| #!/usr/bin/env python3 |
| # Copyright lowRISC contributors. |
| # Licensed under the Apache License, Version 2.0, see LICENSE for details. |
| # SPDX-License-Identifier: Apache-2.0 |
| r"""OTP memory image class, used to create preload images for the OTP |
| memory for simulations and FPGA emulation. |
| """ |
| |
| import logging as log |
| import random |
| |
| from lib.common import check_bool, check_int, ecc_encode, random_or_hexvalue |
| from lib.LcStEnc import LcStEnc |
| from lib.OtpMemMap import OtpMemMap |
| from lib.Present import Present |
| |
| # Seed diversification constant for OtpMemImg (this enables to use |
| # the same seed for different classes) |
| OTP_IMG_SEED_DIVERSIFIER = 1941661965323525198146 |
| |
| |
| def _present_64bit_encrypt(plain, key): |
| '''Scramble a 64bit block with PRESENT cipher''' |
| |
| # Make sure data is within 64bit range |
| assert (plain >= 0) and (plain < 2**64), \ |
| 'Data block is out of 64bit range' |
| |
| # Make sure key is within 128bit range |
| assert (key >= 0) and (key < 2**128), \ |
| 'Key is out of 128bit range' |
| |
| # Make sure inputs are integers |
| assert isinstance(plain, int) and isinstance(key, int), \ |
| 'Data and key need to be of type int' |
| |
| cipher = Present(key, rounds=32, keylen=128) |
| return cipher.encrypt(plain) |
| |
| |
| def _present_64bit_digest(data_blocks, iv, const): |
| '''Compute digest over multiple 64bit data blocks''' |
| |
| # We need to align the number of data blocks to 2x64bit |
| # for the digest to work properly. |
| if len(data_blocks) % 2 == 1: |
| data_blocks = data_blocks + [data_blocks[-1]] |
| |
| # This computes a digest according to a Merkle-Damgard construction |
| # that uses the Davies-Meyer scheme to turn the PRESENT cipher into |
| # a one-way compression function. Digest finalization consists of |
| # a final digest round with a 128bit constant. |
| # See also: https://docs.opentitan.org/hw/ip/otp_ctrl/doc/index.html#scrambling-datapath |
| state = iv |
| last_b64 = None |
| for b64 in data_blocks: |
| if last_b64 is None: |
| last_b64 = b64 |
| continue |
| |
| b128 = last_b64 + (b64 << 64) |
| state ^= _present_64bit_encrypt(state, b128) |
| last_b64 = None |
| |
| assert last_b64 is None |
| return state |
| |
| |
| def _to_hexfile_with_ecc(data, annotation, config): |
| '''Compute ECC and convert into memory hexfile''' |
| |
| log.info('Convert to HEX file.') |
| |
| data_width = config['secded']['data_width'] |
| assert data_width % 8 == 0, \ |
| 'OTP data width must be a multiple of 8' |
| assert data_width <= 64, \ |
| 'OTP data width cannot be larger than 64' |
| |
| num_words = len(data) * 8 // data_width |
| bytes_per_word = data_width // 8 |
| # Byte aligned total width after adding ECC bits |
| bytes_per_word_ecc = ( |
| (data_width + config['secded']['ecc_width'] + 7) // 8) |
| bin_format_str = '0' + str(data_width) + 'b' |
| hex_format_str = '0' + str(bytes_per_word_ecc * 2) + 'x' |
| memory_words = '// OTP memory hexfile with {} x {}bit layout\n'.format( |
| num_words, bytes_per_word_ecc * 8) |
| log.info('Memory layout is {} x {}bit (with ECC)'.format( |
| num_words, bytes_per_word_ecc * 8)) |
| |
| for k in range(num_words): |
| # Assemble native OTP word and uniquify annotation for comments |
| word = 0 |
| word_ann = {} |
| for j in range(bytes_per_word): |
| idx = k * bytes_per_word + j |
| word += data[idx] << (j * 8) |
| if annotation[idx] not in word_ann: |
| word_ann.update({annotation[idx]: "1"}) |
| |
| # This prints the byte offset of the corresponding |
| # payload data in the memory map (excluding ECC bits) |
| annotation_str = ' // {:06x}: '.format(k * bytes_per_word) + ', '.join( |
| word_ann.keys()) |
