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tool/compile_gatt:calculated GATT Database Hash

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This commit is contained in:
Matthias Ringwald 2020-01-12 21:14:32 +01:00
parent 285653b26b
commit 043f8832f5
1 changed files with 115 additions and 8 deletions
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123
tool/compile_gatt.py
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@ -1,12 +1,15 @@
#!/usr/bin/env python
#
# BLE GATT configuration generator for use with BTstack
# Copyright 2018 BlueKitchen GmbH
# Copyright 2019 BlueKitchen GmbH
#
# Format of input file:
# PRIMARY_SERVICE, SERVICE_UUID
# CHARACTERISTIC, ATTRIBUTE_TYPE_UUID, [READ | WRITE | DYNAMIC], VALUE
# dependencies:
# - pip3 install pycryptodomex
import codecs
import csv
import io
@ -17,6 +20,16 @@ import sys
import argparse
import tempfile
# try to import Cryptodome
try:
from Cryptodome2.Cipher import AES
from Cryptodome.Hash import CMAC
have_crypto = True
except ImportError:
have_crypto = False
print("\n[!] PyCryptodome required to calculate GATT Database Hash but not installed (using dummy hash value 00..00)")
print("[!] Please install PyCryptodome, e.g. 'pip install pycryptodomex'\n")
header = '''
// {0} generated from {1} for BTstack
// it needs to be regenerated when the .gatt file is updated.
@ -48,6 +61,7 @@ assigned_uuids = {
'GAP_RECONNECTION_ADDRESS' : 0x2A03,
'GAP_PERIPHERAL_PREFERRED_CONNECTION_PARAMETERS' : 0x2A04,
'GATT_SERVICE_CHANGED' : 0x2a05,
'GATT_DATABASE_HASH' : 0x2b2a
}
security_permsission = ['ANYBODY','ENCRYPTED', 'AUTHENTICATED', 'AUTHORIZED', 'AUTHENTICATED_SC']
@ -117,10 +131,20 @@ current_characteristic_uuid_string = ""
defines_for_characteristics = []
defines_for_services = []
include_paths = []
database_hash_message = bytearray()
handle = 1
total_size = 0
def aes_cmac(key, n):
if have_crypto:
cobj = CMAC.new(key, ciphermod=AES)
cobj.update(n)
return cobj.digest()
else:
# return dummy value
return b'\x00' * 16
def read_defines(infile):
defines = dict()
with open (infile, 'rt') as fin:
@ -276,6 +300,9 @@ def write_sequence(fout, text):
for part in parts:
fout.write("0x%s, " % (part.strip()))
def write_database_hash(fout):
fout.write("THE-DATABASE-HASH")
def write_indent(fout):
fout.write(" ")
@ -346,6 +373,20 @@ def dump_flags(fout, flags):
fout.write('ENCRYPTION_KEY_SIZE=%u' % encryption_key_size)
fout.write('\n')
def database_hash_append_uint8(value):
global database_hash_message
database_hash_message.append(value)
def database_hash_append_uint16(value):
global database_hash_message
database_hash_append_uint8(value & 0xff)
database_hash_append_uint8((value >> 8) & 0xff)
def database_hash_append_value(value):
global database_hash_message
for byte in value:
database_hash_append_uint8(byte)
def parseService(fout, parts, service_type):
global handle
global total_size
@ -375,6 +416,10 @@ def parseService(fout, parts, service_type):
write_uuid(fout, uuid)
fout.write("\n")
database_hash_append_uint16(handle)
database_hash_append_uint16(service_type)
database_hash_append_value(uuid)
current_service_uuid_string = c_string_for_uuid(parts[1])
current_service_start_handle = handle
handle = handle + 1
@ -416,6 +461,13 @@ def parseIncludeService(fout, parts):
write_uuid(fout, uuid)
fout.write("\n")
database_hash_append_uint16(handle)
database_hash_append_uint16(0x2802)
database_hash_append_uint16(services[keyUUID][0])
database_hash_append_uint16(services[keyUUID][1])
if uuid_size > 0:
database_hash_append_value(uuid)
handle = handle + 1
total_size = total_size + size
@ -466,11 +518,22 @@ def parseCharacteristic(fout, parts):
handle = handle + 1
total_size = total_size + size
database_hash_append_uint16(handle)
database_hash_append_uint16(0x2803)
