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).

News

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Latest Release

• Jul 20, 2014: Slibc 0.9.3 released Download | Introduction to Slibc | API documentation

For a quick overview of the changes in the latest version, have a look at the Changelog

Repositories

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Motivation

Consider the following code and ask yourself which of the following operations are correct in the sense that they do not cause a buffer overflow or leave a string without a terminating null byte. char buf[10];  strncpy(buf, "123", strlen("123")); //will leave buf without a terminating null byte strncpy(buf, "123", sizeof(buf); //in this case correct strncpy(buf, "123456789A", 9); //will leave buf without a terminating null byte memset(buf, '\0', sizeof(buf));     strncat(buf, "123456789A", sizeof(buf)); // buffer overflow because strncat always adds a terminating null byte

Would it not be easier if you had the possibility to specify the size of a target buffer and not worry that the implementation will overwrite memory? This is what this library and their _s functions are for.

char buf[10];  strcpy_s(buf, sizeof(buf), "123"); strcpy_s(buf, sizeof(buf), "123"); strcpy_s(buf, sizeof(buf), "123456789A"); //buf is not big enough, thus no copying will take place memset_s(buf, sizeof(buf), '\0', sizeof(buf));
strcat_s(buf, sizeof(buf), "123456789A"); //buf is not big enough, thus no copying will take place

Implementation

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++

About

Slibc was implemented by the SSG team of SBA Research, Austria. The main contributors of this project are Ulrich Bayer (ubayer@sba-research.org) and Peter Aufner (paufner@sba-research.org).