chore(core): Make CoinJoin checks more lenient.

[no changelog]

core/src/apps/bitcoin/sign_tx/approvers.py

@@ -319,7 +319,9 @@ class BasicApprover(Approver):
 
 
 class CoinJoinApprover(Approver):
-    MAX_OUTPUT_WEIGHT = const(4 * 43)
+    # Maximum weight of an output for standard scriptPubKeys P2PKH (25), P2SH (23), P2WPKH (22),
+    # P2WSH (34) and P2TR (34).
+    MAX_OUTPUT_WEIGHT = const(4 * (8 + 1 + 34))
 
     def __init__(
         self, tx: SignTx, coin: CoinInfo, authorization: CoinJoinAuthorization
@@ -345,9 +347,6 @@ class CoinJoinApprover(Approver):
         # amount of each output in the current group
         self.group_amount = 0
 
-        # flag indicating whether our outputs are gaining any anonymity
-        self.anonymity = False
-
     async def add_internal_input(self, txi: TxInput) -> None:
         self.our_weight.add_input(txi)
         if not self.authorization.check_sign_tx_input(txi, self.coin):
@@ -420,14 +419,6 @@ class CoinJoinApprover(Approver):
         if our_fees > our_coordinator_fee + our_max_mining_fee:
             raise wire.ProcessError("Total fee over threshold")
 
-        # Ensure that at least one of the user's outputs is in a group with an external output.
-        # Note: _get_coordinator_fee() needs to be called before checking this.
-        if not self.anonymity:
-            raise wire.ProcessError("No anonymity gain")
-
-        if tx_info.tx.lock_time > 0:
-            raise wire.ProcessError("nLockTime not allowed in CoinJoin")
-
         if not self.authorization.approve_sign_tx(tx_info.tx, our_fees):
             raise wire.ProcessError("Fees exceed authorized limit")
 

tests/device_tests/bitcoin/test_authorize_coinjoin.py

@@ -345,123 +345,6 @@ def test_unfair_fee(client: Client):
         )
 
