Commit graph

6700 commits

Author SHA1 Message Date
Oneric f07eb4cb55 Sanity check fetched user data
In order to properly process incoming notes we need
to be able to map the key id back to an actor.
Also, check collections actually belong to the same server.

Key ids of Hubzilla and Bridgy samples were updated to what
modern versions of those output. If anything still uses the
old format, we would not be able to verify their posts anyway.
2024-03-25 14:05:05 -01:00
Oneric d6d838cbe8 StealEmoji: check remote size before downloading
To save on bandwith and avoid OOMs with large files.
Ofc, this relies on the remote server
 (a) sending a content-length header and
 (b) being honest about the size.

Common fedi servers seem to provide the header and (b) at least raises
the required privilege of an malicious actor to a server infrastructure
admin of an explicitly allowed host.

A more complete defense which still works when faced with
a malicious server requires changes in upstream Finch;
see https://github.com/sneako/finch/issues/224
2024-03-18 22:33:10 -01:00
Oneric a4fa2ec9af StealEmoji: make final paths infeasible to predict
Certain attacks rely on predictable paths for their payloads.
If we weren’t so overly lax in our (id, URL) check, the current
counterfeit activity exploit would be one of those.
It seems plausible for future attacks to hinge on
or being made easier by predictable paths too.

In general, letting remote actors place arbitrary data at
a path within our domain of their choosing (sans prefix)
just doesn’t seem like a good idea.

Using fully random filenames would have worked as well, but this
is less friendly for admins checking emoji dirs.
The generated suffix should still be more than enough;
an attacker needs on average 140 trillion attempts to
correctly guess the final path.
2024-03-18 22:33:10 -01:00
Oneric d1c4d07404 Convert StealEmoji to pack.json
This will decouple filenames from shortcodes and
allow more image formats to work instead of only
those included in the auto-load glob. (Albeit we
still saved other formats to disk, wasting space)

Furthermore, this will allow us to make
final URL paths infeasible to predict.
2024-03-18 22:33:10 -01:00
Oneric 5b126567bb StealEmoji: drop superfluous basename
Since 3 commits ago we restrict shortcodes to a subset of
the POSIX Portable Filename Character Set, therefore
this can never have a directory component.
2024-03-18 22:33:10 -01:00
Oneric a8c6c780b4 StealEmoji: use Content-Type and reject non-images
E.g. *key’s emoji URLs typically don’t have file extensions, but
until now we just slapped ".png" at its end hoping for the best.

Furthermore, this gives us a chance to actually reject non-images,
which before was not feasible exatly due to those extension-less URLs
2024-03-18 22:33:10 -01:00
Oneric 111cdb0d86 Split steal_emoji function for better readability 2024-03-18 22:33:10 -01:00
Norm af041db6dc Limit emoji stealer to alphanum, dash, or underscore characters
As suggested in b387f4a1c1, only steal
emoji with alphanumerc, dash, or underscore characters.

Also consolidate all validation logic into a single function.

===

Taken from akkoma#703 with cosmetic tweaks

This matches our existing validation logic from Pleroma.Emoji,
and apart from excluding the dot also POSIX’s Portable Filename
Character Set making it always safe for use in filenames.

Mastodon is even stricter also disallowing U+002D HYPEN-MINUS
and requiring at least two characters.

Given both we and Mastodon reject shortcodes excluded
by this anyway, this doesn’t seem like a loss.
2024-03-18 22:33:10 -01:00
Oneric fc36b04016 Drop media proxy same-domain default for base_url
Even more than with user uploads, a same-domain proxy setup bears
significant security risks due to serving untrusted content under
the main domain space.

A risky setup like that should never be the default.
2024-03-18 22:33:10 -01:00
Oneric e88d0a2853 Fix Content-Type of our schema
Strict servers fail to process anything from us otherwise.

Fixes: akkoma#716
2024-03-18 22:33:10 -01:00
Oneric ba558c0c24 Limit instance emoji to image types
Else malicious emoji packs or our EmojiStealer MRF can
put payloads into the same domain as the instance itself.
Sanitising the content type should prevent proper clients
from acting on any potential payload.

