signing/multisig: segwit support

src/apps/wallet/sign_tx/scripts.py

@@ -1,6 +1,7 @@
 from apps.wallet.sign_tx.writers import *
 
 from trezor.crypto.hashlib import sha256, ripemd160
+from apps.wallet.sign_tx.multisig import multisig_get_pubkeys
 
 # TX Scripts
 # ===
@@ -69,7 +70,7 @@ def output_script_native_p2wpkh_or_p2wsh(witprog: bytes) -> bytearray:
     return w
 
 
-# =============== Native P2WPKH nested in P2SH ===============
+# =============== P2WPKH nested in P2SH ===============
 # P2WPKH is nested in P2SH to be backwards compatible
 # see https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki#witness-program
 
@@ -77,7 +78,7 @@ def output_script_native_p2wpkh_or_p2wsh(witprog: bytes) -> bytearray:
 # signature is moved to the witness
 def input_script_p2wpkh_in_p2sh(pubkeyhash: bytes) -> bytearray:
     w = bytearray_with_cap(3 + len(pubkeyhash))
-    w.append(0x16)  # 0x16 - length of the redeemScript
+    w.append(0x16)  # length of the data
     w.append(0x00)  # witness version byte
     w.append(0x14)  # P2WPKH witness program (pub key hash length)
     write_bytes(w, pubkeyhash)  # pub key hash
@@ -98,7 +99,63 @@ def input_script_p2wpkh_in_p2sh(pubkeyhash: bytes) -> bytearray:
 # output script consists of 00 20 <32-byte-key-hash>
 # same as output_script_native_p2wpkh_or_p2wsh (only different length)
 
-# =============== Multisig ===============
+
+# =============== P2WSH nested in P2SH ===============
+# P2WSH is nested in P2SH to be backwards compatible
+# see https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki#p2wsh-nested-in-bip16-p2sh
+
+# input script (scriptSig) is 22 00 20 <redeem script hash>
+# P2WSH script hash is always equal to 32 bytes (Ox20)
+# signature is moved to the witness
+def input_script_p2wsh_in_p2sh(script_hash: bytes) -> bytearray:
+    if len(script_hash) != 32:
+        raise Exception('Redeem script hash should be 32 bytes long')
+
+    w = bytearray_with_cap(3 + len(script_hash))
+    w.append(0x22)  # length of the data
+    w.append(0x00)  # witness version byte
+    w.append(0x20)  # P2WSH witness program (redeem script hash length)
+    write_bytes(w, script_hash)
+    return w
+
+# output script (scriptPubKey) is A9 14 <scripthash> 87
+# which is same as the output_script_p2sh
+
+
+# =============== SegWit Witness getters ===============
+
+def get_p2wpkh_witness(signature: bytes, pubkey: bytes, sighash: int):
+    w = bytearray_with_cap(1 + 5 + len(signature) + 1 + 5 + len(pubkey))
+    write_varint(w, 0x02)  # num of segwit items, in P2WPKH it's always 2
+    append_signature(w, signature, sighash)
+    append_pubkey(w, pubkey)
+    return w
+
+
+def get_p2wsh_witness(multisig: MultisigRedeemScriptType, current_signature: bytes, other_signatures, sighash: int):
+    # filter empty
+    other_signatures = [s for s in other_signatures if len(s) > 0]
+
+    # witness program + other signatures + current signature + redeem script
+    num_of_witness_items = 1 + len(other_signatures) + 1 + 1
+
+    w = bytearray()
+    write_varint(w, num_of_witness_items)
+    write_varint(w, 0)  # version 0 witness program
+
+    for s in other_signatures:
+        append_signature(w, s, sighash)  # size of the witness included
+
+    append_signature(w, current_signature, sighash)
+
+    redeem_script = script_multisig(multisig_get_pubkeys(multisig), multisig.m)
+
+    write_varint(w, len(redeem_script))
+    write_bytes(w, redeem_script)
+    return w
+
+
+# -------------------------- Multisig --------------------------
 
 def input_script_multisig(current_signature, other_signatures, pubkeys, m: int, sighash: int):
     w = bytearray()
@@ -126,7 +183,7 @@ def output_script_multisig_p2sh(pubkeys, m) -> bytes:
     return ripemd160(h).digest()
 