 
-def test_no_anonymity(client: Client):
-    # Test CoinJoin transaction giving the user's outputs no gain in anonymity.
-
-    with client:
-        btc.authorize_coinjoin(
-            client,
-            coordinator="www.example.com",
-            max_total_fee=5_005,
-            fee_per_anonymity=5_000_000,  # 0.005 %
-            n=parse_path("m/84h/1h/0h"),
-            coin_name="Testnet",
-            script_type=messages.InputScriptType.SPENDWITNESS,
-        )
-
-    inputs = [
-        messages.TxInputType(
-            # seed "alcohol woman abuse must during monitor noble actual mixed trade anger aisle"
-            # 84'/1'/0'/0/0
-            # tb1qnspxpr2xj9s2jt6qlhuvdnxw6q55jvygcf89r2
-            amount=100_000,
-            prev_hash=TXHASH_e5b7e2,
-            prev_index=0,
-            script_type=messages.InputScriptType.EXTERNAL,
-            script_pubkey=bytes.fromhex("00149c02608d469160a92f40fdf8c6ccced029493088"),
-            ownership_proof=bytearray.fromhex(
-                "534c001901016b2055d8190244b2ed2d46513c40658a574d3bc2deb6969c0535bb818b44d2c40002483045022100a6c7d59b453efa7b4abc9bc724a94c5655ae986d5924dc29d28bcc2b859cbace022047d2bc4422a47f7b044bd6cdfbf63fe1a0ecbf11393f4c0bf8565f867a5ced16012103505f0d82bbdd251511591b34f36ad5eea37d3220c2b81a1189084431ddb3aa3d"
-            ),
-            commitment_data=b"\x0fwww.example.com" + (1).to_bytes(ROUND_ID_LEN, "big"),
-        ),
-        messages.TxInputType(
-            address_n=parse_path("m/84h/1h/0h/1/0"),
-            amount=7_289_000,
-            prev_hash=FAKE_TXHASH_f982c0,
-            prev_index=1,
-            script_type=messages.InputScriptType.SPENDWITNESS,
-        ),
-    ]
-
-    outputs = [
-        # Other's coinjoined output.
-        messages.TxOutputType(
-            address="tb1qk7j3ahs2v6hrv4v282cf0tvxh0vqq7rpt3zcml",
-            amount=30_000,
-            script_type=messages.OutputScriptType.PAYTOWITNESS,
-            payment_req_index=0,
-        ),
-        # Other's coinjoined output.
-        messages.TxOutputType(
-            address="tb1q9cqhdr9ydetjzrct6tyeuccws9505hl96azwxk",
-            amount=30_000,
-            script_type=messages.OutputScriptType.PAYTOWITNESS,
-            payment_req_index=0,
-        ),
-        # Our coinjoined output.
-        messages.TxOutputType(
-            # tb1qze76uzqteg6un6jfcryrxhwvfvjj58ts0swg3d
-            address_n=parse_path("m/84h/1h/0h/1/1"),
-            amount=50_000,
-            script_type=messages.OutputScriptType.PAYTOWITNESS,
-            payment_req_index=0,
-        ),
-        # Our coinjoined output.
-        messages.TxOutputType(
-            # tb1qr5p6f5sk09sms57ket074vywfymuthlgud7xyx
-            address_n=parse_path("m/84h/1h/0h/1/2"),
-            amount=50_000,
-            script_type=messages.OutputScriptType.PAYTOWITNESS,
-            payment_req_index=0,
-        ),
-        # Our change output.
-        messages.TxOutputType(
-            # tb1qwn0s88t9r39g72m78mcaxj72sy3ct4m404xsmq
-            address_n=parse_path("m/84h/1h/0h/1/3"),
-            amount=7_289_000 - 50_000 - 50_000 - 10 - 5_000,
-            script_type=messages.OutputScriptType.PAYTOWITNESS,
-            payment_req_index=0,
-        ),
-        # Other's change output.
-        messages.TxOutputType(
-            address="tb1q9cqhdr9ydetjzrct6tyeuccws9505hl96azwxk",
-            amount=100_000 - 30_000 - 30_000 - 6 - 5_000,
-            script_type=messages.OutputScriptType.PAYTOWITNESS,
-            payment_req_index=0,
-        ),
-        # Coordinator's output.
-        messages.TxOutputType(
-            address="mvbu1Gdy8SUjTenqerxUaZyYjmveZvt33q",
-            amount=16,
-            script_type=messages.OutputScriptType.PAYTOWITNESS,
-            payment_req_index=0,
-        ),
-    ]
-
-    payment_req = make_payment_request(
-        client,
-        recipient_name="www.example.com",
-        outputs=outputs,
-        change_addresses=[
-            "tb1qze76uzqteg6un6jfcryrxhwvfvjj58ts0swg3d",
-            "tb1qr5p6f5sk09sms57ket074vywfymuthlgud7xyx",
-            "tb1qwn0s88t9r39g72m78mcaxj72sy3ct4m404xsmq",
-        ],
-    )
-    payment_req.amount = None
-
-    with pytest.raises(TrezorFailure, match="No anonymity gain"):
-        btc.sign_tx(
-            client,
-            "Testnet",
-            inputs,
-            outputs,
-            prev_txes=TX_CACHE_TESTNET,
-            payment_reqs=[payment_req],
-            preauthorized=True,
-        )
-
-
 def test_wrong_coordinator(client: Client):
     # Ensure that a preauthorized GetOwnershipProof fails if the commitment_data doesn't match the coordinator.
 

tests/ui_tests/fixtures.json

@@ -602,7 +602,6 @@
 "TT_binance-test_sign_tx.py::test_binance_sign_message[message2-expected_response2]": "323e0a474e71ede187ee1332e42952aeca501b42da95f88b2bad5445a3db858c",
 "TT_bitcoin-test_authorize_coinjoin.py::test_cancel_authorization": "9887e0f4da5c7800f832396e50391beb03229c8edcb5b0e078433703cac6e0d3",
 "TT_bitcoin-test_authorize_coinjoin.py::test_multisession_authorization": "fd412d086cf4ff677f6ae266e88de725549505d9a2abc1c2ba36f8f854461694",
-"TT_bitcoin-test_authorize_coinjoin.py::test_no_anonymity": "f0c8167a4a6aa05751c3eab3d8d944044acec497ca0bf05d2e2fc1577a36c5c4",
 "TT_bitcoin-test_authorize_coinjoin.py::test_sign_tx": "c48bbbaf032eacb42567e49f5b4b82ed51fe97bb613e165dca2c51207199f236",
 "TT_bitcoin-test_authorize_coinjoin.py::test_unfair_fee": "ab1aa516510b627b8ffc65391c1c113922ab08f48baf295861a9b597f27f8ea1",
 "TT_bitcoin-test_authorize_coinjoin.py::test_wrong_coordinator": "9887e0f4da5c7800f832396e50391beb03229c8edcb5b0e078433703cac6e0d3",