net: cdc_ether: fix divide by 0 on bad descriptors
Setting dev->hard_mtu to 0 will cause a divide error in
usbnet_probe. Protect against devices with bogus CDC Ethernet
functional descriptors by ignoring a zero wMaxSegmentSize.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index 3e7a3ac..05dca3e 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -230,7 +230,7 @@
goto bad_desc;
}
- if (header.usb_cdc_ether_desc) {
+ if (header.usb_cdc_ether_desc && info->ether->wMaxSegmentSize) {
dev->hard_mtu = le16_to_cpu(info->ether->wMaxSegmentSize);
/* because of Zaurus, we may be ignoring the host
* side link address we were given.
