Matthew Robbetts wrote:
> Is this bug fixed upstream at this point?
This patch is still untested:
--8<----------------------------------------------------------------->8--
ALSA: usb-audio: fix invalid length check for RME and other UAC 2 devices
Commit 23caaf19b11e (ALSA: usb-mixer: Add support for Audio Class v2.0)
forgot to adjust the length check for UAC 2.0 feature unit descriptors.
This would make the code abort on encountering a feature unit without
per-channel controls, and thus prevented the driver to work with any
device having such a unit, such as the RME Fireface UCX.
Reported-by: Florian Hanisch <fhanisch@xxxxxxxxxxxxxx>
Cc: Daniel Mack <daniel@xxxxxxxx>
Cc: 2.6.35+ <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Clemens Ladisch <clemens@xxxxxxxxxx>
---
sound/usb/mixer.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 298070e..41e8bfb 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1259,16 +1259,23 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
}
channels = (hdr->bLength - 7) / csize - 1;
bmaControls = hdr->bmaControls;
+ if (hdr->bLength < 7 + csize) {
+ snd_printk(KERN_ERR "usbaudio: unit %u: "
+ "invalid UAC_FEATURE_UNIT descriptor\n",
+ unitid);
+ return -EINVAL;
+ }
} else {
struct uac2_feature_unit_descriptor *ftr = _ftr;
csize = 4;
channels = (hdr->bLength - 6) / 4 - 1;
bmaControls = ftr->bmaControls;
- }
-
- if (hdr->bLength < 7 || !csize || hdr->bLength < 7 + csize) {
- snd_printk(KERN_ERR "usbaudio: unit %u: invalid UAC_FEATURE_UNIT descriptor\n", unitid);
- return -EINVAL;
+ if (hdr->bLength < 6 + csize) {
+ snd_printk(KERN_ERR "usbaudio: unit %u: "
+ "invalid UAC_FEATURE_UNIT descriptor\n",
+ unitid);
+ return -EINVAL;
+ }
}
/* parse the source unit */
------------------------------------------------------------------------------
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