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  */
  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 void blacklist_dns_callback(void *vptr, struct DNSReply *reply)
  63 {
  64         struct BlacklistClient *blcptr = (struct BlacklistClient *) vptr;
  65         int listed = 0;
  66
  67         if (blcptr == NULL || blcptr->client_p == NULL)
  68                 return;
  69
  70         if (blcptr->client_p->preClient == NULL)
  71         {
  72                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
  73                                 "blacklist_dns_callback(): blcptr->client_p->preClient (%s) is NULL", get_client_name(blcptr->client_p, HIDE_IP));
  74                 rb_free(blcptr);
  75                 return;
  76         }
  77
  78         if (reply != NULL)
  79         {
  80                 /* only accept 127.x.y.z as a listing */
  81                 if (reply->addr.ss_family == AF_INET &&
  82                                 !memcmp(&((struct sockaddr_in *)&reply->addr)->sin_addr, "\177", 1))
  83                         listed = TRUE;
  84                 else if (blcptr->blacklist->lastwarning + 3600 < rb_current_time())
  85                 {
  86                         sendto_realops_snomask(SNO_GENERAL, L_ALL,
  87                                         "Garbage reply from blacklist %s",
  88                                         blcptr->blacklist->host);
  89                         blcptr->blacklist->lastwarning = rb_current_time();
  90                 }
  91         }
  92
  93         /* they have a blacklist entry for this client */
  94         if (listed && blcptr->client_p->preClient->dnsbl_listed == NULL)
  95         {
  96                 blcptr->client_p->preClient->dnsbl_listed = blcptr->blacklist;
  97                 /* reference to blacklist moves from blcptr to client_p->preClient... */
  98         }
  99         else
 100                 unref_blacklist(blcptr->blacklist);
 101
 102         rb_dlinkDelete(&blcptr->node, &blcptr->client_p->preClient->dnsbl_queries);
 103
 104         /* yes, it can probably happen... */
 105         if (rb_dlink_list_length(&blcptr->client_p->preClient->dnsbl_queries) == 0 && blcptr->client_p->flags & FLAGS_SENTUSER && !EmptyString(blcptr->client_p->name))
 106         {
 107                 char buf[USERLEN + 1];
 108                 rb_strlcpy(buf, blcptr->client_p->username, sizeof buf);
 109                 register_local_user(blcptr->client_p, blcptr->client_p, buf);
 110         }
 111
 112         rb_free(blcptr);
 113 }
 114
 115 /* XXX: no IPv6 implementation, not to concerned right now though. */
 116 static void initiate_blacklist_dnsquery(struct Blacklist *blptr, struct Client *client_p)
 117 {
 118         struct BlacklistClient *blcptr = rb_malloc(sizeof(struct BlacklistClient));
 119         char buf[IRCD_RES_HOSTLEN + 1];
 120         int ip[4];
 121
 122         blcptr->blacklist = blptr;
 123         blcptr->client_p = client_p;
 124
 125         blcptr->dns_query.ptr = blcptr;
 126         blcptr->dns_query.callback = blacklist_dns_callback;
 127
 128         /* XXX: yes I know this is bad, I don't really care right now */
 129         sscanf(client_p->sockhost, "%d.%d.%d.%d", &ip[3], &ip[2], &ip[1], &ip[0]);
 130
 131         /* becomes 2.0.0.127.torbl.ahbl.org or whatever */
 132         rb_snprintf(buf, sizeof buf, "%d.%d.%d.%d.%s", ip[0], ip[1], ip[2], ip[3], blptr->host);
 133
 134         gethost_byname_type(buf, &blcptr->dns_query, T_A);
 135
 136         rb_dlinkAdd(blcptr, &blcptr->node, &client_p->preClient->dnsbl_queries);
 137         blptr->refcount++;
 138 }
 139
 140 /* public interfaces */
 141 struct Blacklist *new_blacklist(char *name, char *reject_reason)
 142 {
 143         struct Blacklist *blptr;
 144
 145         if (name == NULL || reject_reason == NULL)
 146                 return NULL;
 147
 148         blptr = find_blacklist(name);
 149         if (blptr == NULL)
 150         {
 151                 blptr = rb_malloc(sizeof(struct Blacklist));
 152                 rb_dlinkAddAlloc(blptr, &blacklist_list);
 153         }
 154         else
 155                 blptr->status &= ~CONF_ILLEGAL;
 156         rb_strlcpy(blptr->host, name, IRCD_RES_HOSTLEN + 1);
 157         rb_strlcpy(blptr->reject_reason, reject_reason, IRCD_BUFSIZE);
 158         blptr->lastwarning = 0;
 159
 160         return blptr;
 161 }
 162
 163 void unref_blacklist(struct Blacklist *blptr)
 164 {
 165         blptr->refcount--;
 166         if (blptr->status & CONF_ILLEGAL && blptr->refcount <= 0)
 167         {
 168                 rb_dlinkFindDestroy(blptr, &blacklist_list);
 169                 rb_free(blptr);
 170         }
 171 }
 172
 173 void lookup_blacklists(struct Client *client_p)
 174 {
 175         rb_dlink_node *nptr;
 176
 177         /* We don't do IPv6 right now, sorry! */
 178         if (client_p->localClient->ip.ss_family == AF_INET6)
 179                 return;
 180
 181         RB_DLINK_FOREACH(nptr, blacklist_list.head)
 182         {
 183                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
 184
 185                 if (!(blptr->status & CONF_ILLEGAL))
 186                         initiate_blacklist_dnsquery(blptr, client_p);
 187         }
 188 }
 189
 190 void abort_blacklist_queries(struct Client *client_p)
 191 {
 192         rb_dlink_node *ptr, *next_ptr;
 193         struct BlacklistClient *blcptr;
 194
 195         if (client_p->preClient == NULL)
 196                 return;
 197         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, client_p->preClient->dnsbl_queries.head)
 198         {
 199                 blcptr = ptr->data;
 200                 rb_dlinkDelete(&blcptr->node, &client_p->preClient->dnsbl_queries);
 201                 unref_blacklist(blcptr->blacklist);
 202                 delete_resolver_queries(&blcptr->dns_query);
 203                 rb_free(blcptr);
 204         }
 205 }
 206
 207 void destroy_blacklists(void)
 208 {
 209         rb_dlink_node *ptr, *next_ptr;
 210         struct Blacklist *blptr;
 211
 212         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blacklist_list.head)
 213         {
 214                 blptr = ptr->data;
 215                 blptr->hits = 0; /* keep it simple and consistent */
 216                 if (blptr->refcount > 0)
 217                         blptr->status |= CONF_ILLEGAL;
 218                 else
 219                 {
 220                         rb_free(ptr->data);
 221                         rb_dlinkDestroy(ptr, &blacklist_list);
 222                 }
 223         }
 224 }