selinux: refactor sidtab conversion

This is a purely cosmetic change that encapsulates the three-step sidtab
conversion logic (shutdown -> clone -> map) into a single function
defined in sidtab.c (as opposed to services.c).
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
[PM: whitespaces fixes to make checkpatch happy]
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/ss/services.c

@@ -1880,19 +1880,6 @@ int security_change_sid(struct selinux_state *state,
 				    out_sid, false);
 }
 
-/* Clone the SID into the new SID table. */
-static int clone_sid(u32 sid,
-		     struct context *context,
-		     void *arg)
-{
-	struct sidtab *s = arg;
-
-	if (sid > SECINITSID_NUM)
-		return sidtab_insert(s, sid, context);
-	else
-		return 0;
-}
-
 static inline int convert_context_handle_invalid_context(
 	struct selinux_state *state,
 	struct context *context)
@@ -2186,13 +2173,6 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
 		goto err;
 	}
 
-	/* Clone the SID table. */
-	sidtab_shutdown(sidtab);
-
-	rc = sidtab_map(sidtab, clone_sid, &newsidtab);
-	if (rc)
-		goto err;
-
 	/*
 	 * Convert the internal representations of contexts
 	 * in the new SID table.
@@ -2200,7 +2180,7 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
 	args.state = state;
 	args.oldp = policydb;
 	args.newp = newpolicydb;
-	rc = sidtab_map(&newsidtab, convert_context, &args);
+	rc = sidtab_convert(sidtab, &newsidtab, convert_context, &args);
 	if (rc) {
 		pr_err("SELinux:  unable to convert the internal"
 			" representation of contexts in the new SID"

security/selinux/ss/sidtab.c

@@ -116,11 +116,11 @@ struct context *sidtab_search_force(struct sidtab *s, u32 sid)
 	return sidtab_search_core(s, sid, 1);
 }
 
-int sidtab_map(struct sidtab *s,
-	       int (*apply) (u32 sid,
-			     struct context *context,
-			     void *args),
-	       void *args)
+static int sidtab_map(struct sidtab *s,
+		      int (*apply)(u32 sid,
+				   struct context *context,
+				   void *args),
+		      void *args)
 {
 	int i, rc = 0;
 	struct sidtab_node *cur;
@@ -141,6 +141,37 @@ int sidtab_map(struct sidtab *s,
 	return rc;
 }
 
+/* Clone the SID into the new SID table. */
+static int clone_sid(u32 sid, struct context *context, void *arg)
+{
+	struct sidtab *s = arg;
+
+	if (sid > SECINITSID_NUM)
+		return sidtab_insert(s, sid, context);
+	else
+		return 0;
+}
+
+int sidtab_convert(struct sidtab *s, struct sidtab *news,
+		   int (*convert)(u32 sid,
+				  struct context *context,
+				  void *args),
+		   void *args)
+{
+	unsigned long flags;
+	int rc;
+
+	spin_lock_irqsave(&s->lock, flags);
+	s->shutdown = 1;
+	spin_unlock_irqrestore(&s->lock, flags);
+
+	rc = sidtab_map(s, clone_sid, news);
+	if (rc)
+		return rc;
+
+	return sidtab_map(news, convert, args);
+}
+
 static void sidtab_update_cache(struct sidtab *s, struct sidtab_node *n, int loc)
 {
 	BUG_ON(loc >= SIDTAB_CACHE_LEN);
@@ -295,12 +326,3 @@ void sidtab_set(struct sidtab *dst, struct sidtab *src)
 		dst->cache[i] = NULL;
 	spin_unlock_irqrestore(&src->lock, flags);
 }
-
-void sidtab_shutdown(struct sidtab *s)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&s->lock, flags);
-	s->shutdown = 1;
-	spin_unlock_irqrestore(&s->lock, flags);
-}

security/selinux/ss/sidtab.h

@@ -37,11 +37,11 @@ int sidtab_insert(struct sidtab *s, u32 sid, struct context *context);
 struct context *sidtab_search(struct sidtab *s, u32 sid);
 struct context *sidtab_search_force(struct sidtab *s, u32 sid);
 
-int sidtab_map(struct sidtab *s,
-	       int (*apply) (u32 sid,
-			     struct context *context,
-			     void *args),
-	       void *args);
+int sidtab_convert(struct sidtab *s, struct sidtab *news,
+		   int (*apply)(u32 sid,
+				struct context *context,
+				void *args),
+		   void *args);
 
 int sidtab_context_to_sid(struct sidtab *s,
 			  struct context *context,
@@ -50,7 +50,6 @@ int sidtab_context_to_sid(struct sidtab *s,
 void sidtab_hash_eval(struct sidtab *h, char *tag);
 void sidtab_destroy(struct sidtab *s);
 void sidtab_set(struct sidtab *dst, struct sidtab *src);
-void sidtab_shutdown(struct sidtab *s);
 
 #endif	/* _SS_SIDTAB_H_ */