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
  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, struct rb_sockaddr_storage *addr)
  63 {
  64         struct Blacklist *blptr = blcptr->blacklist;
  65         char ipaddr[HOSTIPLEN];
  66         char *lastoctet;
  67         rb_dlink_node *ptr;
  68
  69         /* XXX the below two checks might want to change at some point
  70          * e.g. if IPv6 blacklists don't use 127.x.y.z or A records anymore
  71          * --Elizabeth
  72          */
  73         if (addr->ss_family != AF_INET ||
  74                         memcmp(&((struct sockaddr_in *)addr)->sin_addr, "\177", 1))
  75                 goto blwarn;
  76
  77         /* No filters and entry found - thus positive match */
  78         if (!rb_dlink_list_length(&blptr->filters))
  79                 return 1;
  80
  81         rb_inet_ntop_sock((struct sockaddr *)addr, ipaddr, sizeof(ipaddr));
  82
  83         /* Below will prolly have to change too if the above changes */
  84         if ((lastoctet = strrchr(ipaddr, '.')) == NULL || *(++lastoctet) == '\0')
  85                 goto blwarn;
  86
  87         RB_DLINK_FOREACH(ptr, blcptr->blacklist->filters.head)
  88         {
  89                 struct BlacklistFilter *filter = ptr->data;
  90                 char *cmpstr;
  91
  92                 if (filter->type == BLACKLIST_FILTER_ALL)
  93                         cmpstr = ipaddr;
  94                 else if (filter->type == BLACKLIST_FILTER_LAST)
  95                         cmpstr = lastoctet;
  96                 else
  97                 {
  98                         sendto_realops_snomask(SNO_GENERAL, L_ALL,
  99                                         "blacklist_check_reply(): Unknown filtertype (BUG!)");
 100                         continue;
 101                 }
 102
 103                 if (strcmp(cmpstr, filter->filterstr) == 0)
 104                         /* Match! */
 105                         return 1;
 106         }
 107
 108         return 0;
 109 blwarn:
 110         if (blcptr->blacklist->lastwarning + 3600 < rb_current_time())
 111         {
 112                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 113                                 "Garbage reply from blacklist %s",
 114                                 blcptr->blacklist->host);
 115                 blcptr->blacklist->lastwarning = rb_current_time();
 116         }
 117         return 0;
 118 }
 119
 120 static void blacklist_dns_callback(void *vptr, struct DNSReply *reply)
 121 {
 122         struct BlacklistClient *blcptr = (struct BlacklistClient *) vptr;
 123         int listed = 0;
 124
 125         if (blcptr == NULL || blcptr->client_p == NULL)
 126                 return;
 127
 128         if (blcptr->client_p->preClient == NULL)
 129         {
 130                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 131                                 "blacklist_dns_callback(): blcptr->client_p->preClient (%s) is NULL", get_client_name(blcptr->client_p, HIDE_IP));
 132                 rb_free(blcptr);
 133                 return;
 134         }
 135
 136         if (reply != NULL)
 137         {
 138                 if (blacklist_check_reply(blcptr, &reply->addr))
 139                         listed = TRUE;
 140         }
 141
 142         /* they have a blacklist entry for this client */
 143         if (listed && blcptr->client_p->preClient->dnsbl_listed == NULL)
 144         {
 145                 blcptr->client_p->preClient->dnsbl_listed = blcptr->blacklist;
 146                 /* reference to blacklist moves from blcptr to client_p->preClient... */
 147         }
 148         else
 149                 unref_blacklist(blcptr->blacklist);
 150
 151         rb_dlinkDelete(&blcptr->node, &blcptr->client_p->preClient->dnsbl_queries);
 152
 153         /* yes, it can probably happen... */
 154         if (rb_dlink_list_length(&blcptr->client_p->preClient->dnsbl_queries) == 0 && blcptr->client_p->flags & FLAGS_SENTUSER && !EmptyString(blcptr->client_p->name))
 155         {
 156                 char buf[USERLEN + 1];
 157                 rb_strlcpy(buf, blcptr->client_p->username, sizeof buf);
 158                 register_local_user(blcptr->client_p, blcptr->client_p, buf);
 159         }
 160
 161         rb_free(blcptr);
 162 }
 163
 164 static void initiate_blacklist_dnsquery(struct Blacklist *blptr, struct Client *client_p)
 165 {
 166         struct BlacklistClient *blcptr = rb_malloc(sizeof(struct BlacklistClient));
 167         char buf[IRCD_RES_HOSTLEN + 1];
 168         uint8_t *ip;
 169
 170         blcptr->blacklist = blptr;
 171         blcptr->client_p = client_p;
 172
 173         blcptr->dns_query.ptr = blcptr;
 174         blcptr->dns_query.callback = blacklist_dns_callback;
 175
 176         if ((client_p->localClient->ip.ss_family == AF_INET) && blptr->ipv4)
 177         {
 178                 ip = (uint8_t *)&((struct sockaddr_in *)&client_p->localClient->ip)->sin_addr.s_addr;
 179
 180                 /* becomes 2.0.0.127.torbl.ahbl.org or whatever */
 181                 rb_snprintf(buf, sizeof buf, "%d.%d.%d.%d.%s",
 182                             (unsigned int) ip[3],
 183                             (unsigned int) ip[2],
 184                             (unsigned int) ip[1],
