extensions/ip_cloaking.c

   1
   2 #include "stdinc.h"
   3 #include "modules.h"
   4 #include "hook.h"
   5 #include "client.h"
   6 #include "ircd.h"
   7 #include "send.h"
   8 #include "hash.h"
   9 #include "s_conf.h"
  10 #include "s_user.h"
  11 #include "s_serv.h"
  12 #include "numeric.h"
  13
  14 /* if you're modifying this module, you'll probably to change this */
  15 #define KEY 0x13748cfa
  16
  17 static int
  18 _modinit(void)
  19 {
  20         /* add the usermode to the available slot */
  21         user_modes['x'] = find_umode_slot();
  22         construct_umodebuf();
  23
  24         return 0;
  25 }
  26
  27 static void
  28 _moddeinit(void)
  29 {
  30         /* disable the umode and remove it from the available list */
  31         user_modes['x'] = 0;
  32         construct_umodebuf();
  33 }
  34
  35 static void check_umode_change(void *data);
  36 static void check_new_user(void *data);
  37 mapi_hfn_list_av1 ip_cloaking_hfnlist[] = {
  38         { "umode_changed", (hookfn) check_umode_change },
  39         { "new_local_user", (hookfn) check_new_user },
  40         { NULL, NULL }
  41 };
  42
  43 DECLARE_MODULE_AV1(ip_cloaking, _modinit, _moddeinit, NULL, NULL,
  44                         ip_cloaking_hfnlist, "$Revision: 3526 $");
  45
  46 static void
  47 distribute_hostchange(struct Client *client)
  48 {
  49         if (irccmp(client->host, client->orighost))
  50                 sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :is now your hidden host",
  51                         client->host);
  52         else
  53                 sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :hostname reset",
  54                         client->host);
  55
  56         sendto_server(NULL, NULL,
  57                 CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s",
  58                 use_id(&me), use_id(client), client->host);
  59         sendto_server(NULL, NULL,
  60                 CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s",
  61                 use_id(&me), use_id(client), client->host);
  62         if (irccmp(client->host, client->orighost))
  63                 SetDynSpoof(client);
  64         else
  65                 ClearDynSpoof(client);
  66 }
  67
  68 static void
  69 do_host_cloak_ip(const char *inbuf, char *outbuf)
  70 {
  71         /* None of the characters in this table can be valid in an IP */
  72         char chartable[] = "ghijklmnopqrstuvwxyz";
  73         char *tptr;
  74         uint32_t accum = fnv_hash((const unsigned char*) inbuf, 32);
  75         int sepcount = 0;
  76         int totalcount = 0;
  77         int ipv6 = 0;
  78
  79         rb_strlcpy(outbuf, inbuf, HOSTLEN + 1);
  80
  81         if (strchr(outbuf, ':'))
  82         {
  83                 ipv6 = 1;
  84
  85                 /* Damn you IPv6...
  86                  * We count the number of colons so we can calculate how much
  87                  * of the host to cloak. This is because some hostmasks may not
  88                  * have as many octets as we'd like.
  89                  *
  90                  * We have to do this ahead of time because doing this during
  91                  * the actual cloaking would get ugly
  92                  */
  93                 for (tptr = outbuf; *tptr != '\0'; tptr++)
  94                         if (*tptr == ':')
  95                                 totalcount++;
  96         }
  97         else if (!strchr(outbuf, '.'))
  98                 return;
  99
 100         for (tptr = outbuf; *tptr != '\0'; tptr++)
 101         {
 102                 if (*tptr == ':' || *tptr == '.')
 103                 {
 104                         sepcount++;
 105                         continue;
 106                 }
 107
 108                 if (ipv6 && sepcount < totalcount / 2)
 109                         continue;
 110
 111                 if (!ipv6 && sepcount < 2)
 112                         continue;
 113
 114                 *tptr = chartable[(*tptr + accum) % 20];
 115                 accum = (accum << 1) | (accum >> 31);
 116         }
 117 }
 118
 119 static void
 120 do_host_cloak_host(const char *inbuf, char *outbuf)
 121 {
 122         char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz";
 123         char *tptr;
 124         uint32_t accum = fnv_hash((const unsigned char*) inbuf, 32);
 125
 126         rb_strlcpy(outbuf, inbuf, HOSTLEN + 1);
 127
 128         /* pass 1: scramble first section of hostname using base26
 129          * alphabet toasted against the FNV hash of the string.
 130          *
 131          * numbers are not changed at this time, only letters.
 132          */
 133         for (tptr = outbuf; *tptr != '\0'; tptr++)
 134         {
 135                 if (*tptr == '.')
 136                         break;
 137
 138                 if (isdigit(*tptr) || *tptr == '-')
 139                         continue;
 140
 141                 *tptr = b26_alphabet[(*tptr + accum) % 26];
 142
 143                 /* Rotate one bit to avoid all digits being turned odd or even */
 144                 accum = (accum << 1) | (accum >> 31);
 145         }
 146
 147         /* pass 2: scramble each number in the address */
 148         for (tptr = outbuf; *tptr != '\0'; tptr++)
 149         {
 150                 if (isdigit(*tptr))
 151                         *tptr = '0' + (*tptr + accum) % 10;
 152
 153                 accum = (accum << 1) | (accum >> 31);
 154         }
 155 }
 156
 157 static void
 158 check_umode_change(void *vdata)
 159 {
 160         hook_data_umode_changed *data = (hook_data_umode_changed *)vdata;
 161         struct Client *source_p = data->client;
 162
 163         if (!MyClient(source_p))
 164                 return;
 165
 166         /* didn't change +h umode, we don't need to do anything */
 167         if (!((data->oldumodes ^ source_p->umodes) & user_modes['x']))
 168                 return;
 169
 170         if (source_p->umodes & user_modes['x'])
 171         {
 172                 if (IsIPSpoof(source_p) || source_p->localClient->mangledhost == NULL || (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost)))
 173                 {
 174                         source_p->umodes &= ~user_modes['x'];
 175                         return;
 176                 }
 177                 if (strcmp(source_p->host, source_p->localClient->mangledhost))
 178                 {
 179                         rb_strlcpy(source_p->host, source_p->localClient->mangledhost, HOSTLEN + 1);
 180                         distribute_hostchange(source_p);
 181                 }
 182                 else /* not really nice, but we need to send this numeric here */
 183                         sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
 184                                 source_p->host);
 185         }
 186         else if (!(source_p->umodes & user_modes['x']))
 187         {
 188                 if (source_p->localClient->mangledhost != NULL &&
 189                                 !strcmp(source_p->host, source_p->localClient->mangledhost))
 190                 {
 191                         rb_strlcpy(source_p->host, source_p->orighost, HOSTLEN + 1);
 192                         distribute_hostchange(source_p);
 193                 }
 194         }
 195 }
 196
 197 static void
 198 check_new_user(void *vdata)
 199 {
 200         struct Client *source_p = (void *)vdata;
 201
 202         if (IsIPSpoof(source_p))
 203         {
 204                 source_p->umodes &= ~user_modes['x'];
 205                 return;
 206         }
 207         source_p->localClient->mangledhost = rb_malloc(HOSTLEN + 1);
 208         if (!irccmp(source_p->orighost, source_p->sockhost))
 209                 do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost);
 210         else
 211                 do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost);
 212         if (IsDynSpoof(source_p))
 213                 source_p->umodes &= ~user_modes['x'];
 214         if (source_p->umodes & user_modes['x'])
 215         {
 216                 rb_strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host));
 217                 if (irccmp(source_p->host, source_p->orighost))
 218                         SetDynSpoof(source_p);
 219         }
 220 }