1: /*
2: * Routines to authenticate access to a daemon (hosts allow/deny).
3: *
4: * Copyright (C) 1998 Andrew Tridgell
5: * Copyright (C) 2004-2013 Wayne Davison
6: *
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.
11: *
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.
16: *
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.
19: */
20:
21: #include "rsync.h"
22:
23: static int allow_forward_dns;
24:
25: extern const char undetermined_hostname[];
26:
27: static int match_hostname(const char **host_ptr, const char *addr, const char *tok)
28: {
29: struct hostent *hp;
30: unsigned int i;
31: const char *host = *host_ptr;
32:
33: if (!host || !*host)
34: return 0;
35:
36: /* First check if the reverse-DNS-determined hostname matches. */
37: if (iwildmatch(tok, host))
38: return 1;
39:
40: if (!allow_forward_dns)
41: return 0;
42:
43: /* Fail quietly if tok is an address or wildcarded entry, not a simple hostname. */
44: if (!tok[strspn(tok, ".0123456789")] || tok[strcspn(tok, ":/*?[")])
45: return 0;
46:
47: /* Now try forward-DNS on the token (config-specified hostname) and see if the IP matches. */
48: if (!(hp = gethostbyname(tok)))
49: return 0;
50:
51: for (i = 0; hp->h_addr_list[i] != NULL; i++) {
52: if (strcmp(addr, inet_ntoa(*(struct in_addr*)(hp->h_addr_list[i]))) == 0) {
53: /* If reverse lookups are off, we'll use the conf-specified
54: * hostname in preference to UNDETERMINED. */
55: if (host == undetermined_hostname) {
56: if (!(*host_ptr = strdup(tok)))
57: *host_ptr = undetermined_hostname;
58: }
59: return 1;
60: }
61: }
62:
63: return 0;
64: }
65:
66: static int match_binary(const char *b1, const char *b2, const char *mask, int addrlen)
67: {
68: int i;
69:
70: for (i = 0; i < addrlen; i++) {
71: if ((b1[i] ^ b2[i]) & mask[i])
72: return 0;
73: }
74:
75: return 1;
76: }
77:
78: static void make_mask(char *mask, int plen, int addrlen)
79: {
80: int w, b;
81:
82: w = plen >> 3;
83: b = plen & 0x7;
84:
85: if (w)
86: memset(mask, 0xff, w);
87: if (w < addrlen)
88: mask[w] = 0xff & (0xff<<(8-b));
89: if (w+1 < addrlen)
90: memset(mask+w+1, 0, addrlen-w-1);
91:
92: return;
93: }
94:
95: static int match_address(const char *addr, const char *tok)
96: {
97: char *p;
98: struct addrinfo hints, *resa, *rest;
99: int gai;
100: int ret = 0;
101: int addrlen = 0;
102: #ifdef HAVE_STRTOL
103: long int bits;
104: #else
105: int bits;
106: #endif
107: char mask[16];
108: char *a = NULL, *t = NULL;
109:
110: if (!addr || !*addr)
111: return 0;
112:
113: p = strchr(tok,'/');
114: if (p)
115: *p = '\0';
116:
117: /* Fail quietly if tok is a hostname, not an address. */
118: if (tok[strspn(tok, ".0123456789")] && strchr(tok, ':') == NULL) {
119: if (p)
120: *p = '/';
121: return 0;
122: }
123:
124: memset(&hints, 0, sizeof(hints));
125: hints.ai_family = PF_UNSPEC;
126: hints.ai_socktype = SOCK_STREAM;
127: #ifdef AI_NUMERICHOST
128: hints.ai_flags = AI_NUMERICHOST;
129: #endif
130:
131: if (getaddrinfo(addr, NULL, &hints, &resa) != 0) {
132: if (p)
133: *p = '/';
134: return 0;
135: }
136:
137: gai = getaddrinfo(tok, NULL, &hints, &rest);
138: if (p)
139: *p++ = '/';
140: if (gai != 0) {
141: rprintf(FLOG, "error matching address %s: %s\n",
142: tok, gai_strerror(gai));
143: freeaddrinfo(resa);
144: return 0;
145: }
146:
147: if (rest->ai_family != resa->ai_family) {
