4.4-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
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: 79f920fbff56 ("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: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- sound/usb/clock.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/sound/usb/clock.c +++ b/sound/usb/clock.c @@ -43,7 +43,7 @@ static struct uac_clock_source_descripto 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_descrip 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_descr 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; }