A function returns the address of a stack variable, which will cause unintended program behavior, typically in the form of a crash.
Time of Introduction
Implementation
Applicable Platforms
Languages
C
C++
Common Consequences
Scope
Effect
Availability
Technical Impact: DoS: crash / exit /
restart
Demonstrative Examples
Example 1
The following function returns a stack address.
(Bad Code)
Example
Language: C
char* getName() {
char name[STR_MAX];
fillInName(name);
return name;
}
Potential Mitigations
Phase: Testing
Use static analysis tools to spot return of the address of a stack
variable.
Other Notes
Because local variables are allocated on the stack, when a program returns
a pointer to a local variable, it is returning a stack address. A subsequent
function call is likely to re-use this same stack address, thereby
overwriting the value of the pointer, which no longer corresponds to the
same variable since a function's stack frame is invalidated when it returns.
At best this will cause the value of the pointer to change unexpectedly. In
many cases it causes the program to crash the next time the pointer is
dereferenced. The problem can be hard to debug because the cause of the
problem is often far removed from the symptom.
Description
