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: <CAHk-=wiEBNFJ0_riJnpuUXTO7+_HByVo-R3pGoB_84qv3LzHxA@mail.gmail.com>
References: <CAHk-=wiEBNFJ0_riJnpuUXTO7+_HByVo-R3pGoB_84qv3LzHxA@mail.gmail.com> <158376244589.344135.12925590041630631412.stgit@warthog.procyon.org.uk> <158376245699.344135.7522994074747336376.stgit@warthog.procyon.org.uk> <20200310005549.adrn3yf4mbljc5f6@yavin>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     dhowells@redhat.com, Aleksa Sarai <cyphar@cyphar.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Stefan Metzmacher <metze@samba.org>,
        Ian Kent <raven@themaw.net>,
        Miklos Szeredi <mszeredi@redhat.com>,
        Christian Brauner <christian@brauner.io>,
        Jann Horn <jannh@google.com>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Karel Zak <kzak@redhat.com>, jlayton@redhat.com,
        Linux API <linux-api@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        LSM List <linux-security-module@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 01/14] VFS: Add additional RESOLVE_* flags [ver #18]
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <580351.1583825105.1@warthog.procyon.org.uk>
Date:   Tue, 10 Mar 2020 07:25:05 +0000
Message-ID: <580352.1583825105@warthog.procyon.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Linus Torvalds <torvalds@linux-foundation.org> wrote:

> > > Also make openat2() handle RESOLVE_NO_TRAILING_SYMLINKS.
> 
> No, please let's not do this.
> 
> We have O_NOFOLLOW, and we can't get rid of it.
> 
> So adding RESOLVE_NO_TRAILING_SYMLINKS isn't a cleanup. It's just
> extra complexity for absolutely zero gain.

Okay.  So what's the equivalent of AT_SYMLINK_NOFOLLOW in RESOLVE_* flag
terms?  RESOLVE_NO_SYMLINKS is not equivalent, though O_NOFOLLOW is.  The
reason I ask is that RESOLVE_* flags can't be easily extended to non-open
syscalls that don't take O_* flags without it.  Would you prefer that new
non-open syscalls continue to take AT_* and ignore RESOLVE_* flags?  That
would be fine by me.

David