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According to the C Standard, 6.2.4, paragraph 2 [ISO/IEC 9899:20112024],

The lifetime of an object is the portion of program execution during which storage is guaranteed to be reserved for it. An object exists, has a constant address, and retains its last-stored value throughout its lifetime. If an object is referred to outside of its lifetime, the behavior is undefined. The value of If a pointer becomes indeterminate when value is used in an evaluation after the object it the pointer points to (or just past) reaches the end of its lifetime, the behavior is undefined.

Do not attempt to access an object outside of its lifetime. Attempting to do so is undefined behavior and can lead to an exploitable vulnerability. (see See also undefined behavior 9 in the C Standard, Annex J.).

Noncompliant Code Example (Differing Storage Durations)

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Some compilers generate a diagnostic message when a pointer to an object with automatic storage duration is returned from a function, as in this example. Compile your Programmers should compile code at high warning levels and resolve any diagnostic messages. (see See MSC00-C. Compile cleanly at high warning levels.).

Compliant Solution (Return Values)

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#include <stddef.h>
void init_array(char *array, size_t len) {
  /* Initialize array */
  return;
}

int main(int argc, char *argv[]void) {
  char array[10];
  init_array(array, sizeof(array) / sizeof(array[0]));
  /* ... */
  return 0;
}

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Referencing an object outside of its lifetime can result in an attacker being able to execute arbitrary code.

Automated Detection

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

Related Guidelines

Key here (explains table format and definitions)

CERT-CWE Mapping Notes

Key here for mapping notes

CWE-562 and DCL30-C

DCL30-C = Union( CWE-562, list) where list =

• Assigning a stack pointer to an argument (thereby letting it outlive the current function

Bibliography

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