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.
30 * Author: Wietse Venema (wietse@wzv.win.tue.nl), dept. of Mathematics and
31 * Computing Science, Eindhoven University of Technology, The Netherlands.
37 #include <tcpwrapper.h>
41 #include <rpc/pmap_prot.h>
45 #include <sys/types.h>
46 #include <sys/signal.h>
47 #include <sys/queue.h>
54 #include <netinet/in.h>
55 #include <rpc/rpcent.h>
58 static void logit(int severity, struct sockaddr_in *addr,
59 u_long procnum, u_long prognum, char *text);
60 static void toggle_verboselog(int sig);
61 static int check_files(void);
64 int allow_severity = LOG_INFO;
65 int deny_severity = LOG_WARNING;
67 /* A handful of macros for "readability". */
70 /* coming from libwrap.a (tcp_wrappers) */
71 extern int hosts_ctl(char *daemon, char *name, char *addr, char *user);
73 int hosts_ctl(char *daemon, char *name, char *addr, char *user)
79 #define legal_port(a,p) \
80 (ntohs((a)->sin_port) < IPPORT_RESERVED || (p) >= IPPORT_RESERVED)
82 #define log_bad_port(addr, proc, prog) \
83 logit(deny_severity, addr, proc, prog, ": request from unprivileged port")
85 #define log_bad_host(addr, proc, prog) \
86 logit(deny_severity, addr, proc, prog, ": request from unauthorized host")
88 #define log_bad_owner(addr, proc, prog) \
89 logit(deny_severity, addr, proc, prog, ": request from non-local host")
91 #define log_no_forward(addr, proc, prog) \
92 logit(deny_severity, addr, proc, prog, ": request not forwarded")
94 #define log_client(addr, proc, prog) \
95 logit(allow_severity, addr, proc, prog, "")
100 typedef struct _haccess_t {
101 TAILQ_ENTRY(_haccess_t) list;
106 #define HASH_TABLE_SIZE 1021
107 typedef struct _hash_head {
108 TAILQ_HEAD(host_list, _haccess_t) h_head;
110 hash_head haccess_tbl[HASH_TABLE_SIZE];
111 static haccess_t *haccess_lookup(struct sockaddr_in *addr, u_long);
112 static void haccess_add(struct sockaddr_in *addr, u_long, int);
114 inline unsigned int strtoint(char *str)
117 int len = strlen(str);
120 for (i=0; i < len; i++)
125 static inline int hashint(unsigned int num)
127 return num % HASH_TABLE_SIZE;
129 #define HASH(_addr, _prog) \
130 hashint((strtoint((_addr))+(_prog)))
132 void haccess_add(struct sockaddr_in *addr, u_long prog, int access)
138 hptr = (haccess_t *)malloc(sizeof(haccess_t));
142 hash = HASH(inet_ntoa(addr->sin_addr), prog);
143 head = &(haccess_tbl[hash]);
145 hptr->access = access;
146 hptr->addr.s_addr = addr->sin_addr.s_addr;
148 if (TAILQ_EMPTY(&head->h_head))
149 TAILQ_INSERT_HEAD(&head->h_head, hptr, list);
151 TAILQ_INSERT_TAIL(&head->h_head, hptr, list);
153 haccess_t *haccess_lookup(struct sockaddr_in *addr, u_long prog)
159 hash = HASH(inet_ntoa(addr->sin_addr), prog);
160 head = &(haccess_tbl[hash]);
162 TAILQ_FOREACH(hptr, &head->h_head, list) {
163 if (hptr->addr.s_addr == addr->sin_addr.s_addr)
170 good_client(daemon, addr)
172 struct sockaddr_in *addr;
174 struct request_info req;
176 request_init(&req, RQ_DAEMON, daemon, RQ_CLIENT_SIN, addr, 0);
179 if (hosts_access(&req))
185 /* check_startup - additional startup code */
187 void check_startup(void)
191 * Give up root privileges so that we can never allocate a privileged
192 * port when forwarding an rpc request.
194 * Fix 8/3/00 Philipp Knirsch: First lookup our rpc user. If we find it,
195 * switch to that uid, otherwise simply resue the old bin user and print
196 * out a warning in syslog.
199 struct passwd *pwent;
201 pwent = getpwnam("rpc");
203 syslog(LOG_WARNING, "user rpc not found, reverting to user bin");
204 if (setuid(1) == -1) {
205 syslog(LOG_ERR, "setuid(1) failed: %m");
210 if (setuid(pwent->pw_uid) == -1) {
211 syslog(LOG_WARNING, "setuid() to rpc user failed: %m");
212 if (setuid(1) == -1) {
213 syslog(LOG_ERR, "setuid(1) failed: %m");
219 (void) signal(SIGINT, toggle_verboselog);
222 /* check_files - check to see if either access files have changed */
224 static int check_files()
226 static time_t allow_mtime, deny_mtime;
227 struct stat astat, dstat;
230 if (stat("/etc/hosts.allow", &astat) < 0)
232 if (stat("/etc/hosts.deny", &dstat) < 0)
235 if(!astat.st_mtime || !dstat.st_mtime)
238 if (astat.st_mtime != allow_mtime)
240 else if (dstat.st_mtime != deny_mtime)
243 allow_mtime = astat.st_mtime;
244 deny_mtime = dstat.st_mtime;
249 /* check_default - additional checks for NULL, DUMP, GETPORT and unknown */
252 check_default(daemon, addr, proc, prog)
254 struct sockaddr_in *addr;
258 haccess_t *acc = NULL;
259 int changed = check_files();
261 acc = haccess_lookup(addr, prog);
262 if (acc && changed == 0)
263 return (acc->access);
265 if (!(from_local(addr) || good_client(daemon, addr))) {
266 log_bad_host(addr, proc, prog);
270 haccess_add(addr, prog, FALSE);
274 log_client(addr, proc, prog);
279 haccess_add(addr, prog, TRUE);
283 /* check_privileged_port - additional checks for privileged-port updates */
285 check_privileged_port(struct sockaddr_in *addr,
286 u_long proc, u_long prog, u_long port)
289 if (!legal_port(addr, port)) {
290 log_bad_port(addr, proc, prog);
297 /* toggle_verboselog - toggle verbose logging flag */
299 static void toggle_verboselog(int sig)
301 (void) signal(sig, toggle_verboselog);
302 verboselog = !verboselog;
305 /* logit - report events of interest via the syslog daemon */
307 static void logit(int severity, struct sockaddr_in *addr,
308 u_long procnum, u_long prognum, char *text)
311 char procbuf[16 + 4 * sizeof(u_long)];
313 char progbuf[16 + 4 * sizeof(u_long)];
317 * Fork off a process or the portmap daemon might hang while
318 * getrpcbynumber() or syslog() does its thing.
320 * Don't forget to wait for the children, too...
325 /* Try to map program number to name. */
329 } else if ((rpc = getrpcbynumber((int) prognum))) {
330 progname = rpc->r_name;
332 snprintf(progname = progbuf, sizeof (progbuf),
333 "prog (%lu)", prognum);
336 /* Try to map procedure number to name. */
338 snprintf(procname = procbuf, sizeof (procbuf),
339 "proc (%lu)", (u_long) procnum);
341 /* Write syslog record. */
343 syslog(severity, "connect from %s to %s in %s%s",
344 inet_ntoa(addr->sin_addr), procname, progname, text);