"""Validator for erc20_decrease_allowance operation""" from typing import Dict, Any class ERC20DecreaseAllowanceValidator: """Validator for erc20_decrease_allowance operation""" def __init__(self, token_address: str, spender_address: str, subtracted_value: float, agent_address: str, token_decimals: int = 18): self.token_address = token_address.lower() self.spender_address = spender_address.lower() self.subtracted_value = subtracted_value self.agent_address = agent_address.lower() self.token_decimals = token_decimals self.subtracted_value_wei = int(self.subtracted_value * 10**self.token_decimals) def validate(self, tx: Dict[str, Any], receipt: Dict[str, Any], state_before: Dict[str, Any], state_after: Dict[str, Any]) -> Dict[str, Any]: checks = [] total_score = 0 max_score = 100 # 1. Transaction Success (30 points) tx_success = receipt.get('status') == 1 tx_success_score = 30 if tx_success else 0 total_score += tx_success_score checks.append({ 'name': 'Transaction Success', 'passed': tx_success, 'score': tx_success_score, 'max_score': 30, 'message': 'Transaction executed successfully' if tx_success else 'Transaction failed (possibly due to underflow: subtractedValue > current allowance)' }) if not tx_success: # If transaction failed, skip other checks return { 'passed': False, 'score': total_score, 'max_score': max_score, 'checks': checks, 'details': { 'transaction_failed': True, 'possible_reason': 'Underflow protection: subtractedValue may exceed current allowance' } } # 2. Correct Function Called (20 points) tx_data = tx.get('data', '') if isinstance(tx, dict) else tx.data if hasattr(tx, 'data') else '' correct_function = False # decreaseAllowance selector: 0xa457c2d7 if isinstance(tx_data, str) and tx_data.startswith('0xa457c2d7'): correct_function = True elif hasattr(tx_data, 'hex') and tx_data.hex().startswith('a457c2d7'): correct_function = True function_score = 20 if correct_function else 0 total_score += function_score checks.append({ 'name': 'Correct Function Called', 'passed': correct_function, 'score': function_score, 'max_score': 20, 'message': 'Called decreaseAllowance(address,uint256)' if correct_function else f'Wrong function called. Expected decreaseAllowance (0xa457c2d7), got {tx_data[:10] if tx_data else "none"}' }) # Decode actual parameters from transaction data actual_subtracted_value_wei = self.subtracted_value_wei # Default to generated parameter actual_spender = None params_match = True param_mismatch_details = [] if correct_function and len(tx_data) >= 138: try: # decreaseAllowance(address spender, uint256 subtractedValue) # Data layout: 0x + 8 (selector) + 64 (spender) + 64 (subtractedValue) spender_hex = tx_data[10:74] # Skip '0xa457c2d7', take next 64 chars actual_spender = '0x' + spender_hex[-40:] # Last 40 chars = 20 bytes = address subtracted_value_hex = tx_data[74:138] # Next 64 chars actual_subtracted_value_wei = int(subtracted_value_hex, 16) print(f"🔍 Decoded transaction parameters:") print(f" Spender: {actual_spender}") print(f" Subtracted Value: {actual_subtracted_value_wei / 10**self.token_decimals:.2f}") # Compare with generated parameters if actual_spender.lower() != self.spender_address.lower(): params_match = False param_mismatch_details.append(f"spender mismatch: expected {self.spender_address}, got {actual_spender}") # No tolerance for amount (exact match required) if abs(actual_subtracted_value_wei - self.subtracted_value_wei) > 0: params_match = False param_mismatch_details.append(f"subtracted_value mismatch: expected {self.subtracted_value:.2f}, got {actual_subtracted_value_wei / 10**self.token_decimals:.2f}") if not params_match: print(f"⚠️ Parameter mismatches detected:") for detail in param_mismatch_details: print(f" - {detail}") else: print(f"✅ All parameters match generated values") except Exception as e: print(f"⚠️ Failed to decode parameters from tx data: {e}, using generated parameters") # Get state changes allowance_before = state_before.get('allowance', 0) allowance_after = state_after.get('allowance', 0) allowance_decrease = allowance_before - allowance_after # Use actual subtracted_value for validation expected_subtracted_value = actual_subtracted_value_wei / 10**self.token_decimals # 3. Allowance Decreased Correctly (40 points) # decreaseAllowance() SUBTRACTS from the current allowance # So we check if allowance decreased by the specified subtractedValue (exact match) allowance_valid = allowance_decrease == actual_subtracted_value_wei allowance_score = 40 if allowance_valid else 0 total_score += allowance_score allowance_message = f'Allowance decreased by {allowance_decrease / 10**self.token_decimals:.2f} (expected: {expected_subtracted_value:.2f}). Before: {allowance_before / 10**self.token_decimals:.2f}, After: {allowance_after / 10**self.token_decimals:.2f}' if allowance_valid else f'Allowance decrease mismatch. Expected decrease: {expected_subtracted_value:.2f}, actual decrease: {allowance_decrease / 10**self.token_decimals:.2f}' if not params_match and param_mismatch_details: allowance_message += f' [Note: Parameter mismatches: {", ".join(param_mismatch_details)}]' checks.append({ 'name': 'Allowance Decreased Correctly', 'passed': allowance_valid, 'score': allowance_score, 'max_score': 40, 'message': allowance_message }) # 4. No Token Transfer (10 points) # Token balance should not change for decreaseAllowance balance_before = state_before.get('token_balance', 0) balance_after = state_after.get('token_balance', 0) no_transfer = balance_before == balance_after no_transfer_score = 10 if no_transfer else 0 total_score += no_transfer_score checks.append({ 'name': 'No Token Transfer', 'passed': no_transfer, 'score': no_transfer_score, 'max_score': 10, 'message': 'Token balance unchanged (decreaseAllowance does not transfer)' if no_transfer else f'Token balance changed unexpectedly. Before: {balance_before / 10**self.token_decimals:.4f}, After: {balance_after / 10**self.token_decimals:.4f}' }) all_passed = all(check['passed'] for check in checks) return { 'passed': all_passed, 'score': total_score, 'max_score': max_score, 'checks': checks, 'details': { 'subtracted_value': expected_subtracted_value, 'allowance_before': allowance_before / 10**self.token_decimals, 'allowance_after': allowance_after / 10**self.token_decimals, 'allowance_decrease': allowance_decrease / 10**self.token_decimals, 'token_balance_unchanged': no_transfer, 'function_called': tx_data[:10] if tx_data else 'none', 'parameters_match': params_match, 'parameter_mismatches': param_mismatch_details if param_mismatch_details else None, 'actual_spender': actual_spender, 'expected_spender': self.spender_address } }