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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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On Tue, Apr 26, 2016 at 11:05:38PM +0200, Kristof Provost wrote:
>=20
> > On 26 Apr 2016, at 23:01, Shawn Webb <shawn.webb@hardenedbsd.org> wrote:
> >=20
> > 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
> >>=20
> >> Log:
> >>  msdosfs: Prevent buffer overflow when expanding win95 names
> >>=20
> >>  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 wi=
n2unixfn().
> >>=20
> >>  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.
> >>=20
> >>  PR: 204643
> >>  Differential Revision:	https://reviews.freebsd.org/D6015
> >=20
> > 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.
>=20
> Yes, I???ll put MFCing this on my todo list.
>=20
> I have to admit that I???ve not given the security implications much thou=
ght. 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 a=
s non-root of course.)
>=20
> 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,

--=20
Shawn Webb
HardenedBSD

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

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