tor-browser

ClearKeySessionManager.cpp (24743B)

---

/*
* Copyright 2015, Mozilla Foundation and contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

#include "ClearKeySessionManager.h"

#include <assert.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#include "ClearKeyDecryptionManager.h"
#include "ClearKeyPersistence.h"
#include "ClearKeyStorage.h"
#include "ClearKeyUtils.h"
#include "content_decryption_module.h"
#include "psshparser/PsshParser.h"

using namespace cdm;

using std::function;
using std::string;
using std::vector;

ClearKeySessionManager::ClearKeySessionManager(Host_11* aHost)
   : mDecryptionManager(ClearKeyDecryptionManager::Get()) {
 CK_LOGD("ClearKeySessionManager ctor %p", this);
 AddRef();

 mHost = aHost;
 mPersistence = new ClearKeyPersistence(mHost);
}

ClearKeySessionManager::~ClearKeySessionManager() {
 CK_LOGD("ClearKeySessionManager dtor %p", this);
}

void ClearKeySessionManager::Init(bool aDistinctiveIdentifierAllowed,
                                 bool aPersistentStateAllowed) {
 CK_LOGD("ClearKeySessionManager::Init");

 RefPtr<ClearKeySessionManager> self(this);
 function<void()> onPersistentStateLoaded = [self]() {
   while (!self->mDeferredInitialize.empty()) {
     function<void()> func = self->mDeferredInitialize.front();
     self->mDeferredInitialize.pop();

     func();
   }
   if (self->mHost) {
     // The session manager should be the last thing the ClearKey CDM is
     // waiting on to be initialized.
     self->mHost->OnInitialized(true);
   }
 };

 mPersistence->EnsureInitialized(aPersistentStateAllowed,
                                 std::move(onPersistentStateLoaded));
}

void ClearKeySessionManager::CreateSession(uint32_t aPromiseId,
                                          InitDataType aInitDataType,
                                          const uint8_t* aInitData,
                                          uint32_t aInitDataSize,
                                          SessionType aSessionType) {
 CK_LOGD("ClearKeySessionManager::CreateSession type:%u", aInitDataType);

 // Copy the init data so it is correctly captured by the lambda
 vector<uint8_t> initData(aInitData, aInitData + aInitDataSize);

 RefPtr<ClearKeySessionManager> self(this);
 function<void()> deferrer = [self, aPromiseId, aInitDataType, initData,
                              aSessionType]() {
   self->CreateSession(aPromiseId, aInitDataType, initData.data(),
                       initData.size(), aSessionType);
 };

 // If we haven't loaded, don't do this yet
 if (MaybeDeferTillInitialized(std::move(deferrer))) {
   CK_LOGD("Deferring CreateSession");
   return;
 }

 CK_LOGARRAY("ClearKeySessionManager::CreateSession initdata: ", aInitData,
             aInitDataSize);

 // If 'DecryptingComplete' has been called mHost will be null so we can't
 // won't be able to resolve our promise
 if (!mHost) {
   CK_LOGD("ClearKeySessionManager::CreateSession: mHost is nullptr");
   return;
 }

 // initDataType must be "cenc", "keyids", or "webm".
 if (aInitDataType != InitDataType::kCenc &&
     aInitDataType != InitDataType::kKeyIds &&
     aInitDataType != InitDataType::kWebM) {
   string message = "initDataType is not supported by ClearKey";
   mHost->OnRejectPromise(aPromiseId, Exception::kExceptionNotSupportedError,
                          0, message.c_str(), message.size());

   return;
 }

 string sessionId = mPersistence->GetNewSessionId(aSessionType);
 assert(mSessions.find(sessionId) == mSessions.end());

 ClearKeySession* session = new ClearKeySession(sessionId, aSessionType);

 if (!session->Init(aInitDataType, aInitData, aInitDataSize)) {
   CK_LOGD("Failed to initialize session: %s", sessionId.c_str());

   const static char* message = "Failed to initialize session";
   mHost->OnRejectPromise(aPromiseId, Exception::kExceptionInvalidStateError,
                          0, message, strlen(message));
   delete session;

   return;
 }

 mSessions[sessionId] = session;
 mLastSessionId = sessionId;

 const vector<KeyId>& sessionKeys = session->GetKeyIds();
 vector<KeyId> neededKeys;

 for (auto it = sessionKeys.begin(); it != sessionKeys.end(); it++) {
   // Need to request this key ID from the client. We always send a key
   // request, whether or not another session has sent a request with the same
   // key ID. Otherwise a script can end up waiting for another script to
   // respond to the request (which may not necessarily happen).
   CK_LOGARRAY("Key ID: ", it->data(), it->size());
   neededKeys.push_back(*it);
   mDecryptionManager->ExpectKeyId(*it);
 }

 if (neededKeys.empty()) {
   CK_LOGD("No keys needed from client.");
   return;
 }

