Code:  ssize_t MPEG4DataSource::readAt(off64_t offset, void *data, size_t size) {
     Mutex::Autolock autoLock(mLock);
 
    if (offset >= mCachedOffset
            && offset + size <= mCachedOffset + mCachedSize) {
         memcpy(data, &mCache[offset - mCachedOffset], size);
         return size;
     }

 return mSource->readAt(offset, data, size);
}

Vulnerability Type: Exec Code Overflow 
CWE ID: CWE-119
Summary: Multiple buffer overflows in MPEG4Extractor.cpp in libstagefright in Android before 5.1.1 LMY48I allow remote attackers to execute arbitrary code via invalid size values of NAL units in MP4 data, aka internal bug 19641538.
Commit Message: Add AUtils::isInRange, and use it to detect malformed MPEG4 nal sizes

Bug: 19641538
Change-Id: I5aae3f100846c125decc61eec7cd6563e3f33777
