ALSA: usb-audio: Add sanity checks in v2 clock parsers

commit 0a62d6c966956d77397c32836a5bbfe3af786fc1 upstream.

The helper functions to parse and look for the clock source, selector
and multiplier unit may return the descriptor with a too short length
than required, while there is no sanity check in the caller side.
Add some sanity checks in the parsers, at least, to guarantee the
given descriptor size, for avoiding the potential crashes.

Fixes: 79f920fbff ("ALSA: usb-audio: parse clock topology of UAC2 devices")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This commit is contained in:
Takashi Iwai 2017-11-21 17:28:06 +01:00 committed by syphyr
parent c1efafdaa4
commit da5a9a34d0
1 changed files with 6 additions and 3 deletions

View File

@ -43,7 +43,7 @@ static struct uac_clock_source_descriptor *
while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
ctrl_iface->extralen,
cs, UAC2_CLOCK_SOURCE))) {
if (cs->bClockID == clock_id)
if (cs->bLength >= sizeof(*cs) && cs->bClockID == clock_id)
return cs;
}
@ -59,8 +59,11 @@ static struct uac_clock_selector_descriptor *
while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
ctrl_iface->extralen,
cs, UAC2_CLOCK_SELECTOR))) {
if (cs->bClockID == clock_id)
if (cs->bLength >= sizeof(*cs) && cs->bClockID == clock_id) {
if (cs->bLength < 5 + cs->bNrInPins)
return NULL;
return cs;
}
}
return NULL;
@ -75,7 +78,7 @@ static struct uac_clock_multiplier_descriptor *
while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
ctrl_iface->extralen,
cs, UAC2_CLOCK_MULTIPLIER))) {
if (cs->bClockID == clock_id)
if (cs->bLength >= sizeof(*cs) && cs->bClockID == clock_id)
return cs;
}