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 "tools.h"
  40 #include "memory.h"
  41 #include "numeric.h"
  42 #include "reject.h"
  43 #include "s_conf.h"
  44 #include "s_user.h"
  45 #include "blacklist.h"
  46
  47 rb_dlink_list blacklist_list = { NULL, NULL, 0 };
  48
  49 /* private interfaces */
  50 static struct Blacklist *find_blacklist(char *name)
  51 {
  52         rb_dlink_node *nptr;
  53
  54         RB_DLINK_FOREACH(nptr, blacklist_list.head)
  55         {
  56                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
  57
  58                 if (!irccmp(blptr->host, name))
  59                         return blptr;
  60         }
  61
  62         return NULL;
  63 }
  64
  65 static void blacklist_dns_callback(void *vptr, struct DNSReply *reply)
  66 {
  67         struct BlacklistClient *blcptr = (struct BlacklistClient *) vptr;
  68         int listed = 0;
  69
  70         if (blcptr == NULL || blcptr->client_p == NULL)
  71                 return;
  72
  73         if (blcptr->client_p->preClient == NULL)
  74         {
  75                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
  76                                 "blacklist_dns_callback(): blcptr->client_p->preClient (%s) is NULL", get_client_name(blcptr->client_p, HIDE_IP));
  77                 MyFree(blcptr);
  78                 return;
  79         }
  80
  81         if (reply != NULL)
  82         {
  83                 /* only accept 127.0.0.x as a listing */
  84                 if (reply->addr.ss_family == AF_INET &&
  85                                 !memcmp(&((struct sockaddr_in *)&reply->addr)->sin_addr, "\177\0\0", 3))
  86                         listed = TRUE;
  87                 else if (blcptr->blacklist->lastwarning + 3600 < CurrentTime)
  88                 {
  89                         sendto_realops_snomask(SNO_GENERAL, L_ALL,
  90                                         "Garbage reply from blacklist %s",
  91                                         blcptr->blacklist->host);
  92                         blcptr->blacklist->lastwarning = CurrentTime;
  93                 }
  94         }
  95
  96         /* they have a blacklist entry for this client */
  97         if (listed && blcptr->client_p->preClient->dnsbl_listed == NULL)
  98         {
  99                 blcptr->client_p->preClient->dnsbl_listed = blcptr->blacklist;
 100                 /* reference to blacklist moves from blcptr to client_p->preClient... */
 101         }
 102         else
 103                 unref_blacklist(blcptr->blacklist);
 104
 105         rb_dlinkDelete(&blcptr->node, &blcptr->client_p->preClient->dnsbl_queries);
 106
 107         /* yes, it can probably happen... */
 108         if (rb_dlink_list_length(&blcptr->client_p->preClient->dnsbl_queries) == 0 && blcptr->client_p->flags & FLAGS_SENTUSER && !EmptyString(blcptr->client_p->name))
 109         {
 110                 char buf[USERLEN + 1];
 111                 strlcpy(buf, blcptr->client_p->username, sizeof buf);
 112                 register_local_user(blcptr->client_p, blcptr->client_p, buf);
 113         }
 114
 115         MyFree(blcptr);
 116 }
 117
 118 /* XXX: no IPv6 implementation, not to concerned right now though. */
 119 static void initiate_blacklist_dnsquery(struct Blacklist *blptr, struct Client *client_p)
 120 {
 121         struct BlacklistClient *blcptr = MyMalloc(sizeof(struct BlacklistClient));
 122         char buf[IRCD_BUFSIZE];
 123         int ip[4];
 124
 125         blcptr->blacklist = blptr;
 126         blcptr->client_p = client_p;
 127
 128         blcptr->dns_query.ptr = blcptr;
 129         blcptr->dns_query.callback = blacklist_dns_callback;
 130
 131         /* XXX: yes I know this is bad, I don't really care right now */
 132         sscanf(client_p->sockhost, "%d.%d.%d.%d", &ip[3], &ip[2], &ip[1], &ip[0]);
 133
 134         /* becomes 2.0.0.127.torbl.ahbl.org or whatever */
 135         rb_snprintf(buf, IRCD_BUFSIZE, "%d.%d.%d.%d.%s", ip[0], ip[1], ip[2], ip[3], blptr->host);
 136
 137         gethost_byname_type(buf, &blcptr->dns_query, T_A);
 138
 139         rb_dlinkAdd(blcptr, &blcptr->node, &client_p->preClient->dnsbl_queries);
 140         blptr->refcount++;
 141 }
 142
 143 /* public interfaces */
 144 struct Blacklist *new_blacklist(char *name, char *reject_reason)
 145 {
 146         struct Blacklist *blptr;
 147
 148         if (name == NULL || reject_reason == NULL)
 149                 return NULL;
 150
 151         blptr = find_blacklist(name);
 152         if (blptr == NULL)
 153         {
 154                 blptr = MyMalloc(sizeof(struct Blacklist));
 155                 rb_dlinkAddAlloc(blptr, &blacklist_list);
 156         }
 157         else
 158                 blptr->status &= ~CONF_ILLEGAL;
 159         strlcpy(blptr->host, name, HOSTLEN);
 160         strlcpy(blptr->reject_reason, reject_reason, IRCD_BUFSIZE);
 161         blptr->lastwarning = 0;
 162
 163         return blptr;
 164 }
 165
 166 void unref_blacklist(struct Blacklist *blptr)
 167 {
 168         blptr->refcount--;
 169         if (blptr->status & CONF_ILLEGAL && blptr->refcount <= 0)
 170         {
 171                 rb_dlinkFindDestroy(blptr, &blacklist_list);
 172                 MyFree(blptr);
 173         }
 174 }
 175
 176 void lookup_blacklists(struct Client *client_p)
 177 {
 178         rb_dlink_node *nptr;
 179
 180         /* We don't do IPv6 right now, sorry! */
 181         if (client_p->localClient->ip.ss_family == AF_INET6)
 182                 return;
 183
 184         RB_DLINK_FOREACH(nptr, blacklist_list.head)
 185         {
 186                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
 187
 188                 if (!(blptr->status & CONF_ILLEGAL))
 189                         initiate_blacklist_dnsquery(blptr, client_p);
 190         }
 191 }
 192
 193 void abort_blacklist_queries(struct Client *client_p)
 194 {
 195         rb_dlink_node *ptr, *next_ptr;
 196         struct BlacklistClient *blcptr;
 197
 198         if (client_p->preClient == NULL)
 199                 return;
 200         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, client_p->preClient->dnsbl_queries.head)
 201         {
 202                 blcptr = ptr->data;
 203                 rb_dlinkDelete(&blcptr->node, &client_p->preClient->dnsbl_queries);
 204                 unref_blacklist(blcptr->blacklist);
 205                 delete_resolver_queries(&blcptr->dns_query);
 206                 MyFree(blcptr);
 207         }
 208 }
 209
 210 void destroy_blacklists(void)
 211 {
 212         rb_dlink_node *ptr, *next_ptr;
 213         struct Blacklist *blptr;
 214
 215         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blacklist_list.head)
 216         {
 217                 blptr = ptr->data;
 218                 blptr->hits = 0; /* keep it simple and consistent */
 219                 if (blptr->refcount > 0)
 220                         blptr->status |= CONF_ILLEGAL;
 221                 else
 222                 {
 223                         MyFree(ptr->data);
 224                         rb_dlinkDestroy(ptr, &blacklist_list);
 225                 }
 226         }
 227 }