If a header file with the same name as one of the a standard headers header is placed in the typical search path to search for libraries then for included source files, the behavior is undefined.
Non-Compliant Example
Naming a header file any of the following could cause problems:
...
The following table from the C Standard, subclause 7.1.2 [ISO/IEC 9899:2011], lists these standard headers:
<assert.h> | <float.h> | <math.h> | <stdatomic.h> | <stdlib.h> | <time.h> |
<complex.h> | <inttypes.h> | <setjmp.h> | <stdbool.h> | <stdnoreturn.h> | <uchar.h> |
<ctype.h> | <iso646.h> | <signal.h> |
...
<stddef.h> | <string.h> | <wchar.h> |
<errno.h> |
...
<limits.h> |
...
<stdalign.h> | <stdint.h> | <tgmath.h> |
...
<wctype.h> |
...
<fenv.h> |
...
<locale.h> |
...
<stdarg.h> |
...
<stdio.h> |
...
<threads.h> |
...
Do not reuse standard header file names, system-specific header file names, or other header file names.
Noncompliant Code Example
In this noncompliant code example, the programmer chooses to use a local version of the standard library but does not make the change clear:
| Code Block | ||||
|---|---|---|---|---|
| ||||
#include "stdio.h" /* Confusing, distinct from <stdio.h> */
/* ... */
|
Compliant Solution
The solution addresses the problem by giving the local library a unique name (per PRE08-C. Guarantee that header file names are unique), which makes it apparent that the library used is not the original:
| Code Block | ||||
|---|---|---|---|---|
| ||||
/* Using a local version of stdio.h */
#include "mystdio.h"
/* ... */
|
Risk Assessment
Using header file names that conflict with other header file names can result in an incorrect file being included.
Recommendation | Severity | Likelihood | Detectable | Repairable | Priority | Level |
|---|---|---|---|---|---|---|
PRE04-C | Low | Unlikely | Yes | No | P2 | L3 |
Automated Detection
| Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Axivion Bauhaus Suite |
| CertC-PRE04 | |||||||
| Cppcheck Premium |
| premium-cert-pre04-c | |||||||
| CC2.PRE04 | Fully implemented | |||||||
| Helix QAC |
| C5001 | |||||||
| LDRA tool suite |
| 568 S | Fully implemented | ||||||
| Polyspace Bug Finder |
| Checks for reuse of standard header file (rec. fully covered) | |||||||
| Security Reviewer - Static Reviewer |
| RTOS_22 | Fully implemented |
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Related Guidelines
| SEI CERT C++ Coding Standard | VOID PRE04-CPP. Do not reuse a standard header file name |
| CERT Oracle Secure Coding Standard for Java | DCL01-J. Do not reuse public identifiers from the Java Standard Library |
Bibliography
| [ISO/IEC 9899:2011] | Subclause 7.1.2, "Standard Headers" |
...
Risk Assessment
It is possible that an attacker could place a duplicate header file in the library path in order to cause exploit behavior.
Rule | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
| 2 (medium) | 1 (unlikely) | 3 (low) | P2 | L2 |
References
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