Merge branch 'next' into for-linus

7 files changed, 266 insertions, 213 deletions

diff --git a/security/selinux/ss/context.h b/security/selinux/ss/context.h
index d9dd7a2f6a8a..45e8fb0515f8 100644
--- a/security/selinux/ss/context.h
+++ b/security/selinux/ss/context.h
@@ -41,9 +41,6 @@ static inline int mls_context_cpy(struct context *dst, struct context *src)
 {
 	int rc;
 
-	if (!selinux_mls_enabled)
-		return 0;
-
 	dst->range.level[0].sens = src->range.level[0].sens;
 	rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat);
 	if (rc)
@@ -64,9 +61,6 @@ static inline int mls_context_cpy_low(struct context *dst, struct context *src)
 {
 	int rc;
 
-	if (!selinux_mls_enabled)
-		return 0;
-
 	dst->range.level[0].sens = src->range.level[0].sens;
 	rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat);
 	if (rc)
@@ -82,9 +76,6 @@ out:
 
 static inline int mls_context_cmp(struct context *c1, struct context *c2)
 {
-	if (!selinux_mls_enabled)
-		return 1;
-
 	return ((c1->range.level[0].sens == c2->range.level[0].sens) &&
 		ebitmap_cmp(&c1->range.level[0].cat, &c2->range.level[0].cat) &&
 		(c1->range.level[1].sens == c2->range.level[1].sens) &&
@@ -93,9 +84,6 @@ static inline int mls_context_cmp(struct context *c1, struct context *c2)
 
 static inline void mls_context_destroy(struct context *c)
 {
-	if (!selinux_mls_enabled)
-		return;
-
 	ebitmap_destroy(&c->range.level[0].cat);
 	ebitmap_destroy(&c->range.level[1].cat);
 	mls_context_init(c);
diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c
index 3f2b2706b5bb..372b773f8210 100644
--- a/security/selinux/ss/mls.c
+++ b/security/selinux/ss/mls.c
@@ -39,7 +39,7 @@ int mls_compute_context_len(struct context *context)
 	struct ebitmap *e;
 	struct ebitmap_node *node;
 
-	if (!selinux_mls_enabled)
+	if (!policydb.mls_enabled)
 		return 0;
 
 	len = 1; /* for the beginning ":" */
@@ -93,7 +93,7 @@ void mls_sid_to_context(struct context *context,
 	struct ebitmap *e;
 	struct ebitmap_node *node;
 
-	if (!selinux_mls_enabled)
+	if (!policydb.mls_enabled)
 		return;
 
 	scontextp = *scontext;
@@ -200,7 +200,7 @@ int mls_context_isvalid(struct policydb *p, struct context *c)
 {
 	struct user_datum *usrdatum;
 
-	if (!selinux_mls_enabled)
+	if (!p->mls_enabled)
 		return 1;
 
 	if (!mls_range_isvalid(p, &c->range))
@@ -253,7 +253,7 @@ int mls_context_to_sid(struct policydb *pol,
 	struct cat_datum *catdatum, *rngdatum;
 	int l, rc = -EINVAL;
 
-	if (!selinux_mls_enabled) {
+	if (!pol->mls_enabled) {
 		if (def_sid != SECSID_NULL && oldc)
 			*scontext += strlen(*scontext)+1;
 		return 0;
@@ -387,7 +387,7 @@ int mls_from_string(char *str, struct context *context, gfp_t gfp_mask)
 	char *tmpstr, *freestr;
 	int rc;
 
-	if (!selinux_mls_enabled)
+	if (!policydb.mls_enabled)
 		return -EINVAL;
 
 	/* we need freestr because mls_context_to_sid will change
@@ -407,7 +407,7 @@ int mls_from_string(char *str, struct context *context, gfp_t gfp_mask)
 /*
  * Copies the MLS range `range' into `context'.
  */
-static inline int mls_range_set(struct context *context,
+int mls_range_set(struct context *context,
 				struct mls_range *range)
 {
 	int l, rc = 0;
@@ -427,7 +427,7 @@ static inline int mls_range_set(struct context *context,
 int mls_setup_user_range(struct context *fromcon, struct user_datum *user,
 			 struct context *usercon)
 {
-	if (selinux_mls_enabled) {
+	if (policydb.mls_enabled) {
 		struct mls_level *fromcon_sen = &(fromcon->range.level[0]);
 		struct mls_level *fromcon_clr = &(fromcon->range.level[1]);
 		struct mls_level *user_low = &(user->range.level[0]);
@@ -477,7 +477,7 @@ int mls_convert_context(struct policydb *oldp,
 	struct ebitmap_node *node;
 	int l, i;
 
