Construstor - Smart Contract Constructor & Initialize Function Analyzer

A tool for analyzing Solidity smart contracts to detect zero address validation patterns in constructors, initialize functions, and all functions with address parameters.

🚀 Features

• Comprehensive Analysis: Scans individual files or entire directories for .sol files
• Smart Detection:
  • Identifies constructors and initialize functions automatically
  • NEW: Analyzes all functions with address parameters using --all-functions flag
• Advanced Type Recognition:
  • Detects address arrays (address[], address[] memory, address[] calldata)
• Zero Address Validation Detection:
  • Direct equality checks (== address(0), != address(0))
  • require() statements with zero address validation
• Detailed Reporting:
  • Shows which address arguments are validated with full type information
  • Highlights missing validations per argument
  • Provides summary statistics
  • NEW: Complete function definitions displayed in terminal output
• Multiple Output Formats:
  • JSON output without code(--json)
  • Summary-only mode (--summary)
  • Beautiful colored terminal output for human readability

📦 Installation

Prerequisites

• Rust 1.86 or later

Build from Source

git clone https://github.com/oakenknight/construstor.git
cd construstor
cargo build --release

Install from Crates.io

cargo install construstor

The binary will be available at target/release/construstor.

🔧 Usage

Basic Usage

Run the tool with a file or directory:

# Analyze only constructors and initialize functions (default)
construstor MyContract.sol

# Analyze ALL functions with address parameters
construstor MyContract.sol --all-functions

# Output in JSON format
construstor MyContract.sol --json

# Show only summary statistics
construstor MyContract.sol --summary

# Combine flags
construstor MyContract.sol --all-functions --json

# Interactive mode (will prompt for path)
construstor

Command Line Options

• --all-functions / -a: Analyze all functions with address parameters, not just constructors and initialize functions
• --json / -j: Output results in JSON format (excludes code for cleaner output)
• --summary / -s: Show only summary statistics
• --help / -h: Display help information
• --version / -V: Display version information

Example Output

Constructor and Initialize Functions (Default):

Constructor in MyContract.sol:
📋 Found 2 address argument(s): address _owner, address _manager
✅ Zero address validation found:
  • Direct address(0) comparison
  • require() statement with zero address check
    → Checking variable: _owner
    → Checking variable: _manager
✅ All address arguments are validated!
Arguments: address _owner, address _manager
Code:
  constructor(address _owner, address _manager) {
  require(_owner != address(0), "Owner cannot be zero address");
          require(_manager != address(0), "Manager cannot be zero address");
          owner = _owner;
          manager = _manager;
  }

All Functions Analysis (--all-functions):

Function 'setTokens' in MyContract.sol:
📋 Found 3 address argument(s): address _token, address[] memory _addresses, address _fallback
✅ Zero address validation found:
  • require() statement with zero address check
    → Checking variable: _token
❌ Missing zero address validation for:
    ⚠️ Argument: _addresses
    ⚠️ Argument: _fallback
Arguments: address _token, address[] memory _addresses, address _fallback
Code:
  function setTokens(address _token, address[] memory _addresses, address _fallback) {
  require(_token != address(0), "Token cannot be zero");
          // Missing validation for _addresses array and _fallback
  }

📊 Analysis Summary:
  Total functions analyzed: 1
  Functions with address arguments: 1
  Fully validated: 0
  Partially validated: 1
  Not validated: 0

JSON Output (--json):

[
  {
    "function_type": "Constructor",
    "file_name": "MyContract.sol",
    "arguments": "address _owner, address _manager",
    "address_arguments": ["_owner", "_manager"],
    "validated_variables": ["_owner", "_manager"],
    "missing_validations": [],
    "validation_types": ["RequireStatement"]
  }
]

🧪 Testing

Run the test suite:

cargo test

Run tests with verbose output:

cargo test -- --nocapture

📊 What It Detects

Constructor Analysis

constructor(address _owner, address[] memory _tokens) {
    require(_owner != address(0), "Owner cannot be zero");
    // Missing validation for _tokens array ❌
    owner = _owner;
    tokens = _tokens;
}

