Re: [PATCH v2 1/1] s390x/s390-virtio-ccw: fix off-by-one in loadparm getter

[Peter Maydell]

On Thu, 30 Jul 2020 at 14:02, Halil Pasic <pasic@linux.ibm.com> wrote:
>
> As pointed out by Peter, g_memdup(ms->loadparm, sizeof(ms->loadparm) + 1)
> reads one past of the end of ms->loadparm, so g_memdup() can not be used
> here.
>
> Let's use g_strndup instead!
>
> Fixes: d664548328 ("s390x/s390-virtio-ccw: fix loadparm property getter")
> Fixes: Coverity CID 1431058
> Reported-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
> ---
>  hw/s390x/s390-virtio-ccw.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index 403d30e13b..e72c61d2ea 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -701,12 +701,9 @@ bool hpage_1m_allowed(void)
>  static char *machine_get_loadparm(Object *obj, Error **errp)
>  {
>      S390CcwMachineState *ms = S390_CCW_MACHINE(obj);
> -    char *loadparm_str;
>
>      /* make a NUL-terminated string */
> -    loadparm_str = g_memdup(ms->loadparm, sizeof(ms->loadparm) + 1);
> -    loadparm_str[sizeof(ms->loadparm)] = 0;
> -    return loadparm_str;
> +    return g_strndup((char *) ms->loadparm, sizeof(ms->loadparm));
>  }

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM