Merge "crasher: heap-buffer-overflow, invalid-free, and use-after-free." into main

#pragma clang diagnostic push

#pragma clang diagnostic ignored "-Wfree-nonheap-object"

noinline void abuse_heap() {

noinline void invalid_free() {

    char buf[16];

    free(buf); // GCC is smart enough to warn about this, but we're doing it deliberately.

    free(buf); // The compiler is smart enough to warn about this, but we're doing it deliberately.

}

#pragma clang diagnostic pop

noinline void heap_buffer_overflow() {

    volatile char* p = reinterpret_cast<volatile char*>(malloc(32));

    p[32] = p[32];

}

noinline void use_after_free() {

    void* allocation = malloc(32);

    volatile char* p = reinterpret_cast<volatile char*>(allocation);

    free(allocation);

    p[0] = p[0];

}

noinline void leak() {

    while (true) {

        void* mapping =

    fprintf(stderr, "  stack-overflow        recurse until the stack overflows\n");

    fprintf(stderr, "  nostack               crash with a NULL stack pointer\n");

    fprintf(stderr, "\n");

    fprintf(stderr, "  heap-usage            cause a libc abort by abusing a heap function\n");

    fprintf(stderr, "  heap-buffer-overflow  write past the end of a heap allocation\n");

    fprintf(stderr, "  invalid-free          pass a non-heap pointer to free()\n");

    fprintf(stderr, "  use-after-free        write to a buffer after free()\n");

    fprintf(stderr, "\n");

    fprintf(stderr, "  call-null             cause a crash by calling through a nullptr\n");

    fprintf(stderr, "  leak                  leak memory until we get OOM-killed\n");

    fprintf(stderr, "\n");

      return strlen_null();

    } else if (!strcasecmp(arg, "pthread_join-NULL")) {

      return pthread_join(0, nullptr);

    } else if (!strcasecmp(arg, "heap-usage")) {

      abuse_heap();

    } else if (!strcasecmp(arg, "heap-buffer-overflow")) {

      heap_buffer_overflow();

    } else if (!strcasecmp(arg, "invalid-free")) {

      invalid_free();

    } else if (!strcasecmp(arg, "use-after-free")) {

      use_after_free();

    } else if (!strcasecmp(arg, "leak")) {

      leak();

    } else if (!strcasecmp(arg, "SIGSEGV-unmapped")) {

        return usage();

    }

    fprintf(stderr, "%s: exiting normally!\n", getprogname());

    fprintf(stderr, "%s: exiting normally (which is unexpected)!\n", getprogname());

    return EXIT_SUCCESS;

}