usb/core/devio.c: Check for printer class specific request

In the usb printer class specific request get_device_id the value of
wIndex is (interface << 8 | altsetting) instead of just interface.
This enables the detection of some printers with libusb.

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthias Dellweg <2500@gmx.de>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 18 insertions, 3 deletions

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index eea53ebe6706..0ca54e22d319 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -609,9 +609,10 @@ static int findintfep(struct usb_device *dev, unsigned int ep)
 }
 
 static int check_ctrlrecip(struct dev_state *ps, unsigned int requesttype,
-                           unsigned int index)
+                           unsigned int request, unsigned int index)
 {
         int ret = 0;
+        struct usb_host_interface *alt_setting;
 
         if (ps->dev->state != USB_STATE_UNAUTHENTICATED
          && ps->dev->state != USB_STATE_ADDRESS
@@ -620,6 +621,19 @@ static int check_ctrlrecip(struct dev_state *ps, unsigned int requesttype,
         if (USB_TYPE_VENDOR == (USB_TYPE_MASK & requesttype))
                 return 0;
 
+        /*
+         * check for the special corner case 'get_device_id' in the printer
+         * class specification, where wIndex is (interface << 8 | altsetting)
+         * instead of just interface
+         */
+        if (requesttype == 0xa1 && request == 0) {
+                alt_setting = usb_find_alt_setting(ps->dev->actconfig,
+                                                   index >> 8, index & 0xff);
+                if (alt_setting
+                 && alt_setting->desc.bInterfaceClass == USB_CLASS_PRINTER)
+                        index >>= 8;
+        }
+
         index &= 0xff;
         switch (requesttype & USB_RECIP_MASK) {
         case USB_RECIP_ENDPOINT:
@@ -772,7 +786,8 @@ static int proc_control(struct dev_state *ps, void __user *arg)
 
         if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
                 return -EFAULT;
-        ret = check_ctrlrecip(ps, ctrl.bRequestType, ctrl.wIndex);
+        ret = check_ctrlrecip(ps, ctrl.bRequestType, ctrl.bRequest,
+                              ctrl.wIndex);
         if (ret)
                 return ret;
         wLength = ctrl.wLength;         /* To suppress 64k PAGE_SIZE warning */
@@ -1102,7 +1117,7 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb,
                         kfree(dr);
                         return -EINVAL;
                 }
-                ret = check_ctrlrecip(ps, dr->bRequestType,
+                ret = check_ctrlrecip(ps, dr->bRequestType, dr->bRequest,
                                       le16_to_cpup(&dr->wIndex));
                 if (ret) {
                         kfree(dr);