refactor(core): simplify ETH access list RLP encoding
What the developer wrote
Authored by Roman Zeyde
refactor(core): simplify ETH access list RLP encoding
`rlp.length()` and `rlp.write()` support handling a list of `RLPItem`s.
https://eips.ethereum.org/EIPS/eip-2930#parameters
[no changelog]
What changed, and why it matters
This commit is a small internal cleanup of how Ethereum transaction 'access lists' are formatted for RLP encoding in the Trezor firmware. It replaces a hand-rolled length calculation and manual header writing with higher-level helper functions that do the same job. There is no user-visible behavior change and no indication of a security fix.
No security action required. Treat as a normal code-quality refactor.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The change refactors core/src/apps/ethereum/sign_tx_eip1559.py so that an access list item is produced as an rlp.RLPItem list ([address_bytes, storage_keys]) and then passed to rlp.length() and rlp.write(). Previously the code computed the RLP header length manually and wrote the address and storage keys separately. The streaming SHA digest update path and the length-estimation path both use the same new helper. The commit message calls this a ‘refactor’ and explicitly notes ‘[no changelog]’.
Changed components
core/src/apps/ethereum/sign_tx_eip1559.pyInspect captured patch +6 / −16
### core/src/apps/ethereum/sign_tx_eip1559.py
@@ -21,12 +21,8 @@
_TX_TYPE = const(2)
-def access_list_item_length(item: EthereumAccessList) -> int:
- address_length = rlp.length(bytes_from_address(item.address))
- keys_length = rlp.length(item.storage_keys)
- return (
- rlp.header_length(address_length + keys_length) + address_length + keys_length
- )
+def access_list_item(item: EthereumAccessList) -> rlp.RLPItem:
+ return [bytes_from_address(item.address), item.storage_keys]
@with_keychain_from_chain_id
@@ -117,16 +113,11 @@ async def sign_tx_eip1559(
create_data_chunk_loader(sha),
)
- # write_access_list
- payload_length = sum(access_list_item_length(i) for i in msg.access_list)
+ # write_access_list (streaming instead of full materialization)
+ payload_length = sum(rlp.length(access_list_item(i)) for i in msg.access_list)
rlp.write_header(sha, payload_length, rlp.LIST_HEADER_BYTE)
for item in msg.access_list:
- address_bytes = bytes_from_address(item.address)
- address_length = rlp.length(address_bytes)
- keys_length = rlp.length(item.storage_keys)
- rlp.write_header(sha, address_length + keys_length, rlp.LIST_HEADER_BYTE)
- rlp.write(sha, address_bytes)
- rlp.write(sha, item.storage_keys)
+ rlp.write(sha, access_list_item(item))
digest = sha.get_digest()
@@ -156,9 +147,8 @@ def _get_digest_length(msg: EthereumSignTxEIP1559, data_length: int) -> int:
length += data_length
# access_list_length
- payload_length = sum(access_list_item_length(i) for i in msg.access_list)
+ payload_length = sum(rlp.length(access_list_item(i)) for i in msg.access_list)
access_list_length = rlp.header_length(payload_length) + payload_length
-
length += access_list_length
return lengthWhy this scored 12/100
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