Merge pull request #546 from LedgerHQ/fix/apa/client_ecrecover

Fix client ecrecover

client/CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.3.1] - 2024-03-12
+
+### Fixed
+
+- `recover_transaction` & `recover_message` util functions
+
 ## [0.3.0] - 2024-02-13
 
 ### Added

client/src/ledger_app_clients/ethereum/utils.py

@@ -3,6 +3,14 @@ from eth_account.messages import encode_defunct, encode_typed_data
 import rlp
 
 
+# eth_account requires it for some reason
+def normalize_vrs(vrs: tuple) -> tuple:
+    vrs_l = list()
+    for elem in vrs:
+        vrs_l.append(elem.lstrip(b'\x00'))
+    return tuple(vrs_l)
+
+
 def get_selector_from_data(data: str) -> bytes:
     raw_data = bytes.fromhex(data[2:])
     return raw_data[:4]
@@ -13,7 +21,7 @@ def recover_message(msg, vrs: tuple) -> bytes:
         smsg = encode_typed_data(full_message=msg)
     else:  # EIP-191
         smsg = encode_defunct(primitive=msg)
-    addr = Account.recover_message(smsg, vrs)
+    addr = Account.recover_message(smsg, normalize_vrs(vrs))
     return bytes.fromhex(addr[2:])
 
 
@@ -23,17 +31,33 @@ def recover_transaction(tx_params, vrs: tuple) -> bytes:
     if raw_tx[0] in [0x01, 0x02]:
         prefix = raw_tx[:1]
         raw_tx = raw_tx[len(prefix):]
-    # v is returned on one byte only so it might have overflowed
-    # in that case, we will reconstruct it to its full value
-    if "chainId" in tx_params:
-        trunc_chain_id = tx_params["chainId"]
-        while trunc_chain_id.bit_length() > 32:
-            trunc_chain_id >>= 8
-        target = tx_params["chainId"] * 2 + 35
-        trunc_target = trunc_chain_id * 2 + 35
-        diff = vrs[0][0] - (trunc_target & 0xff)
-        vrs = (target + diff, vrs[1], vrs[2])
+    else:
+        if "chainId" in tx_params:
+            # v is returned on one byte only so it might have overflowed
+            # in that case, we will reconstruct it to its full value
+            trunc_chain_id = tx_params["chainId"]
+            while trunc_chain_id.bit_length() > 32:
+                trunc_chain_id >>= 8
+
+            trunc_target = trunc_chain_id * 2 + 35
+            trunc_v = int.from_bytes(vrs[0], "big")
+
+            if (trunc_target & 0xff) == trunc_v:
+                parity = 0
+            elif ((trunc_target + 1) & 0xff) == trunc_v:
+                parity = 1
+            else:
+                # should have matched with a previous if
+                assert False
+
+            # https://github.com/ethereum/EIPs/blob/master/EIPS/eip-155.md
+            full_v = parity + tx_params["chainId"] * 2 + 35
+            # 9 bytes would be big enough even for the biggest chain ID
+            vrs = (int(full_v).to_bytes(9, "big"), vrs[1], vrs[2])
+        else:
+            # Pre EIP-155 TX
+            assert False
     decoded = rlp.decode(raw_tx)
-    reencoded = rlp.encode(decoded[:-3] + list(vrs))
+    reencoded = rlp.encode(decoded[:-3] + list(normalize_vrs(vrs)))
     addr = Account.recover_transaction(prefix + reencoded)
     return bytes.fromhex(addr[2:])