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Commit addcb3aa authored by Chong Zhang's avatar Chong Zhang
Browse files

cas: fix UAF in descrambler -- DO NOT MERGE 

Change the plugin holder in both CasImpl and DescramblerImpl
to shared_ptr, and use atomic store/load for read/write.

bug: 73172817
Test:CTS MediaCasTest, VTS VtsHalCasV1_0Target, poc in bug
Change-Id: I6b040680c28c38cef2fef3042f570dc64e86bb77
parent 8ca409df

cas/1.0/default/CasImpl.cpp

+36 −45
Original line number Diff line number Diff line
@@ -31,19 +31,8 @@ namespace cas { 
namespace V1_0 {

namespace implementation {



struct CasImpl::PluginHolder : public RefBase {

public:

    explicit PluginHolder(CasPlugin *plugin) : mPlugin(plugin) {}

    ~PluginHolder() { if (mPlugin != NULL) delete mPlugin; }

    CasPlugin* get() { return mPlugin; }



private:

    CasPlugin *mPlugin;

    DISALLOW_EVIL_CONSTRUCTORS(PluginHolder);

};



CasImpl::CasImpl(const sp<ICasListener> &listener)

    : mPluginHolder(NULL), mListener(listener) {

    : mListener(listener) {

    ALOGV("CTOR");

}
@@ -69,7 +58,8 @@ void CasImpl::OnEvent( 


void CasImpl::init(const sp<SharedLibrary>& library, CasPlugin *plugin) {

    mLibrary = library;

    mPluginHolder = new PluginHolder(plugin);

    std::shared_ptr<CasPlugin> holder(plugin);

    std::atomic_store(&mPluginHolder, holder);

}



void CasImpl::onEvent(
@@ -88,21 +78,22 @@ void CasImpl::onEvent( 


Return<Status> CasImpl::setPrivateData(const HidlCasData& pvtData) {

    ALOGV("%s", __FUNCTION__);

    sp<PluginHolder> holder = mPluginHolder;

    if (holder == NULL) {

    std::shared_ptr<CasPlugin> holder = std::atomic_load(&mPluginHolder);

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

        return toStatus(INVALID_OPERATION);

    }

    return toStatus(holder->get()->setPrivateData(pvtData));

    return toStatus(holder->setPrivateData(pvtData));

}



Return<void> CasImpl::openSession(openSession_cb _hidl_cb) {

    ALOGV("%s", __FUNCTION__);

    CasSessionId sessionId;



    sp<PluginHolder> holder = mPluginHolder;

    std::shared_ptr<CasPlugin> holder = std::atomic_load(&mPluginHolder);

    status_t err = INVALID_OPERATION;

    if (holder != NULL) {

        err = holder->get()->openSession(&sessionId);

    if (holder.get() != nullptr) {

        err = holder->openSession(&sessionId);

        holder.reset();

    }



    _hidl_cb(toStatus(err), sessionId);
@@ -114,87 +105,87 @@ Return<Status> CasImpl::setSessionPrivateData( 
        const HidlCasSessionId &sessionId, const HidlCasData& pvtData) {

    ALOGV("%s: sessionId=%s", __FUNCTION__,

            sessionIdToString(sessionId).string());

    sp<PluginHolder> holder = mPluginHolder;

    if (holder == NULL) {

    std::shared_ptr<CasPlugin> holder = std::atomic_load(&mPluginHolder);

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

        return toStatus(INVALID_OPERATION);

    }

    return toStatus(

            holder->get()->setSessionPrivateData(

                    sessionId, pvtData));

    return toStatus(holder->setSessionPrivateData(sessionId, pvtData));

}



Return<Status> CasImpl::closeSession(const HidlCasSessionId &sessionId) {

    ALOGV("%s: sessionId=%s", __FUNCTION__,

            sessionIdToString(sessionId).string());

    sp<PluginHolder> holder = mPluginHolder;

    if (holder == NULL) {

    std::shared_ptr<CasPlugin> holder = std::atomic_load(&mPluginHolder);

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

        return toStatus(INVALID_OPERATION);

    }

    return toStatus(holder->get()->closeSession(sessionId));

    return toStatus(holder->closeSession(sessionId));

}



Return<Status> CasImpl::processEcm(

        const HidlCasSessionId &sessionId, const HidlCasData& ecm) {

    ALOGV("%s: sessionId=%s", __FUNCTION__,

            sessionIdToString(sessionId).string());

    sp<PluginHolder> holder = mPluginHolder;

    if (holder == NULL) {

    std::shared_ptr<CasPlugin> holder = std::atomic_load(&mPluginHolder);

