Added a tracking/epic task on phab: https://phabricator.wikimedia.org/T158986
Attach any specific things to that as subtasks, y'all.
-- brion
On Fri, Feb 24, 2017 at 10:51 AM, Florian Schmidt < florian.schmidt.welzow@t-online.de> wrote:
but this doesn't need to be a "drop everything" hurry task.
Totally agree! :)
Thanks for the information with the page on mediawiki.org. I'll take a look and probably edit it, if I see something :P
Best, Florian
-----Ursprüngliche Nachricht----- Von: Wikitech-l [mailto:wikitech-l-bounces@lists.wikimedia.org] Im Auftrag von Brion Vibber Gesendet: Freitag, 24. Februar 2017 19:48 An: Wikimedia developers wikitech-l@lists.wikimedia.org Betreff: Re: [Wikitech-l] SHA-1 hash officially broken
On Fri, Feb 24, 2017 at 10:34 AM, Florian Schmidt < florian.schmidt.welzow@t-online.de> wrote:
I searched in phabricator, if we've a task already, but couldn't find
any.
However, as the phabricator search and me aren't really good friends, it's possible, that the search wasn't as honest to me, as I would wish and I missed something, so I ask on this list :) Do we've a task already to track the work on this topic? A short github search[1] showed some usages of sha1 (at least the string), so I suspect, that there're some places where we use it, right?
[1] https://github.com/wikimedia/mediawiki/search?utf8=%E2%9C%93&q=SHA1
Usages are listed at https://www.mediawiki.org/wiki/Manual:Hashing -- I've added a "purpose" column on the DB fields list. There might be a couple we missed, so feel free to edit!
It looks like img_sha1 and fa_storage_key are the biggest practical dangers of collision, in that pairs of images could be created such that, say, one is a cute kitten and the other is a shock image, such that deletion and undeletion might surface the wrong file from what the undeleting admin expected.
However since the attack requires creating a common prefix and suffix for the matching pair of files, there's little or no danger of an attack that replaces legitimate files already uploaded by someone else.
I would probably recommend migrating rev_sha1 and img_sha1's usages in collision detection over to a rev_sha256 and img_sha256 columns, and reworking filearchve to use a sha-256 hash for content addressing of new files, but this doesn't need to be a "drop everything" hurry task.
-- brion _______________________________________________ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
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