Alternative functions that limit the number of bytes copied are often recommended to mitigate buffer overflow vulnerabilities. For example

These functions truncate strings that exceed the specified limits. Additionally, some functions such as {{strncpy()}} do not guarantee that the resulting string is null terminated \[[STR32-C. Null terminate byte strings as required]\].

Unintentional truncation results in a loss of data and, in some cases, leads to software vulnerabilities.

Exceptions

STR03-EX1: The intent of the programmer is to intentionally truncate the null-terminated byte string.

Risk Assessment

Truncating strings can lead to a loss of data.

Recommendation

Severity

Likelihood

Remediation Cost

Priority

Level

STR03-A

1 (low)

1 (unlikely)

2 (medium)

P2

L3

Automated Detection

The LDRA tool suite V 7.6.0 is able to detect violations of this recommendation.

Fortify SCA Version 5.0 with CERT C Rule Pack can detect violations of this recommendation.

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

References

\[[ISO/IEC 9899-1999|AA. C References#ISO/IEC 9899-1999]\] Section 7.21, "String handling <string.h>"
\[[Seacord 05a|AA. C References#Seacord 05a]\] Chapter 2, "Strings"
\[[ISO/IEC TR 24731-1-2007|AA. C References#ISO/IEC TR 24731-1-2007]\]


STR02-A. Sanitize data passed to complex subsystems      07. Characters and Strings (STR)       STR05-A. Prefer making string literals const-qualified