From 6aa35675bbc370e5f11baae7e01a9ab255d8030c Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 8 Mar 2006 15:14:09 -0500 Subject: [PATCH] [PATCH] USB: usbcore: Don't assume a USB configuration includes any interfaces In a couple of places, usbcore assumes that a USB device configuration will have a nonzero number of interfaces. Having no interfaces may or may not be allowed by the USB spec; in any event we shouldn't die if we encounter such a thing. This patch (as662) removes the assumptions. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 7dd28f8e1c..8e65f7a237 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -1179,8 +1179,11 @@ static int choose_configuration(struct usb_device *udev) c = udev->config; num_configs = udev->descriptor.bNumConfigurations; for (i = 0; i < num_configs; (i++, c++)) { - struct usb_interface_descriptor *desc = - &c->intf_cache[0]->altsetting->desc; + struct usb_interface_descriptor *desc = NULL; + + /* It's possible that a config has no interfaces! */ + if (c->desc.bNumInterfaces > 0) + desc = &c->intf_cache[0]->altsetting->desc; /* * HP's USB bus-powered keyboard has only one configuration @@ -1215,7 +1218,8 @@ static int choose_configuration(struct usb_device *udev) /* If the first config's first interface is COMM/2/0xff * (MSFT RNDIS), rule it out unless Linux has host-side * RNDIS support. */ - if (i == 0 && desc->bInterfaceClass == USB_CLASS_COMM + if (i == 0 && desc + && desc->bInterfaceClass == USB_CLASS_COMM && desc->bInterfaceSubClass == 2 && desc->bInterfaceProtocol == 0xff) { #ifndef CONFIG_USB_NET_RNDIS @@ -1231,8 +1235,8 @@ static int choose_configuration(struct usb_device *udev) * than a vendor-specific driver. */ else if (udev->descriptor.bDeviceClass != USB_CLASS_VENDOR_SPEC && - desc->bInterfaceClass != - USB_CLASS_VENDOR_SPEC) { + (!desc || desc->bInterfaceClass != + USB_CLASS_VENDOR_SPEC)) { best = c; break; } @@ -3024,7 +3028,7 @@ int usb_reset_device(struct usb_device *udev) parent_hub = hdev_to_hub(parent_hdev); /* If we're resetting an active hub, take some special actions */ - if (udev->actconfig && + if (udev->actconfig && udev->actconfig->desc.bNumInterfaces > 0 && udev->actconfig->interface[0]->dev.driver == &hub_driver.driver && (hub = hdev_to_hub(udev)) != NULL) { -- 2.39.5