nghttpx: Add TLSv1.3 0-RTT early data support

src/shrpx_connection.cc

@@ -60,7 +60,8 @@ Connection::Connection(struct ev_loop *loop, int fd, SSL *ssl,
                        IOCb readcb, TimerCb timeoutcb, void *data,
                        size_t tls_dyn_rec_warmup_threshold,
                        ev_tstamp tls_dyn_rec_idle_timeout, shrpx_proto proto)
-    : tls{DefaultMemchunks(mcpool), DefaultPeekMemchunks(mcpool)},
+    : tls{DefaultMemchunks(mcpool), DefaultPeekMemchunks(mcpool),
+          DefaultMemchunks(mcpool)},
       wlimit(loop, &wev, write_limit.rate, write_limit.burst),
       rlimit(loop, &rev, read_limit.rate, read_limit.burst, this),
       loop(loop),
@@ -120,10 +121,11 @@ void Connection::disconnect() {
     tls.warmup_writelen = 0;
     tls.last_writelen = 0;
     tls.last_readlen = 0;
-    tls.handshake_state = 0;
+    tls.handshake_state = TLS_CONN_NORMAL;
     tls.initial_handshake_done = false;
     tls.reneg_started = false;
     tls.sct_requested = false;
+    tls.early_data_finish = false;
   }
 
   if (fd != -1) {
@@ -141,7 +143,11 @@ void Connection::disconnect() {
   wlimit.stopw();
 }
 
-void Connection::prepare_client_handshake() { SSL_set_connect_state(tls.ssl); }
+void Connection::prepare_client_handshake() {
+  SSL_set_connect_state(tls.ssl);
+  // This prevents SSL_read_early_data from being called.
+  tls.early_data_finish = true;
+}
 
 void Connection::prepare_server_handshake() {
   SSL_set_accept_state(tls.ssl);
@@ -327,8 +333,9 @@ int Connection::tls_handshake() {
   wlimit.stopw();
   ev_timer_stop(loop, &wt);
 
+  std::array<uint8_t, 16_k> buf;
+
   if (ev_is_active(&rev)) {
-    std::array<uint8_t, 8_k> buf;
     auto nread = read_clear(buf.data(), buf.size());
     if (nread < 0) {
       if (LOG_ENABLED(INFO)) {
@@ -381,9 +388,59 @@ int Connection::tls_handshake() {
     break;
   }
 
+  int rv;
+
   ERR_clear_error();
 
-  auto rv = SSL_do_handshake(tls.ssl);
+#if OPENSSL_1_1_1_API
+  if (!tls.server_handshake || tls.early_data_finish) {
+    rv = SSL_do_handshake(tls.ssl);
+  } else {
+    for (;;) {
+      size_t nread;
+
+      rv = SSL_read_early_data(tls.ssl, buf.data(), buf.size(), &nread);
+      if (rv == SSL_READ_EARLY_DATA_ERROR) {
+        // If we have early data, and server sends ServerHello, assume
+        // that handshake is completed in server side, and start
+        // processing request.  If we don't exit handshake code here,
+        // server waits for EndOfEarlyData and Finished message from
+        // client, which voids the purpose of 0-RTT data.  The left
+        // over of handshake is done through write_tls or read_tls.
+        rv = (tls.handshake_state == TLS_CONN_WRITE_STARTED ||
+              tls.wbuf.rleft()) &&
+             tls.earlybuf.rleft();
+        break;
+      }
+
+      if (LOG_ENABLED(INFO)) {
+        LOG(INFO) << "tls: read early data " << nread << " bytes";
+      }
+
+      tls.earlybuf.append(buf.data(), nread);
+
+      if (rv == SSL_READ_EARLY_DATA_FINISH) {
+        if (LOG_ENABLED(INFO)) {
+          LOG(INFO) << "tls: read all early data; total "
+                    << tls.earlybuf.rleft() << " bytes";
+        }
+        tls.early_data_finish = true;
+        // The same reason stated above.
+        if ((tls.handshake_state == TLS_CONN_WRITE_STARTED ||
+             tls.wbuf.rleft()) &&
+            tls.earlybuf.rleft()) {
+          rv = 1;
+        } else {
+          ERR_clear_error();
+          rv = SSL_do_handshake(tls.ssl);
+        }
+        break;
+      }
+    }
+  }
+#else  // !OPENSSL_1_1_1_API
+  rv = SSL_do_handshake(tls.ssl);
+#endif // !OPENSSL_1_1_1_API
 
   if (rv <= 0) {
     auto err = SSL_get_error(tls.ssl, rv);
@@ -621,7 +678,21 @@ ssize_t Connection::write_tls(const void *data, size_t len) {
 
   ERR_clear_error();
 
