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 DECLARE_MODULE_AV2(challenge, challenge_load, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
  71 #else
  72
  73 static int m_challenge(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
  74
  75 /* We have openssl support, so include /CHALLENGE */
  76 struct Message challenge_msgtab = {
  77         "CHALLENGE", 0, 0, 0, 0,
  78         {mg_unreg, {m_challenge, 2}, mg_ignore, mg_ignore, mg_ignore, {m_challenge, 2}}
  79 };
  80
  81 mapi_clist_av1 challenge_clist[] = { &challenge_msgtab, NULL };
  82 DECLARE_MODULE_AV2(challenge, NULL, NULL, challenge_clist, NULL, NULL, NULL, NULL, NULL);
  83
  84 static int generate_challenge(char **r_challenge, char **r_response, RSA * key);
  85
  86 static void
  87 cleanup_challenge(struct Client *target_p)
  88 {
  89         if(target_p->localClient == NULL)
  90                 return;
  91
  92         rb_free(target_p->localClient->challenge);
  93         rb_free(target_p->localClient->opername);
  94         target_p->localClient->challenge = NULL;
  95         target_p->localClient->opername = NULL;
  96         target_p->localClient->chal_time = 0;
  97 }
  98
  99 /*
 100  * m_challenge - generate RSA challenge for wouldbe oper
 101  * parv[1] = operator to challenge for, or +response
 102  */
 103 static int
 104 m_challenge(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
 105 {
 106         struct oper_conf *oper_p;
 107         char *challenge = NULL; /* to placate gcc */
 108         char chal_line[CHALLENGE_WIDTH];
 109         unsigned char *b_response;
 110         size_t cnt;
 111         int len = 0;
 112
 113         /* if theyre an oper, reprint oper motd and ignore */
 114         if(IsOper(source_p))
 115         {
 116                 sendto_one(source_p, form_str(RPL_YOUREOPER), me.name, source_p->name);
 117                 send_oper_motd(source_p);
 118                 return 0;
 119         }
 120
 121         if(*parv[1] == '+')
 122         {
 123                 /* Ignore it if we aren't expecting this... -A1kmm */
 124                 if(!source_p->localClient->challenge)
 125                         return 0;
 126
 127                 if((rb_current_time() - source_p->localClient->chal_time) > CHALLENGE_EXPIRES)
 128                 {
 129                         sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
 130                         ilog(L_FOPER, "EXPIRED CHALLENGE (%s) by (%s!%s@%s) (%s)",
 131                              source_p->localClient->opername, source_p->name,
 132                              source_p->username, source_p->host, source_p->sockhost);
 133
 134                         if(ConfigFileEntry.failed_oper_notice)
 135                                 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 136                                                      "Expired CHALLENGE attempt by %s (%s@%s)",
 137                                                      source_p->name, source_p->username,
 138                                                      source_p->host);
 139                         cleanup_challenge(source_p);
 140                         return 0;
 141                 }
 142
 143                 parv[1]++;
 144                 b_response = rb_base64_decode((const unsigned char *)parv[1], strlen(parv[1]), &len);
 145
 146                 if(len != SHA_DIGEST_LENGTH ||
 147                    memcmp(source_p->localClient->challenge, b_response, SHA_DIGEST_LENGTH))
 148                 {
 149                         sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
 150                         ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s)",
 151                              source_p->localClient->opername, source_p->name,
 152                              source_p->username, source_p->host, source_p->sockhost);
 153
 154                         if(ConfigFileEntry.failed_oper_notice)
 155                                 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 156                                                      "Failed CHALLENGE attempt by %s (%s@%s)",
 157                                                      source_p->name, source_p->username,
 158                                                      source_p->host);
 159
 160                         rb_free(b_response);
 161                         cleanup_challenge(source_p);
 162                         return 0;
 163                 }
 164
 165                 rb_free(b_response);
 166
 167                 oper_p = find_oper_conf(source_p->username, source_p->orighost,
 168                                         source_p->sockhost,
 169                                         source_p->localClient->opername);
 170
 171                 if(oper_p == NULL)
 172                 {
 173                         sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 174                         ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
 175                              source_p->localClient->opername, source_p->name,
 176                              source_p->username, source_p->host,
 177                              source_p->sockhost);
 178
 179                         if(ConfigFileEntry.failed_oper_notice)
 180                                 sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 181                                                      "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
 182                                                      source_p->name, source_p->username,
 183                                                      source_p->host);
 184                         return 0;
 185                 }
 186
 187                 cleanup_challenge(source_p);
 188
 189                 oper_up(source_p, oper_p);
 190
 191                 ilog(L_OPERED, "OPER %s by %s!%s@%s (%s)",
 192                      source_p->localClient->opername, source_p->name,
