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| Code Block | ||||
|---|---|---|---|---|
| ||||
char *improved_strncpy(char * restrict s1, size_t s1count, const char * restrict s2, size_t s2count, size_t n); char *improved_strncat(char * restrict s1, size_t s1count, const char * restrict s2, size_t s2count, size_t n); |
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There are two notable differences between the compliant solution and the secure versions from Annex K. First, the Annex K versions use rsize_t instead of size_t, which allows the size to be compared against the reasonable limit for a single object, RSIZE_MAX. Second, the Annex K versions do not require an element count for the second array. Consequently, these functions have limited ability to validate the input for s2. However, a size value for s1 is required, so memory outside of the range for s1 should not be overwritten.
Exceptions
API02-C-EX1: Functions that can guarantee via their runtime-constraint handlers that no out-of-bounds read or write occurs may omit the maximum-elements argument. For instance, the s2 parameter to strcat_s() needs no max parameter.
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Failure to follow this recommendation can result in improper memory accesses and buffer overflows that are detrimental to the correct and continued execution of the program.
Rule | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
API02-C | High | Likely | High | P9 | L2 |
Automated Detection
Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| CodeSonar |
| BADFUNC.BO.* | A collection of checks that report uses of library functions prone to internal buffer overflows. | ||||||
| Parasoft C/C++test |
| CERT_C-API02-a | Avoid using unsafe string functions which may cause buffer overflows |
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Related Guidelines
Key here (explains table format and definitions)
Bibliography
| [ISO/IEC 9899:2011] | Annex K (normative) Bounds-checking Interfaces |
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