| |
| # ECC encode |
| word_bin = format(word, bin_format_str) |
| word_bin = ecc_encode(config, word_bin) |
| word_hex = format(int(word_bin, 2), hex_format_str) |
| memory_words += word_hex + annotation_str + '\n' |
| |
| log.info('Done.') |
| |
| return memory_words |
| |
| |
| def _check_unused_keys(dict_to_check, msg_postfix=""): |
| '''If there are unused keys, print their names and error out''' |
| for key in dict_to_check.keys(): |
| log.info("Unused key {} in {}".format(key, msg_postfix)) |
| if dict_to_check: |
| raise RuntimeError('Aborting due to unused keys in config dict') |
| |
| |
| class OtpMemImg(OtpMemMap): |
| |
| # LC state object |
| lc_state = [] |
| |
| def __init__(self, lc_state_config, otp_mmap_config, img_config): |
| |
| # Initialize memory map |
| super().__init__(otp_mmap_config) |
| |
| # Initialize the LC state and OTP memory map objects first, since |
| # validation and image generation depends on them |
| self.lc_state = LcStEnc(lc_state_config) |
| |
| # Validate memory image configuration |
| log.info('') |
| log.info('Parse OTP image specification.') |
| |
| # Encryption smoke test with known test vector |
| enc_test = _present_64bit_encrypt( |
| 0x0123456789abcdef, |
| 0x0123456789abcdef0123456789abcdef) |
| |
| assert enc_test == 0x0e9d28685e671dd6, \ |
| 'Encryption module test failed' |
| |
| otp_width = self.config['otp']['width'] * 8 |
| secded_width = self.lc_state.config['secded']['data_width'] |
| if otp_width != secded_width: |
| raise RuntimeError('OTP width and SECDED data width must be equal') |
| |
| if 'seed' not in img_config: |
| raise RuntimeError('Missing seed in configuration.') |
| |
| img_config['seed'] = check_int(img_config['seed']) |
| log.info('Seed: {0:x}'.format(img_config['seed'])) |
| log.info('') |
| |
| # Re-initialize with seed to make results reproducible. |
| random.seed(OTP_IMG_SEED_DIVERSIFIER + img_config['seed']) |
| |
| if 'partitions' not in img_config: |
| raise RuntimeError('Missing partitions key in configuration.') |
| |
| for part in img_config['partitions']: |
| self.merge_part_data(part) |
| log.info('Adding values to {} partition.'.format(part['name'])) |
| for item in part['items']: |
| self.merge_item_data(part, item) |
| |
| # Key accounting |
| img_config_check = img_config.copy() |
| del img_config_check['seed'] |
| del img_config_check['partitions'] |
| _check_unused_keys(img_config_check, 'in image config') |
| |
| log.info('') |
| log.info('Parsing OTP image successfully completed.') |
| |
| def merge_part_data(self, part): |
| '''This validates and merges the partition data into the memory map dict''' |
| |
| part.setdefault('items', []) |
| if not isinstance(part['items'], list): |
| raise RuntimeError('the "items" key must contain a list') |
| |
| # Check if partition name exists in memory map |
| part.setdefault('name', 'unknown_name') |
| mmap_part = self.get_part(part['name']) |
| if mmap_part is None: |
| raise RuntimeError('Partition {} does not exist'.format( |
| part['name'])) |
| |
| # Only partitions with a hardware digest can be locked. |
| part.setdefault('lock', 'false') |
| part['lock'] = check_bool(part['lock']) |
| if part['lock'] and not \ |
| mmap_part['hw_digest']: |
| raise RuntimeError( |
| 'Partition {} does not contain a hardware digest'.format( |
| part['name'])) |
| |
| # Augment memory map datastructure with lock bit. |
| mmap_part['lock'] = part['lock'] |
| |
| if part['name'] == 'LIFE_CYCLE': |
| part.setdefault('state', 'RAW') |
| part.setdefault('count', 0) |
| |
| part['count'] = check_int(part['count']) |
| if len(part['items']) > 0: |
| raise RuntimeError( |
| 'Life cycle items cannot directly be overridden') |
