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Commit c2667355 authored by Thomas Hellstrom's avatar Thomas Hellstrom
Browse files

drm: Break out ioctl permission check to a separate function v2 



Helps reviewing and understanding these checks.
v2: Remove misplaced newlines.

Signed-off-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
parent 09f308f7

drivers/gpu/drm/drm_drv.c

+75 −38
Original line number Diff line number Diff line
@@ -285,6 +285,44 @@ static int drm_version(struct drm_device *dev, void *data, 
	return err;

}



/**

 * drm_ioctl_permit - Check ioctl permissions against caller

 *

 * @flags: ioctl permission flags.

 * @file_priv: Pointer to struct drm_file identifying the caller.

 *

 * Checks whether the caller is allowed to run an ioctl with the

 * indicated permissions. If so, returns zero. Otherwise returns an

 * error code suitable for ioctl return.

 */

static int drm_ioctl_permit(u32 flags, struct drm_file *file_priv)

{

	/* ROOT_ONLY is only for CAP_SYS_ADMIN */

	if (unlikely((flags & DRM_ROOT_ONLY) && !capable(CAP_SYS_ADMIN)))

		return -EACCES;



	/* AUTH is only for authenticated or render client */

	if (unlikely((flags & DRM_AUTH) && !drm_is_render_client(file_priv) &&

		     !file_priv->authenticated))

		return -EACCES;



	/* MASTER is only for master */

	if (unlikely((flags & DRM_MASTER) && !file_priv->is_master))

		return -EACCES;



	/* Control clients must be explicitly allowed */

	if (unlikely(!(flags & DRM_CONTROL_ALLOW) &&

		     file_priv->minor->type == DRM_MINOR_CONTROL))

		return -EACCES;



	/* Render clients must be explicitly allowed */

	if (unlikely(!(flags & DRM_RENDER_ALLOW) &&

		     drm_is_render_client(file_priv)))

		return -EACCES;



	return 0;

}



/**

 * Called whenever a process performs an ioctl on /dev/drm.

 *
@@ -350,16 +388,16 @@ long drm_ioctl(struct file *filp, 
	/* Do not trust userspace, use our own definition */

	func = ioctl->func;



	if (!func) {

	if (unlikely(!func)) {

		DRM_DEBUG("no function\n");

		retcode = -EINVAL;

	} else if (((ioctl->flags & DRM_ROOT_ONLY) && !capable(CAP_SYS_ADMIN)) ||

		   ((ioctl->flags & DRM_AUTH) && !drm_is_render_client(file_priv) && !file_priv->authenticated) ||

		   ((ioctl->flags & DRM_MASTER) && !file_priv->is_master) ||

		   (!(ioctl->flags & DRM_CONTROL_ALLOW) && (file_priv->minor->type == DRM_MINOR_CONTROL)) ||

		   (!(ioctl->flags & DRM_RENDER_ALLOW) && drm_is_render_client(file_priv))) {

		retcode = -EACCES;

	} else {

		goto err_i1;

	}



	retcode = drm_ioctl_permit(ioctl->flags, file_priv);

	if (unlikely(retcode))

		goto err_i1;



	if (cmd & (IOC_IN | IOC_OUT)) {

		if (asize <= sizeof(stack_kdata)) {

			kdata = stack_kdata;
@@ -396,7 +434,6 @@ long drm_ioctl(struct file *filp, 
				 usize) != 0)

			retcode = -EFAULT;

	}

	}



      err_i1:

	if (!ioctl)