From: Oliver Neukum Date: Tue, 16 Dec 2008 09:55:15 +0000 (+0100) Subject: HID: hiddev cleanup -- handle all error conditions properly X-Git-Tag: v2.6.29-rc1~498^2~5 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=079034073fa;p=linux-2.6-omap-h63xx.git HID: hiddev cleanup -- handle all error conditions properly This is a cleanup of hiddev and fixes the following issues: - thread safety by locking in read & ioctl, introducing a per device mutex - race between ioctl and disconnect, introducing a flag and locking in form of a per low level device mutex - race between open and other methods, making sure only successfully opened devices are put on the list, changing order of events - range checking both upper and lower limits of the minor range - make sure further calls to open fail for unplugged devices even if the device still has opened files - error checking for low level open - possible loss of wakeup events, using standard waiting macros - race in initialisation by moving registration after full initialisation Signed-off-by: Oliver Neukum Signed-off-by: Jiri Kosina --- diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c index 83e851a5ed3..6a98f9f572b 100644 --- a/drivers/hid/usbhid/hiddev.c +++ b/drivers/hid/usbhid/hiddev.c @@ -49,6 +49,7 @@ struct hiddev { int exist; int open; + struct mutex existancelock; wait_queue_head_t wait; struct hid_device *hid; struct list_head list; @@ -63,6 +64,7 @@ struct hiddev_list { struct fasync_struct *fasync; struct hiddev *hiddev; struct list_head node; + struct mutex thread_lock; }; static struct hiddev *hiddev_table[HIDDEV_MINORS]; @@ -264,29 +266,48 @@ static int hiddev_release(struct inode * inode, struct file * file) static int hiddev_open(struct inode *inode, struct file *file) { struct hiddev_list *list; - unsigned long flags; + int res; int i = iminor(inode) - HIDDEV_MINOR_BASE; - if (i >= HIDDEV_MINORS || !hiddev_table[i]) + if (i >= HIDDEV_MINORS || i < 0 || !hiddev_table[i]) return -ENODEV; if (!(list = kzalloc(sizeof(struct hiddev_list), GFP_KERNEL))) return -ENOMEM; + mutex_init(&list->thread_lock); list->hiddev = hiddev_table[i]; - spin_lock_irqsave(&list->hiddev->list_lock, flags); - list_add_tail(&list->node, &hiddev_table[i]->list); - spin_unlock_irqrestore(&list->hiddev->list_lock, flags); file->private_data = list; - if (!list->hiddev->open++) - if (list->hiddev->exist) - usbhid_open(hiddev_table[i]->hid); + /* + * no need for locking because the USB major number + * is shared which usbcore guards against disconnect + */ + if (list->hiddev->exist) { + if (!list->hiddev->open++) { + res = usbhid_open(hiddev_table[i]->hid); + if (res < 0) { + res = -EIO; + goto bail; + } + } + } else { + res = -ENODEV; + goto bail; + } + + spin_lock_irq(&list->hiddev->list_lock); + list_add_tail(&list->node, &hiddev_table[i]->list); + spin_unlock_irq(&list->hiddev->list_lock); return 0; +bail: + file->private_data = NULL; + kfree(list->hiddev); + return res; } /* @@ -305,7 +326,7 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun DECLARE_WAITQUEUE(wait, current); struct hiddev_list *list = file->private_data; int event_size; - int retval = 0; + int retval; event_size = ((list->flags & HIDDEV_FLAG_UREF) != 0) ? sizeof(struct hiddev_usage_ref) : sizeof(struct hiddev_event); @@ -313,10 +334,14 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun if (count < event_size) return 0; + /* lock against other threads */ + retval = mutex_lock_interruptible(&list->thread_lock); + if (retval) + return -ERESTARTSYS; + while (retval == 0) { if (list->head == list->tail) { - add_wait_queue(&list->hiddev->wait, &wait); - set_current_state(TASK_INTERRUPTIBLE); + prepare_to_wait(&list->hiddev->wait, &wait, TASK_INTERRUPTIBLE); while (list->head == list->tail) { if (file->f_flags & O_NONBLOCK) { @@ -332,35 +357,45 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun break; } + /* let O_NONBLOCK tasks run */ + mutex_unlock(&list->thread_lock); schedule(); + if (mutex_lock_interruptible(&list->thread_lock)) + return -EINTR; set_current_state(TASK_INTERRUPTIBLE); } + finish_wait(&list->hiddev->wait, &wait); - set_current_state(TASK_RUNNING); - remove_wait_queue(&list->hiddev->wait, &wait); } - if (retval) + if (retval) { + mutex_unlock(&list->thread_lock); return retval; + } while (list->head != list->tail && retval + event_size <= count) { if ((list->flags & HIDDEV_FLAG_UREF) == 0) { - if (list->buffer[list->tail].field_index != - HID_FIELD_INDEX_NONE) { + if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE) { struct hiddev_event event; + event.hid = list->buffer[list->tail].usage_code; event.value = list->buffer[list->tail].value; - if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event))) + if (copy_to_user(buffer + retval, &event, sizeof(struct hiddev_event))) { + mutex_unlock(&list->thread_lock); return -EFAULT; + } retval += sizeof(struct hiddev_event); } } else { if (list->buffer[list->tail].field_index != HID_FIELD_INDEX_NONE || (list->flags & HIDDEV_FLAG_REPORT) != 0) { - if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref))) + + if (copy_to_user(buffer + retval, list->buffer + list->tail, sizeof(struct hiddev_usage_ref))) { + mutex_unlock(&list->thread_lock); return -EFAULT; + } retval += sizeof(struct hiddev_usage_ref); } } @@ -368,6 +403,7 @@ static ssize_t hiddev_read(struct file * file, char __user * buffer, size_t coun } } + mutex_unlock(&list->thread_lock); return retval; } @@ -555,7 +591,7 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) struct hid_field *field; struct usbhid_device *usbhid = hid->driver_data; void __user *user_arg = (void __user *)arg; - int i; + int i, r; /* Called without BKL by compat methods so no BKL taken */ @@ -619,10 +655,22 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) } case HIDIOCGSTRING: - return hiddev_ioctl_string(hiddev, cmd, user_arg); + mutex_lock(&hiddev->existancelock); + if (!hiddev->exist) + r = hiddev_ioctl_string(hiddev, cmd, user_arg); + else + r = -ENODEV; + mutex_unlock(&hiddev->existancelock); + return r; case HIDIOCINITREPORT: + mutex_lock(&hiddev->existancelock); + if (!hiddev->exist) { + mutex_unlock(&hiddev->existancelock); + return -ENODEV; + } usbhid_init_reports(hid); + mutex_unlock(&hiddev->existancelock); return 0; @@ -636,8 +684,12 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL) return -EINVAL; - usbhid_submit_report(hid, report, USB_DIR_IN); - usbhid_wait_io(hid); + mutex_lock(&hiddev->existancelock); + if (hiddev->exist) { + usbhid_submit_report(hid, report, USB_DIR_IN); + usbhid_wait_io(hid); + } + mutex_unlock(&hiddev->existancelock); return 0; @@ -651,8 +703,12 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL) return -EINVAL; - usbhid_submit_report(hid, report, USB_DIR_OUT); - usbhid_wait_io(hid); + mutex_lock(&hiddev->existancelock); + if (hiddev->exist) { + usbhid_submit_report(hid, report, USB_DIR_OUT); + usbhid_wait_io(hid); + } + mutex_unlock(&hiddev->existancelock); return 0; @@ -710,7 +766,13 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case HIDIOCGUSAGES: case HIDIOCSUSAGES: case HIDIOCGCOLLECTIONINDEX: - return hiddev_ioctl_usage(hiddev, cmd, user_arg); + mutex_lock(&hiddev->existancelock); + if (hiddev->exist) + r = hiddev_ioctl_usage(hiddev, cmd, user_arg); + else + r = -ENODEV; + mutex_unlock(&hiddev->existancelock); + return r; case HIDIOCGCOLLECTIONINFO: if (copy_from_user(&cinfo, user_arg, sizeof(cinfo))) @@ -808,23 +870,22 @@ int hiddev_connect(struct hid_device *hid, unsigned int force) if (!(hiddev = kzalloc(sizeof(struct hiddev), GFP_KERNEL))) return -1; - retval = usb_register_dev(usbhid->intf, &hiddev_class); - if (retval) { - err_hid("Not able to get a minor for this device."); - kfree(hiddev); - return -1; - } - init_waitqueue_head(&hiddev->wait); INIT_LIST_HEAD(&hiddev->list); spin_lock_init(&hiddev->list_lock); + mutex_init(&hiddev->existancelock); hiddev->hid = hid; hiddev->exist = 1; - hid->minor = usbhid->intf->minor; - hid->hiddev = hiddev; - - hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev; + retval = usb_register_dev(usbhid->intf, &hiddev_class); + if (retval) { + err_hid("Not able to get a minor for this device."); + kfree(hiddev); + return -1; + } else { + hid->minor = usbhid->intf->minor; + hiddev_table[usbhid->intf->minor - HIDDEV_MINOR_BASE] = hiddev; + } return 0; } @@ -839,7 +900,9 @@ void hiddev_disconnect(struct hid_device *hid) struct hiddev *hiddev = hid->hiddev; struct usbhid_device *usbhid = hid->driver_data; + mutex_lock(&hiddev->existancelock); hiddev->exist = 0; + mutex_unlock(&hiddev->existancelock); hiddev_table[hiddev->hid->minor - HIDDEV_MINOR_BASE] = NULL; usb_deregister_dev(usbhid->intf, &hiddev_class);