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

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
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Cc: Moritz Muehlenhoff <jmm@inutil.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index 03fed6611d9e83d489e2ab66d94320c84eed4c18..56216a23277f3d064cb0c1f2a67133da469739ac 100644 (file)
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -285,6 +285,8 @@ static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
        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 */

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 114e3e7ff511d49897d292b541c634872614c656..e87436826b3b14ed511ee28fbbc5caf8c9513a41 100644 (file)
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -410,6 +410,9 @@ 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,

diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index 614f33e63c3a76d99a441ea202cf1652d1b98202..5bcf542b3a38a747a57d857fce23249e75d1bd0b 100644 (file)
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -1456,7 +1456,11 @@ static int snd_microii_spdif_default_get(struct snd_kcontrol *kcontrol,
 
        /* 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,

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index c62a1659106d2c3da63152d59e1302e2eee47d6d..0bf61d4a10802285a96982dbe74f4b747a6fd2af 100644 (file)
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -159,6 +159,8 @@ static int init_pitch_v1(struct snd_usb_audio *chip, int iface,
        unsigned char data[1];
        int err;
 
+       if (get_iface_desc(alts)->bNumEndpoints < 1)
+               return -EINVAL;
        ep = get_endpoint(alts, 0)->bEndpointAddress;
 
        data[0] = 1;