Patch "ALSA: usb-audio: Add sanity checks for endpoint accesses" has been added to the 3.14-stable tree

This is a note to let you know that I've just added the patch titled

ALSA: usb-audio: Add sanity checks for endpoint accesses

to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
alsa-usb-audio-add-sanity-checks-for-endpoint-accesses.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Takashi Iwai <[email protected]>
Date: Tue, 15 Mar 2016 15:20:58 +0100
Subject: ALSA: usb-audio: Add sanity checks for endpoint accesses

From: Takashi Iwai <[email protected]>

commit 447d6275f0c21f6cc97a88b3a0c601436a4cdf2a upstream.

Add some sanity check codes before actually accessing the endpoint via get_endpoint() in order to avoid the invalid access through a malformed USB descriptor. Mostly just checking bNumEndpoints, but in one place (snd_microii_spdif_default_get()), the validity of iface and altsetting index is checked as well.

Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=971125

---
 sound/usb/clock.c        |    2 ++
 sound/usb/endpoint.c     |    3 +++
 sound/usb/mixer_quirks.c |    4 ++++
 sound/usb/pcm.c          |    2 ++
 4 files changed, 11 insertions(+)

@@ -283,6 +283,8 @@ static int set_sample_rate_v1(struct snd
 	unsigned char data[3];
 	int err, crate;
 
+	if (get_iface_desc(alts)->bNumEndpoints < 1)
+		return -EINVAL;
 	ep = get_endpoint(alts, 0)->bEndpointAddress;
 
 	/* if endpoint doesn't have sampling rate control, bail out */

@@ -409,6 +409,9 @@ exit_clear:
  *
  * New endpoints will be added to chip->ep_list and must be freed by
  * calling snd_usb_endpoint_free().
+ *
+ * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
+ * bNumEndpoints > 1 beforehand.
  */
 struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
 					      struct usb_host_interface *alts,

@@ -1455,7 +1455,11 @@ static int snd_microii_spdif_default_get
 
 	/* use known values for that card: interface#1 altsetting#1 */
 	iface = usb_ifnum_to_if(mixer->chip->dev, 1);
+	if (!iface || iface->num_altsetting < 2)
+		return -EINVAL;
 	alts = &iface->altsetting[1];
+	if (get_iface_desc(alts)->bNumEndpoints < 1)
+		return -EINVAL;
 	ep = get_endpoint(alts, 0)->bEndpointAddress;
 
 	err = snd_usb_ctl_msg(mixer->chip->dev,

@@ -159,6 +159,8 @@ static int init_pitch_v1(struct snd_usb_
 	unsigned char data[1];
 	int err;
 
+	if (get_iface_desc(alts)->bNumEndpoints < 1)
+		return -EINVAL;
 	ep = get_endpoint(alts, 0)->bEndpointAddress;
 
 	data[0] = 1;

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/alsa-usb-audio-fix-null-dereference-in-create_fixed_stream_quirk.patch queue-3.14/alsa-usb-audio-minor-code-cleanup-in-create_fixed_stream_quirk.patch queue-3.14/alsa-usb-audio-fix-double-free-in-error-paths-after-snd_usb_add_audio_stream-call.patch queue-3.14/alsa-usb-audio-add-sanity-checks-for-endpoint-accesses.patch