DTLS-SRTP: Wait for setup finish and handle setup=passive

2 files changed, 147 insertions, 80 deletions

diff --git a/plugins/ice/src/dtls_srtp.vala b/plugins/ice/src/dtls_srtp.vala
index e2470cf6..8a9b5dfa 100644
--- a/plugins/ice/src/dtls_srtp.vala
+++ b/plugins/ice/src/dtls_srtp.vala
@@ -1,9 +1,26 @@
 using GnuTLS;
 
-public class DtlsSrtp {
+namespace Dino.Plugins.Ice.DtlsSrtp {
+
+public static Handler setup() throws GLib.Error {
+    var obj = new Handler();
+    obj.generate_credentials();
+    return obj;
+}
+
+public class Handler {
 
     public signal void send_data(uint8[] data);
 
+    public bool ready { get {
+        return srtp_session.has_encrypt && srtp_session.has_decrypt;
+    }}
+
+    public Mode mode { get; set; default = Mode.CLIENT; }
+    public uint8[] own_fingerprint { get; private set; }
+    public uint8[] peer_fingerprint { get; set; }
+    public string peer_fp_algo { get; set; }
+
     private X509.Certificate[] own_cert;
     private X509.PrivateKey private_key;
     private Cond buffer_cond = new Cond();
@@ -11,27 +28,12 @@ public class DtlsSrtp {
     private Gee.LinkedList<Bytes> buffer_queue = new Gee.LinkedList<Bytes>();
     private uint pull_timeout = uint.MAX;
 
-    private DigestAlgorithm? peer_fp_algo = null;
-    private uint8[] peer_fingerprint = null;
-    private uint8[] own_fingerprint;
+    private bool running = false;
+    private bool stop = false;
+    private bool restart = false;
 
     private Crypto.Srtp.Session srtp_session = new Crypto.Srtp.Session();
 
-    public static DtlsSrtp setup() throws GLib.Error {
-        var obj = new DtlsSrtp();
-        obj.generate_credentials();
-        return obj;
-    }
-
-    internal uint8[] get_own_fingerprint(DigestAlgorithm digest_algo) {
-        return own_fingerprint;
-    }
-
-    public void set_peer_fingerprint(uint8[] fingerprint, DigestAlgorithm digest_algo) {
-        this.peer_fingerprint = fingerprint;
-        this.peer_fp_algo = digest_algo;
-    }
-
     public uint8[] process_incoming_data(uint component_id, uint8[] data) {
         if (srtp_session.has_decrypt) {
             try {
@@ -77,7 +79,7 @@ public class DtlsSrtp {
         buffer_mutex.unlock();
     }
 
-    private void generate_credentials() throws GLib.Error {
+    internal void generate_credentials() throws GLib.Error {
         int err = 0;
 
         private_key = X509.PrivateKey.create();
@@ -102,8 +104,29 @@ public class DtlsSrtp {
         own_cert = new X509.Certificate[] { (owned)cert };
     }
 
-    public async Xmpp.Xep.Jingle.ContentEncryption setup_dtls_connection(bool server) {
-        InitFlags server_or_client = server ? InitFlags.SERVER : InitFlags.CLIENT;
+    public void stop_dtls_connection() {
+        buffer_mutex.lock();
+        stop = true;
+        buffer_cond.signal();
+        buffer_mutex.unlock();
+    }
+
+    public async Xmpp.Xep.Jingle.ContentEncryption? setup_dtls_connection() {
+        buffer_mutex.lock();
+        if (stop) {
+            restart = true;
+            buffer_mutex.unlock();
+            return null;
+        }
+        if (running || ready) {
+            buffer_mutex.unlock();
+            return null;
+        }
+        running = true;
+        restart = false;
+        buffer_mutex.unlock();
+
+        InitFlags server_or_client = mode == Mode.SERVER ? InitFlags.SERVER : InitFlags.CLIENT;
         debug("Setting up DTLS connection. We're %s", server_or_client.to_string());
 
         CertificateCredentials cert_cred = CertificateCredentials.create();
@@ -131,7 +154,7 @@ public class DtlsSrtp {
                 DateTime current_time = new DateTime.now_utc();
                 if (maximum_time.compare(current_time) < 0) {
                     warning("DTLS handshake timeouted");
-                    return -1;
+                    return ErrorCode.APPLICATION_ERROR_MIN + 1;
                 }
             } while (err < 0 && !((ErrorCode)err).is_fatal());
             Idle.add(setup_dtls_connection.callback);
@@ -139,6 +162,17 @@ public class DtlsSrtp {
         });
         yield;
         err = thread.join();
+        buffer_mutex.lock();
+        if (stop) {
+            stop = false;
+            running = false;
+            bool restart = restart;
+            buffer_mutex.unlock();
+            if (restart) return yield setup_dtls_connection();
+            return null;
+        }
+        buffer_mutex.unlock();
+        throw_if_error(err);
 
         uint8[] km = new uint8[150];
         Datum? client_key, client_salt, server_key, server_salt;
@@ -147,7 +181,8 @@ public class DtlsSrtp {
             warning("SRTP client/server key/salt null");
         }
 
