| 1 | /* |
| 2 | * Routines to authenticate access to a daemon (hosts allow/deny). |
| 3 | * |
| 4 | * Copyright (C) 1998 Andrew Tridgell |
| 5 | * Copyright (C) 2004-2008 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 match_hostname(char *host, char *tok) |
| 24 | { |
| 25 | if (!host || !*host) |
| 26 | return 0; |
| 27 | return wildmatch(tok, host); |
| 28 | } |
| 29 | |
| 30 | static int match_binary(char *b1, char *b2, char *mask, int addrlen) |
| 31 | { |
| 32 | int i; |
| 33 | |
| 34 | for (i = 0; i < addrlen; i++) { |
| 35 | if ((b1[i] ^ b2[i]) & mask[i]) |
| 36 | return 0; |
| 37 | } |
| 38 | |
| 39 | return 1; |
| 40 | } |
| 41 | |
| 42 | static void make_mask(char *mask, int plen, int addrlen) |
| 43 | { |
| 44 | int w, b; |
| 45 | |
| 46 | w = plen >> 3; |
| 47 | b = plen & 0x7; |
| 48 | |
| 49 | if (w) |
| 50 | memset(mask, 0xff, w); |
| 51 | if (w < addrlen) |
| 52 | mask[w] = 0xff & (0xff<<(8-b)); |
| 53 | if (w+1 < addrlen) |
| 54 | memset(mask+w+1, 0, addrlen-w-1); |
| 55 | |
| 56 | return; |
| 57 | } |
| 58 | |
| 59 | static int match_address(char *addr, char *tok) |
| 60 | { |
| 61 | char *p; |
| 62 | struct addrinfo hints, *resa, *rest; |
| 63 | int gai; |
| 64 | int ret = 0; |
| 65 | int addrlen = 0; |
| 66 | #ifdef HAVE_STRTOL |
| 67 | long int bits; |
| 68 | #else |
| 69 | int bits; |
| 70 | #endif |
| 71 | char mask[16]; |
| 72 | char *a = NULL, *t = NULL; |
| 73 | unsigned int len; |
| 74 | |
| 75 | if (!addr || !*addr) |
| 76 | return 0; |
| 77 | |
| 78 | p = strchr(tok,'/'); |
| 79 | if (p) { |
| 80 | *p = '\0'; |
| 81 | len = p - tok; |
| 82 | } else |
| 83 | len = strlen(tok); |
| 84 | |
| 85 | /* Fail quietly if tok is a hostname (not an address) */ |
| 86 | if (strspn(tok, ".0123456789") != len |
| 87 | #ifdef INET6 |
| 88 | && strchr(tok, ':') == NULL |
| 89 | #endif |
| 90 | ) { |
| 91 | if (p) |
| 92 | *p = '/'; |
| 93 | return 0; |
| 94 | } |
| 95 | |
| 96 | memset(&hints, 0, sizeof(hints)); |
| 97 | hints.ai_family = PF_UNSPEC; |
| 98 | hints.ai_socktype = SOCK_STREAM; |
| 99 | #ifdef AI_NUMERICHOST |
| 100 | hints.ai_flags = AI_NUMERICHOST; |
| 101 | #endif |
| 102 | |
| 103 | if (getaddrinfo(addr, NULL, &hints, &resa) != 0) { |
| 104 | if (p) |
| 105 | *p = '/'; |
| 106 | return 0; |
| 107 | } |
| 108 | |
| 109 | gai = getaddrinfo(tok, NULL, &hints, &rest); |
| 110 | if (p) |
| 111 | *p++ = '/'; |
| 112 | if (gai != 0) { |
| 113 | rprintf(FLOG, "error matching address %s: %s\n", |
| 114 | tok, gai_strerror(gai)); |
| 115 | freeaddrinfo(resa); |
| 116 | return 0; |
| 117 | } |
| 118 | |
| 119 | if (rest->ai_family != resa->ai_family) { |
| 120 | ret = 0; |
| 121 | goto out; |
| 122 | } |
| 123 | |
| 124 | switch(resa->ai_family) { |
| 125 | case PF_INET: |
| 126 | a = (char *)&((struct sockaddr_in *)resa->ai_addr)->sin_addr; |
| 127 | t = (char *)&((struct sockaddr_in *)rest->ai_addr)->sin_addr; |
| 128 | addrlen = 4; |
| 129 | |
| 130 | break; |
| 131 | |
| 132 | #ifdef INET6 |
| 133 | case PF_INET6: |
| 134 | { |
| 135 | struct sockaddr_in6 *sin6a, *sin6t; |
| 136 | |
| 137 | sin6a = (struct sockaddr_in6 *)resa->ai_addr; |
| 138 | sin6t = (struct sockaddr_in6 *)rest->ai_addr; |
| 139 | |
| 140 | a = (char *)&sin6a->sin6_addr; |
