Research on Bytecode Rewriting and Upgrading of Smart Contracts

Research on Bytecode Rewriting and Upgrading of Smart Contracts

A distributed database in a blockchain network that maintains a growing list of data records that is difficult to tamper with or modify, even by the node operators that store the data. Bytecode Compiled code, usually in a platform-independent binary format. EVM Ethereum Virtual Machine, a stack-based virtual machine used to execute Ethereum smart contracts. Vulnerability Errors or defects in smart contract code that can be exploited by attackers. Patch Code modification used to fix vulnerabilities. Rewrite tool Tool used to modify smart contract bytecode to include patches. Deployment component Component used to deploy patched smart contracts to a blockchain network. Upgrade transaction Special transaction used to update patched smart contract code to a blockchain network. Trampoline code A code rewriting technique that replaces a block of code to be patched with a jump instruction that jumps to a patched block of code elsewhere in the code.

Briefly describe the role of smart contracts in blockchain networks.

Smart contracts are programs stored on a blockchain that are automatically executed when preset conditions are met. They are used to implement decentralized applications in blockchain networks and automatically execute the terms of the agreement.

Why do traditional software update methods not work for blockchain smart contracts?

Smart contracts on blockchains are usually designed to be immutable, which means that they cannot be directly modified once deployed. Traditional software update methods rely on modifying existing code and are therefore not applicable to smart contracts.

How does the proposed smart contract upgrade method work?

A smart contract upgrade method based on bytecode rewriting is proposed. First, vulnerabilities in smart contracts are identified and corresponding patch codes are generated. Then, the patch code is inserted into the original bytecode using a rewriting tool to generate new bytecode. Finally, the new bytecode is deployed to the blockchain network through an upgrade transaction to replace the old contract code.

What are the advantages of the bytecode rewriting method over other smart contract upgrade methods?

The bytecode rewriting method does not require access to the source code of the smart contract and does not rely on a specific compiler version, so it has a wider applicability. In addition, bytecode rewriting can achieve more sophisticated code modifications, such as patching only specific vulnerabilities without affecting other functions of the contract.

What role does "trampoline code" play in smart contract upgrades?

"Trampoline code" is a code rewriting technique used to insert new code without changing the address of the original code. In smart contract upgrades, "trampoline code" can be used to insert jump instructions into the original contract code, so that the program jumps to the new patch code block for execution, and jumps back to the original code sequence to continue execution after execution.

How to ensure that the new contract is logically consistent with the old contract during the smart contract upgrade process?

In order to ensure that the new contract is logically consistent with the old contract, strict testing and verification are required. Existing testing tools can be used to perform unit testing and integration testing on the new contract and compare it with the behavior of the old contract. In addition, formal verification and other techniques can be used to verify the logic of the new contract to ensure that it meets expectations.

What type of smart contract vulnerabilities does the proposed method mainly target?

The proposed method can be used to fix various types of smart contract vulnerabilities, but the main focus is on integer overflow vulnerabilities. Integer overflow vulnerabilities are a common security vulnerability that can be exploited by attackers to steal funds or control smart contracts.

Briefly describe the process of the proposed smart contract upgrade method.

Identify vulnerabilities and generate patch code. 2. Use bytecode rewriting tools to insert patch code into the original bytecode. 3. Test and verify the patched contract to ensure its logical consistency. 4. Deploy the new bytecode to the blockchain network through an upgrade transaction.

What is the significance of the proposed method for smart contract developers?

The proposed method provides a safe and efficient contract upgrade solution for smart contract developers, which can help developers fix vulnerabilities in a timely manner and improve the security of contracts.

What are the limitations of the proposed method?

The proposed method also has some limitations, such as: it needs to rely on specific bytecode rewriting tools, which has certain requirements on the technical level of developers. In addition, for some complex smart contracts, bytecode rewriting may be difficult