`uac_mixer_unit_get_channels` calls `uac_mixer_unit_bmControls`
to get pointer to bmControls field. The current implementation of
`uac_mixer_unit_get_channels` does properly check the size of
uac_mixer_unit_descriptor descriptor and may allow OOB access
in `uac_mixer_unit_bmControls`.
Reported-by: Hui Peng <benquike@xxxxxxxxx>
Reported-by: Mathias Payer <mathias.payer@xxxxxxxxxxxxx>
Signed-off-by: Hui Peng <benquike@xxxxxxxxx>
---
sound/usb/mixer.c | 25 ++++++++++++++++++-------
1 file changed, 18 insertions(+), 7 deletions(-)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index b5927c3d5bc0..00e6274a63c3 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -738,28 +738,39 @@ static int get_cluster_channels_v3(struct mixer_build *state, unsigned int clust
static int uac_mixer_unit_get_channels(struct mixer_build *state,
struct uac_mixer_unit_descriptor *desc)
{
- int mu_channels;
+ int mu_channels = 0;
void *c;
- if (desc->bLength < sizeof(*desc))
- return -EINVAL;
if (!desc->bNrInPins)
return -EINVAL;
- if (desc->bLength < sizeof(*desc) + desc->bNrInPins)
- return -EINVAL;
switch (state->mixer->protocol) {
case UAC_VERSION_1:
+ // limit derived from uac_mixer_unit_bmControls
+ if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 4)
+ return 0;
+
+ mu_channels = uac_mixer_unit_bNrChannels(desc);
+ break;
+
case UAC_VERSION_2:
- default:
- if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 1)
+ // limit derived from uac_mixer_unit_bmControls
+ if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 6)
return 0; /* no bmControls -> skip */
+
mu_channels = uac_mixer_unit_bNrChannels(desc);
break;
case UAC_VERSION_3:
+ // limit derived from uac_mixer_unit_bmControls
+ if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 2)
+ return 0; /* no bmControls -> skip */
+
mu_channels = get_cluster_channels_v3(state,
uac3_mixer_unit_wClusterDescrID(desc));
break;
+
+ default:
+ break;
}
if (!mu_channels)
--
2.22.1
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