File size: 6,395 Bytes
edbc049
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
"""
ERC20 Revoke Approval Validator

Validates that ERC20 approval was successfully revoked (allowance set to zero)
"""

from typing import Dict, Any


class ERC20RevokeApprovalValidator:
    """Validator for ERC20 revoke approval transactions"""
    
    def __init__(self, token_address: str, spender_address: str):
        """
        Initialize validator
        
        Args:
            token_address: ERC20 token contract address
            spender_address: Address whose approval should be revoked
        """
        self.expected_token = token_address.lower()
        self.expected_spender = spender_address.lower()
        self.max_score = 100
    
    def validate(
        self,
        tx: Dict[str, Any],
        receipt: Dict[str, Any],
        state_before: Dict[str, Any],
        state_after: Dict[str, Any]
    ) -> Dict[str, Any]:
        """
        Validate the transaction execution results
        
        Args:
            tx: Transaction object
            receipt: Transaction receipt
            state_before: Blockchain state before transaction
            state_after: Blockchain state after transaction
            
        Returns:
            Validation results including score and details
        """
        score = 0
        details = {}
        checks = []
        
        # Check 1: Transaction success (30 points)
        tx_success = receipt.get('status') == 1
        if tx_success:
            score += 30
            checks.append({
                'name': 'Transaction Success',
                'passed': True,
                'points': 30,
                'message': 'Transaction executed successfully'
            })
        else:
            checks.append({
                'name': 'Transaction Success',
                'passed': False,
                'points': 0,
                'message': f"Transaction failed with status: {receipt.get('status')}"
            })
            return {
                'score': score,
                'max_score': self.max_score,
                'passed': False,
                'checks': checks,
                'details': details
            }
        
        # Check 2: Token contract address correct (20 points)
        actual_to = tx.get('to', '').lower()
        contract_correct = actual_to == self.expected_token
        
        if contract_correct:
            score += 20
            checks.append({
                'name': 'Token Contract',
                'passed': True,
                'points': 20,
                'message': f'Correct token contract: {self.expected_token}'
            })
        else:
            checks.append({
                'name': 'Token Contract',
                'passed': False,
                'points': 0,
                'message': f'Expected: {self.expected_token}, Got: {actual_to}'
            })
        
        details['expected_token'] = self.expected_token
        details['actual_to'] = actual_to
        
        # Check 3: Function signature (20 points)
        # ERC20 approve function selector: 0x095ea7b3 (keccak256("approve(address,uint256)"))
        tx_data = tx.get('data', '0x')
        
        if tx_data and len(tx_data) >= 10:
            function_selector = tx_data[:10].lower()
            expected_selector = '0x095ea7b3'  # approve(address,uint256)
            
            if function_selector == expected_selector:
                score += 20
                checks.append({
                    'name': 'Function Signature',
                    'passed': True,
                    'points': 20,
                    'message': 'Correct ERC20 approve function signature'
                })
                
                # Decode parameters from data
                try:
                    if len(tx_data) >= 138:  # 0x(2) + selector(8) + spender(64) + amount(64) = 138
                        spender_hex = tx_data[10:74]  # Next 64 chars (32 bytes)
                        amount_hex = tx_data[74:138]  # Next 64 chars (32 bytes)
                        
                        # Extract address (last 40 hex chars of the 64 char field)
                        spender_addr = '0x' + spender_hex[-40:].lower()
                        amount_value = int(amount_hex, 16)
                        
                        details['decoded_spender'] = spender_addr
                        details['decoded_amount'] = amount_value
                except Exception as e:
                    details['decode_error'] = str(e)
            else:
                checks.append({
                    'name': 'Function Signature',
                    'passed': False,
                    'points': 0,
                    'message': f'Expected: {expected_selector}, Got: {function_selector}'
                })
        else:
            checks.append({
                'name': 'Function Signature',
                'passed': False,
                'points': 0,
                'message': 'No data field or too short'
            })
        
        details['function_selector'] = tx_data[:10] if tx_data else None
        
        # Check 4: Allowance revoked (set to 0) (30 points)
        allowance_before = state_before.get('allowance', 0)
        allowance_after = state_after.get('allowance', 0)
        
        # Allowance should be 0 after revoke
        allowance_revoked = allowance_after == 0
        
        if allowance_revoked:
            score += 30
            checks.append({
                'name': 'Allowance Revoked',
                'passed': True,
                'points': 30,
                'message': f'Allowance successfully revoked (before: {allowance_before}, after: 0)'
            })
        else:
            checks.append({
                'name': 'Allowance Revoked',
                'passed': False,
                'points': 0,
                'message': f'Allowance not revoked (expected: 0, got: {allowance_after})'
            })
        
        details['allowance_before'] = allowance_before
        details['allowance_after'] = allowance_after
        details['expected_spender'] = self.expected_spender
        
        # Final result
        passed = score >= self.max_score * 0.8  # 80% threshold
        
        return {
            'score': score,
            'max_score': self.max_score,
            'passed': passed,
            'checks': checks,
            'details': details
        }