access.c

   1 /*
   2    Copyright (C) Andrew Tridgell 1998
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17 */
  18
  19 /*
  20   hosts allow/deny code for rsync
  21
  22   */
  23
  24 #include "rsync.h"
  25
  26
  27 static int match_hostname(char *host, char *tok)
  28 {
  29         if (!host || !*host) return 0;
  30         return wildmatch(tok, host);
  31 }
  32
  33 static int match_binary(char *b1, char *b2, char *mask, int addrlen)
  34 {
  35         int i;
  36
  37         for (i=0; i<addrlen; i++) {
  38                 if ((b1[i]^b2[i])&mask[i]) {
  39                         return 0;
  40                 }
  41         }
  42
  43         return 1;
  44 }
  45
  46 static void make_mask(char *mask, int plen, int addrlen) {
  47         int w, b;
  48
  49         w = plen >> 3;
  50         b = plen & 0x7;
  51
  52         if (w)
  53                 memset(mask, 0xff, w);
  54         if (w < addrlen)
  55                 mask[w] = 0xff & (0xff<<(8-b));
  56         if (w+1 < addrlen)
  57                 memset(mask+w+1, 0, addrlen-w-1);
  58
  59         return;
  60 }
  61
  62 static int match_address(char *addr, char *tok)
  63 {
  64         char *p;
  65         struct addrinfo hints, *resa, *rest;
  66         int gai;
  67         int ret = 0;
  68         int addrlen = 0;
  69 #ifdef HAVE_STRTOL
  70         long int bits;
  71 #else
  72         int bits;
  73 #endif
  74         char mask[16];
  75         char *a = NULL, *t = NULL;
  76         unsigned int len;
  77
  78         if (!addr || !*addr) return 0;
  79
  80         p = strchr(tok,'/');
  81         if (p) {
  82                 *p = '\0';
  83                 len = p - tok;
  84         }
  85         else
  86                 len = strlen(tok);
  87
  88         /* Fail quietly if tok is a hostname (not an address) */
  89         if (strspn(tok, ".0123456789") != len
  90 #ifdef INET6
  91          && !strchr(tok, ':')
  92 #endif
  93                 ) return 0;
  94
  95         memset(&hints, 0, sizeof(hints));
  96         hints.ai_family = PF_UNSPEC;
  97         hints.ai_socktype = SOCK_STREAM;
  98 #ifdef AI_NUMERICHOST
  99         hints.ai_flags = AI_NUMERICHOST;
 100 #endif
 101
 102         gai = getaddrinfo(addr, NULL, &hints, &resa);
 103         if (gai) return 0;
 104
 105         gai = getaddrinfo(tok, NULL, &hints, &rest);
 106         if (p)
 107                 *p++ = '/';
 108         if (gai) {
 109                 rprintf(FERROR,
 110                         "error matching address %s: %s\n",
 111                         tok,
 112                         gai_strerror(gai));
 113                 freeaddrinfo(resa);
 114                 return 0;
 115         }
 116
 117         if (rest->ai_family != resa->ai_family) {
 118                 ret = 0;
 119                 goto out;
 120         }
 121
 122         switch(resa->ai_family) {
 123         case PF_INET:
 124                 a = (char *)&((struct sockaddr_in *)resa->ai_addr)->sin_addr;
 125                 t = (char *)&((struct sockaddr_in *)rest->ai_addr)->sin_addr;
 126                 addrlen = 4;
 127
 128                 break;
 129
 130 #ifdef INET6
 131         case PF_INET6:
 132             {
 133                 struct sockaddr_in6 *sin6a, *sin6t;
 134
 135                 sin6a = (struct sockaddr_in6 *)resa->ai_addr;
 136                 sin6t = (struct sockaddr_in6 *)rest->ai_addr;
 137
 138                 a = (char *)&sin6a->sin6_addr;
 139                 t = (char *)&sin6t->sin6_addr;
 140
 141                 addrlen = 16;
 142
 143 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
 144                 if (sin6t->sin6_scope_id &&
 145                     sin6a->sin6_scope_id != sin6t->sin6_scope_id) {
 146                         ret = 0;
 147                         goto out;
 148                 }
 149 #endif
 150
 151                 break;
 152             }
 153 #endif
 154         default:
 155             rprintf(FERROR,"unknown family %u\n", rest->ai_family);
 156             ret = 0;
 157             goto out;
 158         }
 159
 160         bits = -1;
 161         if (p) {
 162                 if (inet_pton(resa->ai_addr->sa_family, p, mask) <= 0) {
 163 #ifdef HAVE_STRTOL
 164                         char *ep = NULL;
 165 #else
 166                         unsigned char *pp;
 167 #endif
 168
 169 #ifdef HAVE_STRTOL
 170                         bits = strtol(p, &ep, 10);
 171                         if (!*p || *ep) {
 172                                 rprintf(FERROR,"malformed mask in %s\n", tok);
 173                                 ret = 0;
 174                                 goto out;
 175                         }
 176 #else
 177                         for (pp = (unsigned char *)p; *pp; pp++) {
 178                                 if (!isascii(*pp) || !isdigit(*pp)) {
 179                                         rprintf(FERROR,"malformed mask in %s\n", tok);
 180                                         ret = 0;
 181                                         goto out;
 182                                 }
 183                         }
 184                         bits = atoi(p);
 185 #endif
 186                         if (bits == 0) {
 187                                 ret = 1;
 188                                 goto out;
 189                         }
 190                         if (bits < 0 || bits > (addrlen << 3)) {
 191                                 rprintf(FERROR,"malformed mask in %s\n", tok);
 192                                 ret = 0;
 193                                 goto out;
 194                         }
 195                 }
 196         } else {
 197                 bits = 128;
 198         }
 199
 200         if (bits >= 0)
 201                 make_mask(mask, bits, addrlen);
 202
 203         ret = match_binary(a, t, mask, addrlen);
 204
 205 out:
 206         freeaddrinfo(resa);
 207         freeaddrinfo(rest);
 208         return ret;
 209 }
 210
 211 static int access_match(char *list, char *addr, char *host)
 212 {
 213         char *tok;
 214         char *list2 = strdup(list);
 215
 216         if (!list2) out_of_memory("access_match");
 217
 218         strlower(list2);
 219         if (host) strlower(host);
 220
 221         for (tok=strtok(list2," ,\t"); tok; tok=strtok(NULL," ,\t")) {
 222                 if (match_hostname(host, tok) || match_address(addr, tok)) {
 223                         free(list2);
 224                         return 1;
 225                 }
 226         }
 227
 228         free(list2);
 229         return 0;
 230 }
 231
 232 int allow_access(char *addr, char *host, char *allow_list, char *deny_list)
 233 {
 234         /* if theres no deny list and no allow list then allow access */
 235         if ((!deny_list || !*deny_list) && (!allow_list || !*allow_list))
 236                 return 1;
 237
 238         /* if there is an allow list but no deny list then allow only hosts
 239            on the allow list */
 240         if (!deny_list || !*deny_list)
 241                 return(access_match(allow_list, addr, host));
 242
 243         /* if theres a deny list but no allow list then allow
 244            all hosts not on the deny list */
 245         if (!allow_list || !*allow_list)
 246                 return(!access_match(deny_list,addr,host));
 247
 248         /* if there are both type of list then allow all hosts on the
 249            allow list */
 250         if (access_match(allow_list,addr,host))
 251                 return 1;
 252
 253         /* if there are both type of list and it's not on the allow then
 254            allow it if its not on the deny */
 255         if (access_match(deny_list,addr,host))
 256                 return 0;
 257
 258         return 1;
 259 }