 // Send a request for needed key data.
 string request;
 ClearKeyUtils::MakeKeyRequest(neededKeys, request, aSessionType);

 // Resolve the promise with the new session information.
 mHost->OnResolveNewSessionPromise(aPromiseId, sessionId.c_str(),
                                   sessionId.size());

 mHost->OnSessionMessage(sessionId.c_str(), sessionId.size(),
                         MessageType::kLicenseRequest, request.c_str(),
                         request.size());
}

void ClearKeySessionManager::LoadSession(uint32_t aPromiseId,
                                        const char* aSessionId,
                                        uint32_t aSessionIdLength) {
 CK_LOGD("ClearKeySessionManager::LoadSession");

 // Copy the sessionId into a string so the lambda captures it properly.
 string sessionId(aSessionId, aSessionId + aSessionIdLength);

 // Hold a reference to the SessionManager so that it isn't released before
 // we try to use it.
 RefPtr<ClearKeySessionManager> self(this);
 function<void()> deferrer = [self, aPromiseId, sessionId]() {
   self->LoadSession(aPromiseId, sessionId.data(), sessionId.size());
 };

 if (MaybeDeferTillInitialized(std::move(deferrer))) {
   CK_LOGD("Deferring LoadSession");
   return;
 }

 // If the SessionManager has been shutdown mHost will be null and we won't
 // be able to resolve the promise.
 if (!mHost) {
   return;
 }

 if (!ClearKeyUtils::IsValidSessionId(aSessionId, aSessionIdLength)) {
   mHost->OnResolveNewSessionPromise(aPromiseId, nullptr, 0);
   return;
 }

 if (!mPersistence->IsPersistentSessionId(sessionId)) {
   mHost->OnResolveNewSessionPromise(aPromiseId, nullptr, 0);
   return;
 }

 function<void(const uint8_t*, uint32_t)> success =
     [self, sessionId, aPromiseId](const uint8_t* data, uint32_t size) {
       self->PersistentSessionDataLoaded(aPromiseId, sessionId, data, size);
     };

 function<void()> failure = [self, aPromiseId] {
   if (!self->mHost) {
     return;
   }
   // As per the API described in ContentDecryptionModule_8
   self->mHost->OnResolveNewSessionPromise(aPromiseId, nullptr, 0);
 };

 ReadData(mHost, sessionId, std::move(success), std::move(failure));
}

void ClearKeySessionManager::PersistentSessionDataLoaded(
   uint32_t aPromiseId, const string& aSessionId, const uint8_t* aKeyData,
   uint32_t aKeyDataSize) {
 CK_LOGD("ClearKeySessionManager::PersistentSessionDataLoaded");

 // Check that the SessionManager has not been shut down before we try and
 // resolve any promises.
 if (!mHost) {
   return;
 }

 if (Contains(mSessions, aSessionId) ||
     (aKeyDataSize % (2 * CENC_KEY_LEN)) != 0) {
   // As per the instructions in ContentDecryptionModule_8
   mHost->OnResolveNewSessionPromise(aPromiseId, nullptr, 0);
   return;
 }

 ClearKeySession* session =
     new ClearKeySession(aSessionId, SessionType::kPersistentLicense);

 mSessions[aSessionId] = session;
 mLastSessionId = aSessionId;

 uint32_t numKeys = aKeyDataSize / (2 * CENC_KEY_LEN);

 vector<KeyInformation> keyInfos;
 vector<KeyIdPair> keyPairs;
 for (uint32_t i = 0; i < numKeys; i++) {
   const uint8_t* base = aKeyData + 2 * CENC_KEY_LEN * i;

   KeyIdPair keyPair;

   keyPair.mKeyId = KeyId(base, base + CENC_KEY_LEN);
   assert(keyPair.mKeyId.size() == CENC_KEY_LEN);

   keyPair.mKey = Key(base + CENC_KEY_LEN, base + 2 * CENC_KEY_LEN);
   assert(keyPair.mKey.size() == CENC_KEY_LEN);

   session->AddKeyId(keyPair.mKeyId);

   mDecryptionManager->ExpectKeyId(keyPair.mKeyId);
   mDecryptionManager->InitKey(keyPair.mKeyId, keyPair.mKey);
   mKeyIds.insert(keyPair.mKey);
   keyPairs.push_back(keyPair);

