Difference between revisions of "Assigning instead of comparing"

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[[Category:OWASP ASDR Project]]
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[[ASDR Table of Contents]]__TOC__
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==Overview==
 
==Overview==
  
In many languages the compare statement is very close in appearance to the assignment statement and are often confused.
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In many languages, the '''compare''' statement is very close in appearance to the '''assignment''' statement and are often confused.
  
 
==Consequences ==
 
==Consequences ==
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* Implementation: Many logic errors can lead to this condition. It can be exacerbated by lack, or misuse, of mitigating technologies.  
 
* Implementation: Many logic errors can lead to this condition. It can be exacerbated by lack, or misuse, of mitigating technologies.  
  
==PlatforM ==
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==Platform ==
  
 
* Languages: C, C++
 
* Languages: C, C++

Revision as of 17:37, 20 September 2008


ASDR Table of Contents


Overview

In many languages, the compare statement is very close in appearance to the assignment statement and are often confused.

Consequences

Unspecified.

Exposure period

  • Pre-design through Build: The use of tools to detect this problem is recommended.
  • Implementation: Many logic errors can lead to this condition. It can be exacerbated by lack, or misuse, of mitigating technologies.

Platform

  • Languages: C, C++
  • Operating platforms: Any

Required resources

Any

Severity

High

Likelihood of exploit

Low

Avoidance and mitigation

  • Pre-design: Through Build: Many IDEs and static analysis products will detect this problem.
  • Implementation: Place constants on the left. If one attempts to assign a constant with a variable, the compiler will of course produce an error.

Discussion

This bug is generally as a result of a typo and usually should cause obvious problems with program execution. If the comparison is in an if statement, the if statement will always return the value of the right-hand side variable.

Examples

In C/C++/Java:

void called(int foo){
        if (foo=1)  printf("foo\n");
}

int main(){
        called(2);
        return 0;
}

Related problems

Comparing instead of assigning