impl `FromMdbValue` for bool is unsound

The implementation of FromMdbValue has several unsoundness issues. First of all, it allows to reinterpret arbitrary bytes as a bool and could make undefined behavior happen with safe function. Secondly, it allows transmuting pointer without taking memory layout into consideration. The details of...

qpdf:dct_fuzzer: Use-of-uninitialized-value in ycck_cmyk_convert

Detailed Report: https://oss-fuzz.com/testcase?key=5646580451639296 Project: qpdf Fuzzing Engine: libFuzzer Fuzz Target: dctfuzzer Job Type: libfuzzermsanqpdf Platform Id: linux Crash Type: Use-of-uninitialized-value Crash Address: Crash State: ycckcmykconvert sepupsample processdatasimplemain...