refactor(python/stellar): Use Stellar Python SDK to parse Stellar transactions.

As a side effect, support for TransactionV1 format transaction is added.

python/.changelog.d/1745.added

@@ -0,0 +1 @@
+`trezorlib.stellar.from_envelope` was added, it includes support for the Stellar [TransactionV1](https://github.com/stellar/stellar-protocol/blob/master/core/cap-0015.md#xdr) format transaction.

python/.changelog.d/1745.incompatible

@@ -0,0 +1 @@
+`trezorlib.stellar` was reworked to use stellar-sdk instead of providing local implementations

python/README.md

@@ -55,7 +55,14 @@ units) will not be recognized, unless you install HIDAPI support (see below).
   pip3 install trezor[ethereum]
   ```
 
-To install both, use `pip3 install trezor[hidapi,ethereum]`.
+* **Stellar**: To support Stellar signing from command line, additional packages are
+  needed. Install with:
+
+  ```sh
+  pip3 install trezor[stellar]
+  ```
+
+To install all three, use `pip3 install trezor[hidapi,ethereum,stellar]`.
 
 ### Distro packages
 

python/requirements-optional.txt

@@ -2,3 +2,4 @@ hidapi >= 0.7.99.post20
 rlp >= 1.1.0
 web3 >= 4.8
 Pillow
+stellar-sdk>=4.0.0,<5.0.0

python/setup.py

@@ -22,6 +22,7 @@ extras_require = {
     "ethereum": ["rlp>=1.1.0", "web3>=4.8"],
     "qt-widgets": ["PyQt5"],
     "extra": ["Pillow"],
+    "stellar": ["stellar-sdk>=4.0.0,<5.0.0"],
 }
 
 extras_require["full"] = sum(extras_require.values(), [])

python/src/trezorlib/cli/stellar.py

@@ -15,12 +15,21 @@
 # If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
 
 import base64
+import sys
 
 import click
 
 from .. import stellar, tools
 from . import with_client
 
+try:
+    from stellar_sdk import (
+        parse_transaction_envelope_from_xdr,
+        FeeBumpTransactionEnvelope,
+    )
+except ImportError:
+    pass
+
 PATH_HELP = "BIP32 path. Always use hardened paths and the m/44'/148'/ prefix"
 
 
@@ -68,8 +77,20 @@ def sign_transaction(client, b64envelope, address, network_passphrase):
     For testnet transactions, use the following network passphrase:
     'Test SDF Network ; September 2015'
     """
+    if not stellar.HAVE_STELLAR_SDK:
+        click.echo("Stellar requirements not installed.")
+        click.echo("Please run:")
+        click.echo()
+        click.echo("  pip install stellar-sdk")
+        sys.exit(1)
+
+    envelope = parse_transaction_envelope_from_xdr(b64envelope, network_passphrase)
+    if isinstance(envelope, FeeBumpTransactionEnvelope):
+        click.echo("FeeBumpTransactionEnvelope is not supported")
+        sys.exit(1)
+
     address_n = tools.parse_path(address)
-    tx, operations = stellar.parse_transaction_bytes(base64.b64decode(b64envelope))
+    tx, operations = stellar.from_envelope(envelope)
     resp = stellar.sign_tx(client, tx, operations, address_n, network_passphrase)
 
     return base64.b64encode(resp.signature)

python/src/trezorlib/stellar.py

@@ -13,14 +13,45 @@
 #
 # You should have received a copy of the License along with this library.
 # If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
-
-import base64
-import struct
-import xdrlib
+from decimal import Decimal
+from typing import Union
 
 from . import exceptions, messages
 from .tools import expect
 
+try:
+    from stellar_sdk import (
+        AccountMerge,
+        AllowTrust,
+        Asset,
+        BumpSequence,
+        ChangeTrust,
+        CreateAccount,
+        CreatePassiveSellOffer,
+        HashMemo,
+        IdMemo,
+        ManageData,
+        ManageSellOffer,
+        Operation,
+        PathPaymentStrictReceive,
+        Payment,
+        ReturnHashMemo,
+        SetOptions,
+        TextMemo,
+        TransactionEnvelope,
+        TrustLineEntryFlag,
+        Price,
+        Network,
+    )
+    from stellar_sdk.xdr.signer_key_type import SignerKeyType
+
+    HAVE_STELLAR_SDK = True
+    DEFAULT_NETWORK_PASSPHRASE = Network.PUBLIC_NETWORK_PASSPHRASE
