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

2 files changed, 108 insertions, 6 deletions

diff --git a/usr.sbin/mountd/exports.5 b/usr.sbin/mountd/exports.5
index f04b6b1..dca4f2d 100644
--- a/usr.sbin/mountd/exports.5
+++ b/usr.sbin/mountd/exports.5
@@ -149,6 +149,17 @@ option is given,
 all users (including root) will be mapped to that credential in
 place of their own.
 .Pp
+.Sm off
+.Fl sec Li = Sy flavor1:flavor2...
+.Sm on
+specifies a colon separated list of acceptable security flavors to be
+used for remote access.
+Supported security flavors are sys, krb5, krb5i and krb5p.
+If multiple flavors are listed, they should be ordered with the most
+preferred flavor first.
+If this option is not present,
+the default security flavor list of just sys is used.
+.Pp
 The
 .Fl ro
 option specifies that the file system should be exported read-only
@@ -305,6 +316,8 @@ the default remote mount-point file
 /u2 -maproot=root friends
 /u2 -alldirs -network cis-net -mask cis-mask
 /cdrom -alldirs,quiet,ro -network 192.168.33.0 -mask 255.255.255.0
+/private -sec=krb5i
+/secret -sec=krb5p
 .Ed
 .Pp
 Given that
@@ -411,6 +424,15 @@ While there is no CD-ROM medium mounted under
 it would export the (normally empty) directory
 .Pa /cdrom
 of the root file system instead.
+.Pp
+The file system rooted at
+.Pa /private
+will be exported using Kerberos 5 authentication and will require
+integrity protected messages for all accesses.
+The file system rooted at
+.Pa /secret
+will also be exported using Kerberos 5 authentication and all messages
+used to access it will be encrypted.
 .Sh SEE ALSO
 .Xr netgroup 5 ,
 .Xr mountd 8 ,
diff --git a/usr.sbin/mountd/mountd.c b/usr.sbin/mountd/mountd.c
index fbcb4ec..82ab1b8 100644
--- a/usr.sbin/mountd/mountd.c
+++ b/usr.sbin/mountd/mountd.c
@@ -113,6 +113,8 @@ struct exportlist {
 	fsid_t		ex_fs;
 	char		*ex_fsdir;
 	char		*ex_indexfile;
+	int		ex_numsecflavors;
+	int		ex_secflavors[MAXSECFLAVORS];
 };
 /* ex_flag bits */
 #define	EX_LINKED	0x1
@@ -150,6 +152,8 @@ struct fhreturn {
 	int	fhr_flag;
 	int	fhr_vers;
 	nfsfh_t	fhr_fh;
+	int	fhr_numsecflavors;
+	int	*fhr_secflavors;
 };
 
 /* Global defs */
@@ -240,6 +244,7 @@ struct pidfh *pfh = NULL;
 #define	OP_HAVEMASK	0x80	/* A mask was specified or inferred. */
 #define	OP_QUIET	0x100
 #define OP_MASKLEN	0x200
+#define OP_SEC		0x400
 
 #ifdef DEBUG
 int debug = 1;
@@ -817,6 +822,8 @@ mntsrv(rqstp, transp)
 				sigprocmask(SIG_UNBLOCK, &sighup_mask, NULL);
 				return;
 			}
+			fhr.fhr_numsecflavors = ep->ex_numsecflavors;
+			fhr.fhr_secflavors = ep->ex_secflavors;
 			if (!svc_sendreply(transp, (xdrproc_t)xdr_fhs,
 			    (caddr_t)&fhr))
 				syslog(LOG_ERR, "can't send reply");
@@ -934,6 +941,7 @@ xdr_fhs(xdrsp, cp)
 {
 	struct fhreturn *fhrp = (struct fhreturn *)cp;
 	u_long ok = 0, len, auth;
+	int i;
 
