Implement support for RPCSEC_GSS authentication to both the NFS client

and server. This replaces the RPC implementation of the NFS client and
server with the newer RPC implementation originally developed
(actually ported from the userland sunrpc code) to support the NFS
Lock Manager.  I have tested this code extensively and I believe it is
stable and that performance is at least equal to the legacy RPC
implementation.

The NFS code currently contains support for both the new RPC
implementation and the older legacy implementation inherited from the
original NFS codebase. The default is to use the new implementation -
add the NFS_LEGACYRPC option to fall back to the old code. When I
merge this support back to RELENG_7, I will probably change this so
that users have to 'opt in' to get the new code.

To use RPCSEC_GSS on either client or server, you must build a kernel
which includes the KGSSAPI option and the crypto device. On the
userland side, you must build at least a new libc, mountd, mount_nfs
and gssd. You must install new versions of /etc/rc.d/gssd and
/etc/rc.d/nfsd and add 'gssd_enable=YES' to /etc/rc.conf.

As long as gssd is running, you should be able to mount an NFS
filesystem from a server that requires RPCSEC_GSS authentication. The
mount itself can happen without any kerberos credentials but all
access to the filesystem will be denied unless the accessing user has
a valid ticket file in the standard place (/tmp/krb5cc_<uid>). There
is currently no support for situations where the ticket file is in a
different place, such as when the user logged in via SSH and has
delegated credentials from that login. This restriction is also
present in Solaris and Linux. In theory, we could improve this in
future, possibly using Brooks Davis' implementation of variant
symlinks.

Supporting RPCSEC_GSS on a server is nearly as simple. You must create
service creds for the server in the form 'nfs/<fqdn>@<REALM>' and
install them in /etc/krb5.keytab. The standard heimdal utility ktutil
makes this fairly easy. After the service creds have been created, you
can add a '-sec=krb5' option to /etc/exports and restart both mountd
and nfsd.

The only other difference an administrator should notice is that nfsd
doesn't fork to create service threads any more. In normal operation,
there will be two nfsd processes, one in userland waiting for TCP
connections and one in the kernel handling requests. The latter
process will create as many kthreads as required - these should be
visible via 'top -H'. The code has some support for varying the number
of service threads according to load but initially at least, nfsd uses
a fixed number of threads according to the value supplied to its '-n'
option.

Sponsored by:	Isilon Systems
MFC after:	1 month

1 files changed, 53 insertions, 28 deletions

diff --git a/sys/rpc/rpc_prot.c b/sys/rpc/rpc_prot.c
index 16f602f..294c4e3 100644
--- a/sys/rpc/rpc_prot.c
+++ b/sys/rpc/rpc_prot.c
@@ -64,8 +64,8 @@ MALLOC_DEFINE(M_RPC, "rpc", "Remote Procedure Call");
 
 #define assert(exp)	KASSERT(exp, ("bad arguments"))
 
-static void accepted(enum accept_stat, struct rpc_err *);
-static void rejected(enum reject_stat, struct rpc_err *);
+static enum clnt_stat accepted(enum accept_stat, struct rpc_err *);
+static enum clnt_stat rejected(enum reject_stat, struct rpc_err *);
 
 /* * * * * * * * * * * * * * XDR Authentication * * * * * * * * * * * */
 
@@ -111,7 +111,11 @@ xdr_accepted_reply(XDR *xdrs, struct accepted_reply *ar)
 	switch (ar->ar_stat) {
 
 	case SUCCESS:
-		return ((*(ar->ar_results.proc))(xdrs, ar->ar_results.where));
+		if (ar->ar_results.proc != (xdrproc_t) xdr_void)
+			return ((*(ar->ar_results.proc))(xdrs,
+				ar->ar_results.where));
+		else
+			return (TRUE);
 
 	case PROG_MISMATCH:
 		if (! xdr_uint32_t(xdrs, &(ar->ar_vers.low)))
@@ -171,12 +175,34 @@ static const struct xdr_discrim reply_dscrm[3] = {
 bool_t
 xdr_replymsg(XDR *xdrs, struct rpc_msg *rmsg)
 {
+	int32_t *buf;
 	enum msg_type *prm_direction;
 	enum reply_stat *prp_stat;
 
 	assert(xdrs != NULL);
 	assert(rmsg != NULL);
 
