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|
#! /bin/sh
# vim: set tabstop=4 syntax=sh :
# SPDX-License-Identifier: GPL-2.0-or-later
#######################################################################################################
# #
# add AVM's header to a FIT image file #
# #
###################################################################################################VER#
# #
# fit-add-avm-header, version 0.2 #
# #
# This script is a part of the YourFritz project from https://github.com/PeterPawn/YourFritz. #
# #
###################################################################################################CPY#
# #
# Copyright (C) 2022 P.Haemmerlein (peterpawn@yourfritz.de) #
# #
###################################################################################################LIC#
# #
# This project is free software, you can redistribute it and/or modify it under the terms of the GNU #
# General Public License as published by the Free Software Foundation; either version 2 of the #
# License, or (at your option) any later version. #
# #
# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without #
# even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU #
# General Public License under http://www.gnu.org/licenses/gpl-2.0.html for more details. #
# #
#######################################################################################################
# #
# This script takes a FIT image built with U-boot's 'mkimage' command and adds a header using AVM's #
# extension format. #
# The data part, which looks like a cryptographic signature to me, will be filled with zeros. #
# #
#######################################################################################################
# #
# the whole logic as a sealed sub-function #
# #
#######################################################################################################
add_avm_header()
(
printf_ss() {
mask="$1"
shift
# shellcheck disable=SC2059
printf -- "$mask" "$@"
}
result() {
[ "$dbg" = "1" ] || return 0
if [ "$1" = "0" ]; then
color="$__yf_ansi_bright_green__"
elif [ "$1" = "1" ]; then
color="$__yf_ansi_bright_red__"
else
color="$__yf_ansi_yellow__"
fi
shift
printf -- "%s" "$color" 1>&2
debug "$@"
printf -- "%s\n" "$__yf_ansi_reset__" 1>&2
}
debug() {
[ "$dbg" = "1" ] || return 0
printf_ss "$@" 1>&2
}
sbo() (
sbo_ro()
{
v1=0; v2=0; v3=0; v4=0
while read -r p _ rt; do
[ "$p" -gt 5 ] && exit 1
[ "$p" -eq 5 ] && [ "$rt" -ne 0377 ] && exit 1
if [ "$p" -eq 5 ]; then
for i in $v4 $v3 $v2 $v1; do
printf -- "%b" "\0$(printf -- "%o" "$i")"
done
exit 0
fi
eval "v$p"=$(( 0$rt ))
done
exit 1
}
( cat; printf -- "%b" "\377" ) | cmp -l -- "$zeros" - 2>"$null" | sbo_ro
)
b2d() (
b2d_ro()
{
i=1; v=0; ff=0
while read -r p _ rt; do
if [ "$ff" -eq 1 ]; then
v=$(( v * 256 ))
ff=255
v=$(( v + ff ))
i=$(( i + 1 ))
ff=0
fi
while [ "$i" -lt "$p" ]; do
v=$(( v * 256 ))
i=$(( i + 1 ))
done
if [ "$rt" = 377 ] && [ $ff -eq 0 ]; then
ff=1
continue
fi
v=$(( v * 256 ))
rt=$(( 0$rt ))
v=$(( v + rt ))
i=$(( p + 1 ))
done
printf -- "%d" $v
}
( cat; printf -- "%b" "\377" ) | cmp -l -- "$zeros" - 2>"$null" | b2d_ro
return 0
)
get_data() ( dd if="$1" bs="$3" count=$(( ( $2 / $3 ) + 1 )) skip=1 2>"$null" | dd bs=1 count="$2" 2>"$null"; )
get_fdt32() ( get_data "$1" 4 "$2" | b2d; )
__yf_ansi_sgr() { printf -- '\033[%sm' "$1"; }
__yf_ansi_bold__="$(__yf_ansi_sgr 1)"
__yf_ansi_yellow__="$(__yf_ansi_sgr 33)"
__yf_ansi_bright_red__="$(__yf_ansi_sgr 91)"
__yf_ansi_bright_green__="$(__yf_ansi_sgr 92)"
__yf_ansi_reset__="$(__yf_ansi_sgr 0)"
__yf_get_script_lines() {
sed -n -e "/^#*${1}#\$/,/^#\{20\}.*#\$/p" -- "$0" | \
sed -e '1d;$d' | \
sed -e 's|# \(.*\) *#$|\1|' | \
sed -e 's|^#*#$|--|p' | \
sed -e '$d' | \
