2 * Figure out if UNIX passwords are permitted for any combination of user
3 * name, group member, terminal port, host_name or network:
5 * Programmatic interface: skeyaccess(user, port, host, addr)
7 * All arguments are null-terminated strings. Specify a null character pointer
8 * where information is not available.
10 * When no address information is given this code performs the host (internet)
11 * address lookup itself. It rejects addresses that appear to belong to
14 * When compiled with -DPERMIT_CONSOLE always permits UNIX passwords with
15 * console logins, no matter what the configuration file says.
17 * To build a stand-alone test version, compile with -DTEST and run it off an
18 * skey.access file in the current directory:
20 * Command-line interface: ./skeyaccess user port [host_or_ip_addr]
22 * Errors are reported via syslogd.
24 * Author: Wietse Venema, Eindhoven University of Technology.
26 * $FreeBSD: src/lib/libskey/skeyaccess.c,v 1.9.6.2 2002/08/12 19:42:24 iedowse Exp $
27 * $DragonFly: src/lib/libskey/skeyaccess.c,v 1.5 2008/09/30 16:57:05 swildner Exp $
30 #include <sys/types.h>
31 #include <sys/socket.h>
32 #include <netinet/in.h>
35 #include <arpa/inet.h>
43 #include <sys/param.h>
45 #include "pathnames.h"
48 * Token input with one-deep pushback.
50 static char *prev_token = 0; /* push-back buffer */
51 static char *line_pointer = NULL;
52 static char *first_token (char *, int, FILE *);
53 static int line_number;
54 static void unget_token (char *);
55 static char *get_token (void);
56 static char *need_token (void);
57 static char *need_internet_addr (void);
60 * Various forms of token matching.
62 #define match_host_name(l) match_token((l)->host_name)
63 #define match_port(l) match_token((l)->port)
64 #define match_user(l) match_token((l)->user)
66 static int match_internet_addr (struct login_info *);
67 static int match_group (struct login_info *);
68 static int match_token (char *);
69 static int is_internet_addr (char *);
70 static struct addrinfo *convert_internet_addr (char *);
71 static struct addrinfo *lookup_internet_addr (char *);
78 #define CONSOLE "console"
81 #define VTY_PREFIX "ttyv"
85 char *host_name; /* host name */
86 struct addrinfo *internet_addr; /* addrinfo chain */
87 char *user; /* user name */
88 char *port; /* login port */
91 static int _skeyaccess (FILE *, struct login_info *);
92 int skeyaccess (char *, char *, char *, char *);
94 /* skeyaccess - find out if UNIX passwords are permitted */
97 skeyaccess(char *user, char *port, char *host, char *addr)
100 struct login_info login_info;
104 * Assume no restriction on the use of UNIX passwords when the s/key
105 * acces table does not exist.
107 if ((fp = fopen(_PATH_SKEYACCESS, "r")) == 0) {
109 fprintf(stderr, "No file %s, thus no access control\n", _PATH_SKEYACCESS);
115 * Bundle up the arguments in a structure so we won't have to drag around
116 * boring long argument lists.
118 * Look up the host address when only the name is given. We try to reject
119 * addresses that belong to someone else.
121 login_info.user = user;
122 login_info.port = port;
124 if (host != NULL && !is_internet_addr(host)) {
125 login_info.host_name = host;
127 login_info.host_name = NULL;
130 if (addr != NULL && is_internet_addr(addr)) {
131 login_info.internet_addr = convert_internet_addr(addr);
132 } else if (host != NULL) {
133 if (is_internet_addr(host)) {
134 login_info.internet_addr = convert_internet_addr(host);
136 login_info.internet_addr = lookup_internet_addr(host);
139 login_info.internet_addr = NULL;
143 * Print what we think the user wants us to do.