Note, this does not affect the default emoji shipped with Akkoma
as they are handled by another plug. However, those are fully trusted
and thus not in needed of sanitisation.
2024-03-18 22:33:10 -01:00
Oneric bdefbb8fd9 plug/upload_media: query config only once on init 2024-03-18 22:33:10 -01:00
Oneric f7c9793542 Sanitise Content-Type of uploads
The lack thereof enables spoofing ActivityPub objects.

A malicious user could upload fake activities as attachments
and (if having access to remote search) trick local and remote
fedi instances into fetching and processing it as a valid object.

If uploads are hosted on the same domain as the instance itself,
it is possible for anyone with upload access to impersonate(!)
other users of the same instance.
If uploads are exclusively hosted on a different domain, even the most
basic check of domain of the object id and fetch url matching should
prevent impersonation. However, it may still be possible to trick
servers into accepting bogus users on the upload (sub)domain and bogus
notes attributed to such users.
Instances which later migrated to a different domain and have a
permissive redirect rule in place can still be vulnerable.
If — like Akkoma — the fetching server is overly permissive with
redirects, impersonation still works.

This was possible because Plug.Static also uses our custom
MIME type mappings used for actually authentic AP objects.

Provided external storage providers don’t somehow return ActivityStream
Content-Types on their own, instances using those are also safe against
their users being spoofed via uploads.

Akkoma instances using the OnlyMedia upload filter
cannot be exploited as a vector in this way — IF the
fetching server validates the Content-Type of
fetched objects (Akkoma itself does this already).

However, restricting uploads to only multimedia files may be a bit too
heavy-handed. Instead this commit will restrict the returned
Content-Type headers for user uploaded files to a safe subset, falling
back to generic 'application/octet-stream' for anything else.
This will also protect against non-AP payloads as e.g. used in
past frontend code injection attacks.

It’s a slight regression in user comfort, if say PDFs are uploaded,
but this trade-off seems fairly acceptable.

(Note, just excluding our own custom types would offer no protection
 against non-AP payloads and bear a (perhaps small) risk of a silent
 regression should MIME ever decide to add a canonical extension for
 ActivityPub objects)

Now, one might expect there to be other defence mechanisms
besides Content-Type preventing counterfeits from being accepted,
like e.g. validation of the queried URL and AP ID matching.
Inserting a self-reference into our uploads is hard, but unfortunately
*oma does not verify the id in such a way and happily accepts _anything_
from the same domain (without even considering redirects).
E.g. Sharkey (and possibly other *keys) seem to attempt to guard
against this by immediately refetching the object from its ID, but
this is easily circumvented by just uploading two payloads with the
ID of one linking to the other.

Unfortunately *oma is thus _both_ a vector for spoofing and
vulnerable to those spoof payloads, resulting in an easy way
to impersonate our users.

Similar flaws exists for emoji and media proxy.

Subsequent commits will fix this by rigorously sanitising
content types in more areas, hardening our checks, improving
the default config and discouraging insecure config options.
2024-03-18 22:33:10 -01:00
Oneric 7ef93c0b6d Add set_content_type to Plug.StaticNoCT 2024-03-04 17:50:20 +01:00
Oneric dbb6091d01 Import copy of Plug.Static from Plug 1.15.3
The following commit will apply the needed patch
2024-03-04 17:50:20 +01:00
floatingghost 7d61fb0906 Merge pull request 'Fix static-fe Twitter metadata / URL previews' (#700) from Oneric/akkoma:staticfe-metadata into develop
Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/700
2024-02-24 13:42:55 +00:00
FloatingGhost 3111181d3c mix format 2024-02-20 15:09:04 +00:00
Erin Shepherd b387f4a1c1 Don't steal emoji who's shortcodes have dots or colons in their name
Mastodon at the very least seems to prevent the creation of emoji with
dots in their name (and refuses to accept them in federation). It feels
like being cautious in what we accept is reasonable here.

Colons are the emoji separator and so obviously should be blocked.

Perhaps instead of filtering out things like this we should just
do a regex match on `[a-zA-Z0-9_-]`? But that's plausibly a decision
for another day

    Perhaps we should also have a centralised "is this a valid emoji shortcode?"
    function
2024-02-20 11:33:55 +01:00
Haelwenn (lanodan) Monnier 7d94476dd6 StealEmojiPolicy: Sanitize shortcodes
Closes: https://git.pleroma.social/pleroma/pleroma/-/issues/3245
2024-02-20 11:19:00 +01:00
Oneric 37e2a35b86 Fix Twitter metadata
This partly reverts 1d884fd914
while fixing both the issue it addressed and the issue it caused.

