1 files changed, 71 insertions, 31 deletions

diff --git a/security/security.c b/security/security.c
index 6bc591f77b1a..c900d7a1441a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -52,33 +52,96 @@ static __initdata bool debug;
 			pr_info(__VA_ARGS__);			\
 	} while (0)
 
+static bool __init is_enabled(struct lsm_info *lsm)
+{
+	if (!lsm->enabled || *lsm->enabled)
+		return true;
+
+	return false;
+}
+
+/* Mark an LSM's enabled flag. */
+static int lsm_enabled_true __initdata = 1;
+static int lsm_enabled_false __initdata = 0;
+static void __init set_enabled(struct lsm_info *lsm, bool enabled)
+{
+	/*
+	 * When an LSM hasn't configured an enable variable, we can use
+	 * a hard-coded location for storing the default enabled state.
+	 */
+	if (!lsm->enabled) {
+		if (enabled)
+			lsm->enabled = &lsm_enabled_true;
+		else
+			lsm->enabled = &lsm_enabled_false;
+	} else if (lsm->enabled == &lsm_enabled_true) {
+		if (!enabled)
+			lsm->enabled = &lsm_enabled_false;
+	} else if (lsm->enabled == &lsm_enabled_false) {
+		if (enabled)
+			lsm->enabled = &lsm_enabled_true;
+	} else {
+		*lsm->enabled = enabled;
+	}
+}
+
+/* Is an LSM allowed to be initialized? */
+static bool __init lsm_allowed(struct lsm_info *lsm)
+{
+	/* Skip if the LSM is disabled. */
+	if (!is_enabled(lsm))
+		return false;
+
+	/* Skip major-specific checks if not a major LSM. */
+	if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0)
+		return true;
+
+	/* Disabled if this LSM isn't the chosen one. */
+	if (strcmp(lsm->name, chosen_lsm) != 0)
+		return false;
+
+	return true;
+}
+
+/* Check if LSM should be initialized. */
+static void __init maybe_initialize_lsm(struct lsm_info *lsm)
+{
+	int enabled = lsm_allowed(lsm);
+
+	/* Record enablement (to handle any following exclusive LSMs). */
+	set_enabled(lsm, enabled);
+
+	/* If selected, initialize the LSM. */
+	if (enabled) {
+		int ret;
+
+		init_debug("initializing %s\n", lsm->name);
+		ret = lsm->init();
+		WARN(ret, "%s failed to initialize: %d\n", lsm->name, ret);
+	}
+}
+
 static void __init ordered_lsm_init(void)
 {
 	struct lsm_info *lsm;
-	int ret;
 
 	for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
 		if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) != 0)
 			continue;
 
-		init_debug("initializing %s\n", lsm->name);
-		ret = lsm->init();
-		WARN(ret, "%s failed to initialize: %d\n", lsm->name, ret);
+		maybe_initialize_lsm(lsm);
 	}
 }
 
 static void __init major_lsm_init(void)
 {
 	struct lsm_info *lsm;
-	int ret;
 
 	for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
 		if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0)
 			continue;
 
-		init_debug("initializing %s\n", lsm->name);
-		ret = lsm->init();
-		WARN(ret, "%s failed to initialize: %d\n", lsm->name, ret);
+		maybe_initialize_lsm(lsm);
 	}
 }
 
@@ -169,29 +232,6 @@ static int lsm_append(char *new, char **result)
 }
 
 /**
- * security_module_enable - Load given security module on boot ?
- * @module: the name of the module
- *
- * Each LSM must pass this method before registering its own operations
- * to avoid security registration races. This method may also be used
- * to check if your LSM is currently loaded during kernel initialization.
- *
- * Returns:
- *
- * true if:
- *
- * - The passed LSM is the one chosen by user at boot time,
- * - or the passed LSM is configured as the default and the user did not
- *   choose an alternate LSM at boot time.
- *
- * Otherwise, return false.
- */
-int __init security_module_enable(const char *module)
-{
-	return !strcmp(module, chosen_lsm);
-}
-
-/**
  * security_add_hooks - Add a modules hooks to the hook lists.
  * @hooks: the hooks to add
  * @count: the number of hooks to add