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 in the standard library search path any of the following could cause problemsThe 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 |
|---|
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
PRE04-C | Low | Unlikely | Medium | P2 | L3 |
Automated Detection
| Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Axivion Bauhaus Suite |
| CertC-PRE04 | |||||||
| CC2.PRE04 | Fully implemented | |||||||
| Helix QAC |
| C5001 | |||||||
| LDRA tool suite |
| 568 S | 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" |
...