lsm: rework the LSM enable/disable setter/getter functions

In addition to style changes, rename set_enabled() to lsm_enabled_set()
and is_enabled() to lsm_is_enabled() to better fit within the LSM
initialization code.

Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Author: pcmoore

security/lsm_init.c

@@ -10,6 +10,10 @@
 
 #include "lsm.h"
 
+/* LSM enabled constants. */
+static __initdata int lsm_enabled_true = 1;
+static __initdata int lsm_enabled_false = 0;
+
 /* Pointers to LSM sections defined in include/asm-generic/vmlinux.lds.h */
 extern struct lsm_info __start_lsm_info[], __end_lsm_info[];
 extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[];
@@ -75,37 +79,33 @@ static int __init lsm_debug_enable(char *str)
 }
 __setup("lsm.debug", lsm_debug_enable);
 
-/* 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)
+/**
+ * lsm_enabled_set - Mark a LSM as enabled
+ * @lsm: LSM definition
+ * @enabled: enabled flag
+ */
+static void __init lsm_enabled_set(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;
+	if (!lsm->enabled ||
+	    lsm->enabled == &lsm_enabled_true ||
+	    lsm->enabled == &lsm_enabled_false) {
+		lsm->enabled = enabled ? &lsm_enabled_true : &lsm_enabled_false;
 	} else {
 		*lsm->enabled = enabled;
 	}
 }
 
-static inline bool is_enabled(struct lsm_info *lsm)
+/**
+ * lsm_is_enabled - Determine if a LSM is enabled
+ * @lsm: LSM definition
+ */
+static inline bool lsm_is_enabled(struct lsm_info *lsm)
 {
-	if (!lsm->enabled)
-		return false;
-
-	return *lsm->enabled;
+	return (lsm->enabled ? *lsm->enabled : false);
 }
 
 /* Is an LSM already listed in the ordered LSMs list? */
@@ -139,7 +139,7 @@ static void __init append_ordered_lsm(struct lsm_info *lsm, const char *from)
 	lsm_idlist[last_lsm++] = lsm->id;
 
 	init_debug("%s ordered: %s (%s)\n", from, lsm->id->name,
-		   is_enabled(lsm) ? "enabled" : "disabled");
+		   lsm_is_enabled(lsm) ? "enabled" : "disabled");
 }
 
 static void __init lsm_set_blob_size(int *need, int *lbs)
@@ -162,17 +162,17 @@ static void __init lsm_prepare(struct lsm_info *lsm)
 {
 	struct lsm_blob_sizes *blobs;
 
-	if (!is_enabled(lsm)) {
-		set_enabled(lsm, false);
+	if (!lsm_is_enabled(lsm)) {
+		lsm_enabled_set(lsm, false);
 		return;
 	} else if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && lsm_exclusive) {
 		init_debug("exclusive disabled: %s\n", lsm->id->name);
-		set_enabled(lsm, false);
+		lsm_enabled_set(lsm, false);
 		return;
 	}
 
 	/* Mark the LSM as enabled. */
-	set_enabled(lsm, true);
+	lsm_enabled_set(lsm, true);
 	if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && !lsm_exclusive) {
 		init_debug("exclusive chosen:   %s\n", lsm->id->name);
 		lsm_exclusive = lsm;
@@ -206,7 +206,7 @@ static void __init lsm_prepare(struct lsm_info *lsm)
 /* Initialize a given LSM, if it is enabled. */
 static void __init initialize_lsm(struct lsm_info *lsm)
 {
-	if (is_enabled(lsm)) {
+	if (lsm_is_enabled(lsm)) {
 		int ret;
 
 		init_debug("initializing %s\n", lsm->id->name);
@@ -240,7 +240,7 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
 		lsm_for_each_raw(major) {
 			if ((major->flags & LSM_FLAG_LEGACY_MAJOR) &&
 			    strcmp(major->id->name, lsm_order_legacy) != 0) {
-				set_enabled(major, false);
+				lsm_enabled_set(major, false);
 				init_debug("security=%s disabled: %s (only one legacy major LSM)\n",
 					   lsm_order_legacy, major->id->name);
 			}
@@ -286,7 +286,7 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
 	lsm_for_each_raw(lsm) {
 		if (exists_ordered_lsm(lsm))
 			continue;
-		set_enabled(lsm, false);
+		lsm_enabled_set(lsm, false);
 		init_debug("%s skipped: %s (not in requested order)\n",
 			   origin, lsm->id->name);
 	}
@@ -319,12 +319,12 @@ static void __init lsm_init_ordered(void)
 
 	pr_info("initializing lsm=");
 	lsm_early_for_each_raw(early) {
-		if (is_enabled(early))
+		if (lsm_is_enabled(early))
 			pr_cont("%s%s",
 				first++ == 0 ? "" : ",", early->id->name);
 	}
 	lsm_order_for_each(lsm) {
-		if (is_enabled(*lsm))
+		if (lsm_is_enabled(*lsm))
 			pr_cont("%s%s",
 				first++ == 0 ? "" : ",", (*lsm)->id->name);
 	}
@@ -440,7 +440,7 @@ int __init security_init(void)
 	 */
 	lsm_early_for_each_raw(lsm) {
 		init_debug("  early started: %s (%s)\n", lsm->id->name,
-			   is_enabled(lsm) ? "enabled" : "disabled");
+			   lsm_is_enabled(lsm) ? "enabled" : "disabled");
 	}
 
 	/* Load LSMs in specified order. */