6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> commit de28e469da75359a2bb8cd8778b78aa64b1be1f4 upstream. The usb_get_device_descriptor() routine reads the device descriptor from the udev device and stores it directly in udev->descriptor. This interface is error prone, because the USB subsystem expects in-memory copies of a device's descriptors to be immutable once the device has been initialized. The interface is changed so that the device descriptor is left in a kmalloc-ed buffer, not copied into the usb_device structure. A pointer to the buffer is returned to the caller, who is then responsible for kfree-ing it. The corresponding changes needed in the various callers are fairly small. Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/d0111bb6-56c1-4f90-adf2-6cfe152f6561@xxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/core/hcd.c | 10 +++++++--- drivers/usb/core/hub.c | 44 +++++++++++++++++++++++--------------------- drivers/usb/core/message.c | 29 ++++++++++++----------------- drivers/usb/core/usb.h | 4 ++-- 4 files changed, 44 insertions(+), 43 deletions(-) --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -983,6 +983,7 @@ static int register_root_hub(struct usb_ { struct device *parent_dev = hcd->self.controller; struct usb_device *usb_dev = hcd->self.root_hub; + struct usb_device_descriptor *descr; const int devnum = 1; int retval; @@ -994,13 +995,16 @@ static int register_root_hub(struct usb_ mutex_lock(&usb_bus_idr_lock); usb_dev->ep0.desc.wMaxPacketSize = cpu_to_le16(64); - retval = usb_get_device_descriptor(usb_dev, USB_DT_DEVICE_SIZE); - if (retval != sizeof usb_dev->descriptor) { + descr = usb_get_device_descriptor(usb_dev); + if (IS_ERR(descr)) { + retval = PTR_ERR(descr); mutex_unlock(&usb_bus_idr_lock); dev_dbg (parent_dev, "can't read %s device descriptor %d\n", dev_name(&usb_dev->dev), retval); - return (retval < 0) ? retval : -EMSGSIZE; + return retval; } + usb_dev->descriptor = *descr; + kfree(descr); if (le16_to_cpu(usb_dev->descriptor.bcdUSB) >= 0x0201) { retval = usb_get_bos_descriptor(usb_dev); --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2656,12 +2656,17 @@ int usb_authorize_device(struct usb_devi } if (usb_dev->wusb) { - result = usb_get_device_descriptor(usb_dev, sizeof(usb_dev->descriptor)); - if (result < 0) { + struct usb_device_descriptor *descr; + + descr = usb_get_device_descriptor(usb_dev); + if (IS_ERR(descr)) { + result = PTR_ERR(descr); dev_err(&usb_dev->dev, "can't re-read device descriptor for " "authorization: %d\n", result); goto error_device_descriptor; } + usb_dev->descriptor = *descr; + kfree(descr); } usb_dev->authorized = 1; @@ -4747,7 +4752,7 @@ hub_port_init(struct usb_hub *hub, struc const char *driver_name; bool do_new_scheme; int maxp0; - struct usb_device_descriptor *buf; + struct usb_device_descriptor *buf, *descr; buf = kmalloc(GET_DESCRIPTOR_BUFSIZE, GFP_NOIO); if (!buf) @@ -4984,15 +4989,16 @@ hub_port_init(struct usb_hub *hub, struc usb_ep0_reinit(udev); } - retval = usb_get_device_descriptor(udev, USB_DT_DEVICE_SIZE); - if (retval < (signed)sizeof(udev->descriptor)) { + descr = usb_get_device_descriptor(udev); + if (IS_ERR(descr)) { + retval = PTR_ERR(descr); if (retval != -ENODEV) dev_err(&udev->dev, "device descriptor read/all, error %d\n", retval); - if (retval >= 0) - retval = -ENOMSG; goto fail; } + udev->descriptor = *descr; + kfree(descr); /* * Some superspeed devices have finished the link training process @@ -5111,7 +5117,7 @@ hub_power_remaining(struct usb_hub *hub) static int descriptors_changed(struct usb_device *udev, - struct usb_device_descriptor *old_device_descriptor, + struct usb_device_descriptor *new_device_descriptor, struct usb_host_bos *old_bos) { int changed = 0; @@ -5122,8 +5128,8 @@ static int descriptors_changed(struct us int length; char *buf; - if (memcmp(&udev->descriptor, old_device_descriptor, - sizeof(*old_device_descriptor)) != 0) + if (memcmp(&udev->descriptor, new_device_descriptor, + sizeof(*new_device_descriptor)) != 0) return 1; if ((old_bos && !udev->bos) || (!old_bos && udev->bos)) @@ -5443,9 +5449,8 @@ static void hub_port_connect_change(stru { struct usb_port *port_dev = hub->ports[port1 - 1]; struct usb_device *udev = port_dev->child; - struct usb_device_descriptor descriptor; + struct usb_device_descriptor *descr; int status = -ENODEV; - int retval; dev_dbg(&port_dev->dev, "status %04x, change %04x, %s\n", portstatus, portchange, portspeed(hub, portstatus)); @@ -5472,23 +5477,20 @@ static void hub_port_connect_change(stru * changed device descriptors before resuscitating the * device. */ - descriptor = udev->descriptor; - retval = usb_get_device_descriptor(udev, - sizeof(udev->descriptor)); - if (retval < 0) { + descr = usb_get_device_descriptor(udev); + if (IS_ERR(descr)) { dev_dbg(&udev->dev, - "can't read device descriptor %d\n", - retval); + "can't read device descriptor %ld\n", + PTR_ERR(descr)); } else { - if (descriptors_changed(udev, &descriptor, + if (descriptors_changed(udev, descr, udev->bos)) { dev_dbg(&udev->dev, "device descriptor has changed\n"); - /* for disconnect() calls */ - udev->descriptor = descriptor; } else { status = 0; /* Nothing to do */ } + kfree(descr); } #ifdef CONFIG_PM } else if (udev->state == USB_STATE_SUSPENDED && --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -1039,40 +1039,35 @@ char *usb_cache_string(struct usb_device } /* - * usb_get_device_descriptor - (re)reads the device descriptor (usbcore) - * @dev: the device whose device descriptor is being updated - * @size: how much of the descriptor to read + * usb_get_device_descriptor - read the device descriptor + * @udev: the device whose device descriptor should be read * * Context: task context, might sleep. * - * Updates the copy of the device descriptor stored in the device structure, - * which dedicates space for this purpose. - * * Not exported, only for use by the core. If drivers really want to read * the device descriptor directly, they can call usb_get_descriptor() with * type = USB_DT_DEVICE and index = 0. * - * This call is synchronous, and may not be used in an interrupt context. - * - * Return: The number of bytes received on success, or else the status code - * returned by the underlying usb_control_msg() call. + * Returns: a pointer to a dynamically allocated usb_device_descriptor + * structure (which the caller must deallocate), or an ERR_PTR value. */ -int usb_get_device_descriptor(struct usb_device *dev, unsigned int size) +struct usb_device_descriptor *usb_get_device_descriptor(struct usb_device *udev) { struct usb_device_descriptor *desc; int ret; - if (size > sizeof(*desc)) - return -EINVAL; desc = kmalloc(sizeof(*desc), GFP_NOIO); if (!desc) - return -ENOMEM; + return ERR_PTR(-ENOMEM); + + ret = usb_get_descriptor(udev, USB_DT_DEVICE, 0, desc, sizeof(*desc)); + if (ret == sizeof(*desc)) + return desc; - ret = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, size); if (ret >= 0) - memcpy(&dev->descriptor, desc, size); + ret = -EMSGSIZE; kfree(desc); - return ret; + return ERR_PTR(ret); } /* --- a/drivers/usb/core/usb.h +++ b/drivers/usb/core/usb.h @@ -42,8 +42,8 @@ extern bool usb_endpoint_is_ignored(stru struct usb_endpoint_descriptor *epd); extern int usb_remove_device(struct usb_device *udev); -extern int usb_get_device_descriptor(struct usb_device *dev, - unsigned int size); +extern struct usb_device_descriptor *usb_get_device_descriptor( + struct usb_device *udev); extern int usb_set_isoch_delay(struct usb_device *dev); extern int usb_get_bos_descriptor(struct usb_device *dev); extern void usb_release_bos_descriptor(struct usb_device *dev);
