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, 565 insertions, 0 deletions

diff --git a/sys/nfsserver/nfs_srvkrpc.c b/sys/nfsserver/nfs_srvkrpc.c
new file mode 100644
index 0000000..509dc58
--- /dev/null
+++ b/sys/nfsserver/nfs_srvkrpc.c
@@ -0,0 +1,565 @@
+/*-
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Rick Macklem at The University of Guelph.
+ *
+ * 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.
+ * 4. 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 BY THE REGENTS AND CONTRIBUTORS ``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.
+ *
+ *	@(#)nfs_syscalls.c	8.5 (Berkeley) 3/30/95
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "opt_inet6.h"
+#include "opt_kgssapi.h"
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/sysproto.h>
+#include <sys/kernel.h>
+#include <sys/sysctl.h>
+#include <sys/file.h>
+#include <sys/filedesc.h>
+#include <sys/vnode.h>
+#include <sys/malloc.h>
+#include <sys/mount.h>
+#include <sys/priv.h>
+#include <sys/proc.h>
+#include <sys/bio.h>
+#include <sys/buf.h>
+#include <sys/mbuf.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+#include <sys/domain.h>
+#include <sys/protosw.h>
+#include <sys/namei.h>
+#include <sys/fcntl.h>
+#include <sys/lockf.h>
+
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#ifdef INET6
+#include <net/if.h>
+#include <netinet6/in6_var.h>
+#endif
+
+#include <rpc/rpc.h>
+#include <rpc/rpcsec_gss.h>
+#include <rpc/replay.h>
+
+#include <nfs/xdr_subs.h>
+#include <nfs/rpcv2.h>
+#include <nfs/nfsproto.h>
+#include <nfsserver/nfs.h>
+#include <nfsserver/nfsm_subs.h>
+#include <nfsserver/nfsrvcache.h>
+#include <nfsserver/nfs_fha.h>
+
+#ifndef NFS_LEGACYRPC
+
+static MALLOC_DEFINE(M_NFSSVC, "nfss_srvsock", "Nfs server structure");
+
+MALLOC_DEFINE(M_NFSRVDESC, "nfss_srvdesc", "NFS server socket descriptor");
+MALLOC_DEFINE(M_NFSD, "nfss_daemon", "Nfs server daemon structure");
+
+#define	TRUE	1
+#define	FALSE	0
+
+SYSCTL_DECL(_vfs_nfsrv);
+
+SVCPOOL		*nfsrv_pool;
+int		nfsd_waiting = 0;
+int		nfsrv_numnfsd = 0;
+static int	nfs_realign_test;
+static int	nfs_realign_count;
+struct callout	nfsrv_callout;
+static eventhandler_tag nfsrv_nmbclusters_tag;
+
+static int	nfs_privport = 0;
+SYSCTL_INT(_vfs_nfsrv, NFS_NFSPRIVPORT, nfs_privport, CTLFLAG_RW,
+    &nfs_privport, 0,
+    "Only allow clients using a privileged port");
+SYSCTL_INT(_vfs_nfsrv, OID_AUTO, gatherdelay, CTLFLAG_RW,
+    &nfsrvw_procrastinate, 0,
+    "Delay value for write gathering");
+SYSCTL_INT(_vfs_nfsrv, OID_AUTO, gatherdelay_v3, CTLFLAG_RW,
+    &nfsrvw_procrastinate_v3, 0,
+    "Delay in seconds for NFSv3 write gathering");
+SYSCTL_INT(_vfs_nfsrv, OID_AUTO, realign_test, CTLFLAG_RW,
+	    &nfs_realign_test, 0, "");
+SYSCTL_INT(_vfs_nfsrv, OID_AUTO, realign_count, CTLFLAG_RW,
+	    &nfs_realign_count, 0, "");
+
+static int	nfssvc_addsock(struct file *, struct thread *);
+static int	nfssvc_nfsd(struct thread *, struct nfsd_nfsd_args *);
+
+extern u_long sb_max_adj;
+
+int32_t (*nfsrv3_procs[NFS_NPROCS])(struct nfsrv_descript *nd,
+    struct nfssvc_sock *slp, struct mbuf **mreqp) = {
+	nfsrv_null,
+	nfsrv_getattr,
+	nfsrv_setattr,
+	nfsrv_lookup,
+	nfsrv3_access,
+	nfsrv_readlink,
+	nfsrv_read,
+	nfsrv_write,
+	nfsrv_create,
+	nfsrv_mkdir,
+	nfsrv_symlink,
+	nfsrv_mknod,
+	nfsrv_remove,
+	nfsrv_rmdir,
+	nfsrv_rename,
+	nfsrv_link,
