PLAIN: Implement ERROR handling in client

src/plain_client.cpp

@@ -30,6 +30,7 @@
 
 zmq::plain_client_t::plain_client_t (const options_t &options_) :
     mechanism_t (options_),
+    error_command_received (false),
     state (sending_hello)
 {
 }
@@ -62,38 +63,45 @@ int zmq::plain_client_t::next_handshake_command (msg_t *msg_)
 
 int zmq::plain_client_t::process_handshake_command (msg_t *msg_)
 {
-    int rc = 0;
+    const unsigned char *cmd_data =
+        static_cast <unsigned char *> (msg_->data ());
+    const size_t data_size = msg_->size ();
 
-    switch (state) {
-        case waiting_for_welcome:
-            rc = process_welcome (msg_);
-            if (rc == 0)
-                state = sending_initiate;
-            break;
-        case waiting_for_ready:
-            rc = process_ready (msg_);
-            if (rc == 0)
-                state = ready;
-            break;
-        default:
-            //  Temporary support for security debugging
-            puts ("PLAIN I: invalid handshake command");
-            errno = EPROTO;
-            rc = -1;
-            break;
+    int rc = 0;
+    if (data_size >= 8 && !memcmp (cmd_data, "\7WELCOME", 8))
+        rc = process_welcome (cmd_data, data_size);
+    else
+    if (data_size >= 6 && !memcmp (cmd_data, "\5READY", 6))
+        rc = process_ready (cmd_data, data_size);
+    else
+    if (data_size >= 6 && !memcmp (cmd_data, "\5ERROR", 6))
+        rc = process_error (cmd_data, data_size);
+    else {
+        //  Temporary support for security debugging
+        puts ("PLAIN I: invalid handshake command");
+        errno = EPROTO;
+        rc = -1;
     }
+
     if (rc == 0) {
         rc = msg_->close ();
         errno_assert (rc == 0);
         rc = msg_->init ();
         errno_assert (rc == 0);
     }
+
     return rc;
 }
 
 zmq::mechanism_t::status_t zmq::plain_client_t::status () const
 {
-    return state == ready? mechanism_t::ready: mechanism_t::handshaking;
+    if (state == ready)
+        return mechanism_t::ready;
+    else
+    if (error_command_received)
+        return mechanism_t::error;
+    else
+        return mechanism_t::handshaking;
 }
 
 int zmq::plain_client_t::produce_hello (msg_t *msg_) const
@@ -125,17 +133,18 @@ int zmq::plain_client_t::produce_hello (msg_t *msg_) const
     return 0;
 }
 
-int zmq::plain_client_t::process_welcome (msg_t *msg_)
+int zmq::plain_client_t::process_welcome (
+        const unsigned char *cmd_data, size_t data_size)
 {
-    const unsigned char *ptr = static_cast <unsigned char *> (msg_->data ());
-    const size_t bytes_left = msg_->size ();
-
-    if (bytes_left != 8 ||  memcmp (ptr, "\x07WELCOME", 8)) {
-        //  Temporary support for security debugging
-        puts ("PLAIN I: invalid PLAIN client, did not send WELCOME");
+    if (state != waiting_for_welcome) {
         errno = EPROTO;
         return -1;
     }
+    if (data_size != 8) {
+        errno = EPROTO;
+        return -1;
+    }
+    state = sending_initiate;
     return 0;
 }
 
@@ -170,16 +179,35 @@ int zmq::plain_client_t::produce_initiate (msg_t *msg_) const
     return 0;
 }
 
-int zmq::plain_client_t::process_ready (msg_t *msg_)
+int zmq::plain_client_t::process_ready (
+        const unsigned char *cmd_data, size_t data_size)
 {
-    const unsigned char *ptr = static_cast <unsigned char *> (msg_->data ());
-    const size_t bytes_left = msg_->size ();
+    if (state != waiting_for_ready) {
+        errno = EPROTO;
+        return -1;
+    }
+    const int rc = parse_metadata (cmd_data + 6, data_size - 6);
+    if (rc == 0)
+        state = ready;
+    return rc;
+}
 
-    if (bytes_left < 6 || memcmp (ptr, "\x05READY", 6)) {
-        //  Temporary support for security debugging
-        puts ("PLAIN I: invalid PLAIN client, did not send READY");
+int zmq::plain_client_t::process_error (
+        const unsigned char *cmd_data, size_t data_size)
+{
+    if (state != waiting_for_welcome && state != waiting_for_ready) {
+        errno = EPROTO;
+        return -1;
+    }
+    if (data_size == 6) {
         errno = EPROTO;
         return -1;
     }
-    return parse_metadata (ptr + 6, bytes_left - 6);
+    const size_t size = static_cast <size_t> (cmd_data [6]);
+    if (6 + 1 + size != data_size) {
+        errno = EPROTO;
+        return -1;
+    }
+    error_command_received = true;
+    return 0;
 }

src/plain_client.hpp

@@ -42,6 +42,8 @@ namespace zmq
 
     private:
 
+        bool error_command_received;
+
         enum state_t {
             sending_hello,
             waiting_for_welcome,
@@ -55,8 +57,12 @@ namespace zmq
         int produce_hello (msg_t *msg_) const;
         int produce_initiate (msg_t *msg_) const;
 
-        int process_welcome (msg_t *msg);
-        int process_ready (msg_t *msg_);
+        int process_welcome (
+            const unsigned char *cmd_data, size_t data_size);
+        int process_ready (
+            const unsigned char *cmd_data, size_t data_size);
+        int process_error (
+            const unsigned char *cmd_data, size_t data_size);
     };
 
 }