modules/m_challenge.c

   1 /*
   2  *  ircd-ratbox: A slightly useful ircd.
   3  *  m_challenge.c: Allows an IRC Operator to securely authenticate.
   4  *
   5  *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
   6  *  Copyright (C) 1996-2002 Hybrid Development Team
   7  *  Copyright (C) 2002-2005 ircd-ratbox development team
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; either version 2 of the License, or
  12  *  (at your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to the Free Software
  21  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
  22  *  USA
  23  */
  24
  25 #include "stdinc.h"
  26
  27 #ifdef HAVE_LIBCRYPTO
  28 #include <openssl/pem.h>
  29 #include <openssl/rand.h>
  30 #include <openssl/rsa.h>
  31 #include <openssl/md5.h>
  32 #include <openssl/bn.h>
  33 #include <openssl/evp.h>
  34 #include <openssl/err.h>
  35 #endif
  36
  37 #include "client.h"
  38 #include "ircd.h"
  39 #include "modules.h"
  40 #include "numeric.h"
  41 #include "send.h"
  42 #include "s_conf.h"
  43 #include "msg.h"
  44 #include "parse.h"
  45 #include "match.h"
  46 #include "logger.h"
  47 #include "s_user.h"
  48 #include "cache.h"
  49 #include "s_newconf.h"
  50
  51 #define CHALLENGE_WIDTH BUFSIZE - (NICKLEN + HOSTLEN + 12)
  52 #define CHALLENGE_EXPIRES       180     /* 180 seconds should be more than long enough */
  53 #define CHALLENGE_SECRET_LENGTH 128     /* how long our challenge secret should be */
  54
  55 #ifndef HAVE_LIBCRYPTO
  56 /* Maybe this should be an error or something?-davidt */
  57 /* now it is    -larne  */
  58 static int      challenge_load(void)
  59 {
  60 #ifndef STATIC_MODULES
  61         sendto_realops_snomask(SNO_GENERAL, L_ALL,
  62                 "Challenge module not loaded because OpenSSL is not available.");
  63         ilog(L_MAIN, "Challenge module not loaded because OpenSSL is not available.");
  64         return -1;
  65 #else
  66         return 0;
  67 #endif
  68 }
  69
  70 static const char challenge_desc[] = "Does nothing as OpenSSL was not enabled.";
  71
  72 DECLARE_MODULE_AV2(challenge, challenge_load, NULL, NULL, NULL, NULL, NULL, NULL, challenge_desc);
  73 #else
  74
  75 static int m_challenge(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
  76
  77 /* We have openssl support, so include /CHALLENGE */
  78 struct Message challenge_msgtab = {
  79         "CHALLENGE", 0, 0, 0, 0,
  80         {mg_unreg, {m_challenge, 2}, mg_ignore, mg_ignore, mg_ignore, {m_challenge, 2}}
  81 };
  82
  83 mapi_clist_av1 challenge_clist[] = { &challenge_msgtab, NULL };
  84
  85 static const char challenge_desc[] =
  86         "Provides the challenge-response facility used for becoming an IRC operator";
  87
  88
  89 DECLARE_MODULE_AV2(challenge, NULL, NULL, challenge_clist, NULL, NULL, NULL, NULL, challenge_desc);
  90
  91 static int generate_challenge(char **r_challenge, char **r_response, RSA * key);
  92
  93 static void
  94 cleanup_challenge(struct Client *target_p)
  95 {
  96         if(target_p->localClient == NULL)
  97                 return;
  98
  99         rb_free(target_p->localClient->challenge);
 100         rb_free(target_p->localClient->opername);
 101         target_p->localClient->challenge = NULL;
 102         target_p->localClient->opername = NULL;
 103         target_p->localClient->chal_time = 0;
 104 }
 105
 106 /*
 107  * m_challenge - generate RSA challenge for wouldbe oper
 108  * parv[1] = operator to challenge for, or +response
 109  */
 110 static int
 111 m_challenge(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
 112 {
 113         struct oper_conf *oper_p;
 114         char *challenge = NULL; /* to placate gcc */
 115         char chal_line[CHALLENGE_WIDTH];
 116         unsigned char *b_response;
 117         size_t cnt;
 118         int len = 0;
 119
 120         /* if theyre an oper, reprint oper motd and ignore */
 121         if(IsOper(source_p))
 122         {
 123                 sendto_one(source_p, form_str(RPL_YOUREOPER), me.name, source_p->name);
 124                 send_oper_motd(source_p);
 125                 return 0;
 126         }
 127
 128         if(*parv[1] == '+')
 129         {
 130                 /* Ignore it if we aren't expecting this... -A1kmm */
 131                 if(!source_p->localClient->challenge)
 132                         return 0;
 133
 134                 if((rb_current_time() - source_p->localClient->chal_time) > CHALLENGE_EXPIRES)
 135                 {
 136                         sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
 137                         ilog(L_FOPER, "EXPIRED CHALLENGE (%s) by (%s!%s@%s) (%s)",
