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 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 static void initiate_blacklist_dnsquery(struct Blacklist *blptr, struct Client *client_p)
 116 {
 117         struct BlacklistClient *blcptr = rb_malloc(sizeof(struct BlacklistClient));
 118         char buf[IRCD_RES_HOSTLEN + 1];
 119         uint8_t *ip;
 120
 121         blcptr->blacklist = blptr;
 122         blcptr->client_p = client_p;
 123
 124         blcptr->dns_query.ptr = blcptr;
 125         blcptr->dns_query.callback = blacklist_dns_callback;
 126
 127         if ((client_p->localClient->ip.ss_family == AF_INET) && blptr->ipv4)
 128         {
 129                 ip = (uint8_t *)&((struct sockaddr_in *)&client_p->localClient->ip)->sin_addr.s_addr;
 130
 131                 /* becomes 2.0.0.127.torbl.ahbl.org or whatever */
 132                 rb_snprintf(buf, sizeof buf, "%d.%d.%d.%d.%s",
 133                             (unsigned int) ip[3],
 134                             (unsigned int) ip[2],
 135                             (unsigned int) ip[1],
 136                             (unsigned int) ip[0],
 137                             blptr->host);
 138         }
 139         /* IPv6 is supported now. --Elizabeth */
 140         else if ((client_p->localClient->ip.ss_family == AF_INET6) && blptr->ipv6)
 141         {
 142                 /* Breaks it into ip[0] = 0x00, ip[1] = 0x00... ip[16] = 0x01 for localhost
 143                  * I wish there was a uint4_t for C, this would make the below cleaner, but... */
 144                 ip = (uint8_t *)&((struct sockaddr_in6 *)&client_p->localClient->ip)->sin6_addr.s6_addr;
 145                 char *bufptr = buf;
 146                 int i;
 147
 148                 /* The below will give us something like
 149                  * 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
 150                  */
 151
 152                 /* Going backwards */
 153                 for (i = 15; i >= 0; i--)
 154                 {
 155                         /* Get upper and lower nibbles (yes this works fine on
 156                          * both big and little endian) */
 157                         uint8_t hi = (ip[i] >> 4) & 0x0F;
 158                         uint8_t lo = ip[i] & 0x0F;
 159
 160                         /* One part... (why 5? rb_snprintf adds \0) */
 161                         rb_snprintf(bufptr, 5, "%1x.%1x.",
 162                                     (unsigned int) lo, /* Remember, backwards */
 163                                     (unsigned int) hi);
 164
 165                         /* Lurch forward to next position */
 166                         bufptr += 4;
 167                 }
 168
 169                 /* Tack host on */
 170                 strcpy(bufptr, blptr->host);
 171         }
 172         /* This shouldn't happen... */
 173         else
 174                 return;
 175
 176         gethost_byname_type(buf, &blcptr->dns_query, T_A);
 177
 178         rb_dlinkAdd(blcptr, &blcptr->node, &client_p->preClient->dnsbl_queries);
 179         blptr->refcount++;
 180 }
 181
 182 /* public interfaces */
 183 struct Blacklist *new_blacklist(char *name, char *reject_reason, int ipv4, int ipv6)
 184 {
 185         struct Blacklist *blptr;
 186
 187         if (name == NULL || reject_reason == NULL)
 188                 return NULL;
 189
 190         blptr = find_blacklist(name);
 191         if (blptr == NULL)
 192         {
 193                 blptr = rb_malloc(sizeof(struct Blacklist));
 194                 rb_dlinkAddAlloc(blptr, &blacklist_list);
 195         }
 196         else
 197                 blptr->status &= ~CONF_ILLEGAL;
 198         rb_strlcpy(blptr->host, name, IRCD_RES_HOSTLEN + 1);
 199         rb_strlcpy(blptr->reject_reason, reject_reason, IRCD_BUFSIZE);
 200         blptr->ipv4 = ipv4;
 201         blptr->ipv6 = ipv6;
 202         blptr->lastwarning = 0;
 203
 204         return blptr;
 205 }
 206
 207 void unref_blacklist(struct Blacklist *blptr)
 208 {
 209         blptr->refcount--;
 210         if (blptr->status & CONF_ILLEGAL && blptr->refcount <= 0)
 211         {
 212                 rb_dlinkFindDestroy(blptr, &blacklist_list);
 213                 rb_free(blptr);
 214         }
 215 }
 216
 217 void lookup_blacklists(struct Client *client_p)
 218 {
 219         rb_dlink_node *nptr;
 220
 221         RB_DLINK_FOREACH(nptr, blacklist_list.head)
 222         {
 223                 struct Blacklist *blptr = (struct Blacklist *) nptr->data;
 224
 225                 if (!(blptr->status & CONF_ILLEGAL))
 226                         initiate_blacklist_dnsquery(blptr, client_p);
 227         }
 228 }
 229
 230 void abort_blacklist_queries(struct Client *client_p)
 231 {
 232         rb_dlink_node *ptr, *next_ptr;
 233         struct BlacklistClient *blcptr;
 234
 235         if (client_p->preClient == NULL)
 236                 return;
 237         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, client_p->preClient->dnsbl_queries.head)
 238         {
 239                 blcptr = ptr->data;
 240                 rb_dlinkDelete(&blcptr->node, &client_p->preClient->dnsbl_queries);
 241                 unref_blacklist(blcptr->blacklist);
 242                 delete_resolver_queries(&blcptr->dns_query);
 243                 rb_free(blcptr);
 244         }
 245 }
 246
 247 void destroy_blacklists(void)
 248 {
 249         rb_dlink_node *ptr, *next_ptr;
 250         struct Blacklist *blptr;
 251
 252         RB_DLINK_FOREACH_SAFE(ptr, next_ptr, blacklist_list.head)
 253         {
 254                 blptr = ptr->data;
 255                 blptr->hits = 0; /* keep it simple and consistent */
 256                 if (blptr->refcount > 0)
 257                         blptr->status |= CONF_ILLEGAL;
 258                 else
 259                 {
 260                         rb_free(ptr->data);
 261                         rb_dlinkDestroy(ptr, &blacklist_list);
 262                 }
 263         }
 264 }