Re: [net-next v5 1/4] net: af_unix: enable custom setsockopt for all socket types

@Kuniyuki,

Could you take a look at this if you have time? Would like to move this
along if we can.

Thanks,
Jori.

Op 19-07-2026 14:31 CEST schreef Jori Koolstra [off-list ref]:

 

quoted

Op 14-07-2026 11:19 CEST schreef Kuniyuki Iwashima [off-list ref]:

 
On Sun, Jul 12, 2026 at 9:29 PM Jori Koolstra [off-list ref] wrote:

quoted

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>
---
 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 f7a9d55eee8a..3d256255085b 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c

@@ -949,7 +949,7 @@ 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;

@@ -1005,6 +1005,7 @@ 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,

@@ -1029,6 +1030,7 @@ 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,

@@ -1142,9 +1144,10 @@ 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);

Please move this to unix_create1(), then we don't need the chunk below.

I don't understand how this helps. The accept() path gets its struct socket from
sock_alloc() not via unix_create() afaict. Also, unix_create1() is called with
sock == NULL on connect(), so now you have to guard against that too.

But maybe I misunderstand you?

I do agree with you other comment, accept() should probably inherit the truncate
behavior from the listen() socket.

Thanks,
Jori.