-	if (!selinux_mls_enabled)
+	if (!policydb.mls_enabled)
 		return 0;
 
 	for (l = 0; l < 2; l++) {
@@ -513,23 +513,21 @@ int mls_compute_sid(struct context *scontext,
 		    u32 specified,
 		    struct context *newcontext)
 {
-	struct range_trans *rtr;
+	struct range_trans rtr;
+	struct mls_range *r;
 
-	if (!selinux_mls_enabled)
+	if (!policydb.mls_enabled)
 		return 0;
 
 	switch (specified) {
 	case AVTAB_TRANSITION:
 		/* 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);
-			}
-		}
+		rtr.source_type = scontext->type;
+		rtr.target_type = tcontext->type;
+		rtr.target_class = tclass;
+		r = hashtab_search(policydb.range_tr, &rtr);
+		if (r)
+			return mls_range_set(newcontext, r);
 		/* Fallthrough */
 	case AVTAB_CHANGE:
 		if (tclass == policydb.process_class)
@@ -541,8 +539,8 @@ int mls_compute_sid(struct context *scontext,
 	case AVTAB_MEMBER:
 		/* Use the process effective MLS attributes. */
 		return mls_context_cpy_low(newcontext, scontext);
-	default:
-		return -EINVAL;
+
+	/* fall through */
 	}
 	return -EINVAL;
 }
@@ -561,7 +559,7 @@ int mls_compute_sid(struct context *scontext,
 void mls_export_netlbl_lvl(struct context *context,
 			   struct netlbl_lsm_secattr *secattr)
 {
-	if (!selinux_mls_enabled)
+	if (!policydb.mls_enabled)
 		return;
 
 	secattr->attr.mls.lvl = context->range.level[0].sens - 1;
@@ -581,7 +579,7 @@ void mls_export_netlbl_lvl(struct context *context,
 void mls_import_netlbl_lvl(struct context *context,
 			   struct netlbl_lsm_secattr *secattr)
 {
-	if (!selinux_mls_enabled)
+	if (!policydb.mls_enabled)
 		return;
 
 	context->range.level[0].sens = secattr->attr.mls.lvl + 1;
@@ -603,7 +601,7 @@ int mls_export_netlbl_cat(struct context *context,
 {
 	int rc;
 
-	if (!selinux_mls_enabled)
+	if (!policydb.mls_enabled)
 		return 0;
 
 	rc = ebitmap_netlbl_export(&context->range.level[0].cat,
@@ -631,7 +629,7 @@ int mls_import_netlbl_cat(struct context *context,
 {
 	int rc;
 
-	if (!selinux_mls_enabled)
+	if (!policydb.mls_enabled)
 		return 0;
 
 	rc = ebitmap_netlbl_import(&context->range.level[0].cat,
diff --git a/security/selinux/ss/mls.h b/security/selinux/ss/mls.h
index 1276715aaa8b..cd9152632e54 100644
--- a/security/selinux/ss/mls.h
+++ b/security/selinux/ss/mls.h
@@ -39,6 +39,8 @@ int mls_context_to_sid(struct policydb *p,
 
 int mls_from_string(char *str, struct context *context, gfp_t gfp_mask);
 
+int mls_range_set(struct context *context, struct mls_range *range);
+
 int mls_convert_context(struct policydb *oldp,
 			struct policydb *newp,
 			struct context *context);
diff --git a/security/selinux/ss/mls_types.h b/security/selinux/ss/mls_types.h
index b6e943a21061..03bed52a8052 100644
--- a/security/selinux/ss/mls_types.h
+++ b/security/selinux/ss/mls_types.h
@@ -15,6 +15,7 @@
 #define _SS_MLS_TYPES_H_
 
 #include "security.h"
+#include "ebitmap.h"
 
 struct mls_level {
 	u32 sens;		/* sensitivity */
@@ -27,18 +28,12 @@ struct mls_range {
 
 static inline int mls_level_eq(struct mls_level *l1, struct mls_level *l2)
 {
-	if (!selinux_mls_enabled)
-		return 1;
-
 	return ((l1->sens == l2->sens) &&
 		ebitmap_cmp(&l1->cat, &l2->cat));
 }
 
 static inline int mls_level_dom(struct mls_level *l1, struct mls_level *l2)
 {
-	if (!selinux_mls_enabled)
-		return 1;
-
 	return ((l1->sens >= l2->sens) &&
 		ebitmap_contains(&l1->cat, &l2->cat));
 }
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index f03667213ea8..23c6e53c102c 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -52,8 +52,6 @@ static char *symtab_name[SYM_NUM] = {
 };
 #endif
 
