Morning,
this question on secure memcpy for C over on security.stackexchange.com and originally on Stackoverflow has caused a bit of a religious war (which is why the stackoverflow one was pulled) but the original poster really wants to get a rational answer on safe and unsafe commands for non MS C.
So I thought I'd pop it up here as this is one of the few places I can think of that doesn't really do religious warring or irrational argument.
for those who don't use stackexchange, the original question is here:
Buffer overflows are nothing new. And yet they still appear often, especially in native (i.e. not managed) code...
Part of the root cause, is usage of "unsafe" functions, including C++ staples such as memcpy, strcpy, strncpy, and more. These functions are considered unsafe since they directly handle unconstrained buffers, and without intensive, careful bounds checkings will typically directly overflow any target buffers.
Microsoft via SDL has banned use of those "unsafe" functions, and provides replacement functions for C++ - e.g. strcpy_s for strcpy, memcpy_s for memcpy, etc (depending on environment). Latest versions of Visual Studio will even let you do this automatically...
But what about "pure" C (i.e. not C++)?
And especially, what about non-MS platforms - including Linux and even non-VS compilers on windows...
Does anyone have safer replacement functions for these? Any recommended workarounds (besides simply doing more bounds checking...)?
Or are we all doomed to continue repeating our use of memcpy?
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