+	nfsrv_readdir,
+	nfsrv_readdirplus,
+	nfsrv_statfs,
+	nfsrv_fsinfo,
+	nfsrv_pathconf,
+	nfsrv_commit,
+	nfsrv_noop
+};
+
+/*
+ * NFS server system calls
+ */
+
+/*
+ * Nfs server psuedo system call for the nfsd's
+ * Based on the flag value it either:
+ * - adds a socket to the selection list
+ * - remains in the kernel as an nfsd
+ * - remains in the kernel as an nfsiod
+ * For INET6 we suppose that nfsd provides only IN6P_IPV6_V6ONLY sockets
+ * and that mountd provides
+ *  - sockaddr with no IPv4-mapped addresses
+ *  - mask for both INET and INET6 families if there is IPv4-mapped overlap
+ */
+#ifndef _SYS_SYSPROTO_H_
+struct nfssvc_args {
+	int flag;
+	caddr_t argp;
+};
+#endif
+int
+nfssvc(struct thread *td, struct nfssvc_args *uap)
+{
+	struct file *fp;
+	struct nfsd_addsock_args addsockarg;
+	struct nfsd_nfsd_args nfsdarg;
+	int error;
+
+	KASSERT(!mtx_owned(&Giant), ("nfssvc(): called with Giant"));
+
+	error = priv_check(td, PRIV_NFS_DAEMON);
+	if (error)
+		return (error);
+	if (uap->flag & NFSSVC_ADDSOCK) {
+		error = copyin(uap->argp, (caddr_t)&addsockarg,
+		    sizeof(addsockarg));
+		if (error)
+			return (error);
+		if ((error = fget(td, addsockarg.sock, &fp)) != 0)
+			return (error);
+		if (fp->f_type != DTYPE_SOCKET) {
+			fdrop(fp, td);
+			return (error);	/* XXXRW: Should be EINVAL? */
+		}
+		error = nfssvc_addsock(fp, td);
+		fdrop(fp, td);
+	} else if (uap->flag & NFSSVC_OLDNFSD) {
+		error = nfssvc_nfsd(td, NULL);
+	} else if (uap->flag & NFSSVC_NFSD) {
+		if (!uap->argp) 
+			return (EINVAL);
+		error = copyin(uap->argp, (caddr_t)&nfsdarg,
+		    sizeof(nfsdarg));
+		if (error)
+			return (error);
+		error = nfssvc_nfsd(td, &nfsdarg);
+	} else {
+		error = ENXIO;
+	}
+	if (error == EINTR || error == ERESTART)
+		error = 0;
+	return (error);
+}
+
+/*
+ * Generate the rpc reply header
+ * siz arg. is used to decide if adding a cluster is worthwhile
+ */
+struct mbuf *
+nfs_rephead(int siz, struct nfsrv_descript *nd, int err,
+    struct mbuf **mbp, caddr_t *bposp)
+{
+	u_int32_t *tl;
+	struct mbuf *mreq;
+	caddr_t bpos;
+	struct mbuf *mb;
+
+	if (err == EBADRPC)
+		return (NULL);
+
+	nd->nd_repstat = err;
+	if (err && (nd->nd_flag & ND_NFSV3) == 0)	/* XXX recheck */
+		siz = 0;
+
+	MGET(mreq, M_WAIT, MT_DATA);
+
+	/*
+	 * If this is a big reply, use a cluster
+	 */
+	mreq->m_len = 0;
+	if (siz >= MINCLSIZE) {
+		MCLGET(mreq, M_WAIT);
+	}
+	mb = mreq;
+	bpos = mtod(mb, caddr_t);
+
+	if (err != NFSERR_RETVOID) {
+		tl = nfsm_build(u_int32_t *, NFSX_UNSIGNED);
+		if (err)
+			*tl = txdr_unsigned(nfsrv_errmap(nd, err));
+		else
+			*tl = 0;
+	}
+
+	*mbp = mb;
+	*bposp = bpos;
+	if (err != 0 && err != NFSERR_RETVOID)
+		nfsrvstats.srvrpc_errs++;
+
+	return (mreq);
+}
+
+/*
+ *	nfs_realign:
+ *
+ *	Check for badly aligned mbuf data and realign by copying the unaligned
+ *	portion of the data into a new mbuf chain and freeing the portions
+ *	of the old chain that were replaced.
+ *
+ *	We cannot simply realign the data within the existing mbuf chain
+ *	because the underlying buffers may contain other rpc commands and
+ *	we cannot afford to overwrite them.
+ *
+ *	We would prefer to avoid this situation entirely.  The situation does
+ *	not occur with NFS/UDP and is supposed to only occassionally occur
+ *	with TCP.  Use vfs.nfs.realign_count and realign_test to check this.