 	if (!xdr_long(xdrsp, &ok))
 		return (0);
@@ -946,11 +954,20 @@ xdr_fhs(xdrsp, cp)
 			return (0);
 		if (!xdr_opaque(xdrsp, (caddr_t)&fhrp->fhr_fh, len))
 			return (0);
-		auth = RPCAUTH_UNIX;
-		len = 1;
-		if (!xdr_long(xdrsp, &len))
-			return (0);
-		return (xdr_long(xdrsp, &auth));
+		if (fhrp->fhr_numsecflavors) {
+			if (!xdr_int(xdrsp, &fhrp->fhr_numsecflavors))
+				return (0);
+			for (i = 0; i < fhrp->fhr_numsecflavors; i++)
+				if (!xdr_int(xdrsp, &fhrp->fhr_secflavors[i]))
+					return (0);
+			return (1);
+		} else {
+			auth = AUTH_SYS;
+			len = 1;
+			if (!xdr_long(xdrsp, &len))
+				return (0);
+			return (xdr_long(xdrsp, &auth));
+		}
 	};
 	return (0);
 }
@@ -1765,6 +1782,57 @@ free_dir(dp)
 }
 
 /*
+ * Parse a colon separated list of security flavors
+ */
+int
+parsesec(seclist, ep)
+	char *seclist;
+	struct exportlist *ep;
+{
+	char *cp, savedc;
+	int flavor;
+
+	ep->ex_numsecflavors = 0;
+	for (;;) {
+		cp = strchr(seclist, ':');
+		if (cp) {
+			savedc = *cp;
+			*cp = '\0';
+		}
+
+		if (!strcmp(seclist, "sys"))
+			flavor = AUTH_SYS;
+		else if (!strcmp(seclist, "krb5"))
+			flavor = RPCSEC_GSS_KRB5;
+		else if (!strcmp(seclist, "krb5i"))
+			flavor = RPCSEC_GSS_KRB5I;
+		else if (!strcmp(seclist, "krb5p"))
+			flavor = RPCSEC_GSS_KRB5P;
+		else {
+			if (cp)
+				*cp = savedc;
+			syslog(LOG_ERR, "bad sec flavor: %s", seclist);
+			return (1);
+		}
+		if (ep->ex_numsecflavors == MAXSECFLAVORS) {
+			if (cp)
+				*cp = savedc;
+			syslog(LOG_ERR, "too many sec flavors: %s", seclist);
+			return (1);
+		}
+		ep->ex_secflavors[ep->ex_numsecflavors] = flavor;
+		ep->ex_numsecflavors++;
+		if (cp) {
+			*cp = savedc;
+			seclist = cp + 1;
+		} else {
+			break;
+		}
+	}
+	return (0);
+}
+
+/*
  * Parse the option string and update fields.
  * Option arguments may either be -<option>=<value> or
  * -<option> <value>
@@ -1859,6 +1927,11 @@ do_opt(cpp, endcpp, ep, grp, has_hostp, exflagsp, cr)
 			ep->ex_indexfile = strdup(cpoptarg);
 		} else if (!strcmp(cpopt, "quiet")) {
 			opt_flags |= OP_QUIET;
+		} else if (!strcmp(cpopt, "sec")) {
+			if (parsesec(cpoptarg, ep))
+				return (1);
+			opt_flags |= OP_SEC;
+			usedarg++;
 		} else {
 			syslog(LOG_ERR, "bad opt %s", cpopt);
 			return (1);
@@ -2018,7 +2091,7 @@ do_mount(struct exportlist *ep, struct grouplist *grp, int exflags,
 	int done;
 	char savedc;
 	struct iovec *iov;
-	int iovlen;
+	int i, iovlen;
 	int ret;
 
 	cp = NULL;
@@ -2036,6 +2109,13 @@ do_mount(struct exportlist *ep, struct grouplist *grp, int exflags,
 		ai = grp->gr_ptr.gt_addrinfo;
 	else
 		ai = NULL;
+	eap.ex_numsecflavors = ep->ex_numsecflavors;
+	for (i = 0; i < eap.ex_numsecflavors; i++)
+		eap.ex_secflavors[i] = ep->ex_secflavors[i];
+	if (eap.ex_numsecflavors == 0) {
+		eap.ex_numsecflavors = 1;
+		eap.ex_secflavors[0] = AUTH_SYS;
+	}
 	done = FALSE;
 
 	build_iovec(&iov, &iovlen, "fstype", NULL, 0);