Tweak signature verification (#15069)

* Add more specific error message when request body digest is invalid

This may help other implementors debug their implementation.

* Relax Host parameter requirement to GET requests

The only POST requests processed by Mastodon need objects/actors (including
their host) to be explicitly mentioned in the request's body, so replaying
a legitimate request to another host should not be a security issue.

* Support Digest headers using multiple algorithms or lowercase alogirthm names

0 files changed, 0 insertions, 0 deletions