RS.DBZ.ITERATOR

Loop iterator might be used in a division by zero

An attempt to do a division or modulo operation using zero as the divisor causes a runtime error. Division by zero defects often occur due to ineffective error handling or race conditions, and typically cause abnormal program termination. Before a value is used as the divisor of a division or modulo operation in Rust code, it must be checked to confirm that it is not equal to zero.

The RS.DBZ checkers look for instances in which a zero constant value is used as the divisor of a division or modulo operation.

The RS.DBZ.ITERATOR checker flags situations in which a loop iterator that has been assigned a zero constant value in the execution of the loop might subsequently be used explicitly or passed to a function that might use it as a divisor of a division or modulo operation without checking it for the zero value.

Vulnerability and risk

Integer division by zero usually result in the failure of the process or an exception. It can also result in success of the operation, but gives an erroneous answer. Floating-point division by zero is more subtle. It depends on the implementation of the compiler.

Division by zero issues typically occur due to ineffective exception handling. To avoid this vulnerability, check for a zero value before using it as the divisor of a division or modulo operation.

External guidance

Limitations

This checker does not deal with abstract symbolic expressions evaluating to zero. This means that defects involving this kind of reasoning may not be detected by this checker.
This checker only deals with loop iterators having a step (or increment) of +1 or -1. This means that defects involving loop iterators having a step different than +1 or -1 will not be detected by this checker.