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 #include "stdinc.h"
  35 #include "client.h"
  36 #include "dns.h"
  37 #include "numeric.h"
  38 #include "reject.h"
  39 #include "s_conf.h"
  40 #include "s_user.h"
  41 #include "blacklist.h"
  42 #include "send.h"
  43
  44 rb_dlink_list blacklist_list = { NULL, NULL, 0 };
  45
  46 /* private interfaces */
  47 static struct Blacklist *find_blacklist(char *name)
  48 {
  49         rb_dlink_node *nptr;
  50
  51         RB_DLINK_FOREACH(nptr, blacklist_list.head)
  52         {
  53                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
  54
  55                 if (!irccmp(blptr->host, name))
  56                         return blptr;
  57         }
  58
  59         return NULL;
  60 }
  61
  62 static inline int blacklist_check_reply(struct BlacklistClient *blcptr, const char *ipaddr)
  63 {
  64         struct Blacklist *blptr = blcptr->blacklist;
  65         const char *lastoctet;
  66         rb_dlink_node *ptr;
  67
  68         /* No filters and entry found - thus positive match */
  69         if (!rb_dlink_list_length(&blptr->filters))
  70                 return 1;
  71
  72         /* Below will prolly have to change too if the above changes */
  73         if ((lastoctet = strrchr(ipaddr, '.')) == NULL || *(++lastoctet) == '\0')
  74                 goto blwarn;
  75
  76         RB_DLINK_FOREACH(ptr, blcptr->blacklist->filters.head)
  77         {
  78                 struct BlacklistFilter *filter = ptr->data;
  79                 const char *cmpstr;
  80
  81                 if (filter->type == BLACKLIST_FILTER_ALL)
  82                         cmpstr = ipaddr;
  83                 else if (filter->type == BLACKLIST_FILTER_LAST)
  84                         cmpstr = lastoctet;
  85                 else
  86                 {
  87                         sendto_realops_snomask(SNO_GENERAL, L_ALL,
  88                                         "blacklist_check_reply(): Unknown filtertype (BUG!)");
  89                         continue;
  90                 }
  91
  92                 if (strcmp(cmpstr, filter->filterstr) == 0)
  93                         /* Match! */
  94                         return 1;
  95         }
  96
  97         return 0;
  98 blwarn:
  99         if (blcptr->blacklist->lastwarning + 3600 < rb_current_time())
 100         {
 101                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 102                                 "Garbage reply from blacklist %s",
 103                                 blcptr->blacklist->host);
 104                 blcptr->blacklist->lastwarning = rb_current_time();
 105         }
 106         return 0;
 107 }
 108
 109 static void blacklist_dns_callback(const char *result, int status, int aftype, void *vptr)
 110 {
 111         struct BlacklistClient *blcptr = (struct BlacklistClient *) vptr;
 112         bool listed = false;
 113
 114         if (blcptr == NULL || blcptr->client_p == NULL)
 115                 return;
 116
 117         if (blcptr->client_p->preClient == NULL)
 118         {
 119                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 120                                 "blacklist_dns_callback(): blcptr->client_p->preClient (%s) is NULL", get_client_name(blcptr->client_p, HIDE_IP));
 121                 rb_free(blcptr);
 122                 return;
 123         }
 124
 125         if (result != NULL && status)
 126         {
 127                 if (blacklist_check_reply(blcptr, result))
 128                         listed = true;
 129         }
 130
 131         /* they have a blacklist entry for this client */
 132         if (listed && blcptr->client_p->preClient->dnsbl_listed == NULL)
 133         {
 134                 blcptr->client_p->preClient->dnsbl_listed = blcptr->blacklist;
 135                 /* reference to blacklist moves from blcptr to client_p->preClient... */
 136         }
 137         else
 138                 unref_blacklist(blcptr->blacklist);
 139
 140         rb_dlinkDelete(&blcptr->node, &blcptr->client_p->preClient->dnsbl_queries);
 141
 142         /* yes, it can probably happen... */
 143         if (rb_dlink_list_length(&blcptr->client_p->preClient->dnsbl_queries) == 0 && blcptr->client_p->flags & FLAGS_SENTUSER && !EmptyString(blcptr->client_p->name))
 144                 register_local_user(blcptr->client_p, blcptr->client_p);
 145
 146         rb_free(blcptr);
 147 }
 148
 149 static void initiate_blacklist_dnsquery(struct Blacklist *blptr, struct Client *client_p)
 150 {
 151         struct BlacklistClient *blcptr = rb_malloc(sizeof(struct BlacklistClient));
 152         char buf[IRCD_RES_HOSTLEN + 1];
 153         uint8_t *ip;
 154
 155         blcptr->blacklist = blptr;
 156         blcptr->client_p = client_p;
 157
 158         /* IPv4 */
 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                 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 */
 172         else if ((client_p->localClient->ip.ss_family == AF_INET6) && blptr->ipv6)
 173         {
 174                 /* Split up for rDNS lookup
 175                  * ex: ip[0] = 0x00, ip[1] = 0x00... ip[16] = 0x01 for localhost
 176                  * Giving us:
 177                  * 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
 178                  * or something like that.
