lsm: rename/rework ordered_lsm_parse() to lsm_order_parse()

Rename ordered_lsm_parse() to lsm_order_parse() for the sake of
consistency with the other LSM initialization routines, and also
do some minor rework of the function.  Aside from some minor style
decisions, the majority of the rework involved shuffling the order
of the LSM_FLAG_LEGACY and LSM_ORDER_FIRST code so that the
LSM_FLAG_LEGACY checks are handled first; it is important to note
that this doesn't affect the order in which the LSMs are registered.

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

Author: pcmoore

security/lsm_init.c

@@ -228,83 +228,75 @@ static void __init initialize_lsm(struct lsm_info *lsm)
 	}
 }
 
-/* Populate ordered LSMs list from comma-separated LSM name list. */
-static void __init ordered_lsm_parse(const char *order, const char *origin)
+/**
+ * lsm_order_parse - Parse the comma delimited LSM list
+ * @list: LSM list
+ * @src: source of the list
+ */
+static void __init lsm_order_parse(const char *list, const char *src)
 {
 	struct lsm_info *lsm;
 	char *sep, *name, *next;
 
-	/* LSM_ORDER_FIRST is always first. */
-	lsm_for_each_raw(lsm) {
-		if (lsm->order == LSM_ORDER_FIRST)
-			lsm_order_append(lsm, "  first");
-	}
-
-	/* Process "security=", if given. */
+	/* Handle any Legacy LSM exclusions if one was specified. */
 	if (lsm_order_legacy) {
-		struct lsm_info *major;
-
 		/*
-		 * To match the original "security=" behavior, this
-		 * explicitly does NOT fallback to another Legacy Major
-		 * if the selected one was separately disabled: disable
-		 * all non-matching Legacy Major LSMs.
+		 * To match the original "security=" behavior, this explicitly
+		 * does NOT fallback to another Legacy Major if the selected
+		 * one was separately disabled: disable all non-matching
+		 * Legacy Major LSMs.
 		 */
-		lsm_for_each_raw(major) {
-			if ((major->flags & LSM_FLAG_LEGACY_MAJOR) &&
-			    strcmp(major->id->name, lsm_order_legacy) != 0) {
-				lsm_enabled_set(major, false);
+		lsm_for_each_raw(lsm) {
+			if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) &&
+			     strcmp(lsm->id->name, lsm_order_legacy)) {
+				lsm_enabled_set(lsm, false);
 				init_debug("security=%s disabled: %s (only one legacy major LSM)\n",
-					   lsm_order_legacy, major->id->name);
+					   lsm_order_legacy, lsm->id->name);
 			}
 		}
 	}
 
-	sep = kstrdup(order, GFP_KERNEL);
+	/* LSM_ORDER_FIRST */
+	lsm_for_each_raw(lsm) {
+		if (lsm->order == LSM_ORDER_FIRST)
+			lsm_order_append(lsm, "first");
+	}
+
+	/* Normal or "mutable" LSMs */
+	sep = kstrdup(list, GFP_KERNEL);
 	next = sep;
 	/* Walk the list, looking for matching LSMs. */
 	while ((name = strsep(&next, ",")) != NULL) {
-		bool found = false;
-
 		lsm_for_each_raw(lsm) {
-			if (strcmp(lsm->id->name, name) == 0) {
-				if (lsm->order == LSM_ORDER_MUTABLE)
-					lsm_order_append(lsm, origin);
-				found = true;
-			}
+			if (!strcmp(lsm->id->name, name) &&
+			    lsm->order == LSM_ORDER_MUTABLE)
+				lsm_order_append(lsm, src);
 		}
-
-		if (!found)
-			init_debug("%s ignored: %s (not built into kernel)\n",
-				   origin, name);
 	}
+	kfree(sep);
 
-	/* Process "security=", if given. */
+	/* Legacy LSM if specified. */
 	if (lsm_order_legacy) {
 		lsm_for_each_raw(lsm) {
-			if (lsm_order_exists(lsm))
-				continue;
-			if (strcmp(lsm->id->name, lsm_order_legacy) == 0)
-				lsm_order_append(lsm, "security=");
+			if (!strcmp(lsm->id->name, lsm_order_legacy))
+				lsm_order_append(lsm, src);
 		}
 	}
 
-	/* LSM_ORDER_LAST is always last. */
+	/* LSM_ORDER_LAST */
 	lsm_for_each_raw(lsm) {
 		if (lsm->order == LSM_ORDER_LAST)
-			lsm_order_append(lsm, "   last");
+			lsm_order_append(lsm, "last");
 	}
 
-	/* Disable all LSMs not in the ordered list. */
+	/* Disable all LSMs not previously enabled. */
 	lsm_for_each_raw(lsm) {
 		if (lsm_order_exists(lsm))
 			continue;
 		lsm_enabled_set(lsm, false);
 		init_debug("%s skipped: %s (not in requested order)\n",
-			   origin, lsm->id->name);
+			   src, lsm->id->name);
 	}
-
-	kfree(sep);
 }
 
 /**
@@ -322,9 +314,9 @@ static void __init lsm_init_ordered(void)
 				lsm_order_legacy, lsm_order_cmdline);
 			lsm_order_legacy = NULL;
 		}
-		ordered_lsm_parse(lsm_order_cmdline, "cmdline");
+		lsm_order_parse(lsm_order_cmdline, "cmdline");
 	} else
-		ordered_lsm_parse(lsm_order_builtin, "builtin");
+		lsm_order_parse(lsm_order_builtin, "builtin");
 
 	lsm_order_for_each(lsm) {
 		lsm_prepare(*lsm);