438 lines
15 KiB
C++
438 lines
15 KiB
C++
// Copyright 2014 Google Inc. 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 "media/base/widevine_encryption_key_source.h"
|
|
|
|
#include "base/base64.h"
|
|
#include "base/bind.h"
|
|
#include "base/json/json_reader.h"
|
|
#include "base/json/json_writer.h"
|
|
#include "base/memory/ref_counted.h"
|
|
#include "base/stl_util.h"
|
|
#include "base/values.h"
|
|
#include "media/base/http_fetcher.h"
|
|
#include "media/base/request_signer.h"
|
|
|
|
#define RCHECK(x) \
|
|
do { \
|
|
if (!(x)) { \
|
|
LOG(ERROR) << "Failure while processing: " << #x; \
|
|
return false; \
|
|
} \
|
|
} while (0)
|
|
|
|
namespace {
|
|
|
|
const char kLicenseStatusOK[] = "OK";
|
|
// Server may return INTERNAL_ERROR intermittently, which is a transient error
|
|
// and the next client request may succeed without problem.
|
|
const char kLicenseStatusTransientError[] = "INTERNAL_ERROR";
|
|
|
|
// Number of times to retry requesting keys in case of a transient error from
|
|
// the server.
|
|
const int kNumTransientErrorRetries = 5;
|
|
const int kFirstRetryDelayMilliseconds = 1000;
|
|
|
|
// Default crypto period count, which is the number of keys to fetch on every
|
|
// key rotation enabled request.
|
|
const int kDefaultCryptoPeriodCount = 10;
|
|
const int kGetKeyTimeoutInSeconds = 5 * 60; // 5 minutes.
|
|
|
|
bool Base64StringToBytes(const std::string& base64_string,
|
|
std::vector<uint8>* bytes) {
|
|
DCHECK(bytes);
|
|
std::string str;
|
|
if (!base::Base64Decode(base64_string, &str))
|
|
return false;
|
|
bytes->assign(str.begin(), str.end());
|
|
return true;
|
|
}
|
|
|
|
bool GetKeyAndKeyId(const base::DictionaryValue& track_dict,
|
|
std::vector<uint8>* key,
|
|
std::vector<uint8>* key_id) {
|
|
DCHECK(key);
|
|
DCHECK(key_id);
|
|
|
|
std::string key_base64_string;
|
|
RCHECK(track_dict.GetString("key", &key_base64_string));
|
|
VLOG(2) << "Key:" << key_base64_string;
|
|
RCHECK(Base64StringToBytes(key_base64_string, key));
|
|
|
|
std::string key_id_base64_string;
|
|
RCHECK(track_dict.GetString("key_id", &key_id_base64_string));
|
|
VLOG(2) << "Keyid:" << key_id_base64_string;
|
|
RCHECK(Base64StringToBytes(key_id_base64_string, key_id));
|
|
|
|
return true;
|
|
}
|
|
|
|
bool GetPsshData(const base::DictionaryValue& track_dict,
|
|
std::vector<uint8>* pssh_data) {
|
|
DCHECK(pssh_data);
|
|
|
|
const base::ListValue* pssh_list;
|
|
RCHECK(track_dict.GetList("pssh", &pssh_list));
|
|
// Invariant check. We don't want to crash in release mode if possible.
|
|
// The following code handles it gracefully if GetSize() does not return 1.
|
|
DCHECK_EQ(1u, pssh_list->GetSize());
|
|
|
|
const base::DictionaryValue* pssh_dict;
|
|
RCHECK(pssh_list->GetDictionary(0, &pssh_dict));
|
|
std::string drm_type;
|
|
RCHECK(pssh_dict->GetString("drm_type", &drm_type));
|
|
if (drm_type != "WIDEVINE") {
|
|
LOG(ERROR) << "Expecting drm_type 'WIDEVINE', get '" << drm_type << "'.";
|
|
return false;
|
|
}
|
|
std::string pssh_data_base64_string;
|
|
RCHECK(pssh_dict->GetString("data", &pssh_data_base64_string));
|
|
|
|
VLOG(2) << "Pssh Data:" << pssh_data_base64_string;
|
|
RCHECK(Base64StringToBytes(pssh_data_base64_string, pssh_data));
|
|
return true;
|
|
}
|
|
|
|
} // namespace
|
|
|
|
namespace media {
|
|
|
|
// A ref counted wrapper for EncryptionKeyMap.
