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imgtool: Add support for dependency description 

This commit aims to add the ability to specify and add dependency
TLVs to MCUBOOT. Due to the private nature of this feature, having
dependency TLVs mean that the TLV Info header and these TLVs become
part of the protected area (they are supposed to get signed as well).
Since the TLV Info header containing the whole TLV section's size
becomes protected, this size needs to be calculated in advance to get
proper hash values.

Change-Id: I13277a3b595acc2bb8c5084420f3d61c8d301dc2
Author: Bence Kaposzta <bence.kaposzta@arm.com>
Signed-off-by: David Vincze <david.vincze@arm.com>
This commit is contained in:
David Vincze 2019-03-26 17:17:41 +01:00 committed by Fabio Utzig
parent 15aa6ef5ab
commit da8c91993d
2 changed files with 89 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

74
scripts/imgtool/image.py
View File

@ -1,5 +1,6 @@
# Copyright 2018 Nordic Semiconductor ASA
# Copyright 2017 Linaro Limited
# Copyright 2019 Arm Limited
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
@ -32,6 +33,8 @@ IMAGE_HEADER_SIZE = 32
BIN_EXT = "bin"
INTEL_HEX_EXT = "hex"
DEFAULT_MAX_SECTORS = 128
DEP_IMAGES_KEY = "images"
DEP_VERSIONS_KEY = "versions"
# Image header flags.
IMAGE_F = {
@ -48,6 +51,7 @@ TLV_VALUES = {
'ECDSA256': 0x22,
'ENCRSA2048': 0x30,
'ENCKW128': 0x31,
'DEPENDENCY': 0x40
}
TLV_INFO_SIZE = 4
@ -168,11 +172,49 @@ class Image():
len(self.payload), tsize, self.slot_size)
raise Exception(msg)
def create(self, key, enckey):
self.add_header(enckey)
def create(self, key, enckey, dependencies=None):
if dependencies is None:
dependencies_num = 0
protected_tlv_size = 0
else:
# Size of a Dependency TLV = Header ('BBH') + Payload('IBBHI')
# = 16 Bytes
dependencies_num = len(dependencies[DEP_IMAGES_KEY])
protected_tlv_size = (dependencies_num * 16) + TLV_INFO_SIZE
self.add_header(enckey, protected_tlv_size)
tlv = TLV(self.endian)
if protected_tlv_size != 0:
for i in range(dependencies_num):
e = STRUCT_ENDIAN_DICT[self.endian]
payload = struct.pack(
e + 'I'+'BBHI',
int(dependencies[DEP_IMAGES_KEY][i]),
dependencies[DEP_VERSIONS_KEY][i].major,
dependencies[DEP_VERSIONS_KEY][i].minor,
dependencies[DEP_VERSIONS_KEY][i].revision,
dependencies[DEP_VERSIONS_KEY][i].build
)
tlv.add('DEPENDENCY', payload)
# Full TLV size needs to be calculated in advance, because the
# header will be protected as well
tlv_header_size = 4
payload_digest_size = 32
keyhash_size = 32
cipherkey_size = 32
full_size = TLV_INFO_SIZE + len(tlv.buf) + tlv_header_size \
+ payload_digest_size
if key is not None:
full_size += tlv_header_size + keyhash_size \
+ tlv_header_size + key.sig_len()
if enckey is not None:
full_size += tlv_header_size + cipherkey_size
tlv_header = struct.pack(e + 'HH', TLV_INFO_MAGIC, full_size)
self.payload += tlv_header + bytes(tlv.buf)
# Note that ecdsa wants to do the hashing itself, which means
# we get to hash it twice.
sha = hashlib.sha256()
@ -208,9 +250,9 @@ class Image():
self.payload[self.header_size:] = encryptor.update(img) + \
encryptor.finalize()
self.payload += tlv.get()
self.payload += tlv.get()[protected_tlv_size:]
def add_header(self, enckey):
def add_header(self, enckey, protected_tlv_size):
"""Install the image header."""
flags = 0
@ -219,29 +261,29 @@ class Image():
e = STRUCT_ENDIAN_DICT[self.endian]
fmt = (e +
# type ImageHdr struct {
'I' + # Magic uint32
'I' + # LoadAddr uint32
'H' + # HdrSz uint16
'H' + # Pad1 uint16
'I' + # ImgSz uint32
'I' + # Flags uint32
'BBHI' + # Vers ImageVersion
'I' # Pad2 uint32
) # }
# type ImageHdr struct {
'I' + # Magic uint32
'I' + # LoadAddr uint32
'H' + # HdrSz uint16
'H' + # PTLVSz uint16
'I' + # ImgSz uint32
'I' + # Flags uint32
'BBHI' + # Vers ImageVersion
'I' # Pad1 uint32
) # }
assert struct.calcsize(fmt) == IMAGE_HEADER_SIZE
header = struct.pack(fmt,
IMAGE_MAGIC,
0, # LoadAddr
self.header_size,
0, # Pad1
protected_tlv_size, # TLV Info header + Dependency TLVs
len(self.payload) - self.header_size, # ImageSz
flags, # Flags
self.version.major,
self.version.minor or 0,
self.version.revision or 0,
self.version.build or 0,
0) # Pad2
0) # Pad1
self.payload = bytearray(self.payload)
self.payload[:len(header)] = header

