From: "Ludovic Courtès" <ludo@gnu.org>
To: zimoun <zimon.toutoune@gmail.com>
Cc: 44187-done@debbugs.gnu.org
Subject: bug#44187: Channel clones lack SWH fallback
Date: Wed, 22 Sep 2021 12:03:32 +0200 [thread overview]
Message-ID: <87fstxhqq3.fsf@gnu.org> (raw)
In-Reply-To: <CAJ3okZ2XNXecc-Q0xCGcmJk99kJvk0coHSp+zpUwRGwbJSdOhg@mail.gmail.com> (zimoun's message of "Mon, 20 Sep 2021 11:27:32 +0200")
Hi,
zimoun <zimon.toutoune@gmail.com> skribis:
> On Sat, 18 Sept 2021 at 23:10, Ludovic Courtès <ludo@gnu.org> wrote:
[...]
>> > How a chosen-prefix attack could work here? I understand why the second
>> > preimage attack is an issue. But I miss how the SHA-1 chosen-prefix attack
>> > could be exploited here to compromise the user, because this hash is provided
>> > by this very same user.
>>
>> I think you’re right, it’s rather second-preimage attacks that would be
>> a serious problem. My point is: as time passes, assuming that a SHA1
>> resolves to a single revision on SWH is becoming more and more
>> questionable.
>
> Well, SHA-1 is 2^160 (~10^48.2) and compared to 10^50 which is the
> estimated number of atoms in Earth. Speaking about
> content-addressability, SHA-1 seems fine. However, for security, yeah
> time flies. :-)
True!
>> >> swh: Support downloads of bare Git repositories.
>> >> git: 'update-cached-checkout' can fall back to SWH when cloning.
>> >> git: 'reference-available?' recognizes 'tag-or-commit'.
>>
>> I’ve pushed this after adding the warning as you suggested:
>>
>> dce2cf311b * git: 'reference-available?' recognizes 'tag-or-commit'.
>> 05f44c2d85 * git: 'update-cached-checkout' can fall back to SWH when cloning.
>> 6ec81c31c0 * swh: Support downloads of bare Git repositories.
>
> Cool! I would deserve a --news entry. ;-)
That’s a good idea, I’ve added one.
Thanks,
Ludo’.
prev parent reply other threads:[~2021-09-22 10:04 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 22:17 bug#44187: whishlist: time-machine --channel falls back to SWH zimoun
2021-03-05 14:51 ` Ludovic Courtès
2021-09-10 14:34 ` bug#44187: [PATCH 0/3] Fall back to Software Heritage (SWH) for Git clones Ludovic Courtès
2021-09-10 14:34 ` bug#44187: [PATCH 1/3] swh: Support downloads of bare Git repositories Ludovic Courtès
2021-09-17 17:31 ` bug#44187: Channel clones lack SWH fallback zimoun
2021-09-18 10:05 ` Ludovic Courtès
2021-09-18 10:27 ` zimoun
2021-09-10 14:34 ` bug#44187: [PATCH 2/3] git: 'update-cached-checkout' can fall back to SWH when cloning Ludovic Courtès
2021-09-10 14:34 ` bug#44187: [PATCH 3/3] git: 'reference-available?' recognizes 'tag-or-commit' Ludovic Courtès
2021-09-13 16:07 ` bug#44187: [PATCH 0/3] Fall back to Software Heritage (SWH) for Git clones zimoun
2021-09-14 13:37 ` Ludovic Courtès
2021-09-17 8:02 ` bug#44187: Channel clones lack SWH fallback zimoun
2021-09-18 21:10 ` Ludovic Courtès
2021-09-20 9:27 ` zimoun
2021-09-22 10:03 ` Ludovic Courtès [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87fstxhqq3.fsf@gnu.org \
--to=ludo@gnu.org \
--cc=44187-done@debbugs.gnu.org \
--cc=zimon.toutoune@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/guix.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.