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  *  $Id: m_challenge.c 3161 2007-01-25 07:23:01Z nenolod $
  25  */
  26
  27 #include "stdinc.h"
  28
  29 #ifdef HAVE_LIBCRYPTO
  30 #include <openssl/pem.h>
  31 #include <openssl/rand.h>
  32 #include <openssl/rsa.h>
  33 #include <openssl/md5.h>
  34 #include <openssl/bn.h>
  35 #include <openssl/evp.h>
  36 #include <openssl/err.h>
  37 #endif
  38
  39 #include "client.h"
  40 #include "ircd.h"
  41 #include "modules.h"
  42 #include "numeric.h"
  43 #include "send.h"
  44 #include "s_conf.h"
  45 #include "msg.h"
  46 #include "parse.h"
  47 #include "match.h"
  48 #include "logger.h"
  49 #include "s_user.h"
  50 #include "cache.h"
  51 #include "s_newconf.h"
  52
  53 #define CHALLENGE_WIDTH BUFSIZE - (NICKLEN + HOSTLEN + 12)
  54 #define CHALLENGE_EXPIRES       180     /* 180 seconds should be more than long enough */
  55 #define CHALLENGE_SECRET_LENGTH 128     /* how long our challenge secret should be */
  56
  57 #ifndef HAVE_LIBCRYPTO
  58 /* Maybe this should be an error or something?-davidt */
  59 /* now it is    -larne  */
  60 static int      challenge_load(void)
  61 {
  62 #ifndef STATIC_MODULES
  63         sendto_realops_snomask(SNO_GENERAL, L_ALL,
  64                 "Challenge module not loaded because OpenSSL is not available.");
  65         ilog(L_MAIN, "Challenge module not loaded because OpenSSL is not available.");
  66         return -1;
  67 #else
  68         return 0;
  69 #endif
  70 }
  71
  72 DECLARE_MODULE_AV1(challenge, challenge_load, NULL, NULL, NULL, NULL, "$Revision: 3161 $");
  73 #else
  74
  75 static int m_challenge(struct Client *, struct Client *, int, const char **);
  76
  77 /* We have openssl support, so include /CHALLENGE */
  78 struct Message challenge_msgtab = {
  79         "CHALLENGE", 0, 0, 0, MFLG_SLOW,
  80         {mg_unreg, {m_challenge, 2}, mg_ignore, mg_ignore, mg_ignore, {m_challenge, 2}}
  81 };
  82
  83 mapi_clist_av1 challenge_clist[] = { &challenge_msgtab, NULL };
  84 DECLARE_MODULE_AV1(challenge, NULL, NULL, challenge_clist, NULL, NULL, "$Revision: 3161 $");
  85
  86 static int generate_challenge(char **r_challenge, char **r_response, RSA * key);
  87
  88 static void
  89 cleanup_challenge(struct Client *target_p)
  90 {
  91         if(target_p->localClient == NULL)
  92                 return;
  93
  94         rb_free(target_p->localClient->challenge);
  95         rb_free(target_p->localClient->opername);
  96         target_p->localClient->challenge = NULL;
  97         target_p->localClient->opername = NULL;
  98         target_p->localClient->chal_time = 0;
  99 }
 100
 101 /*
 102  * m_challenge - generate RSA challenge for wouldbe oper
 103  * parv[1] = operator to challenge for, or +response
 104  *
 105  */
 106 static int
 107 m_challenge(struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
 108 {
 109         struct oper_conf *oper_p;
 110         char *challenge = NULL; /* to placate gcc */
 111         char chal_line[CHALLENGE_WIDTH];
 112         unsigned char *b_response;
 113         size_t cnt;
 114         int len = 0;
 115
 116         /* if theyre an oper, reprint oper motd and ignore */
 117         if(IsOper(source_p))
 118         {
 119                 sendto_one(source_p, form_str(RPL_YOUREOPER), me.name, source_p->name);
 120                 send_oper_motd(source_p);
 121                 return 0;
 122         }
 123
 124         if(*parv[1] == '+')
 125         {
 126                 /* Ignore it if we aren't expecting this... -A1kmm */
 127                 if(!source_p->localClient->challenge)
 128                         return 0;
 129
 130                 if((rb_current_time() - source_p->localClient->chal_time) > CHALLENGE_EXPIRES)
 131                 {
 132                         sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
 133                         ilog(L_FOPER, "EXPIRED CHALLENGE (%s) by (%s!%s@%s) (%s)",
 134                              source_p->localClient->opername, source_p->name,
 135                              source_p->username, source_p->host, source_p->sockhost);
 136
 137                         if(ConfigFileEntry.failed_oper_notice)
 138                                 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 139                                                      "Expired CHALLENGE attempt by %s (%s@%s)",
 140                                                      source_p->name, source_p->username,
