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

commit 393cbb5151ecda9f9e14e3082d048dd27a1ff9f6 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 37518dfdeb987188089eb43c3147417ce14615a9..1d73709c41bdbfdc936d817a9539885f7ce8fe01 100644 (file)
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -607,9 +607,10 @@ 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
@@ -618,6 +619,19 @@ 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:
@@ -770,7 +784,8 @@ 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 */
@@ -1100,7 +1115,7 @@ 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);