Introduce a MAC label reference in 'struct inpcb', which caches

the   MAC label referenced from 'struct socket' in the IPv4 and
IPv6-based protocols.  This permits MAC labels to be checked during
network delivery operations without dereferencing inp->inp_socket
to get to so->so_label, which will eventually avoid our having to
grab the socket lock during delivery at the network layer.

This change introduces 'struct inpcb' as a labeled object to the
MAC Framework, along with the normal circus of entry points:
initialization, creation from socket, destruction, as well as a
delivery access control check.

For most policies, the inpcb label will simply be a cache of the
socket label, so a new protocol switch method is introduced,
pr_sosetlabel() to notify protocols that the socket layer label
has been updated so that the cache can be updated while holding
appropriate locks.  Most protocols implement this using
pru_sosetlabel_null(), but IPv4/IPv6 protocols using inpcbs use
the the worker function in_pcbsosetlabel(), which calls into the
MAC Framework to perform a cache update.

Biba, LOMAC, and MLS implement these entry points, as do the stub
policy, and test policy.

Reviewed by:	sam, bms
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories

1 files changed, 2 insertions, 2 deletions

diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 4df4a99d0f10..a24713843420 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -683,11 +683,11 @@ findpcb:
 	else
 		tiwin = th->th_win;
 
-	so = inp->inp_socket;
 #ifdef MAC
-	if (mac_check_socket_deliver(so, m))
+	if (mac_check_inpcb_deliver(inp, m))
 		goto drop;
 #endif
+	so = inp->inp_socket;
 #ifdef TCPDEBUG
 	if (so->so_options & SO_DEBUG) {
 		ostate = tp->t_state;