Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1638013

Re: [PATCH 3/9] VFS: Introduce a mount context

From David Howells <dhowells@redhat.com>
Newsgroups linux.kernel
Subject Re: [PATCH 3/9] VFS: Introduce a mount context
Date 2017-05-09 11:50 +0200
Message-ID <tF9Wi-8nt-9@gated-at.bofh.it> (permalink)
References (1 earlier) <tD50J-7GP-3@gated-at.bofh.it> <tD50K-7GP-19@gated-at.bofh.it> <tESsq-5wT-33@gated-at.bofh.it> <tEZNf-1D3-7@gated-at.bofh.it> <tF8nv-7up-3@gated-at.bofh.it>
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

Show all headers | View raw

Miklos Szeredi <mszeredi@redhat.com> wrote:

> I think that's crazy.  We don't return detailed errors for any other
> syscall for path lookup, so why would path lookup for mount be
> special.

Firstly, we don't return detailed errors for mount() at the moment either.

Secondly, path lookup might entail automounts, so perhaps we should do it for
path lookup too.  Particularly in light of the fact that NFS4 mount uses
pathwalk to get from server:/ to server:/the/dir/I/actually/wanted/ so I'm
currently losing that error:-/

Thirdly, the security operation I'm talking about is separate to path lookup -
though perhaps we should pass LOOKUP_MOUNT as an intent flag into pathwalk so
that the security check can be done there; perhaps combined with another one.

Fourthly, why shouldn't we consider extending the facility to other system
calls in future?  It would involve copying the string to task_struct and
providing a way to retrieve it, but that's not that hard to achieve.

> And why would
> 
>     fd = open("/foo/bar", O_PATH);
>     fsmount(fsfd, fd, NULL);
> 
> behave differently from
> 
>     fsmount(fsfd, -1, "/foo/bar");
> 
> ?

There's argument that the former should return EFAULT.  And that you should
set the path to "" and pass AT_EMPTY_PATH.  I should probably make sure it
does that - and add a flags field.  statx() was fixed to work this way.

Question for you: Should the MNT_* flags be passed to fsmount(), perhaps in
MS_* form?

