CWE-369 除零错误

Divide By Zero

结构: Simple

Abstraction: Base

状态: Draft

被利用可能性: Medium

基本描述

The product divides a value by zero.

扩展描述

This weakness typically occurs when an unexpected value is provided to the product, or if an error occurs that is not properly detected. It frequently occurs in calculations involving physical dimensions such as size, length, width, and height.

相关缺陷

  • cwe_Nature: ChildOf cwe_CWE_ID: 682 cwe_View_ID: 1000 cwe_Ordinal: Primary

  • cwe_Nature: ChildOf cwe_CWE_ID: 682 cwe_View_ID: 1003 cwe_Ordinal: Primary

  • cwe_Nature: ChildOf cwe_CWE_ID: 682 cwe_View_ID: 699 cwe_Ordinal: Primary

常见的影响

范围 影响 注释
Availability DoS: Crash, Exit, or Restart A Divide by Zero results in a crash.

示例代码

例

The following Java example contains a function to compute an average but does not validate that the input value used as the denominator is not zero. This will create an exception for attempting to divide by zero. If this error is not handled by Java exception handling, unexpected results can occur.

bad Java

public int computeAverageResponseTime (int totalTime, int numRequests) {
return totalTime / numRequests;
}

By validating the input value used as the denominator the following code will ensure that a divide by zero error will not cause unexpected results. The following Java code example will validate the input value, output an error message, and throw an exception.

good

public int computeAverageResponseTime (int totalTime, int numRequests) throws ArithmeticException {
if (numRequests == 0) {
System.out.println("Division by zero attempted!");
throw ArithmeticException;
}
return totalTime / numRequests;
}

例

The following C/C++ example contains a function that divides two numeric values without verifying that the input value used as the denominator is not zero. This will create an error for attempting to divide by zero, if this error is not caught by the error handling capabilities of the language, unexpected results can occur.

bad C

double divide(double x, double y){
return x/y;
}

By validating the input value used as the denominator the following code will ensure that a divide by zero error will not cause unexpected results. If the method is called and a zero is passed as the second argument a DivideByZero error will be thrown and should be caught by the calling block with an output message indicating the error.

good

const int DivideByZero = 10;
double divide(double x, double y){
if ( 0 == y ){
throw DivideByZero;
}
return x/y;
}
...
try{
divide(10, 0);
}
catch( int i ){
if(i==DivideByZero) {
cerr<<"Divide by zero error";
}
}

例

The following C# example contains a function that divides two numeric values without verifying that the input value used as the denominator is not zero. This will create an error for attempting to divide by zero, if this error is not caught by the error handling capabilities of the language, unexpected results can occur.

bad C#

int Division(int x, int y){
return (x / y);
}

The method can be modified to raise, catch and handle the DivideByZeroException if the input value used as the denominator is zero.

good

int SafeDivision(int x, int y){
try{
return (x / y);
}
catch (System.DivideByZeroException dbz){
System.Console.WriteLine("Division by zero attempted!");
return 0;
}
}

分析过的案例

标识 说明 链接
CVE-2007-3268 Invalid size value leads to divide by zero. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3268
CVE-2007-2723 "Empty" content triggers divide by zero. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-2723
CVE-2007-2237 Height value of 0 triggers divide by zero. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-2237

分类映射

映射的分类名 ImNode ID Fit Mapped Node Name
OWASP Top Ten 2004 A9 CWE More Specific Denial of Service
CERT C Secure Coding FLP03-C Detect and handle floating point errors
CERT C Secure Coding INT33-C Exact Ensure that division and remainder operations do not result in divide-by-zero errors
The CERT Oracle Secure Coding Standard for Java (2011) NUM02-J Ensure that division and modulo operations do not result in divide-by-zero errors
Software Fault Patterns SFP1 Glitch in computation