Last updated: March 11, 2025

SCWE-032: Dependency on Block Gas Limit

Stable Version v0.0.1

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Relationships

• CWE-400: Uncontrolled Resource Consumption
  CWE-400 Link

Description

Dependency on block gas limit refers to the reliance on the Ethereum block gas limit for contract operations, which can lead to: - Failed transactions if gas limits are exceeded. - Exploitation of vulnerabilities in gas-intensive operations. - Loss of funds or data.

Remediation

• Optimize gas usage: Minimize gas consumption in contract operations.
• Avoid unbounded loops: Ensure loops have a fixed upper limit.
• Test thoroughly: Conduct extensive testing to ensure operations stay within gas limits.

Examples

• Gas-Intensive Operation- Storing Large Dynamic Data

  pragma solidity ^0.8.0;
  
  contract GasIntensive {
      uint[] public largeArray;
  
      function appendData(uint[] memory data) public {
          for (uint i = 0; i < data.length; i++) {
              largeArray.push(data[i]); // Storing a large dataset in a single transaction
          }
      }
  }
  

• This contract appends large arrays in a single transaction, which fails when the block gas limit is exceeded.

• Attackers could exploit this by forcing high gas consumption and causing DoS attacks (e.g., filling storage inefficiently).

• Optimized Gas Usage- Chunk Processing & Gas Efficiency

  pragma solidity ^0.8.0;
  
  contract GasOptimized {
      uint[] public largeArray;
  
      function appendData(uint[] memory data, uint start, uint end) public {
          require(end <= data.length, "Invalid range");
          for (uint i = start; i < end; i++) {
              largeArray.push(data[i]); // Process in controlled batches
          }
      }
  }
  

Why is this better? - The start and end parameters allow batch processing instead of handling everything in a single call. - Prevents hitting the block gas limit by splitting work across multiple transactions.

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