-int selinux_mls_enabled;
-
 static unsigned int symtab_sizes[SYM_NUM] = {
 	2,
 	32,
@@ -177,6 +175,21 @@ out_free_role:
 	goto out;
 }
 
+static u32 rangetr_hash(struct hashtab *h, const void *k)
+{
+	const struct range_trans *key = k;
+	return (key->source_type + (key->target_type << 3) +
+		(key->target_class << 5)) & (h->size - 1);
+}
+
+static int rangetr_cmp(struct hashtab *h, const void *k1, const void *k2)
+{
+	const struct range_trans *key1 = k1, *key2 = k2;
+	return (key1->source_type != key2->source_type ||
+		key1->target_type != key2->target_type ||
+		key1->target_class != key2->target_class);
+}
+
 /*
  * Initialize a policy database structure.
  */
@@ -204,6 +217,10 @@ static int policydb_init(struct policydb *p)
 	if (rc)
 		goto out_free_symtab;
 
+	p->range_tr = hashtab_create(rangetr_hash, rangetr_cmp, 256);
+	if (!p->range_tr)
+		goto out_free_symtab;
+
 	ebitmap_init(&p->policycaps);
 	ebitmap_init(&p->permissive_map);
 
@@ -408,6 +425,20 @@ static void symtab_hash_eval(struct symtab *s)
 		       info.slots_used, h->size, info.max_chain_len);
 	}
 }
+
+static void rangetr_hash_eval(struct hashtab *h)
+{
+	struct hashtab_info info;
+
+	hashtab_stat(h, &info);
+	printk(KERN_DEBUG "SELinux: rangetr:  %d entries and %d/%d buckets used, "
+	       "longest chain length %d\n", h->nel,
+	       info.slots_used, h->size, info.max_chain_len);
+}
+#else
+static inline void rangetr_hash_eval(struct hashtab *h)
+{
+}
 #endif
 
 /*
@@ -422,7 +453,7 @@ static int policydb_index_others(struct policydb *p)
 
 	printk(KERN_DEBUG "SELinux:  %d users, %d roles, %d types, %d bools",
 	       p->p_users.nprim, p->p_roles.nprim, p->p_types.nprim, p->p_bools.nprim);
-	if (selinux_mls_enabled)
+	if (p->mls_enabled)
 		printk(", %d sens, %d cats", p->p_levels.nprim,
 		       p->p_cats.nprim);
 	printk("\n");
@@ -612,6 +643,17 @@ static int (*destroy_f[SYM_NUM]) (void *key, void *datum, void *datap) =
 	cat_destroy,
 };
 
+static int range_tr_destroy(void *key, void *datum, void *p)
+{
+	struct mls_range *rt = datum;
+	kfree(key);
+	ebitmap_destroy(&rt->level[0].cat);
+	ebitmap_destroy(&rt->level[1].cat);
+	kfree(datum);
+	cond_resched();
+	return 0;
+}
+
 static void ocontext_destroy(struct ocontext *c, int i)
 {
 	context_destroy(&c->context[0]);
@@ -632,7 +674,6 @@ void policydb_destroy(struct policydb *p)
 	int i;
 	struct role_allow *ra, *lra = NULL;
 	struct role_trans *tr, *ltr = NULL;
-	struct range_trans *rt, *lrt = NULL;
 
 	for (i = 0; i < SYM_NUM; i++) {
 		cond_resched();
@@ -693,20 +734,8 @@ void policydb_destroy(struct policydb *p)
 	}
 	kfree(lra);
 
-	for (rt = p->range_tr; rt; rt = rt->next) {
-		cond_resched();
-		if (lrt) {
-			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->target_range.level[0].cat);
-		ebitmap_destroy(&lrt->target_range.level[1].cat);
-		kfree(lrt);
-	}
+	hashtab_map(p->range_tr, range_tr_destroy, NULL);
+	hashtab_destroy(p->range_tr);
 
 	if (p->type_attr_map) {
 		for (i = 0; i < p->p_types.nprim; i++)
@@ -1686,12 +1715,11 @@ int policydb_read(struct policydb *p, void *fp)
 	int i, j, rc;
 	__le32 buf[4];
 	u32 nodebuf[8];
-	u32 len, len2, config, nprim, nel, nel2;
+	u32 len, len2, nprim, nel, nel2;
 	char *policydb_str;
 	struct policydb_compat_info *info;
-	struct range_trans *rt, *lrt;
-
-	config = 0;
+	struct range_trans *rt;
+	struct mls_range *r;
 
 	rc = policydb_init(p);
 	if (rc)
@@ -1740,7 +1768,7 @@ int policydb_read(struct policydb *p, void *fp)
 	kfree(policydb_str);
 	policydb_str = NULL;
 
