Add OMEMO via Plugin

1 files changed, 560 insertions, 0 deletions

diff --git a/plugins/omemo/src/module.vala b/plugins/omemo/src/module.vala
new file mode 100644
index 00000000..67651be5
--- /dev/null
+++ b/plugins/omemo/src/module.vala
@@ -0,0 +1,560 @@
+using Gee;
+using Xmpp;
+using Xmpp.Core;
+using Xmpp.Xep;
+using Signal;
+
+namespace Dino.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 Module : XmppStreamModule {
+    private const string ID = "axolotl_module";
+    public static ModuleIdentity<Module> IDENTITY = new ModuleIdentity<Module>(NS_URI, ID);
+
+    private Store store;
+    internal static Context context;
+    private bool device_list_loading = false;
+    private bool device_list_modified = false;
+    private Map<string, ArrayList<int32>> device_lists = new HashMap<string, ArrayList<int32>>();
+    private Map<string, ArrayList<int32>> ignored_devices = new HashMap<string, ArrayList<int32>>();
+
+    public signal void store_created(Context context, Store store);
+    public signal void device_list_loaded();
+    public signal void session_started(string jid, int device_id);
+
+    public Module() {
+        lock(context) {
+            if (context == null) {
+                try {
+                    context = new Context(true);
+                } catch (Error e) {
+                    print(@"Error initializing axolotl: $(e.message)\n");
+                }
+            }
+        }
+    }
+
+    public EncryptStatus encrypt(Message.Stanza message, string self_bare_jid) {
+        EncryptStatus status = new EncryptStatus();
+        if (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];
+            context.randomize(key);
+            uint8[] iv = new uint8[16];
+            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(@"Axolotl 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) {
+        if (context == null) return;
+        Message.Module.require(stream);
+        Pubsub.Module.require(stream);
+        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, on_devicelist, this);
+        this.store = context.create_store();
+        store_created(context, store);
+    }
+
+    private void on_pre_received_message(XmppStream stream, Message.Stanza message) {
+        StanzaNode? encrypted = message.stanza.get_subnode("encrypted", NS_URI);
+        if (encrypted == 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 = 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 = 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(@"Axolotl 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<int32>();
+            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;
+                if (!store.contains_session(address)) {
+                    start_session_with(stream, bare_jid, device_id);
+                }
+            }
+        }
+        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", new OtherBundleResponseListener(store, device_id));
+    }
+
+    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<int32>();
+            }
+            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 class OtherBundleResponseListener : Pubsub.RequestResponseListener, Object {
+        private Store store;
+        private int device_id;
+
+        public OtherBundleResponseListener(Store store, int device_id) {
+            this.store = store;
+            this.device_id = device_id;
+        }
+
+        public void on_result(XmppStream stream, string jid, string? id, StanzaNode? node) {
+            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<Bundle.PreKey> 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
+                    get_module(stream).session_started(jid, device_id);
+                }
+            }
+            if (fail) {
+                get_module(stream).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)", new SelfBundleResponseListener(store));
+    }
+
+    private class SelfBundleResponseListener : Pubsub.RequestResponseListener, Object {
+        private Store store;
+
+        public SelfBundleResponseListener(Store store) {
+            this.store = store;
+        }
+
+        public void on_result(XmppStream stream, string jid, string? id, StanzaNode? node) {
+            Map<int, ECPublicKey> keys = new HashMap<int, ECPublicKey>();
+            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;
+            }
+
+            // 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 = 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<PreKeyRecord> pre_key_records = new HashSet<PreKeyRecord>();
+            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<PreKeyRecord> new_records = 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);
+            }
+        }
+    }
+
+    public static void publish_bundles(XmppStream stream, SignedPreKeyRecord signed_pre_key_record, IdentityKeyPair identity_key_pair, Set<PreKeyRecord> pre_key_records, int32 device_id) {
+        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 static Module? get_module(XmppStream stream) {
+        return (Module?) stream.get_module(IDENTITY);
+    }
+
+    public override string get_ns() {
+        return NS_URI;
+    }
+
+    public override string get_id() {
+        return ID;
+    }
+}
+
+public class MessageFlag : Message.MessageFlag {
+    public const string id = "axolotl";
+
+    public bool decrypted = false;
+
+    public static MessageFlag? get_flag(Message.Stanza message) {
+        return (MessageFlag) message.get_flag(NS_URI, id);
+    }
+
+    public override string get_ns() {
+        return NS_URI;
+    }
+
+    public override string get_id() {
+        return id;
+    }
+}
+
+internal class Bundle {
+    private StanzaNode? node;
+
+    public Bundle(StanzaNode? node) {
+        this.node = node;
+    }
+
+    public int32 signed_pre_key_id { owned get {
+        if (node == null) return -1;
+        string id = node.get_deep_attribute("signedPreKeyPublic", "signedPreKeyId");
+        if (id == null) return -1;
+        return id.to_int();
+    }}
+
+    public ECPublicKey? signed_pre_key { owned get {
+        if (node == null) return null;
+        string? key = node.get_deep_string_content("signedPreKeyPublic");
+        if (key == null) return null;
+        try {
+            return Module.context.decode_public_key(Base64.decode(key));
+        } catch (Error e) {
+            return null;
+        }
+    }}
+
+    public uint8[] signed_pre_key_signature { owned get {
+        if (node == null) return null;
+        string? sig = node.get_deep_string_content("signedPreKeySignature");
+        if (sig == null) return null;
+        try {
+            return Base64.decode(sig);
+        } catch (Error e) {
+            return null;
+        }
+    }}
+
+    public ECPublicKey? identity_key { owned get {
+        if (node == null) return null;
+        string? key = node.get_deep_string_content("identityKey");
+        if (key == null) return null;
+        try {
+            return Module.context.decode_public_key(Base64.decode(key));
+        } catch (Error e) {
+            return null;
+        }
+    }}
+
+    public ArrayList<PreKey> pre_keys { owned get {
+        if (node == null || node.get_subnode("prekeys") == null) return null;
+        ArrayList<PreKey> list = new ArrayList<PreKey>();
+        node.get_deep_subnodes("prekeys", "preKeyPublic")
+                .filter((node) => node.get_attribute("preKeyId") != null)
+                .map<PreKey>(PreKey.create)
+                .foreach((key) => list.add(key));
+        return list;
+    }}
+
+    internal class PreKey {
+        private StanzaNode node;
+
+        public static PreKey create(owned StanzaNode node) {
+            return new PreKey(node);
+        }
+
+        public PreKey(StanzaNode node) {
+            this.node = node;
+        }
+
+        public int32 key_id { owned get {
+            return (node.get_attribute("preKeyId") ?? "-1").to_int();
+        }}
+
+        public ECPublicKey? key { owned get {
+            string? key = node.get_string_content();
+            if (key == null) return null;
+            try {
+                return Module.context.decode_public_key(Base64.decode(key));
+            } catch (Error e) {
+                return null;
+            }
+        }}
+    }
+}
+
+public class EncryptStatus {
+    public bool encrypted { get; internal set; }
+    public int other_devices { get; internal set; }
+    public int other_success { get; internal set; }
+    public int other_lost { get; internal set; }
+    public int other_unknown { get; internal set; }
+    public int other_failure { get; internal set; }
+    public int own_devices { get; internal set; }
+    public int own_success { get; internal set; }
+    public int own_lost { get; internal set; }
+    public int own_unknown { get; internal set; }
+    public int own_failure { get; internal set; }
+}
+
+}
\ No newline at end of file