src/blacklist.c

   1 /*
   2  * charybdis: A slightly useful ircd.
   3  * blacklist.c: Manages DNS blacklist entries and lookups
   4  *
   5  * Copyright (C) 2006-2011 charybdis development team
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions are
   9  * met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright notice,
  12  *    this list of conditions and the following disclaimer.
  13  *
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * 3. The name of the author may not be used to endorse or promote products
  19  *    derived from this software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  23  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
  25  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  26  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  27  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  29  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  30  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  31  * POSSIBILITY OF SUCH DAMAGE.
  32  *
  33  */
  34
  35 #include "stdinc.h"
  36 #include "client.h"
  37 #include "res.h"
  38 #include "numeric.h"
  39 #include "reject.h"
  40 #include "s_conf.h"
  41 #include "s_user.h"
  42 #include "blacklist.h"
  43 #include "send.h"
  44
  45 rb_dlink_list blacklist_list = { NULL, NULL, 0 };
  46
  47 /* private interfaces */
  48 static struct Blacklist *find_blacklist(char *name)
  49 {
  50         rb_dlink_node *nptr;
  51
  52         RB_DLINK_FOREACH(nptr, blacklist_list.head)
  53         {
  54                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
  55
  56                 if (!irccmp(blptr->host, name))
  57                         return blptr;
  58         }
  59
  60         return NULL;
  61 }
  62
  63 static inline int blacklist_check_reply(struct BlacklistClient *blcptr, struct rb_sockaddr_storage *addr)
  64 {
  65         struct Blacklist *blptr = blcptr->blacklist;
  66         char ipaddr[HOSTIPLEN];
  67         char *lastoctet;
  68         rb_dlink_node *ptr;
  69
  70         /* XXX the below two checks might want to change at some point
  71          * e.g. if IPv6 blacklists don't use 127.x.y.z or A records anymore
  72          * --Elizabeth
  73          */
  74         if (addr->ss_family != AF_INET ||
  75                         memcmp(&((struct sockaddr_in *)addr)->sin_addr, "\177", 1))
  76                 goto blwarn;
  77
  78         /* No filters and entry found - thus positive match */
  79         if (!rb_dlink_list_length(&blptr->filters))
  80                 return 1;
  81
  82         rb_inet_ntop_sock((struct sockaddr *)addr, ipaddr, sizeof(ipaddr));
  83
  84         /* Below will prolly have to change too if the above changes */
  85         if ((lastoctet = strrchr(ipaddr, '.')) == NULL || *(++lastoctet) == '\0')
  86                 goto blwarn;
  87
  88         RB_DLINK_FOREACH(ptr, blcptr->blacklist->filters.head)
  89         {
  90                 struct BlacklistFilter *filter = ptr->data;
  91                 char *cmpstr;
  92
  93                 if (filter->type == BLACKLIST_FILTER_ALL)
  94                         cmpstr = ipaddr;
  95                 else if (filter->type == BLACKLIST_FILTER_LAST)
  96                         cmpstr = lastoctet;
  97                 else
  98                 {
  99                         sendto_realops_snomask(SNO_GENERAL, L_ALL,
 100                                         "blacklist_check_reply(): Unknown filtertype (BUG!)");
 101                         continue;
 102                 }
 103
 104                 if (strcmp(cmpstr, filter->filterstr) == 0)
 105                         /* Match! */
 106                         return 1;
 107         }
 108
 109         return 0;
 110 blwarn:
 111         if (blcptr->blacklist->lastwarning + 3600 < rb_current_time())
 112         {
 113                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 114                                 "Garbage reply from blacklist %s",
 115                                 blcptr->blacklist->host);
