RS.DBZ.GENERAL
Assigned zero constant value 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.GENERAL checker flags situations in which a variable that has been assigned a zero constant value locally or as the result of a function call 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.
Vulnerable code example
fn zero() -> i32 {
0
}
fn divide(a: i32, b: i32) -> i32 {
a / b
}
fn main() {
let x = zero();
let _y = divide(1, x); // RS.DBZ.GENERAL
}