MissingNegativityTest.qhelp

<!DOCTYPE qhelp PUBLIC
  "-//Semmle//qhelp//EN"
  "qhelp.dtd">
<qhelp>


<overview>
<p>
This rule finds pointer arithmetic expressions that use a value returned from a function before the value is checked to be positive.
Most pointer arithmetic and almost all array element accesses use a positive value for offsets. A negative value is more likely than not
a defect in the returning function. Checking pointer offsets (particularly if they derive from user input) is necessary to avoid 
buffer overruns.
</p>

<p>
The rules only looks at return values of functions that may return a negative value (not all functions).
</p>


<include src="dataFlowWarning.qhelp" />

</overview>
<recommendation>
<p>
Check the function and see whether it needs to check the value to be positive.
</p>

</recommendation>
<example>
<sample src="MissingNegativityTest.cpp" />






</example>
</qhelp>