+
+except ImportError:
+    HAVE_STELLAR_SDK = False
+    DEFAULT_NETWORK_PASSPHRASE = "Public Global Stellar Network ; September 2015"
+
 # Memo types
 MEMO_TYPE_NONE = 0
 MEMO_TYPE_TEXT = 1
@@ -33,309 +64,191 @@ 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
-
-
 DEFAULT_BIP32_PATH = "m/44h/148h/0h"
 # Stellar's BIP32 differs to Bitcoin's see https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0005.md
-DEFAULT_NETWORK_PASSPHRASE = "Public Global Stellar Network ; September 2015"
 
 
-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).decode()
-
-
-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:
+def from_envelope(envelope: "TransactionEnvelope"):
+    """Parses transaction envelope into a map with the following keys:
     tx - a StellarSignTx describing the transaction header
     operations - an array of protobuf message objects for each operation
     """
+    if not HAVE_STELLAR_SDK:
+        raise RuntimeError("Stellar SDK not available")
     tx = messages.StellarSignTx()
-    unpacker = xdrlib.Unpacker(tx_bytes)
-
-    tx.source_account = _xdr_read_address(unpacker)
-    tx.fee = unpacker.unpack_uint()
-    tx.sequence_number = unpacker.unpack_uhyper()
+    parsed_tx = envelope.transaction
+    tx.source_account = parsed_tx.source.account_id
+    tx.fee = parsed_tx.fee
+    tx.sequence_number = parsed_tx.sequence
 
     # 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)
+    if parsed_tx.time_bounds:
+        tx.timebounds_start = parsed_tx.time_bounds.min_time
+        tx.timebounds_end = parsed_tx.time_bounds.max_time
 
-        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_TEXT:
-        tx.memo_text = unpacker.unpack_string().decode()
-    # 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 _ in range(tx.num_operations):
-        operations.append(_parse_operation_bytes(unpacker))
+    memo = parsed_tx.memo
+    if isinstance(memo, TextMemo):
+        # memo_text is specified as UTF-8 string, but returned as bytes from the XDR parser
+        tx.memo_type = MEMO_TYPE_TEXT
+        tx.memo_text = memo.memo_text.decode("utf-8")
+    elif isinstance(memo, IdMemo):
+        tx.memo_type = MEMO_TYPE_ID
+        tx.memo_id = memo.memo_id
+    elif isinstance(memo, HashMemo):
+        tx.memo_type = MEMO_TYPE_HASH
+        tx.memo_hash = memo.memo_hash
+    elif isinstance(memo, ReturnHashMemo):
+        tx.memo_type = MEMO_TYPE_RETURN
+        tx.memo_hash = memo.memo_return
+    else:
+        tx.memo_type = MEMO_TYPE_NONE
 
+    tx.num_operations = len(parsed_tx.operations)
+    operations = [_read_operation(op) for op in parsed_tx.operations]
     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
+def _read_operation(op: "Operation"):
+    # TODO: Let's add muxed account support later.
+    if op.source:
+        source_account = op.source.account_id
+    else:
         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:
+    if isinstance(op, CreateAccount):
         return messages.StellarCreateAccountOp(
             source_account=source_account,
-            new_account=_xdr_read_address(unpacker),
-            starting_balance=unpacker.unpack_hyper(),
+            new_account=op.destination,
+            starting_balance=_read_amount(op.starting_balance),
         )
-
-    if type == OP_PAYMENT:
+    if isinstance(op, Payment):
         return messages.StellarPaymentOp(
             source_account=source_account,
-            destination_account=_xdr_read_address(unpacker),
-            asset=_xdr_read_asset(unpacker),
-            amount=unpacker.unpack_hyper(),
+            destination_account=op.destination.account_id,
+            asset=_read_asset(op.asset),
+            amount=_read_amount(op.amount),
         )
-
-    if type == OP_PATH_PAYMENT:
-        op = messages.StellarPathPaymentOp(
+    if isinstance(op, PathPaymentStrictReceive):
