extensions/ip_cloaking.c

   1 /* $Id: ip_cloaking.c 3524 2007-07-06 07:54:54Z 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 "tools.h"
  13 #include "numeric.h"
  14
  15 /* if you're modifying this module, you'll probably 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", (hookfn) check_umode_change },
  40         { "new_local_user", (hookfn) check_new_user },
  41         { NULL, NULL }
  42 };
  43
  44 DECLARE_MODULE_AV1(ip_cloaking, _modinit, _moddeinit, NULL, NULL,
  45                         ip_cloaking_hfnlist, "$Revision: 3524 $");
  46
  47 static void
  48 distribute_hostchange(struct Client *client)
  49 {
  50         if (irccmp(client->host, client->orighost))
  51                 sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :is now your hidden host",
  52                         client->host);
  53         else
  54                 sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :hostname reset",
  55                         client->host);
  56
  57         sendto_server(NULL, NULL,
  58                 CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s",
  59                 use_id(&me), use_id(client), client->host);
  60         sendto_server(NULL, NULL,
  61                 CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s",
  62                 use_id(&me), use_id(client), client->host);
  63         sendto_server(NULL, NULL,
  64                 NOCAPS, CAP_TS6, ":%s ENCAP * CHGHOST %s :%s",
  65                 me.name, client->name, client->host);
  66         if (irccmp(client->host, client->orighost))
  67                 SetDynSpoof(client);
  68         else
  69                 ClearDynSpoof(client);
  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];
 107
 108         strncpy(buf, inbuf, HOSTLEN);
 109         tptr = strrchr(buf, '.');
 110
 111         if (tptr == NULL)
 112                 return;
 113
 114         *tptr++ = '\0';
 115
 116         snprintf(outbuf, HOSTLEN, "%s.%x", buf, accum);
 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         unsigned int accum = get_string_weighted_entropy(inbuf);
 125
 126         strncpy(outbuf, inbuf, HOSTLEN);
 127
 128         /* pass 1: scramble first section of hostname using base26
 129          * alphabet toasted against the weighted entropy 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
 144         /* pass 2: scramble each number in the address */
 145         for (tptr = outbuf; *tptr != '\0'; tptr++)
 146         {
 147                 if (isdigit(*tptr))
 148                 {
 149                         *tptr = 48 + ((*tptr * accum) % 10);
 150                 }
 151         }
 152 }
 153
 154 static void
 155 check_umode_change(void *vdata)
 156 {
 157         hook_data_umode_changed *data = (hook_data_umode_changed *)vdata;
 158         struct Client *source_p = data->client;
 159
 160         if (!MyClient(source_p))
 161                 return;
 162
 163         /* didn't change +h umode, we don't need to do anything */
 164         if (!((data->oldumodes ^ source_p->umodes) & user_modes['h']))
 165                 return;
 166
 167         if (source_p->umodes & user_modes['h'])
 168         {
 169                 if (IsIPSpoof(source_p) || source_p->localClient->mangledhost == NULL || (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost)))
 170                 {
 171                         source_p->umodes &= ~user_modes['h'];
 172                         return;
 173                 }
 174                 if (strcmp(source_p->host, source_p->localClient->mangledhost))
 175                 {
 176                         strlcpy(source_p->host, source_p->localClient->mangledhost, HOSTLEN);
 177                         distribute_hostchange(source_p);
 178                 }
 179                 else /* not really nice, but we need to send this numeric here */
 180                         sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
 181                                 source_p->host);
 182         }
 183         else if (!(source_p->umodes & user_modes['h']))
 184         {
 185                 if (source_p->localClient->mangledhost != NULL &&
 186                                 !strcmp(source_p->host, source_p->localClient->mangledhost))
 187                 {
 188                         strlcpy(source_p->host, source_p->orighost, HOSTLEN);
 189                         distribute_hostchange(source_p);
 190                 }
 191         }
 192 }
 193
 194 static void
 195 check_new_user(void *vdata)
 196 {
 197         struct Client *source_p = (void *)vdata;
 198
 199         if (IsIPSpoof(source_p))
 200         {
 201                 source_p->umodes &= ~user_modes['h'];
 202                 return;
 203         }
 204         source_p->localClient->mangledhost = MyMalloc(HOSTLEN);
 205         if (!irccmp(source_p->orighost, source_p->sockhost))
 206                 do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost);
 207         else
 208                 do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost);
 209         if (IsDynSpoof(source_p))
 210                 source_p->umodes &= ~user_modes['h'];
 211         if (source_p->umodes & user_modes['h'])
 212         {
 213                 strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host));
 214                 if (irccmp(source_p->host, source_p->orighost))
 215                         SetDynSpoof(source_p);
 216         }
 217 }