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##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2018 Michalis Pappas <mpappas@fastmail.fm>
##
## This program 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 for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, see <http://www.gnu.org/licenses/>.
##
import sigrokdecode as srd
WORD_ADDR_RESET = 0x00
WORD_ADDR_SLEEP = 0x01
WORD_ADDR_IDLE = 0x02
WORD_ADDR_COMMAND = 0x03
WORD_ADDR = {0x00: 'RESET', 0x01: 'SLEEP', 0x02: 'IDLE', 0x03: 'COMMAND'}
OPCODE_COUNTER = 0x24
OPCODE_DERIVE_KEY = 0x1c
OPCODE_DEV_REV = 0x30
OPCODE_ECDH = 0x43
OPCODE_GEN_DIG = 0x15
OPCODE_GEN_KEY = 0x40
OPCODE_HMAC = 0x11
OPCODE_CHECK_MAC = 0x28
OPCODE_LOCK = 0x17
OPCODE_MAC = 0x08
OPCODE_NONCE = 0x16
OPCODE_PAUSE = 0x01
OPCODE_PRIVWRITE = 0x46
OPCODE_RANDOM = 0x1b
OPCODE_READ = 0x02
OPCODE_SHA = 0x47
OPCODE_SIGN = 0x41
OPCODE_UPDATE_EXTRA = 0x20
OPCODE_VERIFY = 0x45
OPCODE_WRITE = 0x12
OPCODES = {
0x01: 'Pause',
0x02: 'Read',
0x08: 'MAC',
0x11: 'HMAC',
0x12: 'Write',
0x15: 'GenDig',
0x16: 'Nonce',
0x17: 'Lock',
0x1b: 'Random',
0x1c: 'DeriveKey',
0x20: 'UpdateExtra',
0x24: 'Counter',
0x28: 'CheckMac',
0x30: 'DevRev',
0x40: 'GenKey',
0x41: 'Sign',
0x43: 'ECDH',
0x45: 'Verify',
0x46: 'PrivWrite',
0x47: 'SHA',
}
ZONE_CONFIG = 0x00
ZONE_OTP = 0x01
ZONE_DATA = 0x02
ZONES = {0x00: 'CONFIG', 0x01: 'OTP', 0x02: 'DATA'}
STATUS_SUCCESS = 0x00
STATUS_CHECKMAC_FAIL = 0x01
STATUS_PARSE_ERROR = 0x03
STATUS_EXECUTION_ERROR = 0x0f
STATUS_READY = 0x11
STATUS_CRC_COMM_ERROR = 0xff
STATUS = {
0x00: 'Command success',
0x01: 'Checkmac failure',
0x03: 'Parse error',
0x0f: 'Execution error',
0x11: 'Ready',
0xff: 'CRC / communications error',
}
class Decoder(srd.Decoder):
api_version = 3
id = 'atsha204a'
name = 'ATSHA204A'
longname = 'Microchip ATSHA204A'
desc = 'Microchip ATSHA204A crypto authentication protocol.'
license = 'gplv2+'
inputs = ['i2c']
outputs = []
tags = ['Security/crypto', 'IC', 'Memory']
annotations = (
('waddr', 'Word address'),
('count', 'Count'),
('opcode', 'Opcode'),
('param1', 'Param1'),
('param2', 'Param2'),
('data', 'Data'),
('crc', 'CRC'),
('status', 'Status'),
('warning', 'Warning'),
)
annotation_rows = (
('frame', 'Frame', (0, 1, 2, 3, 4, 5, 6)),
('status', 'Status', (7,)),
('warnings', 'Warnings', (8,)),
)
def __init__(self):
self.reset()
def reset(self):
self.state = 'IDLE'
self.waddr = self.opcode = -1
self.ss_block = self.es_block = 0
self.bytes = []
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
def output_tx_bytes(self):
b = self.bytes
if len(b) < 1: # Ignore wakeup.
return
self.waddr = b[0][2]
self.put_waddr(b[0])
if self.waddr == WORD_ADDR_COMMAND:
count = b[1][2]
self.put_count(b[1])
if len(b) - 1 != count:
self.put_warning(b[0][0], b[-1][1],
'Invalid frame length: Got {}, expecting {} '.format(
len(b) - 1, count))
return
self.opcode = b[2][2]
self.put_opcode(b[2])
self.put_param1(b[3])
self.put_param2([b[4], b[5]])
self.put_data(b[6:-2])
self.put_crc([b[-2], b[-1]])
def output_rx_bytes(self):
b = self.bytes
count = b[0][2]
self.put_count(b[0])
if self.waddr == WORD_ADDR_RESET:
self.put_data([b[1]])
self.put_crc([b[2], b[3]])
self.put_status(b[0][0], b[-1][1], b[1][2])
elif self.waddr == WORD_ADDR_COMMAND:
if count == 4: # Status / Error.
