Return-Path: Received: from mx2.suse.de ([195.135.220.15]:55470 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750932AbdHRHOY (ORCPT ); Fri, 18 Aug 2017 03:14:24 -0400 From: NeilBrown To: Trond Myklebust , Anna Schumaker Date: Fri, 18 Aug 2017 17:12:52 +1000 Subject: [PATCH 8/8] NFSv4.1: don't use machine credentials for CLOSE when using 'sec=sys' Cc: linux-nfs@vger.kernel.org Message-ID: <150304037211.30218.1236272488580678069.stgit@noble> In-Reply-To: <150304014011.30218.1636255532744321171.stgit@noble> References: <150304014011.30218.1636255532744321171.stgit@noble> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: An NFSv4.1 client might close a file after the user who opened it has logged off. In this case the user's credentials may no longer be valid, if they are e.g. kerberos credentials that have expired. NFSv4.1 has a mechanism to allow the client to use machine credentials to close a file. However due to a short-coming in the RFC, a CLOSE with those credentials may not be possible if the file in question isn't exported to the same security flavor - the required PUTFH must be rejected when this is the case. Specifically if a server and client support kerberos in general and have used it to form a machine credential, but the file is only exported to "sec=sys", a PUTFH with the machine credentials will fail, so CLOSE is not possible. As RPC_AUTH_UNIX (used by sec=sys) credentials can never expire, there is no value in using the machine credential in place of them. So in that case, just use the users credentials for CLOSE etc, as you would in NFSv4.0 Signed-off-by: Neil Brown Signed-off-by: NeilBrown --- fs/nfs/nfs4_fs.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h index 40bd05f05e74..ac4f10b7f6c1 100644 --- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -303,6 +303,17 @@ _nfs4_state_protect(struct nfs_client *clp, unsigned long sp4_mode, struct rpc_cred *newcred = NULL; rpc_authflavor_t flavor; + if (sp4_mode == NFS_SP4_MACH_CRED_CLEANUP || + sp4_mode == NFS_SP4_MACH_CRED_PNFS_CLEANUP) { + /* Using machine creds for cleanup operations + * is only relevent if the client credentials + * might expire. So don't bother for + * RPC_AUTH_UNIX. If file was only exported to + * sec=sys, the PUTFH would fail anyway. + */ + if ((*clntp)->cl_auth->au_flavor == RPC_AUTH_UNIX) + return false; + } if (test_bit(sp4_mode, &clp->cl_sp4_flags)) { spin_lock(&clp->cl_lock); if (clp->cl_machine_cred != NULL)