From: Hui Peng benquike@gmail.com
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 benquike@gmail.com Reported-by: Mathias Payer mathias.payer@nebelwelt.net Cc: stable@vger.kernel.org Signed-off-by: Hui Peng benquike@gmail.com Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- sound/usb/mixer.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 2051a64fa2904..b5927c3d5bc0b 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -745,6 +745,8 @@ static int uac_mixer_unit_get_channels(struct mixer_build *state, return -EINVAL; if (!desc->bNrInPins) return -EINVAL; + if (desc->bLength < sizeof(*desc) + desc->bNrInPins) + return -EINVAL;
switch (state->mixer->protocol) { case UAC_VERSION_1: