From: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
To: "Gamblin, Todd" <gamblin2@llnl.gov>
Cc: Junio C Hamano <gitster@pobox.com>,
Philip Oakley <philipoakley@iee.email>,
"git@vger.kernel.org" <git@vger.kernel.org>
Subject: Re: Commit SHA1 == SHA1 checksum?
Date: Mon, 7 Feb 2022 17:46:54 -0500 [thread overview]
Message-ID: <20220207224654.aju3rmxcrhapi4d2@meerkat.local> (raw)
In-Reply-To: <8A241137-C8D6-40A6-ABB8-5624B9E617A9@llnl.gov>
On Mon, Feb 07, 2022 at 10:29:37PM +0000, Gamblin, Todd wrote:
> > 2. packagers would be able to perform cryptographic verification without
> > needing to track any extra sources like corresponding .sig files; they
> > would just need to add a build-time dependency on git (plus whatever it
> > calls for cryptographic verification, such as gnupg or openssh)
>
> This is a cool idea, but tar/gzip/etc. are vulnerable to input attacks (or
> at least there have been CVEs in the past), so this does not eliminate the
> need to verify a downloaded .tar or .tar.gz file independently. You can
> verify the contents of the tar, but to do that you have to expand it, and to
> do that you’re still passing untrusted input to tar.
That's not really different from what git does when it clones a remote
repository to run "git verify-tag". It still accepts untrusted input from the
remote server, performs a lot of compression/decompression operations, etc, so
this is not introducing anything that git isn't already required to do.
I know there's a lot to be said about the simplicity of just computing a
signature over file bytes, but there are features you end up sacrificing, such
as ability to provide a single signature for multiple compression types,
adding a better compression algorithm in the future, or simply recompressing
with better flags in a long background process.
My goal is to improve the current situation where we're actually doing pretty
good for signed in-git objects, but none of that is carried over to packaging
systems. The only effort I know in that area is sigstore, but it requires
quite a bit of work to properly use on the part of the project maintainer,
whereas it would be great to be able to say "just do git tag -s and the
packaging systems will be able to use that."
-K
next prev parent reply other threads:[~2022-02-07 22:47 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-05 1:19 Commit SHA1 == SHA1 checksum? Gamblin, Todd
2022-02-06 0:22 ` Philip Oakley
2022-02-06 9:00 ` Gamblin, Todd
2022-02-06 10:23 ` Johannes Sixt
2022-02-06 10:15 ` Junio C Hamano
2022-02-06 19:25 ` Philip Oakley
2022-02-06 20:02 ` Junio C Hamano
2022-02-06 21:33 ` Philip Oakley
2022-02-07 8:15 ` Gamblin, Todd
2022-02-07 13:15 ` Konstantin Ryabitsev
2022-02-07 21:08 ` Gamblin, Todd
2022-02-07 13:32 ` Konstantin Ryabitsev
2022-02-07 20:57 ` Junio C Hamano
2022-02-07 21:34 ` Konstantin Ryabitsev
2022-02-07 22:29 ` Gamblin, Todd
2022-02-07 22:46 ` Konstantin Ryabitsev [this message]
2022-02-08 6:23 ` Gamblin, Todd
2022-02-07 22:49 ` Junio C Hamano
2022-02-07 23:02 ` Konstantin Ryabitsev
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