-	/* Read the version, config, and table sizes. */
+	/* Read the version and table sizes. */
 	rc = next_entry(buf, fp, sizeof(u32)*4);
 	if (rc < 0)
 		goto bad;
@@ -1755,13 +1783,7 @@ int policydb_read(struct policydb *p, void *fp)
 	}
 
 	if ((le32_to_cpu(buf[1]) & POLICYDB_CONFIG_MLS)) {
-		if (ss_initialized && !selinux_mls_enabled) {
-			printk(KERN_ERR "SELinux: Cannot switch between non-MLS"
-				" and MLS policies\n");
-			goto bad;
-		}
-		selinux_mls_enabled = 1;
-		config |= POLICYDB_CONFIG_MLS;
+		p->mls_enabled = 1;
 
 		if (p->policyvers < POLICYDB_VERSION_MLS) {
 			printk(KERN_ERR "SELinux: security policydb version %d "
@@ -1769,12 +1791,6 @@ int policydb_read(struct policydb *p, void *fp)
 				p->policyvers);
 			goto bad;
 		}
-	} else {
-		if (ss_initialized && selinux_mls_enabled) {
-			printk(KERN_ERR "SELinux: Cannot switch between MLS and"
-				" non-MLS policies\n");
-			goto bad;
-		}
 	}
 	p->reject_unknown = !!(le32_to_cpu(buf[1]) & REJECT_UNKNOWN);
 	p->allow_unknown = !!(le32_to_cpu(buf[1]) & ALLOW_UNKNOWN);
@@ -2122,44 +2138,61 @@ int policydb_read(struct policydb *p, void *fp)
 		if (rc < 0)
 			goto bad;
 		nel = le32_to_cpu(buf[0]);
-		lrt = NULL;
 		for (i = 0; i < nel; i++) {
 			rt = kzalloc(sizeof(*rt), GFP_KERNEL);
 			if (!rt) {
 				rc = -ENOMEM;
 				goto bad;
 			}
-			if (lrt)
-				lrt->next = rt;
-			else
-				p->range_tr = rt;
 			rc = next_entry(buf, fp, (sizeof(u32) * 2));
-			if (rc < 0)
+			if (rc < 0) {
+				kfree(rt);
 				goto bad;
+			}
 			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)
+				if (rc < 0) {
+					kfree(rt);
 					goto bad;
+				}
 				rt->target_class = le32_to_cpu(buf[0]);
 			} else
 				rt->target_class = p->process_class;
 			if (!policydb_type_isvalid(p, rt->source_type) ||
 			    !policydb_type_isvalid(p, rt->target_type) ||
 			    !policydb_class_isvalid(p, rt->target_class)) {
+				kfree(rt);
 				rc = -EINVAL;
 				goto bad;
 			}
-			rc = mls_read_range_helper(&rt->target_range, fp);
-			if (rc)
+			r = kzalloc(sizeof(*r), GFP_KERNEL);
+			if (!r) {
+				kfree(rt);
+				rc = -ENOMEM;
 				goto bad;
-			if (!mls_range_isvalid(p, &rt->target_range)) {
+			}
+			rc = mls_read_range_helper(r, fp);
+			if (rc) {
+				kfree(rt);
+				kfree(r);
+				goto bad;
+			}
+			if (!mls_range_isvalid(p, r)) {
 				printk(KERN_WARNING "SELinux:  rangetrans:  invalid range\n");
+				kfree(rt);
+				kfree(r);
+				goto bad;
+			}
+			rc = hashtab_insert(p->range_tr, rt, r);
+			if (rc) {
+				kfree(rt);
+				kfree(r);
 				goto bad;
 			}
-			lrt = rt;
 		}
+		rangetr_hash_eval(p->range_tr);
 	}
 
 	p->type_attr_map = kmalloc(p->p_types.nprim*sizeof(struct ebitmap), GFP_KERNEL);
diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index cdcc5700946f..26d9adf8542b 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -27,6 +27,8 @@
 #include "symtab.h"
 #include "avtab.h"
 #include "sidtab.h"
+#include "ebitmap.h"
+#include "mls_types.h"
 #include "context.h"
 #include "constraint.h"
 
