device/usb/webusb_descriptors.cc - chromium/src - Git at Google

 // Copyright 2015 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 "device/usb/webusb_descriptors.h"

 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/stl_util.h"
 #include "components/device_event_log/device_event_log.h"
 #include "device/usb/usb_device_handle.h"

 namespace device {

 namespace {

 // These constants are defined by the Universal Serial Device 3.0 Specification
 // Revision 1.0.
 const uint8_t kGetDescriptorRequest = 0x06;

 const uint8_t kBosDescriptorType = 0x0F;
 const uint8_t kDeviceCapabilityDescriptorType = 0x10;

 const uint8_t kPlatformDevCapabilityType = 0x05;

 // These constants are defined by the WebUSB specification:
 // http://wicg.github.io/webusb/
 const uint8_t kGetUrlRequest = 0x02;

 const uint8_t kWebUsbCapabilityUUID[16] = {
     // Little-endian encoding of {3408b638-09a9-47a0-8bfd-a0768815b665}.
     0x38, 0xB6, 0x08, 0x34, 0xA9, 0x09, 0xA0, 0x47,
     0x8B, 0xFD, 0xA0, 0x76, 0x88, 0x15, 0xB6, 0x65};

 const int kControlTransferTimeoutMs = 2000;  // 2 seconds

 using ReadWebUsbDescriptorsCallback =
     base::Callback<void(const GURL& landing_page)>;

 void OnReadLandingPage(uint8_t landing_page_id,
                        const ReadWebUsbDescriptorsCallback& callback,
                        UsbTransferStatus status,
                        scoped_refptr<base::RefCountedBytes> buffer,
                        size_t length) {
   if (status != UsbTransferStatus::COMPLETED) {
     USB_LOG(EVENT) << "Failed to read WebUSB URL descriptor: "
                    << static_cast<int>(landing_page_id);
     callback.Run(GURL());
     return;
   }

   GURL url;
   ParseWebUsbUrlDescriptor(
       std::vector<uint8_t>(buffer->front(), buffer->front() + length), &url);
   callback.Run(url);
 }

 void ReadLandingPage(uint8_t vendor_code,
                      uint8_t landing_page_id,
                      scoped_refptr<UsbDeviceHandle> device_handle,
                      const ReadWebUsbDescriptorsCallback& callback) {
   auto buffer = base::MakeRefCounted<base::RefCountedBytes>(255);
   device_handle->ControlTransfer(
       UsbTransferDirection::INBOUND, UsbControlTransferType::VENDOR,
       UsbControlTransferRecipient::DEVICE, vendor_code, landing_page_id,
       kGetUrlRequest, buffer, kControlTransferTimeoutMs,
       base::BindOnce(&OnReadLandingPage, landing_page_id, callback));
 }

 void OnReadBosDescriptor(scoped_refptr<UsbDeviceHandle> device_handle,
                          const ReadWebUsbDescriptorsCallback& callback,
                          UsbTransferStatus status,
                          scoped_refptr<base::RefCountedBytes> buffer,
                          size_t length) {
   if (status != UsbTransferStatus::COMPLETED) {
     USB_LOG(EVENT) << "Failed to read BOS descriptor.";
     callback.Run(GURL());
     return;
   }

   WebUsbPlatformCapabilityDescriptor descriptor;
   if (!descriptor.ParseFromBosDescriptor(
           std::vector<uint8_t>(buffer->front(), buffer->front() + length))) {
     callback.Run(GURL());
     return;
   }

   if (descriptor.landing_page_id) {
     ReadLandingPage(descriptor.vendor_code, descriptor.landing_page_id,
                     device_handle, callback);
   } else {
     callback.Run(GURL());
   }
 }

 void OnReadBosDescriptorHeader(scoped_refptr<UsbDeviceHandle> device_handle,
                                const ReadWebUsbDescriptorsCallback& callback,
                                UsbTransferStatus status,
                                scoped_refptr<base::RefCountedBytes> buffer,
                                size_t length) {
   if (status != UsbTransferStatus::COMPLETED || length != 5) {
     USB_LOG(EVENT) << "Failed to read BOS descriptor header.";
     callback.Run(GURL());
     return;
   }

   const uint8_t* data = buffer->front();
   uint16_t new_length = data[2] | (data[3] << 8);
   auto new_buffer = base::MakeRefCounted<base::RefCountedBytes>(new_length);
   device_handle->ControlTransfer(
       UsbTransferDirection::INBOUND, UsbControlTransferType::STANDARD,
       UsbControlTransferRecipient::DEVICE, kGetDescriptorRequest,
       kBosDescriptorType << 8, 0, new_buffer, kControlTransferTimeoutMs,
       base::BindOnce(&OnReadBosDescriptor, device_handle, callback));
 }