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

        return toStatus(INVALID_OPERATION);

    }



    return toStatus(holder->get()->processEcm(sessionId, ecm));

    return toStatus(holder->processEcm(sessionId, ecm));

}



Return<Status> CasImpl::processEmm(const HidlCasData& emm) {

    ALOGV("%s", __FUNCTION__);

    sp<PluginHolder> holder = mPluginHolder;

    if (holder == NULL) {

    std::shared_ptr<CasPlugin> holder = std::atomic_load(&mPluginHolder);

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

        return toStatus(INVALID_OPERATION);

    }



    return toStatus(holder->get()->processEmm(emm));

    return toStatus(holder->processEmm(emm));

}



Return<Status> CasImpl::sendEvent(

        int32_t event, int32_t arg,

        const HidlCasData& eventData) {

    ALOGV("%s", __FUNCTION__);

    sp<PluginHolder> holder = mPluginHolder;

    if (holder == NULL) {

    std::shared_ptr<CasPlugin> holder = std::atomic_load(&mPluginHolder);

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

        return toStatus(INVALID_OPERATION);

    }



    status_t err = holder->get()->sendEvent(event, arg, eventData);

    status_t err = holder->sendEvent(event, arg, eventData);

    return toStatus(err);

}



Return<Status> CasImpl::provision(const hidl_string& provisionString) {

    ALOGV("%s: provisionString=%s", __FUNCTION__, provisionString.c_str());

    sp<PluginHolder> holder = mPluginHolder;

    if (holder == NULL) {

    std::shared_ptr<CasPlugin> holder = std::atomic_load(&mPluginHolder);

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

        return toStatus(INVALID_OPERATION);

    }



    return toStatus(holder->get()->provision(String8(provisionString.c_str())));

    return toStatus(holder->provision(String8(provisionString.c_str())));

}



Return<Status> CasImpl::refreshEntitlements(

        int32_t refreshType,

        const HidlCasData& refreshData) {

    ALOGV("%s", __FUNCTION__);

    sp<PluginHolder> holder = mPluginHolder;

    if (holder == NULL) {

    std::shared_ptr<CasPlugin> holder = std::atomic_load(&mPluginHolder);

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

        return toStatus(INVALID_OPERATION);

    }



    status_t err = holder->get()->refreshEntitlements(refreshType, refreshData);

    status_t err = holder->refreshEntitlements(refreshType, refreshData);

    return toStatus(err);

}



Return<Status> CasImpl::release() {

    ALOGV("%s: plugin=%p", __FUNCTION__,

            mPluginHolder != NULL ? mPluginHolder->get() : NULL);

    mPluginHolder.clear();

    ALOGV("%s: plugin=%p", __FUNCTION__, mPluginHolder.get());



    std::shared_ptr<CasPlugin> holder(nullptr);

    std::atomic_store(&mPluginHolder, holder);



    return Status::OK;

}

cas/1.0/default/CasImpl.h

+1 −1
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ public: 
private:

    struct PluginHolder;

    sp<SharedLibrary> mLibrary;

    sp<PluginHolder> mPluginHolder;

    std::shared_ptr<CasPlugin> mPluginHolder;

    sp<ICasListener> mListener;



    DISALLOW_EVIL_CONSTRUCTORS(CasImpl);

cas/1.0/default/DescramblerImpl.cpp

+35 −11
Original line number Diff line number Diff line
@@ -50,12 +50,12 @@ CHECK_SUBSAMPLE_DEF(CryptoPlugin); 


DescramblerImpl::DescramblerImpl(

        const sp<SharedLibrary>& library, DescramblerPlugin *plugin) :

        mLibrary(library), mPlugin(plugin) {

    ALOGV("CTOR: mPlugin=%p", mPlugin);

        mLibrary(library), mPluginHolder(plugin) {

    ALOGV("CTOR: plugin=%p", mPluginHolder.get());

}



DescramblerImpl::~DescramblerImpl() {

    ALOGV("DTOR: mPlugin=%p", mPlugin);

    ALOGV("DTOR: plugin=%p", mPluginHolder.get());

    release();

}
@@ -63,12 +63,22 @@ Return<Status> DescramblerImpl::setMediaCasSession(const HidlCasSessionId& sessi 
    ALOGV("%s: sessionId=%s", __FUNCTION__,

            sessionIdToString(sessionId).string());



    return toStatus(mPlugin->setMediaCasSession(sessionId));

    std::shared_ptr<DescramblerPlugin> holder = std::atomic_load(&mPluginHolder);

