kernel support for new range_transition statements

This patch 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 <[email protected]>

 include/security.h |    3 ++-
 ss/mls.c           |   21 ++++++++++-----------
 ss/policydb.c      |   27 ++++++++++++++++++++-------
 ss/policydb.h      |    7 ++++---
 4 files changed, 36 insertions(+), 22 deletions(-)

security/selinux/include/security.h +2 -1

index 063af47..389078e 100644
@@ -24,10 +24,11 @@ #define POLICYDB_VERSION_NLCLASS	18
 #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
-#define POLICYDB_VERSION_MAX   POLICYDB_VERSION_AVTAB
+#define POLICYDB_VERSION_MAX   POLICYDB_VERSION_RANGETRANS
 
 extern int selinux_enabled;
 extern int selinux_mls_enabled;

security/selinux/ss/mls.c +10 -11

index 7bc5b64..df2540c 100644
@@ -543,22 +543,21 @@ int mls_compute_sid(struct context *scon
 		    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 +20 -7

index f03960e..b188953 100644
@@ -96,6 +96,11 @@ static struct policydb_compat_info polic
 		.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, vo
 	}
 
 	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, vo
 			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 +4 -3

index b134071..8319d5f 100644
@@ -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;
 };
 

Quoted 8 lines · Darrel Goeddel

This patch 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 <[email protected]>

Acked-by Stephen Smalley <[email protected]>