Use MIDIMessageQueue/IsValidWebMIDIData for MIDI byte stream validation

content/browser/renderer_host/media/midi_host.cc

Index: content/browser/renderer_host/media/midi_host.cc
diff --git a/content/browser/renderer_host/media/midi_host.cc b/content/browser/renderer_host/media/midi_host.cc
index 934d5a21f1839fa97a5740fc60d28bba1936a05a..26942504f223aff1f118f77d16452ccfc2544768 100644
--- a/content/browser/renderer_host/media/midi_host.cc
+++ b/content/browser/renderer_host/media/midi_host.cc
@@ -16,6 +16,7 @@
 #include "content/public/browser/media_observer.h"
 #include "content/public/browser/user_metrics.h"
 #include "media/midi/midi_manager.h"
+#include "media/midi/midi_message_queue.h"
 
 using media::MIDIManager;
 using media::MIDIPortInfoList;
@@ -75,6 +76,8 @@ void MIDIHost::OnStartSession(int client_id) {
     if (success) {
       input_ports = midi_manager_->input_ports();
       output_ports = midi_manager_->output_ports();
+      received_messages_queues_.clear();
+      received_messages_queues_.resize(input_ports.size());
     }
   }
 
@@ -130,20 +133,41 @@ void MIDIHost::ReceiveMIDIData(
     double timestamp) {
   TRACE_EVENT0("midi", "MIDIHost::ReceiveMIDIData");
 
-  // Check a process security policy to receive a system exclusive message.
-  if (length > 0 && data[0] >= kSysExMessage) {
-    if (!ChildProcessSecurityPolicyImpl::GetInstance()->CanSendMIDISysExMessage(
-        renderer_process_id_)) {
-      // MIDI devices may send a system exclusive messages even if the renderer
-      // doesn't have a permission to receive it. Don't kill the renderer as
-      // OnSendData() does.
-      return;
+  if (received_messages_queues_.size() <= port)
+    return;
+
+  // Lazy initialization
+  if (received_messages_queues_[port] == NULL)
+    received_messages_queues_[port] = new media::MIDIMessageQueue(true);
+
+  bool sys_ex_allowed = false;
+  bool sys_ex_allowed_initialized = false;
+
+  received_messages_queues_[port]->Add(data, length);
+  std::vector<uint8> message;
+  while (true) {
+    received_messages_queues_[port]->Get(&message);
+    if (message.empty())
+      break;
+
+    // MIDI devices may send a system exclusive messages even if the renderer
+    // doesn't have a permission to receive it. Don't kill the renderer as
+    // OnSendData() does.
+    if (message[0] == kSysExMessage) {

[yukawa, 2013/11/14 14:55:31]

This condition is slightly different from the previous one, which rejected not
only 0xf0 but also [0xf1, 0xff].  Please let me know if we should keep the
previous condition.

[Takashi Toyoshima, 2013/11/19 01:08:37]

I chatted this with Chris, and double checked that it's ok to pass non-sysex
0xf* messages here.
So your implementation is right.

+      // Lazily check if SysEx is allowed or not in case checking this is
+      // costly.
+      if (!sys_ex_allowed_initialized) {
+        sys_ex_allowed = ChildProcessSecurityPolicyImpl::GetInstance()->
+            CanSendMIDISysExMessage(renderer_process_id_);
+        sys_ex_allowed_initialized = true;
+      }
+      if (!sys_ex_allowed)
+        continue;
     }
-  }
 
-  // Send to the renderer.
-  std::vector<uint8> v(data, data + length);
-  Send(new MIDIMsg_DataReceived(port, v, timestamp));
+    // Send to the renderer.
+    Send(new MIDIMsg_DataReceived(port, message, timestamp));
+  }
 }
 
 void MIDIHost::AccumulateMIDIBytesSent(size_t n) {