-        if (server) {
+        debug("Finished DTLS connection. We're %s", server_or_client.to_string());
+        if (mode == Mode.SERVER) {
             srtp_session.set_encryption_key(Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, server_key.extract(), server_salt.extract());
             srtp_session.set_decryption_key(Crypto.Srtp.AES_CM_128_HMAC_SHA1_80, client_key.extract(), client_salt.extract());
         } else {
@@ -158,24 +193,28 @@ public class DtlsSrtp {
     }
 
     private static ssize_t pull_function(void* transport_ptr, uint8[] buffer) {
-        DtlsSrtp self = transport_ptr as DtlsSrtp;
+        Handler self = transport_ptr as Handler;
 
         self.buffer_mutex.lock();
         while (self.buffer_queue.size == 0) {
             self.buffer_cond.wait(self.buffer_mutex);
+            if (self.stop) {
+                self.buffer_mutex.unlock();
+                return -1;
+            }
         }
-        owned Bytes data = self.buffer_queue.remove_at(0);
+        Bytes data = self.buffer_queue.remove_at(0);
         self.buffer_mutex.unlock();
 
-        uint8[] data_uint8 = Bytes.unref_to_data(data);
+        uint8[] data_uint8 = Bytes.unref_to_data((owned) data);
         Memory.copy(buffer, data_uint8, data_uint8.length);
 
         // The callback should return 0 on connection termination, a positive number indicating the number of bytes received, and -1 on error.
-        return (ssize_t)data.length;
+        return (ssize_t)data_uint8.length;
     }
 
     private static int pull_timeout_function(void* transport_ptr, uint ms) {
-        DtlsSrtp self = transport_ptr as DtlsSrtp;
+        Handler self = transport_ptr as Handler;
 
         DateTime current_time = new DateTime.now_utc();
         current_time.add_seconds(ms/1000);
@@ -184,6 +223,10 @@ public class DtlsSrtp {
         self.buffer_mutex.lock();
         while (self.buffer_queue.size == 0) {
             self.buffer_cond.wait_until(self.buffer_mutex, end_time);
+            if (self.stop) {
+                self.buffer_mutex.unlock();
+                return -1;
+            }
 
             DateTime new_current_time = new DateTime.now_utc();
             if (new_current_time.compare(current_time) > 0) {
@@ -197,7 +240,7 @@ public class DtlsSrtp {
     }
 
     private static ssize_t push_function(void* transport_ptr, uint8[] buffer) {
-        DtlsSrtp self = transport_ptr as DtlsSrtp;
+        Handler self = transport_ptr as Handler;
         self.send_data(buffer);
 
         // The callback should return a positive number indicating the bytes sent, and -1 on error.
@@ -205,7 +248,7 @@ public class DtlsSrtp {
     }
 
     private static int verify_function(Session session) {
-        DtlsSrtp self = session.get_transport_pointer() as DtlsSrtp;
+        Handler self = session.get_transport_pointer() as Handler;
         try {
             bool valid = self.verify_peer_cert(session);
             if (!valid) {
@@ -232,7 +275,17 @@ public class DtlsSrtp {
         X509.Certificate peer_cert = X509.Certificate.create();
         peer_cert.import(ref cert_datums[0], CertificateFormat.DER);
 
-        uint8[] real_peer_fp = get_fingerprint(peer_cert, peer_fp_algo);
+        DigestAlgorithm algo;
+        switch (peer_fp_algo) {
+            case "sha-256":
+                algo = DigestAlgorithm.SHA256;
+                break;
+            default:
+                warning("Unkown peer fingerprint algorithm: %s", peer_fp_algo);
+                return false;
+        }
+
+        uint8[] real_peer_fp = get_fingerprint(peer_cert, algo);
 
         if (real_peer_fp.length != this.peer_fingerprint.length) {
             warning("Fingerprint lengths not equal %i vs %i", real_peer_fp.length, peer_fingerprint.length);
@@ -248,27 +301,34 @@ public class DtlsSrtp {
 
         return true;
     }
+}
 
-    private uint8[] get_fingerprint(X509.Certificate certificate, DigestAlgorithm digest_algo) {
-        uint8[] buf = new uint8[512];
-        size_t buf_out_size = 512;
-        certificate.get_fingerprint(digest_algo, buf, ref buf_out_size);
+private uint8[] get_fingerprint(X509.Certificate certificate, DigestAlgorithm digest_algo) {
+    uint8[] buf = new uint8[512];
+    size_t buf_out_size = 512;
+    certificate.get_fingerprint(digest_algo, buf, ref buf_out_size);
 
