TOMOYO: Fix memory leak upon file open.

commit eae61f3c upstream.

In tomoyo_check_open_permission() since 2.6.36, TOMOYO was by error
recalculating already calculated pathname when checking allow_rewrite
permission. As a result, memory will leak whenever a file is opened for writing
without O_APPEND flag. Also, performance will degrade because TOMOYO is
calculating pathname regardless of profile configuration.
This patch fixes the leak and performance degrade.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

security/tomoyo/file.c

@@ -927,7 +927,7 @@ int tomoyo_check_open_permission(struct tomoyo_domain_info *domain,
 				 struct path *path, const int flag)
 {
 	const u8 acc_mode = ACC_MODE(flag);
-	int error = -ENOMEM;
+	int error = 0;
 	struct tomoyo_path_info buf;
 	struct tomoyo_request_info r;
 	int idx;
@@ -938,9 +938,6 @@ int tomoyo_check_open_permission(struct tomoyo_domain_info *domain,
 	buf.name = NULL;
 	r.mode = TOMOYO_CONFIG_DISABLED;
 	idx = tomoyo_read_lock();
-	if (!tomoyo_get_realpath(&buf, path))
-		goto out;
-	error = 0;
 	/*
 	 * If the filename is specified by "deny_rewrite" keyword,
 	 * we need to check "allow_rewrite" permission when the filename is not