view mod_e2e_policy/mod_e2e_policy.lua @ 5256:44f7edd4f845

mod_http_oauth2: Reject non-local hosts in more code paths We're not issuing tokens for users on remote hosts, we can't even authenticate them since they're remote. Thus the host is always the local module.host so no need to pass around the host in most cases or use it for anything but enforcing the same host.
author Kim Alvefur <zash@zash.se>
date Thu, 16 Mar 2023 17:52:10 +0100
parents a76c420eca61
children
line wrap: on
line source

local st = require "util.stanza";
local jid_bare = require "util.jid".bare;
local host = module.host;
local e2e_policy_chat = module:get_option_string("e2e_policy_chat", "optional"); -- possible values: none, optional and required
local e2e_policy_muc = module:get_option_string("e2e_policy_muc", "optional"); -- possible values: none, optional and required
local e2e_policy_whitelist = module:get_option_set("e2e_policy_whitelist", {  }); -- make this module ignore messages sent to and from this JIDs or MUCs

local e2e_policy_message_optional_chat = module:get_option_string("e2e_policy_message_optional_chat", "For security reasons, OMEMO, OTR or PGP encryption is STRONGLY recommended for conversations on this server.");
local e2e_policy_message_required_chat = module:get_option_string("e2e_policy_message_required_chat", "For security reasons, OMEMO, OTR or PGP encryption is required for conversations on this server.");
local e2e_policy_message_optional_muc = module:get_option_string("e2e_policy_message_optional_muc", "For security reasons, OMEMO, OTR or PGP encryption is STRONGLY recommended for MUC on this server.");
local e2e_policy_message_required_muc = module:get_option_string("e2e_policy_message_required_muc", "For security reasons, OMEMO, OTR or PGP encryption is required for MUC on this server.");

function warn_on_plaintext_messages(event)
    -- check if JID is whitelisted
    if e2e_policy_whitelist:contains(jid_bare(event.stanza.attr.from)) or e2e_policy_whitelist:contains(jid_bare(event.stanza.attr.to)) then
        return nil;
    end
    local body = event.stanza:get_child_text("body");
    -- do not warn for status messages
    if not body or event.stanza.attr.type == "error" then
        return nil;
    end
    -- check otr
    if body and body:sub(1,4) == "?OTR" then
        return nil;
    end
    -- check omemo https://xmpp.org/extensions/inbox/omemo.html
    if event.stanza:get_child("encrypted", "eu.siacs.conversations.axolotl") or event.stanza:get_child("encrypted", "urn:xmpp:omemo:0") then
        return nil;
    end
    -- check xep27 pgp https://xmpp.org/extensions/xep-0027.html
    if event.stanza:get_child("x", "jabber:x:encrypted") then
        return nil;
    end
    -- check xep373 pgp (OX) https://xmpp.org/extensions/xep-0373.html
    if event.stanza:get_child("openpgp", "urn:xmpp:openpgp:0") then
        return nil;
    end
    -- no valid encryption found
    if e2e_policy_chat == "optional" and event.stanza.attr.type ~= "groupchat" then
        event.origin.send(st.message({ from = host, to = event.stanza.attr.from, type = "headline" }, e2e_policy_message_optional_chat));
    end
    if e2e_policy_chat == "required" and event.stanza.attr.type ~= "groupchat" then
        return event.origin.send(st.error_reply(event.stanza, "modify", "policy-violation", e2e_policy_message_required_chat));
    end
    if e2e_policy_muc == "optional" and event.stanza.attr.type == "groupchat" then
        event.origin.send(st.message({ from = host, to = event.stanza.attr.from, type = "headline" }, e2e_policy_message_optional_muc));
    end
    if e2e_policy_muc == "required" and event.stanza.attr.type == "groupchat" then
        return event.origin.send(st.error_reply(event.stanza, "modify", "policy-violation", e2e_policy_message_required_muc));
    end
end

module:hook("pre-message/bare", warn_on_plaintext_messages, 300);
module:hook("pre-message/full", warn_on_plaintext_messages, 300);
module:hook("pre-message/host", warn_on_plaintext_messages, 300);