selinux: log policy capability state when a policy is loaded

Log the state of SELinux policy capabilities when a policy is loaded.
For each policy capability known to the kernel, log the policy capability
name and the value set in the policy.  For policy capabilities that are
set in the loaded policy but unknown to the kernel, log the policy
capability index, since this is the only information presently available
in the policy.

Sample output with a policy created with a new capability defined
that is not known to the kernel:
SELinux:  policy capability network_peer_controls=1
SELinux:  policy capability open_perms=1
SELinux:  policy capability extended_socket_class=1
SELinux:  policy capability always_check_network=0
SELinux:  policy capability cgroup_seclabel=0
SELinux:  unknown policy capability 5

Resolves: https://github.com/SELinuxProject/selinux-kernel/issues/32

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/include/security.h

@@ -76,6 +76,8 @@ enum {
 };
 #define POLICYDB_CAPABILITY_MAX (__POLICYDB_CAPABILITY_MAX - 1)
 
+extern char *selinux_policycap_names[__POLICYDB_CAPABILITY_MAX];
+
 extern int selinux_policycap_netpeer;
 extern int selinux_policycap_openperm;
 extern int selinux_policycap_extsockclass;

security/selinux/selinuxfs.c

@@ -41,15 +41,6 @@
 #include "objsec.h"
 #include "conditional.h"
 
-/* Policy capability filenames */
-static char *policycap_names[] = {
-	"network_peer_controls",
-	"open_perms",
-	"extended_socket_class",
-	"always_check_network",
-	"cgroup_seclabel"
-};
-
 unsigned int selinux_checkreqprot = CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE;
 
 static int __init checkreqprot_setup(char *str)
@@ -1750,9 +1741,9 @@ static int sel_make_policycap(void)
 	sel_remove_entries(policycap_dir);
 
 	for (iter = 0; iter <= POLICYDB_CAPABILITY_MAX; iter++) {
-		if (iter < ARRAY_SIZE(policycap_names))
+		if (iter < ARRAY_SIZE(selinux_policycap_names))
 			dentry = d_alloc_name(policycap_dir,
-					      policycap_names[iter]);
+					      selinux_policycap_names[iter]);
 		else
 			dentry = d_alloc_name(policycap_dir, "unknown");
 

security/selinux/ss/services.c

@@ -70,6 +70,15 @@
 #include "ebitmap.h"
 #include "audit.h"
 
+/* Policy capability names */
+char *selinux_policycap_names[__POLICYDB_CAPABILITY_MAX] = {
+	"network_peer_controls",
+	"open_perms",
+	"extended_socket_class",
+	"always_check_network",
+	"cgroup_seclabel"
+};
+
 int selinux_policycap_netpeer;
 int selinux_policycap_openperm;
 int selinux_policycap_extsockclass;
@@ -1986,6 +1995,9 @@ bad:
 
 static void security_load_policycaps(void)
 {
+	unsigned int i;
+	struct ebitmap_node *node;
+
 	selinux_policycap_netpeer = ebitmap_get_bit(&policydb.policycaps,
 						  POLICYDB_CAPABILITY_NETPEER);
 	selinux_policycap_openperm = ebitmap_get_bit(&policydb.policycaps,
@@ -1997,6 +2009,17 @@ static void security_load_policycaps(void)
 	selinux_policycap_cgroupseclabel =
 		ebitmap_get_bit(&policydb.policycaps,
 				POLICYDB_CAPABILITY_CGROUPSECLABEL);
+
+	for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
+		pr_info("SELinux:  policy capability %s=%d\n",
+			selinux_policycap_names[i],
+			ebitmap_get_bit(&policydb.policycaps, i));
+
+	ebitmap_for_each_positive_bit(&policydb.policycaps, node, i) {
+		if (i >= ARRAY_SIZE(selinux_policycap_names))
+			pr_info("SELinux:  unknown policy capability %u\n",
+				i);
+	}
 }
 
 static int security_preserve_bools(struct policydb *p);