hw/audio/virtio-sound: fix heap buffer overflow

Currently, the guest may write to the device configuration space,
whereas the virtio sound device specification in chapter 5.14.4
clearly states that the fields in the device configuration space
are driver-read-only.

Remove the set_config function from the virtio_snd class.

This also prevents a heap buffer overflow. See QEMU issue #2296.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2296
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Message-Id: <20240901130112.8242-1-vr_qemu@t-online.de>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/audio/trace-events b/hw/audio/trace-events
index b1870ff224b3c1677d2ec976e981b3495ec3eb9d..b8ef5727678f6dcf8c4d1341f38ea519b946a3f5 100644 (file)
--- a/hw/audio/trace-events
+++ b/hw/audio/trace-events
@@ -41,7 +41,6 @@ asc_update_irq(int irq, int a, int b) "set IRQ to %d (A: 0x%x B: 0x%x)"
 
 #virtio-snd.c
 virtio_snd_get_config(void *vdev, uint32_t jacks, uint32_t streams, uint32_t chmaps) "snd %p: get_config jacks=%"PRIu32" streams=%"PRIu32" chmaps=%"PRIu32""
-virtio_snd_set_config(void *vdev, uint32_t jacks, uint32_t new_jacks, uint32_t streams, uint32_t new_streams, uint32_t chmaps, uint32_t new_chmaps) "snd %p: set_config jacks from %"PRIu32"->%"PRIu32", streams from %"PRIu32"->%"PRIu32", chmaps from %"PRIu32"->%"PRIu32
 virtio_snd_get_features(void *vdev, uint64_t features) "snd %p: get_features 0x%"PRIx64
 virtio_snd_vm_state_running(void) "vm state running"
 virtio_snd_vm_state_stopped(void) "vm state stopped"

diff --git a/hw/audio/virtio-snd.c b/hw/audio/virtio-snd.c
index d1cf5eb445d71bab4cdf03521c2aa1fc2ac92882..69838181dd1cad3ec01d3c8e54b5df0c1d6e185c 100644 (file)
--- a/hw/audio/virtio-snd.c
+++ b/hw/audio/virtio-snd.c
@@ -107,29 +107,6 @@ virtio_snd_get_config(VirtIODevice *vdev, uint8_t *config)
 
 }
 
-static void
-virtio_snd_set_config(VirtIODevice *vdev, const uint8_t *config)
-{
-    VirtIOSound *s = VIRTIO_SND(vdev);
-    const virtio_snd_config *sndconfig =
-        (const virtio_snd_config *)config;
-
-
-   trace_virtio_snd_set_config(vdev,
-                               s->snd_conf.jacks,
-                               sndconfig->jacks,
-                               s->snd_conf.streams,
-                               sndconfig->streams,
-                               s->snd_conf.chmaps,
-                               sndconfig->chmaps);
-
-    memcpy(&s->snd_conf, sndconfig, sizeof(virtio_snd_config));
-    le32_to_cpus(&s->snd_conf.jacks);
-    le32_to_cpus(&s->snd_conf.streams);
-    le32_to_cpus(&s->snd_conf.chmaps);
-
-}
-
 static void
 virtio_snd_pcm_buffer_free(VirtIOSoundPCMBuffer *buffer)
 {
@@ -1400,7 +1377,6 @@ static void virtio_snd_class_init(ObjectClass *klass, void *data)
     vdc->realize = virtio_snd_realize;
     vdc->unrealize = virtio_snd_unrealize;
     vdc->get_config = virtio_snd_get_config;
-    vdc->set_config = virtio_snd_set_config;
     vdc->get_features = get_features;
     vdc->reset = virtio_snd_reset;
     vdc->legacy_features = 0;