 138                              source_p->localClient->opername, source_p->name,
 139                              source_p->username, source_p->host, source_p->sockhost);
 140
 141                         if(ConfigFileEntry.failed_oper_notice)
 142                                 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 143                                                      "Expired CHALLENGE attempt by %s (%s@%s)",
 144                                                      source_p->name, source_p->username,
 145                                                      source_p->host);
 146                         cleanup_challenge(source_p);
 147                         return 0;
 148                 }
 149
 150                 parv[1]++;
 151                 b_response = rb_base64_decode((const unsigned char *)parv[1], strlen(parv[1]), &len);
 152
 153                 if(len != SHA_DIGEST_LENGTH ||
 154                    memcmp(source_p->localClient->challenge, b_response, SHA_DIGEST_LENGTH))
 155                 {
 156                         sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
 157                         ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s)",
 158                              source_p->localClient->opername, source_p->name,
 159                              source_p->username, source_p->host, source_p->sockhost);
 160
 161                         if(ConfigFileEntry.failed_oper_notice)
 162                                 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 163                                                      "Failed CHALLENGE attempt by %s (%s@%s)",
 164                                                      source_p->name, source_p->username,
 165                                                      source_p->host);
 166
 167                         rb_free(b_response);
 168                         cleanup_challenge(source_p);
 169                         return 0;
 170                 }
 171
 172                 rb_free(b_response);
 173
 174                 oper_p = find_oper_conf(source_p->username, source_p->orighost,
 175                                         source_p->sockhost,
 176                                         source_p->localClient->opername);
 177
 178                 if(oper_p == NULL)
 179                 {
 180                         sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 181                         ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
 182                              source_p->localClient->opername, source_p->name,
 183                              source_p->username, source_p->host,
 184                              source_p->sockhost);
 185
 186                         if(ConfigFileEntry.failed_oper_notice)
 187                                 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 188                                                      "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
 189                                                      source_p->name, source_p->username,
 190                                                      source_p->host);
 191                         return 0;
 192                 }
 193
 194                 cleanup_challenge(source_p);
 195
 196                 oper_up(source_p, oper_p);
 197
 198                 ilog(L_OPERED, "OPER %s by %s!%s@%s (%s)",
 199                      source_p->localClient->opername, source_p->name,
 200                      source_p->username, source_p->host, source_p->sockhost);
 201                 return 0;
 202         }
 203
 204         cleanup_challenge(source_p);
 205
 206         oper_p = find_oper_conf(source_p->username, source_p->orighost,
 207                                 source_p->sockhost, parv[1]);
 208
 209         if(oper_p == NULL)
 210         {
 211                 sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 212                 ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
 213                      parv[1], source_p->name,
 214                      source_p->username, source_p->host, source_p->sockhost);
 215
 216                 if(ConfigFileEntry.failed_oper_notice)
 217                         sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 218                                              "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
 219                                              source_p->name, source_p->username, source_p->host);
 220                 return 0;
 221         }
 222
 223         if(!oper_p->rsa_pubkey)
 224         {
 225                 sendto_one_notice(source_p, ":I'm sorry, PK authentication is not enabled for your oper{} block.");
