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SubjectRe: [PATCH] uinput strnlen bugfix
On Mon, Feb 07, 2011 at 11:38:48PM -0800, Dmitry Torokhov wrote:
> Input: uinput - use memdup_user() and friends
>
> From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>
> Instead of open-coding copying of data structures from userspace use
> memdup_user() and strndup_user(). Note that this introduces change in
> behavior because driver used to truncate 'phys' longer than 1024 bytes,
> but now it will refuse to set 'phys' that long. Arguably trying to set
> such 'phys' is suspect anyways.
>
> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
> ---
>
> drivers/input/misc/uinput.c | 35 ++++++++++-------------------------
> 1 files changed, 10 insertions(+), 25 deletions(-)
>
>
> diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
> index c0888e3..7f8331f 100644
> --- a/drivers/input/misc/uinput.c
> +++ b/drivers/input/misc/uinput.c
> @@ -361,14 +361,9 @@ static int uinput_setup_device(struct uinput_device *udev, const char __user *bu
>
> dev = udev->dev;
>
> - user_dev = kmalloc(sizeof(struct uinput_user_dev), GFP_KERNEL);
> - if (!user_dev)
> - return -ENOMEM;
> -
> - if (copy_from_user(user_dev, buffer, sizeof(struct uinput_user_dev))) {
> - retval = -EFAULT;
> - goto exit;
> - }
> + user_dev = memdup_user(buffer, sizeof(struct uinput_user_dev));
> + if (!IS_ERR(user_dev))
> + return PTR_ERR(user_dev);
>
> udev->ff_effects_max = user_dev->ff_effects_max;
>
> @@ -621,7 +616,6 @@ static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
> struct uinput_ff_upload ff_up;
> struct uinput_ff_erase ff_erase;
> struct uinput_request *req;
> - int length;
> char *phys;
>
> retval = mutex_lock_interruptible(&udev->mutex);
> @@ -688,24 +682,15 @@ static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
> retval = -EINVAL;
> goto out;
> }
> - length = strnlen_user(p, 1024);
> - if (length <= 0) {
> - retval = -EFAULT;
> - break;
> +
> + phys = strndup_user(p, 1024);
> + if (IS_ERR(phys)) {
> + retval = PTR_ERR(phys);
> + goto out;
> }
> +
> kfree(udev->dev->phys);
> - udev->dev->phys = phys = kmalloc(length, GFP_KERNEL);
> - if (!phys) {
> - retval = -ENOMEM;
> - break;
> - }
> - if (copy_from_user(phys, p, length)) {
> - udev->dev->phys = NULL;
> - kfree(phys);
> - retval = -EFAULT;
> - break;
> - }
> - phys[length - 1] = '\0';
> + udev->dev->phys = phys;
> break;
>
> case UI_BEGIN_FF_UPLOAD:
looks good to me
Acked-by: Aristeu Rozanski <aris@ruivo.org>

--
Aristeu



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