From: Martin Schiller <ms@dev.tdt.de>
To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org
Cc: linux-x25@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, Martin Schiller <ms@dev.tdt.de>
Subject: [PATCH net] net/x25: fix call timeouts in blocking connects
Date: Fri, 5 Aug 2022 08:18:10 +0200 [thread overview]
Message-ID: <20220805061810.10824-1-ms@dev.tdt.de> (raw)
When a userspace application starts a blocking connect(), a CALL REQUEST
is sent, the t21 timer is started and the connect is waiting in
x25_wait_for_connection_establishment(). If then for some reason the t21
timer expires before any reaction on the assigned logical channel (e.g.
CALL ACCEPT, CLEAR REQUEST), there is sent a CLEAR REQUEST and timer
t23 is started waiting for a CLEAR confirmation. If we now receive a
CLEAR CONFIRMATION from the peer, x25_disconnect() is called in
x25_state2_machine() with reason "0", which means "normal" call
clearing. This is ok, but the parameter "reason" is used as sk->sk_err
in x25_disconnect() and sock_error(sk) is evaluated in
x25_wait_for_connection_establishment() to check if the call is still
pending. As "0" is not rated as an error, the connect will stuck here
forever.
To fix this situation, also check if the sk->sk_state changed form
TCP_SYN_SENT to TCP_CLOSE in the meantime, which is also done by
x25_disconnect().
Signed-off-by: Martin Schiller <ms@dev.tdt.de>
---
net/x25/af_x25.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
index 6bc2ac8d8146..3b55502b2965 100644
--- a/net/x25/af_x25.c
+++ b/net/x25/af_x25.c
@@ -719,6 +719,11 @@ static int x25_wait_for_connection_establishment(struct sock *sk)
sk->sk_socket->state = SS_UNCONNECTED;
break;
}
+ rc = -ENOTCONN;
+ if (sk->sk_state == TCP_CLOSE) {
+ sk->sk_socket->state = SS_UNCONNECTED;
+ break;
+ }
rc = 0;
if (sk->sk_state != TCP_ESTABLISHED) {
release_sock(sk);
--
2.20.1
next reply other threads:[~2022-08-05 6:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-05 6:18 Martin Schiller [this message]
2022-08-09 4:00 ` [PATCH net] net/x25: fix call timeouts in blocking connects patchwork-bot+netdevbpf
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