+        operation = messages.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),
-            destination_amount=unpacker.unpack_hyper(),
-            paths=[],
+            send_asset=_read_asset(op.send_asset),
+            send_max=_read_amount(op.send_max),
+            destination_account=op.destination.account_id,
+            destination_asset=_read_asset(op.dest_asset),
+            destination_amount=_read_amount(op.dest_amount),
+            paths=[_read_asset(asset) for asset in op.path],
         )
-
-        num_paths = unpacker.unpack_uint()
-        for _ in range(num_paths):
-            op.paths.append(_xdr_read_asset(unpacker))
-
-        return op
-
-    if type == OP_MANAGE_OFFER:
+        return operation
+    if isinstance(op, ManageSellOffer):
+        price = _read_price(op.price)
         return messages.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(),
+            selling_asset=_read_asset(op.selling),
+            buying_asset=_read_asset(op.buying),
+            amount=_read_amount(op.amount),
+            price_n=price.n,
+            price_d=price.d,
+            offer_id=op.offer_id,
         )
-
-    if type == OP_CREATE_PASSIVE_OFFER:
+    if isinstance(op, CreatePassiveSellOffer):
+        price = _read_price(op.price)
         return messages.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(),
+            selling_asset=_read_asset(op.selling),
+            buying_asset=_read_asset(op.buying),
+            amount=_read_amount(op.amount),
+            price_n=price.n,
+            price_d=price.d,
         )
-
-    if type == OP_SET_OPTIONS:
-        op = messages.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().decode()
-
-        # 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:
+    if isinstance(op, SetOptions):
+        operation = messages.StellarSetOptionsOp(
+            source_account=source_account,
+            inflation_destination_account=op.inflation_dest,
+            clear_flags=op.clear_flags,
+            set_flags=op.set_flags,
+            master_weight=op.master_weight,
+            low_threshold=op.low_threshold,
+            medium_threshold=op.med_threshold,
+            high_threshold=op.high_threshold,
+            home_domain=op.home_domain,
+        )
+        if op.signer:
+            signer_type = op.signer.signer_key.signer_key.type
+            if signer_type == SignerKeyType.SIGNER_KEY_TYPE_ED25519:
+                signer_key = op.signer.signer_key.signer_key.ed25519.uint256
+            elif signer_type == SignerKeyType.SIGNER_KEY_TYPE_HASH_X:
+                signer_key = op.signer.signer_key.signer_key.hash_x.uint256
+            elif signer_type == SignerKeyType.SIGNER_KEY_TYPE_PRE_AUTH_TX:
+                signer_key = op.signer.signer_key.signer_key.pre_auth_tx.uint256
+            else:
+                raise ValueError("Unsupported signer key type")
+            operation.signer_type = signer_type.value
+            operation.signer_key = signer_key
+            operation.signer_weight = op.signer.weight
+        return operation
+    if isinstance(op, ChangeTrust):
         return messages.StellarChangeTrustOp(
             source_account=source_account,
-            asset=_xdr_read_asset(unpacker),
-            limit=unpacker.unpack_uhyper(),
+            asset=_read_asset(op.asset),
+            limit=_read_amount(op.limit),
         )
-
-    if type == OP_ALLOW_TRUST:
-        op = messages.StellarAllowTrustOp(
+    if isinstance(op, AllowTrust):
+        is_authorized = False
+        if op.authorize is True or TrustLineEntryFlag.AUTHORIZED_FLAG == op.authorize:
+            is_authorized = True
+        asset_type = (
+            ASSET_TYPE_ALPHA4 if len(op.asset_code) <= 4 else ASSET_TYPE_ALPHA12
+        )
+        return messages.StellarAllowTrustOp(
             source_account=source_account,
