net: net_cls: fd passed in SCM_RIGHTS datagram not set correctly

Commit 6a328d8c6f03501657ad580f6f98bf9a42583ff7 changed the update
logic for the socket but it does not update the SCM_RIGHTS update
as well. This patch is based on the net_prio fix commit

48a87cc26c13b68f6cce4e9d769fcb17a6b3e4b8

    net: netprio: fd passed in SCM_RIGHTS datagram not set correctly

    A socket fd passed in a SCM_RIGHTS datagram was not getting
    updated with the new tasks cgrp prioidx. This leaves IO on
    the socket tagged with the old tasks priority.

    To fix this add a check in the scm recvmsg path to update the
    sock cgrp prioidx with the new tasks value.

Let's apply the same fix for net_cls.

Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Reported-by: Li Zefan <lizefan@huawei.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: netdev@vger.kernel.org
Cc: cgroups@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/scm.c

@@ -35,6 +35,7 @@
 #include <net/sock.h>
 #include <net/compat.h>
 #include <net/scm.h>
+#include <net/cls_cgroup.h>
 
 
 /*
@@ -302,8 +303,10 @@ void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
 		}
 		/* Bump the usage count and install the file. */
 		sock = sock_from_file(fp[i], &err);
-		if (sock)
+		if (sock) {
 			sock_update_netprioidx(sock->sk, current);
+			sock_update_classid(sock->sk, current);
+		}
 		fd_install(new_fd, get_file(fp[i]));
 	}