fix: rewrite sanity check to handle malformed filesystem from D-Link. squashfs-tools maintainer introduced a sanity check with commits 3954bbb8e44f54a7081d84ddb968c2c2f210ad09 and 734a85f5f117c2d92829a1874b952efa6c1d4f4d. These checks means sasquatch can't extract squashfs v2 filesystems from D-Link. Reproduction samples can be found here: - http://legacyfiles.us.dlink.com/DIR-600L/REVA/FIRMWARE/ - http://legacyfiles.us.dlink.com/DIR-515/REVA/FIRMWARE/ I'm still not sure if the error lies on D-Link for building malformed images or squashfs-tools for confusing squashfs v2 and v3 super block content. At this point I don't care and chose to disable the sanity check while keeping overflows in check. I don't see any side effects in terms of memory access or usage.