Runtime security/memory checks for gcc/gdb

[guy keren]

valgrind should be your first tool for the task. use it and fix all the 
errors it reports.

what valgrind does not catch, are:

1. corruptions with global variables.
2. many corruptions on the stack.

but it catches a lot of other errors.

i use no other tools at work - except for as many of gcc's warnings as 
possible (and the code is compiled with '-Werror' - so we must fix all 
warnings, one way or another).

--guy

Elazar Leibovich 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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