From: Hui Peng <[email protected]>
commit daac07156b330b18eb5071aec4b3ddca1c377f2c upstream.
The `uac_mixer_unit_descriptor` shown as below is read from the
device side. In `parse_audio_mixer_unit`, `baSourceID` field is
accessed from index 0 to `bNrInPins` - 1, the current implementation
assumes that descriptor is always valid (the length of descriptor
is no shorter than 5 + `bNrInPins`). If a descriptor read from
the device side is invalid, it may trigger out-of-bound memory
access.
```
struct uac_mixer_unit_descriptor {
__u8 bLength;
__u8 bDescriptorType;
__u8 bDescriptorSubtype;
__u8 bUnitID;
__u8 bNrInPins;
__u8 baSourceID[];
}
```
This patch fixes the bug by add a sanity check on the length of
the descriptor.
Reported-by: Hui Peng <[email protected]>
Reported-by: Mathias Payer <[email protected]>
Cc: <[email protected]>
Signed-off-by: Hui Peng <[email protected]>
Signed-off-by: Takashi Iwai <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
sound/usb/mixer.c | 1 +
1 file changed, 1 insertion(+)
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1719,6 +1719,7 @@ static int parse_audio_mixer_unit(struct
int pin, ich, err;
if (desc->bLength < 11 || !(input_pins = desc->bNrInPins) ||
+ desc->bLength < sizeof(*desc) + desc->bNrInPins ||
!(num_outs = uac_mixer_unit_bNrChannels(desc))) {
usb_audio_err(state->chip,
"invalid MIXER UNIT descriptor %d\n",
