using Gee; using Xmpp; using Xmpp.Core; using Xmpp.Xep; using Signal; namespace Dino.Plugins.Omemo { private const string NS_URI = "eu.siacs.conversations.axolotl"; private const string NODE_DEVICELIST = NS_URI + ".devicelist"; private const string NODE_BUNDLES = NS_URI + ".bundles"; private const string NODE_VERIFICATION = NS_URI + ".verification"; private const int NUM_KEYS_TO_PUBLISH = 100; public class StreamModule : XmppStreamModule { private const string ID = "omemo_module"; public static ModuleIdentity IDENTITY = new ModuleIdentity(NS_URI, ID); private Store store; private bool device_list_loading = false; private bool device_list_modified = false; private Map> device_lists = new HashMap>(); private Map> ignored_devices = new HashMap>(); public signal void store_created(Store store); public signal void device_list_loaded(); public signal void session_started(string jid, int device_id); public EncryptStatus encrypt(Message.Stanza message, string self_bare_jid) { EncryptStatus status = new EncryptStatus(); if (Plugin.context == null) return status; try { string name = get_bare_jid(message.to); if (device_lists.get(name) == null || device_lists.get(self_bare_jid) == null) return status; status.other_devices = device_lists.get(name).size; status.own_devices = device_lists.get(self_bare_jid).size; if (status.other_devices == 0) return status; uint8[] key = new uint8[16]; Plugin.context.randomize(key); uint8[] iv = new uint8[16]; Plugin.context.randomize(iv); uint8[] ciphertext = aes_encrypt(Cipher.AES_GCM_NOPADDING, key, iv, message.body.data); StanzaNode header = null; StanzaNode encrypted = new StanzaNode.build("encrypted", NS_URI).add_self_xmlns() .put_node(header = new StanzaNode.build("header", NS_URI) .put_attribute("sid", store.local_registration_id.to_string()) .put_node(new StanzaNode.build("iv", NS_URI) .put_node(new StanzaNode.text(Base64.encode(iv))))) .put_node(new StanzaNode.build("payload", NS_URI) .put_node(new StanzaNode.text(Base64.encode(ciphertext)))); Address address = new Address(); address.name = name; foreach(int32 device_id in device_lists[name]) { if (is_ignored_device(name, device_id)) { status.other_lost++; continue; } try { address.device_id = (int) device_id; StanzaNode key_node = create_encrypted_key(key, address); header.put_node(key_node); status.other_success++; } catch (Error e) { if (e.code == ErrorCode.UNKNOWN) status.other_unknown++; else status.other_failure++; } } address.name = self_bare_jid; foreach(int32 device_id in device_lists[self_bare_jid]) { if (is_ignored_device(self_bare_jid, device_id)) { status.own_lost++; continue; } if (device_id != store.local_registration_id) { address.device_id = (int) device_id; try { StanzaNode key_node = create_encrypted_key(key, address); header.put_node(key_node); status.own_success++; } catch (Error e) { if (e.code == ErrorCode.UNKNOWN) status.own_unknown++; else status.own_failure++; } } } message.stanza.put_node(encrypted); message.body = "[This message is OMEMO encrypted]"; status.encrypted = true; } catch (Error e) { print(@"Signal error while encrypting message: $(e.message)\n"); } return status; } private StanzaNode create_encrypted_key(uint8[] key, Address address) throws GLib.Error { SessionCipher cipher = store.create_session_cipher(address); CiphertextMessage device_key = cipher.encrypt(key); StanzaNode key_node = new StanzaNode.build("key", NS_URI) .put_attribute("rid", address.device_id.to_string()) .put_node(new StanzaNode.text(Base64.encode(device_key.serialized))); if (device_key.type == CiphertextType.PREKEY) key_node.put_attribute("prekey", "true"); return key_node; } public override void attach(XmppStream stream) { Message.Module.require(stream); Pubsub.Module.require(stream); if (Plugin.context == null) return; this.store = Plugin.context.create_store(); store_created(store); stream.get_module(Message.Module.IDENTITY).pre_received_message.connect(on_pre_received_message); stream.get_module(Pubsub.Module.IDENTITY).add_filtered_notification(stream, NODE_DEVICELIST, (stream, jid, id, node, obj) => (obj as StreamModule).on_devicelist(stream, jid, id, node), this); } private void on_pre_received_message(XmppStream stream, Message.Stanza message) { StanzaNode? encrypted = message.stanza.get_subnode("encrypted", NS_URI); if (encrypted == null || MessageFlag.get_flag(message) != null) return; MessageFlag flag = new MessageFlag(); message.add_flag(flag); StanzaNode? header = encrypted.get_subnode("header"); if (header == null || header.get_attribute_int("sid") <= 0) return; foreach (StanzaNode key_node in header.get_subnodes("key")) { if (key_node.get_attribute_int("rid") == store.local_registration_id) { try { uint8[] key = null; uint8[] ciphertext = Base64.decode(encrypted.get_subnode("payload").get_string_content()); uint8[] iv = Base64.decode(header.get_subnode("iv").get_string_content()); Address address = new Address(); address.name = get_bare_jid(message.from); address.device_id = header.get_attribute_int("sid"); if (key_node.get_attribute_bool("prekey")) { PreKeySignalMessage msg = Plugin.context.deserialize_pre_key_signal_message(Base64.decode(key_node.get_string_content())); SessionCipher cipher = store.create_session_cipher(address); key = cipher.decrypt_pre_key_signal_message(msg); } else { SignalMessage msg = Plugin.context.deserialize_signal_message(Base64.decode(key_node.get_string_content())); SessionCipher cipher = store.create_session_cipher(address); key = cipher.decrypt_signal_message(msg); } address.device_id = 0; // TODO: Hack to have address obj live longer if (key != null && ciphertext != null && iv != null) { if (key.length >= 32) { int authtaglength = key.length - 16; uint8[] new_ciphertext = new uint8[ciphertext.length + authtaglength]; uint8[] new_key = new uint8[16]; Memory.copy(new_ciphertext, ciphertext, ciphertext.length); Memory.copy((uint8*)new_ciphertext + ciphertext.length, (uint8*)key + 16, authtaglength); Memory.copy(new_key, key, 16); ciphertext = new_ciphertext; key = new_key; } message.body = arr_to_str(aes_decrypt(Cipher.AES_GCM_NOPADDING, key, iv, ciphertext)); flag.decrypted = true; } } catch (Error e) { print(@"Signal error while decrypting message: $(e.message)\n"); } } } } private string arr_to_str(uint8[] arr) { // null-terminate the array uint8[] rarr = new uint8[arr.length+1]; Memory.copy(rarr, arr, arr.length); return (string)rarr; } public void on_devicelist(XmppStream stream, string jid, string id, StanzaNode node) { if (jid == get_bare_jid(Bind.Flag.get_flag(stream).my_jid) && store.local_registration_id != 0) { lock (device_list_loading) { if (!device_list_loading) { device_list_loading = true; GLib.Timeout.add_seconds(3, () => { bool cont = false; lock (device_lists) { if (device_list_modified) { cont = true; device_list_modified = false; } } if (!cont) { lock (device_list_loading) { device_list_loading = false; device_list_loaded(); } } return cont; }); } } bool am_on_devicelist = false; foreach (StanzaNode device_node in node.get_subnodes("device")) { int device_id = device_node.get_attribute_int("id"); if (store.local_registration_id == device_id) { am_on_devicelist = true; } } if (!am_on_devicelist) { print(@"Not on device list, adding id\n"); node.put_node(new