Move DLTS-SRTP into libdino

1 files changed, 202 insertions, 0 deletions

diff --git a/libdino/src/crypto/openssl/dtls_srtp.vala b/libdino/src/crypto/openssl/dtls_srtp.vala
new file mode 100644
index 00000000..192f0da2
--- /dev/null
+++ b/libdino/src/crypto/openssl/dtls_srtp.vala
@@ -0,0 +1,202 @@
+using OpenSSL;
+
+namespace Dino.Crypto.DtlsSrtp {
+
+public class CredentialsCapsuleOpenSSL : CredentialsCapsule {
+    internal X509.Certificate own_cert;
+    internal EVP.Key private_key;
+}
+
+public CredentialsCapsule generate_credentials () throws GLib.Error {
+    EVP.Key key = new EVP.Key.generate_ecdsa ("prime256v1");
+
+    var start_time = new DateTime.now_local().add_days(-1);
+    var end_time = start_time.add_days (2);
+
+    X509.Certificate cert = new X509.Certificate ();
+    cert.set_public_key (key);
+    cert.set_version (1);
+    cert.not_before.set ((time_t) start_time.to_unix ());
+    cert.not_after.set ((time_t) end_time.to_unix ());
+    cert.serial_number.set (1);
+
+    cert.sign (key, EVP.sha256 ());
+
+    CredentialsCapsuleOpenSSL credentials = new CredentialsCapsuleOpenSSL ();
+    credentials.own_fingerprint = cert.digest (EVP.sha256 ());
+    credentials.own_cert = (owned) cert;
+    credentials.private_key = (owned) key;
+    return credentials;
+}
+
+public class Handler : AbstractHandler {
+
+    public Handler.with_cert (CredentialsCapsule creds) {
+        base.with_cert (creds);
+    }
+
+    protected override Xmpp.Xep.Jingle.ContentEncryption? setup_dtls_connection_thread () {
+        debug("Setting up DTLS connection using OpenSSL. We're %s", mode.to_string());
+        SSL.Context context = new SSL.Context (mode == Mode.SERVER ? SSL.Method.DTLS_SERVER : SSL.Method.DTLS_CLIENT);
+        context.set_tlsext_use_srtp ("SRTP_AES128_CM_SHA1_80");
+        context.use_certificate (((CredentialsCapsuleOpenSSL) credentials).own_cert);
+        context.use_private_key (((CredentialsCapsuleOpenSSL) credentials).private_key);
+        SSL session = new SSL (context);
+        BIO<Handler> bio = new BIO<Handler>(get_handler_based_bio_method());
+        bio.data = this;
+        session.rbio = bio;
+        session.wbio = bio;
+
+        DateTime maximum_time = new DateTime.now_utc().add_seconds(20);
+        int err = 0;
+        if (mode == Mode.SERVER) {
+            session.set_accept_state ();
+        } else {
+            session.set_connect_state ();
+        }
+        do {
+            try {
+                SSL.Error ret = session.do_handshake();
+                switch (ret) {
+                    case SSL.Error.NONE:
+                        err = 1;
+                        break;
+                    case SSL.Error.WANT_READ:
+                        debug ("DTLS wants to read, but nothing in queue, wait for buffer");
+                        buffer_mutex.lock();
+                        if (buffer_queue.size == 0) {
+                            buffer_cond.wait_until(buffer_mutex, get_monotonic_time() + maximum_time.difference(new DateTime.now_utc()));
+                        }
+                        buffer_mutex.unlock();
+                        err = -1;
+                        break;
+                    default:
+                        warning ("DTLS Error: %s", @"$ret");
+                        err = 4;
+                        break;
+                }
+            } catch (Error e) {
+                warning ("DTLS Error: %s", e.message);
+                err = e.code;
+            }
+
+            DateTime current_time = new DateTime.now_utc();
+            if (maximum_time.compare(current_time) < 0) {
+                debug ("DTLS handshake timeouted");
+                err = 2;
+                break;
+            }
+            if (stop) {
+                debug ("DTLS handshake stopped");
+                err = 3;
+                break;
+            }
+        } while (err < 0);
+
+        buffer_mutex.lock();
+        if (stop) {
+            stop = false;
+            running = false;
+            bool restart = restart;
+            buffer_mutex.unlock();
+            if (restart) {
+                debug ("Restarting DTLS handshake");
