drm: Break out ioctl permission check to a separate function v2
Helps reviewing and understanding these checks. v2: Remove misplaced newlines. Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
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09f308f7b6
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c266735561
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@ -285,6 +285,44 @@ static int drm_version(struct drm_device *dev, void *data,
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return err;
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}
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/**
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* drm_ioctl_permit - Check ioctl permissions against caller
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*
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* @flags: ioctl permission flags.
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* @file_priv: Pointer to struct drm_file identifying the caller.
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*
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* Checks whether the caller is allowed to run an ioctl with the
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* indicated permissions. If so, returns zero. Otherwise returns an
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* error code suitable for ioctl return.
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*/
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static int drm_ioctl_permit(u32 flags, struct drm_file *file_priv)
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{
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/* ROOT_ONLY is only for CAP_SYS_ADMIN */
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if (unlikely((flags & DRM_ROOT_ONLY) && !capable(CAP_SYS_ADMIN)))
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return -EACCES;
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/* AUTH is only for authenticated or render client */
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if (unlikely((flags & DRM_AUTH) && !drm_is_render_client(file_priv) &&
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!file_priv->authenticated))
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return -EACCES;
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/* MASTER is only for master */
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if (unlikely((flags & DRM_MASTER) && !file_priv->is_master))
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return -EACCES;
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/* Control clients must be explicitly allowed */
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if (unlikely(!(flags & DRM_CONTROL_ALLOW) &&
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file_priv->minor->type == DRM_MINOR_CONTROL))
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return -EACCES;
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/* Render clients must be explicitly allowed */
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if (unlikely(!(flags & DRM_RENDER_ALLOW) &&
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drm_is_render_client(file_priv)))
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return -EACCES;
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return 0;
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}
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/**
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* Called whenever a process performs an ioctl on /dev/drm.
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*
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@ -350,52 +388,51 @@ long drm_ioctl(struct file *filp,
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/* Do not trust userspace, use our own definition */
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func = ioctl->func;
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if (!func) {
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if (unlikely(!func)) {
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DRM_DEBUG("no function\n");
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retcode = -EINVAL;
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} else if (((ioctl->flags & DRM_ROOT_ONLY) && !capable(CAP_SYS_ADMIN)) ||
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((ioctl->flags & DRM_AUTH) && !drm_is_render_client(file_priv) && !file_priv->authenticated) ||
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((ioctl->flags & DRM_MASTER) && !file_priv->is_master) ||
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(!(ioctl->flags & DRM_CONTROL_ALLOW) && (file_priv->minor->type == DRM_MINOR_CONTROL)) ||
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(!(ioctl->flags & DRM_RENDER_ALLOW) && drm_is_render_client(file_priv))) {
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retcode = -EACCES;
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} else {
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if (cmd & (IOC_IN | IOC_OUT)) {
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if (asize <= sizeof(stack_kdata)) {
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kdata = stack_kdata;
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} else {
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kdata = kmalloc(asize, GFP_KERNEL);
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if (!kdata) {
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retcode = -ENOMEM;
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goto err_i1;
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}
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}
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if (asize > usize)
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memset(kdata + usize, 0, asize - usize);
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}
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goto err_i1;
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}
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if (cmd & IOC_IN) {
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if (copy_from_user(kdata, (void __user *)arg,
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usize) != 0) {
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retcode = -EFAULT;
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retcode = drm_ioctl_permit(ioctl->flags, file_priv);
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if (unlikely(retcode))
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goto err_i1;
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if (cmd & (IOC_IN | IOC_OUT)) {
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if (asize <= sizeof(stack_kdata)) {
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kdata = stack_kdata;
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} else {
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kdata = kmalloc(asize, GFP_KERNEL);
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if (!kdata) {
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retcode = -ENOMEM;
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goto err_i1;
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}
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} else
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memset(kdata, 0, usize);
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if (ioctl->flags & DRM_UNLOCKED)
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retcode = func(dev, kdata, file_priv);
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else {
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mutex_lock(&drm_global_mutex);
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retcode = func(dev, kdata, file_priv);
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mutex_unlock(&drm_global_mutex);
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}
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if (asize > usize)
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memset(kdata + usize, 0, asize - usize);
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}
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if (cmd & IOC_OUT) {
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if (copy_to_user((void __user *)arg, kdata,
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usize) != 0)
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retcode = -EFAULT;
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if (cmd & IOC_IN) {
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if (copy_from_user(kdata, (void __user *)arg,
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usize) != 0) {
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retcode = -EFAULT;
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goto err_i1;
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}
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} else
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memset(kdata, 0, usize);
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if (ioctl->flags & DRM_UNLOCKED)
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retcode = func(dev, kdata, file_priv);
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else {
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mutex_lock(&drm_global_mutex);
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retcode = func(dev, kdata, file_priv);
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mutex_unlock(&drm_global_mutex);
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}
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if (cmd & IOC_OUT) {
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if (copy_to_user((void __user *)arg, kdata,
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usize) != 0)
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retcode = -EFAULT;
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}
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err_i1:
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