If a file with the same name as a standard header is placed in the search path for included source files, the behavior is undefined.
The following table from the C Standard, section 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 | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
PRE04-C | low | unlikely | medium | P2 | L3 |
Automated Detection
| Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| hedrname | Fully implemented | |||||||
| 218 S | Fully implemented | |||||||
| PRQA QA-C |
| Secondary analysis | Fully implemented |
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Related Guidelines
| CERT C++ Secure Coding Standard | 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] | Section 7.1.2, "Standard Headers" |