linux-kernel - Re: request for patches: showing mount options

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 30 Jul 2007 11:20:34 -0400
From:	Chuck Lever <chuck.lever@...cle.com>
To:	Miklos Szeredi <miklos@...redi.hu>
CC:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org, kzak@...hat.com, ericvh@...il.com,
	lucho@...kov.net, zippel@...ux-m68k.org, hpa@...or.com,
	raven@...maw.net, rathamahata@...4.ru, dhowells@...hat.com,
	sfrench@...ba.org, mhalcrow@...ibm.com,
	phillip@...lewell.homeip.net, hirofumi@...l.parknet.co.jp,
	mikulas@...ax.karlin.mff.cuni.cz, wli@...omorphy.com,
	shaggy@...tin.ibm.com, vandrove@...cvut.cz,
	trond.myklebust@....uio.no, aia21@...tab.net,
	mark.fasheh@...cle.com, kurt.hackel@...cle.com,
	reiserfs-devel@...r.kernel.org, bfennema@...con.csc.calpoly.edu,
	dushistov@...l.ru, xfs-masters@....sgi.com, arnd@...db.de,
	holzheu@...ibm.com
Subject: Re: request for patches: showing mount options

Miklos Szeredi wrote:
>>>> Some mount options are never passed to the kernel, and thus can't appear 
>>>> in /proc/mounts.  Examples include user, users, and _netdev for NFS.
>>> These options control *who* may mount and *when* to mount.  They are
>>> not a property of the mount itself and are not added to /etc/mtab.
>>>
>>> There's a "user=ID" option that is added to /etc/mtab in case of user
>>> mounts.  This identifies the owner of the mount, so that it can be
>>> unmounted by that user.  There are patches in -mm that enable the
>>> kernel to store this info.
>>>
>>> Do you have other examples in mind?

There are a few more cases for NFS mount.

After a successful mount, the NFS mount command tucks some options into 
/etc/mtab that reflect which mountd was used for the mount, and what 
protocol version and port was used for the mount request.  Those options 
are not passed to the kernel, and do not appear in /proc/mounts today. 
See nfs(5)'s discussion of the mountport, mounthost, mountprog, and 
mountvers options.

However, the trend for NFS is to push mount option parsing into the 
kernel.  Thus all options will be passed to the kernel, and at that 
point it should be able to reflect the mount* options in /proc/mounts. 
But it doesn't do that quite yet.

I'm wondering if there are other such cases in other file systems.

View attachment "chuck.lever.vcf" of type "text/x-vcard" (291 bytes)