+#if OPENSSL_1_1_1_API
+  int rv;
+  if (SSL_is_init_finished(tls.ssl)) {
+    rv = SSL_write(tls.ssl, data, len);
+  } else {
+    size_t nwrite;
+    rv = SSL_write_early_data(tls.ssl, data, len, &nwrite);
+    // Use the same semantics with SSL_write.
+    if (rv == 1) {
+      rv = nwrite;
+    }
+  }
+#else  // !OPENSSL_1_1_1_API
   auto rv = SSL_write(tls.ssl, data, len);
+#endif // !OPENSSL_1_1_1_API
 
   if (rv <= 0) {
     auto err = SSL_get_error(tls.ssl, rv);
@@ -656,6 +727,52 @@ ssize_t Connection::write_tls(const void *data, size_t len) {
 }
 
 ssize_t Connection::read_tls(void *data, size_t len) {
+  ERR_clear_error();
+
+#if OPENSSL_1_1_1_API
+  if (tls.earlybuf.rleft()) {
+    return tls.earlybuf.remove(data, len);
+  }
+  if (!tls.early_data_finish) {
+    // TLSv1.3 handshake is still going on.
+    size_t nread;
+    auto rv = SSL_read_early_data(tls.ssl, data, len, &nread);
+    if (rv == SSL_READ_EARLY_DATA_ERROR) {
+      auto err = SSL_get_error(tls.ssl, rv);
+      switch (err) {
+      case SSL_ERROR_WANT_READ:
+      case SSL_ERROR_WANT_WRITE: // TODO Probably not required.
+        return 0;
+      case SSL_ERROR_SSL:
+        if (LOG_ENABLED(INFO)) {
+          LOG(INFO) << "SSL_read: "
+                    << ERR_error_string(ERR_get_error(), nullptr);
+        }
+        return SHRPX_ERR_NETWORK;
+      default:
+        if (LOG_ENABLED(INFO)) {
+          LOG(INFO) << "SSL_read: SSL_get_error returned " << err;
+        }
+        return SHRPX_ERR_NETWORK;
+      }
+    }
+
+    if (LOG_ENABLED(INFO)) {
+      LOG(INFO) << "tls: read early data " << nread << " bytes";
+    }
+
+    if (rv == SSL_READ_EARLY_DATA_FINISH) {
+      if (LOG_ENABLED(INFO)) {
+        LOG(INFO) << "tls: read all early data";
+      }
+      tls.early_data_finish = true;
+      // We may have stopped write watcher in write_tls.
+      wlimit.startw();
+    }
+    return nread;
+  }
+#endif // OPENSSL_1_1_1_API
+
   // SSL_read requires the same arguments (buf pointer and its
   // length) on SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE.
   // rlimit_.avail() or rlimit_.avail() may return different length
@@ -673,8 +790,6 @@ ssize_t Connection::read_tls(void *data, size_t len) {
     tls.last_readlen = 0;
   }
 
-  ERR_clear_error();
-
   auto rv = SSL_read(tls.ssl, data, len);
 
   if (rv <= 0) {

src/shrpx_connection.h

@@ -56,6 +56,8 @@ enum {
 struct TLSConnection {
   DefaultMemchunks wbuf;
   DefaultPeekMemchunks rbuf;
+  // Stores TLSv1.3 early data.
+  DefaultMemchunks earlybuf;
   SSL *ssl;
   SSL_SESSION *cached_session;
   MemcachedRequest *cached_session_lookup_req;
@@ -74,6 +76,12 @@ struct TLSConnection {
   // true if ssl is initialized as server, and client requested
   // signed_certificate_timestamp extension.
   bool sct_requested;
+  // true if TLSv1.3 early data has been completely received.  Since
+  // SSL_read_early_data acts like SSL_do_handshake, this field may be
+  // true even if the negotiated TLS version is TLSv1.2 or earlier.
+  // This value is also true if this is client side connection for
+  // convenience.
+  bool early_data_finish;
 };
 
 struct TCPHint {

src/shrpx_rate_limit.cc

@@ -108,8 +108,9 @@ void RateLimit::stopw() {
 }
 
 void RateLimit::handle_tls_pending_read() {
-  if (!conn_ || !conn_->tls.ssl ||
+  if (!conn_ || !conn_->tls.ssl || !conn_->tls.initial_handshake_done ||
-      (SSL_pending(conn_->tls.ssl) == 0 && conn_->tls.rbuf.rleft() == 0)) {
+      (SSL_pending(conn_->tls.ssl) == 0 && conn_->tls.rbuf.rleft() == 0 &&
+       conn_->tls.earlybuf.rleft() == 0)) {
     return;
   }
 

src/shrpx_tls.cc

@@ -517,6 +517,13 @@ int ticket_key_cb(SSL *ssl, unsigned char *key_name, unsigned char *iv,
 
 namespace {
 void info_callback(const SSL *ssl, int where, int ret) {
+#ifdef TLS1_3_VERSION
+  // TLSv1.3 has no renegotiation.
+  if (SSL_version(ssl) == TLS1_3_VERSION) {
+    return;
+  }
+#endif // TLS1_3_VERSION
+
   // To mitigate possible DOS attack using lots of renegotiations, we
   // disable renegotiation. Since OpenSSL does not provide an easy way
   // to disable it, we check that renegotiation is started in this