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-rw-r--r--plugins/mod_s2s_auth_dane_in.lua114
1 files changed, 114 insertions, 0 deletions
diff --git a/plugins/mod_s2s_auth_dane_in.lua b/plugins/mod_s2s_auth_dane_in.lua
new file mode 100644
index 00000000..e2d6743a
--- /dev/null
+++ b/plugins/mod_s2s_auth_dane_in.lua
@@ -0,0 +1,114 @@
+module:set_global();
+
+local dns = require "prosody.net.adns";
+local async = require "prosody.util.async";
+local encodings = require "prosody.util.encodings";
+local hashes = require "prosody.util.hashes";
+local promise = require "prosody.util.promise";
+local x509 = require "prosody.util.x509";
+
+local idna_to_ascii = encodings.idna.to_ascii;
+local sha256 = hashes.sha256;
+local sha512 = hashes.sha512;
+
+local use_dane = module:get_option_boolean("use_dane", nil);
+if use_dane == nil then
+ module:log("warn", "DANE support incomplete, add use_dane = true in the global section to support outgoing s2s connections");
+elseif use_dane == false then
+ module:log("debug", "DANE support disabled with use_dane = false, disabling.")
+ return
+end
+
+local function ensure_secure(r)
+ assert(r.secure, "insecure");
+ return r;
+end
+
+local lazy_tlsa_mt = {
+ __index = function(t, i)
+ if i == 1 then
+ local h = sha256(t[0]);
+ t[1] = h;
+ return h;
+ elseif i == 2 then
+ local h = sha512(t[0]);
+ t[1] = h;
+ return h;
+ end
+ end;
+}
+local function lazy_hash(t)
+ return setmetatable(t, lazy_tlsa_mt);
+end
+
+module:hook("s2s-check-certificate", function(event)
+ local session, host, cert = event.session, event.host, event.cert;
+ local log = session.log or module._log;
+
+ if not host or not cert or session.direction ~= "incoming" then
+ return
+ end
+
+ local by_select_match = {
+ [0] = lazy_hash {
+ -- cert
+ [0] = x509.pem2der(cert:pem());
+
+ };
+ }
+ if cert.pubkey then
+ by_select_match[1] = lazy_hash {
+ -- spki
+ [0] = x509.pem2der(cert:pubkey());
+ };
+ end
+
+ local resolver = dns.resolver();
+
+ local dns_domain = idna_to_ascii(host);
+
+ local function fetch_tlsa(res)
+ local tlsas = {};
+ for _, rr in ipairs(res) do
+ table.insert(tlsas, resolver:lookup_promise(("_%d._tcp.%s"):format(rr.srv.port, rr.srv.target), "TLSA"):next(ensure_secure));
+ end
+ return promise.all(tlsas);
+ end
+
+ local ret = async.wait_for(promise.all({
+ resolver:lookup_promise("_xmpps-server._tcp." .. dns_domain, "SRV"):next(ensure_secure):next(fetch_tlsa);
+ resolver:lookup_promise("_xmpp-server._tcp." .. dns_domain, "SRV"):next(ensure_secure):next(fetch_tlsa);
+ }));
+
+ if not ret then
+ return
+ end
+
+ local found_supported = false;
+ for _, by_proto in ipairs(ret) do
+ for _, by_srv in ipairs(by_proto) do
+ for _, by_target in ipairs(by_srv) do
+ for _, rr in ipairs(by_target) do
+ if rr.tlsa.use == 3 and by_select_match[rr.tlsa.select] and rr.tlsa.match <= 2 then
+ found_supported = true;
+ if rr.tlsa.data == by_select_match[rr.tlsa.select][rr.tlsa.match] then
+ module:log("debug", "%s matches", rr)
+ session.cert_chain_status = "valid";
+ session.cert_identity_status = "valid";
+ return true;
+ end
+ else
+ log("debug", "Unsupported DANE TLSA record: %s", rr);
+ end
+ end
+ end
+ end
+ end
+
+ if found_supported then
+ session.cert_chain_status = "invalid";
+ session.cert_identity_status = nil;
+ return true;
+ end
+
+end, 800);