 116                 blcptr->blacklist->lastwarning = rb_current_time();
 117         }
 118         return 0;
 119 }
 120
 121 static void blacklist_dns_callback(void *vptr, struct DNSReply *reply)
 122 {
 123         struct BlacklistClient *blcptr = (struct BlacklistClient *) vptr;
 124         int listed = 0;
 125
 126         if (blcptr == NULL || blcptr->client_p == NULL)
 127                 return;
 128
 129         if (blcptr->client_p->preClient == NULL)
 130         {
 131                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 132                                 "blacklist_dns_callback(): blcptr->client_p->preClient (%s) is NULL", get_client_name(blcptr->client_p, HIDE_IP));
 133                 rb_free(blcptr);
 134                 return;
 135         }
 136
 137         if (reply != NULL)
 138         {
 139                 if (blacklist_check_reply(blcptr, &reply->addr))
 140                         listed = TRUE;
 141         }
 142
 143         /* they have a blacklist entry for this client */
 144         if (listed && blcptr->client_p->preClient->dnsbl_listed == NULL)
 145         {
 146                 blcptr->client_p->preClient->dnsbl_listed = blcptr->blacklist;
 147                 /* reference to blacklist moves from blcptr to client_p->preClient... */
 148         }
 149         else
 150                 unref_blacklist(blcptr->blacklist);
 151
 152         rb_dlinkDelete(&blcptr->node, &blcptr->client_p->preClient->dnsbl_queries);
 153
 154         /* yes, it can probably happen... */
 155         if (rb_dlink_list_length(&blcptr->client_p->preClient->dnsbl_queries) == 0 && blcptr->client_p->flags & FLAGS_SENTUSER && !EmptyString(blcptr->client_p->name))
 156                 register_local_user(blcptr->client_p, blcptr->client_p);
 157
 158         rb_free(blcptr);
 159 }
 160
 161 static void initiate_blacklist_dnsquery(struct Blacklist *blptr, struct Client *client_p)
 162 {
 163         struct BlacklistClient *blcptr = rb_malloc(sizeof(struct BlacklistClient));
 164         char buf[IRCD_RES_HOSTLEN + 1];
 165         uint8_t *ip;
 166
 167         blcptr->blacklist = blptr;
 168         blcptr->client_p = client_p;
 169
 170         blcptr->dns_query.ptr = blcptr;
 171         blcptr->dns_query.callback = blacklist_dns_callback;
 172
 173         if ((client_p->localClient->ip.ss_family == AF_INET) && blptr->ipv4)
 174         {
 175                 ip = (uint8_t *)&((struct sockaddr_in *)&client_p->localClient->ip)->sin_addr.s_addr;
 176
 177                 /* becomes 2.0.0.127.torbl.ahbl.org or whatever */
 178                 rb_snprintf(buf, sizeof buf, "%d.%d.%d.%d.%s",
 179                             (unsigned int) ip[3],
 180                             (unsigned int) ip[2],
 181                             (unsigned int) ip[1],
 182                             (unsigned int) ip[0],
 183                             blptr->host);
 184         }
 185         /* IPv6 is supported now. --Elizabeth */
 186         else if ((client_p->localClient->ip.ss_family == AF_INET6) && blptr->ipv6)
 187         {
 188                 /* Breaks it into ip[0] = 0x00, ip[1] = 0x00... ip[16] = 0x01 for localhost
 189                  * I wish there was a uint4_t for C, this would make the below cleaner, but... */
 190                 ip = (uint8_t *)&((struct sockaddr_in6 *)&client_p->localClient->ip)->sin6_addr.s6_addr;
 191                 char *bufptr = buf;
 192                 int i;
 193
 194                 /* The below will give us something like
 195                  * 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.foobl.invalid
 196                  */
 197
 198                 /* Going backwards */
 199                 for (i = 15; i >= 0; i--)
 200                 {
 201                         /* Get upper and lower nibbles (yes this works fine on
 202                          * both big and little endian) */
 203                         uint8_t hi = (ip[i] >> 4) & 0x0F;
 204                         uint8_t lo = ip[i] & 0x0F;
 205
 206                         /* One part... (why 5? rb_snprintf adds \0) */
