1 files changed, 154 insertions, 119 deletions

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index b3efae2..cf27b3e 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;