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
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.
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.
fixed up some grammer / wording. removed a setence and made wording more in line with what I could find in Admin-FE (especially wording of "rejecting" vs. dropping)
This vastly reduces idle CPU usage, which should generally be beneficial
for most small-to-medium sized instances.
Additionally update the documentation to specify how to override the vm.args
file for OTP installs
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.
Erin Shepherd
