iperf_new_stream(struct iperf_test *test, int s)
{
    int i;
    struct iperf_stream *sp;
    char template[] = "/tmp/iperf3.XXXXXX";

    h_errno = 0;

    sp = (struct iperf_stream *) malloc(sizeof(struct iperf_stream));
    if (!sp) {
        i_errno = IECREATESTREAM;
        return NULL;
    }

    memset(sp, 0, sizeof(struct iperf_stream));

    sp->test = test;
    sp->settings = test->settings;
    sp->result = (struct iperf_stream_result *) malloc(sizeof(struct iperf_stream_result));
    if (!sp->result) {
        free(sp);
        i_errno = IECREATESTREAM;
        return NULL;
    }

    memset(sp->result, 0, sizeof(struct iperf_stream_result));
    TAILQ_INIT(&sp->result->interval_results);
    
    /* Create and randomize the buffer */
    sp->buffer_fd = mkstemp(template);
    if (sp->buffer_fd == -1) {
        i_errno = IECREATESTREAM;
        free(sp->result);
        free(sp);
        return NULL;
    }
    if (unlink(template) < 0) {
        i_errno = IECREATESTREAM;
        free(sp->result);
        free(sp);
        return NULL;
    }
    if (ftruncate(sp->buffer_fd, test->settings->blksize) < 0) {
        i_errno = IECREATESTREAM;
        free(sp->result);
        free(sp);
        return NULL;
    }
    sp->buffer = (char *) mmap(NULL, test->settings->blksize, PROT_READ|PROT_WRITE, MAP_PRIVATE, sp->buffer_fd, 0);
    if (sp->buffer == MAP_FAILED) {
        i_errno = IECREATESTREAM;
        free(sp->result);
        free(sp);
        return NULL;
    }
    srandom(time(NULL));
    for (i = 0; i < test->settings->blksize; ++i)
        sp->buffer[i] = random();

    /* Set socket */
    sp->socket = s;

    sp->snd = test->protocol->send;
    sp->rcv = test->protocol->recv;

    if (test->diskfile_name != (char*) 0) {
	sp->diskfile_fd = open(test->diskfile_name, test->sender ? O_RDONLY : (O_WRONLY|O_CREAT|O_TRUNC), S_IRUSR|S_IWUSR);
	if (sp->diskfile_fd == -1) {
	    i_errno = IEFILE;
            munmap(sp->buffer, sp->test->settings->blksize);
            free(sp->result);
            free(sp);
	    return NULL;
	}
        sp->snd2 = sp->snd;
	sp->snd = diskfile_send;
	sp->rcv2 = sp->rcv;
	sp->rcv = diskfile_recv;
    } else
        sp->diskfile_fd = -1;

    /* Initialize stream */
    if (iperf_init_stream(sp, test) < 0) {
        close(sp->buffer_fd);
        munmap(sp->buffer, sp->test->settings->blksize);
        free(sp->result);
        free(sp);
        return NULL;
    }
    iperf_add_stream(test, sp);

    return sp;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.