using Signal; using Gee; using Xmpp; namespace Dino.Plugins.Omemo.DtlsSrtpVerificationDraft { public const string NS_URI = "http://gultsch.de/xmpp/drafts/omemo/dlts-srtp-verification"; public class StreamModule : XmppStreamModule { public static Xmpp.ModuleIdentity IDENTITY = new Xmpp.ModuleIdentity(NS_URI, "dtls_srtp_omemo_verification_draft"); private VerificationSendListener send_listener = new VerificationSendListener(); private HashMap device_id_by_jingle_sid = new HashMap(); private HashMap> content_names_by_jingle_sid = new HashMap>(); private void on_preprocess_incoming_iq_set_get(XmppStream stream, Xmpp.Iq.Stanza iq) { if (iq.type_ != Iq.Stanza.TYPE_SET) return; Gee.List content_nodes = iq.stanza.get_deep_subnodes(Xep.Jingle.NS_URI + ":jingle", Xep.Jingle.NS_URI + ":content"); if (content_nodes.size == 0) return; string? jingle_sid = iq.stanza.get_deep_attribute(Xep.Jingle.NS_URI + ":jingle", "sid"); if (jingle_sid == null) return; Xep.Omemo.OmemoDecryptor decryptor = stream.get_module(Xep.Omemo.OmemoDecryptor.IDENTITY); foreach (StanzaNode content_node in content_nodes) { string? content_name = content_node.get_attribute("name"); if (content_name == null) continue; StanzaNode? transport_node = content_node.get_subnode("transport", Xep.JingleIceUdp.NS_URI); if (transport_node == null) continue; StanzaNode? fingerprint_node = transport_node.get_subnode("fingerprint", NS_URI); if (fingerprint_node == null) continue; StanzaNode? encrypted_node = fingerprint_node.get_subnode("encrypted", Omemo.NS_URI); if (encrypted_node == null) continue; Xep.Omemo.ParsedData? parsed_data = decryptor.parse_node(encrypted_node); if (parsed_data == null || parsed_data.ciphertext == null) continue; if (device_id_by_jingle_sid.has_key(jingle_sid) && device_id_by_jingle_sid[jingle_sid] != parsed_data.sid) { warning("Expected DTLS fingerprint to be OMEMO encrypted from %s %d, but it was from %d", iq.from.to_string(), device_id_by_jingle_sid[jingle_sid], parsed_data.sid); } foreach (Bytes encr_key in parsed_data.our_potential_encrypted_keys.keys) { parsed_data.is_prekey = parsed_data.our_potential_encrypted_keys[encr_key]; parsed_data.encrypted_key = encr_key.get_data(); try { uint8[] key = decryptor.decrypt_key(parsed_data, iq.from.bare_jid); string cleartext = decryptor.decrypt(parsed_data.ciphertext, key, parsed_data.iv); StanzaNode new_fingerprint_node = new StanzaNode.build("fingerprint", Xep.JingleIceUdp.DTLS_NS_URI).add_self_xmlns() .put_node(new StanzaNode.text(cleartext)); string? hash_attr = fingerprint_node.get_attribute("hash", NS_URI); string? setup_attr = fingerprint_node.get_attribute("setup", NS_URI); if (hash_attr != null) new_fingerprint_node.put_attribute("hash", hash_attr); if (setup_attr != null) new_fingerprint_node.put_attribute("setup", setup_attr); transport_node.put_node(new_fingerprint_node); device_id_by_jingle_sid[jingle_sid] = parsed_data.sid; if (!content_names_by_jingle_sid.has_key(content_name)) { content_names_by_jingle_sid[content_name] = new ArrayList(); } content_names_by_jingle_sid[content_name].add(content_name); stream.get_flag(Xep.Jingle.Flag.IDENTITY).get_session.begin(jingle_sid, (_, res) => { Xep.Jingle.Session? session = stream.get_flag(Xep.Jingle.Flag.IDENTITY).get_session.end(res); if (session == null || !session.contents_map.has_key(content_name)) return; var encryption = new OmemoContentEncryption() { encryption_ns=NS_URI, encryption_name="OMEMO", our_key=new uint8[0], peer_key=new uint8[0], peer_device_id=device_id_by_jingle_sid[jingle_sid] }; session.contents_map[content_name].encryptions[NS_URI] = encryption; if (iq.stanza.get_deep_attribute(Xep.Jingle.NS_URI + ":jingle", "action") == "session-accept") { session.additional_content_add_incoming.connect(on_content_add_received); } }); break; } catch (Error e) { debug("Decrypting message from %s/%d failed: %s", iq.from.bare_jid.to_string(), parsed_data.sid, e.message); } } } } private void on_preprocess_outgoing_iq_set_get(XmppStream stream, Xmpp.Iq.Stanza iq) { if (iq.type_ != Iq.Stanza.TYPE_SET) return; StanzaNode? jingle_node = iq.stanza.get_subnode("jingle", Xep.Jingle.NS_URI); if (jingle_node == null) return; string? sid = jingle_node.get_attribute("sid", Xep.Jingle.NS_URI); if (sid == null || !device_id_by_jingle_sid.has_key(sid)) return; Gee.List content_nodes = jingle_node.get_subnodes("content", Xep.Jingle.NS_URI); if (content_nodes.size == 0) return; foreach (StanzaNode content_node in content_nodes) { StanzaNode? transport_node = content_node.get_subnode("transport", Xep.JingleIceUdp.NS_URI); if (transport_node == null) continue; StanzaNode? fingerprint_node = transport_node.get_subnode("fingerprint", Xep.JingleIceUdp.DTLS_NS_URI); if (fingerprint_node == null) continue; string fingerprint = fingerprint_node.get_deep_string_content(); Xep.Omemo.OmemoEncryptor encryptor = stream.get_module(Xep.Omemo.OmemoEncryptor.IDENTITY); Xep.Omemo.EncryptionData enc_data = encryptor.encrypt_plaintext(fingerprint); encryptor.encrypt_key(enc_data, iq.to.bare_jid, device_id_by_jingle_sid[sid]); StanzaNode new_fingerprint_node = new StanzaNode.build("fingerprint", NS_URI).add_self_xmlns().put_node(enc_data.get_encrypted_node()); string? hash_attr = fingerprint_node.get_attribute("hash", Xep.JingleIceUdp.DTLS_NS_URI); string? setup_attr = fingerprint_node.get_attribute("setup", Xep.JingleIceUdp.DTLS_NS_URI); if (hash_attr != null) new_fingerprint_node.put_attribute("hash", hash_attr); if (setup_attr != null) new_fingerprint_node.put_attribute("setup", setup_attr); transport_node.put_node(new_fingerprint_node); transport_node.sub_nodes.remove(fingerprint_node); } } private void on_message_received(XmppStream stream, Xmpp.MessageStanza message) { StanzaNode? proceed_node = message.stanza.get_subnode("proceed", Xep.JingleMessageInitiation.NS_URI); if (proceed_node == null) return; string? jingle_sid = proceed_node.get_attribute("id"); if (jingle_sid == null) return; StanzaNode? device_node = proceed_node.get_subnode("device", NS_URI); if (device_node == null) return; int device_id = device_node.get_attribute_int("id", -1); if (device_id == -1) return; device_id_by_jingle_sid[jingle_sid] = device_id; } private void on_session_initiate_received(XmppStream stream, Xep.Jingle.Session session) { if (device_id_by_jingle_sid.has_key(session.sid)) { foreach (Xep.Jingle.Content content in session.contents) { on_content_add_received(stream, content); } } session.additional_content_add_incoming.connect(on_content_add_received); } private void on_content_add_received(XmppStream stream, Xep.Jingle.Content content) { if (!content_names_by_jingle_sid.has_key(content.session.sid) || content_names_by_jingle_sid[content.session.sid].contains(content.content_name)) { var encryption = new OmemoContentEncryption() { encryption_ns=NS_URI, encryption_name="OMEMO", our_key=new uint8[0], peer_key=new uint8[0], peer_device_id=device_id_by_jingle_sid[content.session.sid] }; content.encryptions[encryption.encryption_ns] = encryption; } } public override void attach(XmppStream stream) { stream.get_module(Xmpp.MessageModule.IDENTITY).received_message.connect(on_message_received); stream.get_module(Xmpp.MessageModule.IDENTITY).send_pipeline.connect(send_listener); stream.get_module(Xmpp.Iq.Module.IDENTITY).preprocess_incoming_iq_set_get.connect(on_preprocess_incoming_iq_set_get); stream.get_module(Xmpp.Iq.Module.IDENTITY).preprocess_outgoing_iq_set_get.connect(on_preprocess_outgoing_iq_set_get); stream.get_module(Xep.Jingle.Module.IDENTITY).session_initiate_received.connect(on_session_initiate_received); } public override void detach(XmppStream stream) { stream.get_module(Xmpp.MessageModule.IDENTITY).received_message.disconnect(on_message_received); stream.get_module(Xmpp.MessageModule.IDENTITY).send_pipeline.disconnect(send_listener); stream.get_module(Xmpp.Iq.Module.IDENTITY).preprocess_incoming_iq_set_get.disconnect(on_preprocess_incoming_iq_set_get); stream.get_module(Xmpp.Iq.Module.IDENTITY).preprocess_outgoing_iq_set_get.disconnect(on_preprocess_outgoing_iq_set_get); stream.get_module(Xep.Jingle.Module.IDENTITY).session_initiate_received.disconnect(on_session_initiate_received); } public override string get_ns() { return NS_URI; } public override string get_id() { return IDENTITY.id; } } public class VerificationSendListener : StanzaListener { private const string[] after_actions_const = {}; public override string action_group { get { return "REWRITE_NODES"; } } public override string[] after_actions { get { return after_actions_const; } } public override async bool run(XmppStream stream, MessageStanza message) { StanzaNode? proceed_node = message.stanza.get_subnode("proceed", Xep.JingleMessageInitiation.NS_URI); if (proceed_node == null) return false; StanzaNode device_node = new StanzaNode.build("device", NS_URI).add_self_xmlns() .put_attribute("id", stream.get_module(Omemo.StreamModule.IDENTITY).store.local_registration_id.to_string()); proceed_node.put_node(device_node); return false; } } public class OmemoContentEncryption : Xep.Jingle.ContentEncryption { public int peer_device_id { get; set; } } }