SELinux: drop load_mutex in security_load_policy
Eric Paris [Mon, 9 Jun 2008 19:58:04 +0000 (15:58 -0400)]
We used to protect against races of policy load in security_load_policy
by using the load_mutex.  Since then we have added a new mutex,
sel_mutex, in sel_write_load() which is always held across all calls to
security_load_policy we are covered and can safely just drop this one.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>

security/selinux/ss/services.c

index f26a8ca..543fd0f 100644 (file)
@@ -71,7 +71,6 @@ int selinux_policycap_openperm;
 extern const struct selinux_class_perm selinux_class_perm;
 
 static DEFINE_RWLOCK(policy_rwlock);
-static DEFINE_MUTEX(load_mutex);
 
 static struct sidtab sidtab;
 struct policydb policydb;
@@ -1453,17 +1452,13 @@ int security_load_policy(void *data, size_t len)
        int rc = 0;
        struct policy_file file = { data, len }, *fp = &file;
 
-       mutex_lock(&load_mutex);
-
        if (!ss_initialized) {
                avtab_cache_init();
                if (policydb_read(&policydb, fp)) {
-                       mutex_unlock(&load_mutex);
                        avtab_cache_destroy();
                        return -EINVAL;
                }
                if (policydb_load_isids(&policydb, &sidtab)) {
-                       mutex_unlock(&load_mutex);
                        policydb_destroy(&policydb);
                        avtab_cache_destroy();
                        return -EINVAL;
@@ -1472,7 +1467,6 @@ int security_load_policy(void *data, size_t len)
                if (validate_classes(&policydb)) {
                        printk(KERN_ERR
                               "SELinux:  the definition of a class is incorrect\n");
-                       mutex_unlock(&load_mutex);
                        sidtab_destroy(&sidtab);
                        policydb_destroy(&policydb);
                        avtab_cache_destroy();
@@ -1482,7 +1476,6 @@ int security_load_policy(void *data, size_t len)
                policydb_loaded_version = policydb.policyvers;
                ss_initialized = 1;
                seqno = ++latest_granting;
-               mutex_unlock(&load_mutex);
                selinux_complete_init();
                avc_ss_reset(seqno);
                selnl_notify_policyload(seqno);
@@ -1495,13 +1488,10 @@ int security_load_policy(void *data, size_t len)
        sidtab_hash_eval(&sidtab, "sids");
 #endif
 
-       if (policydb_read(&newpolicydb, fp)) {
-               mutex_unlock(&load_mutex);
+       if (policydb_read(&newpolicydb, fp))
                return -EINVAL;
-       }
 
        if (sidtab_init(&newsidtab)) {
-               mutex_unlock(&load_mutex);
                policydb_destroy(&newpolicydb);
                return -ENOMEM;
        }
@@ -1549,7 +1539,6 @@ int security_load_policy(void *data, size_t len)
        seqno = ++latest_granting;
        policydb_loaded_version = policydb.policyvers;
        write_unlock_irq(&policy_rwlock);
-       mutex_unlock(&load_mutex);
 
        /* Free the old policydb and SID table. */
        policydb_destroy(&oldpolicydb);
@@ -1563,7 +1552,6 @@ int security_load_policy(void *data, size_t len)
        return 0;
 
 err:
-       mutex_unlock(&load_mutex);
        sidtab_destroy(&newsidtab);
        policydb_destroy(&newpolicydb);
        return rc;