-        uint8[] ret = new uint8[buf_out_size];
-        for (int i = 0; i < buf_out_size; i++) {
-            ret[i] = buf[i];
-        }
-        return ret;
+    uint8[] ret = new uint8[buf_out_size];
+    for (int i = 0; i < buf_out_size; i++) {
+        ret[i] = buf[i];
     }
-
-    private string format_fingerprint(uint8[] fingerprint) {
-        var sb = new StringBuilder();
-        for (int i = 0; i < fingerprint.length; i++) {
-            sb.append("%02x".printf(fingerprint[i]));
-            if (i < fingerprint.length - 1) {
-                sb.append(":");
-            }
+    return ret;
+}
+
+private string format_fingerprint(uint8[] fingerprint) {
+    var sb = new StringBuilder();
+    for (int i = 0; i < fingerprint.length; i++) {
+        sb.append("%02x".printf(fingerprint[i]));
+        if (i < fingerprint.length - 1) {
+            sb.append(":");
         }
-        return sb.str;
     }
-}
\ No newline at end of file
+    return sb.str;
+}
+
+
+public enum Mode {
+    CLIENT, SERVER
+}
+
+}
diff --git a/plugins/ice/src/transport_parameters.vala b/plugins/ice/src/transport_parameters.vala
index f95be261..e4862edc 100644
--- a/plugins/ice/src/transport_parameters.vala
+++ b/plugins/ice/src/transport_parameters.vala
@@ -9,11 +9,11 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
     private bool we_want_connection;
     private bool remote_credentials_set;
     private Map<uint8, DatagramConnection> connections = new HashMap<uint8, DatagramConnection>();
-    private DtlsSrtp? dtls_srtp;
+    private DtlsSrtp.Handler? dtls_srtp_handler;
 
     private class DatagramConnection : Jingle.DatagramConnection {
         private Nice.Agent agent;
-        private DtlsSrtp? dtls_srtp;
+        private DtlsSrtp.Handler? dtls_srtp_handler;
         private uint stream_id;
         private string? error;
         private ulong sent;
@@ -22,9 +22,9 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
         private ulong recv_reported;
         private ulong datagram_received_id;
 
-        public DatagramConnection(Nice.Agent agent, DtlsSrtp? dtls_srtp, uint stream_id, uint8 component_id) {
+        public DatagramConnection(Nice.Agent agent, DtlsSrtp.Handler? dtls_srtp_handler, uint stream_id, uint8 component_id) {
             this.agent = agent;
-            this.dtls_srtp = dtls_srtp;
+            this.dtls_srtp_handler = dtls_srtp_handler;
             this.stream_id = stream_id;
             this.component_id = component_id;
             this.datagram_received_id = this.datagram_received.connect((datagram) => {
@@ -45,8 +45,8 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
         public override void send_datagram(Bytes datagram) {
             if (this.agent != null && is_component_ready(agent, stream_id, component_id)) {
                 uint8[] encrypted_data = null;
-                if (dtls_srtp != null) {
-                    encrypted_data = dtls_srtp.process_outgoing_data(component_id, datagram.get_data());
+                if (dtls_srtp_handler != null) {
+                    encrypted_data = dtls_srtp_handler.process_outgoing_data(component_id, datagram.get_data());
                     if (encrypted_data == null) return;
                 }
                 agent.send(stream_id, component_id, encrypted_data ?? datagram.get_data());
@@ -65,13 +65,18 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
         this.agent = agent;
 
         if (this.peer_fingerprint != null || !incoming) {
-            dtls_srtp = setup_dtls(this);
-            this.own_fingerprint = dtls_srtp.get_own_fingerprint(GnuTLS.DigestAlgorithm.SHA256);
+            dtls_srtp_handler = setup_dtls(this);
+            own_fingerprint = dtls_srtp_handler.own_fingerprint;
             if (incoming) {
-                dtls_srtp.set_peer_fingerprint(this.peer_fingerprint, this.peer_fp_algo == "sha-256" ? GnuTLS.DigestAlgorithm.SHA256 : GnuTLS.DigestAlgorithm.NULL);
+                own_setup = "active";
+                dtls_srtp_handler.mode = DtlsSrtp.Mode.CLIENT;
+                dtls_srtp_handler.peer_fingerprint = peer_fingerprint;
+                dtls_srtp_handler.peer_fp_algo = peer_fp_algo;
             } else {
-                dtls_srtp.setup_dtls_connection.begin(true, (_, res) => {
-                    this.content.encryption = dtls_srtp.setup_dtls_connection.end(res);
+                own_setup = "actpass";
+                dtls_srtp_handler.mode = DtlsSrtp.Mode.SERVER;
+                dtls_srtp_handler.setup_dtls_connection.begin((_, res) => {
+                    this.content.encryption = dtls_srtp_handler.setup_dtls_connection.end(res) ?? this.content.encryption;
                 });
             }
         }
@@ -104,9 +109,9 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
         agent.gather_candidates(stream_id);
     }
 
