2 * pmap_check - additional portmap security.
4 * Always reject non-local requests to update the portmapper tables.
6 * Refuse to forward mount requests to the nfs mount daemon. Otherwise, the
7 * requests would appear to come from the local system, and nfs export
8 * restrictions could be bypassed.
10 * Refuse to forward requests to the nfsd process.
12 * Refuse to forward requests to NIS (YP) daemons; The only exception is the
13 * YPPROC_DOMAIN_NONACK broadcast rpc call that is used to establish initial
14 * contact with the NIS server.
16 * Always allocate an unprivileged port when forwarding a request.
18 * If compiled with -DCHECK_PORT, require that requests to register or
19 * unregister a privileged port come from a privileged port. This makes it
20 * more difficult to replace a critical service by a trojan.
22 * If compiled with -DHOSTS_ACCESS, reject requests from hosts that are not
23 * authorized by the /etc/hosts.{allow,deny} files. The local system is
24 * always treated as an authorized host. The access control tables are never
25 * consulted for requests from the local system, and are always consulted
26 * for requests from other hosts. Access control is based on IP addresses
27 * only; attempts to map an address to a host name might cause the
30 * Author: Wietse Venema (wietse@wzv.win.tue.nl), dept. of Mathematics and
31 * Computing Science, Eindhoven University of Technology, The Netherlands.
36 static char sccsid[] = "@(#) pmap_check.c 1.6 93/11/21 20:58:59";
38 static const char rcsid[] =
39 "$FreeBSD: src/usr.sbin/portmap/pmap_check.c,v 1.6 2000/01/15 23:08:28 brian Exp $";
44 #include <sys/types.h>
45 #include <sys/socket.h>
46 #include <netinet/in.h>
47 #include <arpa/inet.h>
50 #include <rpc/pmap_prot.h>
53 #include <sys/signal.h>
55 #include "pmap_check.h"
57 /* Explicit #defines in case the include files are not available. */
59 #define NFSPROG ((u_long) 100003)
60 #define MOUNTPROG ((u_long) 100005)
61 #define YPXPROG ((u_long) 100069)
62 #define YPPROG ((u_long) 100004)
63 #define YPPROC_DOMAIN_NONACK ((u_long) 2)
64 #define MOUNTPROC_MNT ((u_long) 1)
66 static void logit __P((int, struct sockaddr_in *, u_long, u_long, const char *));
67 static void toggle_verboselog __P((int));
70 int allow_severity = LOG_INFO;
71 int deny_severity = LOG_WARNING;
73 /* A handful of macros for "readability". */
75 #define good_client(a) hosts_ctl("portmap", "", inet_ntoa(a->sin_addr), "")
77 #define legal_port(a,p) \
78 (ntohs((a)->sin_port) < IPPORT_RESERVED || (p) >= IPPORT_RESERVED)
80 #define log_bad_port(addr, proc, prog) \
81 logit(deny_severity, addr, proc, prog, ": request from unprivileged port")
83 #define log_bad_host(addr, proc, prog) \
84 logit(deny_severity, addr, proc, prog, ": request from unauthorized host")
86 #define log_bad_owner(addr, proc, prog) \
87 logit(deny_severity, addr, proc, prog, ": request from non-local host")
89 #define log_no_forward(addr, proc, prog) \
90 logit(deny_severity, addr, proc, prog, ": request not forwarded")
92 #define log_client(addr, proc, prog) \
93 logit(allow_severity, addr, proc, prog, "")
95 /* check_startup - additional startup code */
102 * Give up root privileges so that we can never allocate a privileged
103 * port when forwarding an rpc request.
105 if (setuid(1) == -1) {
106 syslog(LOG_ERR, "setuid(1) failed: %m");
109 (void) signal(SIGINT, toggle_verboselog);
112 /* check_default - additional checks for NULL, DUMP, GETPORT and unknown */
115 check_default(addr, proc, prog)
116 struct sockaddr_in *addr;
120 if (!(from_local(addr) || good_client(addr))) {
121 log_bad_host(addr, proc, prog);
126 log_client(addr, proc, prog);
130 /* check_privileged_port - additional checks for privileged-port updates */
133 check_privileged_port(addr, proc, prog, port)
134 struct sockaddr_in *addr;
135 u_long proc, prog, port;
138 if (!legal_port(addr, port)) {
139 log_bad_port(addr, proc, prog);
146 /* check_setunset - additional checks for update requests */
149 check_setunset(addr, proc, prog, port)
150 struct sockaddr_in *addr;
151 u_long proc, prog, port;
153 if (!from_local(addr)) {
155 (void) good_client(addr); /* because of side effects */
157 log_bad_owner(addr, proc, prog);
160 if (port && !check_privileged_port(addr, proc, prog, port))
163 log_client(addr, proc, prog);
167 /* check_callit - additional checks for forwarded requests */
170 check_callit(addr, proc, prog, aproc)
171 struct sockaddr_in *addr;
172 u_long proc, prog, aproc;
175 if (!(from_local(addr) || good_client(addr))) {
176 log_bad_host(addr, proc, prog);
180 if (prog == PMAPPROG || prog == NFSPROG || prog == YPXPROG ||
181 (prog == MOUNTPROG && aproc == MOUNTPROC_MNT) ||
182 (prog == YPPROG && aproc != YPPROC_DOMAIN_NONACK)) {
183 log_no_forward(addr, proc, prog);
187 log_client(addr, proc, prog);
191 /* toggle_verboselog - toggle verbose logging flag */
194 toggle_verboselog(sig)
197 (void) signal(sig, toggle_verboselog);
198 verboselog = !verboselog;
201 /* logit - report events of interest via the syslog daemon */
204 logit(severity, addr, procnum, prognum, text)
206 struct sockaddr_in *addr;
207 u_long procnum, prognum;
210 const char *procname;
211 char procbuf[4 * sizeof(u_long)];
212 const char *progname;
213 char progbuf[4 * sizeof(u_long)];
219 struct proc_map *procp;
220 static struct proc_map procmap[] = {
221 {PMAPPROC_CALLIT, "callit"},
222 {PMAPPROC_DUMP, "dump"},
223 {PMAPPROC_GETPORT, "getport"},
224 {PMAPPROC_NULL, "null"},
225 {PMAPPROC_SET, "set"},
226 {PMAPPROC_UNSET, "unset"},
231 * Fork off a process or the portmap daemon might hang while
232 * getrpcbynumber() or syslog() does its thing.
237 /* Try to map program number to name. */
241 } else if ((rpc = getrpcbynumber((int) prognum))) {
242 progname = rpc->r_name;
244 sprintf(progbuf, "%lu", prognum);
248 /* Try to map procedure number to name. */
250 for (procp = procmap; procp->proc && procp->code != procnum; procp++)
252 if ((procname = procp->proc) == 0) {
253 sprintf(procbuf, "%lu", (u_long) procnum);
257 /* Write syslog record. */
259 syslog(severity, "connect from %s to %s(%s)%s",
260 inet_ntoa(addr->sin_addr), procname, progname, text);