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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index 86f80c60b21f91202c8c17c40d7981c3d7f873f8..1329d7725196ae28462fe4d5efb2ddde4760f3d6 100644 (file)
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -283,6 +283,8 @@ 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 b0a0f2028319afccb6503fadbb987514de184b09..c42a4c0e95da3a05a428d9592541f38a58fe3a70 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 ca2d07378807372697b98e1a272d5d48a59a6222..ee4b3b901bf54cdaebd74ba248b12912c28ada0d 100644 (file)
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -1372,7 +1372,11 @@ 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 98ca3540514f82b65c08c1d81a5ddf69ca217c5d..1f498b1f88bd5b63844bf13b9869669114125a01 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;