@@ -113,8 +115,6 @@ struct range_trans {
 	u32 source_type;
 	u32 target_type;
 	u32 target_class;
-	struct mls_range target_range;
-	struct range_trans *next;
 };
 
 /* Boolean data type */
@@ -187,6 +187,8 @@ struct genfs {
 
 /* The policy database */
 struct policydb {
+	int mls_enabled;
+
 	/* symbol tables */
 	struct symtab symtab[SYM_NUM];
 #define p_commons symtab[SYM_COMMONS]
@@ -240,8 +242,8 @@ struct policydb {
 	   fixed labeling behavior. */
 	struct genfs *genfs;
 
-	/* range transitions */
-	struct range_trans *range_tr;
+	/* range transitions table (range_trans_key -> mls_range) */
+	struct hashtab *range_tr;
 
 	/* type -> attribute reverse mapping */
 	struct ebitmap *type_attr_map;
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index b3efae204ac7..cf27b3ee1a95 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -26,6 +26,10 @@
  *
  *  Added support for bounds domain and audit messaged on masked permissions
  *
+ * Updated: Guido Trentalancia <guido@trentalancia.com>
+ *
+ *  Added support for runtime switching of the policy type
+ *
  * Copyright (C) 2008, 2009 NEC Corporation
  * Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P.
  * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
@@ -87,11 +91,10 @@ static u32 latest_granting;
 static int context_struct_to_string(struct context *context, char **scontext,
 				    u32 *scontext_len);
 
-static int context_struct_compute_av(struct context *scontext,
-				     struct context *tcontext,
-				     u16 tclass,
-				     u32 requested,
-				     struct av_decision *avd);
+static void context_struct_compute_av(struct context *scontext,
+				      struct context *tcontext,
+				      u16 tclass,
+				      struct av_decision *avd);
 
 struct selinux_mapping {
 	u16 value; /* policy value */
@@ -196,23 +199,6 @@ static u16 unmap_class(u16 tclass)
 	return tclass;
 }
 
-static u32 unmap_perm(u16 tclass, u32 tperm)
-{
-	if (tclass < current_mapping_size) {
-		unsigned i;
-		u32 kperm = 0;
-
-		for (i = 0; i < current_mapping[tclass].num_perms; i++)
-			if (tperm & (1<<i)) {
-				kperm |= current_mapping[tclass].perms[i];
-				tperm &= ~(1<<i);
-			}
-		return kperm;
-	}
-
-	return tperm;
-}
-
 static void map_decision(u16 tclass, struct av_decision *avd,
 			 int allow_unknown)
 {
@@ -250,6 +236,10 @@ static void map_decision(u16 tclass, struct av_decision *avd,
 	}
 }
 
+int security_mls_enabled(void)
+{
+	return policydb.mls_enabled;
+}
 
 /*
  * Return the boolean value of a constraint expression
@@ -465,7 +455,8 @@ static void security_dump_masked_av(struct context *scontext,
 	char *scontext_name = NULL;
 	char *tcontext_name = NULL;
 	char *permission_names[32];
-	int index, length;
+	int index;
+	u32 length;
 	bool need_comma = false;
 
 	if (!permissions)
@@ -532,7 +523,6 @@ out:
 static void type_attribute_bounds_av(struct context *scontext,
 				     struct context *tcontext,
 				     u16 tclass,
-				     u32 requested,
 				     struct av_decision *avd)
 {
 	struct context lo_scontext;
@@ -553,7 +543,6 @@ static void type_attribute_bounds_av(struct context *scontext,
 		context_struct_compute_av(&lo_scontext,
 					  tcontext,
 					  tclass,
-					  requested,
 					  &lo_avd);
 		if ((lo_avd.allowed & avd->allowed) == avd->allowed)
 			return;		/* no masked permission */
@@ -569,7 +558,6 @@ static void type_attribute_bounds_av(struct context *scontext,
 		context_struct_compute_av(scontext,
 					  &lo_tcontext,
 					  tclass,
-					  requested,
 					  &lo_avd);
 		if ((lo_avd.allowed & avd->allowed) == avd->allowed)
 			return;		/* no masked permission */
@@ -586,7 +574,6 @@ static void type_attribute_bounds_av(struct context *scontext,
 		context_struct_compute_av(&lo_scontext,
 					  &lo_tcontext,
 					  tclass,
-					  requested,
 					  &lo_avd);
 		if ((lo_avd.allowed & avd->allowed) == avd->allowed)
 			return;		/* no masked permission */
@@ -607,11 +594,10 @@ static void type_attribute_bounds_av(struct context *scontext,
  * Compute access vectors based on a context structure pair for
  * the permissions in a particular class.
  */
-static int context_struct_compute_av(struct context *scontext,
-				     struct context *tcontext,
-				     u16 tclass,
-				     u32 requested,
-				     struct av_decision *avd)
+static void context_struct_compute_av(struct context *scontext,
+				      struct context *tcontext,
+				      u16 tclass,
+				      struct av_decision *avd)
 {
 	struct constraint_node *constraint;
 	struct role_allow *ra;
@@ -622,19 +608,14 @@ static int context_struct_compute_av(struct context *scontext,
 	struct ebitmap_node *snode, *tnode;
 	unsigned int i, j;
 
