From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751701Ab3LKVE4 (ORCPT ); Wed, 11 Dec 2013 16:04:56 -0500 Received: from mail-qc0-f180.google.com ([209.85.216.180]:50666 "EHLO mail-qc0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453Ab3LKVDJ (ORCPT ); Wed, 11 Dec 2013 16:03:09 -0500 From: Tejun Heo To: gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, ebiederm@xmission.com, kay@vrfy.org, Tejun Heo Subject: [PATCH 2/6] kernfs: add REMOVED check to create and rename paths Date: Wed, 11 Dec 2013 16:02:56 -0500 Message-Id: <1386795780-23324-3-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.8.4.2 In-Reply-To: <1386795780-23324-1-git-send-email-tj@kernel.org> References: <1386795780-23324-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org kernfs currently assumes that the caller doesn't try to create a new node under a removed parent, rename a removed node, or move a node under a removed node. While this works fine for sysfs, it'd be nice to have protection against such cases especially given that kernfs is planned to add support for mkdir, rmdir and rename requsts from userland which may make race conditions more likely. This patch updates create and rename paths to check REMOVED and fail the operation with -ENOENT if performed on or towards removed nodes. Note that remove path already has such check. Signed-off-by: Tejun Heo --- fs/kernfs/dir.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index e55bb02..ba5f372 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -430,6 +430,9 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn, if (kernfs_type(parent) != KERNFS_DIR) return -EINVAL; + if (parent->flags & KERNFS_REMOVED) + return -ENOENT; + kn->hash = kernfs_name_hash(kn->name, kn->ns); kn->parent = parent; kernfs_get(parent); @@ -863,6 +866,10 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, mutex_lock(&kernfs_mutex); + error = -ENOENT; + if ((kn->flags | new_parent->flags) & KERNFS_REMOVED) + goto out; + error = 0; if ((kn->parent == new_parent) && (kn->ns == new_ns) && (strcmp(kn->name, new_name) == 0)) -- 1.8.4.2