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, 45 insertions, 0 deletions

diff --git a/sys/security/mac_biba/mac_biba.c b/sys/security/mac_biba/mac_biba.c
index 778532c..365c397 100644
--- a/sys/security/mac_biba/mac_biba.c
+++ b/sys/security/mac_biba/mac_biba.c
@@ -69,6 +69,7 @@
 #include <net/if_var.h>
 
 #include <netinet/in.h>
+#include <netinet/in_pcb.h>
 #include <netinet/ip_var.h>
 
 #include <vm/vm.h>
@@ -980,6 +981,18 @@ mac_biba_setlabel_vnode_extattr(struct ucred *cred, struct vnode *vp,
  * Labeling event operations: IPC object.
  */
 static void
+mac_biba_create_inpcb_from_socket(struct socket *so, struct label *solabel,
+    struct inpcb *inp, struct label *inplabel)
+{
+	struct mac_biba *source, *dest;
+
+	source = SLOT(solabel);
+	dest = SLOT(inplabel);
+
+	mac_biba_copy_single(source, dest);
+}
+
+static void
 mac_biba_create_mbuf_from_socket(struct socket *so, struct label *socketlabel,
     struct mbuf *m, struct label *mbuflabel)
 {
@@ -1299,6 +1312,18 @@ mac_biba_update_ipq(struct mbuf *fragment, struct label *fragmentlabel,
 	/* NOOP: we only accept matching labels, so no need to update */
 }
 
+static void
+mac_biba_inpcb_sosetlabel(struct socket *so, struct label *solabel,
+    struct inpcb *inp, struct label *inplabel)
+{
+	struct mac_biba *source, *dest;
+
+	source = SLOT(solabel);
+	dest = SLOT(inplabel);
+
+	mac_biba_copy(source, dest);
+}
+
 /*
  * Labeling event operations: processes.
  */
@@ -1493,6 +1518,21 @@ mac_biba_check_ifnet_transmit(struct ifnet *ifnet, struct label *ifnetlabel,
 }
 
 static int
+mac_biba_check_inpcb_deliver(struct inpcb *inp, struct label *inplabel,
+    struct mbuf *m, struct label *mlabel)
+{
+	struct mac_biba *p, *i;
+
+	if (!mac_biba_enabled)
+		return (0);
+
+	p = SLOT(mlabel);
+	i = SLOT(inplabel);
+
+	return (mac_biba_equal_single(p, i) ? 0 : EACCES);
+}
+
+static int
 mac_biba_check_kld_load(struct ucred *cred, struct vnode *vp,
     struct label *label)
 {
@@ -2606,6 +2646,7 @@ static struct mac_policy_ops mac_biba_ops =
 	.mpo_init_cred_label = mac_biba_init_label,
 	.mpo_init_devfsdirent_label = mac_biba_init_label,
 	.mpo_init_ifnet_label = mac_biba_init_label,
+	.mpo_init_inpcb_label = mac_biba_init_label_waitcheck,
 	.mpo_init_ipq_label = mac_biba_init_label_waitcheck,
 	.mpo_init_mbuf_label = mac_biba_init_label_waitcheck,
 	.mpo_init_mount_label = mac_biba_init_label,
@@ -2618,6 +2659,7 @@ static struct mac_policy_ops mac_biba_ops =
 	.mpo_destroy_cred_label = mac_biba_destroy_label,
 	.mpo_destroy_devfsdirent_label = mac_biba_destroy_label,
 	.mpo_destroy_ifnet_label = mac_biba_destroy_label,
+	.mpo_destroy_inpcb_label = mac_biba_destroy_label,
 	.mpo_destroy_ipq_label = mac_biba_destroy_label,
 	.mpo_destroy_mbuf_label = mac_biba_destroy_label,
 	.mpo_destroy_mount_label = mac_biba_destroy_label,
@@ -2665,6 +2707,7 @@ static struct mac_policy_ops mac_biba_ops =
 	.mpo_create_datagram_from_ipq = mac_biba_create_datagram_from_ipq,
 	.mpo_create_fragment = mac_biba_create_fragment,
 	.mpo_create_ifnet = mac_biba_create_ifnet,
+	.mpo_create_inpcb_from_socket = mac_biba_create_inpcb_from_socket,
 	.mpo_create_ipq = mac_biba_create_ipq,
 	.mpo_create_mbuf_from_mbuf = mac_biba_create_mbuf_from_mbuf,
 	.mpo_create_mbuf_linklayer = mac_biba_create_mbuf_linklayer,
@@ -2675,6 +2718,7 @@ static struct mac_policy_ops mac_biba_ops =
 	.mpo_fragment_match = mac_biba_fragment_match,
 	.mpo_relabel_ifnet = mac_biba_relabel_ifnet,
 	.mpo_update_ipq = mac_biba_update_ipq,
+	.mpo_inpcb_sosetlabel = mac_biba_inpcb_sosetlabel,
 	.mpo_create_cred = mac_biba_create_cred,
 	.mpo_create_proc0 = mac_biba_create_proc0,
 	.mpo_create_proc1 = mac_biba_create_proc1,
@@ -2684,6 +2728,7 @@ static struct mac_policy_ops mac_biba_ops =
 	.mpo_check_cred_visible = mac_biba_check_cred_visible,
 	.mpo_check_ifnet_relabel = mac_biba_check_ifnet_relabel,
 	.mpo_check_ifnet_transmit = mac_biba_check_ifnet_transmit,
+	.mpo_check_inpcb_deliver = mac_biba_check_inpcb_deliver,
 	.mpo_check_kld_load = mac_biba_check_kld_load,
 	.mpo_check_kld_unload = mac_biba_check_kld_unload,
 	.mpo_check_mount_stat = mac_biba_check_mount_stat,