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Commit f2af00e8 authored by Chong Zhang's avatar Chong Zhang Committed by Ryan Longair
Browse files

Fix race condition for cas sessions 

Change the session to shared_ptr and use atomic_load/store.

Test: POC; CTS MediaCasTest; CTS MediaDrmClearkeyTest#
testClearKeyPlaybackMpeg2ts
bug: 113027383

Change-Id: I75f4cb33a022f28d45918442d64c5c46df2640ef
(cherry picked from commit 7934a8f7)
parent b1b11dc8

drm/mediacas/plugins/clearkey/ClearKeyCasPlugin.cpp

+13 −11
Original line number Diff line number Diff line
@@ -118,9 +118,9 @@ status_t ClearKeyCasPlugin::openSession(CasSessionId* sessionId) { 


status_t ClearKeyCasPlugin::closeSession(const CasSessionId &sessionId) {

    ALOGV("closeSession: sessionId=%s", sessionIdToString(sessionId).string());

    sp<ClearKeyCasSession> session =

    std::shared_ptr<ClearKeyCasSession> session =

            ClearKeySessionLibrary::get()->findSession(sessionId);

    if (session == NULL) {

    if (session.get() == nullptr) {

        return ERROR_CAS_SESSION_NOT_OPENED;

    }
@@ -132,9 +132,9 @@ status_t ClearKeyCasPlugin::setSessionPrivateData( 
        const CasSessionId &sessionId, const CasData & /*data*/) {

    ALOGV("setSessionPrivateData: sessionId=%s",

            sessionIdToString(sessionId).string());

    sp<ClearKeyCasSession> session =

    std::shared_ptr<ClearKeyCasSession> session =

            ClearKeySessionLibrary::get()->findSession(sessionId);

    if (session == NULL) {

    if (session.get() == nullptr) {

        return ERROR_CAS_SESSION_NOT_OPENED;

    }

    return OK;
@@ -143,9 +143,9 @@ status_t ClearKeyCasPlugin::setSessionPrivateData( 
status_t ClearKeyCasPlugin::processEcm(

        const CasSessionId &sessionId, const CasEcm& ecm) {

    ALOGV("processEcm: sessionId=%s", sessionIdToString(sessionId).string());

    sp<ClearKeyCasSession> session =

    std::shared_ptr<ClearKeyCasSession> session =

            ClearKeySessionLibrary::get()->findSession(sessionId);

    if (session == NULL) {

    if (session.get() == nullptr) {

        return ERROR_CAS_SESSION_NOT_OPENED;

    }
@@ -418,15 +418,15 @@ status_t ClearKeyDescramblerPlugin::setMediaCasSession( 
        const CasSessionId &sessionId) {

    ALOGV("setMediaCasSession: sessionId=%s", sessionIdToString(sessionId).string());



    sp<ClearKeyCasSession> session =

    std::shared_ptr<ClearKeyCasSession> session =

            ClearKeySessionLibrary::get()->findSession(sessionId);



    if (session == NULL) {

    if (session.get() == nullptr) {

        ALOGE("ClearKeyDescramblerPlugin: session not found");

        return ERROR_CAS_SESSION_NOT_OPENED;

    }



    mCASSession = session;

    std::atomic_store(&mCASSession, session);

    return OK;

}
@@ -447,12 +447,14 @@ ssize_t ClearKeyDescramblerPlugin::descramble( 
          subSamplesToString(subSamples, numSubSamples).string(),

          srcPtr, dstPtr, srcOffset, dstOffset);



    if (mCASSession == NULL) {

    std::shared_ptr<ClearKeyCasSession> session = std::atomic_load(&mCASSession);



    if (session.get() == nullptr) {

        ALOGE("Uninitialized CAS session!");

        return ERROR_CAS_DECRYPT_UNIT_NOT_INITIALIZED;

