1 files changed, 154 insertions, 119 deletions

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;