# Re: \[PATCH\] statx: reject unknown flags when using NULL path

- From: Christoph Hellwig \<hch@infradead.org\>
- Date: 2017-03-20 17:44:29 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2017/03/119329
- Thread: https://ratatoskr.run/linux-fsdevel/2017/03/119331/t.md

```text
On Mon, Mar 20, 2017 at 10:11:42AM -0700, Eric Biggers wrote:
> On Fri, Mar 10, 2017 at 10:58:23PM -0800, Eric Biggers wrote:
> > From: Eric Biggers <redacted>
> > 
> > The statx() system call currently accepts unknown flags when called with
> > a NULL path to operate on a file descriptor.  Left unchanged, this could
> > make it hard to introduce new query flags in the future, since
> > applications may not be able to tell whether a given flag is supported.
> > 
> > Fix this by failing the system call with EINVAL if any flags other than
> > KSTAT_QUERY_FLAGS are specified in combination with a NULL path.
> > 
> 
> Does anyone have comments on this patch?

Looks good to me.

> I really think we need to get this in before v4.11 is released, since it deals
> with the API.

Yes.  And we really need test for all of this.  Or just revert the
patches.  Shipping with untested syscalls is just a desaster.
```