-	/*
-	 * Initialize the access vectors to the default values.
-	 */
 	avd->allowed = 0;
 	avd->auditallow = 0;
 	avd->auditdeny = 0xffffffff;
-	avd->seqno = latest_granting;
-	avd->flags = 0;
 
 	if (unlikely(!tclass || tclass > policydb.p_classes.nprim)) {
 		if (printk_ratelimit())
 			printk(KERN_WARNING "SELinux:  Invalid class %hu\n", tclass);
-		return -EINVAL;
+		return;
 	}
 
 	tclass_datum = policydb.class_val_to_struct[tclass - 1];
@@ -705,9 +686,7 @@ static int context_struct_compute_av(struct context *scontext,
 	 * permission and notice it to userspace via audit.
 	 */
 	type_attribute_bounds_av(scontext, tcontext,
-				 tclass, requested, avd);
-
-	return 0;
+				 tclass, avd);
 }
 
 static int security_validtrans_handle_fail(struct context *ocontext,
@@ -864,7 +843,7 @@ int security_bounded_transition(u32 old_sid, u32 new_sid)
 	if (rc) {
 		char *old_name = NULL;
 		char *new_name = NULL;
-		int length;
+		u32 length;
 
 		if (!context_struct_to_string(old_context,
 					      &old_name, &length) &&
@@ -886,110 +865,116 @@ out:
 	return rc;
 }
 
-
-static int security_compute_av_core(u32 ssid,
-				    u32 tsid,
-				    u16 tclass,
-				    u32 requested,
-				    struct av_decision *avd)
+static void avd_init(struct av_decision *avd)
 {
-	struct context *scontext = NULL, *tcontext = NULL;
-	int rc = 0;
-
-	scontext = sidtab_search(&sidtab, ssid);
-	if (!scontext) {
-		printk(KERN_ERR "SELinux: %s:  unrecognized SID %d\n",
-		       __func__, ssid);
-		return -EINVAL;
-	}
-	tcontext = sidtab_search(&sidtab, tsid);
-	if (!tcontext) {
-		printk(KERN_ERR "SELinux: %s:  unrecognized SID %d\n",
-		       __func__, tsid);
-		return -EINVAL;
-	}
-
-	rc = context_struct_compute_av(scontext, tcontext, tclass,
-				       requested, avd);
-
-	/* permissive domain? */
-	if (ebitmap_get_bit(&policydb.permissive_map, scontext->type))
-		avd->flags |= AVD_FLAGS_PERMISSIVE;
-
-	return rc;
+	avd->allowed = 0;
+	avd->auditallow = 0;
+	avd->auditdeny = 0xffffffff;
+	avd->seqno = latest_granting;
+	avd->flags = 0;
 }
 
+
 /**
  * security_compute_av - Compute access vector decisions.
  * @ssid: source security identifier
  * @tsid: target security identifier
  * @tclass: target security class
- * @requested: requested permissions
  * @avd: access vector decisions
  *
  * Compute a set of access vector decisions based on the
  * SID pair (@ssid, @tsid) for the permissions in @tclass.
- * Return -%EINVAL if any of the parameters are invalid or %0
- * if the access vector decisions were computed successfully.
  */
-int security_compute_av(u32 ssid,
-			u32 tsid,
-			u16 orig_tclass,
-			u32 orig_requested,
-			struct av_decision *avd)
+void security_compute_av(u32 ssid,
+			 u32 tsid,
+			 u16 orig_tclass,
+			 struct av_decision *avd)
 {
 	u16 tclass;
-	u32 requested;
-	int rc;
+	struct context *scontext = NULL, *tcontext = NULL;
 
 	read_lock(&policy_rwlock);
-
+	avd_init(avd);
 	if (!ss_initialized)
 		goto allow;
 