 179                  */
 180                 ip = (uint8_t *)&((struct sockaddr_in6 *)&client_p->localClient->ip)->sin6_addr.s6_addr;
 181                 char *bufptr = buf;
 182                 int i;
 183
 184                 /* Going backwards */
 185                 for (i = 15; i >= 0; i--, bufptr += 4)
 186                 {
 187                         /* Get upper and lower nibbles */
 188                         uint8_t hi = (ip[i] >> 4) & 0x0F;
 189                         uint8_t lo = ip[i] & 0x0F;
 190
 191                         /* One part... 4 chars + terminator */
 192                         snprintf(bufptr, 5, "%1x.%1x.",
 193                                     (unsigned int) lo, /* Remember, backwards */
 194                                     (unsigned int) hi);
 195                 }
 196
 197                 /* Tack host on */
 198                 strcpy(bufptr, blptr->host);
 199         }
 200         /* This shouldn't happen... */
 201         else
 202                 return;
 203
 204         blcptr->dns_id = lookup_hostname(buf, AF_INET, blacklist_dns_callback, blcptr);
 205
 206         rb_dlinkAdd(blcptr, &blcptr->node, &client_p->preClient->dnsbl_queries);
 207         blptr->refcount++;
 208 }
 209
 210 /* public interfaces */
 211 struct Blacklist *new_blacklist(char *name, char *reject_reason, int ipv4, int ipv6, rb_dlink_list *filters)
 212 {
 213         struct Blacklist *blptr;
 214
 215         if (name == NULL || reject_reason == NULL)
 216                 return NULL;
 217
 218         blptr = find_blacklist(name);
 219         if (blptr == NULL)
 220         {
 221                 blptr = rb_malloc(sizeof(struct Blacklist));
 222                 rb_dlinkAddAlloc(blptr, &blacklist_list);
 223         }
 224         else
 225                 blptr->status &= ~CONF_ILLEGAL;
 226
 227         rb_strlcpy(blptr->host, name, IRCD_RES_HOSTLEN + 1);
 228         rb_strlcpy(blptr->reject_reason, reject_reason, IRCD_BUFSIZE);
 229         blptr->ipv4 = ipv4;
 230         blptr->ipv6 = ipv6;
 231
 232         rb_dlinkMoveList(filters, &blptr->filters);
 233
 234         blptr->lastwarning = 0;
 235
 236         return blptr;
 237 }
 238
 239 void unref_blacklist(struct Blacklist *blptr)
 240 {
 241         rb_dlink_node *ptr, *next_ptr;
 242
 243         blptr->refcount--;
 244         if (blptr->status & CONF_ILLEGAL && blptr->refcount <= 0)
 245         {
 246                 RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blptr->filters.head)
 247                 {
 248                         rb_dlinkDelete(ptr, &blptr->filters);
 249                         rb_free(ptr);
 250                 }
 251
 252                 rb_dlinkFindDestroy(blptr, &blacklist_list);
 253                 rb_free(blptr);
 254         }
 255 }
 256
 257 void lookup_blacklists(struct Client *client_p)
 258 {
 259         rb_dlink_node *nptr;
 260
 261         RB_DLINK_FOREACH(nptr, blacklist_list.head)
 262         {
 263                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
 264
 265                 if (!(blptr->status & CONF_ILLEGAL))
 266                         initiate_blacklist_dnsquery(blptr, client_p);
 267         }
 268 }
 269
 270 void abort_blacklist_queries(struct Client *client_p)
 271 {
 272         rb_dlink_node *ptr, *next_ptr;
 273         struct BlacklistClient *blcptr;
 274
 275         if (client_p->preClient == NULL)
 276                 return;
 277         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, client_p->preClient->dnsbl_queries.head)
 278         {
 279                 blcptr = ptr->data;
 280                 rb_dlinkDelete(&blcptr->node, &client_p->preClient->dnsbl_queries);
 281                 unref_blacklist(blcptr->blacklist);
 282                 cancel_lookup(blcptr->dns_id);
 283                 rb_free(blcptr);
 284         }
 285 }
 286
 287 void destroy_blacklists(void)
 288 {
 289         rb_dlink_node *ptr, *next_ptr;
 290         struct Blacklist *blptr;
 291
 292         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blacklist_list.head)
 293         {
 294                 blptr = ptr->data;
 295                 blptr->hits = 0; /* keep it simple and consistent */
 296                 if (blptr->refcount > 0)
 297                         blptr->status |= CONF_ILLEGAL;
 298                 else
 299                 {
 300                         rb_free(ptr->data);
 301                         rb_dlinkDestroy(ptr, &blacklist_list);
 302                 }
 303         }
 304 }