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From: Brian Foster <bfoster@redhat.com>
To: Ben Myers <bpm@sgi.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 7/9] xfs: kill suid/sgid through the truncate path.
Date: Thu, 30 May 2013 12:02:40 -0400	[thread overview]
Message-ID: <51A77820.2070804@redhat.com> (raw)
In-Reply-To: <20130530155208.GD20028@sgi.com>

On 05/30/2013 11:52 AM, Ben Myers wrote:
> Hey Brian,
> 
> On Thu, May 30, 2013 at 10:17:30AM -0400, Brian Foster wrote:
>> On 05/27/2013 02:38 AM, Dave Chinner wrote:
>>> From: Dave Chinner <dchinner@redhat.com>
>>>
>>> XFS has failed to kill suid/sgid bits correctly when truncating
>>> files of non-zero size since commit c4ed4243 ("xfs: split
>>> xfs_setattr") introduced in the 3.1 kernel. Fix it.
>>>
>>
>> The code makes sense and I can easily hit an assert when truncating
>> (extending) a suid file on a debug kernel without this patch (and I see
>> the suid dropped with the patch).
> 
> What commands did you use?  It seems like this is dealing with S_ISGID, correct?
> 

Hi Ben,

Yeah, that confused me at first as well. I believe the vfs interprets
the ATTR_KILL_SUID/SGIT bits prior to the setattr call and wipes out the
associated mode bits if necessary.

What I did was basically create a zero sized file as root, chmod to a+s
and a+rwx and then as a regular user, truncate that file to something
larger than zero. Without the patch I hit the assert and with the patch
the assert doesn't fire and the setuid bit is dropped.

Brian

> Thanks,
> 	Ben
> 

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  reply	other threads:[~2013-05-30 16:05 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-27  6:38 [PATH 0/9] xfs: fixes for 3.10-rc4 Dave Chinner
2013-05-27  6:38 ` [PATCH 1/9] xfs: don't emit v5 superblock warnings on write Dave Chinner
2013-05-29 16:39   ` Brian Foster
2013-05-30 17:49     ` Ben Myers
2013-06-11  6:05       ` Dave Chinner
2013-06-11 21:29         ` Ben Myers
2013-05-27  6:38 ` [PATCH 2/9] xfs: fix incorrect remote symlink block count Dave Chinner
2013-05-29 16:39   ` Brian Foster
2013-05-30  0:46     ` Dave Chinner
2013-05-30 17:49     ` Ben Myers
2013-05-27  6:38 ` [PATCH 3/9] xfs: increase number of ACL entries for V5 superblocks Dave Chinner
2013-05-29 16:40   ` Brian Foster
2013-05-27  6:38 ` [PATCH 4/9] xfs: rework dquot CRCs Dave Chinner
2013-05-29 18:58   ` Brian Foster
2013-05-30  1:00     ` Dave Chinner
2013-05-30 12:02       ` Brian Foster
2013-06-03  4:12         ` Dave Chinner
2013-05-27  6:38 ` [PATCH 5/9] xfs: fix split buffer vector log recovery support Dave Chinner
2013-05-29 19:21   ` Mark Tinguely
2013-05-30 17:49     ` Ben Myers
2013-05-27  6:38 ` [PATCH 6/9] xfs: disable swap extents ioctl on CRC enabled filesystems Dave Chinner
2013-05-28 21:49   ` Ben Myers
2013-05-30  1:07     ` Dave Chinner
2013-05-29 21:06   ` Brian Foster
2013-05-30 17:56     ` Ben Myers
2013-05-27  6:38 ` [PATCH 7/9] xfs: kill suid/sgid through the truncate path Dave Chinner
2013-05-30 14:17   ` Brian Foster
2013-05-30 15:52     ` Ben Myers
2013-05-30 16:02       ` Brian Foster [this message]
2013-05-30 17:07         ` Ben Myers
2013-05-27  6:38 ` [PATCH 8/9] xfs: add fsgeom flag for v5 superblock support Dave Chinner
2013-05-29 15:10   ` Eric Sandeen
2013-05-29 21:43     ` Ben Myers
2013-05-29 21:47       ` Ben Myers
2013-05-30  1:28       ` Dave Chinner
2013-05-30  1:11     ` Dave Chinner
2013-05-30 14:17   ` Brian Foster
2013-05-30 17:57     ` Ben Myers
2013-05-27  6:38 ` [PATCH 9/9] xfs: inode unlinked list needs to recalculate the inode CRC Dave Chinner
2013-05-28 11:51   ` Dave Chinner
2013-05-28 20:36   ` [PATCH 9a,9b v2, replacements] xfs: unlinked list crcs Dave Chinner
2013-05-28 20:36     ` [PATCH 1/2] xfs: fix log recovery transaction item reordering Dave Chinner
2013-05-28 20:36     ` [PATCH 2/2] xfs: inode unlinked list needs to recalculate the inode CRC Dave Chinner
2013-05-30 14:17       ` Brian Foster
2013-05-30 20:27         ` Dave Chinner
2013-05-28  8:37 ` [PATCH 10/9] xfs: fix dir3 freespace block corruption Dave Chinner
2013-05-30 19:15   ` Ben Myers
2013-05-31 21:54     ` Ben Myers
2013-05-28 17:56 ` [PATH 0/9] xfs: fixes for 3.10-rc4 Ben Myers
2013-05-28 23:54   ` Dave Chinner
2013-05-29 19:01     ` Ben Myers
2013-05-29 19:27       ` Eric Sandeen
2013-05-29 19:45         ` Ben Myers
2013-05-28 21:27 ` [PATCH 11/9] xfs: fix remote attribute invalidation for a leaf Dave Chinner

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