Initialize Function Analysis

function initialize(address _hookManager, address _test) external initializer {
    require(_hookManager != address(0), "Hook manager cannot be zero address");
    if (_test == address(0)) revert("Test cannot be zero address");
    // Both arguments validated ✅
}

All Functions Analysis (with --all-functions)

function setTokenAddresses(
    address _primary,
    address[] calldata _secondary,
    address storage _fallback
) external onlyOwner {
    require(_primary != address(0), "Primary cannot be zero");
    // Missing validation for _secondary array and _fallback ❌
    primaryToken = _primary;
    secondaryTokens = _secondary;
    fallbackToken = _fallback;
}

Advanced Type Detection

The tool now recognizes various address parameter types:

• Simple addresses: address _owner
• Address arrays: address[] _tokens, address[] memory _list, address[] calldata _external
• Storage keywords: address storage _stored, address memory _temp
• Mixed parameters: Functions with both address and non-address parameters

🏗️ Architecture

The tool is structured with the following key components:

• ConstructorAnalyzer: Core analysis engine with regex-based pattern matching
• AnalysisResult: Structured data representing analysis findings
• ResultPrinter: Pretty-printed output with colors and formatting
• Error Handling: Comprehensive error types and propagation
• Testing: Unit tests covering core functionality

🔍 Detection Patterns

Address Parameter Extraction

• Enhanced Regex: (address(?:\[\])?(?:\s+memory|\s+storage|\s+calldata)?)\s+(\w+)
• Matches:
  • Simple: address _owner, address tokenContract
  • Arrays: address[] _tokens, address[] memory _list
  • Storage: address storage _stored, address calldata _external

Function Detection

• Constructors: constructor\s*\((.*?)\)\s*\{(.*?)\}
• Initialize Functions: function\s+initialize\s*\((.*?)\)\s*[^{]*\{(.*?)\}
• Regular Functions: function\s+(\w+)\s*\((.*?)\)\s*[^{]*\{(.*?)\} (with --all-functions)

Equality Checks

• Regex: (\w+)\s*(?:==|!=)\s*address\(0\)
• Matches: _owner == address(0), token != address(0)

Require Statements

• Regex: (?:require)\s*\(\s*([^,)]+)\s*(?:==|!=)\s*address\(0\)
• Matches: require(_owner != address(0), "message")

🚨 Security Considerations

This tool helps identify potential security vulnerabilities in smart contracts:

• Zero Address Attacks: Prevent accidental or malicious zero address assignments
• Constructor Security: Ensure critical addresses are validated during deployment
• Upgradeable Contracts: Validate addresses in initialize functions for proxy contracts
• Function Security: With --all-functions, catch missing validations in all address-handling functions
• Array Validation: Detect missing validations for address arrays that could contain zero addresses

Exit Codes

• 0: Analysis completed successfully
• 1: Error occurred during analysis (file not found, invalid syntax, etc.)

JSON Output Format

The --json flag outputs clean JSON without code blocks, perfect for:

• Automated security reporting
• Integration with other tools
• Dashboard visualization
• Audit trail generation

🤝 Contributing

1. Fork the repository
2. Create a feature branch: git checkout -b feature/amazing-feature
3. Commit your changes: git commit -m 'Add amazing feature'
4. Push to the branch: git push origin feature/amazing-feature
5. Open a Pull Request

Development Guidelines

• Add tests for new functionality
• Follow Rust naming conventions
• Update documentation for new features
• Ensure cargo clippy passes without warnings

🙏 Acknowledgments

• Rust community for excellent tooling and documentation
• Solidity developers for security best practices
• Smart contract auditing community for inspiration
• Special thanks to Wyatt Chamberlin (@elkaholic6) for giving me the idea with his Solidity-constructor-analysis

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.