+                return setup_dtls_connection_thread();
+            }
+            return null;
+        }
+        buffer_mutex.unlock();
+        if (err != 1) {
+            debug ("DTLS handshake failed");
+            return null;
+        }
+
+        // TODO: Check peer certificate
+
+        uint8[] km = new uint8[60];
+        session.export_keying_material (km, "EXTRACTOR-dtls_srtp");
+        uint8[] client_key = km[0:16];
+        uint8[] server_key = km[16:32];
+        uint8[] client_salt = km[32:46];
+        uint8[] server_salt = km[46:60];
+
+        debug ("Finished DTLS connection. We're %s", mode.to_string());
+        if (mode == Mode.SERVER) {
+            srtp_session.set_encryption_key (Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, server_key, server_salt);
+            srtp_session.set_decryption_key (Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, client_key, client_salt);
+        } else {
+            srtp_session.set_encryption_key (Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, client_key, client_salt);
+            srtp_session.set_decryption_key (Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, server_key, server_salt);
+        }
+        return new Xmpp.Xep.Jingle.ContentEncryption (Xmpp.Xep.JingleIceUdp.DTLS_NS_URI, "DTLS-SRTP", credentials.own_fingerprint, peer_fingerprint);
+    }
+
+    private int read_impl (BIO<Handler> bio, uint8[] out_buf) {
+        Bytes data = get_buffer_if_present ();
+        if (data == null) {
+            if (!stop) {
+                debug ("No pending buffer in queue, but end not reached yet, set_retry_read");
+                bio.set_retry_read ();
+            }
+            return -1;
+        }
+        if (data.length > out_buf.length) {
+            warning ("Buffer in queue does not fit in out_buf");
+            return -1;
+        }
+        debug ("Read %d bytes from queue", data.length);
+
+        uint8[] data_uint8 = Bytes.unref_to_data((owned) data);
+        Memory.copy (out_buf, data_uint8, data_uint8.length);
+        bio.clear_retry_flags ();
+        return data_uint8.length;
+    }
+
+    private int write_impl (BIO<Handler> bio, uint8[] buf) {
+        debug ("Write %d bytes to network", buf.length);
+        send_data (buf);
+        return buf.length;
+    }
+
+    private long ctrl_impl (BIO<Handler> bio, BIO.ControlCommand cmd, long num, void* ptr) {
+        switch (cmd) {
+            case BIO.ControlCommand.FLUSH:
+                // Datagrams are sent out immediately
+                return 1;
+            case BIO.ControlCommand.DGRAM_SET_NEXT_TIMEOUT:
+                // Datagrams are sent out immediately
+                return 1;
+            case BIO.ControlCommand.DGRAM_GET_MTU_OVERHEAD:
+                // Just some safe estimate
+                return 70;
+            case BIO.ControlCommand.DGRAM_QUERY_MTU:
+                // Just some safe estimate
+                return 1200;
+            case BIO.ControlCommand.WPENDING:
+                // Datagrams are sent out immediately
+                return 0;
+            case BIO.ControlCommand.POP:
+            case BIO.ControlCommand.PUSH:
+                // Ignored
+                return 0;
+            default:
+                warning (@"Unimplemented ctrl cmd:$cmd, num:$num");
+                return 0;
+        }
+    }
+
+    private static BIO.Method<Handler> _handler_based_bio_method_instance = null;
+
+    private static unowned BIO.Method<Handler> get_handler_based_bio_method () {
+        if (_handler_based_bio_method_instance != null) return _handler_based_bio_method_instance;
+        _handler_based_bio_method_instance = new BIO.Method<Handler> (BIO.Type.SOURCE_SINK | BIO.Type.DGRAM, "Dino DTLS Handler BIO");
+        _handler_based_bio_method_instance.read = (bio, out_buf) => bio.data.read_impl (bio, out_buf);
+        _handler_based_bio_method_instance.write = (bio, buf) => bio.data.write_impl (bio, buf);
+        _handler_based_bio_method_instance.ctrl = (bio, cmd, num, ptr) => bio.data.ctrl_impl (bio, cmd, num, ptr);
+        return _handler_based_bio_method_instance;
+    }
+}
+
+
+
+}
\ No newline at end of file