LSM: Add all exclusive LSMs to ordered initialization

This removes CONFIG_DEFAULT_SECURITY in favor of the explicit ordering
offered by CONFIG_LSM and adds all the exclusive LSMs to the ordered
LSM initialization. The old meaning of CONFIG_DEFAULT_SECURITY is now
captured by which exclusive LSM is listed first in the LSM order. All
LSMs not added to the ordered list are explicitly disabled.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

diff --git a/security/security.c b/security/security.c
index a8dd7de..2d08a53 100644 (file)
--- a/security/security.c
+++ b/security/security.c
@@ -169,8 +169,6 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
        char *sep, *name, *next;
 
        /* Process "security=", if given. */
-       if (!chosen_major_lsm)
-               chosen_major_lsm = CONFIG_DEFAULT_SECURITY;
        if (chosen_major_lsm) {
                struct lsm_info *major;
 
@@ -198,8 +196,7 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
                bool found = false;
 
                for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
-                       if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0 &&
-                           strcmp(lsm->name, name) == 0) {
+                       if (strcmp(lsm->name, name) == 0) {
                                append_ordered_lsm(lsm, origin);
                                found = true;
                        }
@@ -208,6 +205,25 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
                if (!found)
                        init_debug("%s ignored: %s\n", origin, name);
        }
+
+       /* Process "security=", if given. */
+       if (chosen_major_lsm) {
+               for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
+                       if (exists_ordered_lsm(lsm))
+                               continue;
+                       if (strcmp(lsm->name, chosen_major_lsm) == 0)
+                               append_ordered_lsm(lsm, "security=");
+               }
+       }
+
+       /* Disable all LSMs not in the ordered list. */
+       for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
+               if (exists_ordered_lsm(lsm))
+                       continue;
+               set_enabled(lsm, false);
+               init_debug("%s disabled: %s\n", origin, lsm->name);
+       }
+
        kfree(sep);
 }
 
@@ -229,22 +245,6 @@ static void __init ordered_lsm_init(void)
        kfree(ordered_lsms);
 }
 
-static void __init major_lsm_init(void)
-{
-       struct lsm_info *lsm;
-
-       for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
-               if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0)
-                       continue;
-
-               /* Enable this LSM, if it is not already set. */
-               if (!lsm->enabled)
-                       lsm->enabled = &lsm_enabled_true;
-
-               maybe_initialize_lsm(lsm);
-       }
-}
-
 /**
  * security_init - initializes the security framework
  *
@@ -271,11 +271,6 @@ int __init security_init(void)
        /* Load LSMs in specified order. */
        ordered_lsm_init();
 
-       /*
-        * Load all the remaining security modules.
-        */
-       major_lsm_init();
-
        return 0;
 }