|
|
class WidevineEncryptionKeySource::RefCountedEncryptionKeyMap
|
|
: public base::RefCountedThreadSafe<RefCountedEncryptionKeyMap> {
|
|
public:
|
|
explicit RefCountedEncryptionKeyMap(EncryptionKeyMap* encryption_key_map) {
|
|
DCHECK(encryption_key_map);
|
|
encryption_key_map_.swap(*encryption_key_map);
|
|
}
|
|
|
|
std::map<EncryptionKeySource::TrackType, EncryptionKey*>& map() {
|
|
return encryption_key_map_;
|
|
}
|
|
|
|
private:
|
|
friend class base::RefCountedThreadSafe<RefCountedEncryptionKeyMap>;
|
|
|
|
~RefCountedEncryptionKeyMap() { STLDeleteValues(&encryption_key_map_); }
|
|
|
|
EncryptionKeyMap encryption_key_map_;
|
|
|
|
DISALLOW_COPY_AND_ASSIGN(RefCountedEncryptionKeyMap);
|
|
};
|
|
|
|
WidevineEncryptionKeySource::WidevineEncryptionKeySource(
|
|
const std::string& server_url,
|
|
const std::string& content_id,
|
|
scoped_ptr<RequestSigner> signer,
|
|
int first_crypto_period_index)
|
|
: http_fetcher_(new SimpleHttpFetcher()),
|
|
server_url_(server_url),
|
|
content_id_(content_id),
|
|
signer_(signer.Pass()),
|
|
key_rotation_enabled_(first_crypto_period_index >= 0),
|
|
crypto_period_count_(kDefaultCryptoPeriodCount),
|
|
first_crypto_period_index_(first_crypto_period_index),
|
|
key_production_thread_(
|
|
"KeyProductionThread",
|
|
base::Bind(&WidevineEncryptionKeySource::FetchKeysTask,
|
|
base::Unretained(this))),
|
|
key_pool_(kDefaultCryptoPeriodCount,
|
|
key_rotation_enabled_ ? first_crypto_period_index : 0) {
|
|
DCHECK(signer_);
|
|
key_production_thread_.Start();
|
|
}
|
|
|
|
WidevineEncryptionKeySource::~WidevineEncryptionKeySource() {
|
|
key_pool_.Stop();
|
|
key_production_thread_.Join();
|
|
}
|
|
|
|
Status WidevineEncryptionKeySource::GetKey(TrackType track_type,
|
|
EncryptionKey* key) {
|
|
DCHECK(!key_rotation_enabled_);
|
|
return GetKeyInternal(0u, track_type, key);
|
|
}
|
|
|
|
Status WidevineEncryptionKeySource::GetCryptoPeriodKey(
|
|
uint32 crypto_period_index,
|
|
TrackType track_type,
|
|
EncryptionKey* key) {
|
|
DCHECK(key_rotation_enabled_);
|
|
return GetKeyInternal(crypto_period_index, track_type, key);
|
|
}
|
|
|
|
void WidevineEncryptionKeySource::set_http_fetcher(
|
|
scoped_ptr<HttpFetcher> http_fetcher) {
|
|
http_fetcher_ = http_fetcher.Pass();
|
|
}
|
|
|
|
Status WidevineEncryptionKeySource::GetKeyInternal(
|
|
uint32 crypto_period_index,
|
|
TrackType track_type,
|
|
EncryptionKey* key) {
|
|
DCHECK_LE(track_type, NUM_VALID_TRACK_TYPES);
|
|
DCHECK_NE(track_type, TRACK_TYPE_UNKNOWN);
|
|
|
|
scoped_refptr<RefCountedEncryptionKeyMap> ref_counted_encryption_key_map;
|
|
Status status = key_pool_.Peek(crypto_period_index,
|
|
&ref_counted_encryption_key_map,
|
|
kGetKeyTimeoutInSeconds * 1000);
|
|
if (!status.ok()) {
|
|
if (status.error_code() == error::STOPPED) {
|
|
CHECK(!common_encryption_request_status_.ok());
|
|
return common_encryption_request_status_;
|
|
}
|
|
return status;
|
|
}
|
|
|
|
EncryptionKeyMap& encryption_key_map = ref_counted_encryption_key_map->map();
|
|
if (encryption_key_map.find(track_type) == encryption_key_map.end()) {
|
|
return Status(error::INTERNAL_ERROR,
|
|
"Cannot find key of type " + TrackTypeToString(track_type));
|
|
}
|
|
*key = *encryption_key_map[track_type];
|
|
return Status::OK;
|
|
}
|
|
|
|
void WidevineEncryptionKeySource::FetchKeysTask() {
|
|
Status status = FetchKeys(first_crypto_period_index_);
|
|
if (key_rotation_enabled_) {
|
|
while (status.ok()) {
|
|
first_crypto_period_index_ += crypto_period_count_;
|
|
status = FetchKeys(first_crypto_period_index_);
|
|
}
|
|
}
|
|
common_encryption_request_status_ = status;
|
|
key_pool_.Stop();
|
|
}
|
|
|
|
Status WidevineEncryptionKeySource::FetchKeys(
|
|
uint32 first_crypto_period_index) {
|
|
std::string request;
|
|
FillRequest(content_id_, first_crypto_period_index, &request);
|
|
|
|
std::string message;
|
|
Status status = SignRequest(request, &message);
|
|
if (!status.ok())
|
|
return status;
|
|
VLOG(1) << "Message: " << message;
|
|
|
|
std::string raw_response;
|
|
int64 sleep_duration = kFirstRetryDelayMilliseconds;
|
|
|
|
// Perform client side retries if seeing server transient error to workaround
|
|
// server limitation.
