Runtime security/memory checks for gcc/gdb

[Elazar Leibovich]

Just a remark, as some people asked me about it privately.
I'm not interested in static analysis (which gcc gives for uninitialized
variables). But with runtime analysis of where the uninitialized variable
have been actually used when the code was run. This is useful in many
situations (for instance, when having 3000 (literally) static warnings, some
of similar spirit, and no time to check them all)
I didn't find anything parallel to that for gcc.

On Mon, Jan 11, 2010 at 11:54 PM, Elazar Leibovich <elazarl at gmail.com>wrote:

> We have a big legacy embedded code we need to maintain. Often, we wish to
> run some functions of the code on the PC with injected input, to test them
> or to test changes we've done to them without loading the code to the device
> it should run on.
> The code is written with C.
> Obviously, this is not an easy task, it is more difficult because, the code
> is bug ridden, and many times it works by accident (for example, a NULL
> pointer added a constant and then derefeced, this worked because the memory
> address was legal).
> Since the code is big, our strategy is: compile just the parts you need,
> debug it enough so that it would run on the PC, and keep the changes.
> Hopefully, after enough time, all (or most) of the code would be runnable on
> a PC.
> We use gcc+gdb to compile and debug the code. In Visual Studio's
> cl.exe there are some security checks<http://msdn.microsoft.com/en-us/library/aa289171(VS.71).aspx>at run time. This can really assist debugging. For example knowing when an
> unintialized variable was used can save you alot of frustration when trying
> to figure out why you're getting a wrong numberic results.
> My questions are:
> 1) Are there parallel (or better) runtime security checks for gcc/gdb? I
> found the -fstack-protection stack canary switch, but are there more of this
> type?
> 2) What other tools are there which offer similar protection? Valgrind of
> course is the first thing that comes to my mind, but I'll be glad to hear
> any more ideas.
> For example, I would love to be able to get a warning whenever a pointer is
> dereferenced twice, where the first time the pointer points at the memory
> address of variable x, and the second time it points to variable y. That way
> I'll get a warning for the following bug:
> int x[3] = {1,2,3};int y[3] = {4,5,6};
> int *p = x;
> for (int i=0;i<=3;i++,p++) (*p) = (*p)++; // note the <=
> 3) We use win32 for regular development, so if anyone knows what is the
> support for such tests in cygwin/mingw, I'll be glad to hear about it.
>
> Thanks
> Elazar Leibovich
>
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