[PATCH v1 net-next] Revert "af_unix: Call scm_recv() only after scm_set_cred()."

[Kuniyuki Iwashima <kuniyu@amazon.com>]

This reverts commit 3f5f118bb657f94641ea383c7c1b8c09a5d46ea2.

Konrad reported that desktop environment below cannot be reached after
commit 3f5f118bb657 ("af_unix: Call scm_recv() only after scm_set_cred().")

  - postmarketOS (Alpine Linux w/ musl 1.2.4)
  - busybox 1.36.1
  - GNOME 44.1
  - networkmanager 1.42.6
  - openrc 0.47

Regarding to the warning of SO_PASSPIDFD, I'll post another patch to
suppress it by skipping SCM_PIDFD if scm->pid == NULL in scm_pidfd_recv().

Reported-by: Konrad Dybcio <konradybcio@kernel.org>
Link: https://lore.kernel.org/netdev/8c7f9abd-4f84-7296-2788-1e130d6304a0@kernel.org/
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
To maintainers

Sorry for bothering, but can this make it to the v6.5 train to
avoid regression reports ?
---
 net/unix/af_unix.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index f2f234f0b92c..3953daa2e1d0 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2807,7 +2807,7 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state,
 	} while (size);
 
 	mutex_unlock(&u->iolock);
-	if (state->msg && check_creds)
+	if (state->msg)
 		scm_recv(sock, state->msg, &scm, flags);
 	else
 		scm_destroy(&scm);
-- 
2.30.2