self.put_data([b[1]])
self.put_crc([b[2], b[3]])
self.put_status(b[0][0], b[-1][1], b[1][2])
else:
self.put_data(b[1:-2])
self.put_crc([b[-2], b[-1]])
def putx(self, s, data):
self.put(s[0], s[1], self.out_ann, data)
def puty(self, s, data):
self.put(s[0][0], s[1][1], self.out_ann, data)
def putz(self, ss, es, data):
self.put(ss, es, self.out_ann, data)
def put_waddr(self, s):
self.putx(s, [0, ['Word addr: %s' % WORD_ADDR[s[2]]]])
def put_count(self, s):
self.putx(s, [1, ['Count: %s' % s[2]]])
def put_opcode(self, s):
self.putx(s, [2, ['Opcode: %s' % OPCODES[s[2]]]])
def put_param1(self, s):
op = self.opcode
if op in (OPCODE_CHECK_MAC, OPCODE_COUNTER, OPCODE_DEV_REV, \
OPCODE_ECDH, OPCODE_GEN_KEY, OPCODE_HMAC, OPCODE_MAC, \
OPCODE_NONCE, OPCODE_RANDOM, OPCODE_SHA, OPCODE_SIGN, \
OPCODE_VERIFY):
self.putx(s, [3, ['Mode: %02X' % s[2]]])
elif op == OPCODE_DERIVE_KEY:
self.putx(s, [3, ['Random: %s' % s[2]]])
elif op == OPCODE_PRIVWRITE:
self.putx(s, [3, ['Encrypted: {}'.format('Yes' if s[2] & 0x40 else 'No')]])
elif op == OPCODE_GEN_DIG:
self.putx(s, [3, ['Zone: %s' % ZONES[s[2]]]])
elif op == OPCODE_LOCK:
self.putx(s, [3, ['Zone: {}, Summary: {}'.format(
'DATA/OTP' if s[2] else 'CONFIG',
'Ignored' if s[2] & 0x80 else 'Used')]])
elif op == OPCODE_PAUSE:
self.putx(s, [3, ['Selector: %02X' % s[2]]])
elif op == OPCODE_READ:
self.putx(s, [3, ['Zone: {}, Length: {}'.format(ZONES[s[2] & 0x03],
'32 bytes' if s[2] & 0x90 else '4 bytes')]])
elif op == OPCODE_WRITE:
self.putx(s, [3, ['Zone: {}, Encrypted: {}, Length: {}'.format(ZONES[s[2] & 0x03],
'Yes' if s[2] & 0x40 else 'No', '32 bytes' if s[2] & 0x90 else '4 bytes')]])
else:
self.putx(s, [3, ['Param1: %02X' % s[2]]])
def put_param2(self, s):
op = self.opcode
if op == OPCODE_DERIVE_KEY:
self.puty(s, [4, ['TargetKey: {:02x} {:02x}'.format(s[1][2], s[0][2])]])
elif op in (OPCODE_COUNTER, OPCODE_ECDH, OPCODE_GEN_KEY, OPCODE_PRIVWRITE, \
OPCODE_SIGN, OPCODE_VERIFY):
self.puty(s, [4, ['KeyID: {:02x} {:02x}'.format(s[1][2], s[0][2])]])
elif op in (OPCODE_NONCE, OPCODE_PAUSE, OPCODE_RANDOM):
self.puty(s, [4, ['Zero: {:02x} {:02x}'.format(s[1][2], s[0][2])]])
elif op in (OPCODE_HMAC, OPCODE_MAC, OPCODE_CHECK_MAC, OPCODE_GEN_DIG):
self.puty(s, [4, ['SlotID: {:02x} {:02x}'.format(s[1][2], s[0][2])]])
elif op == OPCODE_LOCK:
self.puty(s, [4, ['Summary: {:02x} {:02x}'.format(s[1][2], s[0][2])]])
elif op in (OPCODE_READ, OPCODE_WRITE):
self.puty(s, [4, ['Address: {:02x} {:02x}'.format(s[1][2], s[0][2])]])
elif op == OPCODE_UPDATE_EXTRA:
self.puty(s, [4, ['NewValue: {:02x}'.format(s[0][2])]])
else:
self.puty(s, [4, ['-']])
def put_data(self, s):
if len(s) == 0:
return
op = self.opcode
if op == OPCODE_CHECK_MAC:
self.putz(s[0][0], s[31][1], [5, ['ClientChal: %s' % ' '.join(format(i[2], '02x') for i in s[0:32])]])
self.putz(s[32][0], s[63][1], [5, ['ClientResp: %s' % ' '.join(format(i[2], '02x') for i in s[32:64])]])
self.putz(s[64][0], s[76][1], [5, ['OtherData: %s' % ' '.join(format(i[2], '02x') for i in s[64:77])]])
elif op == OPCODE_DERIVE_KEY:
self.putz(s[0][0], s[31][1], [5, ['MAC: %s' % ' '.join(format(i[2], '02x') for i in s)]])
elif op == OPCODE_ECDH:
self.putz(s[0][0], s[31][1], [5, ['Pub X: %s' % ' '.join(format(i[2], '02x') for i in s[0:32])]])
self.putz(s[32][0], s[63][1], [5, ['Pub Y: %s' % ' '.join(format(i[2], '02x') for i in s[32:64])]])
elif op in (OPCODE_GEN_DIG, OPCODE_GEN_KEY):
self.putz(s[0][0], s[3][1], [5, ['OtherData: %s' % ' '.join(format(i[2], '02x') for i in s)]])
elif op == OPCODE_MAC:
self.putz(s[0][0], s[31][1], [5, ['Challenge: %s' % ' '.join(format(i[2], '02x') for i in s)]])
elif op == OPCODE_PRIVWRITE:
if len(s) > 36: # Key + MAC.
