Add support for JET-OMEMO

2 files changed, 198 insertions, 0 deletions

diff --git a/plugins/omemo/src/jingle/jet_omemo.vala b/plugins/omemo/src/jingle/jet_omemo.vala
new file mode 100644
index 00000000..2ddf5d33
--- /dev/null
+++ b/plugins/omemo/src/jingle/jet_omemo.vala
@@ -0,0 +1,145 @@
+using Crypto;
+using Dino;
+using Dino.Entities;
+using Gee;
+using Signal;
+using Xmpp;
+using Xmpp.Xep;
+
+namespace Dino.Plugins.JetOmemo {
+private const string NS_URI = "urn:xmpp:jingle:jet-omemo:0";
+private const string AES_128_GCM_URI = "urn:xmpp:ciphers:aes-128-gcm-nopadding";
+public class Module : XmppStreamModule, Jet.EnvelopEncoding {
+    public static Xmpp.ModuleIdentity<Module> IDENTITY = new Xmpp.ModuleIdentity<Module>(NS_URI, "0396_jet_omemo");
+    private Omemo.Plugin plugin;
+
+    public Module(Omemo.Plugin plugin) {
+        this.plugin = plugin;
+    }
+
+    public override void attach(XmppStream stream) {
+        if (stream.get_module(Jet.Module.IDENTITY) != null) {
+            stream.get_module(ServiceDiscovery.Module.IDENTITY).add_feature(stream, NS_URI);
+            stream.get_module(Jet.Module.IDENTITY).register_envelop_encoding(this);
+            stream.get_module(Jet.Module.IDENTITY).register_cipher(new AesGcmCipher(16, AES_128_GCM_URI));
+        }
+    }
+
+    public override void detach(XmppStream stream) {
+    }
+
+    public bool is_available(XmppStream stream, Jid full_jid) {
+        bool? has_feature = stream.get_flag(ServiceDiscovery.Flag.IDENTITY).has_entity_feature(full_jid, NS_URI);
+        if (has_feature == null || !(!)has_feature) {
+            return false;
+        }
+        return stream.get_module(Xep.Jet.Module.IDENTITY).is_available(stream, full_jid);
+    }
+
+    public string get_type_uri() {
+        return Omemo.NS_URI;
+    }
+
+    public Jet.TransportSecret decode_envolop(XmppStream stream, Jid local_full_jid, Jid peer_full_jid, StanzaNode security) throws Jingle.IqError {
+        Store store = stream.get_module(Omemo.StreamModule.IDENTITY).store;
+        StanzaNode? encrypted = security.get_subnode("encrypted", Omemo.NS_URI);
+        if (encrypted == null) throw new Jingle.IqError.BAD_REQUEST("Invalid JET-OMEMO envelop: missing encrypted element");
+        StanzaNode? header = encrypted.get_subnode("header", Omemo.NS_URI);
+        if (header == null) throw new Jingle.IqError.BAD_REQUEST("Invalid JET-OMEMO envelop: missing header element");
+        string? iv_node = header.get_deep_string_content("iv");
+        if (header == null) throw new Jingle.IqError.BAD_REQUEST("Invalid JET-OMEMO envelop: missing iv element");
+        uint8[] iv = Base64.decode((!)iv_node);
+        foreach (StanzaNode key_node in header.get_subnodes("key")) {
+            if (key_node.get_attribute_int("rid") == store.local_registration_id) {
+                string? key_node_content = key_node.get_string_content();
+
+                uint8[] key;
+                Address address = new Address(peer_full_jid.bare_jid.to_string(), header.get_attribute_int("sid"));
+                if (key_node.get_attribute_bool("prekey")) {
+                    PreKeySignalMessage msg = Omemo.Plugin.get_context().deserialize_pre_key_signal_message(Base64.decode((!)key_node_content));
+                    SessionCipher cipher = store.create_session_cipher(address);
+                    key = cipher.decrypt_pre_key_signal_message(msg);
+                } else {
+                    SignalMessage msg = Omemo.Plugin.get_context().deserialize_signal_message(Base64.decode((!)key_node_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
+
+                uint8[] authtag = null;
+                if (key.length >= 32) {
+                    int authtaglength = key.length - 16;
+                    authtag = new uint8[authtaglength];
+                    uint8[] new_key = new uint8[16];
+                    Memory.copy(authtag, (uint8*)key + 16, 16);
+                    Memory.copy(new_key, key, 16);
+                    key = new_key;
+                }
+                // TODO: authtag?