|
|
for (int i = 0; i < kNumTransientErrorRetries; ++i) {
|
|
status = http_fetcher_->Post(server_url_, message, &raw_response);
|
|
if (!status.ok())
|
|
return status;
|
|
VLOG(1) << "Retry [" << i << "] Response:" << raw_response;
|
|
|
|
std::string response;
|
|
if (!DecodeResponse(raw_response, &response)) {
|
|
return Status(error::SERVER_ERROR,
|
|
"Failed to decode response '" + raw_response + "'.");
|
|
}
|
|
|
|
bool transient_error = false;
|
|
if (ExtractEncryptionKey(response, &transient_error))
|
|
return Status::OK;
|
|
|
|
if (!transient_error) {
|
|
return Status(
|
|
error::SERVER_ERROR,
|
|
"Failed to extract encryption key from '" + response + "'.");
|
|
}
|
|
|
|
// Exponential backoff.
|
|
if (i != kNumTransientErrorRetries - 1) {
|
|
base::PlatformThread::Sleep(
|
|
base::TimeDelta::FromMilliseconds(sleep_duration));
|
|
sleep_duration *= 2;
|
|
}
|
|
}
|
|
return Status(error::SERVER_ERROR,
|
|
"Failed to recover from server internal error.");
|
|
}
|
|
|
|
void WidevineEncryptionKeySource::FillRequest(const std::string& content_id,
|
|
uint32 first_crypto_period_index,
|
|
std::string* request) {
|
|
DCHECK(request);
|
|
|
|
std::string content_id_base64_string;
|
|
base::Base64Encode(content_id, &content_id_base64_string);
|
|
|
|
base::DictionaryValue request_dict;
|
|
request_dict.SetString("content_id", content_id_base64_string);
|
|
request_dict.SetString("policy", "");
|
|
|
|
// Build tracks.
|
|
base::ListValue* tracks = new base::ListValue();
|
|
|
|
base::DictionaryValue* track_sd = new base::DictionaryValue();
|
|
track_sd->SetString("type", "SD");
|
|
tracks->Append(track_sd);
|
|
base::DictionaryValue* track_hd = new base::DictionaryValue();
|
|
track_hd->SetString("type", "HD");
|
|
tracks->Append(track_hd);
|
|
base::DictionaryValue* track_audio = new base::DictionaryValue();
|
|
track_audio->SetString("type", "AUDIO");
|
|
tracks->Append(track_audio);
|
|
|
|
request_dict.Set("tracks", tracks);
|
|
|
|
// Build DRM types.
|
|
base::ListValue* drm_types = new base::ListValue();
|
|
drm_types->AppendString("WIDEVINE");
|
|
request_dict.Set("drm_types", drm_types);
|
|
|
|
// Build key rotation fields.
|
|
if (key_rotation_enabled_) {
|
|
request_dict.SetInteger("first_crypto_period_index",
|
|
first_crypto_period_index);
|
|
request_dict.SetInteger("crypto_period_count", crypto_period_count_);
|
|
}
|
|
|
|
base::JSONWriter::Write(&request_dict, request);
|
|
}
|
|
|
|
Status WidevineEncryptionKeySource::SignRequest(const std::string& request,
|
|
std::string* signed_request) {
|
|
DCHECK(signed_request);
|
|
|
|
// Sign the request.
|
|
std::string signature;
|
|
if (!signer_->GenerateSignature(request, &signature))
|
|
return Status(error::INTERNAL_ERROR, "Signature generation failed.");
|
|
|
|
// Encode request and signature using Base64 encoding.
|
|
std::string request_base64_string;
|
|
base::Base64Encode(request, &request_base64_string);
|
|
|
|
std::string signature_base64_string;
|
|
base::Base64Encode(signature, &signature_base64_string);
|
|
|
|
base::DictionaryValue signed_request_dict;
|
|
signed_request_dict.SetString("request", request_base64_string);
|
|
signed_request_dict.SetString("signature", signature_base64_string);
|
|
signed_request_dict.SetString("signer", signer_->signer_name());
|
|
|
|
base::JSONWriter::Write(&signed_request_dict, signed_request);
|
|
return Status::OK;
|
|
}
|
|
|
|
bool WidevineEncryptionKeySource::DecodeResponse(
|
|
const std::string& raw_response,
|
|
std::string* response) {
|
|
DCHECK(response);
|
|
|
|
// Extract base64 formatted response from JSON formatted raw response.