-	requested = unmap_perm(orig_tclass, orig_requested);
+	scontext = sidtab_search(&sidtab, ssid);
+	if (!scontext) {
+		printk(KERN_ERR "SELinux: %s:  unrecognized SID %d\n",
+		       __func__, ssid);
+		goto out;
+	}
+
+	/* permissive domain? */
+	if (ebitmap_get_bit(&policydb.permissive_map, scontext->type))
+		avd->flags |= AVD_FLAGS_PERMISSIVE;
+
+	tcontext = sidtab_search(&sidtab, tsid);
+	if (!tcontext) {
+		printk(KERN_ERR "SELinux: %s:  unrecognized SID %d\n",
+		       __func__, tsid);
+		goto out;
+	}
+
 	tclass = unmap_class(orig_tclass);
 	if (unlikely(orig_tclass && !tclass)) {
 		if (policydb.allow_unknown)
 			goto allow;
-		rc = -EINVAL;
 		goto out;
 	}
-	rc = security_compute_av_core(ssid, tsid, tclass, requested, avd);
+	context_struct_compute_av(scontext, tcontext, tclass, avd);
 	map_decision(orig_tclass, avd, policydb.allow_unknown);
 out:
 	read_unlock(&policy_rwlock);
-	return rc;
+	return;
 allow:
 	avd->allowed = 0xffffffff;
-	avd->auditallow = 0;
-	avd->auditdeny = 0xffffffff;
-	avd->seqno = latest_granting;
-	avd->flags = 0;
-	rc = 0;
 	goto out;
 }
 
-int security_compute_av_user(u32 ssid,
-			     u32 tsid,
-			     u16 tclass,
-			     u32 requested,
-			     struct av_decision *avd)
+void security_compute_av_user(u32 ssid,
+			      u32 tsid,
+			      u16 tclass,
+			      struct av_decision *avd)
 {
-	int rc;
+	struct context *scontext = NULL, *tcontext = NULL;
 
-	if (!ss_initialized) {
-		avd->allowed = 0xffffffff;
-		avd->auditallow = 0;
-		avd->auditdeny = 0xffffffff;
-		avd->seqno = latest_granting;
-		return 0;
+	read_lock(&policy_rwlock);
+	avd_init(avd);
+	if (!ss_initialized)
+		goto allow;
+
+	scontext = sidtab_search(&sidtab, ssid);
+	if (!scontext) {
+		printk(KERN_ERR "SELinux: %s:  unrecognized SID %d\n",
+		       __func__, ssid);
+		goto out;
 	}
 
-	read_lock(&policy_rwlock);
-	rc = security_compute_av_core(ssid, tsid, tclass, requested, avd);
+	/* permissive domain? */
+	if (ebitmap_get_bit(&policydb.permissive_map, scontext->type))
+		avd->flags |= AVD_FLAGS_PERMISSIVE;
+
+	tcontext = sidtab_search(&sidtab, tsid);
+	if (!tcontext) {
+		printk(KERN_ERR "SELinux: %s:  unrecognized SID %d\n",
+		       __func__, tsid);
+		goto out;
+	}
+
+	if (unlikely(!tclass)) {
+		if (policydb.allow_unknown)
+			goto allow;
+		goto out;
+	}
+
+	context_struct_compute_av(scontext, tcontext, tclass, avd);
+ out:
 	read_unlock(&policy_rwlock);
-	return rc;
+	return;
+allow:
+	avd->allowed = 0xffffffff;
+	goto out;
 }
 
 /*
@@ -1565,7 +1550,10 @@ static int clone_sid(u32 sid,
 {
 	struct sidtab *s = arg;
 
-	return sidtab_insert(s, sid, context);
+	if (sid > SECINITSID_NUM)
+		return sidtab_insert(s, sid, context);
+	else
+		return 0;
 }
 
 static inline int convert_context_handle_invalid_context(struct context *context)
@@ -1606,12 +1594,17 @@ static int convert_context(u32 key,
 {
 	struct convert_context_args *args;
 	struct context oldc;
+	struct ocontext *oc;
+	struct mls_range *range;
 	struct role_datum *role;
 	struct type_datum *typdatum;
 	struct user_datum *usrdatum;
 	char *s;
 	u32 len;
-	int rc;
+	int rc = 0;
+
+	if (key <= SECINITSID_NUM)
+		goto out;
 
 	args = p;
 
@@ -1673,9 +1666,39 @@ static int convert_context(u32 key,
 		goto bad;
 	c->type = typdatum->value;
 