 
-# returns a sha256() hash of a multisig script used in native P2WSH
+# returns a sha256() hash of a multisig script used in P2WSH
 def output_script_multisig_p2wsh(pubkeys, m) -> bytes:
     for pubkey in pubkeys:
         if len(pubkey) != 33:

src/apps/wallet/sign_tx/segwit_bip143.py

@@ -3,7 +3,8 @@ from trezor.messages.SignTx import SignTx
 from trezor.messages import InputScriptType, FailureType
 
 from apps.wallet.sign_tx.writers import *
-from apps.wallet.sign_tx.scripts import output_script_p2pkh
+from apps.wallet.sign_tx.scripts import output_script_p2pkh, script_multisig
+from apps.wallet.sign_tx.multisig import multisig_get_pubkeys
 from apps.common.hash_writer import HashWriter
 
 
@@ -62,9 +63,9 @@ class Bip143:
     # see https://github.com/bitcoin/bips/blob/master/bip-0143.mediawiki#specification
     # item 5 for details
     def derive_script_code(self, txi: TxInputType, pubkeyhash: bytes) -> bytearray:
-        # p2wsh multisig to be implemented
+
         if txi.multisig:
-            raise Bip143Error(FailureType.DataError, 'Bip143 multisig support to be implemented')
+            return script_multisig(multisig_get_pubkeys(txi.multisig), txi.multisig.m)
 
         p2pkh = (txi.script_type == InputScriptType.SPENDWITNESS or
                  txi.script_type == InputScriptType.SPENDP2SHWITNESS or

src/apps/wallet/sign_tx/signing.py

@@ -103,7 +103,7 @@ async def check_tx_fee(tx: SignTx, root):
             segwit[i] = False
             total_in += await get_prevtx_output_value(
                 tx_req, txi.prev_hash, txi.prev_index)
-            if txi.script_type == InputScriptType.SPENDMULTISIG:
+            if txi.multisig:
                 fp = multisig_fingerprint(txi.multisig)
                 if not len(multisig_fp):
                     multisig_fp = fp
@@ -345,7 +345,10 @@ async def sign_tx(tx: SignTx, root):
                 tx, txi, ecdsa_hash_pubkey(key_sign_pub), get_hash_type(coin))
 
             signature = ecdsa_sign(key_sign, bip143_hash)
-            witness = get_p2wpkh_witness(coin, signature, key_sign_pub)
+            if txi.multisig:
+                witness = get_p2wsh_witness(txi.multisig, signature, txi.multisig.signatures, get_hash_type(coin))
+            else:
+                witness = get_p2wpkh_witness(signature, key_sign_pub, get_hash_type(coin))
 
             tx_ser.serialized_tx = witness
             tx_ser.signature_index = i
@@ -426,14 +429,6 @@ def get_tx_header(tx: SignTx, segwit=False):
     return w_txi
 
 
-def get_p2wpkh_witness(coin: CoinType, signature: bytes, pubkey: bytes):
-    w = bytearray_with_cap(1 + 5 + len(signature) + 1 + 5 + len(pubkey))
-    write_varint(w, 0x02)  # num of segwit items, in P2WPKH it's always 2
-    append_signature(w, signature, get_hash_type(coin))
-    append_pubkey(w, pubkey)
-    return w
-
-
 # TX Outputs
 # ===
 
@@ -506,10 +501,17 @@ def output_is_change(o: TxOutputType, wallet_path: list, segwit_in: int) -> bool
 def input_derive_script(coin: CoinType, i: TxInputType, pubkey: bytes, signature: bytes=None) -> bytes:
     if i.script_type == InputScriptType.SPENDADDRESS:
         return input_script_p2pkh_or_p2sh(pubkey, signature, get_hash_type(coin))  # p2pkh or p2sh
-    if i.script_type == InputScriptType.SPENDP2SHWITNESS:  # p2wpkh using p2sh
+
+    if i.script_type == InputScriptType.SPENDP2SHWITNESS:  # p2wpkh or p2wsh using p2sh
+        if i.multisig:  # p2wsh in p2sh
+            return input_script_p2wsh_in_p2sh(output_script_multisig_p2wsh(multisig_get_pubkeys(i.multisig),
+                                                                           i.multisig.m))
+        # p2wpkh in p2sh
         return input_script_p2wpkh_in_p2sh(ecdsa_hash_pubkey(pubkey))
+
     elif i.script_type == InputScriptType.SPENDWITNESS:  # native p2wpkh or p2wsh
         return input_script_native_p2wpkh_or_p2wsh()
+
     # mutlisig
     elif i.script_type == InputScriptType.SPENDMULTISIG:
         return input_script_multisig(signature, i.multisig.signatures, multisig_get_pubkeys(i.multisig), i.multisig.m,