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S1C6: Meet All The Conditions
1. Problem
The mintFlag function has multiple condition checks: (1) points < THRESHOLD (2) points x levels >= MIN_POWER (3) certain bitwise operation conditions. All of these seemingly contradictory constraints must be satisfied simultaneously.
2. Root Cause
The contract uses multiple conditions to restrict mintFlag, but there are logical vulnerabilities between the conditions. By carefully computing parameter combinations, all conditions can be satisfied at the same time.
3. Solution
Analyze the constraint space of each condition, find specific parameter values that satisfy all conditions, then call the function through a deployed contract.
4. Pitfalls Encountered
Conflicting conditions: Some conditions appear to conflict with each other, such as points needing to be less than a threshold while points x levels must be greater than another threshold.
5. Why the Pitfall Exists
The contract designer did not account for the mathematical properties at boundary conditions, making seemingly contradictory conditions simultaneously satisfiable under specific parameter values.
6. How to Resolve
Identify feasible solutions in the parameter space through mathematical analysis. Use Foundry fork testing to test different parameter combinations.
7. Key Takeaways
| Point | Explanation |
|---|---|
| Multiple constraint conditions | The constraint spaces of multiple require statements may have intersections |
| Boundary value analysis | Requires analyzing the boundary behavior of uint types |
| Solidity integer arithmetic | Features like multiplication overflow and division rounding can produce non-intuitive results |