database_hash_append_uint8(characteristic_properties)
database_hash_append_uint16(handle+1)
database_hash_append_value(uuid)
uuid_is_database_hash = len(uuid) == 2 and uuid[0] == 0x2a and uuid[1] == 0x2b
size = 2 + 2 + 2 + uuid_size
if is_string(value):
size = size + len(value)
if uuid_is_database_hash:
size += 16
else:
size = size + len(value.split())
if is_string(value):
size = size + len(value)
else:
size = size + len(value.split())
value_flags = att_flags(properties)
@ -488,10 +551,13 @@ def parseCharacteristic(fout, parts):
write_16(fout, value_flags)
write_16(fout, handle)
write_uuid(fout, uuid)
if is_string(value):
write_string(fout, value)
if uuid_is_database_hash:
write_database_hash(fout)
else:
write_sequence(fout,value)
if is_string(value):
write_string(fout, value)
else:
write_sequence(fout,value)
fout.write("\n")
defines_for_characteristics.append('#define ATT_CHARACTERISTIC_%s_VALUE_HANDLE 0x%04x' % (current_characteristic_uuid_string, handle))
@ -518,9 +584,14 @@ def parseCharacteristic(fout, parts):
write_16(fout, 0x2902)
write_16(fout, 0)
fout.write("\n")
database_hash_append_uint16(handle)
database_hash_append_uint16(0x2902)
defines_for_characteristics.append('#define ATT_CHARACTERISTIC_%s_CLIENT_CONFIGURATION_HANDLE 0x%04x' % (current_characteristic_uuid_string, handle))
handle = handle + 1
if properties & property_flags['RELIABLE_WRITE']:
size = 2 + 2 + 2 + 2 + 2
write_indent(fout)
@ -532,6 +603,11 @@ def parseCharacteristic(fout, parts):
write_16(fout, 0x2900)
write_16(fout, 1) # Reliable Write
fout.write("\n")
database_hash_append_uint16(handle)
database_hash_append_uint16(0x2900)
database_hash_append_uint16(1)
handle = handle + 1
def parseCharacteristicUserDescription(fout, parts):
@ -568,6 +644,10 @@ def parseCharacteristicUserDescription(fout, parts):
else:
write_sequence(fout,value)
fout.write("\n")
database_hash_append_uint16(handle)
database_hash_append_uint16(0x2901)
defines_for_characteristics.append('#define ATT_CHARACTERISTIC_%s_USER_DESCRIPTION_HANDLE 0x%04x' % (current_characteristic_uuid_string, handle))
handle = handle + 1
@ -596,6 +676,10 @@ def parseServerCharacteristicConfiguration(fout, parts):
write_16(fout, handle)
write_16(fout, 0x2903)
fout.write("\n")
database_hash_append_uint16(handle)
database_hash_append_uint16(0x2903)
defines_for_characteristics.append('#define ATT_CHARACTERISTIC_%s_SERVER_CONFIGURATION_HANDLE 0x%04x' % (current_characteristic_uuid_string, handle))
handle = handle + 1
@ -630,6 +714,10 @@ def parseCharacteristicFormat(fout, parts):
write_sequence(fout, name_space)
write_uuid(fout, description)
fout.write("\n")
database_hash_append_uint16(handle)
database_hash_append_uint16(0x2904)
handle = handle + 1
@ -654,6 +742,10 @@ def parseCharacteristicAggregateFormat(fout, parts):
sys.exit(1)
write_16(fout, format_handle)
fout.write("\n")
database_hash_append_uint16(handle)
database_hash_append_uint16(0x2905)
handle = handle + 1
def parseReportReference(fout, parts):
@ -930,11 +1022,26 @@ try:
parse(args.gattfile, fin, filename, sys.argv[0], ftemp)
listHandles(ftemp)
# calc GATT Database Hash
db_hash = aes_cmac(bytearray(16), database_hash_message)
if isinstance(db_hash, str):
# python2
db_hash_sequence = [('0x%02x' % ord(i)) for i in db_hash]
elif isinstance(db_hash, bytes):
# python3
db_hash_sequence = [('0x%02x' % i) for i in db_hash]
else:
print("AES CMAC returns unexpected type %s, abort" % type(db_hash))
sys.exit(1)
# reverse hash to get little endian
db_hash_sequence.reverse()
db_hash_string = ', '.join(db_hash_sequence) + ', '
# pass 2: insert GATT Database Hash
fout = open (filename, 'w')
ftemp.seek(0)
for line in ftemp:
fout.write(line)
fout.write(line.replace('THE-DATABASE-HASH', db_hash_string))
fout.close()
ftemp.close()