    }



    return mCASSession->decrypt(

    return session->decrypt(

            secure, scramblingControl,

            numSubSamples, subSamples,

            (uint8_t*)srcPtr + srcOffset,

drm/mediacas/plugins/clearkey/ClearKeyCasPlugin.h

+1 −1
Original line number Diff line number Diff line
@@ -120,7 +120,7 @@ public: 
            AString *errorDetailMsg) override;



private:

    sp<ClearKeyCasSession> mCASSession;

    std::shared_ptr<ClearKeyCasSession> mCASSession;



    String8 subSamplesToString(

            SubSample const *subSamples,

drm/mediacas/plugins/clearkey/ClearKeySessionLibrary.cpp

+4 −4
Original line number Diff line number Diff line
@@ -56,7 +56,7 @@ status_t ClearKeySessionLibrary::addSession( 


    Mutex::Autolock lock(mSessionsLock);



    sp<ClearKeyCasSession> session = new ClearKeyCasSession(plugin);

    std::shared_ptr<ClearKeyCasSession> session(new ClearKeyCasSession(plugin));



    uint8_t *byteArray = (uint8_t *) &mNextSessionId;

    sessionId->push_back(byteArray[3]);
@@ -69,7 +69,7 @@ status_t ClearKeySessionLibrary::addSession( 
    return OK;

}



sp<ClearKeyCasSession> ClearKeySessionLibrary::findSession(

std::shared_ptr<ClearKeyCasSession> ClearKeySessionLibrary::findSession(

        const CasSessionId& sessionId) {

    Mutex::Autolock lock(mSessionsLock);
@@ -88,7 +88,7 @@ void ClearKeySessionLibrary::destroySession(const CasSessionId& sessionId) { 
        return;

    }



    sp<ClearKeyCasSession> session = mIDToSessionMap.valueAt(index);

    std::shared_ptr<ClearKeyCasSession> session = mIDToSessionMap.valueAt(index);

    mIDToSessionMap.removeItemsAt(index);

}
@@ -96,7 +96,7 @@ void ClearKeySessionLibrary::destroyPlugin(CasPlugin *plugin) { 
    Mutex::Autolock lock(mSessionsLock);



    for (ssize_t index = (ssize_t)mIDToSessionMap.size() - 1; index >= 0; index--) {

        sp<ClearKeyCasSession> session = mIDToSessionMap.valueAt(index);

        std::shared_ptr<ClearKeyCasSession> session = mIDToSessionMap.valueAt(index);

        if (session->getPlugin() == plugin) {

            mIDToSessionMap.removeItemsAt(index);

        }

drm/mediacas/plugins/clearkey/ClearKeySessionLibrary.h

+6 −4
Original line number Diff line number Diff line
@@ -32,6 +32,10 @@ class KeyFetcher; 


class ClearKeyCasSession : public RefBase {

public:

    explicit ClearKeyCasSession(CasPlugin *plugin);



    virtual ~ClearKeyCasSession();



    ssize_t decrypt(

            bool secure,

            DescramblerPlugin::ScramblingControl scramblingControl,
@@ -58,8 +62,6 @@ private: 


    friend class ClearKeySessionLibrary;



    explicit ClearKeyCasSession(CasPlugin *plugin);

    virtual ~ClearKeyCasSession();

    CasPlugin* getPlugin() const { return mPlugin; }

    status_t decryptPayload(

            const AES_KEY& key, size_t length, size_t offset, char* buffer) const;
@@ -73,7 +75,7 @@ public: 


    status_t addSession(CasPlugin *plugin, CasSessionId *sessionId);



    sp<ClearKeyCasSession> findSession(const CasSessionId& sessionId);

    std::shared_ptr<ClearKeyCasSession> findSession(const CasSessionId& sessionId);



    void destroySession(const CasSessionId& sessionId);
@@ -85,7 +87,7 @@ private: 


    Mutex mSessionsLock;

    uint32_t mNextSessionId;

    KeyedVector<CasSessionId, sp<ClearKeyCasSession>> mIDToSessionMap;

    KeyedVector<CasSessionId, std::shared_ptr<ClearKeyCasSession>> mIDToSessionMap;



    ClearKeySessionLibrary();

    DISALLOW_EVIL_CONSTRUCTORS(ClearKeySessionLibrary);