strongSwan

https://github.com/strongswan/strongswan/blob/master/src/libstrongswan/plugins/random/random_rng.c

If 'read' returns -1, then 'got' becomes -1. done will be SIZE_T_MAX (because it is unsigned). The loop will exit and return TRUE without ever allocating random.

For reference, the code:

METHOD(rng_t, get_bytes, bool,
    private_random_rng_t *this, size_t bytes, u_int8_t *buffer)
{
    size_t done;
    ssize_t got;

    done = 0;

    while (done < bytes)
    {
        got = read(this->fd, buffer + done, bytes - done);
        if (got <= 0)
        {
            DBG1(DBG_LIB, "reading from random FD %d failed: %s, retrying...",
                 this->fd, strerror(errno));
            sleep(1);
        }
        done += got;
    }
    return TRUE;
}