From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?UTF-8?Q?Court=C3=A8s?=)
Subject: bug#27437: Source downloader accepts X.509 certificate for incorrect
	domain
Date: Thu, 22 Jun 2017 09:57:23 +0200
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References: <20170621061752.GA32412@jasmine.lan> <87lgolipi0.fsf@gnu.org>
	<20170622040901.GA8700@jasmine.lan>
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To: Leo Famulari <leo@famulari.name>
Cc: 27437@debbugs.gnu.org

Leo Famulari <leo@famulari.name> skribis:

> On Wed, Jun 21, 2017 at 12:50:15PM +0200, Ludovic Court=C3=A8s wrote:
>> Leo Famulari <leo@famulari.name> skribis:
>> > While working on some package updates, I found that the source code
>> > downloader will accept an X.509 certificate for an incorrect site.
>
> [...]
>
>> IOW, since we=E2=80=99re checking the integrity of the tarball anyway, a=
nd we
>> assume developers checked its authenticity when writing the recipe, then
>> who cares whether downloads.xiph.org has a valid certificate?
>>=20
>> Does it make sense?
>
> Yeah, I think it makes sense if checking the certificates would add too
> much complexity for what I think is a minor benefit: protecting against
> exploitation of bugs by MITM (but not xiph.org) in whatever code runs
> after the connection is initiated and before the hash is calculated.
>
> Perhaps a MITM could send a huge file and fill up the disk or something
> like that.

I=E2=80=99m generally in favor of relying on X.509 certificates as little as
possible, and in this case, while I agree that it could protect us
against the scenario you describe, I think it=E2=80=99s a bit of a stretch.

However, we=E2=80=99d very likely have bug reports of people for which down=
loads
fail because of various issues in the X.509 infrastructure and/or in how
the they set up their system (=E2=80=98nss-certs=E2=80=99 uninstalled or to=
o old,
SSL_CERT_DIR unset, etc.)

Thoughts?

Thanks,
Ludo=E2=80=99.