Afaict this was never used, but keeping this (in theory) possible
hinders detecting which objects are actually media uploads and
which proper ActivityPub objects.
It was originally added as part of upload support itself in
02d3dc6869 without being used
and `git log -S:activity_type` and `git log -Sactivity_type:`
don't find any other commits using this.
This actually was already intended before to eradict all future
path-traversal-style exploits and to fix issues with some
characters like akkoma#610 in 0b2ec0ccee. However, Dedupe and
AnonymizeFilename got mixed up. The latter only anonymises the name
in Content-Disposition headers GET parameters (with link_name),
_not_ the upload path.
Even without Dedupe, the upload path is prefixed by an UUID,
so it _should_ already be hard to guess for attackers. But now
we actually can be sure no path shenanigangs occur, uploads
reliably work and save some disk space.
While this makes the final path predictable, this prediction is
not exploitable. Insertion of a back-reference to the upload
itself requires pulling off a successfull preimage attack against
SHA-256, which is deemed infeasible for the foreseeable futures.
Dedupe was already included in the default list in config.exs
since 28cfb2c37a, but this will get overridde by whatever the
config generated by the "pleroma.instance gen" task chose.
Upload+delete tests running in parallel using Dedupe might be flaky, but
this was already true before and needs its own commit to fix eventually.
When no image description is filled in, Pleroma allowed fallbacks.
Those were (based on a setting) either the filename, or a fixed description.
Neither are good options for image descriptions imo, so here we remove this.
Note that there's two tests removed who supposedly tested something else.
But examining closer, they didn't seem to test what they claimed to test,
so I removed them rather than try to "fix" them.
During attachment upload Pleroma returns a "description" field.
* This MR allows Pleroma to read the EXIF data during upload and return the description to the FE using this field.
* If a description is already present (e.g. because a previous module added it), it will use that
* Otherwise it will read from the EXIF data. First it will check -ImageDescription, if that's empty, it will check -iptc:Caption-Abstract
* If no description is found, it will simply return nil, which is the default value
* When people set up a new instance, they will be asked if they want to read metadata and this module will be activated if so
There was an Exiftool module, which has now been renamed to Exiftool.StripLocation
