On Tue, Oct 22, 2013 at 10:38:03AM +0100, Chris Wilson wrote:
> Prevent the user from passing in an ioctl command with up to 16,383
> bytes specified for the struct to be allocated and copied, and
> instead only allocate enough space to satisfy the kernel.
>
> Suggested-by: Pavel Roskin <proski@xxxxxxx>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Pavel Roskin <proski@xxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_drv.c | 30 +++++++++++++-----------------
> 1 file changed, 13 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 05ad9ba0a67e..8c5fbc9d41ad 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -354,6 +354,16 @@ static int drm_version(struct drm_device *dev, void *data,
> return err;
> }
>
> +static unsigned ioctl_size(unsigned kcmd, unsigned ucmd, unsigned *ksize, unsigned *usize)
> +{
> + *ksize = _IOC_SIZE(kcmd);
> + *usize = _IOC_SIZE(ucmd);
> + if (*usize > *ksize)
> + *usize = *ksize;
> +
> + return kcmd;
> +}
> +
> /**
> * Called whenever a process performs an ioctl on /dev/drm.
> *
> @@ -393,25 +403,11 @@ long drm_ioctl(struct file *filp,
> goto err_i1;
> if ((nr >= DRM_COMMAND_BASE) && (nr < DRM_COMMAND_END) &&
> (nr < DRM_COMMAND_BASE + dev->driver->num_ioctls)) {
> - u32 drv_size;
> ioctl = &dev->driver->ioctls[nr - DRM_COMMAND_BASE];
> - drv_size = _IOC_SIZE(ioctl->cmd_drv);
> - usize = asize = _IOC_SIZE(cmd);
> - if (drv_size > asize)
> - asize = drv_size;
> - cmd = ioctl->cmd_drv;
> - }
> - else if ((nr >= DRM_COMMAND_END) || (nr < DRM_COMMAND_BASE)) {
> - u32 drv_size;
> -
> + cmd = ioctl_size(ioctl->cmd_drv, cmd, &asize, &usize);
> + } else if ((nr >= DRM_COMMAND_END) || (nr < DRM_COMMAND_BASE)) {
> ioctl = &drm_ioctls[nr];
> -
> - drv_size = _IOC_SIZE(ioctl->cmd);
> - usize = asize = _IOC_SIZE(cmd);
> - if (drv_size > asize)
> - asize = drv_size;
> -
> - cmd = ioctl->cmd;
> + cmd = ioctl_size(ioctl->cmd, cmd, &asize, &usize);
> } else
> goto err_i1;
>
> --
> 1.8.4.rc3
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Ville Syrjälä
Intel OTC
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