   KeyInformation keyInfo = {};
   keyInfo.key_id = keyPairs.back().mKeyId.data();
   keyInfo.key_id_size = keyPair.mKeyId.size();
   keyInfo.status = KeyStatus::kUsable;

   keyInfos.push_back(keyInfo);
 }

 mHost->OnSessionKeysChange(aSessionId.data(), aSessionId.size(), true,
                            keyInfos.data(), keyInfos.size());

 mHost->OnResolveNewSessionPromise(aPromiseId, aSessionId.c_str(),
                                   aSessionId.size());
}

void ClearKeySessionManager::UpdateSession(uint32_t aPromiseId,
                                          const char* aSessionId,
                                          uint32_t aSessionIdLength,
                                          const uint8_t* aResponse,
                                          uint32_t aResponseSize) {
 CK_LOGD("ClearKeySessionManager::UpdateSession");

 // Copy the method arguments so we can capture them in the lambda
 string sessionId(aSessionId, aSessionId + aSessionIdLength);
 vector<uint8_t> response(aResponse, aResponse + aResponseSize);

 // Hold  a reference to the SessionManager so it isn't released before we
 // callback.
 RefPtr<ClearKeySessionManager> self(this);
 function<void()> deferrer = [self, aPromiseId, sessionId, response]() {
   self->UpdateSession(aPromiseId, sessionId.data(), sessionId.size(),
                       response.data(), response.size());
 };

 // If we haven't fully loaded, defer calling this method
 if (MaybeDeferTillInitialized(std::move(deferrer))) {
   CK_LOGD("Deferring LoadSession");
   return;
 }

 // Make sure the SessionManager has not been shutdown before we try and
 // resolve any promises.
 if (!mHost) {
   return;
 }

 CK_LOGD("Updating session: %s", sessionId.c_str());

 auto itr = mSessions.find(sessionId);
 if (itr == mSessions.end() || !(itr->second)) {
   CK_LOGW("ClearKey CDM couldn't resolve session ID in UpdateSession.");
   CK_LOGD("Unable to find session: %s", sessionId.c_str());
   mHost->OnRejectPromise(aPromiseId, Exception::kExceptionTypeError, 0,
                          nullptr, 0);

   return;
 }
 ClearKeySession* session = itr->second;

 // Verify the size of session response.
 if (aResponseSize >= kMaxSessionResponseLength) {
   CK_LOGW("Session response size is not within a reasonable size.");
   CK_LOGD("Failed to parse response for session %s", sessionId.c_str());

   mHost->OnRejectPromise(aPromiseId, Exception::kExceptionTypeError, 0,
                          nullptr, 0);

   return;
 }

 // Parse the response for any (key ID, key) pairs.
 vector<KeyIdPair> keyPairs;
 if (!ClearKeyUtils::ParseJWK(aResponse, aResponseSize, keyPairs,
                              session->Type())) {
   CK_LOGW("ClearKey CDM failed to parse JSON Web Key.");

   mHost->OnRejectPromise(aPromiseId, Exception::kExceptionTypeError, 0,
                          nullptr, 0);

   return;
 }

 vector<KeyInformation> keyInfos;
 for (size_t i = 0; i < keyPairs.size(); i++) {
   KeyIdPair& keyPair = keyPairs[i];
   mDecryptionManager->InitKey(keyPair.mKeyId, keyPair.mKey);
   mKeyIds.insert(keyPair.mKeyId);

   KeyInformation keyInfo = {};
   keyInfo.key_id = keyPair.mKeyId.data();
   keyInfo.key_id_size = keyPair.mKeyId.size();
   keyInfo.status = KeyStatus::kUsable;

   keyInfos.push_back(keyInfo);
 }

 mHost->OnSessionKeysChange(aSessionId, aSessionIdLength, true,
                            keyInfos.data(), keyInfos.size());

 if (session->Type() != SessionType::kPersistentLicense) {
   mHost->OnResolvePromise(aPromiseId);
   return;
 }