sed -e 's| *$||'
}
__yf_show_script_name() {
[ -n "$1" ] && printf -- '%s' "$1"
printf -- '%s' "${0#*/}"
[ -n "$1" ] && printf -- "%s" "${__yf_ansi_reset__}"
}
__yf_show_license() { __yf_get_script_lines 'LIC'; }
__yf_show_version() {
printf -- "\n%s%s%s, " "${__yf_ansi_bold__}" "$(__yf_get_script_lines 'VER' | sed -n -e "2s|^\([^,]*\),.*|\1|p")" "${__yf_ansi_reset__}"
v_display="$(__yf_get_script_lines 'VER' | sed -n -e "2s|^[^,]*, \(.*\)|\1|p")"
printf -- "%s\n" "$v_display"
}
__yf_show_copyright() { __yf_get_script_lines 'CPY'; }
usage() {
exec 1>&2
__yf_show_version
__yf_show_copyright
__yf_show_license
printf -- "\n"
printf -- "%sfit-add-avm-header.sh%s - add AVM's header to a (standard) FIT image file\n\n" "${__yf_ansi_bold__}" "${__yf_ansi_reset__}"
printf -- "Usage: %s [ options ] <standard-fit-image>\n\n" "$0"
printf -- "Options:\n\n"
printf -- "-d or --debug - show some extra info on STDERR\n"
printf -- "\n"
exec 1>&2
}
null="/dev/null"
zeros="/dev/zero"
fdt32_size=4
dbg=0
while [ "$(expr "$1" : "\(.\).*")" = "-" ]; do
[ "$1" = "--" ] && shift && break
if [ "$1" = "-d" ] || [ "$1" = "--debug" ]; then
dbg=1
shift
elif [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
usage
exit 0
else
printf -- "Unknown option: %s\a\n" "$1" 1>&2 && exit 1
fi
done
img="$1"
if [ "$dbg" = "1" ]; then
__yf_show_version 1>&2
__yf_show_copyright 1>&2
debug "\n"
fi
[ -z "$img" ] && printf -- "Missing input source parameter.\a\n" 1>&2 && exit 1
debug "Input file: %s%s%s\n" "$__yf_ansi_bright_green__" "$img" "$__yf_ansi_reset__"
debug "Looking for FDT magic value at offset 0x00 ..."
fdt_magic="$(dd if="$img" bs=4 count=1 2>"$null" | b2d)"
if { [ "$fdt_magic" -gt 0 ] && [ "$fdt_magic" -ne 3490578157 ]; } || { [ "$fdt_magic" -lt 0 ] && [ "$fdt_magic" -ne -804389139 ]; }; then
debug "$(result 1 " failed")"
printf -- "Invalid FDT magic at start of input file '%s'.\a\n" "$img" 1>&2
exit 1
else
debug "$(result 0 " OK")"
fi
offset=$(( fdt32_size ))
total_size="$(get_fdt32 "$img" "$offset")"
debug "FDT total size at offset 0x04: %s%u%s (%#x)\n" "$__yf_ansi_bright_green__" "$total_size" "$__yf_ansi_reset__" "$total_size"
[ -t 1 ] && printf -- "STDOUT is a terminal device, output suppressed.\a\n" 1>&2 && exit 1
magic="$(printf -- "\376\355\000\015" | sbo | b2d)"
debug "Writing magic value: 0x%08x ..." "$magic"
if printf -- "\376\355\000\015" | sbo; then
result 0 " OK"
else
result 1 " failed"
exit 1
fi
debug "Writing standard FIT image size: 0x%08x ..." "$(get_data "$img" "$offset" "$fdt32_size" | sbo | b2d)"
if dd if="$img" bs=4 skip=1 count=1 2>"$null" | sbo; then
result 0 " OK"
else
result 1 " failed"
exit 1
fi
# TODO: further investigations to find the algorithm used to fill this area
debug "Writing zeros to (assumed) signature area ..."
if dd if="$zeros" bs=64 count=1 2>"$null"; then
result 0 " OK"
else
result 1 " failed"
exit 1
fi
debug "Copying standard FIT data ..."
if dd if="$img" bs=$(( 1024 * 1024 )) 2>"$null"; then
result 0 " OK"
debug "\n"
else
result 1 " failed"
debug "\n"
exit 1
fi
debug "Appending 8 zero bytes after FDT payload ..."
if dd if="$zeros" bs=8 count=1 2>"$null"; then
result 0 " OK"
debug "\n"
else
result 1 " failed"
debug "\n"
exit 1
fi
exit 0
)
#######################################################################################################
# #
# invoke sealed function from above #
# #
#######################################################################################################
add_avm_header "$@"
#######################################################################################################
# #
# end of script #
# #
#######################################################################################################
|
