rndis_host: fix oops when query for OID_GEN_PHYSICAL_MEDIUM fails

When query for OID_GEN_PHYSICAL_MEDIUM fails, uninitialized pointer
'phym' is being accessed in generic_rndis_bind(), resulting OOPS.
Patch fixes phym to be initialized and setup correctly when
rndis_query() for physical medium fails.

Bug was introduced by following commit:
commit 039ee17d1baabaa21783a0d5ab3e8c6d8c794bdf
Author: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Date:   Sun Jan 27 23:34:33 2008 +0200

Reported-by: Dmitri Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/net/usb/rndis_host.c b/drivers/net/usb/rndis_host.c
index 727547a2899..369c731114b 100644
--- a/drivers/net/usb/rndis_host.c
+++ b/drivers/net/usb/rndis_host.c
@@ -283,7 +283,7 @@ generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
                 struct rndis_set_c      *set_c;
                 struct rndis_halt       *halt;
         } u;
-        u32                     tmp, *phym;
+        u32                     tmp, phym_unspec, *phym;
         int                     reply_len;
         unsigned char           *bp;
 
@@ -363,12 +363,15 @@ generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
                 goto halt_fail_and_release;
 
         /* Check physical medium */
+        phym = NULL;
         reply_len = sizeof *phym;
         retval = rndis_query(dev, intf, u.buf, OID_GEN_PHYSICAL_MEDIUM,
                         0, (void **) &phym, &reply_len);
-        if (retval != 0)
+        if (retval != 0 || !phym) {
                 /* OID is optional so don't fail here. */
-                *phym = RNDIS_PHYSICAL_MEDIUM_UNSPECIFIED;
+                phym_unspec = RNDIS_PHYSICAL_MEDIUM_UNSPECIFIED;
+                phym = &phym_unspec;
+        }
         if ((flags & FLAG_RNDIS_PHYM_WIRELESS) &&
                         *phym != RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
                 if (netif_msg_probe(dev))