[PATCH v1] virtio-snd: check for invalid param shift operands

[PATCH v1] virtio-snd: check for invalid param shift operands

[Manos Pitsidianakis]

When setting the parameters of a PCM stream, we compute the bit flag
with the format and rate values as shift operand to check if they are
set in supported_formats and supported_rates.

If the guest provides a format/rate value which when shifting 1 results
in a value bigger than the number of bits in
supported_formats/supported_rates, we must report an error.

Previously, this ended up triggering the not reached assertions later
when converting to internal QEMU values.

Reported-by: Zheyu Ma <zheyuma97@gmail.com>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2416
Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
---
 hw/audio/virtio-snd.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/audio/virtio-snd.c b/hw/audio/virtio-snd.c
index 5993f4f040..98a7ef5719 100644
--- a/hw/audio/virtio-snd.c
+++ b/hw/audio/virtio-snd.c
@@ -282,11 +282,13 @@ 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 (!(supported_formats & BIT(params->format))) {
+    if (BIT(params->format) > sizeof(supported_formats) ||
+        !(supported_formats & BIT(params->format))) {
         error_report("Stream format is not supported.");
         return cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
     }
-    if (!(supported_rates & BIT(params->rate))) {
+    if (BIT(params->rate) > sizeof(supported_rates) ||
+        !(supported_rates & BIT(params->rate))) {
         error_report("Stream rate is not supported.");
         return cpu_to_le32(VIRTIO_SND_S_NOT_SUPP);
     }

base-commit: 59084feb256c617063e0dbe7e64821ae8852d7cf
-- 
γαῖα πυρί μιχθήτω

Re: [PATCH v1] virtio-snd: check for invalid param shift operands

[Philippe Mathieu-Daudé]

On 11/7/24 09:38, Manos Pitsidianakis wrote:
> When setting the parameters of a PCM stream, we compute the bit flag
> with the format and rate values as shift operand to check if they are
> set in supported_formats and supported_rates.
> 
> If the guest provides a format/rate value which when shifting 1 results
> in a value bigger than the number of bits in
> supported_formats/supported_rates, we must report an error.
> 
> Previously, this ended up triggering the not reached assertions later
> when converting to internal QEMU values.
> 
> Reported-by: Zheyu Ma <zheyuma97@gmail.com>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2416
> Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
> ---
>   hw/audio/virtio-snd.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>