USB: cxacru: check data length is not negative
When attempting to read data that is not actually
an array of values, the length may be negative
which causes an Oops due to a likely access off
the end of the data array.
This bug should not occur under normal use unless
the device returns an invalid response.
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/atm/cxacru.c b/drivers/usb/atm/cxacru.c
index 4a26a6c..8da4a06 100644
--- a/drivers/usb/atm/cxacru.c
+++ b/drivers/usb/atm/cxacru.c
@@ -596,7 +596,7 @@
len = ret / 4;
for (offb = 0; offb < len; ) {
int l = le32_to_cpu(buf[offb++]);
- if (l > stride || l > (len - offb) / 2) {
+ if (l < 0 || l > stride || l > (len - offb) / 2) {
if (printk_ratelimit())
usb_err(instance->usbatm, "invalid data length from cm %#x: %d\n",
cm, l);