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