Give nfsd the ability to bind to specific IP addresses through the -h

    option and add explicit option to bind to the wildcard address.  The
    default is to bind to the wildcard address when no -h option has been
    specified and thus backwards compatibility is maintained.

PR:		kern/13049
Reviewed by:	David Malone <dwmalone@maths.tcd.ie>
Submitted by:	Matt Dillon <dillon@freebsd.org>, David Malone <dwmalone@maths.tcd.ie>

2 files changed, 93 insertions, 25 deletions

diff --git a/sbin/nfsd/nfsd.8 b/sbin/nfsd/nfsd.8
index e3d3e1c..f0314ae 100644
--- a/sbin/nfsd/nfsd.8
+++ b/sbin/nfsd/nfsd.8
@@ -42,8 +42,9 @@
 server
 .Sh SYNOPSIS
 .Nm nfsd
-.Op Fl rut
+.Op Fl arut
 .Op Fl n Ar num_servers
+.Op Fl h Ar bindip
 .Sh DESCRIPTION
 .Nm Nfsd
 runs on a server machine to service
@@ -72,6 +73,19 @@ or
 options to re-register NFS if the portmap server is restarted.
 .It Fl n
 Specifies how many servers to create.
+.It Fl h Ar bindip
+Specifies which IP address or hostname to bind to on the local host.
+This option is recommended when a host has multiple interfaces. Multiple
+.Fl h
+options may be specified.
+.It Fl a
+Specifies that nfsd should bind to the wildcard IP address.
+This is the default if no
+.Fl h
+options are given.  It may also be specified in addition to any
+.Fl h
+options given.  Note that NFS/UDP does not operate properly when
+bound to the wildcard IP address whether you use -a or do not use -h.
 .It Fl t
 Serve
 .Tn TCP NFS
@@ -119,6 +133,19 @@ KLD is available,
 .Nm nfsd
 will exit with an error.
 .Pp
+If
+.Nm nfsd
+is to be run on a host with multiple interfaces or interface aliases, use
+of the
+.Fl h
+option is recommended.  If you do not use the option NFS may not respond to
+UDP packets from the same IP address they were sent to.  Use of this option
+is also recommended when securing NFS exports on a firewalling machine such
+that the NFS sockets can only be accessed by the inside interface.
+.Nm Ipfw
+would then be used to block nfs-related packets that come in on the outside
+interface.
+.Pp
 The
 .Nm nfsd
 utility exits 0 on success, and >0 if an error occurs.
@@ -127,7 +154,8 @@ utility exits 0 on success, and >0 if an error occurs.
 .Xr nfssvc 2 ,
 .Xr kldload 8 ,
 .Xr mountd 8 ,
-.Xr portmap 8
+.Xr portmap 8 ,
+.Xr ipfw 8
 .Sh HISTORY
 The
 .Nm nfsd
diff --git a/sbin/nfsd/nfsd.c b/sbin/nfsd/nfsd.c
index ca7ecef..9ff9d98 100644
--- a/sbin/nfsd/nfsd.c
+++ b/sbin/nfsd/nfsd.c
@@ -56,6 +56,8 @@ static const char rcsid[] =
 #include <rpc/rpc.h>
 #include <rpc/pmap_clnt.h>
 
+#include <netdb.h>
+#include <arpa/inet.h>
 #ifdef ISO
 #include <netiso/iso.h>
 #endif
@@ -104,6 +106,7 @@ NFSKERBKEYSCHED_T kerb_keysched;
 
