view mod_s2s_keysize_policy/README.markdown @ 5173:460f78654864

mod_muc_rtbl: also filter messages This was a bit tricky because we don't want to run the JIDs through SHA256 on each message. Took a while to come up with this simple plan of just caching the SHA256 of the JIDs on the occupants. This will leave some dirt in the occupants after unloading the module, but that should be ok; once they cycle the room, the hashes will be gone. This is direly needed, otherwise, there is a tight race between the moderation activities and the actors joining the room.
author Jonas Schäfer <jonas@wielicki.name>
date Tue, 21 Feb 2023 21:37:27 +0100
parents 101078d9cc27
children
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---
summary: Distrust servers with too small keys
...

Introduction
============

This module sets the security status of s2s connections to invalid if
their key is too small and their certificate was issued after 2014, per
CA/B Forum guidelines.

Details
=======

Certificate Authorities were no longer allowed to issue certificates
with public keys smaller than 2048 bits (for RSA) after December 31
2013. This module was written to enforce this, as there were some CAs
that were slow to comply. As of 2015, it might not be very relevant
anymore, but still useful for anyone who wants to increase their
security levels.

When a server is determined to have a "too small" key, this module sets
its chain and identity status to "invalid", so Prosody will treat it as
a self-signed certificate istead.

"Too small"
-----------

The definition of "too small" is based on the key type and is taken from
[RFC 4492].

  Type     bits
  ------ ------
  RSA      2048
  DSA      2048
  DH       2048
  EC        233

Compatibility
=============

Works with Prosody 0.9 and later. Requires LuaSec with [support for
inspecting public keys](https://github.com/brunoos/luasec/pull/19).