NET: cdc-phonet, handle empty phonet header

Currently, for N 5800 XM I get:
cdc_phonet: probe of 1-6:1.10 failed with error -22

It's because phonet_header is empty. Extra altsetting looks like
there:
E 05 24 00 01 10 03 24 ab 05 24 06 0a 0b 04 24 fd  .$....$..$....$.
E 00                                               .

I don't see the header used anywhere so just check if the phonet
descriptor is there, not the structure itself.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Cc: David S. Miller <davem@davemloft.net>
Acked-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 6 deletions

diff --git a/drivers/net/usb/cdc-phonet.c b/drivers/net/usb/cdc-phonet.c
index 4cf4e361c121..f967913e11bc 100644
--- a/drivers/net/usb/cdc-phonet.c
+++ b/drivers/net/usb/cdc-phonet.c
@@ -328,13 +328,13 @@ int usbpn_probe(struct usb_interface *intf, const struct usb_device_id *id)
 {
         static const char ifname[] = "usbpn%d";
         const struct usb_cdc_union_desc *union_header = NULL;
-        const struct usb_cdc_header_desc *phonet_header = NULL;
         const struct usb_host_interface *data_desc;
         struct usb_interface *data_intf;
         struct usb_device *usbdev = interface_to_usbdev(intf);
         struct net_device *dev;
         struct usbpn_dev *pnd;
         u8 *data;
+        int phonet = 0;
         int len, err;
 
         data = intf->altsetting->extra;
@@ -355,10 +355,7 @@ int usbpn_probe(struct usb_interface *intf, const struct usb_device_id *id)
                                         (struct usb_cdc_union_desc *)data;
                                 break;
                         case 0xAB:
-                                if (phonet_header || dlen < 5)
-                                        break;
-                                phonet_header =
-                                        (struct usb_cdc_header_desc *)data;
+                                phonet = 1;
                                 break;
                         }
                 }
@@ -366,7 +363,7 @@ int usbpn_probe(struct usb_interface *intf, const struct usb_device_id *id)
                 len -= dlen;
         }
 
-        if (!union_header || !phonet_header)
+        if (!union_header || !phonet)
                 return -EINVAL;
 
         data_intf = usb_ifnum_to_if(usbdev, union_header->bSlaveInterface0);