 207                         rb_snprintf(bufptr, 5, "%1x.%1x.",
 208                                     (unsigned int) lo, /* Remember, backwards */
 209                                     (unsigned int) hi);
 210
 211                         /* Lurch forward to next position */
 212                         bufptr += 4;
 213                 }
 214
 215                 /* Tack host on */
 216                 strcpy(bufptr, blptr->host);
 217         }
 218         /* This shouldn't happen... */
 219         else
 220                 return;
 221
 222         gethost_byname_type(buf, &blcptr->dns_query, T_A);
 223
 224         rb_dlinkAdd(blcptr, &blcptr->node, &client_p->preClient->dnsbl_queries);
 225         blptr->refcount++;
 226 }
 227
 228 /* public interfaces */
 229 struct Blacklist *new_blacklist(char *name, char *reject_reason, int ipv4, int ipv6, rb_dlink_list *filters)
 230 {
 231         struct Blacklist *blptr;
 232
 233         if (name == NULL || reject_reason == NULL)
 234                 return NULL;
 235
 236         blptr = find_blacklist(name);
 237         if (blptr == NULL)
 238         {
 239                 blptr = rb_malloc(sizeof(struct Blacklist));
 240                 rb_dlinkAddAlloc(blptr, &blacklist_list);
 241         }
 242         else
 243                 blptr->status &= ~CONF_ILLEGAL;
 244
 245         rb_strlcpy(blptr->host, name, IRCD_RES_HOSTLEN + 1);
 246         rb_strlcpy(blptr->reject_reason, reject_reason, IRCD_BUFSIZE);
 247         blptr->ipv4 = ipv4;
 248         blptr->ipv6 = ipv6;
 249
 250         rb_dlinkMoveList(filters, &blptr->filters);
 251
 252         blptr->lastwarning = 0;
 253
 254         return blptr;
 255 }
 256
 257 void unref_blacklist(struct Blacklist *blptr)
 258 {
 259         rb_dlink_node *ptr, *next_ptr;
 260
 261         blptr->refcount--;
 262         if (blptr->status & CONF_ILLEGAL && blptr->refcount <= 0)
 263         {
 264                 RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blptr->filters.head)
 265                 {
 266                         rb_dlinkDelete(ptr, &blptr->filters);
 267                         rb_free(ptr);
 268                 }
 269
 270                 rb_dlinkFindDestroy(blptr, &blacklist_list);
 271                 rb_free(blptr);
 272         }
 273 }
 274
 275 void lookup_blacklists(struct Client *client_p)
 276 {
 277         rb_dlink_node *nptr;
 278
 279         RB_DLINK_FOREACH(nptr, blacklist_list.head)
 280         {
 281                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
 282
 283                 if (!(blptr->status & CONF_ILLEGAL))
 284                         initiate_blacklist_dnsquery(blptr, client_p);
 285         }
 286 }
 287
 288 void abort_blacklist_queries(struct Client *client_p)
 289 {
 290         rb_dlink_node *ptr, *next_ptr;
 291         struct BlacklistClient *blcptr;
 292
 293         if (client_p->preClient == NULL)
 294                 return;
 295         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, client_p->preClient->dnsbl_queries.head)
 296         {
 297                 blcptr = ptr->data;
 298                 rb_dlinkDelete(&blcptr->node, &client_p->preClient->dnsbl_queries);
 299                 unref_blacklist(blcptr->blacklist);
 300                 delete_resolver_queries(&blcptr->dns_query);
 301                 rb_free(blcptr);
 302         }
 303 }
 304
 305 void destroy_blacklists(void)
 306 {
 307         rb_dlink_node *ptr, *next_ptr;
 308         struct Blacklist *blptr;
 309
 310         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blacklist_list.head)
 311         {
 312                 blptr = ptr->data;
 313                 blptr->hits = 0; /* keep it simple and consistent */
 314                 if (blptr->refcount > 0)
 315                         blptr->status |= CONF_ILLEGAL;
 316                 else
 317                 {
 318                         rb_free(ptr->data);
 319                         rb_dlinkDestroy(ptr, &blacklist_list);
 320                 }
 321         }
 322 }