self.putz(s[0][0], s[-35][1], [5, ['Value: %s' % ' '.join(format(i[2], '02x') for i in s)]])
self.putz(s[-32][0], s[-1][1], [5, ['MAC: %s' % ' '.join(format(i[2], '02x') for i in s)]])
else: # Just value.
self.putz(s[0][0], s[-1][1], [5, ['Value: %s' % ' '.join(format(i[2], '02x') for i in s)]])
elif op == OPCODE_VERIFY:
if len(s) >= 64: # ECDSA components (always present)
self.putz(s[0][0], s[31][1], [5, ['ECDSA R: %s' % ' '.join(format(i[2], '02x') for i in s[0:32])]])
self.putz(s[32][0], s[63][1], [5, ['ECDSA S: %s' % ' '.join(format(i[2], '02x') for i in s[32:64])]])
if len(s) == 83: # OtherData (follow ECDSA components in validate / invalidate mode)
self.putz(s[64][0], s[82][1], [5, ['OtherData: %s' % ' '.join(format(i[2], '02x') for i in s[64:83])]])
if len(s) == 128: # Public key components (follow ECDSA components in external mode)
self.putz(s[64][0], s[95][1], [5, ['Pub X: %s' % ' '.join(format(i[2], '02x') for i in s[64:96])]])
self.putz(s[96][0], s[127][1], [5, ['Pub Y: %s' % ' '.join(format(i[2], '02x') for i in s[96:128])]])
elif op == OPCODE_WRITE:
if len(s) > 32: # Value + MAC.
self.putz(s[0][0], s[-31][1], [5, ['Value: %s' % ' '.join(format(i[2], '02x') for i in s)]])
self.putz(s[-32][0], s[-1][1], [5, ['MAC: %s' % ' '.join(format(i[2], '02x') for i in s)]])
else: # Just value.
self.putz(s[0][0], s[-1][1], [5, ['Value: %s' % ' '.join(format(i[2], '02x') for i in s)]])
else:
self.putz(s[0][0], s[-1][1], [5, ['Data: %s' % ' '.join(format(i[2], '02x') for i in s)]])
def put_crc(self, s):
self.puty(s, [6, ['CRC: {:02X} {:02X}'.format(s[0][2], s[1][2])]])
def put_status(self, ss, es, status):
self.putz(ss, es, [7, ['Status: %s' % STATUS[status]]])
def put_warning(self, ss, es, msg):
self.putz(ss, es, [8, ['Warning: %s' % msg]])
def decode(self, ss, es, data):
cmd, databyte = data
# State machine.
if self.state == 'IDLE':
# Wait for an I²C START condition.
if cmd != 'START':
return
self.state = 'GET SLAVE ADDR'
self.ss_block = ss
elif self.state == 'GET SLAVE ADDR':
# Wait for an address read/write operation.
if cmd == 'ADDRESS READ':
self.state = 'READ REGS'
elif cmd == 'ADDRESS WRITE':
self.state = 'WRITE REGS'
elif self.state == 'READ REGS':
if cmd == 'DATA READ':
self.bytes.append([ss, es, databyte])
elif cmd == 'STOP':
self.es_block = es
# Reset the opcode before received data, as this causes
# responses to be displayed incorrectly.
self.opcode = -1
if len(self.bytes) > 0:
self.output_rx_bytes()
self.waddr = -1
self.bytes = []
self.state = 'IDLE'
elif self.state == 'WRITE REGS':
if cmd == 'DATA WRITE':
self.bytes.append([ss, es, databyte])
elif cmd == 'STOP':
self.es_block = es
self.output_tx_bytes()
self.bytes = []
self.state = 'IDLE'
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