[ 28/54] cdc_ether: Ignore bogus union descriptor for RNDIS devices

From: Greg KH
Date: Fri May 18 2012 - 19:28:40 EST


3.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Bjørn Mork <bjorn@xxxxxxx>

commit 6eddcb4c82883451aec3be1240f17793370fa62f upstream.

Some RNDIS devices include a bogus CDC Union descriptor pointing
to non-existing interfaces. The RNDIS code is already prepared
to handle devices without a CDC Union descriptor by hardwiring
the driver to use interfaces 0 and 1, which is correct for the
devices with the bogus descriptor as well. So we can reuse the
existing workaround.

Cc: Markus Kolb <linux-201011@xxxxxxxxxxxx>
Cc: Iker Salmón San Millán <shaola@xxxxxxxxxxxx>
Cc: Jonathan Nieder <jrnieder@xxxxxxxxx>
Cc: Oliver Neukum <oliver@xxxxxxxxxx>
Cc: 655387@xxxxxxxxxxxxxxx
Signed-off-by: Bjørn Mork <bjorn@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/net/usb/cdc_ether.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -83,6 +83,7 @@ int usbnet_generic_cdc_bind(struct usbne
struct cdc_state *info = (void *) &dev->data;
int status;
int rndis;
+ bool android_rndis_quirk = false;
struct usb_driver *driver = driver_of(intf);
struct usb_cdc_mdlm_desc *desc = NULL;
struct usb_cdc_mdlm_detail_desc *detail = NULL;
@@ -195,6 +196,11 @@ int usbnet_generic_cdc_bind(struct usbne
info->control,
info->u->bSlaveInterface0,
info->data);
+ /* fall back to hard-wiring for RNDIS */
+ if (rndis) {
+ android_rndis_quirk = true;
+ goto next_desc;
+ }
goto bad_desc;
}
if (info->control != intf) {
@@ -271,11 +277,15 @@ next_desc:
/* Microsoft ActiveSync based and some regular RNDIS devices lack the
* CDC descriptors, so we'll hard-wire the interfaces and not check
* for descriptors.
+ *
+ * Some Android RNDIS devices have a CDC Union descriptor pointing
+ * to non-existing interfaces. Ignore that and attempt the same
+ * hard-wired 0 and 1 interfaces.
*/
- if (rndis && !info->u) {
+ if (rndis && (!info->u || android_rndis_quirk)) {
info->control = usb_ifnum_to_if(dev->udev, 0);
info->data = usb_ifnum_to_if(dev->udev, 1);
- if (!info->control || !info->data) {
+ if (!info->control || !info->data || info->control != intf) {
dev_dbg(&intf->dev,
"rndis: master #0/%p slave #1/%p\n",
info->control,


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