1/* 2 * Routines to authenticate access to a daemon (hosts allow/deny). 3 * 4 * Copyright (C) 1998 Andrew Tridgell 5 * Copyright (C) 2004, 2005 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 2 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, write to the Free Software Foundation, Inc., 19 * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. 20 */ 21 22#include "rsync.h" 23 24static int match_hostname(char *host, char *tok) 25{ 26 if (!host || !*host) 27 return 0; 28 return wildmatch(tok, host); 29} 30 31static int match_binary(char *b1, char *b2, char *mask, int addrlen) 32{ 33 int i; 34 35 for (i = 0; i < addrlen; i++) { 36 if ((b1[i] ^ b2[i]) & mask[i]) 37 return 0; 38 } 39 40 return 1; 41} 42 43static void make_mask(char *mask, int plen, int addrlen) 44{ 45 int w, b; 46 47 w = plen >> 3; 48 b = plen & 0x7; 49 50 if (w) 51 memset(mask, 0xff, w); 52 if (w < addrlen) 53 mask[w] = 0xff & (0xff<<(8-b)); 54 if (w+1 < addrlen) 55 memset(mask+w+1, 0, addrlen-w-1); 56 57 return; 58} 59 60static int match_address(char *addr, char *tok) 61{ 62 char *p; 63 struct addrinfo hints, *resa, *rest; 64 int gai; 65 int ret = 0; 66 int addrlen = 0; 67#ifdef HAVE_STRTOL 68 long int bits; 69#else 70 int bits; 71#endif 72 char mask[16]; 73 char *a = NULL, *t = NULL; 74 unsigned int len; 75 76 if (!addr || !*addr) 77 return 0; 78 79 p = strchr(tok,'/'); 80 if (p) { 81 *p = '\0'; 82 len = p - tok; 83 } else 84 len = strlen(tok); 85 86 /* Fail quietly if tok is a hostname (not an address) */ 87 if (strspn(tok, ".0123456789") != len 88#ifdef INET6 89 && strchr(tok, ':') == NULL 90#endif 91 ) { 92 if (p) 93 *p = '/'; 94 return 0; 95 } 96 97 memset(&hints, 0, sizeof(hints)); 98 hints.ai_family = PF_UNSPEC; 99 hints.ai_socktype = SOCK_STREAM; 100#ifdef AI_NUMERICHOST 101 hints.ai_flags = AI_NUMERICHOST; 102#endif 103 104 if (getaddrinfo(addr, NULL, &hints, &resa) != 0) { 105 if (p) 106 *p = '/'; 107 return 0; 108 } 109 110 gai = getaddrinfo(tok, NULL, &hints, &rest); 111 if (p) 112 *p++ = '/'; 113 if (gai != 0) { 114 rprintf(FLOG, "error matching address %s: %s\n", 115 tok, gai_strerror(gai)); 116 freeaddrinfo(resa); 117 return 0; 118 } 119 120 if (rest->ai_family != resa->ai_family) { 121 ret = 0; 122 goto out; 123 } 124 125 switch(resa->ai_family) { 126 case PF_INET: 127 a = (char *)&((struct sockaddr_in *)resa->ai_addr)->sin_addr; 128 t = (char *)&((struct sockaddr_in *)rest->ai_addr)->sin_addr; 129 addrlen = 4; 130 131 break; 132 133#ifdef INET6 134 case PF_INET6: 135 { 136 struct sockaddr_in6 *sin6a, *sin6t; 137 138 sin6a = (struct sockaddr_in6 *)resa->ai_addr; 139 sin6t = (struct sockaddr_in6 *)rest->ai_addr; 140 141 a = (char *)&sin6a->sin6_addr; 142 t = (char *)&sin6t->sin6_addr; 143 144 addrlen = 16; 145 146#ifdef HAVE_SOCKADDR_IN6_SCOPE_ID 147 if (sin6t->sin6_scope_id && 148 sin6a->sin6_scope_id != sin6t->sin6_scope_id) { 149 ret = 0; 150 goto out; 151 } 152#endif 153 154 break; 155 } 156#endif 157 default: 158 rprintf(FLOG, "unknown family %u\n", rest->ai_family); 159 ret = 0; 160 goto out; 161 } 162 163 bits = -1; 164 if (p) { 165 if (inet_pton(resa->ai_addr->sa_family, p, mask) <= 0) { 166#ifdef HAVE_STRTOL 167 char *ep = NULL; 168#else 169 unsigned char *pp; 170#endif 171 172#ifdef HAVE_STRTOL 173 bits = strtol(p, &ep, 10); 174 if (!*p || *ep) { 175 rprintf(FLOG, "malformed mask in %s\n", tok); 176 ret = 0; 177 goto out; 178 } 179#else 180 for (pp = (unsigned char *)p; *pp; pp++) { 181 if (!isascii(*pp) || !isdigit(*pp)) { 182 rprintf(FLOG, "malformed mask in %s\n", tok); 183 ret = 0; 184 goto out; 185 } 186 } 187 bits = atoi(p); 188#endif 189 if (bits == 0) { 190 ret = 1; 191 goto out; 192 } 193 if (bits < 0 || bits > (addrlen << 3)) { 194 rprintf(FLOG, "malformed mask in %s\n", tok); 195 ret = 0; 196 goto out; 197 } 198 } 199 } else { 200 bits = 128; 201 } 202 203 if (bits >= 0) 204 make_mask(mask, bits, addrlen); 205 206 ret = match_binary(a, t, mask, addrlen); 207 208 out: 209 freeaddrinfo(resa); 210 freeaddrinfo(rest); 211 return ret; 212} 213 214static int access_match(char *list, char *addr, char *host) 215{ 216 char *tok; 217 char *list2 = strdup(list); 218 219 if (!list2) 220 out_of_memory("access_match"); 221 222 strlower(list2); 223 if (host) 224 strlower(host); 225 226 for (tok = strtok(list2, " ,\t"); tok; tok = strtok(NULL, " ,\t")) { 227 if (match_hostname(host, tok) || match_address(addr, tok)) { 228 free(list2); 229 return 1; 230 } 231 } 232 233 free(list2); 234 return 0; 235} 236 237int allow_access(char *addr, char *host, char *allow_list, char *deny_list) 238{ 239 if (allow_list && !*allow_list) 240 allow_list = NULL; 241 if (deny_list && !*deny_list) 242 deny_list = NULL; 243 244 /* If we match an allow-list item, we always allow access. */ 245 if (allow_list) { 246 if (access_match(allow_list, addr, host)) 247 return 1; 248 /* For an allow-list w/o a deny-list, disallow non-matches. */ 249 if (!deny_list) 250 return 0; 251 } 252 253 /* If we match a deny-list item (and got past any allow-list 254 * items), we always disallow access. */ 255 if (deny_list && access_match(deny_list, addr, host)) 256 return 0; 257 258 /* Allow all other access. */ 259 return 1; 260} 261