ircd/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 "dns.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, const char *ipaddr)
  64 {
  65         struct Blacklist *blptr = blcptr->blacklist;
  66         const char *lastoctet;
  67         rb_dlink_node *ptr;
  68
  69         /* No filters and entry found - thus positive match */
  70         if (!rb_dlink_list_length(&blptr->filters))
  71                 return 1;
  72
  73         /* Below will prolly have to change too if the above changes */
  74         if ((lastoctet = strrchr(ipaddr, '.')) == NULL || *(++lastoctet) == '\0')
  75                 goto blwarn;
  76
  77         RB_DLINK_FOREACH(ptr, blcptr->blacklist->filters.head)
  78         {
  79                 struct BlacklistFilter *filter = ptr->data;
  80                 const char *cmpstr;
  81
  82                 if (filter->type == BLACKLIST_FILTER_ALL)
  83                         cmpstr = ipaddr;
  84                 else if (filter->type == BLACKLIST_FILTER_LAST)
  85                         cmpstr = lastoctet;
  86                 else
  87                 {
  88                         sendto_realops_snomask(SNO_GENERAL, L_ALL,
  89                                         "blacklist_check_reply(): Unknown filtertype (BUG!)");
  90                         continue;
  91                 }
  92
  93                 if (strcmp(cmpstr, filter->filterstr) == 0)
  94                         /* Match! */
  95                         return 1;
  96         }
  97
  98         return 0;
  99 blwarn:
 100         if (blcptr->blacklist->lastwarning + 3600 < rb_current_time())
 101         {
 102                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 103                                 "Garbage reply from blacklist %s",
 104                                 blcptr->blacklist->host);
 105                 blcptr->blacklist->lastwarning = rb_current_time();
 106         }
 107         return 0;
 108 }
 109
 110 static void blacklist_dns_callback(const char *result, int status, int aftype, void *vptr)
 111 {
 112         struct BlacklistClient *blcptr = (struct BlacklistClient *) vptr;
 113         int listed = 0;
 114
 115         if (blcptr == NULL || blcptr->client_p == NULL)
 116                 return;
 117
 118         if (blcptr->client_p->preClient == NULL)
 119         {
 120                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 121                                 "blacklist_dns_callback(): blcptr->client_p->preClient (%s) is NULL", get_client_name(blcptr->client_p, HIDE_IP));
 122                 rb_free(blcptr);
 123                 return;
 124         }
 125
 126         if (result != NULL && status)
 127         {
 128                 if (blacklist_check_reply(blcptr, result))
 129                         listed = TRUE;
 130         }
 131
 132         /* they have a blacklist entry for this client */
 133         if (listed && blcptr->client_p->preClient->dnsbl_listed == NULL)
 134         {
 135                 blcptr->client_p->preClient->dnsbl_listed = blcptr->blacklist;
 136                 /* reference to blacklist moves from blcptr to client_p->preClient... */
 137         }
 138         else
 139                 unref_blacklist(blcptr->blacklist);
 140
 141         rb_dlinkDelete(&blcptr->node, &blcptr->client_p->preClient->dnsbl_queries);
 142
 143         /* yes, it can probably happen... */
 144         if (rb_dlink_list_length(&blcptr->client_p->preClient->dnsbl_queries) == 0 && blcptr->client_p->flags & FLAGS_SENTUSER && !EmptyString(blcptr->client_p->name))
 145                 register_local_user(blcptr->client_p, blcptr->client_p);
 146
 147         rb_free(blcptr);
 148 }
 149
 150 static void initiate_blacklist_dnsquery(struct Blacklist *blptr, struct Client *client_p)
 151 {
 152         struct BlacklistClient *blcptr = rb_malloc(sizeof(struct BlacklistClient));
 153         char buf[IRCD_RES_HOSTLEN + 1];
 154         uint8_t *ip;
 155
 156         blcptr->blacklist = blptr;
 157         blcptr->client_p = client_p;
 158
 159         if ((client_p->localClient->ip.ss_family == AF_INET) && blptr->ipv4)
 160         {
 161                 ip = (uint8_t *)&((struct sockaddr_in *)&client_p->localClient->ip)->sin_addr.s_addr;
 162
 163                 /* becomes 2.0.0.127.torbl.ahbl.org or whatever */
 164                 rb_snprintf(buf, sizeof buf, "%d.%d.%d.%d.%s",
 165                             (unsigned int) ip[3],
 166                             (unsigned int) ip[2],
 167                             (unsigned int) ip[1],
 168                             (unsigned int) ip[0],
 169                             blptr->host);
 170         }
 171         /* IPv6 is supported now. --Elizabeth */
 172         else if ((client_p->localClient->ip.ss_family == AF_INET6) && blptr->ipv6)
 173         {
 174                 /* Breaks it into ip[0] = 0x00, ip[1] = 0x00... ip[16] = 0x01 for localhost
 175                  * I wish there was a uint4_t for C, this would make the below cleaner, but... */
 176                 ip = (uint8_t *)&((struct sockaddr_in6 *)&client_p->localClient->ip)->sin6_addr.s6_addr;
 177                 char *bufptr = buf;
 178                 int i;
 179
 180                 /* The below will give us something like
 181                  * 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
 182                  */
 183
 184                 /* Going backwards */
 185                 for (i = 15; i >= 0; i--)
 186                 {
 187                         /* Get upper and lower nibbles (yes this works fine on
 188                          * both big and little endian) */
 189                         uint8_t hi = (ip[i] >> 4) & 0x0F;
 190                         uint8_t lo = ip[i] & 0x0F;
 191
 192                         /* One part... (why 5? rb_snprintf adds \0) */
 193                         rb_snprintf(bufptr, 5, "%1x.%1x.",
 194                                     (unsigned int) lo, /* Remember, backwards */
 195                                     (unsigned int) hi);
 196
 197                         /* Lurch forward to next position */
 198                         bufptr += 4;
 199                 }
 200
 201                 /* Tack host on */
 202                 strcpy(bufptr, blptr->host);
 203         }
 204         /* This shouldn't happen... */
 205         else
 206                 return;
 207
 208         blcptr->dns_id = lookup_hostname(buf, AF_INET, blacklist_dns_callback, blcptr);
 209
 210         rb_dlinkAdd(blcptr, &blcptr->node, &client_p->preClient->dnsbl_queries);
 211         blptr->refcount++;
 212 }
 213
 214 /* public interfaces */
 215 struct Blacklist *new_blacklist(char *name, char *reject_reason, int ipv4, int ipv6, rb_dlink_list *filters)
 216 {
 217         struct Blacklist *blptr;
 218
 219         if (name == NULL || reject_reason == NULL)
 220                 return NULL;
 221
 222         blptr = find_blacklist(name);
 223         if (blptr == NULL)
 224         {
 225                 blptr = rb_malloc(sizeof(struct Blacklist));
 226                 rb_dlinkAddAlloc(blptr, &blacklist_list);
 227         }
 228         else
 229                 blptr->status &= ~CONF_ILLEGAL;
 230
 231         rb_strlcpy(blptr->host, name, IRCD_RES_HOSTLEN + 1);
 232         rb_strlcpy(blptr->reject_reason, reject_reason, IRCD_BUFSIZE);
 233         blptr->ipv4 = ipv4;
 234         blptr->ipv6 = ipv6;
 235
 236         rb_dlinkMoveList(filters, &blptr->filters);
 237
 238         blptr->lastwarning = 0;
 239
 240         return blptr;
 241 }
 242
 243 void unref_blacklist(struct Blacklist *blptr)
 244 {
 245         rb_dlink_node *ptr, *next_ptr;
 246
 247         blptr->refcount--;
 248         if (blptr->status & CONF_ILLEGAL && blptr->refcount <= 0)
 249         {
 250                 RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blptr->filters.head)
 251                 {
 252                         rb_dlinkDelete(ptr, &blptr->filters);
 253                         rb_free(ptr);
 254                 }
 255
 256                 rb_dlinkFindDestroy(blptr, &blacklist_list);
 257                 rb_free(blptr);
 258         }
 259 }
 260
 261 void lookup_blacklists(struct Client *client_p)
 262 {
 263         rb_dlink_node *nptr;
 264
 265         RB_DLINK_FOREACH(nptr, blacklist_list.head)
 266         {
 267                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
 268
 269                 if (!(blptr->status & CONF_ILLEGAL))
 270                         initiate_blacklist_dnsquery(blptr, client_p);
 271         }
 272 }
 273
 274 void abort_blacklist_queries(struct Client *client_p)
 275 {
 276         rb_dlink_node *ptr, *next_ptr;
 277         struct BlacklistClient *blcptr;
 278
 279         if (client_p->preClient == NULL)
 280                 return;
 281         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, client_p->preClient->dnsbl_queries.head)
 282         {
 283                 blcptr = ptr->data;
 284                 rb_dlinkDelete(&blcptr->node, &client_p->preClient->dnsbl_queries);
 285                 unref_blacklist(blcptr->blacklist);
 286                 cancel_lookup(blcptr->dns_id);
 287                 rb_free(blcptr);
 288         }
 289 }
 290
 291 void destroy_blacklists(void)
 292 {
 293         rb_dlink_node *ptr, *next_ptr;
 294         struct Blacklist *blptr;
 295
 296         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blacklist_list.head)
 297         {
 298                 blptr = ptr->data;
 299                 blptr->hits = 0; /* keep it simple and consistent */
 300                 if (blptr->refcount > 0)
 301                         blptr->status |= CONF_ILLEGAL;
 302                 else
 303                 {
 304                         rb_free(ptr->data);
 305                         rb_dlinkDestroy(ptr, &blacklist_list);
 306                 }
 307         }
 308 }