + + tcp_incompliant { + recvpair("hellowol", 8, 10, 0); /* TCP recv()s "helloworl", why "r" ?? */ + } + + recvpair("d", 1, 1, MSG_OOB); +} + TEST_HARNESS_MAIN