Return-Path: Received: from mail-io0-f193.google.com ([209.85.223.193]:35226 "EHLO mail-io0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933710AbcK2QEg (ORCPT ); Tue, 29 Nov 2016 11:04:36 -0500 Subject: [PATCH v3 02/10] svcauth_gss: Close connection when dropping an incoming message From: Chuck Lever To: bfields@fieldses.org Cc: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Tue, 29 Nov 2016 11:04:34 -0500 Message-ID: <20161129160434.4477.76542.stgit@klimt.1015granger.net> In-Reply-To: <20161129155521.4477.53561.stgit@klimt.1015granger.net> References: <20161129155521.4477.53561.stgit@klimt.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: S5.3.3.1 of RFC 2203 requires that an incoming GSS-wrapped message whose sequence number lies outside the current window is dropped. The rationale is: The reason for discarding requests silently is that the server is unable to determine if the duplicate or out of range request was due to a sequencing problem in the client, network, or the operating system, or due to some quirk in routing, or a replay attack by an intruder. Discarding the request allows the client to recover after timing out, if indeed the duplication was unintentional or well intended. However, clients may rely on the server dropping the connection to indicate that a retransmit is needed. Without a connection reset, a client can wait forever without retransmitting, and the workload just stops dead. I've reproduced this behavior by running xfstests generic/323 on an NFSv4.0 mount with proto=rdma and sec=krb5i. To address this issue, have the server close the connection when it silently discards an incoming message due to a GSS sequence number problem. There are a few other places where the server will never reply. Change those spots in a similar fashion. Signed-off-by: Chuck Lever --- net/sunrpc/auth_gss/svcauth_gss.c | 2 +- net/sunrpc/svc.c | 14 +++++++++----- 2 files changed, 10 insertions(+), 6 deletions(-) diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index 45662d7..886e9d38 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -1548,7 +1548,7 @@ static void destroy_use_gss_proxy_proc_entry(struct net *net) {} ret = SVC_COMPLETE; goto out; drop: - ret = SVC_DROP; + ret = SVC_CLOSE; out: if (rsci) cache_put(&rsci->h, sn->rsc_cache); diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index 7c8070e..75f290b 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -1155,8 +1155,7 @@ static __printf(2,3) void svc_printk(struct svc_rqst *rqstp, const char *fmt, .. case SVC_DENIED: goto err_bad_auth; case SVC_CLOSE: - if (test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags)) - svc_close_xprt(rqstp->rq_xprt); + goto close; case SVC_DROP: goto dropit; case SVC_COMPLETE: @@ -1246,7 +1245,7 @@ static __printf(2,3) void svc_printk(struct svc_rqst *rqstp, const char *fmt, .. sendit: if (svc_authorise(rqstp)) - goto dropit; + goto close; return 1; /* Caller can now send it */ dropit: @@ -1254,11 +1253,16 @@ static __printf(2,3) void svc_printk(struct svc_rqst *rqstp, const char *fmt, .. dprintk("svc: svc_process dropit\n"); return 0; + close: + if (test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags)) + svc_close_xprt(rqstp->rq_xprt); + dprintk("svc: svc_process close\n"); + return 0; + err_short_len: svc_printk(rqstp, "short len %Zd, dropping request\n", argv->iov_len); - - goto dropit; /* drop request */ + goto close; err_bad_rpc: serv->sv_stats->rpcbadfmt++;