diff options
| author | Hui Peng <benquike@gmail.com> | 2019-08-13 22:34:04 -0400 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2019-08-14 20:05:56 +0200 |
| commit | daac07156b330b18eb5071aec4b3ddca1c377f2c (patch) | |
| tree | cca841f4517aff5cca1d5edbb49b947cdcf9a780 /sound/usb | |
| parent | 871b9066027702e6e6589da0e1edd3b7dede7205 (diff) | |
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>
Diffstat (limited to 'sound/usb')
| -rw-r--r-- | sound/usb/mixer.c | 2 |
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: |