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authorXin Long <lucien.xin@gmail.com>2024-07-01 19:48:49 +0200
committerDavid S. Miller <davem@davemloft.net>2024-07-03 10:45:39 +0200
commitcda91d5b911a5a168a1c6e6917afda43b0e458c8 (patch)
tree59344614b873294a6a7068fa2f3e2a72add5681b /net
parentnet: dsa: microchip: lan937x: disable VPHY support (diff)
downloadlinux-cda91d5b911a5a168a1c6e6917afda43b0e458c8.tar.xz
linux-cda91d5b911a5a168a1c6e6917afda43b0e458c8.zip
sctp: cancel a blocking accept when shutdown a listen socket
As David Laight noticed, "In a multithreaded program it is reasonable to have a thread blocked in accept(). With TCP a subsequent shutdown(listen_fd, SHUT_RDWR) causes the accept to fail. But nothing happens for SCTP." sctp_disconnect() is eventually called when shutdown a listen socket, but nothing is done in this function. This patch sets RCV_SHUTDOWN flag in sk->sk_shutdown there, and adds the check (sk->sk_shutdown & RCV_SHUTDOWN) to break and return in sctp_accept(). Note that shutdown() is only supported on TCP-style SCTP socket. Reported-by: David Laight <David.Laight@aculab.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sctp/socket.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index c009383369b2..32f76f1298da 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4834,10 +4834,14 @@ int sctp_inet_connect(struct socket *sock, struct sockaddr *uaddr,
return sctp_connect(sock->sk, uaddr, addr_len, flags);
}
-/* FIXME: Write comments. */
+/* Only called when shutdown a listening SCTP socket. */
static int sctp_disconnect(struct sock *sk, int flags)
{
- return -EOPNOTSUPP; /* STUB */
+ if (!sctp_style(sk, TCP))
+ return -EOPNOTSUPP;
+
+ sk->sk_shutdown |= RCV_SHUTDOWN;
+ return 0;
}
/* 4.1.4 accept() - TCP Style Syntax
@@ -4866,7 +4870,8 @@ static struct sock *sctp_accept(struct sock *sk, struct proto_accept_arg *arg)
goto out;
}
- if (!sctp_sstate(sk, LISTENING)) {
+ if (!sctp_sstate(sk, LISTENING) ||
+ (sk->sk_shutdown & RCV_SHUTDOWN)) {
error = -EINVAL;
goto out;
}
@@ -9393,7 +9398,8 @@ static int sctp_wait_for_accept(struct sock *sk, long timeo)
}
err = -EINVAL;
- if (!sctp_sstate(sk, LISTENING))
+ if (!sctp_sstate(sk, LISTENING) ||
+ (sk->sk_shutdown & RCV_SHUTDOWN))
break;
err = 0;