 }  // namespace

 WebUsbPlatformCapabilityDescriptor::WebUsbPlatformCapabilityDescriptor()
     : version(0), vendor_code(0) {}

 WebUsbPlatformCapabilityDescriptor::~WebUsbPlatformCapabilityDescriptor() =
     default;

 bool WebUsbPlatformCapabilityDescriptor::ParseFromBosDescriptor(
     const std::vector<uint8_t>& bytes) {
   if (bytes.size() < 5) {
     // Too short for the BOS descriptor header.
     return false;
   }

   // Validate the BOS descriptor, defined in Table 9-12 of the Universal Serial
   // Bus 3.1 Specification, Revision 1.0.
   uint16_t total_length = bytes[2] + (bytes[3] << 8);
   if (bytes[0] != 5 ||                                    // bLength
       bytes[1] != kBosDescriptorType ||                   // bDescriptorType
       5 > total_length || total_length > bytes.size()) {  // wTotalLength
     return false;
   }

   uint8_t num_device_caps = bytes[4];
   auto it = bytes.begin();
   auto end = it + total_length;
   std::advance(it, 5);

   uint8_t length = 0;
   for (size_t i = 0; i < num_device_caps; ++i, std::advance(it, length)) {
     if (it == end) {
       return false;
     }

     // Validate the Device Capability descriptor, defined in Table 9-13 of the
     // Universal Serial Bus 3.1 Specification, Revision 1.0.
     length = it[0];
     if (length < 3 || std::distance(it, end) < length ||  // bLength
         it[1] != kDeviceCapabilityDescriptorType) {       // bDescriptorType
       return false;
     }

     if (it[2] != kPlatformDevCapabilityType) {  // bDevCapabilityType
       continue;
     }

     // Validate the Platform Capability Descriptor, defined in Table 9-18 of the
     // Universal Serial Bus 3.1 Specification, Revision 1.0.
     if (length < 20) {
       // Platform capability descriptors must be at least 20 bytes.
       return false;
     }

     if (memcmp(&it[4], kWebUsbCapabilityUUID, sizeof(kWebUsbCapabilityUUID)) !=
         0) {  // PlatformCapabilityUUID
       continue;
     }

     if (length < 22) {
       // The WebUSB capability descriptor must be at least 22 bytes (to allow
       // for future versions).
       return false;
     }

     version = it[20] + (it[21] << 8);  // bcdVersion
     if (version < 0x0100) {
       continue;
     }

     // Version 1.0 defines two fields for a total length of 24 bytes.
     if (length != 24) {
       return false;
     }

     vendor_code = it[22];
     landing_page_id = it[23];
     return true;
   }

   return false;
 }

 // Parses a WebUSB URL Descriptor:
 // http://wicg.github.io/webusb/#dfn-url-descriptor
 //
 //  0                   1                   2                   3
 //  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 // |     length    |     type      |    prefix     |    data[0]    |
 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 // |     data[1]   |      ...
 // +-+-+-+-+-+-+-+-+-+-+-+------
 bool ParseWebUsbUrlDescriptor(const std::vector<uint8_t>& bytes, GURL* output) {
   const uint8_t kDescriptorType = 0x03;
   const uint8_t kDescriptorMinLength = 3;

   if (bytes.size() < kDescriptorMinLength) {
     return false;
   }

   // Validate that the length is consistent and fits within the buffer.
   uint8_t length = bytes[0];
   if (length < kDescriptorMinLength || length > bytes.size() ||
       bytes[1] != kDescriptorType) {
     return false;
   }

   // Look up the URL prefix and append the rest of the data in the descriptor.
   std::string url;
   switch (bytes[2]) {
     case 0:
       url.append("http://");
       break;
     case 1:
       url.append("https://");
       break;
     default:
       return false;
   }
   url.append(reinterpret_cast<const char*>(bytes.data() + 3), length - 3);

   *output = GURL(url);
   if (!output->is_valid()) {
     return false;
   }

   return true;
 }

 void ReadWebUsbDescriptors(scoped_refptr<UsbDeviceHandle> device_handle,
                            const ReadWebUsbDescriptorsCallback& callback) {
   auto buffer = base::MakeRefCounted<base::RefCountedBytes>(5);
   device_handle->ControlTransfer(
       UsbTransferDirection::INBOUND, UsbControlTransferType::STANDARD,
       UsbControlTransferRecipient::DEVICE, kGetDescriptorRequest,
       kBosDescriptorType << 8, 0, buffer, kControlTransferTimeoutMs,
       base::BindOnce(&OnReadBosDescriptorHeader, device_handle, callback));
 }

 }  // namespace device
	// Copyright 2015 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 "device/usb/webusb_descriptors.h"

	#include "base/bind.h"
	#include "base/callback.h"
	#include "base/logging.h"
	#include "base/memory/ref_counted_memory.h"
	#include "base/stl_util.h"
	#include "components/device_event_log/device_event_log.h"
	#include "device/usb/usb_device_handle.h"

	namespace device {

	namespace {

	// These constants are defined by the Universal Serial Device 3.0 Specification
	// Revision 1.0.
	const uint8_t kGetDescriptorRequest = 0x06;

	const uint8_t kBosDescriptorType = 0x0F;
	const uint8_t kDeviceCapabilityDescriptorType = 0x10;

	const uint8_t kPlatformDevCapabilityType = 0x05;

	// These constants are defined by the WebUSB specification:
	// http://wicg.github.io/webusb/
	const uint8_t kGetUrlRequest = 0x02;

	const uint8_t kWebUsbCapabilityUUID[16] = {
	// Little-endian encoding of {3408b638-09a9-47a0-8bfd-a0768815b665}.
	0x38, 0xB6, 0x08, 0x34, 0xA9, 0x09, 0xA0, 0x47,
	0x8B, 0xFD, 0xA0, 0x76, 0x88, 0x15, 0xB6, 0x65};

	const int kControlTransferTimeoutMs = 2000; // 2 seconds

	using ReadWebUsbDescriptorsCallback =
	base::Callback<void(const GURL& landing_page)>;

	void OnReadLandingPage(uint8_t landing_page_id,
	const ReadWebUsbDescriptorsCallback& callback,
	UsbTransferStatus status,
	scoped_refptr<base::RefCountedBytes> buffer,
	size_t length) {
	if (status != UsbTransferStatus::COMPLETED) {
	USB_LOG(EVENT) << "Failed to read WebUSB URL descriptor: "
	<< static_cast<int>(landing_page_id);
	callback.Run(GURL());
	return;
	}

	GURL url;
	ParseWebUsbUrlDescriptor(
	std::vector<uint8_t>(buffer->front(), buffer->front() + length), &url);
	callback.Run(url);
	}

	void ReadLandingPage(uint8_t vendor_code,
	uint8_t landing_page_id,
	scoped_refptr<UsbDeviceHandle> device_handle,
	const ReadWebUsbDescriptorsCallback& callback) {
	auto buffer = base::MakeRefCounted<base::RefCountedBytes>(255);
	device_handle->ControlTransfer(
	UsbTransferDirection::INBOUND, UsbControlTransferType::VENDOR,
	UsbControlTransferRecipient::DEVICE, vendor_code, landing_page_id,
	kGetUrlRequest, buffer, kControlTransferTimeoutMs,
	base::BindOnce(&OnReadLandingPage, landing_page_id, callback));
	}

	void OnReadBosDescriptor(scoped_refptr<UsbDeviceHandle> device_handle,
	const ReadWebUsbDescriptorsCallback& callback,
	UsbTransferStatus status,
	scoped_refptr<base::RefCountedBytes> buffer,
	size_t length) {
	if (status != UsbTransferStatus::COMPLETED) {
	USB_LOG(EVENT) << "Failed to read BOS descriptor.";
	callback.Run(GURL());
	return;
	}

	WebUsbPlatformCapabilityDescriptor descriptor;
	if (!descriptor.ParseFromBosDescriptor(
	std::vector<uint8_t>(buffer->front(), buffer->front() + length))) {
	callback.Run(GURL());
	return;
	}

	if (descriptor.landing_page_id) {
	ReadLandingPage(descriptor.vendor_code, descriptor.landing_page_id,
	device_handle, callback);
	} else {
	callback.Run(GURL());
	}
	}

	void OnReadBosDescriptorHeader(scoped_refptr<UsbDeviceHandle> device_handle,
	const ReadWebUsbDescriptorsCallback& callback,
	UsbTransferStatus status,
	scoped_refptr<base::RefCountedBytes> buffer,
	size_t length) {
	if (status != UsbTransferStatus::COMPLETED \|\| length != 5) {
	USB_LOG(EVENT) << "Failed to read BOS descriptor header.";
	callback.Run(GURL());
	return;
	}

	const uint8_t* data = buffer->front();
	uint16_t new_length = data[2] \| (data[3] << 8);
	auto new_buffer = base::MakeRefCounted<base::RefCountedBytes>(new_length);
	device_handle->ControlTransfer(
	UsbTransferDirection::INBOUND, UsbControlTransferType::STANDARD,
	UsbControlTransferRecipient::DEVICE, kGetDescriptorRequest,
	kBosDescriptorType << 8, 0, new_buffer, kControlTransferTimeoutMs,
	base::BindOnce(&OnReadBosDescriptor, device_handle, callback));
	}

