Software / code / prosody
File
plugins/muc/occupant.lib.lua @ 13801:a5d5fefb8b68 13.0
mod_tls: Enable Prosody's certificate checking for incoming s2s connections (fixes #1916) (thanks Damian, Zash)
Various options in Prosody allow control over the behaviour of the certificate
verification process For example, some deployments choose to allow falling
back to traditional "dialback" authentication (XEP-0220), while others verify
via DANE, hard-coded fingerprints, or other custom plugins.
Implementing this flexibility requires us to override OpenSSL's default
certificate verification, to allow Prosody to verify the certificate itself,
apply custom policies and make decisions based on the outcome.
To enable our custom logic, we have to suppress OpenSSL's default behaviour of
aborting the connection with a TLS alert message. With LuaSec, this can be
achieved by using the verifyext "lsec_continue" flag.
We also need to use the lsec_ignore_purpose flag, because XMPP s2s uses server
certificates as "client" certificates (for mutual TLS verification in outgoing
s2s connections).
Commit 99d2100d2918 moved these settings out of the defaults and into mod_s2s,
because we only really need these changes for s2s, and they should be opt-in,
rather than automatically applied to all TLS services we offer.
That commit was incomplete, because it only added the flags for incoming
direct TLS connections. StartTLS connections are handled by mod_tls, which was
not applying the lsec_* flags. It previously worked because they were already
in the defaults.
This resulted in incoming s2s connections with "invalid" certificates being
aborted early by OpenSSL, even if settings such as `s2s_secure_auth = false`
or DANE were present in the config.
Outgoing s2s connections inherit verify "none" from the defaults, which means
OpenSSL will receive the cert but will not terminate the connection when it is
deemed invalid. This means we don't need lsec_continue there, and we also
don't need lsec_ignore_purpose (because the remote peer is a "server").
Wondering why we can't just use verify "none" for incoming s2s? It's because
in that mode, OpenSSL won't request a certificate from the peer for incoming
connections. Setting verify "peer" is how you ask OpenSSL to request a
certificate from the client, but also what triggers its built-in verification.
| author | Matthew Wild <mwild1@gmail.com> |
|---|---|
| date | Tue, 01 Apr 2025 17:26:56 +0100 |
| parent | 12977:74b9e05af71e |
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local pairs = pairs; local setmetatable = setmetatable; local st = require "prosody.util.stanza"; local util = module:require "muc/util"; local function get_filtered_presence(stanza) return util.filter_muc_x(st.clone(stanza)); end local occupant_mt = {}; occupant_mt.__index = occupant_mt; local function new_occupant(bare_real_jid, nick) return setmetatable({ bare_jid = bare_real_jid; nick = nick; -- in-room jid sessions = {}; -- hash from real_jid to presence stanzas. stanzas should not be modified role = nil; jid = nil; -- Primary session }, occupant_mt); end -- Deep copy an occupant local function copy_occupant(occupant) local sessions = {}; for full_jid, presence_stanza in pairs(occupant.sessions) do -- Don't keep unavailable presences, as they'll accumulate; unless they're the primary session if presence_stanza.attr.type ~= "unavailable" or full_jid == occupant.jid then sessions[full_jid] = presence_stanza; end end return setmetatable({ bare_jid = occupant.bare_jid; nick = occupant.nick; sessions = sessions; role = occupant.role; jid = occupant.jid; }, occupant_mt); end -- finds another session to be the primary (there might not be one) function occupant_mt:choose_new_primary() for jid, pr in self:each_session() do if pr.attr.type == nil then return jid; end end return nil; end function occupant_mt:set_session(real_jid, presence_stanza, replace_primary) local pr = get_filtered_presence(presence_stanza); pr.attr.from = self.nick; pr.attr.to = real_jid; self.sessions[real_jid] = pr; if replace_primary then self.jid = real_jid; elseif self.jid == nil or (pr.attr.type == "unavailable" and self.jid == real_jid) then -- Only leave an unavailable presence as primary when there are no other options self.jid = self:choose_new_primary() or real_jid; end end function occupant_mt:remove_session(real_jid) -- Delete original session self.sessions[real_jid] = nil; if self.jid == real_jid then self.jid = self:choose_new_primary(); end end function occupant_mt:each_session() return pairs(self.sessions) end function occupant_mt:get_presence(real_jid) return self.sessions[real_jid or self.jid] end return { new = new_occupant; copy = copy_occupant; mt = occupant_mt; }