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authorSoheil Hassas Yeganeh <soheil@google.com>2016-07-11 16:51:26 -0400
committerDavid S. Miller <davem@davemloft.net>2016-07-11 14:32:44 -0700
commit779f1edec664a7b32b71f7b4702e085a08d60592 (patch)
treece41ff39e7f4ae46de19e66ed759cd9ae426e595 /net/core/sock.c
parent80610229ef7b26615dbb6cb6e873709a60bacc9f (diff)
downloadlinux-779f1edec664a7b32b71f7b4702e085a08d60592.tar.gz
sock: ignore SCM_RIGHTS and SCM_CREDENTIALS in __sock_cmsg_send
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/sock.c')
-rw-r--r--net/core/sock.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index 08bf97eceeb3..b7f12639c26a 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;
 	}