malloc/beware_overflow/beware_overflow.c


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#include "beware_overflow.h"

void *beware_overflow(void *ptr, size_t nmemb, size_t size)
{
    size_t res;
    if (__builtin_umull_overflow(nmemb, size, &res))
        return NULL;
    char *r = ptr;
    return r + res;
}