David

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[RFC][PATCH 0/9] VFS: Introduce mount context David Howells <dhowells@redhat.com> - 2017-05-03 18:10 +0200
  [PATCH 1/9] Provide a function to create a NUL-terminated string  from unterminated data David Howells <dhowells@redhat.com> - 2017-05-03 18:10 +0200
    Re: [PATCH 1/9] Provide a function to create a NUL-terminated  string from unterminated data Jeff Layton <jlayton@poochiereds.net> - 2017-05-03 19:00 +0200
    Re: [PATCH 1/9] Provide a function to create a NUL-terminated string from unterminated data Rasmus Villemoes <linux@rasmusvillemoes.dk> - 2017-05-03 21:30 +0200
      Re: [PATCH 1/9] Provide a function to create a NUL-terminated string from unterminated data David Howells <dhowells@redhat.com> - 2017-05-03 22:20 +0200
  [PATCH 4/9] Implement fsopen() to prepare for a mount David Howells <dhowells@redhat.com> - 2017-05-03 18:10 +0200
    Re: [PATCH 4/9] Implement fsopen() to prepare for a mount Jeff Layton <jlayton@poochiereds.net> - 2017-05-03 20:40 +0200
      Re: [PATCH 4/9] Implement fsopen() to prepare for a mount David Howells <dhowells@redhat.com> - 2017-05-03 20:50 +0200
    Re: [PATCH 4/9] Implement fsopen() to prepare for a mount Rasmus Villemoes <linux@rasmusvillemoes.dk> - 2017-05-03 22:50 +0200
      Re: [PATCH 4/9] Implement fsopen() to prepare for a mount David Howells <dhowells@redhat.com> - 2017-05-04 15:00 +0200
      Re: [PATCH 4/9] Implement fsopen() to prepare for a mount David Howells <dhowells@redhat.com> - 2017-05-04 15:00 +0200
    Re: [PATCH 4/9] Implement fsopen() to prepare for a mount Karel Zak <kzak@redhat.com> - 2017-05-04 12:50 +0200
      Re: [PATCH 4/9] Implement fsopen() to prepare for a mount David Howells <dhowells@redhat.com> - 2017-05-04 15:10 +0200
        Re: [PATCH 4/9] Implement fsopen() to prepare for a mount Karel Zak <kzak@redhat.com> - 2017-05-04 15:40 +0200
          Re: [PATCH 4/9] Implement fsopen() to prepare for a mount Jeff Layton <jlayton@redhat.com> - 2017-05-09 20:50 +0200
    Re: [PATCH 4/9] Implement fsopen() to prepare for a mount Miklos Szeredi <mszeredi@redhat.com> - 2017-05-08 17:20 +0200
      Re: [PATCH 4/9] Implement fsopen() to prepare for a mount David Howells <dhowells@redhat.com> - 2017-05-09 01:20 +0200
  [PATCH 5/9] Implement fsmount() to effect a pre-configured mount David Howells <dhowells@redhat.com> - 2017-05-03 18:10 +0200
  [PATCH 2/9] Clean up whitespace in fs/namespace.c David Howells <dhowells@redhat.com> - 2017-05-03 18:10 +0200
  [PATCH 8/9] proc: Support the mount context in procfs David Howells <dhowells@redhat.com> - 2017-05-03 18:10 +0200
  [PATCH 7/9] procfs: Move proc_fill_super() to fs/proc/root.c David Howells <dhowells@redhat.com> - 2017-05-03 18:10 +0200
  Re: [RFC][PATCH 0/9] VFS: Introduce mount context Jeff Layton <jlayton@poochiereds.net> - 2017-05-03 18:50 +0200
    Re: [RFC][PATCH 0/9] VFS: Introduce mount context David Howells <dhowells@redhat.com> - 2017-05-03 19:00 +0200
      Re: [RFC][PATCH 0/9] VFS: Introduce mount context Jeff Layton <jlayton@poochiereds.net> - 2017-05-03 19:30 +0200
  Re: [PATCH 3/9] VFS: Introduce a mount context Joe Perches <joe@perches.com> - 2017-05-03 20:30 +0200
    Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-03 20:40 +0200
      Re: [PATCH 3/9] VFS: Introduce a mount context Joe Perches <joe@perches.com> - 2017-05-03 20:50 +0200
        Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-03 22:20 +0200
    Re: [PATCH 3/9] VFS: Introduce a mount context Matthew Wilcox <willy@infradead.org> - 2017-05-03 22:40 +0200
      Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-03 23:20 +0200
      Re: [PATCH 3/9] VFS: Introduce a mount context Joe Perches <joe@perches.com> - 2017-05-03 23:40 +0200
        Re: [PATCH 3/9] VFS: Introduce a mount context Julia Lawall <julia.lawall@lip6.fr> - 2017-05-04 08:30 +0200
    Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-04 11:30 +0200
      Re: [PATCH 3/9] VFS: Introduce a mount context Joe Perches <joe@perches.com> - 2017-05-04 16:40 +0200
  Re: [PATCH 3/9] VFS: Introduce a mount context Rasmus Villemoes <linux@rasmusvillemoes.dk> - 2017-05-03 23:50 +0200
    Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-04 12:30 +0200
  Re: [RFC][PATCH 0/9] VFS: Introduce mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-05 16:40 +0200
    Re: [RFC][PATCH 0/9] VFS: Introduce mount context David Howells <dhowells@redhat.com> - 2017-05-05 17:50 +0200
      Re: [RFC][PATCH 0/9] VFS: Introduce mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-08 10:30 +0200
      Re: [RFC][PATCH 0/9] VFS: Introduce mount context David Howells <dhowells@redhat.com> - 2017-05-08 10:40 +0200
        Re: [RFC][PATCH 0/9] VFS: Introduce mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-08 10:50 +0200
  Re: [PATCH 3/9] VFS: Introduce a mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-08 17:10 +0200
    Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-09 01:00 +0200
      Re: [PATCH 3/9] VFS: Introduce a mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-09 10:10 +0200
        Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-09 11:40 +0200
          Re: [PATCH 3/9] VFS: Introduce a mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-09 13:10 +0200
        Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-09 11:50 +0200
          Re: [PATCH 3/9] VFS: Introduce a mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-09 14:10 +0200
            Re: [PATCH 3/9] VFS: Introduce a mount context Jeff Layton <jlayton@redhat.com> - 2017-05-09 21:00 +0200
              Re: [PATCH 3/9] VFS: Introduce a mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-10 09:30 +0200
                Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-10 10:10 +0200
                Re: [PATCH 3/9] VFS: Introduce a mount context Jeff Layton <jlayton@redhat.com> - 2017-05-10 15:30 +0200
                Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-10 15:40 +0200
                Re: [PATCH 3/9] VFS: Introduce a mount context Jeff Layton <jlayton@redhat.com> - 2017-05-10 15:40 +0200
                Re: [PATCH 3/9] VFS: Introduce a mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-10 15:40 +0200
                Re: [PATCH 3/9] VFS: Introduce a mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-10 15:40 +0200
                Re: [PATCH 3/9] VFS: Introduce a mount context Jeff Layton <jlayton@redhat.com> - 2017-05-10 15:50 +0200
        Re: [PATCH 3/9] VFS: Introduce a mount context David Howells <dhowells@redhat.com> - 2017-05-09 12:00 +0200
          Re: [PATCH 3/9] VFS: Introduce a mount context Miklos Szeredi <mszeredi@redhat.com> - 2017-05-09 14:40 +0200
        Re: [PATCH 3/9] VFS: Introduce a mount context Karel Zak <kzak@redhat.com> - 2017-05-10 14:50 +0200
  Re: [RFC][PATCH 0/9] VFS: Introduce mount context Djalal Harouni <tixxdz@gmail.com> - 2017-05-08 19:10 +0200

csiph-web