cdc-acm: prevent infinite loop when parsing CDC headers.

[pandora-kernel.git] / drivers / usb / class / cdc-acm.c

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 360ddb5..57d6302 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -947,11 +947,16 @@ static int acm_probe(struct usb_interface *intf,
        }
 
        while (buflen > 0) {
+               elength = buffer[0];
+               if (!elength) {
+                       dev_err(&intf->dev, "skipping garbage byte\n");
+                       elength = 1;
+                       goto next_desc;
+               }
                if (buffer[1] != USB_DT_CS_INTERFACE) {
                        dev_err(&intf->dev, "skipping garbage\n");
                        goto next_desc;
                }
-               elength = buffer[0];
 
                switch (buffer[2]) {
                case USB_CDC_UNION_TYPE: /* we've found it */