This managed string library was developed in response to the need for a string library that could improve the quality and security of newly developed C language programs while eliminating obstacles to widespread adoption and possible standardization.
The managed string library is based on a dynamic approach in that memory is allocated and reallocated as required. This approach eliminates the possibility of unbounded copies, null-termination errors, and truncation by ensuring there is always adequate space available for the resulting string (including the terminating null character).
A runtime-constraint violation occurs when memory cannot be allocated. In this way, the managed string library accomplishes the goal of succeeding or failing loudly.
The managed string library also provides a mechanism for dealing with data sanitization by (optionally) checking that all characters in a string belong to a predefined set of "safe" characters.
Priority: P6 Level: L1
String handling functions defined in C99 Section 7.21 and elsewhere are susceptible to common programming errors that can lead to serious, exploitable vulnerabilities. Managed strings, when used properly, can eliminate many of these errors--particularly in new development.
Component |
Value |
|---|---|
Severity |
3 (medium) |
Likelihood |
2 (probable) |
Remediation cost |
1 (high) |
References
- Burch 06
- Managed String Library http://www.cert.org/secure-coding/managedstring.html
- ISO/IEC 9899-1999 Section 7.21 String handling <string.h>
- Seacord 05a Chapter 2 Strings