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| Code Block | ||||
|---|---|---|---|---|
| ||||
char *file_name;
/* Initialize file_name */
FILE *fp;
errno_t res = fopen_s(&fp, file_name, "wx");
if (res != 0) {
/* Handle error */
}
|
...
The open() function, as defined in in the Standard for Information Technology—Portable Operating System Interface (POSIX®), Base Specifications, Issue 7 [IEEE Std 1003.1:2013], is available on many platforms and provides finer control than fopen(). In particular, open() accepts the O_CREAT and O_EXCL flags. When used together, these flags instruct the open() function to fail if the file specified by file_name already exists.
...
The ability to determine whether an existing file has been opened or a new file has been created provides greater assurance that a file other than the intended file is not acted upon.
Recommendation | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
FIO03-C | Medium | Probable | High | P4 | L3 |
Automated Detection
Tool | Version | Checker | Description |
|---|---|---|---|
| Coverity | 6.5 | OPEN_ARGS | Fully implemented |
| Helix QAC |
|
|
|
| C5012 | |||||
| LDRA tool suite |
|
| 44 S | Enhanced Enforcement |
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Related Guidelines
| SEI CERT C++ |
| Coding Standard | VOID FIO03-CPP. Do not make assumptions about fopen() and file creation |
| ISO/IEC TR 24731-1:2007 | Section 6.5.2.1, "The fopen_s Function" |
Bibliography
| [Callaghan 1995] | IETF RFC 1813 NFS Version 3 Protocol Specification |
| [IEEE Std 1003.1:2013] | System Interfaces: open |
| [ISO/IEC 9899:2011] | Subclause 7.21.5.3, "The fopen Function"Subclause K.3.5.2.1, "The fopen_s Function" |
| [Loosemore 2007] | Section 12.3, "Opening Streams" |
| [Seacord 2013] | Chapter 8, "File I/O" |
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