-    private static DtlsSrtp setup_dtls(TransportParameters tp) {
+    private static DtlsSrtp.Handler setup_dtls(TransportParameters tp) {
         var weak_self = new WeakRef(tp);
-        DtlsSrtp dtls_srtp = DtlsSrtp.setup();
+        DtlsSrtp.Handler dtls_srtp = DtlsSrtp.setup();
         dtls_srtp.send_data.connect((data) => {
             TransportParameters self = (TransportParameters) weak_self.get();
             if (self != null) self.agent.send(self.stream_id, 1, data);
@@ -144,10 +149,15 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
         debug("on_transport_accept from %s", peer_full_jid.to_string());
         base.handle_transport_accept(transport);
 
-        if (dtls_srtp != null && peer_fingerprint != null) {
-            dtls_srtp.set_peer_fingerprint(this.peer_fingerprint, this.peer_fp_algo == "sha-256" ? GnuTLS.DigestAlgorithm.SHA256 : GnuTLS.DigestAlgorithm.NULL);
+        if (dtls_srtp_handler != null && peer_fingerprint != null) {
+            dtls_srtp_handler.peer_fingerprint = peer_fingerprint;
+            dtls_srtp_handler.peer_fp_algo = peer_fp_algo;
+            if (peer_setup == "passive") {
+                dtls_srtp_handler.mode = DtlsSrtp.Mode.CLIENT;
+                dtls_srtp_handler.stop_dtls_connection();
+            }
         } else {
-            dtls_srtp = null;
+            dtls_srtp_handler = null;
         }
     }
 
@@ -200,18 +210,10 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
             int new_candidates = agent.set_remote_candidates(stream_id, i, candidates);
             debug("Initiated component %u with %i remote candidates", i, new_candidates);
 
-            connections[i] = new DatagramConnection(agent, dtls_srtp, stream_id, i);
+            connections[i] = new DatagramConnection(agent, dtls_srtp_handler, stream_id, i);
             content.set_transport_connection(connections[i], i);
         }
 
-        if (incoming && dtls_srtp != null) {
-            Jingle.DatagramConnection rtp_datagram = (Jingle.DatagramConnection) content.get_transport_connection(1);
-            rtp_datagram.notify["ready"].connect(() => {
-                dtls_srtp.setup_dtls_connection.begin(false, (_, res) => {
-                    this.content.encryption = dtls_srtp.setup_dtls_connection.end(res);
-                });
-            });
-        }
         base.create_transport_connection(stream, content);
     }
 
@@ -219,11 +221,16 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
         if (stream_id != this.stream_id) return;
         debug("stream %u component %u state changed to %s", stream_id, component_id, agent.get_component_state(stream_id, component_id).to_string());
         may_consider_ready(stream_id, component_id);
+        if (incoming && dtls_srtp_handler != null && !dtls_srtp_handler.ready && is_component_ready(agent, stream_id, component_id) && dtls_srtp_handler.mode == DtlsSrtp.Mode.CLIENT) {
+            dtls_srtp_handler.setup_dtls_connection.begin((_, res) => {
+                this.content.encryption = dtls_srtp_handler.setup_dtls_connection.end(res) ?? this.content.encryption;
+            });
+        }
     }
 
     private void may_consider_ready(uint stream_id, uint component_id) {
         if (stream_id != this.stream_id) return;
-        if (connections.has_key((uint8) component_id) && is_component_ready(agent, stream_id, component_id) && connections.has_key((uint8) component_id) && !connections[(uint8)component_id].ready) {
+        if (connections.has_key((uint8) component_id) && !connections[(uint8)component_id].ready && is_component_ready(agent, stream_id, component_id) && (dtls_srtp_handler == null || dtls_srtp_handler.ready)) {
             connections[(uint8)component_id].ready = true;
         }
     }
@@ -241,8 +248,8 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
     private void on_recv(Nice.Agent agent, uint stream_id, uint component_id, uint8[] data) {
         if (stream_id != this.stream_id) return;
         uint8[] decrypt_data = null;
-        if (dtls_srtp != null) {
-            decrypt_data = dtls_srtp.process_incoming_data(component_id, data);
+        if (dtls_srtp_handler != null) {
+            decrypt_data = dtls_srtp_handler.process_incoming_data(component_id, data);
             if (decrypt_data == null) return;
         }
         may_consider_ready(stream_id, component_id);
@@ -317,4 +324,4 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
 
         return candidate;
     }
-}
\ No newline at end of file
+}