QuantAMM

Summary

The QuantAMMGradientBasedRule contract contains multiple instances of unchecked arithmetic operations and unsafe loop increments that could lead to overflows, underflows, and potential division by zero errors. These issues could result in incorrect gradient calculations and potentially compromise the pool's weight updates.

Vulnerability Details

The vulnerabilities are present in several critical areas of the contract:
https://github.com/Cyfrin/2024-12-quantamm/blob/a775db4273eb36e7b4536c5b60207c9f17541b92/pkg/pool-quantamm/contracts/rules/base/QuantammGradientBasedRule.sol#L71-L101

1. Unchecked Loop Increments:

1. Unsafe Power and Division Operations:
   https://github.com/Cyfrin/2024-12-quantamm/blob/a775db4273eb36e7b4536c5b60207c9f17541b92/pkg/pool-quantamm/contracts/rules/base/QuantammGradientBasedRule.sol#L61

1. Unchecked Arithmetic in Gradient Calculations:
   https://github.com/Cyfrin/2024-12-quantamm/blob/a775db4273eb36e7b4536c5b60207c9f17541b92/pkg/pool-quantamm/contracts/rules/base/QuantammGradientBasedRule.sol#L73-L75

https://github.com/Cyfrin/2024-12-quantamm/blob/a775db4273eb36e7b4536c5b60207c9f17541b92/pkg/pool-quantamm/contracts/rules/base/QuantammGradientBasedRule.sol#L84-L88

1. Unchecked Array Access:
   https://github.com/Cyfrin/2024-12-quantamm/blob/a775db4273eb36e7b4536c5b60207c9f17541b92/pkg/pool-quantamm/contracts/rules/base/QuantammGradientBasedRule.sol#L92-L95

Impact

The vulnerabilities could lead to:

• Silent overflows/underflows in weight calculations

• Incorrect gradient computations due to arithmetic errors

• Potential division by zero errors

• Array access out of bounds

• Accumulation of computational errors in loop iterations

• Potential manipulation of pool weights through carefully crafted inputs

Severity: High, as these issues could affect the core functionality of the pool's weight calculations and potentially lead to financial losses.

Tools Used

• Manual code review

Recommendations

1. Add Input Validation:

1. Implement Safe Arithmetic:

1. Add Bounds Checking:

1. Implement Value Range Validation:

1. Consider Using SafeMath:

• For critical calculations, consider using SafeMath library even with Solidity 0.8+ to ensure explicit checks

• Add explicit overflow checks for important arithmetic operations

1. Add Circuit Breakers:

• Implement maximum and minimum thresholds for gradient values

• Add emergency stops if calculations exceed safe bounds

1. Improve Documentation:

• Document expected value ranges for all parameters

• Add explicit warnings about potential numerical limitations

• Document assumptions about input values and their relationships