diff mbox

[v2,net] sock: ignore SCM_RIGHTS and SCM_CREDENTIALS in __sock_cmsg_send

Message ID 1468270286-7411-1-git-send-email-soheil.kdev@gmail.com
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Soheil Hassas Yeganeh July 11, 2016, 8:51 p.m. UTC 
From: Soheil Hassas Yeganeh <soheil@google.com>

Sergei Trofimovich reported that pulse audio sends SCM_CREDENTIALS
as a control message to TCP. Since __sock_cmsg_send does not
support SCM_RIGHTS and SCM_CREDENTIALS, it returns an error and
hence breaks pulse audio over TCP.

SCM_RIGHTS and SCM_CREDENTIALS are sent on the SOL_SOCKET layer
but they semantically belong to SOL_UNIX. Since all
cmsg-processing functions including sock_cmsg_send ignore control
messages of other layers, it is best to ignore SCM_RIGHTS
and SCM_CREDENTIALS for consistency (and also for fixing pulse
audio over TCP).

Fixes: c14ac9451c34 ("sock: enable timestamping using control messages")
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Reported-by: Sergei Trofimovich <slyfox@gentoo.org>
Tested-by: Sergei Trofimovich <slyfox@gentoo.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
---
 net/core/sock.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

David Miller July 11, 2016, 9:37 p.m. UTC | #1 
From: Soheil Hassas Yeganeh <soheil.kdev@gmail.com>
Date: Mon, 11 Jul 2016 16:51:26 -0400

> From: Soheil Hassas Yeganeh <soheil@google.com>
> 
> Sergei Trofimovich reported that pulse audio sends SCM_CREDENTIALS
> as a control message to TCP. Since __sock_cmsg_send does not
> support SCM_RIGHTS and SCM_CREDENTIALS, it returns an error and
> hence breaks pulse audio over TCP.
> 
> SCM_RIGHTS and SCM_CREDENTIALS are sent on the SOL_SOCKET layer
> but they semantically belong to SOL_UNIX. Since all
> cmsg-processing functions including sock_cmsg_send ignore control
> messages of other layers, it is best to ignore SCM_RIGHTS
> and SCM_CREDENTIALS for consistency (and also for fixing pulse
> audio over TCP).
> 
> Fixes: c14ac9451c34 ("sock: enable timestamping using control messages")
> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
> Reported-by: Sergei Trofimovich <slyfox@gentoo.org>
> Tested-by: Sergei Trofimovich <slyfox@gentoo.org>

Applied and queued up for -stable, thanks.
diff mbox

Patch

diff --git a/net/core/sock.c b/net/core/sock.c
index 08bf97e..b7f1263 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1938,6 +1938,10 @@  int __sock_cmsg_send(struct sock *sk, struct msghdr *msg, struct cmsghdr *cmsg,
 		sockc->tsflags &= ~SOF_TIMESTAMPING_TX_RECORD_MASK;
 		sockc->tsflags |= tsflags;
 		break;
+	/* SCM_RIGHTS and SCM_CREDENTIALS are semantically in SOL_UNIX. */
+	case SCM_RIGHTS:
+	case SCM_CREDENTIALS:
+		break;
 	default:
 		return -EINVAL;
 	}