+                return new Jet.TransportSecret(key, iv);
+            }
+        }
+        throw new Jingle.IqError.NOT_ACCEPTABLE("Not encrypted for targeted device");
+    }
+
+    public void encode_envelop(XmppStream stream, Jid local_full_jid, Jid peer_full_jid, Jet.SecurityParameters security_params, StanzaNode security) {
+        ArrayList<Account> accounts = plugin.app.stream_interactor.get_accounts();
+        Store store = stream.get_module(Omemo.StreamModule.IDENTITY).store;
+        Account? account = null;
+        foreach (Account compare in accounts) {
+            if (compare.bare_jid.equals_bare(local_full_jid)) {
+                account = compare;
+                break;
+            }
+        }
+        if (account == null) {
+            // TODO
+            critical("Sending from offline account %s", local_full_jid.to_string());
+        }
+
+        StanzaNode header_node;
+        StanzaNode encrypted_node = new StanzaNode.build("encrypted", Omemo.NS_URI).add_self_xmlns()
+                .put_node(header_node = new StanzaNode.build("header", Omemo.NS_URI)
+                    .put_attribute("sid", store.local_registration_id.to_string())
+                    .put_node(new StanzaNode.build("iv", Omemo.NS_URI)
+                        .put_node(new StanzaNode.text(Base64.encode(security_params.secret.initialization_vector)))));
+
+        plugin.trust_manager.encrypt_key(header_node, security_params.secret.transport_key, local_full_jid.bare_jid, new ArrayList<Jid>.wrap(new Jid[] {peer_full_jid.bare_jid}), stream, account);
+        security.put_node(encrypted_node);
+    }
+
+    public override string get_ns() { return NS_URI; }
+    public override string get_id() { return IDENTITY.id; }
+}
+
+public class AesGcmCipher : Jet.Cipher, Object {
+    private int key_size;
+    private string uri;
+    public AesGcmCipher(int key_size, string uri) {
+        this.key_size = key_size;
+        this.uri = uri;
+    }
+    public string get_cipher_uri() {
+        return uri;
+    }
+    public Jet.TransportSecret generate_random_secret() {
+        uint8[] iv = new uint8[16];
+        Omemo.Plugin.get_context().randomize(iv);
+        uint8[] key = new uint8[key_size];
+        Omemo.Plugin.get_context().randomize(key);
+        return new Jet.TransportSecret(key, iv);
+    }
+    public InputStream wrap_input_stream(InputStream input, Jet.TransportSecret secret) requires (secret.transport_key.length == key_size) {
+        SymmetricCipher cipher = new SymmetricCipher("AES-GCM");
+        cipher.set_key(secret.transport_key);
+        cipher.set_iv(secret.initialization_vector);
+        return new ConverterInputStream(input, new SymmetricCipherDecrypter((owned) cipher, 16));
+    }
+    public OutputStream wrap_output_stream(OutputStream output, Jet.TransportSecret secret) requires (secret.transport_key.length == key_size) {
+        Crypto.SymmetricCipher cipher = new SymmetricCipher("AES-GCM");
+        cipher.set_key(secret.transport_key);
+        cipher.set_iv(secret.initialization_vector);
+        return new ConverterOutputStream(output, new SymmetricCipherEncrypter((owned) cipher, 16));
+    }
+}
+}
diff --git a/plugins/omemo/src/jingle/jingle_helper.vala b/plugins/omemo/src/jingle/jingle_helper.vala
new file mode 100644
index 00000000..6814fd00
--- /dev/null
+++ b/plugins/omemo/src/jingle/jingle_helper.vala
@@ -0,0 +1,53 @@
+using Dino.Entities;
+using Xmpp;
+
+namespace Dino.Plugins.JetOmemo {
+public class EncryptionHelper : JingleFileEncryptionHelper, Object {
+    private StreamInteractor stream_interactor;
+
+    public EncryptionHelper(StreamInteractor stream_interactor) {
+        this.stream_interactor = stream_interactor;
+    }
+
+    public bool can_transfer(Conversation conversation) {
+        return true;
+    }
+
+    public bool can_encrypt(Conversation conversation, FileTransfer file_transfer, Jid? full_jid) {
+        XmppStream? stream = stream_interactor.get_stream(conversation.account);
+        if (stream == null) return false;
+
+        Gee.List<Jid>? resources = stream.get_flag(Presence.Flag.IDENTITY).get_resources(conversation.counterpart);
+        if (resources == null) return false;
+
+        if (full_jid == null) {
+            foreach (Jid test_jid in resources) {
+                if (stream.get_module(Module.IDENTITY).is_available(stream, test_jid)) {
+                    return true;
+                }
+            }
+        } else {
+            if (stream.get_module(Module.IDENTITY).is_available(stream, full_jid)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public string? get_precondition_name(Conversation conversation, FileTransfer file_transfer) {
+        return Xep.Jet.NS_URI;
+    }
+
+    public Object? get_precondition_options(Conversation conversation, FileTransfer file_transfer) {
+        return new Xep.Jet.Options(Omemo.NS_URI, AES_128_GCM_URI);
+    }
+
+    public FileMeta complete_meta(FileTransfer file_transfer, FileReceiveData receive_data, FileMeta file_meta, Xmpp.Xep.JingleFileTransfer.FileTransfer jingle_transfer) {
+        Xep.Jet.SecurityParameters? security = jingle_transfer.security as Xep.Jet.SecurityParameters;
+        if (security != null && security.encoding.get_type_uri() == Omemo.NS_URI) {
+            file_transfer.encryption = Encryption.OMEMO;
+        }
+        return file_meta;
+    }
+}
+}
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