TOMOYO: Loosen parameter check for mount operation.

If invalid combination of mount flags are given, it will be rejected later.
Thus, no need for TOMOYO to reject invalid combination of mount flags.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

security/tomoyo/mount.c

@@ -73,7 +73,7 @@ static bool tomoyo_check_mount_acl(const struct tomoyo_request_info *r,
 }
 
 /**
- * tomoyo_mount_acl2 - Check permission for mount() operation.
+ * tomoyo_mount_acl - Check permission for mount() operation.
  *
  * @r:        Pointer to "struct tomoyo_request_info".
  * @dev_name: Name of device file.
@@ -85,8 +85,8 @@ static bool tomoyo_check_mount_acl(const struct tomoyo_request_info *r,
  *
  * Caller holds tomoyo_read_lock().
  */
-static int tomoyo_mount_acl2(struct tomoyo_request_info *r, char *dev_name,
-			     struct path *dir, char *type, unsigned long flags)
+static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
+			    struct path *dir, char *type, unsigned long flags)
 {
 	struct path path;
 	struct file_system_type *fstype = NULL;
@@ -178,94 +178,6 @@ static int tomoyo_mount_acl2(struct tomoyo_request_info *r, char *dev_name,
 	return error;
 }
 
-/**
- * tomoyo_mount_acl - Check permission for mount() operation.
- *
- * @r:        Pointer to "struct tomoyo_request_info".
- * @dev_name: Name of device file.
- * @dir:      Pointer to "struct path".
- * @type:     Name of filesystem type.
- * @flags:    Mount options.
- *
- * Returns 0 on success, negative value otherwise.
- *
- * Caller holds tomoyo_read_lock().
- */
-static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
-			    struct path *dir, char *type, unsigned long flags)
-{
-	int error;
-	error = -EPERM;
-	if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
-		flags &= ~MS_MGC_MSK;
-	switch (flags & (MS_REMOUNT | MS_MOVE | MS_BIND)) {
-	case MS_REMOUNT:
-	case MS_MOVE:
-	case MS_BIND:
-	case 0:
-		break;
-	default:
-		printk(KERN_WARNING "ERROR: "
-		       "%s%s%sare given for single mount operation.\n",
-		       flags & MS_REMOUNT ? "'remount' " : "",
-		       flags & MS_MOVE    ? "'move' " : "",
-		       flags & MS_BIND    ? "'bind' " : "");
-		return -EINVAL;
-	}
-	switch (flags & (MS_UNBINDABLE | MS_PRIVATE | MS_SLAVE | MS_SHARED)) {
-	case MS_UNBINDABLE:
-	case MS_PRIVATE:
-	case MS_SLAVE:
-	case MS_SHARED:
-	case 0:
-		break;
-	default:
-		printk(KERN_WARNING "ERROR: "
-		       "%s%s%s%sare given for single mount operation.\n",
-		       flags & MS_UNBINDABLE ? "'unbindable' " : "",
-		       flags & MS_PRIVATE    ? "'private' " : "",
-		       flags & MS_SLAVE      ? "'slave' " : "",
-		       flags & MS_SHARED     ? "'shared' " : "");
-		return -EINVAL;
-	}
-	if (flags & MS_REMOUNT)
-		error = tomoyo_mount_acl(r, dev_name, dir,
-				      TOMOYO_MOUNT_REMOUNT_KEYWORD,
-				      flags & ~MS_REMOUNT);
-	else if (flags & MS_MOVE)
-		error = tomoyo_mount_acl(r, dev_name, dir,
-				      TOMOYO_MOUNT_MOVE_KEYWORD,
-				      flags & ~MS_MOVE);
-	else if (flags & MS_BIND)
-		error = tomoyo_mount_acl(r, dev_name, dir,
-				      TOMOYO_MOUNT_BIND_KEYWORD,
-				      flags & ~MS_BIND);
-	else if (flags & MS_UNBINDABLE)
-		error = tomoyo_mount_acl(r, dev_name, dir,
-				      TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD,
-				      flags & ~MS_UNBINDABLE);
-	else if (flags & MS_PRIVATE)
-		error = tomoyo_mount_acl(r, dev_name, dir,
-				      TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD,
-				      flags & ~MS_PRIVATE);
-	else if (flags & MS_SLAVE)
-		error = tomoyo_mount_acl(r, dev_name, dir,
-				      TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD,
-				      flags & ~MS_SLAVE);
-	else if (flags & MS_SHARED)
-		error = tomoyo_mount_acl(r, dev_name, dir,
-				      TOMOYO_MOUNT_MAKE_SHARED_KEYWORD,
-				      flags & ~MS_SHARED);
-	else
-		do {
-			error = tomoyo_mount_acl2(r, dev_name, dir, type,
-						  flags);
-		} while (error == TOMOYO_RETRY_REQUEST);
-	if (r->mode != TOMOYO_CONFIG_ENFORCING)
-		error = 0;
-	return error;
-}
-
 /**
  * tomoyo_mount_permission - Check permission for mount() operation.
  *
@@ -287,6 +199,36 @@ int tomoyo_mount_permission(char *dev_name, struct path *path, char *type,
 	if (tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_MOUNT)
 	    == TOMOYO_CONFIG_DISABLED)
 		return 0;
+	if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
+		flags &= ~MS_MGC_MSK;
+	if (flags & MS_REMOUNT) {
+		type = TOMOYO_MOUNT_REMOUNT_KEYWORD;
+		flags &= ~MS_REMOUNT;
+	}
+	if (flags & MS_MOVE) {
+		type = TOMOYO_MOUNT_MOVE_KEYWORD;
+		flags &= ~MS_MOVE;
+	}
+	if (flags & MS_BIND) {
+		type = TOMOYO_MOUNT_BIND_KEYWORD;
+		flags &= ~MS_BIND;
+	}
+	if (flags & MS_UNBINDABLE) {
+		type = TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD;
+		flags &= ~MS_UNBINDABLE;
+	}
+	if (flags & MS_PRIVATE) {
+		type = TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD;
+		flags &= ~MS_PRIVATE;
+	}
+	if (flags & MS_SLAVE) {
+		type = TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD;
+		flags &= ~MS_SLAVE;
+	}
+	if (flags & MS_SHARED) {
+		type = TOMOYO_MOUNT_MAKE_SHARED_KEYWORD;
+		flags &= ~MS_SHARED;
+	}
 	if (!type)
 		type = "<NULL>";
 	idx = tomoyo_read_lock();