>From 09942398a53bbe730264b782673890d4a54068d0 Mon Sep 17 00:00:00 2001 From: Hui Peng Date: Fri, 30 Aug 2019 16:11:00 -0400 Subject: [PATCH 1/2] Fix an OOB bug in parse_audio_mixer_unit 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. CVE: CVE-2019-15117 Reported-by: Hui Peng Reported-by: Mathias Payer Signed-off-by: Hui Peng --- sound/usb/mixer.c | 1 + 1 file changed, 1 insertion(+) diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 1f7eb3816cd7..10ddec76f906 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1628,6 +1628,7 @@ static int parse_audio_mixer_unit(struct mixer_build *state, int unitid, 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", -- 2.17.1