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

        return toStatus(INVALID_OPERATION);

    }



    return toStatus(holder->setMediaCasSession(sessionId));

}



Return<bool> DescramblerImpl::requiresSecureDecoderComponent(

        const hidl_string& mime) {

    return mPlugin->requiresSecureDecoderComponent(String8(mime.c_str()));

    std::shared_ptr<DescramblerPlugin> holder = std::atomic_load(&mPluginHolder);

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

        return false;

    }



    return holder->requiresSecureDecoderComponent(String8(mime.c_str()));

}



static inline bool validateRangeForSize(
@@ -86,12 +96,23 @@ Return<void> DescramblerImpl::descramble( 
        descramble_cb _hidl_cb) {

    ALOGV("%s", __FUNCTION__);



    // Get a local copy of the shared_ptr for the plugin. Note that before

    // calling the HIDL callback, this shared_ptr must be manually reset,

    // since the client side could proceed as soon as the callback is called

    // without waiting for this method to go out of scope.

    std::shared_ptr<DescramblerPlugin> holder = std::atomic_load(&mPluginHolder);

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

        _hidl_cb(toStatus(INVALID_OPERATION), 0, NULL);

        return Void();

    }



    sp<IMemory> srcMem = mapMemory(srcBuffer.heapBase);



    // Validate if the offset and size in the SharedBuffer is consistent with the

    // mapped ashmem, since the offset and size is controlled by client.

    if (srcMem == NULL) {

        ALOGE("Failed to map src buffer.");

        holder.reset();

        _hidl_cb(toStatus(BAD_VALUE), 0, NULL);

        return Void();

    }
@@ -100,6 +121,7 @@ Return<void> DescramblerImpl::descramble( 
        ALOGE("Invalid src buffer range: offset %llu, size %llu, srcMem size %llu",

                srcBuffer.offset, srcBuffer.size, (uint64_t)srcMem->getSize());

        android_errorWriteLog(0x534e4554, "67962232");

        holder.reset();

        _hidl_cb(toStatus(BAD_VALUE), 0, NULL);

        return Void();

    }
@@ -117,6 +139,7 @@ Return<void> DescramblerImpl::descramble( 
                "srcOffset %llu, totalBytesInSubSamples %llu, srcBuffer size %llu",

                srcOffset, totalBytesInSubSamples, srcBuffer.size);

        android_errorWriteLog(0x534e4554, "67962232");

        holder.reset();

        _hidl_cb(toStatus(BAD_VALUE), 0, NULL);

        return Void();

    }
@@ -135,6 +158,7 @@ Return<void> DescramblerImpl::descramble( 
                    "dstOffset %llu, totalBytesInSubSamples %llu, srcBuffer size %llu",

                    dstOffset, totalBytesInSubSamples, srcBuffer.size);

            android_errorWriteLog(0x534e4554, "67962232");

            holder.reset();

            _hidl_cb(toStatus(BAD_VALUE), 0, NULL);

            return Void();

        }
@@ -146,7 +170,7 @@ Return<void> DescramblerImpl::descramble( 
    // Casting hidl SubSample to DescramblerPlugin::SubSample, but need

    // to ensure structs are actually idential



    int32_t result = mPlugin->descramble(

    int32_t result = holder->descramble(

            dstBuffer.type != BufferType::SHARED_MEMORY,

            (DescramblerPlugin::ScramblingControl)scramblingControl,

            subSamples.size(),
@@ -157,17 +181,17 @@ Return<void> DescramblerImpl::descramble( 
            dstOffset,

            NULL);



    holder.reset();

    _hidl_cb(toStatus(result >= 0 ? OK : result), result, NULL);

    return Void();

}



Return<Status> DescramblerImpl::release() {

    ALOGV("%s: mPlugin=%p", __FUNCTION__, mPlugin);

    ALOGV("%s: plugin=%p", __FUNCTION__, mPluginHolder.get());



    std::shared_ptr<DescramblerPlugin> holder(nullptr);

    std::atomic_store(&mPluginHolder, holder);



    if (mPlugin != NULL) {

        delete mPlugin;

        mPlugin = NULL;

    }

    return Status::OK;

}

cas/1.0/default/DescramblerImpl.h

+1 −1
Original line number Diff line number Diff line
@@ -55,7 +55,7 @@ public: 


private:

    sp<SharedLibrary> mLibrary;

    DescramblerPlugin *mPlugin;

    std::shared_ptr<DescramblerPlugin> mPluginHolder;



    DISALLOW_EVIL_CONSTRUCTORS(DescramblerImpl);

};