2 * Routines to authenticate access to a daemon (hosts allow/deny).
4 * Copyright (C) 1998 Andrew Tridgell
5 * Copyright (C) 2004-2020 Wayne Davison
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, visit the http://fsf.org website.
24 static int allow_forward_dns;
26 extern const char undetermined_hostname[];
28 static int match_hostname(const char **host_ptr, const char *addr, const char *tok)
32 const char *host = *host_ptr;
38 if (*tok == '@' && tok[1])
39 return innetgr(tok + 1, host, NULL, NULL);
42 /* First check if the reverse-DNS-determined hostname matches. */
43 if (iwildmatch(tok, host))
46 if (!allow_forward_dns)
49 /* Fail quietly if tok is an address or wildcarded entry, not a simple hostname. */
50 if (!tok[strspn(tok, ".0123456789")] || tok[strcspn(tok, ":/*?[")])
53 /* Now try forward-DNS on the token (config-specified hostname) and see if the IP matches. */
54 if (!(hp = gethostbyname(tok)))
57 for (i = 0; hp->h_addr_list[i] != NULL; i++) {
58 if (strcmp(addr, inet_ntoa(*(struct in_addr*)(hp->h_addr_list[i]))) == 0) {
59 /* If reverse lookups are off, we'll use the conf-specified
60 * hostname in preference to UNDETERMINED. */
61 if (host == undetermined_hostname)
62 *host_ptr = strdup(tok);
70 static int match_binary(const char *b1, const char *b2, const char *mask, int addrlen)
74 for (i = 0; i < addrlen; i++) {
75 if ((b1[i] ^ b2[i]) & mask[i])
82 static void make_mask(char *mask, int plen, int addrlen)
90 memset(mask, 0xff, w);
92 mask[w] = 0xff & (0xff<<(8-b));
94 memset(mask+w+1, 0, addrlen-w-1);
99 static int match_address(const char *addr, const char *tok)
102 struct addrinfo hints, *resa, *rest;
112 char *a = NULL, *t = NULL;
121 /* Fail quietly if tok is a hostname, not an address. */
122 if (tok[strspn(tok, ".0123456789")] && strchr(tok, ':') == NULL) {
128 memset(&hints, 0, sizeof(hints));
129 hints.ai_family = PF_UNSPEC;
130 hints.ai_socktype = SOCK_STREAM;
131 #ifdef AI_NUMERICHOST
132 hints.ai_flags = AI_NUMERICHOST;
135 if (getaddrinfo(addr, NULL, &hints, &resa) != 0) {
141 gai = getaddrinfo(tok, NULL, &hints, &rest);
145 rprintf(FLOG, "error matching address %s: %s\n",
146 tok, gai_strerror(gai));
151 if (rest->ai_family != resa->ai_family) {
156 switch(resa->ai_family) {
158 a = (char *)&((struct sockaddr_in *)resa->ai_addr)->sin_addr;
159 t = (char *)&((struct sockaddr_in *)rest->ai_addr)->sin_addr;
166 struct sockaddr_in6 *sin6a, *sin6t;
168 sin6a = (struct sockaddr_in6 *)resa->ai_addr;
169 sin6t = (struct sockaddr_in6 *)rest->ai_addr;
171 a = (char *)&sin6a->sin6_addr;
172 t = (char *)&sin6t->sin6_addr;
176 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
177 if (sin6t->sin6_scope_id && sin6a->sin6_scope_id != sin6t->sin6_scope_id) {
187 rprintf(FLOG, "unknown family %u\n", rest->ai_family);
194 if (inet_pton(resa->ai_addr->sa_family, p, mask) <= 0) {
202 bits = strtol(p, &ep, 10);
204 rprintf(FLOG, "malformed mask in %s\n", tok);
209 for (pp = (unsigned char *)p; *pp; pp++) {
210 if (!isascii(*pp) || !isdigit(*pp)) {
211 rprintf(FLOG, "malformed mask in %s\n", tok);
222 if (bits < 0 || bits > (addrlen << 3)) {
223 rprintf(FLOG, "malformed mask in %s\n", tok);
233 make_mask(mask, bits, addrlen);
235 ret = match_binary(a, t, mask, addrlen);
243 static int access_match(const char *list, const char *addr, const char **host_ptr)
246 char *list2 = strdup(list);
250 for (tok = strtok(list2, " ,\t"); tok; tok = strtok(NULL, " ,\t")) {
251 if (match_hostname(host_ptr, addr, tok) || match_address(addr, tok)) {
261 int allow_access(const char *addr, const char **host_ptr, int i)
263 const char *allow_list = lp_hosts_allow(i);
264 const char *deny_list = lp_hosts_deny(i);
266 if (allow_list && !*allow_list)
268 if (deny_list && !*deny_list)
271 allow_forward_dns = lp_forward_lookup(i);
273 /* If we match an allow-list item, we always allow access. */
275 if (access_match(allow_list, addr, host_ptr))
277 /* For an allow-list w/o a deny-list, disallow non-matches. */
282 /* If we match a deny-list item (and got past any allow-list
283 * items), we always disallow access. */
284 if (deny_list && access_match(deny_list, addr, host_ptr))
287 /* Allow all other access. */