Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 1d5c36d8 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 e72ff02b

media/extractors/mp4/MPEG4Extractor.cpp

+13 −3
Original line number Diff line number Diff line
@@ -157,6 +157,7 @@ private: 


    MediaBufferHelper *mBuffer;



    size_t mSrcBufferSize;

    uint8_t *mSrcBuffer;



    bool mIsHeif;
@@ -5083,6 +5084,7 @@ MPEG4Source::MPEG4Source( 
      mNALLengthSize(0),

      mStarted(false),

      mBuffer(NULL),

      mSrcBufferSize(0),

      mSrcBuffer(NULL),

      mItemTable(itemTable),

      mElstShiftStartTicks(elstShiftStartTicks),
@@ -5264,6 +5266,7 @@ media_status_t MPEG4Source::start() { 
        // file probably specified a bad max size

        return AMEDIA_ERROR_MALFORMED;

    }

    mSrcBufferSize = max_size;



    mStarted = true;
@@ -5280,6 +5283,7 @@ media_status_t MPEG4Source::stop() { 
        mBuffer = NULL;

    }



    mSrcBufferSize = 0;

    delete[] mSrcBuffer;

    mSrcBuffer = NULL;
@@ -6467,13 +6471,19 @@ media_status_t MPEG4Source::read( 
        // Whole NAL units are returned but each fragment is prefixed by

        // the start code (0x00 00 00 01).

        ssize_t num_bytes_read = 0;

        bool mSrcBufferFitsDataToRead = size <= mSrcBufferSize;

        if (mSrcBufferFitsDataToRead) {

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

        } else {

          // We are trying to read a sample larger than the expected max sample size.

          // Fall through and let the failure be handled by the following if.

          android_errorWriteLog(0x534e4554, "188893559");

        }



        if (num_bytes_read < (ssize_t)size) {

            mBuffer->release();

            mBuffer = NULL;



            return AMEDIA_ERROR_IO;

            return mSrcBufferFitsDataToRead ? AMEDIA_ERROR_IO : AMEDIA_ERROR_MALFORMED;

        }



        uint8_t *dstData = (uint8_t *)mBuffer->data();