Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley
        Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United
        Kingdom.
        Registered in England and Wales under Company Registration No. 3798903
From:   David Howells <dhowells@redhat.com>
In-Reply-To: <20200302143546.srzk3rnh4o6s76a7@wittgenstein>
References: <20200302143546.srzk3rnh4o6s76a7@wittgenstein> <20200302115239.pcxvej3szmricxzu@wittgenstein> <96563.1582901612@warthog.procyon.org.uk> <20200228152427.rv3crd7akwdhta2r@wittgenstein> <87h7z7ngd4.fsf@oldenburg2.str.redhat.com> <848282.1583159228@warthog.procyon.org.uk>
To:     Christian Brauner <christian.brauner@ubuntu.com>
Cc:     dhowells@redhat.com, Florian Weimer <fweimer@redhat.com>,
        linux-api@vger.kernel.org, viro@zeniv.linux.org.uk,
        metze@samba.org, torvalds@linux-foundation.org, cyphar@cyphar.com,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Have RESOLVE_* flags superseded AT_* flags for new syscalls?
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <888182.1583160603.1@warthog.procyon.org.uk>
Date:   Mon, 02 Mar 2020 14:50:03 +0000
Message-ID: <888183.1583160603@warthog.procyon.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Christian Brauner <christian.brauner@ubuntu.com> wrote:

> 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().

Say, for example, my home dir is on a network volume somewhere and /home has a
symlink pointing to it.  RESOLVE_NO_SYMLINKS cannot be used to access a file
inside my homedir if the pathwalk would go through /home/dhowells - this would
affect fsinfo() - so RESOLVE_NO_SYMLINKS is not a substitute for
AT_SYMLINK_NOFOLLOW (O_NOFOLLOW would not come into it).

David