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authorHui Peng <benquike@gmail.com>2019-08-13 22:34:04 -0400
committerTakashi Iwai <tiwai@suse.de>2019-08-14 20:05:56 +0200
commitdaac07156b330b18eb5071aec4b3ddca1c377f2c (patch)
treecca841f4517aff5cca1d5edbb49b947cdcf9a780
parent871b9066027702e6e6589da0e1edd3b7dede7205 (diff)
download96b-common-daac07156b330b18eb5071aec4b3ddca1c377f2c.tar.gz
ALSA: usb-audio: 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. 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>
-rw-r--r--sound/usb/mixer.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 7498b5191b68..ea487378be17 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -744,6 +744,8 @@ 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: