| From | Greg Kroah-Hartman <> | Subject | [ 44/89] ALSA: usb-audio: fix invalid length check for RME and other UAC 2 devices | Date | Fri, 1 Feb 2013 14:07:59 +0100 |
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3.7-stable review patch. If anyone has any objections, please let me know.
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From: Clemens Ladisch <clemens@ladisch.de>
commit d56268fb108c7c21e19933588ca4d94652585183 upstream.
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 Babyface or Fireface UCX.
Reported-by: Florian Hanisch <fhanisch@uni-potsdam.de> Tested-by: Matthew Robbetts <wingfeathera@gmail.com> Tested-by: Michael Beer <beerml@sigma6audio.de> Cc: Daniel Mack <daniel@caiaq.de> Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- sound/usb/mixer.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
--- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1259,16 +1259,23 @@ static int parse_audio_feature_unit(stru } 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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