Trying to display non-media as media crashed the renderer,
but when posting a status with a valid, non-media object id
the post was still created, but then crashed e.g. timeline rendering.
It also crashed C2S inbox reads, so this could not be used to leak
private posts.
In Mastodon media can only be used by owners and only be associated with
a single post. We currently allow media to be associated with several
posts and until now did not limit their usage in posts to media owners.
However, media update and GET lookup was already limited to owners.
(In accordance with allowing media reuse, we also still allow GET
lookups of media already used in a post unlike Mastodon)
Allowing reuse isn’t problematic per se, but allowing use by non-owners
can be problematic if media ids of private-scoped posts can be guessed
since creating a new post with this media id will reveal the uploaded
file content and alt text.
Given media ids are currently just part of a sequentieal series shared
with some other objects, guessing media ids is with some persistence
indeed feasible.
E.g. sampline some public media ids from a real-world
instance with 112 total and 61 monthly-active users:
17.465.096 at t0
17.472.673 at t1 = t0 + 4h
17.473.248 at t2 = t1 + 20min
This gives about 30 new ids per minute of which most won't be
local media but remote and local posts, poll answers etc.
Assuming the default ratelimit of 15 post actions per 10s, scraping all
media for the 4h interval takes about 84 minutes and scraping the 20min
range mere 6.3 minutes. (Until the preceding commit, post updates were
not rate limited at all, allowing even faster scraping.)
If an attacker can infer (e.g. via reply to a follower-only post not
accessbile to the attacker) some sensitive information was uploaded
during a specific time interval and has some pointers regarding the
nature of the information, identifying the specific upload out of all
scraped media for this timerange is not impossible.
Thus restrict media usage to owners.
Checking ownership just in ActivitDraft would already be sufficient,
since when a scheduled status actually gets posted it goes through
ActivityDraft again, but would erroneously return a success status
when scheduling an illegal post.
Independently discovered and fixed by mint in Pleroma
1afde067b1
The API parameter is not a timestamp but an offset.
If a sufficient amount of time passes between the tests
expires_at calculation and the internal calculation during processing
of the request the strict equality assertion fails. (Either a direct
assertion or indirect via job lookup).
To avoid this lower comparison granularity.
Implements the preferences endpoint in the Mastodon API, but returns
default values for most of the preferences right now. The only supported
preference we can access is default post visibility, and a relevant test
is added as well.
OTP builds to 1.15
Changelog entry
Ensure policies are fully loaded
Fix :warn
use main branch for linkify
Fix warn in tests
Migrations for phoenix 1.17
Revert "Migrations for phoenix 1.17"
This reverts commit 6a3b2f15b74ea5e33150529385215b7a531f3999.
Oban upgrade
Add default empty whitelist
mix format
limit test to amd64
OTP 26 tests for 1.15
use OTP_VERSION tag
baka
just 1.15
Massive deps update
Update locale, deps
Mix format
shell????
multiline???
?
max cases 1
use assert_recieve
don't put_env in async tests
don't async conn/fs tests
mix format
FIx some uploader issues
Fix tests
See https://akkoma.dev/AkkomaGang/akkoma/pulls/350#issuecomment-6109
When making quotes through Mast-API, they will now have the same context as the quoted post. This also results in them being showed when fetching the thread. I checked Misskey to see how it's there, and they show the quotes there as well, see e.g. <https://mk.toast.cafe/notes/98u1g0tulg>.
An example from Akkoma:
Co-authored-by: ilja <git@ilja.space>
Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/379
Reviewed-by: floatingghost <hannah@coffee-and-dreams.uk>
Co-authored-by: ilja <akkoma.dev@ilja.space>
Co-committed-by: ilja <akkoma.dev@ilja.space>
