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;
37 /* First check if the reverse-DNS-determined hostname matches. */
38 if (iwildmatch(tok, host))
41 if (!allow_forward_dns)
44 /* Fail quietly if tok is an address or wildcarded entry, not a simple hostname. */
45 if (!tok[strspn(tok, ".0123456789")] || tok[strcspn(tok, ":/*?[")])
48 /* Now try forward-DNS on the token (config-specified hostname) and see if the IP matches. */
49 if (!(hp = gethostbyname(tok)))
52 for (i = 0; hp->h_addr_list[i] != NULL; i++) {
53 if (strcmp(addr, inet_ntoa(*(struct in_addr*)(hp->h_addr_list[i]))) == 0) {
54 /* If reverse lookups are off, we'll use the conf-specified
55 * hostname in preference to UNDETERMINED. */
56 if (host == undetermined_hostname)
57 *host_ptr = strdup(tok);
65 static int match_binary(const char *b1, const char *b2, const char *mask, int addrlen)
69 for (i = 0; i < addrlen; i++) {
70 if ((b1[i] ^ b2[i]) & mask[i])
77 static void make_mask(char *mask, int plen, int addrlen)
85 memset(mask, 0xff, w);
87 mask[w] = 0xff & (0xff<<(8-b));
89 memset(mask+w+1, 0, addrlen-w-1);
94 static int match_address(const char *addr, const char *tok)
97 struct addrinfo hints, *resa, *rest;
107 char *a = NULL, *t = NULL;
116 /* Fail quietly if tok is a hostname, not an address. */
117 if (tok[strspn(tok, ".0123456789")] && strchr(tok, ':') == NULL) {
123 memset(&hints, 0, sizeof(hints));
124 hints.ai_family = PF_UNSPEC;
125 hints.ai_socktype = SOCK_STREAM;
126 #ifdef AI_NUMERICHOST
127 hints.ai_flags = AI_NUMERICHOST;
130 if (getaddrinfo(addr, NULL, &hints, &resa) != 0) {
136 gai = getaddrinfo(tok, NULL, &hints, &rest);
140 rprintf(FLOG, "error matching address %s: %s\n",
141 tok, gai_strerror(gai));
146 if (rest->ai_family != resa->ai_family) {
151 switch(resa->ai_family) {
153 a = (char *)&((struct sockaddr_in *)resa->ai_addr)->sin_addr;
154 t = (char *)&((struct sockaddr_in *)rest->ai_addr)->sin_addr;
161 struct sockaddr_in6 *sin6a, *sin6t;
163 sin6a = (struct sockaddr_in6 *)resa->ai_addr;
164 sin6t = (struct sockaddr_in6 *)rest->ai_addr;
166 a = (char *)&sin6a->sin6_addr;
167 t = (char *)&sin6t->sin6_addr;
171 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
172 if (sin6t->sin6_scope_id && sin6a->sin6_scope_id != sin6t->sin6_scope_id) {
182 rprintf(FLOG, "unknown family %u\n", rest->ai_family);
189 if (inet_pton(resa->ai_addr->sa_family, p, mask) <= 0) {
197 bits = strtol(p, &ep, 10);
199 rprintf(FLOG, "malformed mask in %s\n", tok);
204 for (pp = (unsigned char *)p; *pp; pp++) {
205 if (!isascii(*pp) || !isdigit(*pp)) {
206 rprintf(FLOG, "malformed mask in %s\n", tok);
217 if (bits < 0 || bits > (addrlen << 3)) {
218 rprintf(FLOG, "malformed mask in %s\n", tok);
228 make_mask(mask, bits, addrlen);
230 ret = match_binary(a, t, mask, addrlen);
238 static int access_match(const char *list, const char *addr, const char **host_ptr)
241 char *list2 = strdup(list);
245 for (tok = strtok(list2, " ,\t"); tok; tok = strtok(NULL, " ,\t")) {
246 if (match_hostname(host_ptr, addr, tok) || match_address(addr, tok)) {
256 int allow_access(const char *addr, const char **host_ptr, int i)
258 const char *allow_list = lp_hosts_allow(i);
259 const char *deny_list = lp_hosts_deny(i);
261 if (allow_list && !*allow_list)
263 if (deny_list && !*deny_list)
266 allow_forward_dns = lp_forward_lookup(i);
268 /* If we match an allow-list item, we always allow access. */
270 if (access_match(allow_list, addr, host_ptr))
272 /* For an allow-list w/o a deny-list, disallow non-matches. */
277 /* If we match a deny-list item (and got past any allow-list
278 * items), we always disallow access. */
279 if (deny_list && access_match(deny_list, addr, host_ptr))
282 /* Allow all other access. */