SELinux: Add class support to the role_trans structure

If kernel policy version is >= 26, then the binary representation of
the role_trans structure supports specifying the class for the current
subject or the newly created object.

If kernel policy version is < 26, then the class field would be default
to the process class.

Signed-off-by: Harry Ciao <qingtao.cao@windriver.com>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Eric Paris <eparis@redhat.com>

security/selinux/include/security.h

@@ -30,13 +30,14 @@
 #define POLICYDB_VERSION_PERMISSIVE	23
 #define POLICYDB_VERSION_BOUNDARY	24
 #define POLICYDB_VERSION_FILENAME_TRANS	25
+#define POLICYDB_VERSION_ROLETRANS	26
 
 /* Range of policy versions we understand*/
 #define POLICYDB_VERSION_MIN   POLICYDB_VERSION_BASE
 #ifdef CONFIG_SECURITY_SELINUX_POLICYDB_VERSION_MAX
 #define POLICYDB_VERSION_MAX	CONFIG_SECURITY_SELINUX_POLICYDB_VERSION_MAX_VALUE
 #else
-#define POLICYDB_VERSION_MAX	POLICYDB_VERSION_FILENAME_TRANS
+#define POLICYDB_VERSION_MAX	POLICYDB_VERSION_ROLETRANS
 #endif
 
 /* Mask for just the mount related flags */

security/selinux/ss/policydb.c

@@ -128,6 +128,11 @@ static struct policydb_compat_info policydb_compat[] = {
 		.sym_num	= SYM_NUM,
 		.ocon_num	= OCON_NUM,
 	},
+	{
+		.version	= POLICYDB_VERSION_ROLETRANS,
+		.sym_num	= SYM_NUM,
+		.ocon_num	= OCON_NUM,
+	},
 };
 
 static struct policydb_compat_info *policydb_lookup_compat(int version)
@@ -2302,8 +2307,17 @@ int policydb_read(struct policydb *p, void *fp)
 		tr->role = le32_to_cpu(buf[0]);
 		tr->type = le32_to_cpu(buf[1]);
 		tr->new_role = le32_to_cpu(buf[2]);
+		if (p->policyvers >= POLICYDB_VERSION_ROLETRANS) {
+			rc = next_entry(buf, fp, sizeof(u32));
+			if (rc)
+				goto bad;
+			tr->tclass = le32_to_cpu(buf[0]);
+		} else
+			tr->tclass = p->process_class;
+
 		if (!policydb_role_isvalid(p, tr->role) ||
 		    !policydb_type_isvalid(p, tr->type) ||
+		    !policydb_class_isvalid(p, tr->tclass) ||
 		    !policydb_role_isvalid(p, tr->new_role))
 			goto bad;
 		ltr = tr;

security/selinux/ss/policydb.h

@@ -72,7 +72,8 @@ struct role_datum {
 
 struct role_trans {
 	u32 role;		/* current role */
-	u32 type;		/* program executable type */
+	u32 type;		/* program executable type, or new object type */
+	u32 tclass;		/* process class, or new object class */
 	u32 new_role;		/* new role */
 	struct role_trans *next;
 };