Problem - Kevin Tafuro

If you prefer to give programmers the chance to handle the problem, you could
throw an exception. In such a case, we recommend using the standard errno values
as exception codes and using positive integers above 256 for application-specific
exceptions.
#include
#include
#include
#define EXCEPTION_OUT_OF_MEMORY (ENOMEM)
void *my_malloc(size_t sz) {
void *res = malloc(sz);
/* We pass the amount of memory requested as extra data. */
if (!res) RAISE(EXCEPTION_OUT_OF_MEMORY, (void *)sz);
return res;
}
See Also
XXL exception handling library for C: http://www.zork.org/xxl/
13.2 Erasing Data from Memory Securely
Problem
You want to minimize the exposure of data such as passwords and cryptographic
keys to local attacks.
Solution
You can only guarantee that memory is erased if you declare it to be volatile at the
point where you write over it. In addition, you must not use an operation such as
realloc( ) that may silently move sensitive data. In any event, you might also need
to worry about data being swapped to disk; see Recipe 13.3.
Discussion
Securely erasing data from memory is a lot easier in C and C++ than it is in languages
where all memory is managed behind the programmer’s back. There are still
some nonobvious pitfalls, however.
One pitfall, particularly in C++, is that some API functions may silently move data
behind the programmer’s back, leaving behind a copy of the data in a different part
of memory. The most prominent example in the C realm is realloc( ), which will
sometimes move a piece of memory, updating the programmer’s pointer. Yet the old
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