-	rc = mls_convert_context(args->oldp, args->newp, c);
-	if (rc)
-		goto bad;
+	/* Convert the MLS fields if dealing with MLS policies */
+	if (args->oldp->mls_enabled && args->newp->mls_enabled) {
+		rc = mls_convert_context(args->oldp, args->newp, c);
+		if (rc)
+			goto bad;
+	} else if (args->oldp->mls_enabled && !args->newp->mls_enabled) {
+		/*
+		 * Switching between MLS and non-MLS policy:
+		 * free any storage used by the MLS fields in the
+		 * context for all existing entries in the sidtab.
+		 */
+		mls_context_destroy(c);
+	} else if (!args->oldp->mls_enabled && args->newp->mls_enabled) {
+		/*
+		 * Switching between non-MLS and MLS policy:
+		 * ensure that the MLS fields of the context for all
+		 * existing entries in the sidtab are filled in with a
+		 * suitable default value, likely taken from one of the
+		 * initial SIDs.
+		 */
+		oc = args->newp->ocontexts[OCON_ISID];
+		while (oc && oc->sid[0] != SECINITSID_UNLABELED)
+			oc = oc->next;
+		if (!oc) {
+			printk(KERN_ERR "SELinux:  unable to look up"
+				" the initial SIDs list\n");
+			goto bad;
+		}
+		range = &oc->context[0].range;
+		rc = mls_range_set(c, range);
+		if (rc)
+			goto bad;
+	}
 
 	/* Check the validity of the new context. */
 	if (!policydb_context_isvalid(args->newp, c)) {
@@ -1771,9 +1794,17 @@ int security_load_policy(void *data, size_t len)
 	if (policydb_read(&newpolicydb, fp))
 		return -EINVAL;
 
-	if (sidtab_init(&newsidtab)) {
+	/* If switching between different policy types, log MLS status */
+	if (policydb.mls_enabled && !newpolicydb.mls_enabled)
+		printk(KERN_INFO "SELinux: Disabling MLS support...\n");
+	else if (!policydb.mls_enabled && newpolicydb.mls_enabled)
+		printk(KERN_INFO "SELinux: Enabling MLS support...\n");
+
+	rc = policydb_load_isids(&newpolicydb, &newsidtab);
+	if (rc) {
+		printk(KERN_ERR "SELinux:  unable to load the initial SIDs\n");
 		policydb_destroy(&newpolicydb);
-		return -ENOMEM;
+		return rc;
 	}
 
 	if (selinux_set_mapping(&newpolicydb, secclass_map,
@@ -1800,8 +1831,12 @@ int security_load_policy(void *data, size_t len)
 	args.oldp = &policydb;
 	args.newp = &newpolicydb;
 	rc = sidtab_map(&newsidtab, convert_context, &args);
-	if (rc)
+	if (rc) {
+		printk(KERN_ERR "SELinux:  unable to convert the internal"
+			" representation of contexts in the new SID"
+			" table\n");
 		goto err;
+	}
 
 	/* Save the old policydb and SID table to free later. */
 	memcpy(&oldpolicydb, &policydb, sizeof policydb);
@@ -2397,7 +2432,7 @@ int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid)
 	u32 len;
 	int rc = 0;
 
-	if (!ss_initialized || !selinux_mls_enabled) {
+	if (!ss_initialized || !policydb.mls_enabled) {
 		*new_sid = sid;
 		goto out;
 	}
@@ -2498,7 +2533,7 @@ int security_net_peersid_resolve(u32 nlbl_sid, u32 nlbl_type,
 	/* we don't need to check ss_initialized here since the only way both
 	 * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the
 	 * security server was initialized and ss_initialized was true */
-	if (!selinux_mls_enabled) {
+	if (!policydb.mls_enabled) {
 		*peer_sid = SECSID_NULL;
 		return 0;
 	}
@@ -2555,7 +2590,7 @@ int security_get_classes(char ***classes, int *nclasses)
 	read_lock(&policy_rwlock);
 
 	*nclasses = policydb.p_classes.nprim;
-	*classes = kcalloc(*nclasses, sizeof(*classes), GFP_ATOMIC);
+	*classes = kcalloc(*nclasses, sizeof(**classes), GFP_ATOMIC);
 	if (!*classes)
 		goto out;
 
@@ -2602,7 +2637,7 @@ int security_get_permissions(char *class, char ***perms, int *nperms)
 	}
 
 	*nperms = match->permissions.nprim;
-	*perms = kcalloc(*nperms, sizeof(*perms), GFP_ATOMIC);
+	*perms = kcalloc(*nperms, sizeof(**perms), GFP_ATOMIC);
 	if (!*perms)
 		goto out;