Date: Wed, 25 May 2011 10:28:17 -0500
From: Serge Hallyn <serge.hallyn@canonical.com>
To: Robert =?utf-8?B?xZp3acSZY2tp?= <robert@swiecki.net>
Cc: Eugene Teo <eugeneteo@kernel.sg>, linux-kernel@vger.kernel.org,
        security@kernel.org, kees@ubuntu.com,
        Tavis Ormandy <taviso@cmpxchg8b.com>,
        David Howells <dhowells@redhat.com>
Subject: Re: [Security] Fwd: Oops (bad memory deref) in slab_alloc() due to
 filp_cachep holding incorrect values
Message-ID: <20110525152817.GC3507@mail.hallyn.com>
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Quoting Robert Święcki (robert@swiecki.net):
> >> Given that it doesn't seem to appear in 2.6.39-rc4, and judging by the
> >> names of functions involved, this change looks suspiciously related to
> >> this oops (even if it just made the keyctl problem visible)
> >> http://git.itanic.dy.fi/?p=linux-stable;a=commitdiff;h=47a150edc2ae734c0f4bf50aa19499e23b9a46f8
> >>
> >> >> #include <sys/stat.h>
> >> >> #include <sys/wait.h>
> >> >> #include <unistd.h>
> >> >> #include <sys/syscall.h>
> >> >> #include <linux/keyctl.h>
> >> >> #include <linux/sched.h>
> >> >>
> >> >> int TH1(void *dummy) {
> >> >>        syscall(__NR_keyctl, KEYCTL_SESSION_TO_PARENT);
> >
> > Thanks!
> >
> > Fooi, it looks like all users of cred_alloc_blank() may need to be
> > audited wrt commit 47a150edc2ae734c0f4bf50aa19499e23b9a46f8.
> >
> > Does this fix the bug you're seeing?
> 
> Yup, the kernel survives both the testcase and a short syscall fuzzing
> session. Thanks.

Thanks, Robert.

David, assuming this gets your ack, do you mind pushing this one forward?

thanks,
-serge
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