1 /* This is copied from portmap 4.0-29 in RedHat. */
4 * pmap_check - additional portmap security.
6 * Always reject non-local requests to update the portmapper tables.
8 * Refuse to forward mount requests to the nfs mount daemon. Otherwise, the
9 * requests would appear to come from the local system, and nfs export
10 * restrictions could be bypassed.
12 * Refuse to forward requests to the nfsd process.
14 * Refuse to forward requests to NIS (YP) daemons; The only exception is the
15 * YPPROC_DOMAIN_NONACK broadcast rpc call that is used to establish initial
16 * contact with the NIS server.
18 * Always allocate an unprivileged port when forwarding a request.
20 * If compiled with -DCHECK_PORT, require that requests to register or
21 * unregister a privileged port come from a privileged port. This makes it
22 * more difficult to replace a critical service by a trojan.
24 * If compiled with -DHOSTS_ACCESS, reject requests from hosts that are not
25 * authorized by the /etc/hosts.{allow,deny} files. The local system is
26 * always treated as an authorized host. The access control tables are never
27 * consulted for requests from the local system, and are always consulted
28 * for requests from other hosts. Access control is based on IP addresses
29 * only; attempts to map an address to a host name might cause the
32 * Author: Wietse Venema (wietse@wzv.win.tue.nl), dept. of Mathematics and
33 * Computing Science, Eindhoven University of Technology, The Netherlands.
36 #include "tcpwrapper.h"
41 #include <rpc/pmap_prot.h>
45 #include <sys/types.h>
46 #include <sys/signal.h>
48 #include <netinet/in.h>
49 #include <rpc/rpcent.h>
53 static void toggle_verboselog();
55 int allow_severity = LOG_INFO;
56 int deny_severity = LOG_WARNING;
58 /* A handful of macros for "readability". */
60 /* coming from libwrap.a (tcp_wrappers) */
61 extern int hosts_ctl(char *daemon, char *name, char *addr, char *user);
63 #define legal_port(a,p) \
64 (ntohs((a)->sin_port) < IPPORT_RESERVED || (p) >= IPPORT_RESERVED)
66 #define log_bad_port(addr, proc, prog) \
67 logit(deny_severity, addr, proc, prog, ": request from unprivileged port")
69 #define log_bad_host(addr, proc, prog) \
70 logit(deny_severity, addr, proc, prog, ": request from unauthorized host")
72 #define log_bad_owner(addr, proc, prog) \
73 logit(deny_severity, addr, proc, prog, ": request from non-local host")
75 #define log_no_forward(addr, proc, prog) \
76 logit(deny_severity, addr, proc, prog, ": request not forwarded")
78 #define log_client(addr, proc, prog) \
79 logit(allow_severity, addr, proc, prog, "")
82 good_client(daemon, addr)
84 struct sockaddr_in *addr;
90 /* Check the IP address first. */
91 if (hosts_ctl(daemon, "", inet_ntoa(addr->sin_addr), ""))
94 /* Check the hostname. */
95 hp = gethostbyaddr ((const char *) &(addr->sin_addr),
96 sizeof (addr->sin_addr), AF_INET);
101 /* must make sure the hostent is authorative. */
102 tmpname = alloca (strlen (hp->h_name) + 1);
103 strcpy (tmpname, hp->h_name);
104 hp = gethostbyname(tmpname);
106 /* now make sure the "addr->sin_addr" is on the list */
107 for (sp = hp->h_addr_list ; *sp ; sp++) {
108 if (memcmp(*sp, &(addr->sin_addr), hp->h_length)==0)
116 /* never heard of it. misconfigured DNS? */
119 /* Check the official name first. */
120 if (hosts_ctl(daemon, "", hp->h_name, ""))
124 for (sp = hp->h_aliases; *sp ; sp++) {
125 if (hosts_ctl(daemon, "", *sp, ""))
133 /* check_startup - additional startup code */
139 * Give up root privileges so that we can never allocate a privileged
140 * port when forwarding an rpc request.
142 * Fix 8/3/00 Philipp Knirsch: First lookup our rpc user. If we find it,
143 * switch to that uid, otherwise simply resue the old bin user and print
144 * out a warning in syslog.
147 struct passwd *pwent;
149 pwent = getpwnam("rpc");
151 syslog(LOG_WARNING, "user rpc not found, reverting to user bin");
152 if (setuid(1) == -1) {
153 syslog(LOG_ERR, "setuid(1) failed: %m");
158 if (setuid(pwent->pw_uid) == -1) {
159 syslog(LOG_WARNING, "setuid() to rpc user failed: %m");
160 if (setuid(1) == -1) {
161 syslog(LOG_ERR, "setuid(1) failed: %m");
167 (void) signal(SIGINT, toggle_verboselog);
170 /* check_default - additional checks for NULL, DUMP, GETPORT and unknown */
173 check_default(daemon, addr, proc, prog)
175 struct sockaddr_in *addr;
179 if (!(from_local(addr) || good_client(daemon, addr))) {
180 log_bad_host(addr, proc, prog);
184 log_client(addr, proc, prog);
188 /* check_privileged_port - additional checks for privileged-port updates */
190 check_privileged_port(addr, proc, prog, port)
191 struct sockaddr_in *addr;
197 if (!legal_port(addr, port)) {
198 log_bad_port(addr, proc, prog);
205 /* toggle_verboselog - toggle verbose logging flag */
207 static void toggle_verboselog(sig)
210 (void) signal(sig, toggle_verboselog);
211 verboselog = !verboselog;
214 /* logit - report events of interest via the syslog daemon */
216 static void logit(severity, addr, procnum, prognum, text)
218 struct sockaddr_in *addr;
224 char procbuf[16 + 4 * sizeof(u_long)];
226 char progbuf[16 + 4 * sizeof(u_long)];
230 * Fork off a process or the portmap daemon might hang while
231 * getrpcbynumber() or syslog() does its thing.
233 * Don't forget to wait for the children, too...
238 /* Try to map program number to name. */
242 } else if ((rpc = getrpcbynumber((int) prognum))) {
243 progname = rpc->r_name;
245 snprintf(progname = progbuf, sizeof (progbuf),
246 "prog (%lu)", prognum);
249 /* Try to map procedure number to name. */
251 snprintf(procname = procbuf, sizeof (procbuf),
252 "proc (%lu)", (u_long) procnum);
254 /* Write syslog record. */
256 syslog(severity, "connect from %s to %s in %s%s",
257 inet_ntoa(addr->sin_addr), procname, progname, text);