+ */
+static void
+nfs_realign(struct mbuf **pm)	/* XXX COMMON */
+{
+	struct mbuf *m;
+	struct mbuf *n = NULL;
+	int off = 0;
+
+	++nfs_realign_test;
+	while ((m = *pm) != NULL) {
+		if ((m->m_len & 0x3) || (mtod(m, intptr_t) & 0x3)) {
+			MGET(n, M_WAIT, MT_DATA);
+			if (m->m_len >= MINCLSIZE) {
+				MCLGET(n, M_WAIT);
+			}
+			n->m_len = 0;
+			break;
+		}
+		pm = &m->m_next;
+	}
+
+	/*
+	 * If n is non-NULL, loop on m copying data, then replace the
+	 * portion of the chain that had to be realigned.
+	 */
+	if (n != NULL) {
+		++nfs_realign_count;
+		while (m) {
+			m_copyback(n, off, m->m_len, mtod(m, caddr_t));
+			off += m->m_len;
+			m = m->m_next;
+		}
+		m_freem(*pm);
+		*pm = n;
+	}
+}
+
+static void
+nfssvc_program(struct svc_req *rqst, SVCXPRT *xprt)
+{
+	rpcproc_t procnum;
+	int32_t (*proc)(struct nfsrv_descript *nd, struct nfssvc_sock *slp,
+	    struct mbuf **mreqp);
+	int flag;
+	struct nfsrv_descript nd;
+	struct mbuf *mreq, *mrep;
+	int error;
+
+	if (rqst->rq_vers == NFS_VER2) {
+		if (rqst->rq_proc > NFSV2PROC_STATFS) {
+			svcerr_noproc(rqst);
+			svc_freereq(rqst);
+			return;
+		}
+		procnum = nfsrv_nfsv3_procid[rqst->rq_proc];
+		flag = 0;
+	} else {
+		if (rqst->rq_proc >= NFS_NPROCS) {
+			svcerr_noproc(rqst);
+			svc_freereq(rqst);
+			return;
+		}
+		procnum = rqst->rq_proc;
+		flag = ND_NFSV3;
+	}
+	proc = nfsrv3_procs[procnum];
+
+	mreq = mrep = NULL;
+	mreq = rqst->rq_args;
+	rqst->rq_args = NULL;
+	nfs_realign(&mreq);
+
+	/*
+	 * Note: we want rq_addr, not svc_getrpccaller -
+	 * NFS_SRVMAXDATA uses a NULL value for nd_nam2 to detect TCP
+	 * mounts.
+	 */
+	memset(&nd, 0, sizeof(nd));
+	nd.nd_md = nd.nd_mrep = mreq;
+	nd.nd_dpos = mtod(mreq, caddr_t);
+	nd.nd_nam = (struct sockaddr *) &xprt->xp_ltaddr;
+	nd.nd_nam2 = rqst->rq_addr;
+	nd.nd_procnum = procnum;
+	nd.nd_cr = NULL;
+	nd.nd_flag = flag;
+
+	if (proc != nfsrv_null) {
+		if (!svc_getcred(rqst, &nd.nd_cr, &nd.nd_credflavor)) {
+			svcerr_weakauth(rqst);
+			svc_freereq(rqst);
+			return;
+		}
+#ifdef MAC
+		mac_cred_associate_nfsd(nd.nd_cr);
+#endif
+	}
+	nfsrvstats.srvrpccnt[nd.nd_procnum]++;
+
+	error = proc(&nd, NULL, &mrep);
+
+	if (nd.nd_cr)
+		crfree(nd.nd_cr);
+
+	if (mrep == NULL) {
+		svcerr_decode(rqst);
+		svc_freereq(rqst);
+		return;
+	}
+	if (error && error != NFSERR_RETVOID) {
+		svcerr_systemerr(rqst);
+		svc_freereq(rqst);
+		return;
+	}
+	if (!svc_sendreply_mbuf(rqst, mrep))
+		svcerr_systemerr(rqst);
+	svc_freereq(rqst);
+}
+
+/*
+ * Adds a socket to the list for servicing by nfsds.
+ */
+static int
+nfssvc_addsock(struct file *fp, struct thread *td)
+{
+	int siz;
+	struct socket *so;
+	int error;
+	SVCXPRT *xprt;
+
+	so = fp->f_data;
+
+	siz = sb_max_adj;
+	error = soreserve(so, siz, siz);
+	if (error) {
+		return (error);
+	}
+
+	/*
+	 * Steal the socket from userland so that it doesn't close
+	 * unexpectedly.
+	 */
+	if (so->so_type == SOCK_DGRAM)
+		xprt = svc_dg_create(nfsrv_pool, so, 0, 0);
+	else
+		xprt = svc_vc_create(nfsrv_pool, so, 0, 0);
+	if (xprt) {
+		fp->f_ops = &badfileops;
+		fp->f_data = NULL;
+		svc_reg(xprt, NFS_PROG, NFS_VER2, nfssvc_program, NULL);
+		svc_reg(xprt, NFS_PROG, NFS_VER3, nfssvc_program, NULL);
+	}
+
+	return (0);
+}
+
+/*
+ * Called by nfssvc() for nfsds. Just loops around servicing rpc requests
+ * until it is killed by a signal.
