RE: [PATCH] tipc: fix shutdown() of connection oriented socket

["Xue, Ying" <Ying.Xue@windriver.com>]

-----Original Message-----
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> 
Sent: Saturday, September 5, 2020 2:15 PM
To: Jon Maloy <jmaloy@redhat.com>; Xue, Ying <Ying.Xue@windriver.com>; Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@gmail.com>
Cc: David S. Miller <davem@davemloft.net>; Jakub Kicinski <kuba@kernel.org>; netdev@vger.kernel.org; tipc-discussion@lists.sourceforge.net; Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Subject: [PATCH] tipc: fix shutdown() of connection oriented socket

I confirmed that the problem fixed by commit 2a63866c8b51a3f7 ("tipc: fix
shutdown() of connectionless socket") also applies to stream socket.

----------
#include <sys/socket.h>
#include <unistd.h>
#include <sys/wait.h>

int main(int argc, char *argv[])
{
        int fds[2] = { -1, -1 };
        socketpair(PF_TIPC, SOCK_STREAM /* or SOCK_DGRAM */, 0, fds);
        if (fork() == 0)
                _exit(read(fds[0], NULL, 1));
        shutdown(fds[0], SHUT_RDWR); /* This must make read() return. */
        wait(NULL); /* To be woken up by _exit(). */
        return 0;
}
----------

Since shutdown(SHUT_RDWR) should affect all processes sharing that socket, unconditionally setting sk->sk_shutdown to SHUTDOWN_MASK will be the right behavior.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

Acked-by: Ying Xue <ying.xue@windriver.com>

---
 net/tipc/socket.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/net/tipc/socket.c b/net/tipc/socket.c index ebd280e767bd..11b27ddc75ba 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -2771,10 +2771,7 @@ static int tipc_shutdown(struct socket *sock, int how)
 
 	trace_tipc_sk_shutdown(sk, NULL, TIPC_DUMP_ALL, " ");
 	__tipc_shutdown(sock, TIPC_CONN_SHUTDOWN);
-	if (tipc_sk_type_connectionless(sk))
-		sk->sk_shutdown = SHUTDOWN_MASK;
-	else
-		sk->sk_shutdown = SEND_SHUTDOWN;
+	sk->sk_shutdown = SHUTDOWN_MASK;
 
 	if (sk->sk_state == TIPC_DISCONNECTING) {
 		/* Discard any unreceived messages */
--
2.18.4