secure integer library

[pmeunier at cerias.purdue.edu (Pascal Meunier)]

Nice.  I'll mention it in my secure programming class this semester.  I'd be
interested in any exercises/labs based on it, appropriate for undergrads.

Cheers,
Pascal


On 8/17/06 10:04 AM, "Robert C. Seacord" <rcs at cert.org> wrote:

> The CERT/CC has released a beta version of a secure integer library for
> the C Programming Language.  The library is available for download from
> the CERT/CC Secure Coding Initiative web page at:
> http://www.cert.org/secure-coding/
>
> The purpose of this library is to provide a collection of utility
> functions that can assist software developers in writing C programs that
> are free from common integer problems such as integer overflow, integer
> truncation, and sign errors that are a common source of software
> vulnerabilities.
>
> Functions have been provided for all integer operations subject to
> overflow such as addition, subtraction, multiplication, division, unary
> negation, etc.) for int, long, long long, and size_t integers.  The
> following example illustrates how the library can be used to add two
> signed long integer values:
>
> long retsl, xsl, ysl;
> xsl = LONG_MAX;
> ysl = 0;
> retsl = addsl(xsl,ysl);
>
> For short integer types (char and short) it is necessary to truncate the
> result of the addition using one of the safe conversion functions
> provided, for example:
>
> char retsc, xsc, ysc;
> xsc = SCHAR_MAX;
> ysc = 0;
> retsc = si2sc(addsi(xsc, ysc));
>
> For error handling, the secure integer library uses the mechanism for
> Runtime-constraint handling defined by TR 24731 "Specification for
> Safer, More Secure C Library Functions" available at:
> http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1135.pdf
>
> The implementation uses the high performance algorithms defined by Henry
> S. Warren in the book "Hacker's Delight".
>
> For more information on vulnerabilities and other problems resulting
> from the incorrect use of integers in C and C++ please read Chapter 5 of
> "Secure Coding in C and C++" which is available as a free download from
> the CERT web site:
>
> http://www.cert.org/books/secure-coding/moreinfo.html
>
> Please address any defect reports, comments and suggestions concerning
> the Secure Integer Library or CERT Secure Coding Initiative to me.
> Thanks to Henry and to Juan Alvarado who coded the implementation.
>
> Thanks,
> rCs