From 199615725dd969a800154f48f739ea83b3c86eec Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Wed, 18 Jun 2014 13:32:34 +0200 Subject: [PATCH] ALSA: control: Handle numid overflow Each control gets automatically assigned its numids when the control is created. The allocation is done by incrementing the numid by the amount of allocated numids per allocation. This means that excessive creation and destruction of controls (e.g. via SNDRV_CTL_IOCTL_ELEM_ADD/REMOVE) can cause the id to eventually overflow. Currently when this happens for the control that caused the overflow kctl->id.numid + kctl->count will also over flow causing it to be smaller than kctl->id.numid. Most of the code assumes that this is something that can not happen, so we need to make sure that it won't happen Signed-off-by: Lars-Peter Clausen Acked-by: Jaroslav Kysela Cc: Signed-off-by: Takashi Iwai (cherry picked from commit ac902c112d90a89e59916f751c2745f4dbdbb4bd) [wt: part 2 of CVE-2014-4656] Signed-off-by: Willy Tarreau --- sound/core/control.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sound/core/control.c b/sound/core/control.c index 80bb3ed7c548..d7f4644b8602 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -278,6 +278,10 @@ static unsigned int snd_ctl_hole_check(struct snd_card *card, { struct snd_kcontrol *kctl; + /* Make sure that the ids assigned to the control do not wrap around */ + if (card->last_numid >= UINT_MAX - count) + card->last_numid = 0; + list_for_each_entry(kctl, &card->controls, list) { if ((kctl->id.numid <= card->last_numid && kctl->id.numid + kctl->count > card->last_numid) || -- 2.47.3