-            trusted_account=_xdr_read_address(unpacker),
-            asset_type=unpacker.unpack_uint(),
+            trusted_account=op.trustor,
+            asset_type=asset_type,
+            asset_code=op.asset_code,
+            is_authorized=is_authorized,
         )
-
-        if op.asset_type == ASSET_TYPE_ALPHA4:
-            op.asset_code = unpacker.unpack_fstring(4).decode()
-        if op.asset_type == ASSET_TYPE_ALPHA12:
-            op.asset_code = unpacker.unpack_fstring(12).decode()
-
-        op.is_authorized = unpacker.unpack_bool()
-
-        return op
-
-    if type == OP_ACCOUNT_MERGE:
+    if isinstance(op, AccountMerge):
         return messages.StellarAccountMergeOp(
             source_account=source_account,
-            destination_account=_xdr_read_address(unpacker),
+            destination_account=op.destination.account_id,
         )
-
     # Inflation is not implemented since anyone can submit this operation to the network
-
-    if type == OP_MANAGE_DATA:
-        op = messages.StellarManageDataOp(
-            source_account=source_account, key=unpacker.unpack_string().decode()
+    if isinstance(op, ManageData):
+        return messages.StellarManageDataOp(
+            source_account=source_account,
+            key=op.data_name,
+            value=op.data_value,
         )
-
-        # 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:
+    if isinstance(op, BumpSequence):
         return messages.StellarBumpSequenceOp(
-            source_account=source_account, bump_to=unpacker.unpack_uhyper()
+            source_account=source_account, bump_to=op.bump_to
         )
-
-    raise ValueError("Unknown operation type: " + str(type))
+    raise ValueError(f"Unknown operation type: {op.__class__.__name__}")
 
 
-def _xdr_read_asset(unpacker):
+def _read_amount(amount: str) -> int:
+    return Operation.to_xdr_amount(amount)
+
+
+def _read_price(price: Union["Price", str, Decimal]) -> "Price":
+    # In the coming stellar-sdk 5.x, the type of price must be Price,
+    # at that time we can remove this function
+    if isinstance(price, Price):
+        return price
+    return Price.from_raw_price(price)
+
+
+def _read_asset(asset: "Asset") -> messages.StellarAssetType:
     """Reads a stellar Asset from unpacker"""
-    asset = messages.StellarAssetType(type=unpacker.unpack_uint())
-
-    if asset.type == ASSET_TYPE_ALPHA4:
-        asset.code = unpacker.unpack_fstring(4).decode()
-        asset.issuer = _xdr_read_address(unpacker)
-
-    if asset.type == ASSET_TYPE_ALPHA12:
-        asset.code = unpacker.unpack_fstring(12).decode()
-        asset.issuer = _xdr_read_address(unpacker)
-
-    return asset
-
-
-def _xdr_read_address(unpacker):
-    """Reads a stellar address and returns the string representing the address
-    This method assumes the encoded address is a public address (starting with G)
-    """
-    # First 4 bytes are the address type
-    address_type = unpacker.unpack_uint()
-    if address_type != 0:
-        raise ValueError("Unsupported address type")
-
-    return address_from_public_key(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
+    if asset.is_native():
+        return messages.StellarAssetType(type=ASSET_TYPE_NATIVE)
+    if asset.guess_asset_type() == "credit_alphanum4":
+        return messages.StellarAssetType(
+            type=ASSET_TYPE_ALPHA4, code=asset.code, issuer=asset.issuer
+        )
+    if asset.guess_asset_type() == "credit_alphanum12":
+        return messages.StellarAssetType(
+            type=ASSET_TYPE_ALPHA12, code=asset.code, issuer=asset.issuer
+        )
+    raise ValueError("Unsupported asset type")
 
 
 # ====== Client functions ====== #

python/tox.ini

@@ -8,6 +8,7 @@ envlist =
 [testenv]
 deps =
     -rrequirements.txt
+    -rrequirements-optional.txt
     pytest>=3.6
     pytest-random-order
     importlib-metadata!=0.21