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Commit 1a8e8fab authored by Valentine Barshak's avatar Valentine Barshak Committed by Jiri Kosina
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HID: Fix race between disconnect and hiddev_ioctl 



A USB HID device can be disconnected at any time.
If this happens right before or while hiddev_ioctl is in progress,
the hiddev_ioctl tries to access invalid hiddev->hid pointer.
When the hid device is disconnected, the hiddev_disconnect()
ends up with a call to hid_device_release() which frees
hid_device, but doesn't set the hiddev->hid pointer to NULL.
If the deallocated memory region has been re-used by the kernel,
this can cause a crash or memory corruption.

Since disconnect can happen at any time, we can't initialize
struct hid_device *hid = hiddev->hid at the beginning of ioctl
and then use it.

This change checks hiddev->exist flag while holding
the existancelock and uses hid_device only if it exists.

Signed-off-by: default avatarValentine Barshak <vbarshak@mvista.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent ce06b9d6

drivers/hid/usbhid/hiddev.c

+131 −37
Original line number Diff line number Diff line
@@ -586,7 +586,7 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
{

	struct hiddev_list *list = file->private_data;

	struct hiddev *hiddev = list->hiddev;

	struct hid_device *hid = hiddev->hid;

	struct hid_device *hid;

	struct usb_device *dev;

	struct hiddev_collection_info cinfo;

	struct hiddev_report_info rinfo;
@@ -594,26 +594,33 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
	struct hiddev_devinfo dinfo;

	struct hid_report *report;

	struct hid_field *field;

	struct usbhid_device *usbhid = hid->driver_data;

	struct usbhid_device *usbhid;

	void __user *user_arg = (void __user *)arg;

	int i, r;



	/* Called without BKL by compat methods so no BKL taken */



	/* FIXME: Who or what stop this racing with a disconnect ?? */

	if (!hiddev->exist || !hid)

	if (!hiddev->exist)

		return -EIO;



	dev = hid_to_usb_dev(hid);



	switch (cmd) {



	case HIDIOCGVERSION:

		return put_user(HID_VERSION, (int __user *)arg);



	case HIDIOCAPPLICATION:

		if (arg < 0 || arg >= hid->maxapplication)

			return -EINVAL;

		mutex_lock(&hiddev->existancelock);

		if (!hiddev->exist) {

			r = -ENODEV;

			goto ret_unlock;

		}



		hid = hiddev->hid;

		if (arg < 0 || arg >= hid->maxapplication) {

			r = -EINVAL;

			goto ret_unlock;

		}



		for (i = 0; i < hid->maxcollection; i++)

			if (hid->collection[i].type ==
@@ -621,11 +628,22 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
				break;



		if (i == hid->maxcollection)

			return -EINVAL;



		return hid->collection[i].usage;

			r = -EINVAL;

		else

			r = hid->collection[i].usage;

		goto ret_unlock;



	case HIDIOCGDEVINFO:

		mutex_lock(&hiddev->existancelock);

		if (!hiddev->exist) {

			r = -ENODEV;

			goto ret_unlock;

		}



		hid = hiddev->hid;

		dev = hid_to_usb_dev(hid);

		usbhid = hid->driver_data;



		dinfo.bustype = BUS_USB;

		dinfo.busnum = dev->bus->busnum;

		dinfo.devnum = dev->devnum;
@@ -634,6 +652,8 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		dinfo.product = le16_to_cpu(dev->descriptor.idProduct);

		dinfo.version = le16_to_cpu(dev->descriptor.bcdDevice);

		dinfo.num_applications = hid->maxapplication;

		mutex_unlock(&hiddev->existancelock);



		if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))

			return -EFAULT;
@@ -667,6 +687,7 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
			r = hiddev_ioctl_string(hiddev, cmd, user_arg);

		else

			r = -ENODEV;

ret_unlock:

		mutex_unlock(&hiddev->existancelock);

		return r;
@@ -676,6 +697,7 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
			mutex_unlock(&hiddev->existancelock);

			return -ENODEV;

		}

		hid = hiddev->hid;

		usbhid_init_reports(hid);

		mutex_unlock(&hiddev->existancelock);
@@ -688,14 +710,21 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		if (rinfo.report_type == HID_REPORT_TYPE_OUTPUT)

			return -EINVAL;



		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)

			return -EINVAL;



		mutex_lock(&hiddev->existancelock);

		if (hiddev->exist) {

		if (!hiddev->exist) {

			r = -ENODEV;

			goto ret_unlock;

		}



		hid = hiddev->hid;

		report = hiddev_lookup_report(hid, &rinfo);

		if (report == NULL) {

			r = -EINVAL;

			goto ret_unlock;

		}



		usbhid_submit_report(hid, report, USB_DIR_IN);

		usbhid_wait_io(hid);

		}

		mutex_unlock(&hiddev->existancelock);



		return 0;
@@ -707,14 +736,21 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		if (rinfo.report_type == HID_REPORT_TYPE_INPUT)

			return -EINVAL;



