The attached file is the KASAN report.
On Tue, Aug 13, 2019 at 10:37 PM Hui Peng benquike@gmail.com wrote:
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.
Signed-off-by: Hui Peng benquike@gmail.com Reported-by: Hui Peng benquike@gmail.com Reported-by: Mathias Payer mathias.payer@nebelwelt.net
sound/usb/mixer.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 7498b5191b68..38202ce67237 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -2091,6 +2091,15 @@ static int parse_audio_mixer_unit(struct mixer_build *state, int unitid, struct usb_audio_term iterm; int input_pins, num_ins, num_outs; int pin, ich, err;
int desc_len = (int) ((unsigned long) state->buffer +state->buflen - (unsigned long) raw_desc);if (desc_len < sizeof(*desc) + desc->bNrInPins) {usb_audio_err(state->chip,"descriptor %d too short\n",unitid);return -EINVAL;} err = uac_mixer_unit_get_channels(state, desc); if (err < 0) {-- 2.22.1