rndis_wlan: resize bssid list if too small

Buffer used for bssid list might be too small. Change rndis_query_oid()
to return required buffer length to caller and make rndis_check_bssid_list()
resize buffer when needed.
Signed-off-by: NJussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rndis_wlan.c

@@ -676,7 +676,8 @@ static int rndis_query_oid(struct usbnet *dev, __le32 oid, void *data, int *len)
 
 	if (ret == 0) {
 		ret = le32_to_cpu(u.get_c->len);
-		*len = (*len > ret) ? ret : *len;
+		if (ret > *len)
+			*len = ret;
 		memcpy(data, u.buf + le32_to_cpu(u.get_c->offset) + 8, *len);
 		ret = rndis_error_status(u.get_c->status);
 
@@ -1656,6 +1657,9 @@ static struct cfg80211_bss *rndis_bss_info_update(struct usbnet *usbdev,
 	int ie_len, bssid_len;
 	u8 *ie;
 
+	devdbg(usbdev, " found bssid: '%.32s' [%pM]", bssid->ssid.essid,
+							bssid->mac);
+
 	/* parse bssid structure */
 	bssid_len = le32_to_cpu(bssid->length);
 
@@ -1695,10 +1699,12 @@ static int rndis_check_bssid_list(struct usbnet *usbdev)
 	struct ndis_80211_bssid_list_ex *bssid_list;
 	struct ndis_80211_bssid_ex *bssid;
 	int ret = -EINVAL, len, count, bssid_len;
+	bool resized = false;
 
 	devdbg(usbdev, "check_bssid_list");
 
 	len = CONTROL_BUFFER_SIZE;
+resize_buf:
 	buf = kmalloc(len, GFP_KERNEL);
 	if (!buf) {
 		ret = -ENOMEM;
@@ -1709,11 +1715,18 @@ static int rndis_check_bssid_list(struct usbnet *usbdev)
 	if (ret != 0)
 		goto out;
 
+	if (!resized && len > CONTROL_BUFFER_SIZE) {
+		resized = true;
+		kfree(buf);
+		goto resize_buf;
+	}
+
 	bssid_list = buf;
 	bssid = bssid_list->bssid;
 	bssid_len = le32_to_cpu(bssid->length);
 	count = le32_to_cpu(bssid_list->num_items);
-	devdbg(usbdev, "check_bssid_list: %d BSSIDs found", count);
+	devdbg(usbdev, "check_bssid_list: %d BSSIDs found (buflen: %d)", count,
+									len);
 
 	while (count && ((void *)bssid + bssid_len) <= (buf + len)) {
 		rndis_bss_info_update(usbdev, bssid);