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From: "Ludovic Courtès" <ludovic.courtes@inria.fr>
To: Simon Tournier <zimon.toutoune@gmail.com>
Cc: 62656@debbugs.gnu.org, Nicolas Graves <ngraves@ngraves.fr>
Subject: bug#62656: broken guix time-machine + software-heritage
Date: Fri, 05 May 2023 09:36:43 +0200	[thread overview]
Message-ID: <87354bp6us.fsf@inria.fr> (raw)
In-Reply-To: <87mt2k821f.fsf@gmail.com> (Simon Tournier's message of "Thu, 04 May 2023 19:00:28 +0200")

Hi!

Simon Tournier <zimon.toutoune@gmail.com> skribis:

> On jeu., 04 mai 2023 at 15:05, Ludovic Courtès <ludovic.courtes@inria.fr> wrote:
>
>>> Well, I do not see which features will be missing.
>>
>> Those mentioned earlier, provenance tracking and downgrade detection in
>> particular.
>
> Do we care about provenance tracking for this scenario?  Similarly, do
> we care about downgrade detection for this scenario?

Provenance tracking, yes.  I wrote about the current status: (guix
describe), (guix channels), etc. expect a full Git repo, which is why
things are done this way.

We could imagine a different design, but that’s a broader endeavor.

[...]

> If tomorrow Savannah is totally down and let assume the malicious Eve is
> serving https://git.savannah.gnu.org/git/guix.git.  The authentication
> is useless since Eve can easily rewrite it.

The authentication mechanism is designed to make this impossible.
That’s why one can run:

  guix pull --url=https://github.com/guix-mirror/guix

without fear (worst that can happen is that the mirror is stale).

> The only mechanism that protects Alice is the commit SHA-1 hash she
> has at hand.  Eve needs to attack this SHA-1 with some collision.  And
> if it’s possible to produce pre-image attack for SHA-1, then nothing
> would prevent Eve to also replace the origins of some packages in
> https://git.savannah.gnu.org/git/guix.git.

True to some extent—see the section about SHA1 in the Programming paper¹.

Ludo’.

¹ https://doi.org/10.22152/programming-journal.org/2023/7/1




  reply	other threads:[~2023-05-05  7:37 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-03 21:39 bug#62656: broken guix time-machine + software-heritage Nicolas Graves via Bug reports for GNU Guix
2023-04-04 10:51 ` Simon Tournier
2023-04-26  9:50 ` Ludovic Courtès
2023-04-26 10:01   ` Ludovic Courtès
2023-10-24 13:23     ` Simon Tournier
2023-04-28 14:43   ` Simon Tournier
2023-05-02  7:42     ` Ludovic Courtès
2023-05-02 18:01       ` Simon Tournier
2023-05-04  7:22         ` Ludovic Courtès
2023-05-04  7:57           ` Simon Tournier
2023-05-04 13:05             ` Ludovic Courtès
2023-05-04 17:00               ` Simon Tournier
2023-05-05  7:36                 ` Ludovic Courtès [this message]
2024-02-04 13:03 ` bug#62656: close 62656 Nicolas Graves via Bug reports for GNU Guix

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