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, 359 insertions, 0 deletions

diff --git a/sys/rpc/rpcsec_gss/rpcsec_gss_prot.c b/sys/rpc/rpcsec_gss/rpcsec_gss_prot.c
new file mode 100644
index 0000000..0654a6e
--- /dev/null
+++ b/sys/rpc/rpcsec_gss/rpcsec_gss_prot.c
@@ -0,0 +1,359 @@
+/*
+  rpcsec_gss_prot.c
+  
+  Copyright (c) 2000 The Regents of the University of Michigan.
+  All rights reserved.
+  
+  Copyright (c) 2000 Dug Song <dugsong@UMICH.EDU>.
+  All rights reserved, all wrongs reversed.
+  
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions
+  are met:
+
+  1. Redistributions of source code must retain the above copyright
+     notice, this list of conditions and the following disclaimer.
+  2. Redistributions in binary form must reproduce the above copyright
+     notice, this list of conditions and the following disclaimer in the
+     documentation and/or other materials provided with the distribution.
+  3. Neither the name of the University nor the names of its
+     contributors may be used to endorse or promote products derived
+     from this software without specific prior written permission.
+
+  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+  $Id: authgss_prot.c,v 1.18 2000/09/01 04:14:03 dugsong Exp $
+*/
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kobj.h>
+#include <sys/lock.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/mutex.h>
+
+#include <rpc/rpc.h>
+#include <rpc/rpcsec_gss.h>
+
+#include "rpcsec_gss_int.h"
+
+#define MAX_GSS_SIZE	10240	/* XXX */
+
+#if 0				/* use the one from kgssapi */
+bool_t
+xdr_gss_buffer_desc(XDR *xdrs, gss_buffer_desc *p)
+{
+	char *val;
+	u_int len;
+	bool_t ret;
+
+	val = p->value;
+	len = p->length;
+	ret = xdr_bytes(xdrs, &val, &len, MAX_GSS_SIZE);
+	p->value = val;
+	p->length = len;
+
+	return (ret);
+}
+#endif
+
+bool_t
+xdr_rpc_gss_cred(XDR *xdrs, struct rpc_gss_cred *p)
+{
+	enum_t proc, svc;
+	bool_t ret;
+
+	proc = p->gc_proc;
+	svc = p->gc_svc;
+	ret = (xdr_u_int(xdrs, &p->gc_version) &&
+	    xdr_enum(xdrs, &proc) &&
+	    xdr_u_int(xdrs, &p->gc_seq) &&
+	    xdr_enum(xdrs, &svc) &&
+	    xdr_gss_buffer_desc(xdrs, &p->gc_handle));
+	p->gc_proc = proc;
+	p->gc_svc = svc;
+
+	return (ret);
+}
+
+bool_t
+xdr_rpc_gss_init_res(XDR *xdrs, struct rpc_gss_init_res *p)
+{
+
+	return (xdr_gss_buffer_desc(xdrs, &p->gr_handle) &&
+	    xdr_u_int(xdrs, &p->gr_major) &&
+	    xdr_u_int(xdrs, &p->gr_minor) &&
+	    xdr_u_int(xdrs, &p->gr_win) &&
+	    xdr_gss_buffer_desc(xdrs, &p->gr_token));
+}
+
+static void
+put_uint32(struct mbuf **mp, uint32_t v)
+{
+	struct mbuf *m = *mp;
+	uint32_t n;
+
+	M_PREPEND(m, sizeof(uint32_t), M_WAIT);
+	n = htonl(v);
+	bcopy(&n, mtod(m, uint32_t *), sizeof(uint32_t));
+	*mp = m;
+}
+
+bool_t
+xdr_rpc_gss_wrap_data(struct mbuf **argsp,
+		      gss_ctx_id_t ctx, gss_qop_t qop,
+		      rpc_gss_service_t svc, u_int seq)
+{
+	struct mbuf	*args, *mic;
+	OM_uint32	maj_stat, min_stat;
+	int		conf_state;
+	u_int		len;
+	static char	zpad[4];
+
+	args = *argsp;
+
+	/*
+	 * Prepend the sequence number before calling gss_get_mic or gss_wrap.
+	 */
+	put_uint32(&args, seq);
+	len = m_length(args, NULL);
+
+	if (svc == rpc_gss_svc_integrity) {
+		/* Checksum rpc_gss_data_t. */
+		maj_stat = gss_get_mic_mbuf(&min_stat, ctx, qop, args, &mic);
+		if (maj_stat != GSS_S_COMPLETE) {
+			rpc_gss_log_debug("gss_get_mic failed");
+			m_freem(args);
+			return (FALSE);
+		}
+
+		/*
+		 * Marshal databody_integ. Note that since args is
+		 * already RPC encoded, there will be no padding.
+		 */
+		put_uint32(&args, len);
+
+		/*
+		 * Marshal checksum. This is likely to need padding.
+		 */
+		len = m_length(mic, NULL);
+		put_uint32(&mic, len);
+		if (len != RNDUP(len)) {
+			m_append(mic, RNDUP(len) - len, zpad);
+		}
+
+		/*
+		 * Concatenate databody_integ with checksum.
+		 */
+		m_cat(args, mic);
+	} else if (svc == rpc_gss_svc_privacy) {
+		/* Encrypt rpc_gss_data_t. */
+		maj_stat = gss_wrap_mbuf(&min_stat, ctx, TRUE, qop,
+		    &args, &conf_state);
+		if (maj_stat != GSS_S_COMPLETE) {
+			rpc_gss_log_status("gss_wrap", NULL,
+			    maj_stat, min_stat);
+			return (FALSE);
+		}
+
+		/*
+		 *  Marshal databody_priv and deal with RPC padding.
