Date: Sun, 29 May 2011 19:23:56 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
        Kees Cook <kees.cook@canonical.com>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
        Peter Zijlstra <peterz@infradead.org>, Will Drewry <wad@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/5] v2 seccomp_filters: Enable ftrace-based system call
 filtering
Message-ID: <20110529182356.GJ11521@ZenIV.linux.org.uk>
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On Sun, May 29, 2011 at 10:02:06AM -0700, Linus Torvalds wrote:

> And yes, it is absolutely acceptable. The only questions in my mind are
> 
>  - why haven't we done this long ago?
> 
>  - do we have the flag space?
> 
>  - should we do a O_NOMNT_PATH flag to do the same for mount-points?
> 
>   Some people worry about being confused by bind mounts etc.
> 
>  - do we think ".." is worthy of a flag too?
> 
>    or is that a "user space can damn well check that itself, even if
> it would be absolutely trivial to check in the kernel too"?
> 
> Whatever. I think the NOFOLLOW_PATH one is pretty much a no-brainer.
> It's not like symlink worries are unusual.

It's not *quite* a no-brainer.  Guys, please hold that one off for a while;
we have more massage to do in the area and I *really* want to get atomic
open work finished (== intents gone, revalidation vs mountpoints sanitized,
etc.) before anything else is done to fs/namie.c.  OK?

And as for .. - userland can bloody well check that on its own if it cares.
Let's keep it simple, please - we already have things far too complicated
in there for my taste.
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