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

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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>
This commit is contained in:
Thomas Hellstrom 2014-03-13 10:30:25 +01:00
parent 09f308f7b6
commit c266735561
1 changed files with 75 additions and 38 deletions
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113
drivers/gpu/drm/drm_drv.c
View file

@ -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.
*
@ -350,52 +388,51 @@ 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 {
if (cmd & (IOC_IN | IOC_OUT)) {
if (asize <= sizeof(stack_kdata)) {
kdata = stack_kdata;
} else {
kdata = kmalloc(asize, GFP_KERNEL);
if (!kdata) {
retcode = -ENOMEM;
goto err_i1;
}
}
if (asize > usize)
memset(kdata + usize, 0, asize - usize);
}
goto err_i1;
}
if (cmd & IOC_IN) {
if (copy_from_user(kdata, (void __user *)arg,
usize) != 0) {
retcode = -EFAULT;
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;
} else {
kdata = kmalloc(asize, GFP_KERNEL);
if (!kdata) {
retcode = -ENOMEM;
goto err_i1;
}
} else
memset(kdata, 0, usize);
if (ioctl->flags & DRM_UNLOCKED)
retcode = func(dev, kdata, file_priv);
else {
mutex_lock(&drm_global_mutex);
retcode = func(dev, kdata, file_priv);
mutex_unlock(&drm_global_mutex);
}
if (asize > usize)
memset(kdata + usize, 0, asize - usize);
}
if (cmd & IOC_OUT) {
if (copy_to_user((void __user *)arg, kdata,
usize) != 0)
retcode = -EFAULT;
if (cmd & IOC_IN) {
if (copy_from_user(kdata, (void __user *)arg,
usize) != 0) {
retcode = -EFAULT;
goto err_i1;
}
} else
memset(kdata, 0, usize);
if (ioctl->flags & DRM_UNLOCKED)
retcode = func(dev, kdata, file_priv);
else {
mutex_lock(&drm_global_mutex);
retcode = func(dev, kdata, file_priv);
mutex_unlock(&drm_global_mutex);
}
if (cmd & IOC_OUT) {
if (copy_to_user((void __user *)arg, kdata,
usize) != 0)
retcode = -EFAULT;
}
err_i1: