shaka-packager/packager/media/base/playready_key_source.cc

225 lines
8.1 KiB
C++

// Copyright 2017 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#include <packager/media/base/playready_key_source.h>
#include <algorithm>
#include <iterator>
#include <absl/strings/escaping.h>
#include <glog/logging.h>
#include <packager/media/base/buffer_writer.h>
#include <packager/media/base/http_key_fetcher.h>
#include <packager/media/base/key_source.h>
#include <packager/media/base/protection_system_ids.h>
#include <packager/status/status_macros.h>
#include <packager/utils/hex_parser.h>
namespace shaka {
namespace media {
namespace {
const int32_t kHttpFetchTimeout = 60; // In seconds
const std::string kAcquireLicenseRequest =
"<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
"<soap:Envelope xmlns=\"http://schemas.xmlsoap.org/soap/envelope/\" "
"xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" "
"xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" "
"xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">"
"<soap:Body>"
"<AcquirePackagingData "
"xmlns=\"http://schemas.microsoft.com/DRM/2007/03/protocols\">"
"<challenge "
"xmlns=\"http://schemas.microsoft.com/DRM"
"/2007/03/protocols/AcquirePackagingData/v1.0\">"
"<ProtectionSystems>"
"<ProtectionSystemId>9A04F079-9840-4286-AB92-E65BE0885F95"
"</ProtectionSystemId>"
"</ProtectionSystems>"
"<StreamProtectionRequests>"
"<StreamInformation>"
"<ProgramIdentifier>$0</ProgramIdentifier>"
"<OffsetFromProgramStart>P0S</OffsetFromProgramStart>"
"</StreamInformation>"
"</StreamProtectionRequests>"
"</challenge>"
"</AcquirePackagingData>"
"</soap:Body>"
"</soap:Envelope>";
bool Base64StringToBytes(const std::string& base64_string,
std::vector<uint8_t>* bytes) {
DCHECK(bytes);
std::string str;
if (!absl::Base64Unescape(base64_string, &str))
return false;
bytes->assign(str.begin(), str.end());
return true;
}
}
PlayReadyKeySource::PlayReadyKeySource(const std::string& server_url,
ProtectionSystem protection_systems)
// PlayReady PSSH is retrived from PlayReady server response.
: generate_playready_protection_system_(
// Generate PlayReady protection system if there are no other
// protection system specified.
protection_systems == ProtectionSystem::kNone ||
has_flag(protection_systems, ProtectionSystem::kPlayReady)),
encryption_key_(new EncryptionKey),
server_url_(server_url) {}
PlayReadyKeySource::~PlayReadyKeySource() = default;
Status RetrieveTextInXMLElement(const std::string& element,
const std::string& xml,
std::string* value) {
std::string start_tag = "<" + element + ">";
std::string end_tag = "</" + element + ">";
std::size_t start_pos = xml.find(start_tag);
if (start_pos == std::string::npos) {
return Status(error::SERVER_ERROR,
"Unable to find tag: " + start_tag);
}
start_pos += start_tag.size();
std::size_t end_pos = xml.find(end_tag);
if (end_pos == std::string::npos) {
return Status(error::SERVER_ERROR,
"Unable to find tag: " + end_tag);
}
if (start_pos > end_pos) {
return Status(error::SERVER_ERROR, "Invalid positions");
}
std::size_t segment_len = end_pos - start_pos;
*value = xml.substr(start_pos, segment_len);
return Status::OK;
}
Status SetKeyInformationFromServerResponse(
const std::string& response,
bool generate_playready_protection_system,
EncryptionKey* encryption_key) {
// TODO(robinconnell): Currently all tracks are encrypted using the same
// key_id and key. Add the ability to retrieve multiple key_id/keys from
// the packager response and encrypt multiple tracks using differnt
// key_id/keys.
std::string key_id_hex;
RETURN_IF_ERROR(RetrieveTextInXMLElement("KeyId", response, &key_id_hex));
key_id_hex.erase(
std::remove(key_id_hex.begin(), key_id_hex.end(), '-'), key_id_hex.end());
std::string key_id_raw;
if (!ValidHexStringToBytes(key_id_hex, &key_id_raw)) {
LOG(ERROR) << "Cannot parse key_id_hex, " << key_id_hex;
return Status(error::SERVER_ERROR, "Cannot parse key_id_hex.");
}
encryption_key->key_id.assign(key_id_raw.begin(), key_id_raw.end());
std::string key_data_b64;
RETURN_IF_ERROR(RetrieveTextInXMLElement("KeyData", response, &key_data_b64));
if (!Base64StringToBytes(key_data_b64, &encryption_key->key)) {
LOG(ERROR) << "Cannot parse key, " << key_data_b64;
return Status(error::SERVER_ERROR, "Cannot parse key.");
}
encryption_key->key_ids.emplace_back(encryption_key->key_id);
if (generate_playready_protection_system) {
std::string pssh_data_b64;
RETURN_IF_ERROR(RetrieveTextInXMLElement("Data", response, &pssh_data_b64));
std::vector<uint8_t> pssh_data;
if (!Base64StringToBytes(pssh_data_b64, &pssh_data)) {
LOG(ERROR) << "Cannot parse pssh data, " << pssh_data_b64;
return Status(error::SERVER_ERROR, "Cannot parse pssh.");
}
PsshBoxBuilder pssh_builder;
pssh_builder.add_key_id(encryption_key->key_id);
pssh_builder.set_system_id(kPlayReadySystemId,
std::size(kPlayReadySystemId));
pssh_builder.set_pssh_data(pssh_data);
encryption_key->key_system_info.push_back(
{pssh_builder.system_id(), pssh_builder.CreateBox()});
}
return Status::OK;
}
Status PlayReadyKeySource::FetchKeysWithProgramIdentifier(
const std::string& program_identifier) {
std::unique_ptr<EncryptionKey> encryption_key(new EncryptionKey);
HttpKeyFetcher key_fetcher(kHttpFetchTimeout);
std::string acquire_license_request = kAcquireLicenseRequest;
// Replace "$0" with |program_identifier|
size_t dollar_zero_location = acquire_license_request.find("$0");
if (dollar_zero_location != std::string::npos) {
acquire_license_request.replace(dollar_zero_location, /* len= */ 2,
program_identifier);
}
std::string acquire_license_response;
Status status = key_fetcher.FetchKeys(server_url_, acquire_license_request,
&acquire_license_response);
VLOG(1) << "Server response: " << acquire_license_response;
RETURN_IF_ERROR(status);
RETURN_IF_ERROR(SetKeyInformationFromServerResponse(
acquire_license_response, generate_playready_protection_system_,
encryption_key.get()));
// PlayReady does not specify different streams.
encryption_key_ = std::move(encryption_key);
return Status::OK;
}
Status PlayReadyKeySource::FetchKeys(EmeInitDataType init_data_type,
const std::vector<uint8_t>& init_data) {
UNUSED(init_data_type);
UNUSED(init_data);
// Do nothing for PlayReady encryption/decryption.
return Status::OK;
}
Status PlayReadyKeySource::GetKey(const std::string& stream_label,
EncryptionKey* key) {
UNUSED(stream_label);
// TODO(robinconnell): Currently all tracks are encrypted using the same
// key_id and key. Add the ability to encrypt each stream_label using a
// different key_id and key.
DCHECK(key);
DCHECK(encryption_key_);
*key = *encryption_key_;
return Status::OK;
}
Status PlayReadyKeySource::GetKey(const std::vector<uint8_t>& key_id,
EncryptionKey* key) {
UNUSED(key_id);
// TODO(robinconnell): Currently all tracks are encrypted using the same
// key_id and key. Add the ability to encrypt using multiple key_id/keys.
DCHECK(key);
DCHECK(encryption_key_);
*key = *encryption_key_;
return Status::OK;
}
Status PlayReadyKeySource::GetCryptoPeriodKey(
uint32_t crypto_period_index,
int32_t crypto_period_duration_in_seconds,
const std::string& stream_label,
EncryptionKey* key) {
UNUSED(crypto_period_index);
UNUSED(crypto_period_duration_in_seconds);
UNUSED(stream_label);
// TODO(robinconnell): Implement key rotation.
*key = *encryption_key_;
return Status::OK;
}
} // namespace media
} // namespace shaka