Commit 6a522fcda46934b3dc2464114d1283f110105d5e
2024-05-02T14:07:45
jpegtran -drop: Ensure all quant tables defined It is possible to craft a malformed JPEG image in which all of the scans contain fewer components than the number of components specified in the Start Of Frame (SOF) segment. Attempting to use such an image as either an input image or a drop image with 'jpegtran -drop' caused a NULL dereference and subsequent segfault in transupp.c:adjust_quant(), so this commit adds appropriate checks to guard against that. Since the issue involved an interface that is only exposed on the jpegtran command line, it did not represent a security risk. 'jpegtran -drop' could not ever be used successfully with images such as the ones described above. This commit simply makes jpegtran fail gracefully rather than crash. Fixes #758