 226                 return 0;
 227         }
 228
 229         if(IsOperConfNeedSSL(oper_p) && !IsSSLClient(source_p))
 230         {
 231                 sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 232                 ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s) -- requires SSL/TLS",
 233                      parv[1], source_p->name, source_p->username, source_p->host,
 234                      source_p->sockhost);
 235
 236                 if(ConfigFileEntry.failed_oper_notice)
 237                 {
 238                         sendto_realops_snomask(SNO_GENERAL, L_ALL,
 239                                              "Failed CHALLENGE attempt - missing SSL/TLS by %s (%s@%s)",
 240                                              source_p->name, source_p->username, source_p->host);
 241                 }
 242                 return 0;
 243         }
 244
 245         if (oper_p->certfp != NULL)
 246         {
 247                 if (source_p->certfp == NULL || strcasecmp(source_p->certfp, oper_p->certfp))
 248                 {
 249                         sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 250                         ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s) -- client certificate fingerprint mismatch",
 251                              parv[1], source_p->name,
 252                              source_p->username, source_p->host, source_p->sockhost);
 253
 254                         if(ConfigFileEntry.failed_oper_notice)
 255                         {
 256                                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 257                                                      "Failed OPER attempt - client certificate fingerprint mismatch by %s (%s@%s)",
 258                                                      source_p->name, source_p->username, source_p->host);
 259                         }
 260                         return 0;
 261                 }
 262         }
 263
 264         if(!generate_challenge(&challenge, &(source_p->localClient->challenge), oper_p->rsa_pubkey))
 265         {
 266                 char *chal = challenge;
 267                 source_p->localClient->chal_time = rb_current_time();
 268                 for(;;)
 269                 {
 270                         cnt = rb_strlcpy(chal_line, chal, CHALLENGE_WIDTH);
 271                         sendto_one(source_p, form_str(RPL_RSACHALLENGE2), me.name, source_p->name, chal_line);
 272                         if(cnt > CHALLENGE_WIDTH)
 273                                 chal += CHALLENGE_WIDTH - 1;
 274                         else
 275                                 break;
 276
 277                 }
 278                 sendto_one(source_p, form_str(RPL_ENDOFRSACHALLENGE2),
 279                            me.name, source_p->name);
 280                 rb_free(challenge);
 281                 source_p->localClient->opername = rb_strdup(oper_p->name);
 282         }
 283         else
 284                 sendto_one_notice(source_p, ":Failed to generate challenge.");
 285
 286         return 0;
 287 }
 288
 289 static int
 290 generate_challenge(char **r_challenge, char **r_response, RSA * rsa)
 291 {
 292         SHA_CTX ctx;
 293         unsigned char secret[CHALLENGE_SECRET_LENGTH], *tmp;
 294         unsigned long length;
 295         unsigned long e = 0;
 296         unsigned long cnt = 0;
 297         int ret;
 298
 299         if(!rsa)
 300                 return -1;
 301         if(rb_get_random(secret, CHALLENGE_SECRET_LENGTH))
 302         {
 303                 SHA1_Init(&ctx);
 304                 SHA1_Update(&ctx, (uint8_t *)secret, CHALLENGE_SECRET_LENGTH);
 305                 *r_response = malloc(SHA_DIGEST_LENGTH);
 306                 SHA1_Final((uint8_t *)*r_response, &ctx);
 307
 308                 length = RSA_size(rsa);
 309                 tmp = rb_malloc(length);
 310                 ret = RSA_public_encrypt(CHALLENGE_SECRET_LENGTH, secret, tmp, rsa, RSA_PKCS1_OAEP_PADDING);
 311
 312                 if(ret >= 0)
 313                 {
 314                         *r_challenge = (char *)rb_base64_encode(tmp, ret);
 315                         rb_free(tmp);
 316                         return 0;
 317                 }
 318
 319                 rb_free(tmp);
 320                 rb_free(*r_response);
 321                 *r_response = NULL;
 322         }
 323
 324         ERR_load_crypto_strings();
 325         while ((cnt < 100) && (e = ERR_get_error()))
 326         {
 327                 ilog(L_MAIN, "SSL error: %s", ERR_error_string(e, 0));
 328                 cnt++;
 329         }
 330
 331         return (-1);
 332 }
 333
 334 #endif /* HAVE_LIBCRYPTO */