[PATCH net-next v7 1/4] net: af_unix: enable custom setsockopt for all socket types

[Jori Koolstra <jkoolstra@xs4all.nl>]

unix_setsockopt() and the SOCK_CUSTOM_SOCKOPT flag were only wired up
for SOCK_STREAM (introduced along with the stream-only SO_INQ).
Consequently custom AF_UNIX options are unreachable on SOCK_DGRAM and
SOCK_SEQPACKET: those setsockopt() calls bypass unix_setsockopt() and
fall through to the generic sock_setsockopt(), failing with
-ENOPROTOOPT.

Set SOCK_CUSTOM_SOCKOPT for every AF_UNIX socket type in unix_create(), and
also for accepted sockets in unix_accept() (reachable for stream and
seqpacket).

This is a prerequisite for making SO_RIGHTS_NOTRUNC settable on all AF_UNIX
socket types.

Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
---
 net/unix/af_unix.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 10ed9421e43a..51cbf920130d 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -950,7 +950,7 @@ static int unix_setsockopt(struct socket *sock, int level, int optname,
 	switch (optname) {
 	case SO_INQ:
 		if (sk->sk_type != SOCK_STREAM)
-			return -EINVAL;
+			return -ENOPROTOOPT;
 
 		if (val > 1 || val < 0)
 			return -EINVAL;
@@ -1006,6 +1006,7 @@ static const struct proto_ops unix_dgram_ops = {
 #endif
 	.listen =	sock_no_listen,
 	.shutdown =	unix_shutdown,
+	.setsockopt =	unix_setsockopt,
 	.sendmsg =	unix_dgram_sendmsg,
 	.read_skb =	unix_read_skb,
 	.recvmsg =	unix_dgram_recvmsg,
@@ -1030,6 +1031,7 @@ static const struct proto_ops unix_seqpacket_ops = {
 #endif
 	.listen =	unix_listen,
 	.shutdown =	unix_shutdown,
+	.setsockopt =	unix_setsockopt,
 	.sendmsg =	unix_seqpacket_sendmsg,
 	.recvmsg =	unix_seqpacket_recvmsg,
 	.mmap =		sock_no_mmap,
@@ -1143,9 +1145,10 @@ static int unix_create(struct net *net, struct socket *sock, int protocol,
 	if (protocol && protocol != PF_UNIX)
 		return -EPROTONOSUPPORT;
 
+	set_bit(SOCK_CUSTOM_SOCKOPT, &sock->flags);
+
 	switch (sock->type) {
 	case SOCK_STREAM:
-		set_bit(SOCK_CUSTOM_SOCKOPT, &sock->flags);
 		sock->ops = &unix_stream_ops;
 		break;
 		/*
@@ -1865,8 +1868,7 @@ static int unix_accept(struct socket *sock, struct socket *newsock,
 	skb_free_datagram(sk, skb);
 	wake_up_interruptible(&unix_sk(sk)->peer_wait);
 
-	if (tsk->sk_type == SOCK_STREAM)
-		set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
+	set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
 
 	/* attach accepted sock to socket */
 	unix_state_lock(tsk);
-- 
2.55.0