33
scripts/imgtool/main.py
View File

@ -1,6 +1,7 @@
#! /usr/bin/env python3
#
# Copyright 2017 Linaro Limited
# Copyright 2019 Arm Limited
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
@ -14,6 +15,7 @@
# See the License for the specific language governing permissions and
# limitations under the License.
import re
import click
import getpass
import imgtool.keys as keys
@ -106,6 +108,29 @@ def validate_header_size(ctx, param, value):
return value
def get_dependencies(ctx, param, value):
if value is not None:
versions = []
images = re.findall(r"\((\d+)", value)
if len(images) == 0:
raise click.BadParameter(
"Image dependency format is invalid: {}".format(value))
raw_versions = re.findall(r",\s*([0-9.+]+)\)", value)
if len(images) != len(raw_versions):
raise click.BadParameter(
'''There's a mismatch between the number of dependency images
and versions in: {}'''.format(value))
for raw_version in raw_versions:
try:
versions.append(decode_version(raw_version))
except ValueError as e:
raise click.BadParameter("{}".format(e))
dependencies = dict()
dependencies[image.DEP_IMAGES_KEY] = images
dependencies[image.DEP_VERSIONS_KEY] = versions
return dependencies
class BasedIntParamType(click.ParamType):
name = 'integer'
@ -138,6 +163,9 @@ class BasedIntParamType(click.ParamType):
help='Add --header-size zeroed bytes at the beginning of the image')
@click.option('-H', '--header-size', callback=validate_header_size,
type=BasedIntParamType(), required=True)
@click.option('-d', '--dependencies', callback=get_dependencies,
required=False, help='''Add dependence on another image, format:
"(<image_ID>,<image_version>), ... "''')
@click.option('-v', '--version', callback=validate_version, required=True)
@click.option('--align', type=click.Choice(['1', '2', '4', '8']),
required=True)
@ -146,7 +174,8 @@ class BasedIntParamType(click.ParamType):
INFILE and OUTFILE are parsed as Intel HEX if the params have
.hex extension, othewise binary format is used''')
def sign(key, align, version, header_size, pad_header, slot_size, pad,
max_sectors, overwrite_only, endian, encrypt, infile, outfile):
max_sectors, overwrite_only, endian, encrypt, infile, outfile,
dependencies):
img = image.Image(version=decode_version(version), header_size=header_size,
pad_header=pad_header, pad=pad, align=int(align),
slot_size=slot_size, max_sectors=max_sectors,
@ -159,7 +188,7 @@ def sign(key, align, version, header_size, pad_header, slot_size, pad,
raise Exception("Encryption only available with RSA key")
if key and not isinstance(key, keys.RSA2048):
raise Exception("Signing only available with private RSA key")
img.create(key, enckey)
img.create(key, enckey, dependencies)
img.save(outfile)