[PATCH] selinux: add support for range transitions on object classes

Introduces support for policy version 21.  This version of the binary
kernel policy allows for defining range transitions on security classes
other than the process security class.  As always, backwards compatibility
for older formats is retained.  The security class is read in as specified
when using the new format, while the "process" security class is assumed
when using an older policy format.
Signed-off-by: Darrel Goeddel <dgoeddel@trustedcs.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

security/selinux/Kconfig

@@ -145,7 +145,7 @@ config SECURITY_SELINUX_POLICYDB_VERSION_MAX
 config SECURITY_SELINUX_POLICYDB_VERSION_MAX_VALUE
 	int "NSA SELinux maximum supported policy format version value"
 	depends on SECURITY_SELINUX_POLICYDB_VERSION_MAX
-	range 15 20
+	range 15 21
 	default 19
 	help
 	  This option sets the value for the maximum policy format version

security/selinux/include/security.h

@@ -24,13 +24,14 @@
 #define POLICYDB_VERSION_VALIDATETRANS	19
 #define POLICYDB_VERSION_MLS		19
 #define POLICYDB_VERSION_AVTAB		20
+#define POLICYDB_VERSION_RANGETRANS	21
 
 /* 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_AVTAB
+#define POLICYDB_VERSION_MAX	POLICYDB_VERSION_RANGETRANS
 #endif
 
 extern int selinux_enabled;

security/selinux/ss/mls.c

@@ -530,22 +530,21 @@ int mls_compute_sid(struct context *scontext,
 		    u32 specified,
 		    struct context *newcontext)
 {
+	struct range_trans *rtr;
+
 	if (!selinux_mls_enabled)
 		return 0;
 
 	switch (specified) {
 	case AVTAB_TRANSITION:
-		if (tclass == SECCLASS_PROCESS) {
-			struct range_trans *rangetr;
-			/* Look for a range transition rule. */
-			for (rangetr = policydb.range_tr; rangetr;
-			     rangetr = rangetr->next) {
-				if (rangetr->dom == scontext->type &&
-				    rangetr->type == tcontext->type) {
-					/* Set the range from the rule */
-					return mls_range_set(newcontext,
-					                     &rangetr->range);
-				}
+		/* Look for a range transition rule. */
+		for (rtr = policydb.range_tr; rtr; rtr = rtr->next) {
+			if (rtr->source_type == scontext->type &&
+			    rtr->target_type == tcontext->type &&
+			    rtr->target_class == tclass) {
+				/* Set the range from the rule */
+				return mls_range_set(newcontext,
+				                     &rtr->target_range);
 			}
 		}
 		/* Fallthrough */

security/selinux/ss/policydb.c

@@ -96,6 +96,11 @@ static struct policydb_compat_info policydb_compat[] = {
 		.sym_num        = SYM_NUM,
 		.ocon_num       = OCON_NUM,
 	},
+	{
+		.version        = POLICYDB_VERSION_RANGETRANS,
+		.sym_num        = SYM_NUM,
+		.ocon_num       = OCON_NUM,
+	},
 };
 
 static struct policydb_compat_info *policydb_lookup_compat(int version)
@@ -645,15 +650,15 @@ void policydb_destroy(struct policydb *p)
 
 	for (rt = p->range_tr; rt; rt = rt -> next) {
 		if (lrt) {
-			ebitmap_destroy(&lrt->range.level[0].cat);
-			ebitmap_destroy(&lrt->range.level[1].cat);
+			ebitmap_destroy(&lrt->target_range.level[0].cat);
+			ebitmap_destroy(&lrt->target_range.level[1].cat);
 			kfree(lrt);
 		}
 		lrt = rt;
 	}
 	if (lrt) {
-		ebitmap_destroy(&lrt->range.level[0].cat);
-		ebitmap_destroy(&lrt->range.level[1].cat);
+		ebitmap_destroy(&lrt->target_range.level[0].cat);
+		ebitmap_destroy(&lrt->target_range.level[1].cat);
 		kfree(lrt);
 	}
 
@@ -1829,6 +1834,7 @@ int policydb_read(struct policydb *p, void *fp)
 	}
 
 	if (p->policyvers >= POLICYDB_VERSION_MLS) {
+		int new_rangetr = p->policyvers >= POLICYDB_VERSION_RANGETRANS;
 		rc = next_entry(buf, fp, sizeof(u32));
 		if (rc < 0)
 			goto bad;
@@ -1847,9 +1853,16 @@ int policydb_read(struct policydb *p, void *fp)
 			rc = next_entry(buf, fp, (sizeof(u32) * 2));
 			if (rc < 0)
 				goto bad;
-			rt->dom = le32_to_cpu(buf[0]);
-			rt->type = le32_to_cpu(buf[1]);
-			rc = mls_read_range_helper(&rt->range, fp);
+			rt->source_type = le32_to_cpu(buf[0]);
+			rt->target_type = le32_to_cpu(buf[1]);
+			if (new_rangetr) {
+				rc = next_entry(buf, fp, sizeof(u32));
+				if (rc < 0)
+					goto bad;
+				rt->target_class = le32_to_cpu(buf[0]);
+			} else
+				rt->target_class = SECCLASS_PROCESS;
+			rc = mls_read_range_helper(&rt->target_range, fp);
 			if (rc)
 				goto bad;
 			lrt = rt;

security/selinux/ss/policydb.h

@@ -106,9 +106,10 @@ struct cat_datum {
 };
 
 struct range_trans {
-	u32 dom;			/* current process domain */
-	u32 type;			/* program executable type */
-	struct mls_range range;		/* new range */
+	u32 source_type;
+	u32 target_type;
+	u32 target_class;
+	struct mls_range target_range;
 	struct range_trans *next;
 };