The above commit successfully fixed OpenGraph metadata tags
which until then always showed the user bio instead of post content
by handing the activities AP ID as url to the Metadata builder
_instead_ of passing the internal ID as activity_id.
However, in doing so the commit instead inflicted this very problem
onto Twitter metadata tags which ironically are used by akkoma-fe.

This is because while the OpenGraph builder wants an URL as url,
the Twitter builder needs the internal ID to build the URL to the
embedded player for videos and has no URL property.

Thanks to twpol for tracking down this root cause in #644.

Now, once identified the problem is simple, but this simplicity
invites multiple possible solutions to bikeshed about.

 1. Just pass both properties to the builder and let them pick

 2. Drop the url parameter from the OpenGraph builder and instead
     a) build static-fe URL of the post from the ID (like Twitter)
     b) use the passed-in object’s AP ID as an URL

Approach 2a has the disadvantage of hardcoding the expected URL outside
the router, which will be problematic should it ever change.
Approach 2b is conceptually similar to how the builder works atm.
However, the og:url is supposed to be a _permanent_ ID, by changing it
we might, afaiui, technically violate OpenGraph specs(?). (Though its
real-world consequence may very well be near non-existent.)

This leaves just approach 1, which this commit implements.
Albeit it too is not without nits to pick, as it leaves the metadata
builders with an inconsistent interface.

Additionally, this will resolve the subotpimal Discord previews for
content-less image posts reported in #664.
Discord already prefers OpenGraph metadata, so it’s mostly unaffected.
However, it appears when encountering an explicitly empty OpenGraph
description and a non-empty Twitter description, it replaces just the
empty field with its Twitter counterpart, resulting in the user’s bio
slipping into the preview.
Secondly, regardless of any OpenGraph tags, Discord uses twitter:card to
decide how prominently images should be, but due to the bug the card
type was stuck as "summary", forcing images to always remain small.

Root cause identified by: twpol

Fixes: https://akkoma.dev/AkkomaGang/akkoma/issues/644
Fixes: https://akkoma.dev/AkkomaGang/akkoma/issues/664
2024-02-19 21:09:43 +00:00
floatingghost 755c75d8a4 Merge pull request 'Clean up warnings (+fallback metrics)' (#685) from Oneric/akkoma:metrics into develop
Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/685
2024-02-17 11:41:10 +00:00
floatingghost 289f93f5a2 Merge pull request 'Return last_status_at as date, not datetime' (#681) from katafrakt/akkoma:fix-last-status-at into develop
Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/681
2024-02-17 11:37:19 +00:00
Oneric e99e2407f3 Add background_removal to SimplePolicy MRF 2024-02-16 16:36:45 +01:00
Oneric 7622aa27ca Federate user profile background
Currently our own frontend doesn’t show backgrounds of other users, this
property is already publicly readable via REST API and likely was always
intended to be shown and federated.

Recently Sharkey added support for profile backgrounds and
immediately made them federate and be displayed to others.
We use the same AP field as Sharkey here which should make
it interoperable both ways out-of-the-box.

Ref.: 4e64397635
2024-02-16 16:35:51 +01:00
FloatingGhost 0ed815b8a1 Merge branch 'followback' into develop 2024-02-16 13:27:40 +00:00
floatingghost c5dcd07e08 Merge pull request 'Fix OpenAPI spec for preferred_frontend endpoint' (#680) from katafrakt/akkoma:fix-openapi-spec-for-preferred-frontend into develop
Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/680
2024-02-16 12:21:00 +00:00
Oneric cda597a05c doc: fix Akkoma identification name
Akkoma stopped pretending to be Pleroma here when the mix project name
was changed in c07fcdbf2b.
2024-02-15 16:25:59 +01:00
Oneric 376f6b15ca Add ability to auto-approve followbacks
Resolves: https://akkoma.dev/AkkomaGang/akkoma/issues/148
2024-02-13 15:42:37 +01:00
Oneric 13e62b4e51 Fix schema and docs for status_ttl_days and instance
Fixes misspelling and omission of and example in commit
0cfd5b4e89 which added the
status_ttl_property. This was the only place this commit
referred to the property as note_ttl_days.

