extensions/sasl_usercloak.c

   1 #include "stdinc.h"
   2 #include "modules.h"
   3 #include "hook.h"
   4 #include "client.h"
   5 #include "ircd.h"
   6 #include "send.h"
   7 #include "hash.h"
   8 #include "s_conf.h"
   9 #include "s_user.h"
  10 #include "s_serv.h"
  11 #include "numeric.h"
  12
  13 #include <stdint.h>
  14
  15 static void check_new_user(void *data);
  16 mapi_hfn_list_av1 sasl_usercloak_hfnlist[] = {
  17         { "new_local_user", (hookfn) check_new_user },
  18         { NULL, NULL }
  19 };
  20
  21 DECLARE_MODULE_AV1(sasl_usercloak, NULL, NULL, NULL, NULL,
  22                         sasl_usercloak_hfnlist, "$Revision: 3526 $");
  23
  24 unsigned int fnv_hash_string(char *str)
  25 {
  26         unsigned int hash = 0x811c9dc5; // Magic value for 32-bit fnv1 hash initialisation.
  27         unsigned char *p = (unsigned char *)str;
  28         while (*p)
  29         {
  30                 hash += (hash<<1) + (hash<<4) + (hash<<7) + (hash<<8) + (hash<<24);
  31                 hash ^= *p++;
  32         }
  33         return hash;
  34 }
  35
  36 static void
  37 check_new_user(void *vdata)
  38 {
  39         struct Client *source_p = (void *)vdata;
  40
  41         if (!IsIPSpoof(source_p))
  42                 return;
  43
  44         if (EmptyString(source_p->user->suser))
  45                 return;
  46
  47         char *accountpart = strstr(source_p->host, "account");
  48         if (!accountpart)
  49                 return;
  50
  51         char buf[HOSTLEN];
  52         char *dst = buf;
  53
  54         strncpy(buf, source_p->host, accountpart - source_p->host);
  55         dst += accountpart - source_p->host;
  56
  57         int needhash = 0;
  58
  59         for (char *src = source_p->user->suser; *src ; src++ )
  60         {
  61                 if (dst > buf + sizeof(buf))
  62                 {
  63                         /* Doesn't fit. Warn opers and bail. */
  64                         sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
  65                                         "Couldn't fit account name part %s in hostname for %s!%s@%s",
  66                                         source_p->user->suser, source_p->name, source_p->username, source_p->host);
  67                         return;
  68                 }
  69
  70                 char c = ToLower(*src);
  71
  72                 if (IsHostChar(c))
  73                         *dst++ = c;
  74                 else
  75                         needhash = 1;
  76         }
  77
  78         if (needhash)
  79         {
  80                 if (dst > buf + sizeof(buf) - 12) /* '/x-' plus eight digit hash plus null terminator */
  81                 {
  82                         /* Doesn't fit. Warn opers and bail. */
  83                         sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
  84                                         "Couldn't fit account name part %s in hostname for %s!%s@%s",
  85                                         source_p->user->suser, source_p->name, source_p->user, source_p->host);
  86                         return;
  87                 }
  88
  89                 *dst++ = '/';
  90                 *dst++ = 'x';
  91                 *dst++ = '-';
  92
  93                 unsigned int hashval = fnv_hash_string(source_p->user->suser);
  94                 hashval %= 100000000; // eight digits only please.
  95                 snprintf(dst, 9, "%08ud", hashval);
  96         }
  97
  98         /* just in case */
  99         buf[HOSTLEN-1] = '\0';
 100
 101         change_nick_user_host(source_p, source_p->name, source_p->username, buf, 0, "Changing host");
 102 }