	} // namespace

	WebUsbPlatformCapabilityDescriptor::WebUsbPlatformCapabilityDescriptor()
	: version(0), vendor_code(0) {}

	WebUsbPlatformCapabilityDescriptor::~WebUsbPlatformCapabilityDescriptor() =
	default;

	bool WebUsbPlatformCapabilityDescriptor::ParseFromBosDescriptor(
	const std::vector<uint8_t>& bytes) {
	if (bytes.size() < 5) {
	// Too short for the BOS descriptor header.
	return false;
	}

	// Validate the BOS descriptor, defined in Table 9-12 of the Universal Serial
	// Bus 3.1 Specification, Revision 1.0.
	uint16_t total_length = bytes[2] + (bytes[3] << 8);
	if (bytes[0] != 5 \|\| // bLength
	bytes[1] != kBosDescriptorType \|\| // bDescriptorType
	5 > total_length \|\| total_length > bytes.size()) { // wTotalLength
	return false;
	}

	uint8_t num_device_caps = bytes[4];
	auto it = bytes.begin();
	auto end = it + total_length;
	std::advance(it, 5);

	uint8_t length = 0;
	for (size_t i = 0; i < num_device_caps; ++i, std::advance(it, length)) {
	if (it == end) {
	return false;
	}

	// Validate the Device Capability descriptor, defined in Table 9-13 of the
	// Universal Serial Bus 3.1 Specification, Revision 1.0.
	length = it[0];
	if (length < 3 \|\| std::distance(it, end) < length \|\| // bLength
	it[1] != kDeviceCapabilityDescriptorType) { // bDescriptorType
	return false;
	}

	if (it[2] != kPlatformDevCapabilityType) { // bDevCapabilityType
	continue;
	}

	// Validate the Platform Capability Descriptor, defined in Table 9-18 of the
	// Universal Serial Bus 3.1 Specification, Revision 1.0.
	if (length < 20) {
	// Platform capability descriptors must be at least 20 bytes.
	return false;
	}

	if (memcmp(&it[4], kWebUsbCapabilityUUID, sizeof(kWebUsbCapabilityUUID)) !=
	0) { // PlatformCapabilityUUID
	continue;
	}

	if (length < 22) {
	// The WebUSB capability descriptor must be at least 22 bytes (to allow
	// for future versions).
	return false;
	}

	version = it[20] + (it[21] << 8); // bcdVersion
	if (version < 0x0100) {
	continue;
	}

	// Version 1.0 defines two fields for a total length of 24 bytes.
	if (length != 24) {
	return false;
	}

	vendor_code = it[22];
	landing_page_id = it[23];
	return true;
	}

	return false;
	}

	// Parses a WebUSB URL Descriptor:
	// http://wicg.github.io/webusb/#dfn-url-descriptor
	//
	// 0 1 2 3
	// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	// \| length \| type \| prefix \| data[0] \|
	// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	// \| data[1] \| ...
	// +-+-+-+-+-+-+-+-+-+-+-+------
	bool ParseWebUsbUrlDescriptor(const std::vector<uint8_t>& bytes, GURL* output) {
	const uint8_t kDescriptorType = 0x03;
	const uint8_t kDescriptorMinLength = 3;

	if (bytes.size() < kDescriptorMinLength) {
	return false;
	}

	// Validate that the length is consistent and fits within the buffer.
	uint8_t length = bytes[0];
	if (length < kDescriptorMinLength \|\| length > bytes.size() \|\|
	bytes[1] != kDescriptorType) {
	return false;
	}

	// Look up the URL prefix and append the rest of the data in the descriptor.
	std::string url;
	switch (bytes[2]) {
	case 0:
	url.append("http://");
	break;
	case 1:
	url.append("https://");
	break;
	default:
	return false;
	}
	url.append(reinterpret_cast<const char*>(bytes.data() + 3), length - 3);

	*output = GURL(url);
	if (!output->is_valid()) {
	return false;
	}

	return true;
	}

	void ReadWebUsbDescriptors(scoped_refptr<UsbDeviceHandle> device_handle,
	const ReadWebUsbDescriptorsCallback& callback) {
	auto buffer = base::MakeRefCounted<base::RefCountedBytes>(5);
	device_handle->ControlTransfer(
	UsbTransferDirection::INBOUND, UsbControlTransferType::STANDARD,
	UsbControlTransferRecipient::DEVICE, kGetDescriptorRequest,
	kBosDescriptorType << 8, 0, buffer, kControlTransferTimeoutMs,
	base::BindOnce(&OnReadBosDescriptorHeader, device_handle, callback));
	}

	} // namespace device