linux-kernel - Re: [PATCH] vfs: automount should ignore LOOKUP

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]

Message-ID: <20110908195043.GV2203@ZenIV.linux.org.uk>
Date:	Thu, 8 Sep 2011 20:50:43 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Miklos Szeredi <miklos@...redi.hu>, Ian Kent <raven@...maw.net>,
	David Howells <dhowells@...hat.com>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	Leonardo Chiquitto <leonardo.lists@...il.com>,
	autofs@...ux.kernel.org
Subject: Re: [PATCH] vfs: automount should ignore LOOKUP_FOLLOW

On Thu, Sep 08, 2011 at 10:42:28AM -0700, Linus Torvalds wrote:

> > You say it's a step in the right direction but I don't see why. ?Either
> > we want stat *and* lstat to both be correct and trigger the automount or
> > we are satisfied with the incorrect but well established practice of not
> > triggering on (l)stat.
> >
> > The middle ground makes no sense IMO, there's nothing gained by the
> > differentiated behavior based on LOOKUP_FOLLOW.
> >
> > Can you explain why it's better if stat() tiggers automounts and gives a
> > correct result but lstat() doesn't?
> 
> I have to say that this is a very cogent question.
> 
> The one thing I've not seen in the thread yet is a description of the
> failure. What does the regression look like? Just "very slow 'ls' with
> some versions of 'ls'" or what?
> 
> I'm inclined to apply the patch as a regression fix, but I'll let this
> thread try to convince me for another day..

IIRC, that matches traditional SunOS behaviour and it actually does make
sense; you want wildcard expansion and ls -l to be doable even when there's
a stuck NFS server.  IOW, non-triggering lstat(2) is a matter of usability...
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/