 141                                                      source_p->host);
 142                         cleanup_challenge(source_p);
 143                         return 0;
 144                 }
 145
 146                 b_response = rb_base64_decode((const unsigned char *)++parv[1], strlen(parv[1]), &len);
 147
 148                 if(len != SHA_DIGEST_LENGTH ||
 149                    memcmp(source_p->localClient->challenge, b_response, SHA_DIGEST_LENGTH))
 150                 {
 151                         sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
 152                         ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s)",
 153                              source_p->localClient->opername, source_p->name,
 154                              source_p->username, source_p->host, source_p->sockhost);
 155
 156                         if(ConfigFileEntry.failed_oper_notice)
 157                                 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 158                                                      "Failed CHALLENGE attempt by %s (%s@%s)",
 159                                                      source_p->name, source_p->username,
 160                                                      source_p->host);
 161
 162                         rb_free(b_response);
 163                         cleanup_challenge(source_p);
 164                         return 0;
 165                 }
 166
 167                 rb_free(b_response);
 168
 169                 oper_p = find_oper_conf(source_p->username, source_p->orighost,
 170                                         source_p->sockhost,
 171                                         source_p->localClient->opername);
 172
 173                 if(oper_p == NULL)
 174                 {
 175                         sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 176                         ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
 177                              source_p->localClient->opername, source_p->name,
 178                              source_p->username, source_p->host,
 179                              source_p->sockhost);
 180
 181                         if(ConfigFileEntry.failed_oper_notice)
 182                                 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 183                                                      "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
 184                                                      source_p->name, source_p->username,
 185                                                      source_p->host);
 186                         return 0;
 187                 }
 188
 189                 cleanup_challenge(source_p);
 190
 191                 oper_up(source_p, oper_p);
 192
 193                 ilog(L_OPERED, "OPER %s by %s!%s@%s (%s)",
 194                      source_p->localClient->opername, source_p->name,
 195                      source_p->username, source_p->host, source_p->sockhost);
 196                 return 0;
 197         }
 198
 199         cleanup_challenge(source_p);
 200
 201         oper_p = find_oper_conf(source_p->username, source_p->orighost,
 202                                 source_p->sockhost, parv[1]);
 203
 204         if(oper_p == NULL)
 205         {
 206                 sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 207                 ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
 208                      parv[1], source_p->name,
 209                      source_p->username, source_p->host, source_p->sockhost);
 210
 211                 if(ConfigFileEntry.failed_oper_notice)
 212                         sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 213                                              "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
 214                                              source_p->name, source_p->username, source_p->host);
 215                 return 0;
 216         }
 217
 218         if(!oper_p->rsa_pubkey)
 219         {
 220                 sendto_one_notice(source_p, ":I'm sorry, PK authentication is not enabled for your oper{} block.");
 221                 return 0;
 222         }
 223
 224         if(IsOperConfNeedSSL(oper_p) && !IsSSLClient(source_p))
 225         {
 226                 sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 227                 ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s) -- requires SSL/TLS",
