Merge tag 'nfsd-4.11' of git://linux-nfs.org/~bfields/linux

Pull nfsd updates from Bruce Fields:
 "The nfsd update this round is mainly a lot of miscellaneous cleanups
  and bugfixes.

  A couple changes could theoretically break working setups on upgrade.
  I don't expect complaints in practice, but they seem worth calling out
  just in case:

   - NFS security labels are now off by default; a new security_label
     export flag reenables it per export. But, having them on by default
     is a disaster, as it generally only makes sense if all your clients
     and servers have similar enough selinux policies. Thanks to Jason
     Tibbitts for pointing this out.

   - NFSv4/UDP support is off. It was never really supported, and the
     spec explicitly forbids it. We only ever left it on out of
     laziness; thanks to Jeff Layton for finally fixing that"

* tag 'nfsd-4.11' of git://linux-nfs.org/~bfields/linux: (34 commits)
  nfsd: Fix display of the version string
  nfsd: fix configuration of supported minor versions
  sunrpc: don't register UDP port with rpcbind when version needs congestion control
  nfs/nfsd/sunrpc: enforce transport requirements for NFSv4
  sunrpc: flag transports as having congestion control
  sunrpc: turn bitfield flags in svc_version into bools
  nfsd: remove superfluous KERN_INFO
  nfsd: special case truncates some more
  nfsd: minor nfsd_setattr cleanup
  NFSD: Reserve adequate space for LOCKT operation
  NFSD: Get response size before operation for all RPCs
  nfsd/callback: Drop a useless data copy when comparing sessionid
  nfsd/callback: skip the callback tag
  nfsd/callback: Cleanup callback cred on shutdown
  nfsd/idmap: return nfserr_inval for 0-length names
  SUNRPC/Cache: Always treat the invalid cache as unexpired
  SUNRPC: Drop all entries from cache_detail when cache_purge()
  svcrdma: Poll CQs in "workqueue" mode
  svcrdma: Combine list fields in struct svc_rdma_op_ctxt
  svcrdma: Remove unused sc_dto_q field
  ...

1 files changed, 23 insertions, 1 deletions

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 2e22889a8837..b94efd93d3e4 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -385,7 +385,7 @@ static int svc_uses_rpcbind(struct svc_serv *serv)
 		for (i = 0; i < progp->pg_nvers; i++) {
 			if (progp->pg_vers[i] == NULL)
 				continue;
-			if (progp->pg_vers[i]->vs_hidden == 0)
+			if (!progp->pg_vers[i]->vs_hidden)
 				return 1;
 		}
 	}
@@ -976,6 +976,13 @@ int svc_register(const struct svc_serv *serv, struct net *net,
 			if (vers->vs_hidden)
 				continue;
 
+			/*
+			 * Don't register a UDP port if we need congestion
+			 * control.
+			 */
+			if (vers->vs_need_cong_ctrl && proto == IPPROTO_UDP)
+				continue;
+
 			error = __svc_register(net, progp->pg_name, progp->pg_prog,
 						i, family, proto, port);
 
@@ -1169,6 +1176,21 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 	  !(versp = progp->pg_vers[vers]))
 		goto err_bad_vers;
 
+	/*
+	 * Some protocol versions (namely NFSv4) require some form of
+	 * congestion control.  (See RFC 7530 section 3.1 paragraph 2)
+	 * In other words, UDP is not allowed. We mark those when setting
+	 * up the svc_xprt, and verify that here.
+	 *
+	 * The spec is not very clear about what error should be returned
+	 * when someone tries to access a server that is listening on UDP
+	 * for lower versions. RPC_PROG_MISMATCH seems to be the closest
+	 * fit.
+	 */
+	if (versp->vs_need_cong_ctrl &&
+	    !test_bit(XPT_CONG_CTRL, &rqstp->rq_xprt->xpt_flags))
+		goto err_bad_vers;
+
 	procp = versp->vs_proc + proc;
 	if (proc >= versp->vs_nproc || !procp->pc_func)
 		goto err_bad_proc;