+	if (xdrs->x_op == XDR_DECODE) {
+		buf = XDR_INLINE(xdrs, 3 * BYTES_PER_XDR_UNIT);
+		if (buf != NULL) {
+			rmsg->rm_xid = IXDR_GET_UINT32(buf);
+			rmsg->rm_direction = IXDR_GET_ENUM(buf, enum msg_type);
+			if (rmsg->rm_direction != REPLY) {
+				return (FALSE);
+			}
+			rmsg->rm_reply.rp_stat =
+				IXDR_GET_ENUM(buf, enum reply_stat);
+			if (rmsg->rm_reply.rp_stat == MSG_ACCEPTED)
+				return (xdr_accepted_reply(xdrs,
+					&rmsg->acpted_rply));
+			else if (rmsg->rm_reply.rp_stat == MSG_DENIED)
+				return (xdr_rejected_reply(xdrs,
+					&rmsg->rjcted_rply));
+			else
+				return (FALSE);
+		}
+	}
+
 	prm_direction = &rmsg->rm_direction;
 	prp_stat = &rmsg->rm_reply.rp_stat;
 
@@ -220,7 +246,7 @@ xdr_callhdr(XDR *xdrs, struct rpc_msg *cmsg)
 
 /* ************************** Client utility routine ************* */
 
-static void
+static enum clnt_stat
 accepted(enum accept_stat acpt_stat, struct rpc_err *error)
 {
 
@@ -230,36 +256,32 @@ accepted(enum accept_stat acpt_stat, struct rpc_err *error)
 
 	case PROG_UNAVAIL:
 		error->re_status = RPC_PROGUNAVAIL;
-		return;
+		return (RPC_PROGUNAVAIL);
 
 	case PROG_MISMATCH:
 		error->re_status = RPC_PROGVERSMISMATCH;
-		return;
+		return (RPC_PROGVERSMISMATCH);
 
 	case PROC_UNAVAIL:
-		error->re_status = RPC_PROCUNAVAIL;
-		return;
+		return (RPC_PROCUNAVAIL);
 
 	case GARBAGE_ARGS:
-		error->re_status = RPC_CANTDECODEARGS;
-		return;
+		return (RPC_CANTDECODEARGS);
 
 	case SYSTEM_ERR:
-		error->re_status = RPC_SYSTEMERROR;
-		return;
+		return (RPC_SYSTEMERROR);
 
 	case SUCCESS:
-		error->re_status = RPC_SUCCESS;
-		return;
+		return (RPC_SUCCESS);
 	}
 	/* NOTREACHED */
 	/* something's wrong, but we don't know what ... */
-	error->re_status = RPC_FAILED;
 	error->re_lb.s1 = (int32_t)MSG_ACCEPTED;
 	error->re_lb.s2 = (int32_t)acpt_stat;
+	return (RPC_FAILED);
 }
 
-static void 
+static enum clnt_stat
 rejected(enum reject_stat rjct_stat, struct rpc_err *error)
 {
 
@@ -267,26 +289,25 @@ rejected(enum reject_stat rjct_stat, struct rpc_err *error)
 
 	switch (rjct_stat) {
 	case RPC_MISMATCH:
-		error->re_status = RPC_VERSMISMATCH;
-		return;
+		return (RPC_VERSMISMATCH);
 
 	case AUTH_ERROR:
-		error->re_status = RPC_AUTHERROR;
-		return;
+		return (RPC_AUTHERROR);
 	}
 	/* something's wrong, but we don't know what ... */
 	/* NOTREACHED */
-	error->re_status = RPC_FAILED;
 	error->re_lb.s1 = (int32_t)MSG_DENIED;
 	error->re_lb.s2 = (int32_t)rjct_stat;
+	return (RPC_FAILED);
 }
 
 /*
  * given a reply message, fills in the error
  */
-void
+enum clnt_stat
 _seterr_reply(struct rpc_msg *msg, struct rpc_err *error)
 {
+	enum clnt_stat stat;
 
 	assert(msg != NULL);
 	assert(error != NULL);
@@ -296,22 +317,24 @@ _seterr_reply(struct rpc_msg *msg, struct rpc_err *error)
 
 	case MSG_ACCEPTED:
 		if (msg->acpted_rply.ar_stat == SUCCESS) {
-			error->re_status = RPC_SUCCESS;
-			return;
+			stat = RPC_SUCCESS;
+			return (stat);
 		}
-		accepted(msg->acpted_rply.ar_stat, error);
+		stat = accepted(msg->acpted_rply.ar_stat, error);
 		break;
 
 	case MSG_DENIED:
-		rejected(msg->rjcted_rply.rj_stat, error);
+		stat = rejected(msg->rjcted_rply.rj_stat, error);
 		break;
 
 	default:
-		error->re_status = RPC_FAILED;
+		stat = RPC_FAILED;
 		error->re_lb.s1 = (int32_t)(msg->rm_reply.rp_stat);
 		break;
 	}
-	switch (error->re_status) {
+	error->re_status = stat;
+
+	switch (stat) {
 
 	case RPC_VERSMISMATCH:
 		error->re_vers.low = msg->rjcted_rply.rj_vers.low;
@@ -345,4 +368,6 @@ _seterr_reply(struct rpc_msg *msg, struct rpc_err *error)
 	default:
 		break;
 	}
+
+	return (stat);
 }