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 /* if you're modifying this module, you'll probably to change this */
  14 #define KEY 0x13748cfa
  15
  16 static int
  17 _modinit(void)
  18 {
  19         /* add the usermode to the available slot */
  20         user_modes['h'] = find_umode_slot();
  21         construct_umodebuf();
  22
  23         return 0;
  24 }
  25
  26 static void
  27 _moddeinit(void)
  28 {
  29         /* disable the umode and remove it from the available list */
  30         user_modes['h'] = 0;
  31         construct_umodebuf();
  32 }
  33
  34 static void check_umode_change(void *data);
  35 static void check_new_user(void *data);
  36 mapi_hfn_list_av1 ip_cloaking_hfnlist[] = {
  37         { "umode_changed", (hookfn) check_umode_change },
  38         { "new_local_user", (hookfn) check_new_user },
  39         { NULL, NULL }
  40 };
  41
  42 DECLARE_MODULE_AV1(ip_cloaking, _modinit, _moddeinit, NULL, NULL,
  43                         ip_cloaking_hfnlist, NULL);
  44
  45 static void
  46 distribute_hostchange(struct Client *client_p, char *newhost)
  47 {
  48         if (newhost != client_p->orighost)
  49                 sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
  50                         newhost);
  51         else
  52                 sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :hostname reset",
  53                         newhost);
  54
  55         sendto_server(NULL, NULL,
  56                 CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s",
  57                 use_id(&me), use_id(client_p), newhost);
  58         sendto_server(NULL, NULL,
  59                 CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s",
  60                 use_id(&me), use_id(client_p), newhost);
  61
  62         change_nick_user_host(client_p, client_p->name, client_p->username, newhost, 0, "Changing host");
  63
  64         if (newhost != client_p->orighost)
  65                 SetDynSpoof(client_p);
  66         else
  67                 ClearDynSpoof(client_p);
  68 }
  69
  70 #define Nval 0x8c3a48ac
  71 #define HOSTLEN 63
  72 #define INITDATA "98fwqefnoiqefv03f423t34gbv3vb89tg432t3b8" /* change this */
  73
  74 static inline unsigned int
  75 get_string_entropy(const char *inbuf)
  76 {
  77         unsigned int accum = 1;
  78
  79         while(*inbuf != '\0')
  80                 accum += *inbuf++;
  81
  82         return accum;
  83 }
  84
  85 /* calls get_string_entropy() and toasts it against INITDATA */
  86 static inline unsigned int
  87 get_string_weighted_entropy(const char *inbuf)
  88 {
  89         static int base_entropy = 0;
  90         unsigned int accum = get_string_entropy(inbuf);
  91
  92         /* initialize the algorithm if it is not yet ready */
  93         if (base_entropy == 0)
  94                 base_entropy = get_string_entropy(INITDATA);
  95
  96         return (Nval * accum) ^ base_entropy;
  97 }
  98
  99 static void
 100 do_host_cloak_ip(const char *inbuf, char *outbuf)
 101 {
 102         char *tptr;
 103         unsigned int accum = get_string_weighted_entropy(inbuf);
 104         char buf[HOSTLEN];
 105         int ipv6 = 0;
 106
 107         strncpy(buf, inbuf, HOSTLEN);
 108         tptr = strrchr(buf, '.');
 109
 110         if (tptr == NULL)
 111         {
 112                 tptr = strrchr(buf, ':');
 113                 ipv6 = 1;
 114         }
 115
 116         if (tptr == NULL)
 117         {
 118                 strncpy(outbuf, inbuf, HOSTLEN);
 119                 return;
 120         }
 121
 122         *tptr++ = '\0';
 123
 124         if(ipv6)
 125         {
 126             snprintf(outbuf, HOSTLEN, "%s:%x", buf, accum);
 127         }
 128         else
 129         {
 130             snprintf(outbuf, HOSTLEN, "%s.%x", buf, accum);
 131         }
 132 }
 133
 134 static void
 135 do_host_cloak_host(const char *inbuf, char *outbuf)
 136 {
 137         char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz";
 138         char *tptr;
 139         unsigned int accum = get_string_weighted_entropy(inbuf);
 140
 141         strncpy(outbuf, inbuf, HOSTLEN);
 142
 143         /* pass 1: scramble first section of hostname using base26
 144          * alphabet toasted against the weighted entropy of the string.
 145          *
 146          * numbers are not changed at this time, only letters.
 147          */
 148         for (tptr = outbuf; *tptr != '\0'; tptr++)
 149         {
 150                 if (*tptr == '.')
 151                         break;
 152
 153                 if (isdigit((unsigned char)*tptr) || *tptr == '-')
 154                         continue;
 155
 156                 *tptr = b26_alphabet[(*tptr * accum) % 26];
 157         }
 158
 159         /* pass 2: scramble each number in the address */
 160         for (tptr = outbuf; *tptr != '\0'; tptr++)
 161         {
 162                 if (isdigit((unsigned char)*tptr))
 163                 {
 164                         *tptr = 48 + ((*tptr * accum) % 10);
 165                 }
 166         }
 167 }
 168
 169 static void
 170 check_umode_change(void *vdata)
 171 {
 172         hook_data_umode_changed *data = (hook_data_umode_changed *)vdata;
 173         struct Client *source_p = data->client;
 174
 175         if (!MyClient(source_p))
 176                 return;
 177
 178         /* didn't change +h umode, we don't need to do anything */
 179         if (!((data->oldumodes ^ source_p->umodes) & user_modes['h']))
 180                 return;
 181
 182         if (source_p->umodes & user_modes['h'])
 183         {
 184                 if (IsIPSpoof(source_p) || source_p->localClient->mangledhost == NULL || (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost)))
 185                 {
 186                         source_p->umodes &= ~user_modes['h'];
 187                         return;
 188                 }
 189                 if (strcmp(source_p->host, source_p->localClient->mangledhost))
 190                 {
 191                         distribute_hostchange(source_p, source_p->localClient->mangledhost);
 192                 }
 193                 else /* not really nice, but we need to send this numeric here */
 194                         sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
 195                                 source_p->host);
 196         }
 197         else if (!(source_p->umodes & user_modes['h']))
 198         {
 199                 if (source_p->localClient->mangledhost != NULL &&
 200                                 !strcmp(source_p->host, source_p->localClient->mangledhost))
 201                 {
 202                         distribute_hostchange(source_p, source_p->orighost);
 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 }