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trezor-firmware/trezorlib/stellar.py
2018-04-28 12:59:08 -06:00

327 lines
9.7 KiB
Python

import base64
import struct
import xdrlib
from . import messages as proto
# Memo types
MEMO_TYPE_TEXT = 0
MEMO_TYPE_ID = 1
MEMO_TYPE_HASH = 2
MEMO_TYPE_RETURN = 4
# Asset types
ASSET_TYPE_NATIVE = 0
ASSET_TYPE_ALPHA4 = 1
ASSET_TYPE_ALPHA12 = 2
# Operations
OP_CREATE_ACCOUNT = 0
OP_PAYMENT = 1
OP_PATH_PAYMENT = 2
OP_MANAGE_OFFER = 3
OP_CREATE_PASSIVE_OFFER = 4
OP_SET_OPTIONS = 5
OP_CHANGE_TRUST = 6
OP_ALLOW_TRUST = 7
OP_ACCOUNT_MERGE = 8
OP_INFLATION = 9 # Included for documentation purposes, not supported by Trezor
OP_MANAGE_DATA = 10
OP_BUMP_SEQUENCE = 11
def expand_path_or_default(client, address):
"""Uses client to parse address and returns an array of integers
If no address is specified, the default of m/44'/148'/0' is used
"""
if address:
return client.expand_path(address)
else:
return client.expand_path("m/44'/148'/0'")
def address_from_public_key(pk_bytes):
"""Returns the base32-encoded version of pk_bytes (G...)
"""
final_bytes = bytearray()
# version
final_bytes.append(6 << 3)
# public key
final_bytes.extend(pk_bytes)
# checksum
final_bytes.extend(struct.pack("<H", _crc16_checksum(final_bytes)))
return base64.b32encode(final_bytes)
def address_to_public_key(address_str):
"""Returns the raw 32 bytes representing a public key by extracting
it from the G... string
"""
decoded = base64.b32decode(address_str)
# skip 0th byte (version) and last two bytes (checksum)
return decoded[1:-2]
def parse_transaction_bytes(tx_bytes):
"""Parses base64data into a map with the following keys:
tx - a StellarSignTx describing the transaction header
operations - an array of protobuf message objects for each operation
"""
tx = proto.StellarSignTx(
protocol_version=1
)
unpacker = xdrlib.Unpacker(tx_bytes)
tx.source_account = _xdr_read_address(unpacker)
tx.fee = unpacker.unpack_uint()
tx.sequence_number = unpacker.unpack_uhyper()
# Timebounds is an optional field
if unpacker.unpack_bool():
max_timebound = 2**32 - 1 # max unsigned 32-bit int (trezor does not support the full 64-bit time value)
tx.timebounds_start = unpacker.unpack_uhyper()
tx.timebounds_end = unpacker.unpack_uhyper()
if tx.timebounds_start > max_timebound or tx.timebounds_start < 0:
raise ValueError("Starting timebound out of range (must be between 0 and " + max_timebound)
if tx.timebounds_end > max_timebound or tx.timebounds_end < 0:
raise ValueError("Ending timebound out of range (must be between 0 and " + max_timebound)
# memo type determines what optional fields are set
tx.memo_type = unpacker.unpack_uint()
# text
if tx.memo_type == MEMO_TYPE_HASH:
tx.memo_text = unpacker.unpack_string()
# id (64-bit uint)
if tx.memo_type == MEMO_TYPE_ID:
tx.memo_id = unpacker.unpack_uhyper()
# hash / return are the same structure (32 bytes representing a hash)
if tx.memo_type == MEMO_TYPE_HASH or tx.memo_type == MEMO_TYPE_RETURN:
tx.memo_hash = unpacker.unpack_fopaque(32)
tx.num_operations = unpacker.unpack_uint()
operations = []
for i in range(tx.num_operations):
operations.append(_parse_operation_bytes(unpacker))
return tx, operations
def _parse_operation_bytes(unpacker):
"""Returns a protobuf message representing the next operation as read from
the byte stream in unpacker
"""
# Check for and parse optional source account field
source_account = None
if unpacker.unpack_bool():
source_account = unpacker.unpack_fopaque(32)
# Operation type (See OP_ constants)
type = unpacker.unpack_uint()
if type == OP_CREATE_ACCOUNT:
return proto.StellarCreateAccountOp(
source_account=source_account,
new_account=_xdr_read_address(unpacker),
starting_balance=unpacker.unpack_hyper()
)
if type == OP_PAYMENT:
return proto.StellarPaymentOp(
source_account=source_account,
destination_account=_xdr_read_address(unpacker),
asset=_xdr_read_asset(unpacker),
amount=unpacker.unpack_hyper()
)
if type == OP_PATH_PAYMENT:
op = proto.StellarPathPaymentOp(
source_account=source_account,
send_asset=_xdr_read_asset(unpacker),
send_max=unpacker.unpack_hyper(),
destination_account=_xdr_read_address(unpacker),