 // Store the keys on disk. We store a record whose name is the sessionId,
 // and simply append each keyId followed by its key.
 vector<uint8_t> keydata;
 Serialize(session, keydata);

 function<void()> resolve = [self, aPromiseId]() {
   if (!self->mHost) {
     return;
   }
   self->mHost->OnResolvePromise(aPromiseId);
 };

 function<void()> reject = [self, aPromiseId]() {
   if (!self->mHost) {
     return;
   }

   static const char* message = "Couldn't store cenc key init data";
   self->mHost->OnRejectPromise(aPromiseId,
                                Exception::kExceptionInvalidStateError, 0,
                                message, strlen(message));
 };

 WriteData(mHost, sessionId, keydata, std::move(resolve), std::move(reject));
}

void ClearKeySessionManager::Serialize(const ClearKeySession* aSession,
                                      std::vector<uint8_t>& aOutKeyData) {
 const std::vector<KeyId>& keyIds = aSession->GetKeyIds();
 for (size_t i = 0; i < keyIds.size(); i++) {
   const KeyId& keyId = keyIds[i];
   if (!mDecryptionManager->HasKeyForKeyId(keyId)) {
     continue;
   }
   assert(keyId.size() == CENC_KEY_LEN);
   aOutKeyData.insert(aOutKeyData.end(), keyId.begin(), keyId.end());
   const Key& key = mDecryptionManager->GetDecryptionKey(keyId);
   assert(key.size() == CENC_KEY_LEN);
   aOutKeyData.insert(aOutKeyData.end(), key.begin(), key.end());
 }
}

void ClearKeySessionManager::CloseSession(uint32_t aPromiseId,
                                         const char* aSessionId,
                                         uint32_t aSessionIdLength) {
 CK_LOGD("ClearKeySessionManager::CloseSession");

 // Copy the sessionId into a string so we capture it properly.
 string sessionId(aSessionId, aSessionId + aSessionIdLength);
 // Hold a reference to the session manager, so it doesn't get deleted
 // before we need to use it.
 RefPtr<ClearKeySessionManager> self(this);
 function<void()> deferrer = [self, aPromiseId, sessionId]() {
   self->CloseSession(aPromiseId, sessionId.data(), sessionId.size());
 };

 // If we haven't loaded, call this method later.
 if (MaybeDeferTillInitialized(std::move(deferrer))) {
   CK_LOGD("Deferring CloseSession");
   return;
 }

 // If DecryptingComplete has been called mHost will be null and we won't
 // be able to resolve our promise.
 if (!mHost) {
   return;
 }

 auto itr = mSessions.find(sessionId);
 if (itr == mSessions.end()) {
   CK_LOGW("ClearKey CDM couldn't close non-existent session.");
   mHost->OnRejectPromise(aPromiseId, Exception::kExceptionTypeError, 0,
                          nullptr, 0);

   return;
 }

 ClearKeySession* session = itr->second;
 assert(session);

 ClearInMemorySessionData(session);

 mHost->OnSessionClosed(aSessionId, aSessionIdLength);
 mHost->OnResolvePromise(aPromiseId);
}

void ClearKeySessionManager::ClearInMemorySessionData(
   ClearKeySession* aSession) {
 mSessions.erase(aSession->Id());
 delete aSession;
}

void ClearKeySessionManager::RemoveSession(uint32_t aPromiseId,
                                          const char* aSessionId,
                                          uint32_t aSessionIdLength) {
 CK_LOGD("ClearKeySessionManager::RemoveSession");

 // Copy the sessionId into a string so it can be captured for the lambda.
 string sessionId(aSessionId, aSessionId + aSessionIdLength);

 // Hold a reference to the SessionManager, so it isn't released before we
 // try and use it.
 RefPtr<ClearKeySessionManager> self(this);
 function<void()> deferrer = [self, aPromiseId, sessionId]() {
   self->RemoveSession(aPromiseId, sessionId.data(), sessionId.size());
 };

 // If we haven't fully loaded, defer calling this method.
 if (MaybeDeferTillInitialized(std::move(deferrer))) {
   CK_LOGD("Deferring RemoveSession");
   return;
 }