 193                      source_p->username, source_p->host, source_p->sockhost);
 194                 return 0;
 195         }
 196
 197         cleanup_challenge(source_p);
 198
 199         oper_p = find_oper_conf(source_p->username, source_p->orighost,
 200                                 source_p->sockhost, parv[1]);
 201
 202         if(oper_p == NULL)
 203         {
 204                 sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 205                 ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
 206                      parv[1], source_p->name,
 207                      source_p->username, source_p->host, source_p->sockhost);
 208
 209                 if(ConfigFileEntry.failed_oper_notice)
 210                         sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 211                                              "Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
 212                                              source_p->name, source_p->username, source_p->host);
 213                 return 0;
 214         }
 215
 216         if(!oper_p->rsa_pubkey)
 217         {
 218                 sendto_one_notice(source_p, ":I'm sorry, PK authentication is not enabled for your oper{} block.");
 219                 return 0;
 220         }
 221
 222         if(IsOperConfNeedSSL(oper_p) && !IsSSLClient(source_p))
 223         {
 224                 sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 225                 ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s) -- requires SSL/TLS",
 226                      parv[1], source_p->name, source_p->username, source_p->host,
 227                      source_p->sockhost);
 228
 229                 if(ConfigFileEntry.failed_oper_notice)
 230                 {
 231                         sendto_realops_snomask(SNO_GENERAL, L_ALL,
 232                                              "Failed CHALLENGE attempt - missing SSL/TLS by %s (%s@%s)",
 233                                              source_p->name, source_p->username, source_p->host);
 234                 }
 235                 return 0;
 236         }
 237
 238         if (oper_p->certfp != NULL)
 239         {
 240                 if (source_p->certfp == NULL || strcasecmp(source_p->certfp, oper_p->certfp))
 241                 {
 242                         sendto_one_numeric(source_p, ERR_NOOPERHOST, form_str(ERR_NOOPERHOST));
 243                         ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s) -- client certificate fingerprint mismatch",
 244                              parv[1], source_p->name,
 245                              source_p->username, source_p->host, source_p->sockhost);
 246
 247                         if(ConfigFileEntry.failed_oper_notice)
 248                         {
 249                                 sendto_realops_snomask(SNO_GENERAL, L_ALL,
 250                                                      "Failed OPER attempt - client certificate fingerprint mismatch by %s (%s@%s)",
 251                                                      source_p->name, source_p->username, source_p->host);
 252                         }
 253                         return 0;
 254                 }
 255         }
 256
 257         if(!generate_challenge(&challenge, &(source_p->localClient->challenge), oper_p->rsa_pubkey))
 258         {
 259                 char *chal = challenge;
 260                 source_p->localClient->chal_time = rb_current_time();
 261                 for(;;)
 262                 {
 263                         cnt = rb_strlcpy(chal_line, chal, CHALLENGE_WIDTH);
 264                         sendto_one(source_p, form_str(RPL_RSACHALLENGE2), me.name, source_p->name, chal_line);
 265                         if(cnt > CHALLENGE_WIDTH)
 266                                 chal += CHALLENGE_WIDTH - 1;
 267                         else
 268                                 break;
 269
 270                 }
 271                 sendto_one(source_p, form_str(RPL_ENDOFRSACHALLENGE2),
 272                            me.name, source_p->name);
 273                 rb_free(challenge);
 274                 source_p->localClient->opername = rb_strdup(oper_p->name);
 275         }
 276         else
 277                 sendto_one_notice(source_p, ":Failed to generate challenge.");
 278
 279         return 0;
 280 }
 281
 282 static int
 283 generate_challenge(char **r_challenge, char **r_response, RSA * rsa)
 284 {
 285         SHA_CTX ctx;
 286         unsigned char secret[CHALLENGE_SECRET_LENGTH], *tmp;
 287         unsigned long length;
 288         unsigned long e = 0;
 289         unsigned long cnt = 0;
 290         int ret;
 291
 292         if(!rsa)
 293                 return -1;
 294         if(rb_get_random(secret, CHALLENGE_SECRET_LENGTH))
 295         {
 296                 SHA1_Init(&ctx);
 297                 SHA1_Update(&ctx, (uint8_t *)secret, CHALLENGE_SECRET_LENGTH);
 298                 *r_response = malloc(SHA_DIGEST_LENGTH);
 299                 SHA1_Final((uint8_t *)*r_response, &ctx);
 300
 301                 length = RSA_size(rsa);
 302                 tmp = rb_malloc(length);
 303                 ret = RSA_public_encrypt(CHALLENGE_SECRET_LENGTH, secret, tmp, rsa, RSA_PKCS1_OAEP_PADDING);
 304
 305                 if(ret >= 0)
 306                 {
 307                         *r_challenge = (char *)rb_base64_encode(tmp, ret);
 308                         rb_free(tmp);
 309                         return 0;
 310                 }
 311
 312                 rb_free(tmp);
 313                 rb_free(*r_response);
 314                 *r_response = NULL;
 315         }
 316
 317         ERR_load_crypto_strings();
 318         while ((cnt < 100) && (e = ERR_get_error()))
 319         {
 320                 ilog(L_MAIN, "SSL error: %s", ERR_error_string(e, 0));
 321                 cnt++;
 322         }
 323
 324         return (-1);
 325 }
 326
 327 #endif /* HAVE_LIBCRYPTO */