ALSA: usb-audio: fix sync-ep altsetting sanity check
diff mbox series

Message ID 20200114083953.1106-1-johan@kernel.org
State New
Headers show
Series
  • ALSA: usb-audio: fix sync-ep altsetting sanity check
Related show

Commit Message

Johan Hovold Jan. 14, 2020, 8:39 a.m. UTC
The altsetting sanity check in set_sync_ep_implicit_fb_quirk() was
checking for there to be at least one altsetting but then went on to
access the second one, which may not exist.

This could lead to random slab data being used to initialise the sync
endpoint in snd_usb_add_endpoint().

Fixes: c75a8a7ae565 ("ALSA: snd-usb: add support for implicit feedback")
Fixes: ca10a7ebdff1 ("ALSA: usb-audio: FT C400 sync playback EP to capture EP")
Fixes: 5e35dc0338d8 ("ALSA: usb-audio: add implicit fb quirk for Behringer UFX1204")
Fixes: 17f08b0d9aaf ("ALSA: usb-audio: add implicit fb quirk for Axe-Fx II")
Fixes: 103e9625647a ("ALSA: usb-audio: simplify set_sync_ep_implicit_fb_quirk")
Cc: stable <stable@vger.kernel.org>     # 3.5
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 sound/usb/pcm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Takashi Iwai Jan. 14, 2020, 8:42 a.m. UTC | #1
On Tue, 14 Jan 2020 09:39:53 +0100,
Johan Hovold wrote:
> 
> The altsetting sanity check in set_sync_ep_implicit_fb_quirk() was
> checking for there to be at least one altsetting but then went on to
> access the second one, which may not exist.
> 
> This could lead to random slab data being used to initialise the sync
> endpoint in snd_usb_add_endpoint().
> 
> Fixes: c75a8a7ae565 ("ALSA: snd-usb: add support for implicit feedback")
> Fixes: ca10a7ebdff1 ("ALSA: usb-audio: FT C400 sync playback EP to capture EP")
> Fixes: 5e35dc0338d8 ("ALSA: usb-audio: add implicit fb quirk for Behringer UFX1204")
> Fixes: 17f08b0d9aaf ("ALSA: usb-audio: add implicit fb quirk for Axe-Fx II")
> Fixes: 103e9625647a ("ALSA: usb-audio: simplify set_sync_ep_implicit_fb_quirk")
> Cc: stable <stable@vger.kernel.org>     # 3.5
> Signed-off-by: Johan Hovold <johan@kernel.org>

Thanks, applied now.


Takashi

Patch
diff mbox series

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index a11c8150af58..0e4eab96e23e 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -370,7 +370,7 @@  static int set_sync_ep_implicit_fb_quirk(struct snd_usb_substream *subs,
 add_sync_ep_from_ifnum:
 	iface = usb_ifnum_to_if(dev, ifnum);
 
-	if (!iface || iface->num_altsetting == 0)
+	if (!iface || iface->num_altsetting < 2)
 		return -EINVAL;
 
 	alts = &iface->altsetting[1];