 // Check that the SessionManager has not been shutdown before we try and
 // resolve any promises.
 if (!mHost) {
   return;
 }

 auto itr = mSessions.find(sessionId);
 if (itr == mSessions.end()) {
   CK_LOGW("ClearKey CDM couldn't remove non-existent session.");

   mHost->OnRejectPromise(aPromiseId, Exception::kExceptionTypeError, 0,
                          nullptr, 0);

   return;
 }

 ClearKeySession* session = itr->second;
 assert(session);
 string sid = session->Id();
 bool isPersistent = session->Type() == SessionType::kPersistentLicense;
 ClearInMemorySessionData(session);

 if (!isPersistent) {
   mHost->OnResolvePromise(aPromiseId);
   return;
 }

 mPersistence->PersistentSessionRemoved(sid);

 vector<uint8_t> emptyKeydata;

 function<void()> resolve = [self, aPromiseId]() {
   if (!self->mHost) {
     return;
   }
   self->mHost->OnResolvePromise(aPromiseId);
 };

 function<void()> reject = [self, aPromiseId]() {
   if (!self->mHost) {
     return;
   }
   static const char* message = "Could not remove session";
   self->mHost->OnRejectPromise(aPromiseId, Exception::kExceptionTypeError, 0,
                                message, strlen(message));
 };

 WriteData(mHost, sessionId, emptyKeydata, std::move(resolve),
           std::move(reject));
}

void ClearKeySessionManager::SetServerCertificate(uint32_t aPromiseId,
                                                 const uint8_t* aServerCert,
                                                 uint32_t aServerCertSize) {
 // ClearKey CDM doesn't support this method by spec.
 CK_LOGD("ClearKeySessionManager::SetServerCertificate");
 mHost->OnRejectPromise(aPromiseId, Exception::kExceptionNotSupportedError, 0,
                        nullptr /* message */, 0 /* messageLen */);
}

Status ClearKeySessionManager::Decrypt(const InputBuffer_2& aBuffer,
                                      DecryptedBlock* aDecryptedBlock) {
 CK_LOGD("ClearKeySessionManager::Decrypt");

 CK_LOGARRAY("Key: ", aBuffer.key_id, aBuffer.key_id_size);

 Buffer* buffer = mHost->Allocate(aBuffer.data_size);
 assert(buffer != nullptr);
 assert(buffer->Data() != nullptr);
 assert(buffer->Capacity() >= aBuffer.data_size);

 memcpy(buffer->Data(), aBuffer.data, aBuffer.data_size);

 Status status = Status::kSuccess;
 // According to the comment `If |iv_size| = 0, the data is unencrypted.`
 // Use iv_size to determine if the sample is encrypted.
 if (aBuffer.iv_size != 0) {
   status = mDecryptionManager->Decrypt(buffer->Data(), buffer->Size(),
                                        CryptoMetaData(&aBuffer));
 }

 aDecryptedBlock->SetDecryptedBuffer(buffer);
 aDecryptedBlock->SetTimestamp(aBuffer.timestamp);

 return status;
}

void ClearKeySessionManager::DecryptingComplete() {
 CK_LOGD("ClearKeySessionManager::DecryptingComplete %p", this);

 for (auto it = mSessions.begin(); it != mSessions.end(); it++) {
   delete it->second;
 }
 mSessions.clear();
 mLastSessionId = std::nullopt;

 mDecryptionManager = nullptr;
 mHost = nullptr;

 Release();
}

bool ClearKeySessionManager::MaybeDeferTillInitialized(
   function<void()>&& aMaybeDefer) {
 if (mPersistence->IsLoaded()) {
   return false;
 }

 mDeferredInitialize.emplace(std::move(aMaybeDefer));
 return true;
}

void ClearKeySessionManager::OnQueryOutputProtectionStatus(
   QueryResult aResult, uint32_t aLinkMask, uint32_t aOutputProtectionMask) {
 MOZ_ASSERT(mHasOutstandingOutputProtectionQuery,
            "Should only be called if a query is outstanding");
 CK_LOGD("ClearKeySessionManager::OnQueryOutputProtectionStatus");
 mHasOutstandingOutputProtectionQuery = false;

 if (aResult == QueryResult::kQueryFailed) {
   // Indicate the query failed. This can happen if we're in shutdown.
   NotifyOutputProtectionStatus(KeyStatus::kInternalError);
   return;
 }

 if (aLinkMask & OutputLinkTypes::kLinkTypeNetwork) {
   NotifyOutputProtectionStatus(KeyStatus::kOutputRestricted);
   return;
 }

