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Date:      Tue, 26 Apr 2016 17:18:04 -0400
From:      Shawn Webb <shawn.webb@hardenedbsd.org>
To:        Kristof Provost <kp@FreeBSD.org>
Cc:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   Re: svn commit: r298664 - head/sys/fs/msdosfs
Message-ID:  <20160426211804.GB13055@mutt-hardenedbsd>
In-Reply-To: <2190C480-1B7A-47F8-BFB4-D7C8E6F25385@FreeBSD.org>
References:  <201604262036.u3QKaWto038435@repo.freebsd.org> <20160426210138.GA13055@mutt-hardenedbsd> <2190C480-1B7A-47F8-BFB4-D7C8E6F25385@FreeBSD.org>

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[-- Attachment #1 --]
On Tue, Apr 26, 2016 at 11:05:38PM +0200, Kristof Provost wrote:
> 
> > On 26 Apr 2016, at 23:01, Shawn Webb <shawn.webb@hardenedbsd.org> wrote:
> > 
> > On Tue, Apr 26, 2016 at 08:36:32PM +0000, Kristof Provost wrote:
> >> Author: kp
> >> Date: Tue Apr 26 20:36:32 2016
> >> New Revision: 298664
> >> URL: https://svnweb.freebsd.org/changeset/base/298664
> >> 
> >> Log:
> >>  msdosfs: Prevent buffer overflow when expanding win95 names
> >> 
> >>  In win2unixfn() we expand Windows 95 style long names. In some cases that
> >>  requires moving the data in the nbp->nb_buf buffer backwards to make room. That
> >>  code failed to check for overflows, leading to a stack overflow in win2unixfn().
> >> 
> >>  We now check for this event, and mark the entire conversion as failed in that
> >>  case. This means we present the 8 character, dos style, name instead.
> >> 
> >>  PR: 204643
> >>  Differential Revision:	https://reviews.freebsd.org/D6015
> > 
> > Will this be MFC'd? Since it's triggerable as non-root, should this have
> > a CVE? Though the commit log shows technical comments, it doesn't show
> > related security information.
> 
> Yes, I???ll put MFCing this on my todo list.
> 
> I have to admit that I???ve not given the security implications much thought. The bug has always been caught by the stack canary on my test systems, without that it could potentially be quite dangerous.
> (Given constraints of having to be able to mount arbitrary file systems as non-root of course.)
> 
> Regards,
> Kristof

Was secteam@ even involved, then? Seems like a user-facing kernel buffer
overflow ought to have involved secteam@.

Also, the differential revision link you posted is incorrect.

Thanks,

-- 
Shawn Webb
HardenedBSD

GPG Key ID:          0x6A84658F52456EEE
GPG Key Fingerprint: 2ABA B6BD EF6A F486 BE89  3D9E 6A84 658F 5245 6EEE

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