#!/bin/bash . lib.sh # # *** Description *** # # generate primary header with well-formed json but missing # trailing null byte. # # secondary header is corrupted on purpose as well # # $1 full target dir # $2 full source luks2 image PATTERN="\"config\":{" KEY="\"config_key\":\"" function generate() { read -r json_str < $TMPDIR/json0 json_len=${#json_str} pindex=$(strindex $json_str $PATTERN) test $pindex -gt 0 || exit 2 offset=${#PATTERN} offset=$((offset+pindex)) key_len=${#KEY} remain=$((LUKS2_JSON_SIZE*512-key_len-json_len-1)) # -1: closing '"' if [ ${json_str:offset:1} = "}" ]; then format_str="%s%s%s" else format_str="%s%s,%s" remain=$((remain-1)) # also count with separating ',' fi test $remain -gt 0 || exit 2 fill=$(repeat_str "X" $remain) fill=$(repeat_str "X" $remain)"\"" printf $format_str $KEY $fill ${json_str:$offset} | _dd of=$TMPDIR/json0 bs=1 seek=$offset conv=notrunc lib_mangle_json_hdr0_kill_hdr1 } function check() { lib_hdr1_killed || exit 2 lib_hdr0_checksum || exit 2 read_luks2_json0 $TGT_IMG $TMPDIR/json_res0 read -r json_str_res0 < $TMPDIR/json_res0 test ${#json_str_res0} -eq $((LUKS2_JSON_SIZE*512)) || exit 2 } lib_prepare $@ generate check lib_cleanup