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From: Greg Kurz <groug@kaod.org>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Prasad J Pandit <prasad@redhat.com>,
	qemu-devel@nongnu.org, Jann Horn <jannh@google.com>
Subject: Re: [Qemu-devel] [PATCH 04/29] 9pfs: introduce openat_nofollow() helper
Date: Mon, 27 Feb 2017 11:37:43 +0100	[thread overview]
Message-ID: <20170227113743.0920003b@bahia.lan> (raw)
In-Reply-To: <20170227102058.GC28403@stefanha-x1.localdomain>

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On Mon, 27 Feb 2017 10:20:58 +0000
Stefan Hajnoczi <stefanha@gmail.com> wrote:

> On Fri, Feb 24, 2017 at 11:17:44PM +0100, Greg Kurz wrote:
> > On Fri, 24 Feb 2017 17:17:30 +0000
> > Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > [...]  
> > > > > This function doesn't handle absolute paths?  It ignores leading '/' and
> > > > > therefore treats all paths as relative paths.
> > > > >     
> > > > 
> > > > Yes because any path coming from the client is supposed (*) to be relative to the
> > > > shared directory and openat(2) says:    
> > > 
> > > Please change the function name since this isn't openat with nofollow
> > > behavior, it's a subset of openat that only takes relative paths with
> > > nofollow behavior.  
> > 
> > In the v2, this function is only called by local_open_nofollow() actually.
> > Maybe I should move the stripping of leading '/' characters there ?  
> 
> As long as the function name is clear then I'm happy.  If it has
> different semantics from openat() then it should have a different name
> (e.g. relative_openat_nofollow()).
> 

I've moved the stripping to the caller. This makes the code simpler.