destination_asset=_xdr_read_asset(unpacker),
paths=[]
)
num_paths = unpacker.unpack_uint()
for i in range(num_paths):
op.paths.append(_xdr_read_asset(unpacker))
return op
if type == OP_MANAGE_OFFER:
return proto.StellarManageOfferOp(
source_account=source_account,
selling_asset=_xdr_read_asset(unpacker),
buying_asset=_xdr_read_asset(unpacker),
amount=unpacker.unpack_hyper(),
price_n=unpacker.unpack_uint(),
price_d=unpacker.unpack_uint(),
offer_id=unpacker.unpack_uhyper()
)
if type == OP_CREATE_PASSIVE_OFFER:
return proto.StellarCreatePassiveOfferOp(
source_account=source_account,
selling_asset=_xdr_read_asset(unpacker),
buying_asset=_xdr_read_asset(unpacker),
amount=unpacker.unpack_hyper(),
price_n=unpacker.unpack_uint(),
price_d=unpacker.unpack_uint()
)
if type == OP_SET_OPTIONS:
op = proto.StellarSetOptionsOp(
source_account=source_account
)
# Inflation destination
if unpacker.unpack_bool():
op.inflation_destination_account = _xdr_read_address(unpacker)
# clear flags
if unpacker.unpack_bool():
op.clear_flags = unpacker.unpack_uint()
# set flags
if unpacker.unpack_bool():
op.set_flags = unpacker.unpack_uint()
# master weight
if unpacker.unpack_bool():
op.master_weight = unpacker.unpack_uint()
# low threshold
if unpacker.unpack_bool():
op.low_threshold = unpacker.unpack_uint()
# medium threshold
if unpacker.unpack_bool():
op.medium_threshold = unpacker.unpack_uint()
# high threshold
if unpacker.unpack_bool():
op.high_threshold = unpacker.unpack_uint()
# home domain
if unpacker.unpack_bool():
op.home_domain = unpacker.unpack_string()
# signer
if unpacker.unpack_bool():
op.signer_type = unpacker.unpack_uint()
op.signer_key = unpacker.unpack_fopaque(32)
op.signer_weight = unpacker.unpack_uint()
return op
if type == OP_CHANGE_TRUST:
return proto.StellarChangeTrustOp(
source_account=source_account,
asset=_xdr_read_asset(unpacker),
limit=unpacker.unpack_uhyper()
)
if type == OP_ALLOW_TRUST:
op = proto.StellarAllowTrustOp(
source_account=source_account,
trusted_account=_xdr_read_address(unpacker),
asset_type=unpacker.unpack_uint()
)
if op.asset_type == ASSET_TYPE_ALPHA4:
op.asset_code = unpacker.unpack_fstring(4)
if op.asset_type == ASSET_TYPE_ALPHA12:
op.asset_code = unpacker.unpack_fstring(12)
op.is_authorized = unpacker.unpack_bool()
return op
if type == OP_ACCOUNT_MERGE:
return proto.StellarAccountMergeOp(
source_account=source_account,
destination_account=_xdr_read_address(unpacker)
)
# Inflation is not implemented since anyone can submit this operation to the network
if type == OP_MANAGE_DATA:
op = proto.StellarManageDataOp(
source_account=source_account,
key=unpacker.unpack_string(),
)
# Only set value if the field is present
if unpacker.unpack_bool():
op.value = unpacker.unpack_opaque()
return op
# Bump Sequence
# see: https://github.com/stellar/stellar-core/blob/master/src/xdr/Stellar-transaction.x#L269
if type == OP_BUMP_SEQUENCE:
return proto.StellarBumpSequenceOp(
source_account=source_account,
bump_to=unpacker.unpack_uhyper()
)
raise ValueError("Unknown operation type: " + type)
def _xdr_read_asset(unpacker):
"""Reads a stellar Asset from unpacker"""
asset = proto.StellarAssetType(
type=unpacker.unpack_uint()
)
if asset.type == ASSET_TYPE_ALPHA4:
asset.code = unpacker.unpack_fstring(4)
asset.issuer = _xdr_read_address(unpacker)
if asset.type == ASSET_TYPE_ALPHA12:
asset.code = unpacker.unpack_fstring(12)
asset.issuer = _xdr_read_address(unpacker)
return asset
def _xdr_read_address(unpacker):
"""Reads a stellar address and returns the 32-byte
data representing the address
"""
# First 4 bytes are the address type
address_type = unpacker.unpack_uint()
if address_type != 0:
raise ValueError("Unsupported address type")
return unpacker.unpack_fopaque(32)
def _crc16_checksum(bytes):
"""Returns the CRC-16 checksum of bytearray bytes
Ported from Java implementation at: http://introcs.cs.princeton.edu/java/61data/CRC16CCITT.java.html
Initial value changed to 0x0000 to match Stellar configuration.
"""
crc = 0x0000
polynomial = 0x1021
for byte in bytes:
for i in range(8):
bit = ((byte >> (7 - i) & 1) == 1)
c15 = ((crc >> 15 & 1) == 1)
crc <<= 1
if c15 ^ bit:
crc ^= polynomial
return crc & 0xffff