Commit ea04efee authored by Dmitry Torokhov's avatar Dmitry Torokhov

Input: ims-psu - check if CDC union descriptor is sane

Before trying to use CDC union descriptor, try to validate whether that it
is sane by checking that intf->altsetting->extra is big enough and that
descriptor bLength is not too big and not too small.
Reported-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 20ac95d5
......@@ -1635,13 +1635,25 @@ ims_pcu_get_cdc_union_desc(struct usb_interface *intf)
return NULL;
}
while (buflen > 0) {
while (buflen >= sizeof(*union_desc)) {
union_desc = (struct usb_cdc_union_desc *)buf;
if (union_desc->bLength > buflen) {
dev_err(&intf->dev, "Too large descriptor\n");
return NULL;
}
if (union_desc->bDescriptorType == USB_DT_CS_INTERFACE &&
union_desc->bDescriptorSubType == USB_CDC_UNION_TYPE) {
dev_dbg(&intf->dev, "Found union header\n");
return union_desc;
if (union_desc->bLength >= sizeof(*union_desc))
return union_desc;
dev_err(&intf->dev,
"Union descriptor to short (%d vs %zd\n)",
union_desc->bLength, sizeof(*union_desc));
return NULL;
}
buflen -= union_desc->bLength;
......
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