[ADDED] TLS: natsOptions_SetTLSHandshakeFirst()

This is to force a client to perform the TLS handshake first, that
is, not wait for the INFO protocol from the server. This is needed
if the server is configured to require clients to perform the TLS
handshake first (before sending the INFO protocol).

Resolves #779

Signed-off-by: Ivan Kozlovic <[email protected]>

src/conn.c

@@ -786,7 +786,12 @@ _checkForSecure(natsConnection *nc)
     }
 
     if ((s == NATS_OK) && nc->opts->secure)
-        s = _makeTLSConn(nc);
+    {
+        // If TLS handshake first is true, we have already done
+        // the handshake, so do it only if false.
+        if (!nc->opts->tlsHandshakeFirst)
+            s = _makeTLSConn(nc);
+    }
 
     return NATS_UPDATE_ERR_STACK(s);
 }
@@ -1968,8 +1973,14 @@ _processConnInit(natsConnection *nc)
 
     nc->status = NATS_CONN_STATUS_CONNECTING;
 
+    // If we need to have a TLS connection and want the TLS handshake to occur
+    // first, do it now.
+    if (nc->opts->secure && nc->opts->tlsHandshakeFirst)
+        s = _makeTLSConn(nc);
+
     // Process the INFO protocol that we should be receiving
-    s = _processExpectedInfo(nc);
+    if (s == NATS_OK)
+        s = _processExpectedInfo(nc);
 
     // Send the CONNECT and PING protocol, and wait for the PONG.
     if (s == NATS_OK)
@@ -3280,6 +3291,11 @@ natsConn_create(natsConnection **newConn, natsOptions *options)
     nc->sockCtx.fd  = NATS_SOCK_INVALID;
     nc->opts        = options;
 
+    // If the TLSHandshakeFirst option is specified, make sure that
+    // the Secure boolean is true.
+    if (nc->opts->tlsHandshakeFirst)
+        nc->opts->secure = true;
+
     nc->errStr[0] = '\0';
 
     s = natsMutex_Create(&(nc->mu));

src/nats.h

@@ -1043,7 +1043,7 @@ typedef struct jsConsumerNamesList
  */
 typedef struct jsConsumerPauseResponse
 {
-        bool            Paused;        
+        bool            Paused;
         int64_t         PauseUntil;     ///< UTC time expressed as number of nanoseconds since epoch.
         int64_t         PauseRemaining; ///< Remaining time in nanoseconds.
 } jsConsumerPauseResponse;
@@ -2327,6 +2327,23 @@ natsOptions_SetName(natsOptions *opts, const char *name);
 NATS_EXTERN natsStatus
 natsOptions_SetSecure(natsOptions *opts, bool secure);
 
+/** \brief Performs TLS handshake first.
+ *
+ * If the server is not configured to require the client to perform
+ * the TLS handshake first, the server sends an INFO protocol first.
+ * When receiving it, the client and server are then initiate the
+ * TLS handshake.
+ *
+ * If the server is configured to require the client to perform
+ * the TLS handshake first, the client will fail to connect if
+ * not setting this option. Conversely, if the client is configured
+ * with this option but the server is not, the connection will fail.
+ *
+ * @param opts the pointer to the #natsOptions object.
+ */
+NATS_EXTERN natsStatus
+natsOptions_TLSHandshakeFirst(natsOptions *opts);
+
 /** \brief Loads the trusted CA certificates from a file.
  *
  * Loads the trusted CA certificates from a file.
@@ -4039,7 +4056,7 @@ natsConnection_Connect(natsConnection **nc, natsOptions *options);
  * This means that all subscriptions and consumers should be resubscribed and
  * their work resumed after successful reconnect where all reconnect options are
  * respected.
- * 
+ *
  * @param nc the pointer to the #natsConnection object.
  */
 natsStatus

src/natsp.h

@@ -224,6 +224,7 @@ struct __natsOptions
     bool                    pedantic;
     bool                    allowReconnect;
     bool                    secure;
+    bool                    tlsHandshakeFirst;
     int                     ioBufSize;
     int                     maxReconnect;
     int64_t                 reconnectWait;

src/opts.c

@@ -363,6 +363,21 @@ natsOptions_SetSecure(natsOptions *opts, bool secure)
     return NATS_UPDATE_ERR_STACK(s);
 }
 
+natsStatus
+natsOptions_TLSHandshakeFirst(natsOptions *opts)
+{
+    natsStatus s = NATS_OK;
+
+    LOCK_AND_CHECK_OPTIONS(opts, 0);
+
+    opts->tlsHandshakeFirst = true;
+    opts->secure            = true;
+
+    UNLOCK_OPTS(opts);
+
+    return NATS_UPDATE_ERR_STACK(s);
+}
+
 natsStatus
 natsOptions_LoadCATrustedCertificates(natsOptions *opts, const char *fileName)
 {
@@ -689,6 +704,12 @@ natsOptions_SetSecure(natsOptions *opts, bool secure)
     return nats_setError(NATS_ILLEGAL_STATE, "%s", NO_SSL_ERR);
 }
 
