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The strcpy_s() function defined in C11 Annex K [ISO/IEC 9899:2011] provides additional safeguards, including accepting the size of the destination buffer as an additional argument. (See STR07-C. Use the bounds-checking interfaces for remediation of existing string manipulation code.) Also, strnlen_s() accepts a maximum-length argument for strings that may not be null-terminated.
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If a runtime-constraint error is detected by the call to either strnlen_s() or strcpy_s(), the currently registered runtime-constraint handler is invoked. See ERR03-C. Use runtime-constraint handlers when calling the bounds-checking interfaces for more information on using runtime-constraint handlers with C11 Annex K functions.
Exceptions
STR03-C-EX1: The intent of the programmer is to purposely truncate the string.
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Truncating strings can lead to a loss of data.
Recommendation | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
STR03-C | Medium | Probable | Medium | P8 | L2 |
Automated Detection
Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| CodeSonar |
| MISC.MEM.NTERM | No Space For Null Terminator | ||||||
| Compass/ROSE |
Could detect violations in the following manner: all calls to |
| GCC |
| 8. |
| 1 | -Wstringop-truncation | Detects string truncation by strncat and strncpy. | ||||||
| Klocwork |
| NNTS.MIGHT |
NNTS.MUST | ||||||||
| LDRA tool suite |
| 115 S, 44 S |
Fully implemented
Partially implemented | |||||||||
| Parasoft C/C++test |
| CERT_C-STR03-a | Avoid overflow due to reading a not zero terminated string | ||||||
| Polyspace Bug Finder |
| CERT C: Rec. STR03-C | Checks for invalid use of standard library string routine (rec. partially supported) |
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Related Guidelines
| SEI CERT C++ |
| Coding Standard | VOID STR03-CPP. Do not inadvertently truncate a null-terminated character array |
| ISO/IEC TR 24772:2013 | String Termination [CJM] |
| MITRE CWE | CWE-170, Improper null termination CWE-464, Addition of data structure sentinel |
Bibliography
| [Seacord 2013] | Chapter 2, "Strings" |
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