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Commit d13a4efc authored by Santiago Seifert's avatar Santiago Seifert
Browse files

Fix heap-buffer-overflow in MPEG4Extractor 

Caused by the extractor assuming that sample size will never exceed
the declared max input size (as in AMEDIAFORMAT_KEY_MAX_INPUT_SIZE).

Bug: 188893559
Test: Ran the fuzzer using the bug's testcase.
Change-Id: I31f2b9a4f1b561c4466c76ea2af8dd532622102a
Merged-In: I31f2b9a4f1b561c4466c76ea2af8dd532622102a
(cherry picked from commit 621f0e12)
parent 85c8c0aa

media/extractors/mp4/MPEG4Extractor.cpp

+10 −2
Original line number Diff line number Diff line
@@ -135,6 +135,7 @@ private: 


    bool mWantsNALFragments;



    size_t mSrcBufferSize;

    uint8_t *mSrcBuffer;



    bool mIsHeif;
@@ -3862,6 +3863,7 @@ MPEG4Source::MPEG4Source( 
      mGroup(NULL),

      mBuffer(NULL),

      mWantsNALFragments(false),

      mSrcBufferSize(0),

      mSrcBuffer(NULL),

      mIsHeif(itemTable != NULL),

      mItemTable(itemTable) {
@@ -3979,6 +3981,7 @@ status_t MPEG4Source::start(MetaDataBase *params) { 
        mGroup = NULL;

        return ERROR_MALFORMED;

    }

    mSrcBufferSize = max_size;



    mStarted = true;
@@ -3995,6 +3998,7 @@ status_t MPEG4Source::stop() { 
        mBuffer = NULL;

    }



    mSrcBufferSize = 0;

    delete[] mSrcBuffer;

    mSrcBuffer = NULL;
@@ -4913,11 +4917,15 @@ status_t MPEG4Source::read( 
        ssize_t num_bytes_read = 0;

        int32_t drm = 0;

        bool usesDRM = (mFormat.findInt32(kKeyIsDRM, &drm) && drm != 0);

        if (usesDRM) {

        if (usesDRM && size <= mBuffer->size()) {

            num_bytes_read =

                mDataSource->readAt(offset, (uint8_t*)mBuffer->data(), size);

        } else {

        } else if (!usesDRM && size <= mSrcBufferSize) {

            num_bytes_read = mDataSource->readAt(offset, mSrcBuffer, size);

        } else {

            // The sample is larger than the expected maximum size. Fall through and let the failure

            // be handled by the following if.

            android_errorWriteLog(0x534e4554, "188893559");

        }



        if (num_bytes_read < (ssize_t)size) {