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@mbolivar
Created March 1, 2019 22:49
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#!/usr/bin/env python3
# Copyright (c) 2018 Foundries.io
#
# SPDX-License-Identifier: Apache-2.0
import argparse
from collections import namedtuple
import struct
# Field names for mcuboot header, with struct image_version inlined,
# as well as struct module format string and reprs format strings for
# each.
IMG_HDR_FIELDS = [
'magic', 'load_addr', 'hdr_size', 'img_size', 'flags',
'ver_major', 'ver_minor', 'ver_revision', 'ver_build_num']
IMG_HDR_FMT = '<IIHxxIIbbhIxxxx'
IMG_HDR_MAGIC = 0x96f3b83d
IMAGE_F_RAM_LOAD = 0x00000020
TLV_INFO_FIELDS = ['magic', 'tlv_size']
TLV_INFO_FMT = '<HH'
TLV_INFO_SIZE = 4
TLV_INFO_MAGIC = 0x6907
TLV_HDR_FIELDS = ['type', 'len']
TLV_HDR_FMT = '<bxH'
TLV_HDR_SIZE = 4
TLV_HDR_TYPES = {
0x01: 'IMAGE_TLV_KEYHASH',
0x10: 'IMAGE_TLV_SHA256',
0x20: 'IMAGE_TLV_RSA2048_PSS',
0x21: 'IMAGE_TLV_ECDSA224',
0x22: 'IMAGE_TLV_ECDSA256'
}
class ImageHeader(namedtuple('ImageHeader', IMG_HDR_FIELDS)):
def __repr__(self):
return ('ImageHeader(magic={}/0x{:08X}, load_addr={}/0x{:08X}, '
'hdr_size=0x{:04X}, img_size={}/0x{:08X}, flags=0x{:08X}, '
'version="{}.{}.{}-build{}")').format(
'OK' if self._magic_ok() else 'BAD', self.magic,
'VALID' if self._load_addr_valid() else 'IGNORED',
self.load_addr,
self.hdr_size, self.img_size, self.img_size, self.flags,
self.ver_major, self.ver_minor, self.ver_revision,
self.ver_build_num)
def _magic_ok(self):
return self.magic == IMG_HDR_MAGIC
def _load_addr_valid(self):
return bool(self.flags & IMAGE_F_RAM_LOAD)
class TLVInfo(namedtuple('TLVInfo', TLV_INFO_FIELDS)):
def __repr__(self):
return 'TLVInfo(magic={}/0x{:04X}, tlv_size={})'.format(
'OK' if self._magic_ok() else 'BAD', self.magic, self.tlv_size)
def _magic_ok(self):
return self.magic == TLV_INFO_MAGIC
class TLVHeader(namedtuple('TLVHeader', TLV_HDR_FIELDS)):
def __repr__(self):
return 'TLVHeader(type={}/0x{:02X}, len={})'.format(
TLV_HDR_TYPES[self.type], self.type, self.len)
def main():
parser = argparse.ArgumentParser()
parser.add_argument('image')
args = parser.parse_args()
with open(args.image, 'rb') as f:
contents = f.read()
img_header = ImageHeader(*struct.unpack_from(IMG_HDR_FMT, contents))
print(img_header)
print('Initial image bytes:')
start = img_header.hdr_size
end = start + min(20, img_header.img_size)
print('\t' + ' '.join('{:02x}'.format(b) for b in contents[start:end]))
tlv_info_offset = img_header.hdr_size + img_header.img_size
tlv_info = TLVInfo(*struct.unpack_from(TLV_INFO_FMT, contents,
offset=tlv_info_offset))
print(tlv_info)
tlv_end = tlv_info_offset + tlv_info.tlv_size
tlv_off = tlv_info_offset + TLV_INFO_SIZE
tlv_num = 0
while tlv_off < tlv_end:
tlv_hdr = TLVHeader(*struct.unpack_from(TLV_HDR_FMT, contents,
offset=tlv_off))
print('TLV {}:'.format(tlv_num), tlv_hdr)
if tlv_hdr.len <= 32:
start = tlv_off + TLV_HDR_SIZE
end = start + tlv_hdr.len
print('\t' + ' '.join('{:02x}'.format(b) for b in
contents[start:end]))
tlv_off += TLV_HDR_SIZE + tlv_hdr.len
tlv_num += 1
if __name__ == '__main__':
main()
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