148: ret = 0;
149: goto out;
150: }
151:
152: switch(resa->ai_family) {
153: case PF_INET:
154: a = (char *)&((struct sockaddr_in *)resa->ai_addr)->sin_addr;
155: t = (char *)&((struct sockaddr_in *)rest->ai_addr)->sin_addr;
156: addrlen = 4;
157:
158: break;
159:
160: #ifdef INET6
161: case PF_INET6:
162: {
163: struct sockaddr_in6 *sin6a, *sin6t;
164:
165: sin6a = (struct sockaddr_in6 *)resa->ai_addr;
166: sin6t = (struct sockaddr_in6 *)rest->ai_addr;
167:
168: a = (char *)&sin6a->sin6_addr;
169: t = (char *)&sin6t->sin6_addr;
170:
171: addrlen = 16;
172:
173: #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
174: if (sin6t->sin6_scope_id &&
175: sin6a->sin6_scope_id != sin6t->sin6_scope_id) {
176: ret = 0;
177: goto out;
178: }
179: #endif
180:
181: break;
182: }
183: #endif
184: default:
185: rprintf(FLOG, "unknown family %u\n", rest->ai_family);
186: ret = 0;
187: goto out;
188: }
189:
190: bits = -1;
191: if (p) {
192: if (inet_pton(resa->ai_addr->sa_family, p, mask) <= 0) {
193: #ifdef HAVE_STRTOL
194: char *ep = NULL;
195: #else
196: unsigned char *pp;
197: #endif
198:
199: #ifdef HAVE_STRTOL
200: bits = strtol(p, &ep, 10);
201: if (!*p || *ep) {
202: rprintf(FLOG, "malformed mask in %s\n", tok);
203: ret = 0;
204: goto out;
205: }
206: #else
207: for (pp = (unsigned char *)p; *pp; pp++) {
208: if (!isascii(*pp) || !isdigit(*pp)) {
209: rprintf(FLOG, "malformed mask in %s\n", tok);
210: ret = 0;
211: goto out;
212: }
213: }
214: bits = atoi(p);
215: #endif
216: if (bits == 0) {
217: ret = 1;
218: goto out;
219: }
220: if (bits < 0 || bits > (addrlen << 3)) {
221: rprintf(FLOG, "malformed mask in %s\n", tok);
222: ret = 0;
223: goto out;
224: }
225: }
226: } else {
227: bits = 128;
228: }
229:
230: if (bits >= 0)
231: make_mask(mask, bits, addrlen);
232:
233: ret = match_binary(a, t, mask, addrlen);
234:
235: out:
236: freeaddrinfo(resa);
237: freeaddrinfo(rest);
238: return ret;
239: }
240:
241: static int access_match(const char *list, const char *addr, const char **host_ptr)
242: {
243: char *tok;
244: char *list2 = strdup(list);
245:
246: if (!list2)
247: out_of_memory("access_match");
248:
249: strlower(list2);
250:
251: for (tok = strtok(list2, " ,\t"); tok; tok = strtok(NULL, " ,\t")) {
252: if (match_hostname(host_ptr, addr, tok) || match_address(addr, tok)) {
253: free(list2);
254: return 1;
255: }
256: }
257:
258: free(list2);
259: return 0;
260: }
261:
262: int allow_access(const char *addr, const char **host_ptr, int i)
263: {
264: const char *allow_list = lp_hosts_allow(i);
265: const char *deny_list = lp_hosts_deny(i);
266:
267: if (allow_list && !*allow_list)
268: allow_list = NULL;
269: if (deny_list && !*deny_list)
270: deny_list = NULL;
271:
272: allow_forward_dns = lp_forward_lookup(i);
273:
274: /* If we match an allow-list item, we always allow access. */
275: if (allow_list) {
276: if (access_match(allow_list, addr, host_ptr))
277: return 1;
278: /* For an allow-list w/o a deny-list, disallow non-matches. */
279: if (!deny_list)
280: return 0;
281: }
282:
283: /* If we match a deny-list item (and got past any allow-list
284: * items), we always disallow access. */
285: if (deny_list && access_match(deny_list, addr, host_ptr))
286: return 0;
287:
288: /* Allow all other access. */
289: return 1;
290: }
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