+natsStatus
+natsOptions_TLSHandshakeFirst(natsOptions *opts)
+{
+    return nats_setError(NATS_ILLEGAL_STATE, "%s", NO_SSL_ERR);
+}
+
 natsStatus
 natsOptions_LoadCATrustedCertificates(natsOptions *opts, const char *fileName)
 {

test/list_test.txt

@@ -246,6 +246,7 @@ _test(SSLBasic)
 _test(SSLCertAndKeyFromMemory)
 _test(SSLCiphers)
 _test(SSLConnectVerboseOption)
+_test(SSLHandshakeFirst)
 _test(SSLLoadCAFromMemory)
 _test(SSLMultithreads)
 _test(SSLReconnectWithAuthError)

test/test.c

@@ -2614,7 +2614,8 @@ void test_natsOptions(void)
              && (opts->writeDeadline == natsLib_defaultWriteDeadline())
              && !opts->noEcho
              && !opts->retryOnFailedConnect
-             && !opts->ignoreDiscoveredServers)
+             && !opts->ignoreDiscoveredServers
+             && !opts->tlsHandshakeFirst);
 
     test("Add URL: ");
     s = natsOptions_SetURL(opts, "test");
@@ -2764,6 +2765,14 @@ void test_natsOptions(void)
     testCond((s == NATS_ILLEGAL_STATE) && (opts->secure == false));
 #endif
 
+    test("Set TLSHandshakeFirst: ");
+    s = natsOptions_TLSHandshakeFirst(opts);
+#if defined(NATS_HAS_TLS)
+    testCond((s == NATS_OK) && (opts->tlsHandshakeFirst == true) && (opts->secure == true));
+#else
+    testCond((s == NATS_ILLEGAL_STATE) && (opts->secure == false) && (opts->tlsHandshakeFirst == false));
+#endif
+
     test("Set Pedantic: ");
     s = natsOptions_SetPedantic(opts, true);
     testCond((s == NATS_OK) && (opts->pedantic == true));
@@ -21197,6 +21206,62 @@ void test_SSLConnectVerboseOption(void)
 #endif
 }
 
+void test_SSLHandshakeFirst(void)
+{
+#if defined(NATS_HAS_TLS)
+    natsStatus          s;
+    natsConnection      *nc       = NULL;
+    natsOptions         *opts     = NULL;
+    natsPid             serverPid = NATS_INVALID_PID;
+
+    serverPid = _startServer("nats://127.0.0.1:4443", "-config tlsfirst.conf", true);
+    CHECK_SERVER_STARTED(serverPid);
+
+    test("Set options: ");
+    s = natsOptions_Create(&opts);
+    IFOK(s, natsOptions_SetURL(opts, "nats://127.0.0.1:4443"));
+    IFOK(s, natsOptions_SetSecure(opts, true));
+    IFOK(s, natsOptions_SkipServerVerification(opts, true));
+    IFOK(s, natsOptions_SetTimeout(opts, 500));
+    testCond(s == NATS_OK);
+
+    test("Check that connect fails if option not set: ");
+    s = natsConnection_Connect(&nc, opts);
+    testCond(s != NATS_OK);
+    nats_clearLastError();
+
+    test("Set TLSHandshakeFirst option error: ");
+    s = natsOptions_TLSHandshakeFirst(NULL);
+    testCond(s == NATS_INVALID_ARG);
+    nats_clearLastError();
+
+    test("Set TLSHandshakeFirst option: ");
+    s = natsOptions_TLSHandshakeFirst(opts);
+    testCond(s == NATS_OK);
+
+    test("Check that connect succeeds: ");
+    s = natsConnection_Connect(&nc, opts);
+    testCond(s == NATS_OK);
+    natsConnection_Destroy(nc);
+    nc = NULL;
+
+    _stopServer(serverPid);
+    serverPid = _startServer("nats://127.0.0.1:4443", "-config tls.conf", true);
+    CHECK_SERVER_STARTED(serverPid);
+
+    test("Check that connect fails if option is set but not in the server: ");
+    s = natsConnection_Connect(&nc, opts);
+    testCond(s != NATS_OK);
+    nats_clearLastError();
+
+    natsOptions_Destroy(opts);
+
+#else
+    test("Skipped when built with no SSL support: ");
+    testCond(true);
+#endif
+}
+
 #if defined(NATS_HAS_TLS)
 static natsStatus
 _elDummyAttach(void **userData, void *loop, natsConnection *nc, natsSock socket) { return NATS_OK; }

test/tlsfirst.conf

@@ -0,0 +1,16 @@
+
+# Simple TLS config file
+
+port: 4443
+net: "0.0.0.0"
+
+tls {
+  # Server cert
+  cert_file: "certs/server-cert.pem"
+  # Server private key
+  key_file:  "certs/server-key.pem"
+  # Increase timeout for valgrind tests
+  timeout: 2
+  # Force client to do the handshake first
+  handshake_first: true
+}