 228                      parv[1], source_p->name, source_p->username, source_p->host,
 229                      source_p->sockhost);
 230
 231                 if(ConfigFileEntry.failed_oper_notice)
 232                 {
 233                         sendto_realops_snomask(SNO_GENERAL, L_ALL,
 234                                              "Failed CHALLENGE attempt - missing SSL/TLS by %s (%s@%s)",
 235                                              source_p->name, source_p->username, source_p->host);
 236                 }
 237                 return 0;
 238         }
 239
 240         if (oper_p->certfp != NULL)
 241         {
 242                 if (source_p->certfp == NULL || strcasecmp(source_p->certfp, oper_p->certfp))
 243                 {
 244                         sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 245                         ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s) -- client certificate fingerprint mismatch",
 246                              parv[1], source_p->name,
 247                              source_p->username, source_p->host, source_p->sockhost);
 248
 249                         if(ConfigFileEntry.failed_oper_notice)
 250                         {
 251                                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 252                                                      "Failed OPER attempt - client certificate fingerprint mismatch by %s (%s@%s)",
 253                                                      source_p->name, source_p->username, source_p->host);
 254                         }
 255                         return 0;
 256                 }
 257         }
 258
 259         if(!generate_challenge(&challenge, &(source_p->localClient->challenge), oper_p->rsa_pubkey))
 260         {
 261                 char *chal = challenge;
 262                 source_p->localClient->chal_time = rb_current_time();
 263                 for(;;)
 264                 {
 265                         cnt = rb_strlcpy(chal_line, chal, CHALLENGE_WIDTH);
 266                         sendto_one(source_p, form_str(RPL_RSACHALLENGE2), me.name, source_p->name, chal_line);
 267                         if(cnt > CHALLENGE_WIDTH)
 268                                 chal += CHALLENGE_WIDTH - 1;
 269                         else
 270                                 break;
 271
 272                 }
 273                 sendto_one(source_p, form_str(RPL_ENDOFRSACHALLENGE2),
 274                            me.name, source_p->name);
 275                 rb_free(challenge);
 276                 source_p->localClient->opername = rb_strdup(oper_p->name);
 277         }
 278         else
 279                 sendto_one_notice(source_p, ":Failed to generate challenge.");
 280
 281         return 0;
 282 }
 283
 284 static int
 285 generate_challenge(char **r_challenge, char **r_response, RSA * rsa)
 286 {
 287         SHA_CTX ctx;
 288         unsigned char secret[CHALLENGE_SECRET_LENGTH], *tmp;
 289         unsigned long length;
 290         unsigned long e = 0;
 291         unsigned long cnt = 0;
 292         int ret;
 293
 294         if(!rsa)
 295                 return -1;
 296         if(rb_get_random(secret, CHALLENGE_SECRET_LENGTH))
 297         {
 298                 SHA1_Init(&ctx);
 299                 SHA1_Update(&ctx, (uint8_t *)secret, CHALLENGE_SECRET_LENGTH);
 300                 *r_response = malloc(SHA_DIGEST_LENGTH);
 301                 SHA1_Final((uint8_t *)*r_response, &ctx);
 302
 303                 length = RSA_size(rsa);
 304                 tmp = rb_malloc(length);
 305                 ret = RSA_public_encrypt(CHALLENGE_SECRET_LENGTH, secret, tmp, rsa, RSA_PKCS1_OAEP_PADDING);
 306
 307                 if(ret >= 0)
 308                 {
 309                         *r_challenge = (char *)rb_base64_encode(tmp, ret);
 310                         rb_free(tmp);
 311                         return 0;
 312                 }
 313
 314                 rb_free(tmp);
 315                 rb_free(*r_response);
 316                 *r_response = NULL;
 317         }
 318
 319         ERR_load_crypto_strings();
 320         while ((cnt < 100) && (e = ERR_get_error()))
 321         {
 322                 ilog(L_MAIN, "SSL error: %s", ERR_error_string(e, 0));
 323                 cnt++;
 324         }
 325
 326         return (-1);
 327 }
 328
 329 #endif /* HAVE_LIBCRYPTO */