Commit e869a81a7a4be2415f60f29c55d8c5ad7e730aaa
2021-11-23T09:54:23
jdarith.c: Require cinfo->Se == DCTSIZE2 - 1 This fixes an oversight from the integration of the arithmetic entropy codec from libjpeg (66f97e6820e2cc9ef7429ea36285c80ffda87c8f). I chose to integrate the latest implementation available at the time, which was from jpeg-8b. However, I naively replaced cinfo->lim_Se with DCTSIZE2 - 1, not realizing that-- because of SmartScale-- jpeg-8b contains additional code (https://github.com/libjpeg-turbo/libjpeg-turbo/blob/jpeg-8b/jdinput.c#L249-L334) that guards against illegal values of cinfo->Se >= DCTSIZE2. Thus, libjpeg-turbo's implementation of arithmetic decoding has never guarded against such illegal values. This commit restores the relevant check from the original jpeg-6b arithmetic entropy codec patch ("jpeg-ari", 1e247ac854f8e33682bcfea475f6bccc42377208). Fixes #564