> Stefan


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  reply	other threads:[~2017-02-27 10:38 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-20 14:39 [Qemu-devel] [PATCH 00/29] 9pfs: local: fix vulnerability to symlink attacks Greg Kurz
2017-02-20 14:39 ` [Qemu-devel] [PATCH 01/29] 9pfs: local: move xattr security ops to 9p-xattr.c Greg Kurz
2017-02-23 10:57   ` Stefan Hajnoczi
2017-02-20 14:39 ` [Qemu-devel] [PATCH 02/29] 9pfs: remove side-effects in local_init() Greg Kurz
2017-02-23 11:00   ` Stefan Hajnoczi
2017-02-20 14:39 ` [Qemu-devel] [PATCH 03/29] 9pfs: remove side-effects in local_open() and local_opendir() Greg Kurz
2017-02-23 11:01   ` Stefan Hajnoczi
2017-02-20 14:39 ` [Qemu-devel] [PATCH 04/29] 9pfs: introduce openat_nofollow() helper Greg Kurz
2017-02-23 11:16   ` Stefan Hajnoczi
2017-02-23 11:56     ` Greg Kurz
2017-02-24 17:17       ` Stefan Hajnoczi
2017-02-24 22:17         ` Greg Kurz
2017-02-27 10:20           ` Stefan Hajnoczi
2017-02-27 10:37             ` Greg Kurz [this message]
2017-02-20 14:39 ` [Qemu-devel] [PATCH 05/29] 9pfs: local: keep a file descriptor on the shared folder Greg Kurz
2017-02-23 11:23   ` Stefan Hajnoczi
2017-02-20 14:40 ` [Qemu-devel] [PATCH 06/29] 9pfs: local: open/opendir: don't follow symlinks Greg Kurz
2017-02-23 13:18   ` Stefan Hajnoczi
2017-02-20 14:40 ` [Qemu-devel] [PATCH 07/29] 9pfs: local: introduce symlink-attack safe xattr helpers Greg Kurz
2017-02-23 13:44   ` Stefan Hajnoczi
2017-02-23 20:54     ` Greg Kurz
2017-02-23 15:02   ` Eric Blake
2017-02-23 15:05     ` Jann Horn
2017-02-23 20:31       ` Greg Kurz
2017-02-23 21:01     ` Greg Kurz
2017-02-20 14:40 ` [Qemu-devel] [PATCH 08/29] 9pfs: local: lgetxattr: don't follow symlinks Greg Kurz
2017-02-23 13:45   ` Stefan Hajnoczi
2017-02-20 14:40 ` [Qemu-devel] [PATCH 09/29] 9pfs: local: llistxattr: " Greg Kurz
2017-02-23 14:07   ` Stefan Hajnoczi
2017-02-20 14:40 ` [Qemu-devel] [PATCH 10/29] 9pfs: local: lsetxattr: " Greg Kurz
2017-02-23 14:08   ` Stefan Hajnoczi
2017-02-20 14:40 ` [Qemu-devel] [PATCH 11/29] 9pfs: local: lremovexattr: " Greg Kurz
2017-02-23 14:09   ` Stefan Hajnoczi
2017-02-24 21:58   ` Greg Kurz
2017-02-20 14:40 ` [Qemu-devel] [PATCH 12/29] 9pfs: local: unlinkat: " Greg Kurz
2017-02-23 14:17   ` Stefan Hajnoczi
2017-02-20 14:41 ` [Qemu-devel] [PATCH 13/29] 9pfs: local: remove: " Greg Kurz
2017-02-23 14:23   ` Stefan Hajnoczi
2017-02-24  0:21     ` Greg Kurz
2017-02-20 14:41 ` [Qemu-devel] [PATCH 14/29] 9pfs: local: utimensat: " Greg Kurz
2017-02-23 14:48   ` Stefan Hajnoczi
2017-02-20 14:41 ` [Qemu-devel] [PATCH 15/29] 9pfs: local: statfs: " Greg Kurz
2017-02-23 14:48   ` Stefan Hajnoczi
2017-02-20 14:41 ` [Qemu-devel] [PATCH 16/29] 9pfs: local: truncate: " Greg Kurz
2017-02-23 14:50   ` Stefan Hajnoczi
2017-02-20 14:41 ` [Qemu-devel] [PATCH 17/29] 9pfs: local: readlink: " Greg Kurz
2017-02-23 14:52   ` Stefan Hajnoczi
2017-02-20 14:41 ` [Qemu-devel] [PATCH 18/29] 9pfs: local: lstat: " Greg Kurz
2017-02-23 14:55   ` Stefan Hajnoczi
2017-02-20 14:41 ` [Qemu-devel] [PATCH 19/29] 9pfs: local: renameat: " Greg Kurz
2017-02-23 14:57   ` Stefan Hajnoczi
2017-02-20 14:41 ` [Qemu-devel] [PATCH 20/29] 9pfs: local: rename: use renameat Greg Kurz
2017-02-23 14:57   ` Stefan Hajnoczi
2017-02-20 14:42 ` [Qemu-devel] [PATCH 21/29] 9pfs: local: improve error handling in link op Greg Kurz
2017-02-23 15:00   ` Stefan Hajnoczi
2017-02-20 14:42 ` [Qemu-devel] [PATCH 22/29] 9pfs: local: link: don't follow symlinks Greg Kurz
2017-02-23 15:01   ` Stefan Hajnoczi
2017-02-20 14:42 ` [Qemu-devel] [PATCH 23/29] 9pfs: local: chmod: " Greg Kurz
2017-02-23 15:10   ` Stefan Hajnoczi
2017-02-24 10:34     ` Greg Kurz
2017-02-24 15:23       ` Eric Blake
2017-02-24 16:22         ` Jann Horn
2017-02-24 19:25           ` Greg Kurz
2017-02-20 14:42 ` [Qemu-devel] [PATCH 24/29] 9pfs: local: chown: " Greg Kurz
2017-02-23 15:10   ` Stefan Hajnoczi
2017-02-20 14:42 ` [Qemu-devel] [PATCH 25/29] 9pfs: local: symlink: " Greg Kurz
2017-02-23 15:15   ` Stefan Hajnoczi
2017-02-20 14:42 ` [Qemu-devel] [PATCH 26/29] 9pfs: local: mknod: " Greg Kurz
2017-02-23 15:16   ` Stefan Hajnoczi
2017-02-20 14:42 ` [Qemu-devel] [PATCH 27/29] 9pfs: local: mkdir: " Greg Kurz
2017-02-23 15:16   ` Stefan Hajnoczi
2017-02-20 14:42 ` [Qemu-devel] [PATCH 28/29] 9pfs: local: open2: " Greg Kurz
2017-02-23 15:22   ` Stefan Hajnoczi
2017-02-20 14:43 ` [Qemu-devel] [PATCH 29/29] 9pfs: local: drop unused code Greg Kurz
2017-02-23 15:22   ` Stefan Hajnoczi

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