+ */
+static int
+nfssvc_nfsd(struct thread *td, struct nfsd_nfsd_args *args)
+{
+#ifdef KGSSAPI
+	char principal[128];
+	int error;
+#endif
+
+#ifdef KGSSAPI
+	if (args) {
+		error = copyinstr(args->principal, principal,
+		    sizeof(principal), NULL);
+		if (error)
+			return (error);
+	} else {
+		snprintf(principal, sizeof(principal), "nfs@%s", hostname);
+	}
+#endif
+
+	/*
+	 * Only the first nfsd actually does any work. The RPC code
+	 * adds threads to it as needed. Any extra processes offered
+	 * by nfsd just exit. If nfsd is new enough, it will call us
+	 * once with a structure that specifies how many threads to
+	 * use.
+	 */
+	NFSD_LOCK();
+	if (nfsrv_numnfsd == 0) {
+		nfsrv_numnfsd++;
+
+		NFSD_UNLOCK();
+
+#ifdef KGSSAPI
+		rpc_gss_set_svc_name(principal, "kerberosv5",
+		    GSS_C_INDEFINITE, NFS_PROG, NFS_VER2);
+		rpc_gss_set_svc_name(principal, "kerberosv5",
+		    GSS_C_INDEFINITE, NFS_PROG, NFS_VER3);
+#endif
+
+		if (args) {
+			nfsrv_pool->sp_minthreads = args->minthreads;
+			nfsrv_pool->sp_maxthreads = args->maxthreads;
+		} else {
+			nfsrv_pool->sp_minthreads = 4;
+			nfsrv_pool->sp_maxthreads = 4;
+		}
+			
+		svc_run(nfsrv_pool);
+
+#ifdef KGSSAPI
+		rpc_gss_clear_svc_name(NFS_PROG, NFS_VER2);
+		rpc_gss_clear_svc_name(NFS_PROG, NFS_VER3);
+#endif
+
+		NFSD_LOCK();
+		nfsrv_numnfsd--;
+		nfsrv_init(TRUE);
+	}
+	NFSD_UNLOCK();
+
+	return (0);
+}
+
+/*
+ * Size the NFS server's duplicate request cache at 1/2 the
+ * nmbclusters, floating within a (64, 2048) range. This is to
+ * prevent all mbuf clusters being tied up in the NFS dupreq
+ * cache for small values of nmbclusters.
+ */
+static size_t
+nfsrv_replay_size(void)
+{
+	size_t replaysiz;
+
+	replaysiz = nmbclusters / 2;
+	if (replaysiz > NFSRVCACHE_MAX_SIZE)
+		replaysiz = NFSRVCACHE_MAX_SIZE;
+	if (replaysiz < NFSRVCACHE_MIN_SIZE)
+		replaysiz = NFSRVCACHE_MIN_SIZE;
+	replaysiz *= MCLBYTES;
+
+	return (replaysiz);
+}
+
+/*
+ * Called when nmbclusters changes - we resize the replay cache
+ * accordingly.
+ */
+static void
+nfsrv_nmbclusters_change(void *tag)
+{
+
+	if (nfsrv_pool)
+		replay_setsize(nfsrv_pool->sp_rcache, nfsrv_replay_size());
+}
+
+/*
+ * Initialize the data structures for the server.
+ * Handshake with any new nfsds starting up to avoid any chance of
+ * corruption.
+ */
+void
+nfsrv_init(int terminating)
+{
+
+	NFSD_LOCK_ASSERT();
+
+	if (terminating) {
+		NFSD_UNLOCK();
+		EVENTHANDLER_DEREGISTER(nmbclusters_change,
+		    nfsrv_nmbclusters_tag);
+		svcpool_destroy(nfsrv_pool);
+		nfsrv_pool = NULL;
+		NFSD_LOCK();
+	} else
+		nfs_pub.np_valid = 0;
+
+	NFSD_UNLOCK();
+
+	nfsrv_pool = svcpool_create("nfsd", SYSCTL_STATIC_CHILDREN(_vfs_nfsrv));
+	nfsrv_pool->sp_rcache = replay_newcache(nfsrv_replay_size());
+	nfsrv_pool->sp_assign = fha_assign;
+	nfsrv_pool->sp_done = fha_nd_complete;
+	nfsrv_nmbclusters_tag = EVENTHANDLER_REGISTER(nmbclusters_change,
+	    nfsrv_nmbclusters_change, NULL, EVENTHANDLER_PRI_FIRST);
+
+	NFSD_LOCK();
+}
+
+#endif /* !NFS_LEGACYRPC */