usbvision: fix overflow of interfaces array (CVE-2015-7833)

debian/changelog

@@ -1,3 +1,9 @@
+linux (4.2.5-2) UNRELEASED; urgency=medium
+
+  * usbvision: fix overflow of interfaces array (CVE-2015-7833)
+
+ -- Ben Hutchings <ben@decadent.org.uk>  Sun, 08 Nov 2015 14:47:40 +0000
+
 linux (4.2.5-1) unstable; urgency=medium
 
   * New upstream stable update:

debian/patches/bugfix/all/usbvision-fix-overflow-of-interfaces-array.patch

@@ -0,0 +1,31 @@
+From: Oliver Neukum <oneukum@suse.com>
+Date: Tue, 27 Oct 2015 12:42:38 +0100
+Subject: usbvision fix overflow of interfaces array
+Origin: https://bugzilla.novell.com/attachment.cgi?id=653350
+
+This fixes the crash reported in:
+http://seclists.org/bugtraq/2015/Oct/35
+The interface number needs a sanity check.
+
+Signed-off-by: Oliver Neukum <oneukum@suse.com>
+[bwh: Backported to 4.2: adjust context]
+---
+ drivers/media/usb/usbvision/usbvision-video.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+--- a/drivers/media/usb/usbvision/usbvision-video.c
++++ b/drivers/media/usb/usbvision/usbvision-video.c
+@@ -1533,6 +1533,13 @@ static int usbvision_probe(struct usb_in
+ 	printk(KERN_INFO "%s: %s found\n", __func__,
+ 				usbvision_device_data[model].model_string);
+ 
++	/*
++	 * this is a security check.
++	 * an exploit using an incorrect bInterfaceNumber is known
++	 */
++	if (ifnum >= USB_MAXINTERFACES || !dev->actconfig->interface[ifnum])
++		return -ENODEV;
++
+ 	if (usbvision_device_data[model].interface >= 0)
+ 		interface = &dev->actconfig->interface[usbvision_device_data[model].interface]->altsetting[0];
+ 	else

debian/patches/series

@@ -104,3 +104,4 @@ bugfix/all/KEYS-Don-t-permit-request_key-to-construct-a-new-key.patch
 
 debian/target-fix-abi-change-in-4.2.4.patch
 debian/signal-fix-abi-change-in-4.2.4.patch
+bugfix/all/usbvision-fix-overflow-of-interfaces-array.patch