Add FIDO U2F message and packet classes

device/u2f/u2f_packet.cc

Index: device/u2f/u2f_packet.cc
diff --git a/device/u2f/u2f_packet.cc b/device/u2f/u2f_packet.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4ce6397e28f316d943d5d79b58c2d1aaab8e186a
--- /dev/null
+++ b/device/u2f/u2f_packet.cc
@@ -0,0 +1,110 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <iostream>
+#include "device/u2f/u2f_packet.h"
+
+namespace device {
+
+U2fPacket::U2fPacket(const std::vector<uint8_t> data,
+                     const uint8_t channel_id[kChannelIdSize])
+    : data_(data) {
+  for (size_t index = 0; index < kChannelIdSize; ++index)
+    channel_id_[index] = channel_id[index];
+}
+
+U2fPacket::U2fPacket() : data_() {}
+
+U2fPacket::~U2fPacket() {}
+
+scoped_refptr<net::IOBufferWithSize> U2fPacket::GetBuffer() {
+  if (serialized_)
+    return serialized_;
+  else
+    return make_scoped_refptr(new net::IOBufferWithSize(0));
+}
+
+// U2F Initialization packet is defined as:
+// Offset Length
+// 0      4       Channel ID
+// 4      1       Command ID
+// 5      1       High order packet payload size
+// 6      1       Low order packet payload size
+// 7      (s-7)   Payload data
+U2fInitPacket::U2fInitPacket(const uint8_t channel_id[kChannelIdSize],
+                             const uint8_t cmd,
+                             const std::vector<uint8_t> data,
+                             const uint16_t payload_length)
+    : U2fPacket(data, channel_id), command_(cmd) {
+  serialized_ = new net::IOBufferWithSize(kPacketSize);
+  size_t index = 0;
+  serialized_->data()[index++] = 0;
+  for (size_t i = 0; i < kChannelIdSize; ++i, index++)
+    serialized_->data()[index] = channel_id_[i];
+
+  serialized_->data()[index++] = command_;
+
+  serialized_->data()[index++] = (payload_length >> 8) & 0xff;
+  serialized_->data()[index++] = payload_length & 0xff;
+  for (size_t data_idx = 0; data_idx < data_.size(); ++data_idx)
+    serialized_->data()[index++] = data_.at(data_idx);
+  while ((int)index < serialized_->size())

[Reilly Grant (use Gerrit), 2016/11/30 20:53:47]

static_cast<int>

[Casey Piper, 2016/11/30 22:05:46]

Done.

+    serialized_->data()[index++] = 0;
+}
+
+scoped_refptr<U2fInitPacket> U2fInitPacket::Create(
+    scoped_refptr<net::IOBufferWithSize> buf) {
+  if (!buf || buf->size() != kPacketSize)
+    return nullptr;
+
+  return make_scoped_refptr(new U2fInitPacket(buf));
+}
+
+U2fInitPacket::U2fInitPacket(scoped_refptr<net::IOBufferWithSize> buf)
+    : U2fPacket(), command_() {
+  size_t index = 1;
+  uint16_t payload_size = 0;
+
+  channel_id_[0] = buf->data()[index++];
+  channel_id_[1] = buf->data()[index++];
+  channel_id_[2] = buf->data()[index++];
+  channel_id_[3] = buf->data()[index++];
+  command_ = buf->data()[index++];
+  payload_size = ((uint16_t)buf->data()[index++]) << 8;
+  payload_size |= buf->data()[index++];
+  // Check to see if payload is smaller than maximum size
+  payload_size = (payload_size + index > kPacketSize) ? (kPacketSize - index)
+                                                      : payload_size;

[Reilly Grant (use Gerrit), 2016/11/30 20:53:47]

payload_size = std::min(payload_size, kPacketSize - index);

Though it seems safer to reject invalid packets.

[Casey Piper, 2016/11/30 22:05:46]

Yeah, it was poorly written. To clarify, for payload size, it is the size of the
total payload, which can be more than the total size of this particular packet
(or less). It might be my reuse of the payload_size variable that is also
confusing. I'm checking to see if there are going to be padded zeros in the
buffer, which I don't need when reconstructing the packet from a buffer. I'll
add an additional variable and add the std::min call.

+
+  data_.insert(std::end(data_), buf->data()[index],
+               buf->data()[index + payload_size]);
+}
+
+U2fInitPacket::~U2fInitPacket() {}
+
+// U2F Continuation packet is defined as:
+// Offset Length
+// 0      4       Channel ID
+// 4      1       Packet sequence 0x00..0x7f
+// 5      (s-5)   Payload data
+U2fContPacket::U2fContPacket(const uint8_t channel_id[kChannelIdSize],
+                             const uint8_t sequence,
+                             std::vector<uint8_t> data)
+    : U2fPacket(data, channel_id), sequence_(sequence) {
+  serialized_ = new net::IOBufferWithSize(kPacketSize);
+  size_t index = 0;
+  serialized_->data()[index++] = 0;
+  for (size_t idx = 0; idx < kChannelIdSize; ++idx)
+    serialized_->data()[index++] = channel_id_[idx];
+
+  serialized_->data()[index++] = sequence_;
+  for (size_t idx = 0; idx < data_.size(); ++idx)
+    serialized_->data()[index++] = data_.at(idx);
+
+  while ((int)index < serialized_->size())

[Reilly Grant (use Gerrit), 2016/11/30 20:53:47]

static_cast<int>

[Casey Piper, 2016/11/30 22:05:46]

Acknowledged.

+    serialized_->data()[index++] = 0;
+}
+
+U2fContPacket::~U2fContPacket() {}
+}  // namespace device