static void virtqueue_map_iovec(struct iovec *sg, hwaddr *addr,
                                unsigned int *num_sg, unsigned int max_size,
                                int is_write)
{
    unsigned int i;
    hwaddr len;

    /* Note: this function MUST validate input, some callers
     * are passing in num_sg values received over the network.
     */
    /* TODO: teach all callers that this can fail, and return failure instead
     * of asserting here.
     * When we do, we might be able to re-enable NDEBUG below.
     */
#ifdef NDEBUG
#error building with NDEBUG is not supported
#endif
    assert(*num_sg <= max_size);

    for (i = 0; i < *num_sg; i++) {
        len = sg[i].iov_len;
        sg[i].iov_base = cpu_physical_memory_map(addr[i], &len, is_write);
        if (!sg[i].iov_base) {
            error_report("virtio: error trying to map MMIO memory");
            exit(1);
        }
        if (len != sg[i].iov_len) {
            error_report("virtio: unexpected memory split");
            exit(1);
        }
    }
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.