 NotifyOutputProtectionStatus(KeyStatus::kUsable);
}

void ClearKeySessionManager::QueryOutputProtectionStatusIfNeeded() {
 MOZ_ASSERT(
     mHost,
     "Should not query protection status if we're shutdown (mHost == null)!");
 CK_LOGD(
     "ClearKeySessionManager::UpdateOutputProtectionStatusAndQueryIfNeeded");
 if (mLastOutputProtectionQueryTime.IsNull()) {
   // We haven't perfomed a check yet, get a query going.
   MOZ_ASSERT(
       !mHasOutstandingOutputProtectionQuery,
       "Shouldn't have an outstanding query if we haven't recorded a time");
   QueryOutputProtectionStatusFromHost();
   return;
 }

 MOZ_ASSERT(!mLastOutputProtectionQueryTime.IsNull(),
            "Should have already handled the case where we don't yet have a "
            "previous check time");
 const mozilla::TimeStamp now = mozilla::TimeStamp::NowLoRes();
 const mozilla::TimeDuration timeSinceQuery =
     now - mLastOutputProtectionQueryTime;

 // The time between output protection checks to the host. I.e. if this amount
 // of time has passed since the last check with the host, another should be
 // performed (provided the first check has been handled).
 static const mozilla::TimeDuration kOutputProtectionQueryInterval =
     mozilla::TimeDuration::FromSeconds(0.2);
 // The number of kOutputProtectionQueryInterval intervals we can miss before
 // we decide a check has failed. I.e. if this value is 2, if we have not
 // received a reply to a check after kOutputProtectionQueryInterval * 2
 // time, we consider the check failed.
 constexpr uint32_t kMissedIntervalsBeforeFailure = 2;
 // The length of time after which we will restrict output until we get a
 // query response.
 static const mozilla::TimeDuration kTimeToWaitBeforeFailure =
     kOutputProtectionQueryInterval * kMissedIntervalsBeforeFailure;

 if ((timeSinceQuery > kOutputProtectionQueryInterval) &&
     !mHasOutstandingOutputProtectionQuery) {
   // We don't have an outstanding query and enough time has passed we should
   // query again.
   QueryOutputProtectionStatusFromHost();
   return;
 }

 if ((timeSinceQuery > kTimeToWaitBeforeFailure) &&
     mHasOutstandingOutputProtectionQuery) {
   // A reponse was not received fast enough, notify.
   NotifyOutputProtectionStatus(KeyStatus::kInternalError);
 }
}

void ClearKeySessionManager::QueryOutputProtectionStatusFromHost() {
 MOZ_ASSERT(
     mHost,
     "Should not query protection status if we're shutdown (mHost == null)!");
 CK_LOGD("ClearKeySessionManager::QueryOutputProtectionStatusFromHost");
 if (mHost) {
   mLastOutputProtectionQueryTime = mozilla::TimeStamp::NowLoRes();
   mHost->QueryOutputProtectionStatus();
   mHasOutstandingOutputProtectionQuery = true;
 }
}

void ClearKeySessionManager::NotifyOutputProtectionStatus(KeyStatus aStatus) {
 MOZ_ASSERT(aStatus == KeyStatus::kUsable ||
                aStatus == KeyStatus::kOutputRestricted ||
                aStatus == KeyStatus::kInternalError,
            "aStatus should have an expected value");
 CK_LOGD("ClearKeySessionManager::NotifyOutputProtectionStatus");
 if (!mLastSessionId.has_value()) {
   // If we don't have a session id, either because we're too early, or are
   // shutting down, don't notify.
   return;
 }

 string& lastSessionId = mLastSessionId.value();

 // Use 'output-protection' as the key ID. This helps tests disambiguate key
 // status updates related to this.
 const uint8_t kKeyId[] = {'o', 'u', 't', 'p', 'u', 't', '-', 'p', 'r',
                           'o', 't', 'e', 'c', 't', 'i', 'o', 'n'};
 KeyInformation keyInfo = {};
 keyInfo.key_id = kKeyId;
 keyInfo.key_id_size = std::size(kKeyId);
 keyInfo.status = aStatus;

 vector<KeyInformation> keyInfos;
 keyInfos.push_back(keyInfo);

 // At time of writing, Gecko's higher level handling doesn't use this arg.
 // However, we set it to false to mimic Chromium's similar case. Since
 // Clearkey is used to test the Chromium CDM path, it doesn't hurt to try
 // and mimic their behaviour.
 bool hasAdditionalUseableKey = false;
 mHost->OnSessionKeysChange(lastSessionId.c_str(), lastSessionId.size(),
                            hasAdditionalUseableKey, keyInfos.data(),
                            keyInfos.size());
}