Partially fixes the omitted schema update of the instance metadata addition
from commit b7e8ce2350. A proper full schema
for nodeinfo is still missing.
2024-02-13 15:39:52 +01:00
Oneric 29f564f700 Use fallbacks of summary metrics for prometheus 2024-02-12 02:00:09 +01:00
Oneric 16197ff57a Display memory as MB in live dashboard
With kilobyte the resulting numbers got too large and were cut off
in the charts, making them useless. However, even an idle Akkoma
server’s memory usage is in the lower hundreths of megabytes, so
we don’t need this much precision to begin with for the dashboard.

Other metric users might prefer base units and can handle scaling in a
smarter way, so keep this configurable.
2024-02-12 02:00:09 +01:00
Oneric a6df71eebb Don't add summary metrics to prometheus
The exporter doesn’t support them thus we don't lose anything by this,
but it avoids a bunch of warnings each time the server starts up.
2024-02-12 01:59:18 +01:00
Paweł Świątkowski df21b61829
Return last_status_at as date, not datetime 2024-02-05 21:42:15 +01:00
floatingghost e97d08ee98 Merge pull request 'MRF transparency: don’t forget to obfuscate short domains' (#676) from Oneric/akkoma:mrf-obfuscation into develop
Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/676
2024-02-05 08:43:43 +00:00
Paweł Świątkowski d7d159c49f
Fix OpenAPI spec for preferred_frontend endpoint
The spec was copied from another endpoint, including the operation id,
leading to scrubbing the valid parameters from the request and simply
not working.
2024-02-03 14:27:45 +01:00
Oneric e47c50666d Fix obfuscation of short domains
Fixes https://akkoma.dev/AkkomaGang/akkoma/issues/645
2024-02-02 14:50:13 +00:00
Aria 77000b8ffd update tests for oauth consumer 2023-12-17 21:48:19 +00:00
Aria eb0dbf6b79 fix oauth consumer mode
the previous code passed a state parameter to ueberauth with info
about where to go after the user logged in, etc.
since ueberauth 0.7, this parameter is ignored and oauth state is used
for actual CSRF reasons.

we now set a cookie with the state we need to keep track of, and read
it once the callback happens.
2023-12-17 19:27:36 +00:00
Yonle 8a0e797cff ap userview: add outbox field.
Signed-off-by: Yonle <yonle@lecturify.net>
2023-12-15 16:31:51 +00:00
FloatingGhost 98f0820ca4 MIX FORMAT 2023-08-15 23:26:22 +01:00
FloatingGhost 9bc0345e57 AND THAT ONE TOO AND ALL 2023-08-15 23:26:08 +01:00
FloatingGhost f3cc60b202 INBOX NEEDS TO BE A FULL URL YOU IDIOT AM BAKA I SHOULD JUST COMMIT SUDOKU RIGHT NOW 2023-08-15 23:23:59 +01:00
FloatingGhost 063e3c0d34 Disallow nil hosts in should_federate 2023-08-15 23:12:04 +01:00
FloatingGhost 6cb40bee26 Migrate to phoenix 1.7 (#626)
Closes #612

Co-authored-by: tusooa <tusooa@kazv.moe>
Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/626
Co-authored-by: FloatingGhost <hannah@coffee-and-dreams.uk>
Co-committed-by: FloatingGhost <hannah@coffee-and-dreams.uk>
2023-08-15 10:22:18 +00:00
FloatingGhost 1bd3012c2d Fix compiler warnings 2023-08-12 15:03:43 +01:00
Joshua Goins c22ecac567 mastodon_api: Add /api/v1/preferences endpoint
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.
2023-08-12 09:28:24 -04:00
FloatingGhost 7825798e32 Add XML matcher 2023-08-07 11:12:14 +01:00
FloatingGhost 9723264fe5 Add URI matchers 2023-08-06 15:51:21 +01:00
FloatingGhost 368b22fd2f Ensure we can't crash out on unusual logger backend settings 2023-08-06 15:12:57 +01:00
mae d868348fac Completely disable xml entity resolution 2023-08-05 12:32:05 +00:00