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WIP - change_language.py

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pull/3491/head
matejcik 5 months ago
parent 21d3a7fff9
commit ee695a9a2c
1 changed files with 25 additions and 162 deletions
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187
core/src/apps/management/change_language.py
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@ -1,157 +1,12 @@
from micropython import const
from typing import TYPE_CHECKING
from trezor.crypto.hashlib import sha256
from trezor.wire import DataError
if TYPE_CHECKING:
from trezor.messages import ChangeLanguage, Success
_CHUNK_SIZE = const(1024)
_HEADER_SIZE = const(256)
_FILL_BYTE = b"\x00"
THRESHOLD = 2
PUBLIC_KEYS = (
b"\x43\x34\x99\x63\x43\x62\x3e\x46\x2f\x0f\xc9\x33\x11\xfe\xf1\x48\x4c\xa2\x3d\x2f\xf1\xee\xc6\xdf\x1f\xa8\xeb\x7e\x35\x73\xb3\xdb",
b"\xa9\xa2\x2c\xc2\x65\xa0\xcb\x1d\x6c\xb3\x29\xbc\x0e\x60\xbc\x45\xdf\x76\xb9\xab\x28\xfb\x87\xb6\x11\x36\xfe\xaf\x8d\x8f\xdc\x96",
b"\xb8\xd2\xb2\x1d\xe2\x71\x24\xf0\x51\x1f\x90\x3a\xe7\xe6\x0e\x07\x96\x18\x10\xa0\xb8\xf2\x8e\xa7\x55\xfa\x50\x36\x7a\x8a\x2b\x8b",
)
if __debug__:
DEV_PUBLIC_KEYS = (
b"\x68\x46\x0e\xbe\xf3\xb1\x38\x16\x4e\xc7\xfd\x86\x10\xe9\x58\x00\xdf\x75\x98\xf7\x0f\x2f\x2e\xa7\xdb\x51\x72\xac\x74\xeb\xc1\x44",
b"\x8d\x4a\xbe\x07\x4f\xef\x92\x29\xd3\xb4\x41\xdf\xea\x4f\x98\xf8\x05\xb1\xa2\xb3\xa0\x6a\xe6\x45\x81\x0e\xfe\xce\x77\xfd\x50\x44",
b"\x97\xf7\x13\x5a\x9a\x26\x90\xe7\x3b\xeb\x26\x55\x6f\x1c\xb1\x63\xbe\xa2\x53\x2a\xff\xa1\xe7\x78\x24\x30\xbe\x98\xc0\xe5\x68\x12",
)
class TranslationsHeader:
MAGIC = b"TRTR"
VERSION_LEN = 16
LANG_LEN = 32
DATA_HASH_LEN = 32
CHANGE_LANGUAGE_TITLE_LEN = 20
CHANGE_LANGUAGE_PROMPT_LEN = 40
SIGNATURE_LEN = 64 + 1
def __init__(
self,
raw_data: bytes,
version: str,
language: str,
data_length: int,
translations_length: int,
translations_num: int,
data_hash: bytes,
change_language_title: str,
change_language_prompt: str,
sigmask: int,
signature: bytes,
):
self.raw_data = raw_data
self.version = version
self.language = language
self.data_length = data_length
self.translations_length = translations_length
self.translations_num = translations_num
self.data_hash = data_hash
self.change_language_title = change_language_title
self.change_language_prompt = change_language_prompt
self.sigmask = sigmask
self.signature = signature
@classmethod
def from_bytes(cls, data: bytes) -> "TranslationsHeader":
from trezor.utils import BufferReader
from apps.common import readers
if len(data) != _HEADER_SIZE:
raise DataError("Invalid header length")
try:
r = BufferReader(data)
magic = r.read(len(cls.MAGIC))
if magic != cls.MAGIC:
raise DataError("Invalid header magic")
version = r.read(cls.VERSION_LEN).rstrip(_FILL_BYTE).decode()
language = r.read(cls.LANG_LEN).rstrip(_FILL_BYTE).decode()
data_length = readers.read_uint16_le(r)
translations_length = readers.read_uint16_le(r)
translations_num = readers.read_uint16_le(r)
data_hash = r.read(cls.DATA_HASH_LEN)
change_language_title = (
r.read(cls.CHANGE_LANGUAGE_TITLE_LEN).rstrip(_FILL_BYTE).decode()
)
change_language_prompt = (
r.read(cls.CHANGE_LANGUAGE_PROMPT_LEN).rstrip(_FILL_BYTE).decode()
)
# Signature occupies last 65 bytes (sigmask + signature itself)
rest = r.read()
if len(rest) < cls.SIGNATURE_LEN:
raise DataError("Invalid header data")
zeros = rest[: -cls.SIGNATURE_LEN]
signature_part = rest[-cls.SIGNATURE_LEN :]
sigmask = signature_part[0]
signature = signature_part[1:]
# Rest must be empty bytes
for b in zeros:
if b != 0:
raise DataError("Invalid header data")
return cls(
raw_data=data,
language=language,
version=version,
data_length=data_length,
translations_length=translations_length,
translations_num=translations_num,
data_hash=data_hash,
change_language_title=change_language_title,
change_language_prompt=change_language_prompt,
sigmask=sigmask,
signature=signature,
)
except EOFError:
raise DataError("Invalid header data")
def version_tuple(self) -> tuple[int, int, int]:
try:
version_parts = self.version.split(".")
