Re: [PULL 2/3] hw/audio/virtio-snd: fix invalid param check

[Volker Rümelin]

Cc: qemu-stable@nongnu.org

Without this patch, the virtio-sound device will not work in the next
QEMU stable-8.2 and stable-9.0 versions.

With best regards,
Volker

> From: Volker Rümelin <vr_qemu@t-online.de>
>
> Commit 9b6083465f ("virtio-snd: check for invalid param shift
> operands") tries to prevent invalid parameters specified by the
> guest. However, the code is not correct.
>
> Change the code so that the parameters format and rate, which are
> a bit numbers, are compared with the bit size of the data type.
>
> Fixes: 9b6083465f ("virtio-snd: check for invalid param shift operands")
> Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
> Message-Id: <20240802071805.7123-1-vr_qemu@t-online.de>
> Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  hw/audio/virtio-snd.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/audio/virtio-snd.c b/hw/audio/virtio-snd.c
> index e5196aa4bb..d1cf5eb445 100644
> --- a/hw/audio/virtio-snd.c
> +++ b/hw/audio/virtio-snd.c
> @@ -282,12 +282,12 @@ uint32_t virtio_snd_set_pcm_params(VirtIOSound *s,
>          error_report("Number of channels is not supported.");
>          return cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
>      }
> -    if (BIT(params->format) > sizeof(supported_formats) ||
> +    if (params->format >= sizeof(supported_formats) * BITS_PER_BYTE ||
>          !(supported_formats & BIT(params->format))) {
>          error_report("Stream format is not supported.");
>          return cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
>      }
> -    if (BIT(params->rate) > sizeof(supported_rates) ||
> +    if (params->rate >= sizeof(supported_rates) * BITS_PER_BYTE ||
>          !(supported_rates & BIT(params->rate))) {
>          error_report("Stream rate is not supported.");
>          return cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);