 void	nonfs __P((int));
 void	reapchild __P((int));
+void	setbindhost __P((struct sockaddr_in *ia, const char *bindhost));
 #ifdef OLD_SETPROCTITLE
 #ifdef __FreeBSD__
 void	setproctitle __P((char *));
@@ -145,6 +148,8 @@ main(argc, argv, envp)
 	int ch, cltpflag, connect_type_cnt, i, len, maxsock, msgsock;
 	int nfsdcnt, nfssvc_flag, on, reregister, sock, tcpflag, tcpsock;
 	int tp4cnt, tp4flag, tpipcnt, tpipflag, udpflag;
+	int bindhostc = 0, bindanyflag;
+	char **bindhost = NULL;
 #ifdef notyet
 	int tp4sock, tpipsock;
 #endif
@@ -184,16 +189,19 @@ main(argc, argv, envp)
 #define	DEFNFSDCNT	 4
 	nfsdcnt = DEFNFSDCNT;
 	cltpflag = reregister = tcpflag = tp4cnt = tp4flag = tpipcnt = 0;
-	tpipflag = udpflag = 0;
+	bindanyflag = tpipflag = udpflag = 0;
 #ifdef ISO
-#define	GETOPT	"cn:rtu"
-#define	USAGE	"[-crtu] [-n num_servers]"
+#define	GETOPT	"ach:n:rtu"
+#define	USAGE	"[-acrtu] [-n num_servers] [-h bindip]"
 #else
-#define	GETOPT	"n:rtu"
-#define	USAGE	"[-rtu] [-n num_servers]"
+#define	GETOPT	"ah:n:rtu"
+#define	USAGE	"[-artu] [-n num_servers] [-h bindip]"
 #endif
 	while ((ch = getopt(argc, argv, GETOPT)) != -1)
 		switch (ch) {
+		case 'a':
+			bindanyflag = 1;
+			break;
 		case 'n':
 			nfsdcnt = atoi(optarg);
 			if (nfsdcnt < 1 || nfsdcnt > MAXNFSDCNT) {
@@ -202,6 +210,15 @@ main(argc, argv, envp)
 				nfsdcnt = DEFNFSDCNT;
 			}
 			break;
+		case 'h':
+			bindhostc++;
+			bindhost = realloc(bindhost,sizeof(char *)*bindhostc);
+			if (bindhost == NULL) 
+				errx(1, "Out of memory");
+			bindhost[bindhostc-1] = strdup(optarg);
+			if (bindhost[bindhostc-1] == NULL)
+				errx(1, "Out of memory");
+			break;
 		case 'r':
 			reregister = 1;
 			break;
@@ -248,6 +265,16 @@ main(argc, argv, envp)
 		}
 	}
 
+	if (bindhostc == 0 || bindanyflag) {
+		bindhostc++;
+		bindhost = realloc(bindhost,sizeof(char *)*bindhostc);
+		if (bindhost == NULL) 
+			errx(1, "Out of memory");
+		bindhost[bindhostc-1] = strdup("*");
+		if (bindhost[bindhostc-1] == NULL) 
+			errx(1, "Out of memory");
+	}
+
 	if (debug == 0) {
 		daemon(0, 0);
 		(void)signal(SIGHUP, SIG_IGN);
@@ -374,18 +401,15 @@ main(argc, argv, envp)
 	}
 
 	/* If we are serving udp, set up the socket. */
-	if (udpflag) {
+	for (i = 0; udpflag && i < bindhostc; i++) {
 		if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
 			syslog(LOG_ERR, "can't create udp socket");
 			exit(1);
 		}
-		inetaddr.sin_family = AF_INET;
-		inetaddr.sin_addr.s_addr = INADDR_ANY;
-		inetaddr.sin_port = htons(NFS_PORT);
-		inetaddr.sin_len = sizeof(inetaddr);
+		setbindhost(&inetaddr, bindhost[i]);
 		if (bind(sock,
 		    (struct sockaddr *)&inetaddr, sizeof(inetaddr)) < 0) {
-			syslog(LOG_ERR, "can't bind udp addr");
+			syslog(LOG_ERR, "can't bind udp addr %s: %m", bindhost[i]);
 			exit(1);
 		}
 		if (!pmap_set(RPCPROG_NFS, 2, IPPROTO_UDP, NFS_PORT) ||
@@ -448,7 +472,7 @@ main(argc, argv, envp)
 	on = 1;
 	FD_ZERO(&sockbits);
 	connect_type_cnt = 0;
-	if (tcpflag) {
+	for (i = 0; tcpflag && i < bindhostc; i++) {
 		if ((tcpsock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
 			syslog(LOG_ERR, "can't create tcp socket");
 			exit(1);
@@ -456,13 +480,10 @@ main(argc, argv, envp)
 		if (setsockopt(tcpsock,
 		    SOL_SOCKET, SO_REUSEADDR, (char *)&on, sizeof(on)) < 0)
 			syslog(LOG_ERR, "setsockopt SO_REUSEADDR: %m");
-		inetaddr.sin_family = AF_INET;
-		inetaddr.sin_addr.s_addr = INADDR_ANY;
-		inetaddr.sin_port = htons(NFS_PORT);
-		inetaddr.sin_len = sizeof(inetaddr);
+		setbindhost(&inetaddr, bindhost[i]);
 		if (bind(tcpsock,
 		    (struct sockaddr *)&inetaddr, sizeof (inetaddr)) < 0) {
-			syslog(LOG_ERR, "can't bind tcp addr");
+			syslog(LOG_ERR, "can't bind tcp addr %s: %m", bindhost[i]);
 			exit(1);
 		}
 		if (listen(tcpsock, 5) < 0) {
@@ -520,7 +541,7 @@ main(argc, argv, envp)
 	}
 
 	/* Now set up the master server socket waiting for tpip connections. */
-	if (tpipflag) {
+	for (i = 0; tpipflag && i < bindhostc; i++) {
 		if ((tpipsock = socket(AF_INET, SOCK_SEQPACKET, 0)) < 0) {
 			syslog(LOG_ERR, "can't create tpip socket");
 			exit(1);
@@ -528,13 +549,10 @@ main(argc, argv, envp)
 		if (setsockopt(tpipsock,
 		    SOL_SOCKET, SO_REUSEADDR, (char *)&on, sizeof(on)) < 0)
 			syslog(LOG_ERR, "setsockopt SO_REUSEADDR: %m");
-		inetaddr.sin_family = AF_INET;
-		inetaddr.sin_addr.s_addr = INADDR_ANY;
-		inetaddr.sin_port = htons(NFS_PORT);
-		inetaddr.sin_len = sizeof(inetaddr);
+		setbindhost(&inetaddr, bindhost[i]);
 		if (bind(tpipsock,
 		    (struct sockaddr *)&inetaddr, sizeof (inetaddr)) < 0) {
-			syslog(LOG_ERR, "can't bind tcp addr");
+			syslog(LOG_ERR, "can't bind tcp addr %s: %m", bindhost[i]);
 			exit(1);
 		}
 		if (listen(tpipsock, 5) < 0) {
@@ -631,6 +649,28 @@ main(argc, argv, envp)
 }
 
 void
+setbindhost(struct sockaddr_in *ia, const char *bindhost)
+{
+	ia->sin_family = AF_INET;
+	ia->sin_port = htons(NFS_PORT);
+	ia->sin_len = sizeof(*ia);
+	if (bindhost == NULL || strcmp(bindhost,"*") == 0) {
+		ia->sin_addr.s_addr = INADDR_ANY;
+	} else {
+		if (inet_aton(bindhost, &ia->sin_addr) == 0) {
+			struct hostent *he;
+
+			he = gethostbyname2(bindhost, ia->sin_family);
+			if (he == NULL) {
+				syslog(LOG_ERR, "gethostbyname of %s failed", bindhost);
+				exit(1);
+			}
+			bcopy(he->h_addr, &ia->sin_addr, he->h_length);
+		}
+	}
+}
+
+void
 usage()
 {
 	(void)fprintf(stderr, "usage: nfsd %s\n", USAGE);