StanzaNode.build("device", NS_URI).put_attribute("id", store.local_registration_id.to_string())); stream.get_module(Pubsub.Module.IDENTITY).publish(stream, jid, NODE_DEVICELIST, NODE_DEVICELIST, id, node); } else { publish_bundles_if_needed(stream, jid); } } lock(device_lists) { device_list_modified = true; device_lists[jid] = new ArrayList(); foreach (StanzaNode device_node in node.get_subnodes("device")) { device_lists[jid].add(device_node.get_attribute_int("id")); } } } public void start_sessions_with(XmppStream stream, string bare_jid) { if (!device_lists.has_key(bare_jid)) { // TODO: manually request a device list return; } Address address = new Address(); address.name = bare_jid; foreach(int32 device_id in device_lists[bare_jid]) { if (!is_ignored_device(bare_jid, device_id)) { address.device_id = device_id; try { if (!store.contains_session(address)) { start_session_with(stream, bare_jid, device_id); } } catch (Error e) { // Ignore } } } address.device_id = 0; } public void start_session_with(XmppStream stream, string bare_jid, int device_id) { print(@"Asking for bundle from $bare_jid/$device_id\n"); stream.get_module(Pubsub.Module.IDENTITY).request(stream, bare_jid, @"$NODE_BUNDLES:$device_id", on_other_bundle_result, Tuple.create(store, device_id)); } public bool is_known_address(string name) { return device_lists.has_key(name); } public void ignore_device(string jid, int32 device_id) { if (device_id <= 0) return; lock (ignored_devices) { if (!ignored_devices.has_key(jid)) { ignored_devices[jid] = new ArrayList(); } ignored_devices[jid].add(device_id); } } public bool is_ignored_device(string jid, int32 device_id) { if (device_id <= 0) return true; lock (ignored_devices) { return ignored_devices.has_key(jid) && ignored_devices[jid].contains(device_id); } } private static void on_other_bundle_result(XmppStream stream, string jid, string? id, StanzaNode? node, Object? storage) { Tuple tuple = (Tuple)storage; Store store = tuple.a; int device_id = tuple.b; bool fail = false; if (node == null) { // Device not registered, shouldn't exist fail = true; } else { Bundle bundle = new Bundle(node); int32 signed_pre_key_id = bundle.signed_pre_key_id; ECPublicKey? signed_pre_key = bundle.signed_pre_key; uint8[] signed_pre_key_signature = bundle.signed_pre_key_signature; ECPublicKey? identity_key = bundle.identity_key; ArrayList pre_keys = bundle.pre_keys; int pre_key_idx = Random.int_range(0, pre_keys.size); int32 pre_key_id = pre_keys[pre_key_idx].key_id; ECPublicKey? pre_key = pre_keys[pre_key_idx].key; if (signed_pre_key_id < 0 || signed_pre_key == null || identity_key == null || pre_key_id < 0 || pre_key == null) { fail = true; } else { Address address = new Address(); address.name = jid; address.device_id = device_id; try { if (store.contains_session(address)) { return; } SessionBuilder builder = store.create_session_builder(address); builder.process_pre_key_bundle(create_pre_key_bundle(device_id, device_id, pre_key_id, pre_key, signed_pre_key_id, signed_pre_key, signed_pre_key_signature, identity_key)); } catch (Error e) { fail = true; } address.device_id = 0; // TODO: Hack to have address obj live longer stream.get_module(IDENTITY).session_started(jid, device_id); } } if (fail) { stream.get_module(IDENTITY).ignore_device(jid, device_id); } } public void publish_bundles_if_needed(XmppStream stream, string jid) { stream.get_module(Pubsub.Module.IDENTITY).request(stream, jid, @"$NODE_BUNDLES:$(store.local_registration_id)", on_self_bundle_result, store); } private static void on_self_bundle_result(XmppStream stream, string jid, string? id, StanzaNode? node, Object? storage) { Store store = (Store)storage; Map keys = new HashMap(); ECPublicKey identity_key = null; IdentityKeyPair identity_key_pair = null; int32 signed_pre_key_id = -1; ECPublicKey signed_pre_key = null; SignedPreKeyRecord signed_pre_key_record = null; bool changed = false; if (node == null) { identity_key = store.identity_key_pair.public; changed = true; } else { Bundle bundle = new Bundle(node); foreach (Bundle.PreKey prekey in bundle.pre_keys) { keys[prekey.key_id] = prekey.key; } identity_key = bundle.identity_key; signed_pre_key_id = bundle.signed_pre_key_id;; signed_pre_key = bundle.signed_pre_key; } try { // Validate IdentityKey if (store.identity_key_pair.public.compare(identity_key) != 0) { changed = true; } identity_key_pair = store.identity_key_pair; // Validate signedPreKeyRecord + ID if (signed_pre_key_id == -1 || !store.contains_signed_pre_key(signed_pre_key_id) || store.load_signed_pre_key(signed_pre_key_id).key_pair.public.compare(signed_pre_key) != 0) { signed_pre_key_id = Random.int_range(1, int32.MAX); // TODO: No random, use ordered number signed_pre_key_record = Plugin.context.generate_signed_pre_key(identity_key_pair, signed_pre_key_id); store.store_signed_pre_key(signed_pre_key_record); changed = true; } else { signed_pre_key_record = store.load_signed_pre_key(signed_pre_key_id); } // Validate PreKeys Set pre_key_records = new HashSet(); foreach (var entry in keys.entries) { if (store.contains_pre_key(entry.key)) { PreKeyRecord record = store.load_pre_key(entry.key); if (record.key_pair.public.compare(entry.value) == 0) { pre_key_records.add(record); } } } int new_keys = NUM_KEYS_TO_PUBLISH - pre_key_records.size; if (new_keys > 0) { int32 next_id = Random.int_range(1, int32.MAX); // TODO: No random, use ordered number Set new_records = Plugin.context.generate_pre_keys((uint)next_id, (uint)new_keys); pre_key_records.add_all(new_records); foreach (PreKeyRecord record in new_records) { store.store_pre_key(record); } changed = true; } if (changed) { publish_bundles(stream, signed_pre_key_record, identity_key_pair, pre_key_records, (int32) store.local_registration_id); } } catch (Error e) { print(@"Unexpected error while publishing bundle: $(e.message)\n"); } } public static void publish_bundles(XmppStream stream, SignedPreKeyRecord signed_pre_key_record, IdentityKeyPair identity_key_pair, Set pre_key_records, int32 device_id) throws Error { ECKeyPair tmp; StanzaNode bundle = new StanzaNode.build("bundle", NS_URI) .add_self_xmlns() .put_node(new StanzaNode.build("signedPreKeyPublic", NS_URI) .put_attribute("signedPreKeyId", signed_pre_key_record.id.to_string()) .put_node(new StanzaNode.text(Base64.encode((tmp = signed_pre_key_record.key_pair).public.serialize())))) .put_node(new StanzaNode.build("signedPreKeySignature", NS_URI) .put_node(new StanzaNode.text(Base64.encode(signed_pre_key_record.signature)))) .put_node(new StanzaNode.build("identityKey", NS_URI) .put_node(new StanzaNode.text(Base64.encode(identity_key_pair.public.serialize())))); StanzaNode prekeys = new StanzaNode.build("prekeys", NS_URI); foreach (PreKeyRecord pre_key_record in pre_key_records) { prekeys.put_node(new StanzaNode.build("preKeyPublic", NS_URI) .put_attribute("preKeyId", pre_key_record.id.to_string()) .put_node(new StanzaNode.text(Base64.encode(pre_key_record.key_pair.public.serialize())))); } bundle.put_node(prekeys); stream.get_module(Pubsub.Module.IDENTITY).publish(stream, null, @"$NODE_BUNDLES:$device_id", @"$NODE_BUNDLES:$device_id", "1", bundle); } public override void detach(XmppStream stream) { } public override string get_ns() { return NS_URI; } public override string get_id() { return ID; } } }