From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Pawelczyk Subject: Re: [PATCH review 09/19] mnt: Fail collect_mounts when applied to unmounted mounts Date: Fri, 03 Apr 2015 10:55:53 +0200 Message-ID: <1428051353.1924.2.camel@samsung.com> References: <87a8yqou41.fsf_-_@x220.int.ebiederm.org> <1428026183-14879-9-git-send-email-ebiederm@xmission.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Linux Containers , Andrey Vagin , Richard Weinberger , Andy Lutomirski , Al Viro , linux-fsdevel@vger.kernel.org, Jann Horn , Omar Sandoval , Willy Tarreau To: "Eric W. Biederman" Return-path: Received: from mailout2.w1.samsung.com ([210.118.77.12]:21384 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752397AbbDCIz5 (ORCPT ); Fri, 3 Apr 2015 04:55:57 -0400 Received: from eucpsbgm2.samsung.com (unknown [203.254.199.245]) by mailout2.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NM800FQF3NTIB90@mailout2.w1.samsung.com> for linux-fsdevel@vger.kernel.org; Fri, 03 Apr 2015 09:59:53 +0100 (BST) In-reply-to: <1428026183-14879-9-git-send-email-ebiederm@xmission.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On czw, 2015-04-02 at 20:56 -0500, Eric W. Biederman wrote: > The only users of collect_mounts are in audit_tree.c > > In audit_tree_trees and audit_add_tree rule the path passed into I think you meant audit_trim_trees. Also you missed a _ in audit_add_tree_rule. > collect_mounts is generated from kern_path passed an audit_tree > pathname which is guaranteed to be an absolute path. In those cases > collect_mounts is obviously intended to work on mounted paths and > if a race results in paths that are unmounted when collect_mounts > it is reasonable to fail early. > > The paths passed into audit_tag_tree don't have the absolute path > check. But are used to play with fsnotify and otherwise interact with > the audit_trees, so again operating only on mounted paths appears > reasonable. > > Avoid having to worry about what happens when we try and audit > unmounted filesystems by restricting collect_mounts to mounts > that appear in the mount tree. > > Signed-off-by: "Eric W. Biederman" > --- > fs/namespace.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/fs/namespace.c b/fs/namespace.c > index 2b12b7a9455d..acc5583764dc 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -1669,8 +1669,11 @@ struct vfsmount *collect_mounts(struct path *path) > { > struct mount *tree; > namespace_lock(); > - tree = copy_tree(real_mount(path->mnt), path->dentry, > - CL_COPY_ALL | CL_PRIVATE); > + if (!check_mnt(real_mount(path->mnt))) > + tree = ERR_PTR(-EINVAL); > + else > + tree = copy_tree(real_mount(path->mnt), path->dentry, > + CL_COPY_ALL | CL_PRIVATE); > namespace_unlock(); > if (IS_ERR(tree)) > return ERR_CAST(tree); -- Lukasz Pawelczyk Samsung R&D Institute Poland Samsung Electronics