| 141 | t = (char *)&sin6t->sin6_addr; |
| 142 | |
| 143 | addrlen = 16; |
| 144 | |
| 145 | #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID |
| 146 | if (sin6t->sin6_scope_id && |
| 147 | sin6a->sin6_scope_id != sin6t->sin6_scope_id) { |
| 148 | ret = 0; |
| 149 | goto out; |
| 150 | } |
| 151 | #endif |
| 152 | |
| 153 | break; |
| 154 | } |
| 155 | #endif |
| 156 | default: |
| 157 | rprintf(FLOG, "unknown family %u\n", rest->ai_family); |
| 158 | ret = 0; |
| 159 | goto out; |
| 160 | } |
| 161 | |
| 162 | bits = -1; |
| 163 | if (p) { |
| 164 | if (inet_pton(resa->ai_addr->sa_family, p, mask) <= 0) { |
| 165 | #ifdef HAVE_STRTOL |
| 166 | char *ep = NULL; |
| 167 | #else |
| 168 | unsigned char *pp; |
| 169 | #endif |
| 170 | |
| 171 | #ifdef HAVE_STRTOL |
| 172 | bits = strtol(p, &ep, 10); |
| 173 | if (!*p || *ep) { |
| 174 | rprintf(FLOG, "malformed mask in %s\n", tok); |
| 175 | ret = 0; |
| 176 | goto out; |
| 177 | } |
| 178 | #else |
| 179 | for (pp = (unsigned char *)p; *pp; pp++) { |
| 180 | if (!isascii(*pp) || !isdigit(*pp)) { |
| 181 | rprintf(FLOG, "malformed mask in %s\n", tok); |
| 182 | ret = 0; |
| 183 | goto out; |
| 184 | } |
| 185 | } |
| 186 | bits = atoi(p); |
| 187 | #endif |
| 188 | if (bits == 0) { |
| 189 | ret = 1; |
| 190 | goto out; |
| 191 | } |
| 192 | if (bits < 0 || bits > (addrlen << 3)) { |
| 193 | rprintf(FLOG, "malformed mask in %s\n", tok); |
| 194 | ret = 0; |
| 195 | goto out; |
| 196 | } |
| 197 | } |
| 198 | } else { |
| 199 | bits = 128; |
| 200 | } |
| 201 | |
| 202 | if (bits >= 0) |
| 203 | make_mask(mask, bits, addrlen); |
| 204 | |
| 205 | ret = match_binary(a, t, mask, addrlen); |
| 206 | |
| 207 | out: |
| 208 | freeaddrinfo(resa); |
| 209 | freeaddrinfo(rest); |
| 210 | return ret; |
| 211 | } |
| 212 | |
| 213 | static int access_match(char *list, char *addr, char *host) |
| 214 | { |
| 215 | char *tok; |
| 216 | char *list2 = strdup(list); |
| 217 | |
| 218 | if (!list2) |
| 219 | out_of_memory("access_match"); |
| 220 | |
| 221 | strlower(list2); |
| 222 | if (host) |
| 223 | strlower(host); |
| 224 | |
| 225 | for (tok = strtok(list2, " ,\t"); tok; tok = strtok(NULL, " ,\t")) { |
| 226 | if (match_hostname(host, tok) || match_address(addr, tok)) { |
| 227 | free(list2); |
| 228 | return 1; |
| 229 | } |
| 230 | } |
| 231 | |
| 232 | free(list2); |
| 233 | return 0; |
| 234 | } |
| 235 | |
| 236 | int allow_access(char *addr, char *host, char *allow_list, char *deny_list) |
| 237 | { |
| 238 | if (allow_list && !*allow_list) |
| 239 | allow_list = NULL; |
| 240 | if (deny_list && !*deny_list) |
| 241 | deny_list = NULL; |
| 242 | |
| 243 | /* If we match an allow-list item, we always allow access. */ |
| 244 | if (allow_list) { |
| 245 | if (access_match(allow_list, addr, host)) |
| 246 | return 1; |
| 247 | /* For an allow-list w/o a deny-list, disallow non-matches. */ |
| 248 | if (!deny_list) |
| 249 | return 0; |
| 250 | } |
| 251 | |
| 252 | /* If we match a deny-list item (and got past any allow-list |
| 253 | * items), we always disallow access. */ |
| 254 | if (deny_list && access_match(deny_list, addr, host)) |
| 255 | return 0; |
| 256 | |
| 257 | /* Allow all other access. */ |
| 258 | return 1; |
| 259 | } |