slibc

Introduction

This library provides an implementation of the bounds-checking C functions (as specified in Annex K of the current C standard, a.k.a. C11) for use with the GNU C library.

These functions lower the risk of introducing security vulnerabilities such as buffer overflows and format string vulnerabilities into your code by providing clear and easy-to-use interfaces. For each C function a secure alternate function ending in a _s postfix is provided (e.g., strcpy_s). Use of these functions is recommended by security experts and secure coding standards (CERT Secure Coding Standard C).

This library consists of:

• a thread-safe implementation of all functions specified in the ISO Standard (except widechar functions)
• API documentation for all functions
• test cases for all functions
• overloaded C++ template functions for easier use when compiling with g++

How to compile the library

1. Compile the slibc libary by typing make. Slibc is compiled as a shared library (libslibc.so). To link with the shared library, add -lslibc to your linker step.
2. Optionally run all tests by executing make test.

Use SLIBC with your program

1. Use the new _s functions in your code:

#include <string.h>

int main(int argc, char *argv[])
{
  char dest[10];
  strcpy_s(dest, sizeof(dest), argv[0]);
}

2. When compiling include the SLIBC header directory (include/slibc) in your compiler's include path (e.g., add -I~/slibc/include/slibc). Remember that Annex K adds functions to the standard C library by extending existing header files. SLIBC makes the fact that it's a third-party library (instead of being part of GLIBC) as transparent as possible to your program. To use strcpy_s, simply include string.h in your program. It is important that your compiler searches in the slibc header directory first.
3. Link your program to Slibc. Slibc is built as a shared library. Add -lslibc to your linking step. Additionally, you might have to add the location of slibc's so-files to your Linker search path by adding -L (e.g., -L../src/).
4. Run your program. If the Slibc shared object file cannot be found, you have to adjust the environment variable LD_LIBRARY_PATH.

Directory layout

• include/slibc: contains the public header files
• src/: contains the implementation
• tests_slibc/: contains our c++ based test-suite for slibc
• tests_ow/: contains the open watcom tests.