mod_s2s_keysize_policy/README.markdown
author Matthew Wild <mwild1@gmail.com>
Thu, 22 Sep 2022 18:25:44 +0100
changeset 5053 e89aad13a52a
parent 1899 101078d9cc27
permissions -rw-r--r--
mod_sasl2: Further break up success handling, into pre/post stream:features This allows us to enable mod_smacks after sending success, but before sending stream:features. Previously, the features were being calculated before SM was finalized on the session. We can't finalize SM before sending <success> because it may generate stanzas.

---
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).