SELinux: Add network port SID cache

Much like we added a network node cache, this patch adds a network port
cache. The design is taken almost completely from the network node cache
which in turn was taken from the network interface cache. The basic idea is
to cache entries in a hash table based on protocol/port information. The
hash function only takes the port number into account since the number of
different protocols in use at any one time is expected to be relatively
small.

Signed-off-by: Paul Moore <[e-mail]>
Acked-by: Stephen Smalley <[e-mail]>
Signed-off-by: James Morris <[e-mail]>

security/selinux/Makefile

···
 	     nlmsgtab.o \
 	     netif.o \
 	     netnode.o \
+	     netport.o \
 	     exports.o
 
 selinux-$(CONFIG_SECURITY_NETWORK_XFRM) += xfrm.o

security/selinux/hooks.c

···
 #include "objsec.h"
 #include "netif.h"
 #include "netnode.h"
+#include "netport.h"
 #include "xfrm.h"
 #include "netlabel.h"
 
···
 			inet_get_local_port_range(&low, &high);
 
 			if (snum < max(PROT_SOCK, low) || snum > high) {
-				err = security_port_sid(sk->sk_family,
-							sk->sk_type,
-							sk->sk_protocol, snum,
-							&sid);
+				err = sel_netport_sid(sk->sk_protocol,
+						      snum, &sid);
 				if (err)
 					goto out;
 				AVC_AUDIT_DATA_INIT(&ad,NET);
···
 			snum = ntohs(addr6->sin6_port);
 		}
 
-		err = security_port_sid(sk->sk_family, sk->sk_type,
-					sk->sk_protocol, snum, &sid);
+		err = sel_netport_sid(sk->sk_protocol, snum, &sid);
 		if (err)
 			goto out;
 
···
 
 	if (!recv_perm)
 		return 0;
-	err = security_port_sid(sk->sk_family, sk->sk_type,
-				sk->sk_protocol, ntohs(ad->u.net.sport),
-				&port_sid);
+	err = sel_netport_sid(sk->sk_protocol,
+			      ntohs(ad->u.net.sport), &port_sid);
 	if (unlikely(err)) {
 		printk(KERN_WARNING
 		       "SELinux: failure in"
···
 	if (send_perm != 0)
 		return 0;
 
-	err = security_port_sid(sk->sk_family, sk->sk_type,
-				sk->sk_protocol, ntohs(ad->u.net.dport),
-				&port_sid);
+	err = sel_netport_sid(sk->sk_protocol,
+			      ntohs(ad->u.net.dport), &port_sid);
 	if (unlikely(err)) {
 		printk(KERN_WARNING
 		       "SELinux: failure in"

security/selinux/include/objsec.h

···
 	u16 family;			/* address family */
 };
 
+struct netport_security_struct {
+	u32 sid;			/* SID for this node */
+	u16 port;			/* port number */
+	u8 protocol;			/* transport protocol */
+};
+
 struct sk_security_struct {
 	u32 sid;			/* SID of this object */
 	u32 peer_sid;			/* SID of peer */

security/selinux/include/security.h

···
 int security_get_user_sids(u32 callsid, char *username,
 			   u32 **sids, u32 *nel);
 
-int security_port_sid(u16 domain, u16 type, u8 protocol, u16 port,
-	u32 *out_sid);
+int security_port_sid(u8 protocol, u16 port, u32 *out_sid);
 
 int security_netif_sid(char *name, u32 *if_sid);
 

security/selinux/ss/services.c

···
 
 /**
  * security_port_sid - Obtain the SID for a port.
- * @domain: communication domain aka address family
- * @type: socket type
  * @protocol: protocol number
  * @port: port number
  * @out_sid: security identifier
  */
-int security_port_sid(u16 domain,
-		      u16 type,
-		      u8 protocol,
-		      u16 port,
-		      u32 *out_sid)
+int security_port_sid(u8 protocol, u16 port, u32 *out_sid)
 {
 	struct ocontext *c;
 	int rc = 0;