| if part['lock']: |
| raise RuntimeError('Life cycle partition cannot be locked') |
| |
| if part['count'] == 0 and part['state'] != "RAW": |
| raise RuntimeError( |
| 'Life cycle transition counter can only be zero in the RAW state' |
| ) |
| |
| # Augment life cycle partition with correct life cycle encoding |
| state = self.lc_state.encode('lc_state', str(part['state'])) |
| count = self.lc_state.encode('lc_cnt', str(part['count'])) |
| part['items'] = [{ |
| 'name': 'LC_STATE', |
| 'value': '0x{:X}'.format(state) |
| }, { |
| 'name': 'LC_TRANSITION_CNT', |
| 'value': '0x{:X}'.format(count) |
| }] |
| |
| # Key accounting |
| part_check = part.copy() |
| del part_check['state'] |
| del part_check['count'] |
| else: |
| # Key accounting |
| part_check = part.copy() |
| if len(part['items']) == 0: |
| log.warning("Partition does not contain any items.") |
| |
| # Key accounting |
| del part_check['items'] |
| del part_check['name'] |
| del part_check['lock'] |
| _check_unused_keys(part_check, "in partition {}".format(part['name'])) |
| |
| def merge_item_data(self, part, item): |
| '''This validates and merges the item data into the memory map dict''' |
| item.setdefault('name', 'unknown_name') |
| item.setdefault('value', '0x0') |
| |
| mmap_item = self.get_item(part['name'], item['name']) |
| if mmap_item is None: |
| raise RuntimeError('Item {} does not exist'.format(item['name'])) |
| |
| item_size = mmap_item['size'] |
| random_or_hexvalue(item, 'value', item_size * 8) |
| mmap_item['value'] = item['value'] |
| |
| log.info('> Adding item {} with size {}B and value:'.format( |
| item['name'], item_size)) |
| fmt_str = '{:0' + str(item_size * 2) + 'x}' |
| value_str = fmt_str.format(item['value']) |
| bytes_per_line = 8 |
| j = 0 |
| while value_str: |
| # Print out max 64bit per line |
| line_str = '' |
| for k in range(bytes_per_line): |
| num_chars = min(len(value_str), 2) |
| line_str += value_str[-num_chars:] |
| if k < bytes_per_line - 1: |
| line_str += ' ' |
| value_str = value_str[:len(value_str) - num_chars] |
| log.info(' {:06x}: '.format(j) + line_str) |
| j += bytes_per_line |
| |
| # Key accounting |
| item_check = item.copy() |
| del item_check['name'] |
| del item_check['value'] |
| _check_unused_keys(item_check, 'in item {}'.format(item['name'])) |
| |
| def override_data(self, img_config): |
| '''Override specific partition items''' |
| |
| if 'partitions' not in img_config: |
| raise RuntimeError('Missing partitions key in configuration.') |
| |
| if not isinstance(img_config['partitions'], list): |
| raise RuntimeError('the "partitions" key must contain a list') |
| |
| for part in img_config['partitions']: |
| self.merge_part_data(part) |
| log.info('Overriding values of {} partition.'.format(part['name'])) |
| for item in part['items']: |
| self.merge_item_data(part, item) |
| |
| # Key accounting |
| img_config_check = img_config.copy() |
| del img_config_check['seed'] |
| del img_config_check['partitions'] |
| _check_unused_keys(img_config_check, 'in image config') |
| |
| def streamout_partition(self, part): |
| '''Scramble and stream out partition data as a list of bytes''' |
| |
| part_name = part['name'] |
| log.info('Streamout of partition {}'.format(part_name)) |
| |
| part_offset = part['offset'] |
| part_size = part['size'] |
| assert part_size % 8 == 0, 'Partition must be 64bit aligned' |
| |
| # First chop up all items into individual bytes. |
| data_bytes = [0] * part_size |
| # Annotation is propagated into the hexfile as comments |
| annotation = ['unallocated'] * part_size |
| # Need to keep track of defined items for the scrambling. |
| # Undefined regions are left blank (0x0) in the memory. |
| defined = [False] * part_size |
| for item in part['items']: |
| for k in range(item['size']): |
| idx = item['offset'] - part_offset + k |
| annotation[idx] = part_name + ': ' + item['name'] |
| if 'value' in item: |
| data_bytes[idx] = ((item['value'] >> (8 * k)) & 0xFF) |
| assert not defined[idx], "Unexpected item collision" |
| defined[idx] = True |
| |
| # Reshape this into 64bit blocks (this must be aligned at this point) |
| assert len(data_bytes) % 8 == 0, 'data_bytes must be 64bit aligned' |
| |
| data_blocks = [] |
| data_block_defined = [] |
| for k, b in enumerate(data_bytes): |
| if (k % 8) == 0: |
| data_blocks.append(b) |
| data_block_defined.append(defined[k]) |
| else: |
| data_blocks[k // 8] += (b << 8 * (k % 8)) |
| # If any of the individual bytes are defined, the |
| # whole block is considered defined. |
| data_block_defined[k // 8] |= defined[k] |
| |
| # Check if scrambling is needed |
| if part['secret']: |
| part_name = part['name'] |
| key_sel = part['key_sel'] |
| log.info('> Scramble partition with key "{}"'.format(key_sel)) |
| |
| for key in self.config['scrambling']['keys']: |
| if key['name'] == key_sel: |
| break |
| else: |
| raise RuntimeError( |
| 'Scrambling key cannot be found {}'.format(key_sel)) |
| |
| for k in range(len(data_blocks)): |
| if data_block_defined[k]: |
| data_blocks[k] = _present_64bit_encrypt( |
| data_blocks[k], key['value']) |
| |
| # Check if digest calculation is needed |
| if part['hw_digest']: |
| # Make sure that this HW-governed digest has not been |
| # overridden manually |
| if data_blocks[-1] != 0: |
| raise RuntimeError( |
| 'Digest of partition {} cannot be overridden manually' |
| .format(part_name)) |
| |
| # Digest is stored in last block of a partition |
| if part.setdefault('lock', False): |
| log.info('> Lock partition by computing digest') |
| # Digest constants at index 0 are used to compute the |
| # consistency digest |
| iv = self.config['scrambling']['digests'][0]['iv_value'] |
| const = self.config['scrambling']['digests'][0]['cnst_value'] |
| |
| data_blocks[-1] = _present_64bit_digest( |
| data_blocks[0:-1], iv, const) |
| else: |
| log.info('> Partition is not locked, hence no digest is computed') |
| |
| # Convert to a list of bytes to make final packing into |
| # OTP memory words independent of the cipher block size. |
| data = [] |
| for block in data_blocks: |
| for k in range(8): |
| data.append((block >> (8 * k)) & 0xFF) |
| |
| # Make sure this has the right size |
| assert len(data) == part['size'], 'Partition size mismatch' |
| |
| # The annotation list contains a string for each byte |
| # that can be used to print out informative comments |
| # in the memory hex file. |
| return data, annotation |
| |
| def streamout_hexfile(self): |
| '''Streamout of memory image in hex file format''' |
| |
| log.info('Scramble and stream out partitions.') |
| log.info('') |
| otp_size = self.config['otp']['size'] |
| data = [0] * otp_size |
| annotation = [''] * otp_size |
| for part in self.config['partitions']: |
| part_data, part_annotation = self.streamout_partition(part) |
| assert part['offset'] <= otp_size, \ |
| 'Partition offset out of bounds' |
| idx_low = part['offset'] |
| idx_high = part['offset'] + part['size'] |
| data[idx_low:idx_high] = part_data |
| annotation[idx_low:idx_high] = part_annotation |
| |
| log.info('') |
| log.info('Streamout successfully completed.') |
| |
| # Smoke checks |
| assert len(data) <= otp_size, 'Data size mismatch' |
| assert len(annotation) <= otp_size, 'Annotation size mismatch' |
| assert len(data) == len(annotation), 'Data/Annotation size mismatch' |
| |
| return _to_hexfile_with_ecc(data, annotation, self.lc_state.config) |
