radare2: Uncontrolled resource consumption in radare2 PEF loader

radare2 is a UNIX-like reverse engineering framework and command-line toolset. Prior to 6.2.0, radare2's Apple Preferred Executable Format loader was vulnerable because the PEF loader accepted relocSecCount values that were not bounded by the number of sections or complete relocation records in the input. The vulnerability is triggered by normal binary-format auto-detection of a small crafted Apple PEF file. The loader could perform up to 268,435,456 relocation-section iterations and repeated buffer operations after record offsets passed the end of the file. This can cause denial of service through excessive CPU consumption and prolonged processing. This issue is fixed in version 6.2.0.