146 printf("port: %s\n", login_info.port);
147 printf("user: %s\n", login_info.user);
148 printf("host: %s\n", login_info.host_name ? login_info.host_name : "none");
150 if (login_info.internet_addr == NULL) {
153 struct addrinfo *res;
154 char haddr[NI_MAXHOST];
156 for (res = login_info.internet_addr; res; res = res->ai_next) {
157 getnameinfo(res->ai_addr, res->ai_addrlen, haddr, sizeof(haddr),
158 NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID);
159 printf("%s%s", haddr, res->ai_next ? " " : "\n");
163 result = _skeyaccess(fp, &login_info);
165 if (login_info.internet_addr)
166 freeaddrinfo(login_info.internet_addr);
170 /* _skeyaccess - find out if UNIX passwords are permitted */
173 _skeyaccess(FILE *fp, struct login_info *login_info)
180 #ifdef PERMIT_CONSOLE
181 if (login_info->port != 0 &&
182 (strcmp(login_info->port, CONSOLE) == 0 ||
183 strncmp(login_info->port, VTY_PREFIX, sizeof(VTY_PREFIX) - 1) == 0
190 * Scan the s/key access table until we find an entry that matches. If no
191 * match is found, assume that UNIX passwords are disallowed.
194 while (match == 0 && (tok = first_token(buf, sizeof(buf), fp))) {
195 if (strncasecmp(tok, "permit", 4) == 0) {
197 } else if (strncasecmp(tok, "deny", 4) == 0) {
200 syslog(LOG_ERR, "%s: line %d: bad permission: %s",
201 _PATH_SKEYACCESS, line_number, tok);
202 continue; /* error */
206 * Process all conditions in this entry until we find one that fails.
209 while (match != 0 && (tok = get_token())) {
210 if (strcasecmp(tok, "hostname") == 0) {
211 match = match_host_name(login_info);
212 } else if (strcasecmp(tok, "port") == 0) {
213 match = match_port(login_info);
214 } else if (strcasecmp(tok, "user") == 0) {
215 match = match_user(login_info);
216 } else if (strcasecmp(tok, "group") == 0) {
217 match = match_group(login_info);
218 } else if (strcasecmp(tok, "internet") == 0) {
219 match = match_internet_addr(login_info);
220 } else if (is_internet_addr(tok)) {
222 match = match_internet_addr(login_info);
224 syslog(LOG_ERR, "%s: line %d: bad condition: %s",
225 _PATH_SKEYACCESS, line_number, tok);
230 return (match ? permission : DENY);
233 /* translate IPv4 mapped IPv6 address to IPv4 address */
236 ai_unmapped(struct addrinfo *ai)
238 struct sockaddr_in6 *sin6;
239 struct sockaddr_in *sin4;
243 if (ai->ai_family != AF_INET6)
245 sin6 = (struct sockaddr_in6 *)ai->ai_addr;
246 if (!IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
248 sin4 = (struct sockaddr_in *)ai->ai_addr;
249 addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12];
250 port = sin6->sin6_port;
251 memset(sin4, 0, sizeof(struct sockaddr_in));
252 sin4->sin_addr.s_addr = addr;
253 sin4->sin_port = port;
254 sin4->sin_family = AF_INET;
255 sin4->sin_len = sizeof(struct sockaddr_in);
256 ai->ai_family = AF_INET;
257 ai->ai_addrlen = sizeof(struct sockaddr_in);
260 /* match_internet_addr - match internet network address */
263 match_internet_addr(struct login_info *login_info)
266 struct addrinfo *res;
267 struct sockaddr_storage pattern, mask;
268 struct sockaddr_in *addr4, *pattern4, *mask4;
269 struct sockaddr_in6 *addr6, *pattern6, *mask6;
272 if (login_info->internet_addr == NULL)
274 if ((tok = need_internet_addr()) == 0)
276 if ((res = convert_internet_addr(tok)) == NULL)
278 memcpy(&pattern, res->ai_addr, res->ai_addrlen);
280 if ((tok = need_internet_addr()) == 0)
282 if ((res = convert_internet_addr(tok)) == NULL)
284 memcpy(&mask, res->ai_addr, res->ai_addrlen);
286 if (pattern.ss_family != mask.ss_family)
288 mask4 = (struct sockaddr_in *)&mask;
289 pattern4 = (struct sockaddr_in *)&pattern;
290 mask6 = (struct sockaddr_in6 *)&mask;
291 pattern6 = (struct sockaddr_in6 *)&pattern;
294 * See if any of the addresses matches a pattern in the control file. We
295 * have already tried to drop addresses that belong to someone else.
