src/blacklist.c

   1 /*
   2  * charybdis: A slightly useful ircd.
   3  * blacklist.c: Manages DNS blacklist entries and lookups
   4  *
   5  * Copyright (C) 2006-2008 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  * $Id: blacklist.c 2743 2006-11-10 15:15:00Z jilles $
  34  */
  35
  36 #include "stdinc.h"
  37 #include "client.h"
  38 #include "res.h"
  39 #include "numeric.h"
  40 #include "reject.h"
  41 #include "s_conf.h"
  42 #include "s_user.h"
  43 #include "blacklist.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 void blacklist_dns_callback(void *vptr, struct DNSReply *reply)
  64 {
  65         struct BlacklistClient *blcptr = (struct BlacklistClient *) vptr;
  66         int listed = 0;
  67
  68         if (blcptr == NULL || blcptr->client_p == NULL)
  69                 return;
  70
  71         if (blcptr->client_p->preClient == NULL)
  72         {
  73                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
  74                                 "blacklist_dns_callback(): blcptr->client_p->preClient (%s) is NULL", get_client_name(blcptr->client_p, HIDE_IP));
  75                 rb_free(blcptr);
  76                 return;
  77         }
  78
  79         if (reply != NULL)
  80         {
  81                 /* only accept 127.x.y.z as a listing */
  82                 if (reply->addr.ss_family == AF_INET &&
  83                                 !memcmp(&((struct sockaddr_in *)&reply->addr)->sin_addr, "\177", 1))
  84                         listed = TRUE;
  85                 else if (blcptr->blacklist->lastwarning + 3600 < rb_current_time())
  86                 {
  87                         sendto_realops_snomask(SNO_GENERAL, L_ALL,
  88                                         "Garbage reply from blacklist %s",
  89                                         blcptr->blacklist->host);
  90                         blcptr->blacklist->lastwarning = rb_current_time();
  91                 }
  92         }
  93
  94         /* they have a blacklist entry for this client */
  95         if (listed && blcptr->client_p->preClient->dnsbl_listed == NULL)
  96         {
  97                 blcptr->client_p->preClient->dnsbl_listed = blcptr->blacklist;
  98                 /* reference to blacklist moves from blcptr to client_p->preClient... */
  99         }
 100         else
 101                 unref_blacklist(blcptr->blacklist);
 102
 103         rb_dlinkDelete(&blcptr->node, &blcptr->client_p->preClient->dnsbl_queries);
 104
 105         /* yes, it can probably happen... */
 106         if (rb_dlink_list_length(&blcptr->client_p->preClient->dnsbl_queries) == 0 && blcptr->client_p->flags & FLAGS_SENTUSER && !EmptyString(blcptr->client_p->name))
 107         {
 108                 char buf[USERLEN + 1];
 109                 rb_strlcpy(buf, blcptr->client_p->username, sizeof buf);
 110                 register_local_user(blcptr->client_p, blcptr->client_p, buf);
 111         }
 112
 113         rb_free(blcptr);
 114 }
 115
 116 /* XXX: no IPv6 implementation, not to concerned right now though. */
 117 static void initiate_blacklist_dnsquery(struct Blacklist *blptr, struct Client *client_p)
 118 {
 119         struct BlacklistClient *blcptr = rb_malloc(sizeof(struct BlacklistClient));
 120         char buf[IRCD_RES_HOSTLEN + 1];
 121         int ip[4];
 122
 123         blcptr->blacklist = blptr;
 124         blcptr->client_p = client_p;
 125
 126         blcptr->dns_query.ptr = blcptr;
 127         blcptr->dns_query.callback = blacklist_dns_callback;
 128
 129         /* XXX: yes I know this is bad, I don't really care right now */
 130         sscanf(client_p->sockhost, "%d.%d.%d.%d", &ip[3], &ip[2], &ip[1], &ip[0]);
 131
 132         /* becomes 2.0.0.127.torbl.ahbl.org or whatever */
 133         rb_snprintf(buf, sizeof buf, "%d.%d.%d.%d.%s", ip[0], ip[1], ip[2], ip[3], blptr->host);
 134
 135         gethost_byname_type(buf, &blcptr->dns_query, T_A);
 136
 137         rb_dlinkAdd(blcptr, &blcptr->node, &client_p->preClient->dnsbl_queries);
 138         blptr->refcount++;
 139 }
 140
 141 /* public interfaces */
 142 struct Blacklist *new_blacklist(char *name, char *reject_reason)
 143 {
 144         struct Blacklist *blptr;
 145
 146         if (name == NULL || reject_reason == NULL)
 147                 return NULL;
 148
 149         blptr = find_blacklist(name);
 150         if (blptr == NULL)
 151         {
 152                 blptr = rb_malloc(sizeof(struct Blacklist));
 153                 rb_dlinkAddAlloc(blptr, &blacklist_list);
 154         }
 155         else
 156                 blptr->status &= ~CONF_ILLEGAL;
 157         rb_strlcpy(blptr->host, name, IRCD_RES_HOSTLEN + 1);
 158         rb_strlcpy(blptr->reject_reason, reject_reason, IRCD_BUFSIZE);
 159         blptr->lastwarning = 0;
 160
 161         return blptr;
 162 }
 163
 164 void unref_blacklist(struct Blacklist *blptr)
 165 {
 166         blptr->refcount--;
 167         if (blptr->status & CONF_ILLEGAL && blptr->refcount <= 0)
 168         {
 169                 rb_dlinkFindDestroy(blptr, &blacklist_list);
 170                 rb_free(blptr);
 171         }
 172 }
 173
 174 void lookup_blacklists(struct Client *client_p)
 175 {
 176         rb_dlink_node *nptr;
 177
 178         /* We don't do IPv6 right now, sorry! */
 179         if (client_p->localClient->ip.ss_family == AF_INET6)
 180                 return;
 181
 182         RB_DLINK_FOREACH(nptr, blacklist_list.head)
 183         {
 184                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
 185
 186                 if (!(blptr->status & CONF_ILLEGAL))
 187                         initiate_blacklist_dnsquery(blptr, client_p);
 188         }
 189 }
 190
 191 void abort_blacklist_queries(struct Client *client_p)
 192 {
 193         rb_dlink_node *ptr, *next_ptr;
 194         struct BlacklistClient *blcptr;
 195
 196         if (client_p->preClient == NULL)
 197                 return;
 198         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, client_p->preClient->dnsbl_queries.head)
 199         {
 200                 blcptr = ptr->data;
 201                 rb_dlinkDelete(&blcptr->node, &client_p->preClient->dnsbl_queries);
 202                 unref_blacklist(blcptr->blacklist);
 203                 delete_resolver_queries(&blcptr->dns_query);
 204                 rb_free(blcptr);
 205         }
 206 }
 207
 208 void destroy_blacklists(void)
 209 {
 210         rb_dlink_node *ptr, *next_ptr;
 211         struct Blacklist *blptr;
 212
 213         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blacklist_list.head)
 214         {
 215                 blptr = ptr->data;
 216                 blptr->hits = 0; /* keep it simple and consistent */
 217                 if (blptr->refcount > 0)
 218                         blptr->status |= CONF_ILLEGAL;
 219                 else
 220                 {
 221                         rb_free(ptr->data);
 222                         rb_dlinkDestroy(ptr, &blacklist_list);
 223                 }
 224         }
 225 }