Protocol Feature: Disallow extra data in packed_transaction and eliminate compression from transaction receipt commitments

[heifner]

See https://github.com/AntelopeIO/spring/blob/main/unittests/misc_tests.cpp#L837-L837
Add a protocol feature (or add to one already being added) to disallow extra data beyond the packed transaction in packed_transaction. Also, eliminate compression from transaction receipt commitments, while still allowing for compression for data at rest or in transit.

[heifner]

Proposal: packed_transaction enhancement

No extra data and no on-disk compression

Introduction

This proposal outlines two key modifications to packed_transaction

1. Disallowing the inclusion of extra, unspecified data within packed_transaction.
2. Removing support for compression that is persistently stored on the blockchain, while maintaining support for "on-the-wire" compression during network transmission.

Extra Data in packed_transaction

Currently, the packed_transaction serialization mechanism permits the inclusion of data that are not explicitly defined or expected as part of a valid transaction.

Blockchain-Stored Compression

Currently, packed_transaction maintains the original compression for the lifetime of the transaction. It is transmitted and stored with its initial compression or lack of compression.

Proposed Solution

• Modify packed_transaction in chain_plugin API requests send/push_transaction support to reject packed_transaction that have any extra data after defined struct.
• Continue to support packed_transaction in chain_plugin API requests send/push_transaction support of compressed or uncompressed packed_transaction.
• Modify packed_transaction zip bomb protection from hard-coded 1MB to on-chain max trx size. Note on-chain changes to max_transaction_net_usage do not immediately have to be reflected in enforced value as nodes have right to reject transaction for any reason. Also, since packed_transaction will not be compressed in a block, no zip bomb protection needed. This change is part of the new protocol feature.
• Transmit all P2P packed_transaction uncompressed.
• Add new net protocol that rejects uncompressed and extra data packed_transactions.
• Store all packed_transaction in signed_block including the block log uncompressed.
• In the future, alternative compression schemes could be supported for on-the-wire packed_transaction.
• Continue to support extra data and compressed packed_transaction in blocks until protocol feature is activated. Once protocol feature is activated, blocks with compressed packed_transaction or extra data will be rejected.
• spring-util and nodeos should still be able to read blocks created before the protocol feature is activated that contain compressed packed_transaction or extra data in the packed_transaction.
• Cache uncompressed form in ephemeral cache of packed_transation.
• Remove unused get_raw_transaction()

[greg7mdp]

Disallowing the inclusion of extra, unspecified data within packed_transaction

Would this prevent binary extensions from working?

[heifner]

Disallowing the inclusion of extra, unspecified data within packed_transaction

Would this prevent binary extensions from working?

No, binary extensions extensions_type transaction_extensions; are part of the defined struct of a transaction, so not extra data. Or if you mean the binary extension of an action param then those are part of the action bytes data and are not "extra" in the sense of being unexpected data at the end.

[greg7mdp]

Or if you mean the binary extension of an action param

ah yes I was thinking of that. OK then!