extensions/ip_cloaking_3.0.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 "s_conf.h"
   9 #include "s_user.h"
  10 #include "s_serv.h"
  11 #include "numeric.h"
  12
  13 static const char ip_cloaking_desc[] = "The old IP cloaking mechanism version 3.0";
  14
  15 /* if you're modifying this module, you'll probably want to change this */
  16 #define KEY 0x13748cfa
  17
  18 static int
  19 _modinit(void)
  20 {
  21         /* add the usermode to the available slot */
  22         user_modes['h'] = find_umode_slot();
  23         construct_umodebuf();
  24
  25         return 0;
  26 }
  27
  28 static void
  29 _moddeinit(void)
  30 {
  31         /* disable the umode and remove it from the available list */
  32         user_modes['h'] = 0;
  33         construct_umodebuf();
  34 }
  35
  36 static void check_umode_change(void *data);
  37 static void check_new_user(void *data);
  38 mapi_hfn_list_av1 ip_cloaking_hfnlist[] = {
  39         { "umode_changed", check_umode_change },
  40         { "new_local_user", check_new_user },
  41         { NULL, NULL }
  42 };
  43
  44 DECLARE_MODULE_AV2(ip_cloaking, _modinit, _moddeinit, NULL, NULL,
  45         ip_cloaking_hfnlist, NULL, NULL, ip_cloaking_desc);
  46
  47 static void
  48 distribute_hostchange(struct Client *client_p, char *newhost)
  49 {
  50         if (newhost != client_p->orighost)
  51                 sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
  52                         newhost);
  53         else
  54                 sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :hostname reset",
  55                         newhost);
  56
  57         sendto_server(NULL, NULL,
  58                 CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s",
  59                 use_id(&me), use_id(client_p), newhost);
  60         sendto_server(NULL, NULL,
  61                 CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s",
  62                 use_id(&me), use_id(client_p), newhost);
  63
  64         change_nick_user_host(client_p, client_p->name, client_p->username, newhost, 0, "Changing host");
  65
  66         if (newhost != client_p->orighost)
  67                 SetDynSpoof(client_p);
  68         else
  69                 ClearDynSpoof(client_p);
  70 }
  71
  72 #define Nval 0x8c3a48ac
  73 #define HOSTLEN 63
  74 #define INITDATA "98fwqefnoiqefv03f423t34gbv3vb89tg432t3b8" /* change this */
  75
  76 static inline unsigned int
  77 get_string_entropy(const char *inbuf)
  78 {
  79         unsigned int accum = 1;
  80
  81         while(*inbuf != '\0')
  82                 accum += *inbuf++;
  83
  84         return accum;
  85 }
  86
  87 /* calls get_string_entropy() and toasts it against INITDATA */
  88 static inline unsigned int
  89 get_string_weighted_entropy(const char *inbuf)
  90 {
  91         static int base_entropy = 0;
  92         unsigned int accum = get_string_entropy(inbuf);
  93
  94         /* initialize the algorithm if it is not yet ready */
  95         if (base_entropy == 0)
  96                 base_entropy = get_string_entropy(INITDATA);
  97
  98         return (Nval * accum) ^ base_entropy;
  99 }
 100
 101 static void
 102 do_host_cloak_ip(const char *inbuf, char *outbuf)
 103 {
 104         char *tptr;
 105         unsigned int accum = get_string_weighted_entropy(inbuf);
 106         char buf[HOSTLEN + 1] = { 0 };
 107         int ipv6 = 0;
 108
 109         strncpy(buf, inbuf, HOSTLEN);
 110         tptr = strrchr(buf, '.');
 111
 112         if (tptr == NULL)
 113         {
 114                 tptr = strrchr(buf, ':');
 115                 ipv6 = 1;
 116         }
 117
 118         if (tptr == NULL)
 119         {
 120                 strncpy(outbuf, inbuf, HOSTLEN);
 121                 return;
 122         }
 123
 124         *tptr++ = '\0';
 125
 126         if(ipv6)
 127         {
 128             snprintf(outbuf, HOSTLEN, "%.60s:%x", buf, accum);
 129         }
 130         else
 131         {
 132             snprintf(outbuf, HOSTLEN, "%.60s.%x", buf, accum);
 133         }
 134 }
 135
 136 static void
 137 do_host_cloak_host(const char *inbuf, char *outbuf)
 138 {
 139         char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz";
 140         char *tptr;
 141         unsigned int accum = get_string_weighted_entropy(inbuf);
 142
 143         strncpy(outbuf, inbuf, HOSTLEN);
 144
 145         /* pass 1: scramble first section of hostname using base26
 146          * alphabet toasted against the weighted entropy of the string.
 147          *
 148          * numbers are not changed at this time, only letters.
 149          */
 150         for (tptr = outbuf; *tptr != '\0'; tptr++)
 151         {
 152                 if (*tptr == '.')
 153                         break;
 154
 155                 if (isdigit((unsigned char)*tptr) || *tptr == '-')
 156                         continue;
 157
 158                 *tptr = b26_alphabet[(*tptr * accum) % 26];
 159         }
 160
 161         /* pass 2: scramble each number in the address */
 162         for (tptr = outbuf; *tptr != '\0'; tptr++)
 163         {
 164                 if (isdigit((unsigned char)*tptr))
 165                 {
 166                         *tptr = 48 + ((*tptr * accum) % 10);
 167                 }
 168         }
 169 }
 170
 171 static void
 172 check_umode_change(void *vdata)
 173 {
 174         hook_data_umode_changed *data = (hook_data_umode_changed *)vdata;
 175         struct Client *source_p = data->client;
 176
 177         if (!MyClient(source_p))
 178                 return;
 179
 180         /* didn't change +h umode, we don't need to do anything */
 181         if (!((data->oldumodes ^ source_p->umodes) & user_modes['h']))
 182                 return;
 183
 184         if (source_p->umodes & user_modes['h'])
 185         {
 186                 if (IsIPSpoof(source_p) || source_p->localClient->mangledhost == NULL || (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost)))
 187                 {
 188                         source_p->umodes &= ~user_modes['h'];
 189                         return;
 190                 }
 191                 if (strcmp(source_p->host, source_p->localClient->mangledhost))
 192                 {
 193                         distribute_hostchange(source_p, source_p->localClient->mangledhost);
 194                 }
 195                 else /* not really nice, but we need to send this numeric here */
 196                         sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
 197                                 source_p->host);
 198         }
 199         else if (!(source_p->umodes & user_modes['h']))
 200         {
 201                 if (source_p->localClient->mangledhost != NULL &&
 202                                 !strcmp(source_p->host, source_p->localClient->mangledhost))
 203                 {
 204                         distribute_hostchange(source_p, source_p->orighost);
 205                 }
 206         }
 207 }
 208
 209 static void
 210 check_new_user(void *vdata)
 211 {
 212         struct Client *source_p = (void *)vdata;
 213
 214         if (IsIPSpoof(source_p))
 215         {
 216                 source_p->umodes &= ~user_modes['h'];
 217                 return;
 218         }
 219         source_p->localClient->mangledhost = rb_malloc(HOSTLEN + 1);
 220         if (!irccmp(source_p->orighost, source_p->sockhost))
 221                 do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost);
 222         else
 223                 do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost);
 224         if (IsDynSpoof(source_p))
 225                 source_p->umodes &= ~user_modes['h'];
 226         if (source_p->umodes & user_modes['h'])
 227         {
 228                 rb_strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host));
 229                 if (irccmp(source_p->host, source_p->orighost))
 230                         SetDynSpoof(source_p);
 231         }
 232 }