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| author | Cássio Gabriel <cassiogabrielcontato@gmail.com> | 2026-05-07 11:28:30 -0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2026-05-15 11:21:20 +0200 |
| commit | c77a6cbb36ff8cbc1f084d94f8dcda5250935271 (patch) | |
| tree | 8589a63bd9f37b4a1655b2474d986521f588d550 /sound | |
| parent | 0cf821727205109ff2119d2bbd45fef8239f7e2c (diff) | |
| download | linux-next-history-c77a6cbb36ff8cbc1f084d94f8dcda5250935271.tar.gz | |
ALSA: virtio: Validate control metadata from the device
virtio-snd control handling trusts the device-provided control type and
value count returned by the device.
That metadata is then used directly to index g_v2a_type_map[] in
virtsnd_kctl_info(), and to size loops and memcpy() operations in
virtsnd_kctl_get() and virtsnd_kctl_put() against fixed-size
virtio_snd_ctl_value and snd_ctl_elem_value arrays.
A buggy or malicious device can therefore trigger out-of-bounds access by
advertising an invalid control type or an oversized value count.
Validate control type and count once in virtsnd_kctl_parse_cfg(), before
querying enumerated items or exposing the control to ALSA.
Fixes: d6568e3de42d ("ALSA: virtio: add support for audio controls")
Cc: stable@vger.kernel.org
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260507-alsa-virtio-validate-kctl-info-v1-1-7404fb12ec37@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/virtio/virtio_kctl.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/sound/virtio/virtio_kctl.c b/sound/virtio/virtio_kctl.c index ffb903d56297a..45f7b6a5b3080 100644 --- a/sound/virtio/virtio_kctl.c +++ b/sound/virtio/virtio_kctl.c @@ -18,6 +18,21 @@ static const snd_ctl_elem_type_t g_v2a_type_map[] = { [VIRTIO_SND_CTL_TYPE_IEC958] = SNDRV_CTL_ELEM_TYPE_IEC958 }; +/* Map for converting VirtIO types to maximum value counts. */ +static const unsigned int g_v2a_count_map[] = { + [VIRTIO_SND_CTL_TYPE_BOOLEAN] = + ARRAY_SIZE(((struct virtio_snd_ctl_value *)0)->value.integer), + [VIRTIO_SND_CTL_TYPE_INTEGER] = + ARRAY_SIZE(((struct virtio_snd_ctl_value *)0)->value.integer), + [VIRTIO_SND_CTL_TYPE_INTEGER64] = + ARRAY_SIZE(((struct virtio_snd_ctl_value *)0)->value.integer64), + [VIRTIO_SND_CTL_TYPE_ENUMERATED] = + ARRAY_SIZE(((struct virtio_snd_ctl_value *)0)->value.enumerated), + [VIRTIO_SND_CTL_TYPE_BYTES] = + ARRAY_SIZE(((struct virtio_snd_ctl_value *)0)->value.bytes), + [VIRTIO_SND_CTL_TYPE_IEC958] = 1 +}; + /* Map for converting VirtIO access rights to ALSA access rights. */ static const unsigned int g_v2a_access_map[] = { [VIRTIO_SND_CTL_ACCESS_READ] = SNDRV_CTL_ELEM_ACCESS_READ, @@ -36,6 +51,37 @@ static const unsigned int g_v2a_mask_map[] = { [VIRTIO_SND_CTL_EVT_MASK_TLV] = SNDRV_CTL_EVENT_MASK_TLV }; +static int virtsnd_kctl_validate_info(struct virtio_snd *snd, u32 cid, + struct virtio_snd_ctl_info *kinfo) +{ + struct virtio_device *vdev = snd->vdev; + unsigned int type = le32_to_cpu(kinfo->type); + unsigned int count = le32_to_cpu(kinfo->count); + + if (type >= ARRAY_SIZE(g_v2a_type_map)) { + dev_err(&vdev->dev, "control #%u: unknown type %u\n", + cid, type); + return -EINVAL; + } + + if (count > g_v2a_count_map[type] || + (type == VIRTIO_SND_CTL_TYPE_IEC958 && count != 1)) { + dev_err(&vdev->dev, "control #%u: invalid count %u for type %u\n", + cid, count, type); + return -EINVAL; + } + + if (type == VIRTIO_SND_CTL_TYPE_ENUMERATED && + !le32_to_cpu(kinfo->value.enumerated.items)) { + dev_err(&vdev->dev, + "control #%u: no items for enumerated control\n", + cid); + return -EINVAL; + } + + return 0; +} + /** * virtsnd_kctl_info() - Returns information about the control. * @kcontrol: ALSA control element. @@ -385,6 +431,10 @@ int virtsnd_kctl_parse_cfg(struct virtio_snd *snd) struct virtio_snd_ctl_info *kinfo = &snd->kctl_infos[i]; unsigned int type = le32_to_cpu(kinfo->type); + rc = virtsnd_kctl_validate_info(snd, i, kinfo); + if (rc) + return rc; + if (type == VIRTIO_SND_CTL_TYPE_ENUMERATED) { rc = virtsnd_kctl_get_enum_items(snd, i); if (rc) |