major = int(version_parts[0])
minor = int(version_parts[1])
patch = int(version_parts[2])
return major, minor, patch
except (ValueError, IndexError):
raise DataError("Invalid header version")
def check_signature(self) -> bool:
from trezor.crypto.cosi import verify as cosi_verify
# Nullifying the signature data themselves
value_to_hash = (
self.raw_data[: -self.SIGNATURE_LEN] + b"\x00" * self.SIGNATURE_LEN
)
hasher = sha256()
hasher.update(value_to_hash)
hash: bytes = hasher.digest()
sig_result = cosi_verify(
self.signature, hash, THRESHOLD, PUBLIC_KEYS, self.sigmask
)
if __debug__:
debug_sig_result = cosi_verify(
self.signature, hash, THRESHOLD, DEV_PUBLIC_KEYS, self.sigmask
)
sig_result = sig_result or debug_sig_result
return sig_result
async def change_language(msg: ChangeLanguage) -> Success:
@ -166,35 +21,41 @@ async def change_language(msg: ChangeLanguage) -> Success:
await _require_confirm_change_language(
"Change language", "Do you want to change language to English?"
)
translations.wipe()
translations.deinit()
translations.erase()
# translations.init() would be a no-op here
return Success(message="Language reverted to default")
if data_length > translations.data_max_size():
if data_length > translations.area_bytesize():
raise DataError("Translations too long")
if data_length < _HEADER_SIZE:
if data_length < translations.MAX_HEADER_LEN:
raise DataError("Translations too short")
# Getting and parsing the header
header_data = await get_data_chunk(_HEADER_SIZE, 0)
header = TranslationsHeader.from_bytes(header_data[:])
header_data = await get_data_chunk(msg.data_length, 0)
try:
header = translations.TranslationsHeader(header_data)
except ValueError as e:
if e.args:
raise DataError("Invalid header: " + e.args[0]) from None
else:
raise DataError("Invalid header") from None
# Verifying header information
if header.data_length + _HEADER_SIZE != data_length:
if header.total_len != data_length:
raise DataError("Invalid header data length")
# TODO: how to handle the version updates - numbers have to be bumped in cs.json and others
# (or have this logic in a separate blob-creating tool)
# (have some static check in make gen_check?)
if header.version_tuple() != (
if header.version != (
utils.VERSION_MAJOR,
utils.VERSION_MINOR,
utils.VERSION_PATCH,
0,
):
raise DataError("Invalid translations version")
# Verify signature
if not header.check_signature():
raise DataError("Invalid translations signature")
# Confirm with user
await _require_confirm_change_language(
header.change_language_title, header.change_language_prompt
@ -207,7 +68,7 @@ async def change_language(msg: ChangeLanguage) -> Success:
# If we saved it gradually to the storage and only checked the fingerprint at the end
# (with the idea of deleting the data if the fingerprint does not match),
# attackers could still write some data into storage and then unplug the device.
blob = utils.empty_bytearray(translations.data_max_size())
blob = utils.empty_bytearray(translations.area_bytesize())
# Write the header
blob.extend(header_data)
@ -216,20 +77,22 @@ async def change_language(msg: ChangeLanguage) -> Success:
# Also checking the hash of the data for consistency
data_left = data_length - len(header_data)
offset = len(header_data)
hash_writer = utils.HashWriter(sha256())
while data_left > 0:
data_chunk = await get_data_chunk(data_left, offset)
blob.extend(data_chunk)
hash_writer.write(data_chunk)
data_left -= len(data_chunk)
offset += len(data_chunk)
# When the data do not match the hash, do not write anything
if hash_writer.get_digest() != header.data_hash:
raise DataError("Invalid data hash")
try:
translations.verify(blob)
except Exception:
raise DataError("Translation data verification failed.")
translations.wipe()
translations.deinit()
translations.erase()
translations.write(blob, 0)
translations.init()
return Success(message="Language changed")

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