298 for (res = login_info->internet_addr; res; res = res->ai_next) {
300 if (res->ai_family != pattern.ss_family)
302 switch (res->ai_family) {
304 addr4 = (struct sockaddr_in *)res->ai_addr;
305 if (addr4->sin_addr.s_addr != INADDR_NONE &&
306 (addr4->sin_addr.s_addr & mask4->sin_addr.s_addr) == pattern4->sin_addr.s_addr)
310 addr6 = (struct sockaddr_in6 *)res->ai_addr;
311 if (pattern6->sin6_scope_id != 0 &&
312 addr6->sin6_scope_id != pattern6->sin6_scope_id)
315 for (i = 0; i < 16; ++i) {
316 if ((addr6->sin6_addr.s6_addr[i] & mask6->sin6_addr.s6_addr[i]) != pattern6->sin6_addr.s6_addr[i]) {
329 /* match_group - match username against group */
332 match_group(struct login_info *login_info)
334 struct passwd *passwd;
339 if ((tok = need_token()) &&
340 (passwd = getpwnam(login_info->user)) && (group = getgrnam(tok))) {
341 if (passwd->pw_gid == (gid_t)group->gr_gid)
343 for (memp = group->gr_mem; *memp; memp++)
344 if (strcmp(login_info->user, *memp) == 0)
347 return (0); /* XXX endgrent() */
350 /* match_token - get and match token */
353 match_token(char *str)
357 return (str && (tok = need_token()) && strcasecmp(str, tok) == 0);
360 /* first_token - read line and return first token */
363 first_token(char *buf, int len, FILE *fp)
369 if (fgets(buf, len, fp) == 0)
372 buf[strcspn(buf, "\r\n#")] = 0;
375 printf("rule: %s\n", buf);
378 while ((cp = strsep(&line_pointer, " \t")) != NULL && *cp == '\0')
385 /* unget_token - push back last token */
388 unget_token(char *cp)
393 /* get_token - retrieve next token from buffer */
400 if ( (cp = prev_token) ) {
403 while ((cp = strsep(&line_pointer, " \t")) != NULL && *cp == '\0')
409 /* need_token - complain if next token is not available */
416 if ((cp = get_token()) == 0)
417 syslog(LOG_ERR, "%s: line %d: premature end of rule",
418 _PATH_SKEYACCESS, line_number);
422 /* need_internet_addr - complain if next token is not an internet address */
425 need_internet_addr(void)
429 if ((cp = get_token()) == 0) {
430 syslog(LOG_ERR, "%s: line %d: internet address expected",
431 _PATH_SKEYACCESS, line_number);
433 } else if (!is_internet_addr(cp)) {
434 syslog(LOG_ERR, "%s: line %d: bad internet address: %s",
435 _PATH_SKEYACCESS, line_number, cp);
442 /* is_internet_addr - determine if string is a dotted quad decimal address */
445 is_internet_addr(char *str)
447 struct addrinfo *res;
449 if ((res = convert_internet_addr(str)) != NULL)
451 return (res != NULL);
455 * Nuke addrinfo entry from list.
456 * XXX: Depending on the implementation of KAME's getaddrinfo(3).