 185                             (unsigned int) ip[0],
 186                             blptr->host);
 187         }
 188         /* IPv6 is supported now. --Elizabeth */
 189         else if ((client_p->localClient->ip.ss_family == AF_INET6) && blptr->ipv6)
 190         {
 191                 /* Breaks it into ip[0] = 0x00, ip[1] = 0x00... ip[16] = 0x01 for localhost
 192                  * I wish there was a uint4_t for C, this would make the below cleaner, but... */
 193                 ip = (uint8_t *)&((struct sockaddr_in6 *)&client_p->localClient->ip)->sin6_addr.s6_addr;
 194                 char *bufptr = buf;
 195                 int i;
 196
 197                 /* The below will give us something like
 198                  * 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
 199                  */
 200
 201                 /* Going backwards */
 202                 for (i = 15; i >= 0; i--)
 203                 {
 204                         /* Get upper and lower nibbles (yes this works fine on
 205                          * both big and little endian) */
 206                         uint8_t hi = (ip[i] >> 4) & 0x0F;
 207                         uint8_t lo = ip[i] & 0x0F;
 208
 209                         /* One part... (why 5? rb_snprintf adds \0) */
 210                         rb_snprintf(bufptr, 5, "%1x.%1x.",
 211                                     (unsigned int) lo, /* Remember, backwards */
 212                                     (unsigned int) hi);
 213
 214                         /* Lurch forward to next position */
 215                         bufptr += 4;
 216                 }
 217
 218                 /* Tack host on */
 219                 strcpy(bufptr, blptr->host);
 220         }
 221         /* This shouldn't happen... */
 222         else
 223                 return;
 224
 225         gethost_byname_type(buf, &blcptr->dns_query, T_A);
 226
 227         rb_dlinkAdd(blcptr, &blcptr->node, &client_p->preClient->dnsbl_queries);
 228         blptr->refcount++;
 229 }
 230
 231 /* public interfaces */
 232 struct Blacklist *new_blacklist(char *name, char *reject_reason, int ipv4, int ipv6, rb_dlink_list *filters)
 233 {
 234         struct Blacklist *blptr;
 235
 236         if (name == NULL || reject_reason == NULL)
 237                 return NULL;
 238
 239         blptr = find_blacklist(name);
 240         if (blptr == NULL)
 241         {
 242                 blptr = rb_malloc(sizeof(struct Blacklist));
 243                 rb_dlinkAddAlloc(blptr, &blacklist_list);
 244         }
 245         else
 246                 blptr->status &= ~CONF_ILLEGAL;
 247
 248         rb_strlcpy(blptr->host, name, IRCD_RES_HOSTLEN + 1);
 249         rb_strlcpy(blptr->reject_reason, reject_reason, IRCD_BUFSIZE);
 250         blptr->ipv4 = ipv4;
 251         blptr->ipv6 = ipv6;
 252
 253         rb_dlinkMoveList(filters, &blptr->filters);
 254
 255         blptr->lastwarning = 0;
 256
 257         return blptr;
 258 }
 259
 260 void unref_blacklist(struct Blacklist *blptr)
 261 {
 262         rb_dlink_node *ptr, *next_ptr;
 263
 264         blptr->refcount--;
 265         if (blptr->status & CONF_ILLEGAL && blptr->refcount <= 0)
 266         {
 267                 RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blptr->filters.head)
 268                 {
 269                         rb_free(ptr);
 270                         rb_dlinkDelete(ptr, &blptr->filters);
 271                 }
 272
 273                 rb_dlinkFindDestroy(blptr, &blacklist_list);
 274                 rb_free(blptr);
 275         }
 276 }
 277
 278 void lookup_blacklists(struct Client *client_p)
 279 {
 280         rb_dlink_node *nptr;
 281
 282         RB_DLINK_FOREACH(nptr, blacklist_list.head)
 283         {
 284                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
 285
 286                 if (!(blptr->status & CONF_ILLEGAL))
 287                         initiate_blacklist_dnsquery(blptr, client_p);
 288         }
 289 }
 290
 291 void abort_blacklist_queries(struct Client *client_p)
 292 {
 293         rb_dlink_node *ptr, *next_ptr;
 294         struct BlacklistClient *blcptr;
 295
 296         if (client_p->preClient == NULL)
 297                 return;
 298         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, client_p->preClient->dnsbl_queries.head)
 299         {
 300                 blcptr = ptr->data;
 301                 rb_dlinkDelete(&blcptr->node, &client_p->preClient->dnsbl_queries);
 302                 unref_blacklist(blcptr->blacklist);
 303                 delete_resolver_queries(&blcptr->dns_query);
 304                 rb_free(blcptr);
 305         }
 306 }
 307
 308 void destroy_blacklists(void)
 309 {
 310         rb_dlink_node *ptr, *next_ptr;
 311         struct Blacklist *blptr;
 312
 313         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blacklist_list.head)
 314         {
 315                 blptr = ptr->data;
 316                 blptr->hits = 0; /* keep it simple and consistent */
 317                 if (blptr->refcount > 0)
 318                         blptr->status |= CONF_ILLEGAL;
 319                 else
 320                 {
 321                         rb_free(ptr->data);
 322                         rb_dlinkDestroy(ptr, &blacklist_list);
 323                 }
 324         }
 325 }