+		 */
+		len = m_length(args, NULL);
+		put_uint32(&args, len);
+		if (len != RNDUP(len)) {
+			m_append(args, RNDUP(len) - len, zpad);
+		}
+	}
+	*argsp = args;
+	return (TRUE);
+}
+
+static uint32_t
+get_uint32(struct mbuf **mp)
+{
+	struct mbuf *m = *mp;
+	uint32_t n;
+
+	if (m->m_len < sizeof(uint32_t)) {
+		m = m_pullup(m, sizeof(uint32_t));
+		if (!m) {
+			*mp = NULL;
+			return (0);
+		}
+	}
+	bcopy(mtod(m, uint32_t *), &n, sizeof(uint32_t));
+	m_adj(m, sizeof(uint32_t));
+	*mp = m;
+	return (ntohl(n));
+}
+
+static void
+m_trim(struct mbuf *m, int len)
+{
+	struct mbuf *n;
+	int off;
+
+	n = m_getptr(m, len, &off);
+	if (n) {
+		n->m_len = off;
+		if (n->m_next) {
+			m_freem(n->m_next);
+			n->m_next = NULL;
+		}
+	}
+}
+
+bool_t
+xdr_rpc_gss_unwrap_data(struct mbuf **resultsp,
+			gss_ctx_id_t ctx, gss_qop_t qop,
+			rpc_gss_service_t svc, u_int seq)
+{
+	struct mbuf	*results, *message, *mic;
+	uint32_t	len, cklen;
+	OM_uint32	maj_stat, min_stat;
+	u_int		seq_num, conf_state, qop_state;
+
+	results = *resultsp;
+	*resultsp = NULL;
+	
+	message = NULL;
+	if (svc == rpc_gss_svc_integrity) {
+		/*
+		 * Extract the seq+message part. Remember that there
+		 * may be extra RPC padding in the checksum. The
+		 * message part is RPC encoded already so no
+		 * padding.
+		 */
+		len = get_uint32(&results);
+		message = results;
+		results = m_split(results, len, M_WAIT);
+		if (!results) {
+			m_freem(message);
+			return (FALSE);
+		}
+
+		/*
+		 * Extract the MIC and make it contiguous.
+		 */
+		cklen = get_uint32(&results);
+		KASSERT(cklen <= MHLEN, ("unexpected large GSS-API checksum"));
+		mic = results;
+		if (cklen > mic->m_len)
+			mic = m_pullup(mic, cklen);
+		if (cklen != RNDUP(cklen))
+			m_trim(mic, cklen);
+
+		/* Verify checksum and QOP. */
+		maj_stat = gss_verify_mic_mbuf(&min_stat, ctx,
+		    message, mic, &qop_state);
+		m_freem(mic);
+		
+		if (maj_stat != GSS_S_COMPLETE || qop_state != qop) {
+			m_freem(message);
+			rpc_gss_log_status("gss_verify_mic", NULL,
+			    maj_stat, min_stat);
+			return (FALSE);
+		}
+	} else if (svc == rpc_gss_svc_privacy) {
+		/* Decode databody_priv. */
+		len = get_uint32(&results);
+
+		/* Decrypt databody. */
+		message = results;
+		if (len != RNDUP(len))
+			m_trim(message, len);
+		maj_stat = gss_unwrap_mbuf(&min_stat, ctx, &message,
+		    &conf_state, &qop_state);
+		
+		/* Verify encryption and QOP. */
+		if (maj_stat != GSS_S_COMPLETE) {
+			rpc_gss_log_status("gss_unwrap", NULL,
+			    maj_stat, min_stat);
+			return (FALSE);
+		}
+		if (qop_state != qop || conf_state != TRUE) {
+			m_freem(results);
+			return (FALSE);
+		}
+	}
+
+	/* Decode rpc_gss_data_t (sequence number + arguments). */
+	seq_num = get_uint32(&message);
+	
+	/* Verify sequence number. */
+	if (seq_num != seq) {
+		rpc_gss_log_debug("wrong sequence number in databody");
+		m_freem(message);
+		return (FALSE);
+	}
+
+	*resultsp = message;
+	return (TRUE);
+}
+
+#ifdef DEBUG
+#include <ctype.h>
+
+void
+rpc_gss_log_debug(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fprintf(stderr, "rpcsec_gss: ");
+	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, "\n");
+	va_end(ap);
+}
+
+void
+rpc_gss_log_status(const char *m, gss_OID mech, OM_uint32 maj_stat, OM_uint32 min_stat)
+{
+	OM_uint32 min;
+	gss_buffer_desc msg;
+	int msg_ctx = 0;
+
+	fprintf(stderr, "rpcsec_gss: %s: ", m);
+	
+	gss_display_status(&min, maj_stat, GSS_C_GSS_CODE, GSS_C_NULL_OID,
+			   &msg_ctx, &msg);
+	printf("%s - ", (char *)msg.value);
+	gss_release_buffer(&min, &msg);
+
+	gss_display_status(&min, min_stat, GSS_C_MECH_CODE, mech,
+			   &msg_ctx, &msg);
+	printf("%s\n", (char *)msg.value);
+	gss_release_buffer(&min, &msg);
+}
+
+#else
+
+void
+rpc_gss_log_debug(__unused const char *fmt, ...)
+{
+}
+
+void
+rpc_gss_log_status(__unused const char *m, __unused gss_OID mech,
+    __unused OM_uint32 maj_stat, __unused OM_uint32 min_stat)
+{
+}
+
+#endif
+
+