In FFmpeg 3.3.3, a DoS in cine_read_header() due to lack of an EOF check might cause huge CPU and memory consumption

In FFmpeg 3.3.3, a DoS in cine_read_header() due to lack of an EOF check might cause huge CPU and memory consumption. When a crafted CINE file, which claims a large "duration" field in the header but does not contain sufficient backing data, is provided, the image-offset parsing loop would consume huge CPU and memory resources, since there is no EOF check inside the loop.