On Fri, 2013-06-07 at 15:45 -0400, Chuck Lever wrote:
> Commit 05f4c350 "NFS: Discover NFSv4 server trunking when mounting"
> Fri Sep 14 17:24:32 2012 introduced Uniform Client String support,
> which forces our NFS client to establish a client ID immediately
> during a mount operation rather than waiting until a user wants to
> open a file.
>
> Normally machine credentials (eg. from a keytab) are used to perform
> a mount operation that is protected by Kerberos. Before 05fc350,
> SETCLIENTID used a machine credential, or fell back to a regular
> user's credential if no keytab is available.
>
> On clients that don't have a keytab, performing SETCLIENTID early
> means there's no user credential to fall back on, since no regular
> user has kinit'd yet. 05f4c350 seems to have broken the ability
> to mount with sec=krb5 on clients that don't have a keytab in
> kernels 3.7 - 3.9.
>
> To address this regression, commit 4edaa308 (NFS: Use "krb5i" to
> establish NFSv4 state whenever possible), Sat Mar 16 15:56:20 2013,
> was merged in 3.10. This commit forces the NFS client to fall back
> to AUTH_SYS for lease management operations if no keytab is
> available.
>
> Neil Brown noticed that, since root is required to kinit to do a
> sec=krb5 mount when a client doesn't have a keytab, we can try to
> use root's Kerberos credential before AUTH_SYS.
>
> Now, when determining a principal and flavor to use for lease
> management, the NFS client tries in this order:
>
> 1. Flavor: AUTH_GSS, krb5i
> Principal: service principal (via keytab)
>
> 2. Flavor: AUTH_GSS, krb5i
> Principal: user principal established for UID 0 (via kinit)
>
> 3. Flavor: AUTH_SYS
> Principal: UID 0 / GID 0
>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
> fs/nfs/nfs4proc.c | 21 ++++++++++++++-------
> fs/nfs/nfs4state.c | 16 ++++++++--------
> 2 files changed, 22 insertions(+), 15 deletions(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 5ba38b3..4d76fae 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -4356,7 +4356,8 @@ int nfs4_proc_setclientid(struct nfs_client *clp, u32 program,
> dprintk("NFS call setclientid auth=%s, '%.*s'\n",
> clp->cl_rpcclient->cl_auth->au_ops->au_name,
> setclientid.sc_name_len, setclientid.sc_name);
> - status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
> + status = rpc_call_sync(clp->cl_rpcclient, &msg,
> + RPC_TASK_TIMEOUT|RPC_TASK_ROOTCREDS);
We are certainly _not_ resurrecting the RPC_TASK_ROOTCREDS abomination.
For one thing is overrides the machine creds that are what we really
want to use when available.
NACK...
> dprintk("NFS reply setclientid: %d\n", status);
> return status;
> }
> @@ -4383,7 +4384,8 @@ int nfs4_proc_setclientid_confirm(struct nfs_client *clp,
> dprintk("NFS call setclientid_confirm auth=%s, (client ID %llx)\n",
> clp->cl_rpcclient->cl_auth->au_ops->au_name,
> clp->cl_clientid);
> - status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
> + status = rpc_call_sync(clp->cl_rpcclient, &msg,
> + RPC_TASK_TIMEOUT|RPC_TASK_ROOTCREDS);
> dprintk("NFS reply setclientid_confirm: %d\n", status);
> return status;
> }
> @@ -5461,7 +5463,8 @@ int nfs4_proc_bind_conn_to_session(struct nfs_client *clp, struct rpc_cred *cred
> goto out;
> }
>
> - status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
> + status = rpc_call_sync(clp->cl_rpcclient, &msg,
> + RPC_TASK_TIMEOUT|RPC_TASK_ROOTCREDS);
> if (status == 0) {
> if (memcmp(res.session->sess_id.data,
> clp->cl_session->sess_id.data, NFS4_MAX_SESSIONID_LEN)) {
> @@ -5545,7 +5548,8 @@ int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
> goto out_server_scope;
> }
>
> - status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
> + status = rpc_call_sync(clp->cl_rpcclient, &msg,
> + RPC_TASK_TIMEOUT|RPC_TASK_ROOTCREDS);
> if (status == 0)
> status = nfs4_check_cl_exchange_flags(res.flags);
>
> @@ -5605,7 +5609,8 @@ static int _nfs4_proc_destroy_clientid(struct nfs_client *clp,
> };
> int status;
>
> - status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
> + status = rpc_call_sync(clp->cl_rpcclient, &msg,
> + RPC_TASK_TIMEOUT|RPC_TASK_ROOTCREDS);
> if (status)
> dprintk("NFS: Got error %d from the server %s on "
> "DESTROY_CLIENTID.", status, clp->cl_hostname);
> @@ -5871,7 +5876,8 @@ static int _nfs4_proc_create_session(struct nfs_client *clp,
> nfs4_init_channel_attrs(&args);
> args.flags = (SESSION4_PERSIST | SESSION4_BACK_CHAN);
>
> - status = rpc_call_sync(session->clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
> + status = rpc_call_sync(session->clp->cl_rpcclient, &msg,
> + RPC_TASK_TIMEOUT|RPC_TASK_ROOTCREDS);
>
> if (!status) {
> /* Verify the session's negotiated channel_attrs values */
> @@ -5934,7 +5940,8 @@ int nfs4_proc_destroy_session(struct nfs4_session *session,
> if (session->clp->cl_cons_state != NFS_CS_READY)
> return status;
>
> - status = rpc_call_sync(session->clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
> + status = rpc_call_sync(session->clp->cl_rpcclient, &msg,
> + RPC_TASK_TIMEOUT|RPC_TASK_ROOTCREDS);
>
> if (status)
> dprintk("NFS: Got error %d from the server on DESTROY_SESSION. "
> diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
> index 4949ce5..d8068ab 100644
> --- a/fs/nfs/nfs4state.c
> +++ b/fs/nfs/nfs4state.c
> @@ -1811,10 +1811,9 @@ static int nfs4_establish_lease(struct nfs_client *clp)
> int status;
>
> cred = ops->get_clid_cred(clp);
> - if (cred == NULL)
> - return -ENOENT;
> status = ops->establish_clid(clp, cred);
> - put_rpccred(cred);
> + if (cred)
> + put_rpccred(cred);
> if (status != 0)
> return status;
> pnfs_destroy_all_layouts(clp);
> @@ -1885,11 +1884,9 @@ int nfs4_discover_server_trunking(struct nfs_client *clp,
> again:
> status = -ENOENT;
> cred = ops->get_clid_cred(clp);
> - if (cred == NULL)
> - goto out_unlock;
> -
> status = ops->detect_trunking(clp, result, cred);
> - put_rpccred(cred);
> + if (cred)
> + put_rpccred(cred);
> switch (status) {
> case 0:
> break;
> @@ -1902,6 +1899,10 @@ again:
> __func__, status);
> goto again;
> case -EACCES:
> + if (clp->cl_machine_cred != NULL) {
> + nfs4_clear_machine_cred(clp);
> + goto again;
> + }
> if (i++)
> break;
> case -NFS4ERR_CLID_INUSE:
> @@ -1935,7 +1936,6 @@ again:
> status = -EIO;
> }
>
> -out_unlock:
> mutex_unlock(&nfs_clid_init_mutex);
> dprintk("NFS: %s: status = %d\n", __func__, status);
> return status;
>
> --
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--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
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