extensions/ip_cloaking_3.0.c

   1 /* $Id: ip_cloaking.c 3526 2007-07-06 07:56:14Z nenolod $ */
   2
   3 #include "stdinc.h"
   4 #include "modules.h"
   5 #include "hook.h"
   6 #include "client.h"
   7 #include "ircd.h"
   8 #include "send.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['h'] = 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['h'] = 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_p, char *newhost)
  48 {
  49         if (newhost != client_p->orighost)
  50                 sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
  51                         newhost);
  52         else
  53                 sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :hostname reset",
  54                         newhost);
  55
  56         sendto_server(NULL, NULL,
  57                 CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s",
  58                 use_id(&me), use_id(client_p), newhost);
  59         sendto_server(NULL, NULL,
  60                 CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s",
  61                 use_id(&me), use_id(client_p), newhost);
  62
  63         change_nick_user_host(client_p, client_p->name, client_p->username, newhost, 0, "Changing host");
  64
  65         if (newhost != client_p->orighost)
  66                 SetDynSpoof(client_p);
  67         else
  68                 ClearDynSpoof(client_p);
  69 }
  70
  71 #define Nval 0x8c3a48ac
  72 #define HOSTLEN 63
  73 #define INITDATA "98fwqefnoiqefv03f423t34gbv3vb89tg432t3b8" /* change this */
  74
  75 static inline unsigned int
  76 get_string_entropy(const char *inbuf)
  77 {
  78         unsigned int accum = 1;
  79
  80         while(*inbuf != '\0')
  81                 accum += *inbuf++;
  82
  83         return accum;
  84 }
  85
  86 /* calls get_string_entropy() and toasts it against INITDATA */
  87 static inline unsigned int
  88 get_string_weighted_entropy(const char *inbuf)
  89 {
  90         static int base_entropy = 0;
  91         unsigned int accum = get_string_entropy(inbuf);
  92
  93         /* initialize the algorithm if it is not yet ready */
  94         if (base_entropy == 0)
  95                 base_entropy = get_string_entropy(INITDATA);
  96
  97         return (Nval * accum) ^ base_entropy;
  98 }
  99
 100 static void
 101 do_host_cloak_ip(const char *inbuf, char *outbuf)
 102 {
 103         char *tptr;
 104         unsigned int accum = get_string_weighted_entropy(inbuf);
 105         char buf[HOSTLEN];
 106         int ipv6 = 0;
 107
 108         strncpy(buf, inbuf, HOSTLEN);
 109         tptr = strrchr(buf, '.');
 110
 111         if (tptr == NULL)
 112         {
 113                 tptr = strrchr(buf, ':');
 114                 ipv6 = 1;
 115         }
 116
 117         if (tptr == NULL)
 118         {
 119                 strncpy(outbuf, inbuf, HOSTLEN);
 120                 return;
 121         }
 122
 123         *tptr++ = '\0';
 124
 125         if(ipv6)
 126         {
 127             rb_snprintf(outbuf, HOSTLEN, "%s:%x", buf, accum);
 128         }
 129         else
 130         {
 131             rb_snprintf(outbuf, HOSTLEN, "%s.%x", buf, accum);
 132         }
 133 }
 134
 135 static void
 136 do_host_cloak_host(const char *inbuf, char *outbuf)
 137 {
 138         char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz";
 139         char *tptr;
 140         unsigned int accum = get_string_weighted_entropy(inbuf);
 141
 142         strncpy(outbuf, inbuf, HOSTLEN);
 143
 144         /* pass 1: scramble first section of hostname using base26
 145          * alphabet toasted against the weighted entropy of the string.
 146          *
 147          * numbers are not changed at this time, only letters.
 148          */
 149         for (tptr = outbuf; *tptr != '\0'; tptr++)
 150         {
 151                 if (*tptr == '.')
 152                         break;
 153
 154                 if (isdigit(*tptr) || *tptr == '-')
 155                         continue;
 156
 157                 *tptr = b26_alphabet[(*tptr * accum) % 26];
 158         }
 159
 160         /* pass 2: scramble each number in the address */
 161         for (tptr = outbuf; *tptr != '\0'; tptr++)
 162         {
 163                 if (isdigit(*tptr))
 164                 {
 165                         *tptr = 48 + ((*tptr * accum) % 10);
 166                 }
 167         }
 168 }
 169
 170 static void
 171 check_umode_change(void *vdata)
 172 {
 173         hook_data_umode_changed *data = (hook_data_umode_changed *)vdata;
 174         struct Client *source_p = data->client;
 175
 176         if (!MyClient(source_p))
 177                 return;
 178
 179         /* didn't change +h umode, we don't need to do anything */
 180         if (!((data->oldumodes ^ source_p->umodes) & user_modes['h']))
 181                 return;
 182
 183         if (source_p->umodes & user_modes['h'])
 184         {
 185                 if (IsIPSpoof(source_p) || source_p->localClient->mangledhost == NULL || (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost)))
 186                 {
 187                         source_p->umodes &= ~user_modes['h'];
 188                         return;
 189                 }
 190                 if (strcmp(source_p->host, source_p->localClient->mangledhost))
 191                 {
 192                         distribute_hostchange(source_p, source_p->localClient->mangledhost);
 193                 }
 194                 else /* not really nice, but we need to send this numeric here */
 195                         sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
 196                                 source_p->host);
 197         }
 198         else if (!(source_p->umodes & user_modes['h']))
 199         {
 200                 if (source_p->localClient->mangledhost != NULL &&
 201                                 !strcmp(source_p->host, source_p->localClient->mangledhost))
 202                 {
 203                         distribute_hostchange(source_p, source_p->orighost);
 204                 }
 205         }
 206 }
 207
 208 static void
 209 check_new_user(void *vdata)
 210 {
 211         struct Client *source_p = (void *)vdata;
 212
 213         if (IsIPSpoof(source_p))
 214         {
 215                 source_p->umodes &= ~user_modes['h'];
 216                 return;
 217         }
 218         source_p->localClient->mangledhost = rb_malloc(HOSTLEN);
 219         if (!irccmp(source_p->orighost, source_p->sockhost))
 220                 do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost);
 221         else
 222                 do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost);
 223         if (IsDynSpoof(source_p))
 224                 source_p->umodes &= ~user_modes['h'];
 225         if (source_p->umodes & user_modes['h'])
 226         {
 227                 rb_strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host));
 228                 if (irccmp(source_p->host, source_p->orighost))
 229                         SetDynSpoof(source_p);
 230         }
 231 }