MIME-Version: 1.0
In-Reply-To: <CAN-5tyGWFYp-dU=8Prpmyyr=B=Z3jAfiO_qs0-KfC_xvDwUMaA@mail.gmail.com>
References: <CAN-5tyGWFYp-dU=8Prpmyyr=B=Z3jAfiO_qs0-KfC_xvDwUMaA@mail.gmail.com>
From: Olga Kornievskaia <aglo@umich.edu>
Date: Thu, 2 Mar 2017 14:44:00 -0500
Message-ID: <CAN-5tyHFZVd=o0SOw3ZoXk8w8WWKqoQdMPcXDq2nzXncBkJamg@mail.gmail.com>
Subject: Re: changing error message for mount failure
To: linux-nfs <linux-nfs@vger.kernel.org>
Content-Type: text/plain; charset=UTF-8
Sender: linux-nfs-owner@vger.kernel.org

On Tue, Feb 21, 2017 at 4:43 PM, Olga Kornievskaia <aglo@umich.edu> wrote:
> In the upstream kernel when doing the mount without specifying the
> security flavor and the server returning EACCES to the
> PUTROOTFH|GETATTR, the code ends up translating this to EPERM which
> mount fails with "Operation not permitted". Doing the same mount, but
> specifying "sec=sys" on the command line translates to the "Access
> denied" error. While not too terrible, it's just a bit inconsistent.
>
> Anna pointed me to this discussion
> https://lists.gt.net/linux/kernel/1366207#1366207 that was possibly
> the reason for the translation of EACCES to EPERM in
> nfs4_find_root_sec().
>
> Is this still a needed correction? I tried: no gssd running and asking
> for a krb5 mount and it leads to "an incorrect mount option was
> specified" (EINVAL returned by nfs).
>
> I propose to remove it to address the difference in error messages for EACCES:
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index d293f06..a03f587 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -3576,15 +3576,6 @@ static int nfs4_find_root_sec(struct nfs_server
> *server, struct nfs_fh *fhandle,
>   }
>   }
>
> - /*
> - * -EACCESS could mean that the user doesn't have correct permissions
> - * to access the mount.  It could also mean that we tried to mount
> - * with a gss auth flavor, but rpc.gssd isn't running.  Either way,
> - * existing mount programs don't handle -EACCES very well so it should
> - * be mapped to -EPERM instead.
> - */
> - if (status == -EACCES)
> - status = -EPERM;
>   return status;
>  }

Any comments about the suggested change would be appreciated.