		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)

			return -EINVAL;



		mutex_lock(&hiddev->existancelock);

		if (hiddev->exist) {

		if (!hiddev->exist) {

			r = -ENODEV;

			goto ret_unlock;

		}



		hid = hiddev->hid;

		report = hiddev_lookup_report(hid, &rinfo);

		if (report == NULL) {

			r = -EINVAL;

			goto ret_unlock;

		}



		usbhid_submit_report(hid, report, USB_DIR_OUT);

		usbhid_wait_io(hid);

		}

		mutex_unlock(&hiddev->existancelock);



		return 0;
@@ -723,10 +759,21 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		if (copy_from_user(&rinfo, user_arg, sizeof(rinfo)))

			return -EFAULT;



		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)

			return -EINVAL;

		mutex_lock(&hiddev->existancelock);

		if (!hiddev->exist) {

			r = -ENODEV;

			goto ret_unlock;

		}



		hid = hiddev->hid;

		report = hiddev_lookup_report(hid, &rinfo);

		if (report == NULL) {

			r = -EINVAL;

			goto ret_unlock;

		}



		rinfo.num_fields = report->maxfield;

		mutex_unlock(&hiddev->existancelock);



		if (copy_to_user(user_arg, &rinfo, sizeof(rinfo)))

			return -EFAULT;
@@ -738,11 +785,23 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
			return -EFAULT;

		rinfo.report_type = finfo.report_type;

		rinfo.report_id = finfo.report_id;

		if ((report = hiddev_lookup_report(hid, &rinfo)) == NULL)

			return -EINVAL;

		mutex_lock(&hiddev->existancelock);

		if (!hiddev->exist) {

			r = -ENODEV;

			goto ret_unlock;

		}



		if (finfo.field_index >= report->maxfield)

			return -EINVAL;

		hid = hiddev->hid;

		report = hiddev_lookup_report(hid, &rinfo);

		if (report == NULL) {

			r = -EINVAL;

			goto ret_unlock;

		}



		if (finfo.field_index >= report->maxfield) {

			r = -EINVAL;

			goto ret_unlock;

		}



		field = report->field[finfo.field_index];

		memset(&finfo, 0, sizeof(finfo));
@@ -760,6 +819,7 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		finfo.physical_maximum = field->physical_maximum;

		finfo.unit_exponent = field->unit_exponent;

		finfo.unit = field->unit;

		mutex_unlock(&hiddev->existancelock);



		if (copy_to_user(user_arg, &finfo, sizeof(finfo)))

			return -EFAULT;
@@ -785,12 +845,22 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		if (copy_from_user(&cinfo, user_arg, sizeof(cinfo)))

			return -EFAULT;



		if (cinfo.index >= hid->maxcollection)

			return -EINVAL;

		mutex_lock(&hiddev->existancelock);

		if (!hiddev->exist) {

			r = -ENODEV;

			goto ret_unlock;

		}



		hid = hiddev->hid;

		if (cinfo.index >= hid->maxcollection) {

			r = -EINVAL;

			goto ret_unlock;

		}



		cinfo.type = hid->collection[cinfo.index].type;

		cinfo.usage = hid->collection[cinfo.index].usage;

		cinfo.level = hid->collection[cinfo.index].level;

		mutex_lock(&hiddev->existancelock);



		if (copy_to_user(user_arg, &cinfo, sizeof(cinfo)))

			return -EFAULT;
@@ -803,24 +873,48 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 


		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGNAME(0))) {

			int len;

			if (!hid->name)

				return 0;



			mutex_lock(&hiddev->existancelock);

			if (!hiddev->exist) {

				r = -ENODEV;

				goto ret_unlock;

			}



			hid = hiddev->hid;

			if (!hid->name) {

				r = 0;

				goto ret_unlock;

			}



			len = strlen(hid->name) + 1;

			if (len > _IOC_SIZE(cmd))

				 len = _IOC_SIZE(cmd);

			return copy_to_user(user_arg, hid->name, len) ?

			r = copy_to_user(user_arg, hid->name, len) ?

				-EFAULT : len;

			goto ret_unlock;

		}



		if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGPHYS(0))) {

			int len;

			if (!hid->phys)

				return 0;



			mutex_lock(&hiddev->existancelock);

			if (!hiddev->exist) {

				r = -ENODEV;

				goto ret_unlock;

			}



			hid = hiddev->hid;

			if (!hid->phys) {

				r = 0;

				goto ret_unlock;

			}



			len = strlen(hid->phys) + 1;

			if (len > _IOC_SIZE(cmd))

				len = _IOC_SIZE(cmd);

			return copy_to_user(user_arg, hid->phys, len) ?

			r = copy_to_user(user_arg, hid->phys, len) ?

				-EFAULT : len;

			goto ret_unlock;

		}

	}

	return -EINVAL;