Commit 447d6275 authored by Takashi Iwai's avatar Takashi Iwai

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

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
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 902eb7fd
......@@ -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 */
......
......@@ -438,6 +438,9 @@ static void snd_complete_urb(struct urb *urb)
*
* 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,
......
......@@ -1519,7 +1519,11 @@ 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(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(chip->dev,
......
......@@ -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;
......
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