oss-security - Re: CVE request: kernel: tc: uninitialised kernel memory leak

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Message-ID: <20090906203350.GH9125@1wt.eu>
Date: Sun, 6 Sep 2009 22:33:51 +0200
From: Willy Tarreau <w@....eu>
To: Solar Designer <solar@...nwall.com>
Cc: oss-security@...ts.openwall.com
Subject: Re: CVE request: kernel: tc: uninitialised kernel memory leak

Hi Alexander,

On Sat, Sep 05, 2009 at 09:52:50PM +0400, Solar Designer wrote:
> On Thu, Sep 03, 2009 at 11:45:03AM +0800, Eugene Teo wrote:
> > Three bytes of uninitialised kernel memory are currently leaked to user.
> > 
> > http://patchwork.ozlabs.org/patch/32830/
> > https://bugzilla.redhat.com/show_bug.cgi?id=520990
> 
> 2.4 kernels appear to be affected as well, and moreover they appear to
> require at least some of these older fixes as well:
> 
> http://marc.info/?l=git-commits-head&m=112002138324380

Thanks for letting me know.

I'm late on fixes these days. I still have several ones to apply but
need to find time to work on them.

> Specifically, in net/sched/sch_api.c both tc_fill_qdisc() and
> tc_fill_tclass() are affected - the former was fixed in 2.6 in 2005,
> the latter is being fixed now.
> 
> I'm not sure what this means for CVE.  Should there be another CVE id
> for the issues fixed in 2.6 in 2005 (if one was not allocated at the
> time), and 2.4 could reference both CVE ids now?

Personally I have no problem referencing an old CVE in a recent
commit if it helps tracking common bugs. And I think we've already
done that in the past.

> I did not check if any of the affected code is possibly normally only
> available to root, but even if so the issue may be relevant on systems
> with containers.

In general I tend to consider those "bytes leak" bugs with lower
importance, but they need to be fixed anyway since they may eventually
impact some random setup somewhere.

Thanks,
Willy

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