3.2.99-rc1 review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
commit f658f17b5e0e339935dca23e77e0f3cad591926b upstream.
The usb-audio driver may trigger an out-of-bound access at parsing a malformed selector unit, as it checks the header length only after evaluating bNrInPins field, which can be already above the given length. Fix it by adding the length check beforehand.
Fixes: 99fc86450c43 ("ALSA: usb-mixer: parse descriptors with structs") Signed-off-by: Takashi Iwai tiwai@suse.de [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- sound/usb/mixer.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1845,7 +1845,8 @@ static int parse_audio_selector_unit(str const struct usbmix_name_map *map; char **namelist;
- if (!desc->bNrInPins || desc->bLength < 5 + desc->bNrInPins) { + if (desc->bLength < 5 || !desc->bNrInPins || + desc->bLength < 5 + desc->bNrInPins) { snd_printk(KERN_ERR "invalid SELECTOR UNIT descriptor %d\n", unitid); return -EINVAL; }