|
|
scoped_ptr<base::Value> root(base::JSONReader::Read(raw_response));
|
|
if (!root) {
|
|
LOG(ERROR) << "'" << raw_response << "' is not in JSON format.";
|
|
return false;
|
|
}
|
|
const base::DictionaryValue* response_dict = NULL;
|
|
RCHECK(root->GetAsDictionary(&response_dict));
|
|
|
|
std::string response_base64_string;
|
|
RCHECK(response_dict->GetString("response", &response_base64_string));
|
|
RCHECK(base::Base64Decode(response_base64_string, response));
|
|
return true;
|
|
}
|
|
|
|
bool WidevineEncryptionKeySource::ExtractEncryptionKey(
|
|
const std::string& response,
|
|
bool* transient_error) {
|
|
DCHECK(transient_error);
|
|
*transient_error = false;
|
|
|
|
scoped_ptr<base::Value> root(base::JSONReader::Read(response));
|
|
if (!root) {
|
|
LOG(ERROR) << "'" << response << "' is not in JSON format.";
|
|
return false;
|
|
}
|
|
|
|
const base::DictionaryValue* license_dict = NULL;
|
|
RCHECK(root->GetAsDictionary(&license_dict));
|
|
|
|
std::string license_status;
|
|
RCHECK(license_dict->GetString("status", &license_status));
|
|
if (license_status != kLicenseStatusOK) {
|
|
LOG(ERROR) << "Received non-OK license response: " << response;
|
|
*transient_error = (license_status == kLicenseStatusTransientError);
|
|
return false;
|
|
}
|
|
|
|
const base::ListValue* tracks;
|
|
RCHECK(license_dict->GetList("tracks", &tracks));
|
|
RCHECK(key_rotation_enabled_
|
|
? tracks->GetSize() >= NUM_VALID_TRACK_TYPES * crypto_period_count_
|
|
: tracks->GetSize() >= NUM_VALID_TRACK_TYPES);
|
|
|
|
int current_crypto_period_index = first_crypto_period_index_;
|
|
|
|
EncryptionKeyMap encryption_key_map;
|
|
for (size_t i = 0; i < tracks->GetSize(); ++i) {
|
|
const base::DictionaryValue* track_dict;
|
|
RCHECK(tracks->GetDictionary(i, &track_dict));
|
|
|
|
if (key_rotation_enabled_) {
|
|
int crypto_period_index;
|
|
RCHECK(
|
|
track_dict->GetInteger("crypto_period_index", &crypto_period_index));
|
|
if (crypto_period_index != current_crypto_period_index) {
|
|
if (crypto_period_index != current_crypto_period_index + 1) {
|
|
LOG(ERROR) << "Expecting crypto period index "
|
|
<< current_crypto_period_index << " or "
|
|
<< current_crypto_period_index + 1 << "; Seen "
|
|
<< crypto_period_index << " at track " << i;
|
|
return false;
|
|
}
|
|
if (!PushToKeyPool(&encryption_key_map))
|
|
return false;
|
|
++current_crypto_period_index;
|
|
}
|
|
}
|
|
|
|
std::string track_type_str;
|
|
RCHECK(track_dict->GetString("type", &track_type_str));
|
|
TrackType track_type = GetTrackTypeFromString(track_type_str);
|
|
DCHECK_NE(TRACK_TYPE_UNKNOWN, track_type);
|
|
RCHECK(encryption_key_map.find(track_type) == encryption_key_map.end());
|
|
|
|
scoped_ptr<EncryptionKey> encryption_key(new EncryptionKey());
|
|
std::vector<uint8> pssh_data;
|
|
if (!GetKeyAndKeyId(
|
|
*track_dict, &encryption_key->key, &encryption_key->key_id) ||
|
|
!GetPsshData(*track_dict, &pssh_data))
|
|
return false;
|
|
encryption_key->pssh = PsshBoxFromPsshData(pssh_data);
|
|
encryption_key_map[track_type] = encryption_key.release();
|
|
}
|
|
|
|
DCHECK(!encryption_key_map.empty());
|
|
return PushToKeyPool(&encryption_key_map);
|
|
}
|
|
|
|
bool WidevineEncryptionKeySource::PushToKeyPool(
|
|
EncryptionKeyMap* encryption_key_map) {
|
|
DCHECK(encryption_key_map);
|
|
Status status =
|
|
key_pool_.Push(scoped_refptr<RefCountedEncryptionKeyMap>(
|
|
new RefCountedEncryptionKeyMap(encryption_key_map)),
|
|
kInfiniteTimeout);
|
|
encryption_key_map->clear();
|
|
if (!status.ok()) {
|
|
DCHECK_EQ(error::STOPPED, status.error_code());
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
} // namespace media
|