Re: Have RESOLVE_* flags superseded AT_* flags for new syscalls?

Christian Brauner
2020-03-02T14:35:52Z

On Mon, Mar 02, 2020 at 02:27:08PM +0000, David Howells wrote:
> Christian Brauner <christian.brauner@ubuntu.com> wrote:
>
> > > AT_SYMLINK_NOFOLLOW only applies to the last pathname component anyway,
> > > so it's relatively little protection.
> >
> > So this is partially why I think it's at least worth considerings: the
> > new RESOLVE_NO_SYMLINKS flag does block all symlink resolution, not just
> > for the last component in contrast to AT_SYMLINK_NOFOLLOW. This is
> > 278121417a72d87fb29dd8c48801f80821e8f75a
>
> That sounds like a potentially significant UAPI change. What will that break?

I think we settled this and can agree on RESOLVE_NO_SYMLINKS being the
right thing to do, i.e. not resolving symlinks will stay opt-in.
Or is your worry even with the current semantics of openat2()? I don't
see the issue since O_NOFOLLOW still works with openat2().

Christian