459 nuke_ai(struct addrinfo **aip)
465 if (ai->ai_canonname) {
466 if (ai->ai_next && !ai->ai_next->ai_canonname)
467 ai->ai_next->ai_canonname = ai->ai_canonname;
469 free(ai->ai_canonname);
474 /* lookup_internet_addr - look up internet addresses with extreme prejudice */
476 static struct addrinfo *
477 lookup_internet_addr(char *host)
479 struct addrinfo hints, *res0, *res, **resp;
480 char hname[NI_MAXHOST], haddr[NI_MAXHOST];
483 memset(&hints, 0, sizeof(hints));
484 hints.ai_family = PF_UNSPEC;
485 hints.ai_socktype = SOCK_STREAM;
486 hints.ai_flags = AI_PASSIVE | AI_CANONNAME;
487 if (getaddrinfo(host, NULL, &hints, &res0) != 0)
489 if (res0->ai_canonname == NULL) {
495 * Wipe addresses that appear to belong to someone else. We will get
496 * false alarms when when the hostname comes from DNS, while its
497 * addresses are listed under different names in local databases.
499 #define NEQ(x,y) (strcasecmp((x),(y)) != 0)
500 #define NEQ3(x,y,n) (strncasecmp((x),(y), (n)) != 0)
503 while ((res = *resp) != NULL) {
504 if (res->ai_family != AF_INET && res->ai_family != AF_INET6) {
508 error = getnameinfo(res->ai_addr, res->ai_addrlen,
509 hname, sizeof(hname),
510 NULL, 0, NI_NAMEREQD | NI_WITHSCOPEID);
512 getnameinfo(res->ai_addr, res->ai_addrlen, haddr, sizeof(haddr),
513 NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID);
514 syslog(LOG_ERR, "address %s not registered for host %s",
515 haddr, res0->ai_canonname);
519 if (NEQ(res0->ai_canonname, hname) &&
520 NEQ3(res0->ai_canonname, "localhost.", 10)) {
521 getnameinfo(res->ai_addr, res->ai_addrlen, haddr, sizeof(haddr),
522 NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID);
523 syslog(LOG_ERR, "address %s registered for host %s and %s",
524 haddr, hname, res0->ai_canonname);
528 resp = &res->ai_next;
533 /* convert_internet_addr - convert string to internet address */
535 static struct addrinfo *
536 convert_internet_addr(char *string)
538 struct addrinfo hints, *res;
540 memset(&hints, 0, sizeof(hints));
541 hints.ai_family = PF_UNSPEC;
542 hints.ai_socktype = SOCK_STREAM;
543 hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST;
544 if (getaddrinfo(string, NULL, &hints, &res) != 0)
552 main(int argc, char **argv)
554 struct addrinfo hints, *res;
555 char host[MAXHOSTNAMELEN + 1];
560 if (argc != 3 && argc != 4) {
561 fprintf(stderr, "usage: %s user port [host_or_ip_address]\n", argv[0]);
564 if (_PATH_SKEYACCESS[0] != '/')
565 printf("Warning: this program uses control file: %s\n", _PATH_SKEYACCESS);
566 openlog("login", LOG_PID, LOG_AUTH);
571 memset(&hints, 0, sizeof(hints));
572 hints.ai_family = PF_UNSPEC;
573 hints.ai_socktype = SOCK_STREAM;
574 hints.ai_flags = AI_PASSIVE | AI_CANONNAME;
575 if (getaddrinfo(argv[3], NULL, &hints, &res) == 0) {
576 if (res->ai_canonname == NULL)
577 strncpy(host, argv[3], MAXHOSTNAMELEN);
579 strncpy(host, res->ai_canonname, MAXHOSTNAMELEN);
582 strncpy(host, argv[3], MAXHOSTNAMELEN);
583 host[MAXHOSTNAMELEN] = 0;
585 verdict = skeyaccess(user, port, argv[3] ? host : (char *) 0, (char *) 0);
586 printf("UNIX passwords %spermitted\n", verdict ? "" : "NOT ");