source/libsmb/ntlm_check.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Password and authentication handling
   4    Copyright (C) Andrew Tridgell              1992-2000
   5    Copyright (C) Luke Kenneth Casson Leighton 1996-2000
   6    Copyright (C) Andrew Bartlett              2001-2003
   7    Copyright (C) Gerald Carter                2003
   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 3 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, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24
  25 #undef DBGC_CLASS
  26 #define DBGC_CLASS DBGC_AUTH
  27
  28 /****************************************************************************
  29  Core of smb password checking routine.
  30 ****************************************************************************/
  31
  32 static bool smb_pwd_check_ntlmv1(const DATA_BLOB *nt_response,
  33                                  const uchar *part_passwd,
  34                                  const DATA_BLOB *sec_blob,
  35                                  DATA_BLOB *user_sess_key)
  36 {
  37         /* Finish the encryption of part_passwd. */
  38         uchar p24[24];
  39
  40         if (part_passwd == NULL) {
  41                 DEBUG(10,("No password set - DISALLOWING access\n"));
  42                 /* No password set - always false ! */
  43                 return False;
  44         }
  45
  46         if (sec_blob->length != 8) {
  47                 DEBUG(0, ("smb_pwd_check_ntlmv1: incorrect challenge size (%lu)\n",
  48                           (unsigned long)sec_blob->length));
  49                 return False;
  50         }
  51
  52         if (nt_response->length != 24) {
  53                 DEBUG(0, ("smb_pwd_check_ntlmv1: incorrect password length (%lu)\n",
  54                           (unsigned long)nt_response->length));
  55                 return False;
  56         }
  57
  58         SMBOWFencrypt(part_passwd, sec_blob->data, p24);
  59         if (user_sess_key != NULL) {
  60                 *user_sess_key = data_blob(NULL, 16);
  61                 SMBsesskeygen_ntv1(part_passwd, NULL, user_sess_key->data);
  62         }
  63
  64
  65 #ifdef DEBUG_PASSWORD
  66         DEBUG(100,("Part password (P16) was |\n"));
  67         dump_data(100, part_passwd, 16);
  68         DEBUGADD(100,("Password from client was |\n"));
  69         dump_data(100, nt_response->data, nt_response->length);
  70         DEBUGADD(100,("Given challenge was |\n"));
  71         dump_data(100, sec_blob->data, sec_blob->length);
  72         DEBUGADD(100,("Value from encryption was |\n"));
  73         dump_data(100, p24, 24);
  74 #endif
  75         return (memcmp(p24, nt_response->data, 24) == 0);
  76 }
  77
  78 /****************************************************************************
  79  Core of smb password checking routine. (NTLMv2, LMv2)
  80  Note:  The same code works with both NTLMv2 and LMv2.
  81 ****************************************************************************/
  82
  83 static bool smb_pwd_check_ntlmv2(const DATA_BLOB *ntv2_response,
  84                                  const uchar *part_passwd,
  85                                  const DATA_BLOB *sec_blob,
  86                                  const char *user, const char *domain,
  87                                  bool upper_case_domain, /* should the domain be transformed into upper case? */
  88                                  DATA_BLOB *user_sess_key)
  89 {
  90         /* Finish the encryption of part_passwd. */
  91         uchar kr[16];
  92         uchar value_from_encryption[16];
  93         uchar client_response[16];
  94         DATA_BLOB client_key_data;
  95         bool res;
  96
  97         if (part_passwd == NULL) {
  98                 DEBUG(10,("No password set - DISALLOWING access\n"));
  99                 /* No password set - always False */
 100                 return False;
 101         }
 102
 103         if (sec_blob->length != 8) {
 104                 DEBUG(0, ("smb_pwd_check_ntlmv2: incorrect challenge size (%lu)\n",
 105                           (unsigned long)sec_blob->length));
 106                 return False;
 107         }
 108
 109         if (ntv2_response->length < 24) {
 110                 /* We MUST have more than 16 bytes, or the stuff below will go
 111                    crazy.  No known implementation sends less than the 24 bytes
 112                    for LMv2, let alone NTLMv2. */
 113                 DEBUG(0, ("smb_pwd_check_ntlmv2: incorrect password length (%lu)\n",
 114                           (unsigned long)ntv2_response->length));
 115                 return False;
 116         }
 117
 118         client_key_data = data_blob(ntv2_response->data+16, ntv2_response->length-16);
 119         /*
 120            todo:  should we be checking this for anything?  We can't for LMv2,
 121            but for NTLMv2 it is meant to contain the current time etc.
 122         */
 123
 124         memcpy(client_response, ntv2_response->data, sizeof(client_response));
 125
 126         if (!ntv2_owf_gen(part_passwd, user, domain, upper_case_domain, kr)) {
 127                 return False;
 128         }
 129
 130         SMBOWFencrypt_ntv2(kr, sec_blob, &client_key_data, value_from_encryption);
 131         if (user_sess_key != NULL) {
 132                 *user_sess_key = data_blob(NULL, 16);
 133                 SMBsesskeygen_ntv2(kr, value_from_encryption, user_sess_key->data);
 134         }
 135
 136 #if DEBUG_PASSWORD
 137         DEBUG(100,("Part password (P16) was |\n"));
 138         dump_data(100, part_passwd, 16);
 139         DEBUGADD(100,("Password from client was |\n"));
 140         dump_data(100, ntv2_response->data, ntv2_response->length);
 141         DEBUGADD(100,("Variable data from client was |\n"));
 142         dump_data(100, client_key_data.data, client_key_data.length);
 143         DEBUGADD(100,("Given challenge was |\n"));
 144         dump_data(100, sec_blob->data, sec_blob->length);
 145         DEBUGADD(100,("Value from encryption was |\n"));
 146         dump_data(100, value_from_encryption, 16);
 147 #endif
 148         data_blob_clear_free(&client_key_data);
 149         res = (memcmp(value_from_encryption, client_response, 16) == 0);
 150         if ((!res) && (user_sess_key != NULL))
 151                 data_blob_clear_free(user_sess_key);
 152         return res;
 153 }
 154
 155 /**
 156  * Check a challenge-response password against the value of the NT or
 157  * LM password hash.
 158  *
 159  * @param mem_ctx talloc context
 160  * @param challenge 8-byte challenge.  If all zero, forces plaintext comparison
 161  * @param nt_response 'unicode' NT response to the challenge, or unicode password
 162  * @param lm_response ASCII or LANMAN response to the challenge, or password in DOS code page
 163  * @param username internal Samba username, for log messages
 164  * @param client_username username the client used
 165  * @param client_domain domain name the client used (may be mapped)
 166  * @param nt_pw MD4 unicode password from our passdb or similar
 167  * @param lm_pw LANMAN ASCII password from our passdb or similar
 168  * @param user_sess_key User session key
 169  * @param lm_sess_key LM session key (first 8 bytes of the LM hash)
 170  */
 171
 172 NTSTATUS ntlm_password_check(TALLOC_CTX *mem_ctx,
 173                              const DATA_BLOB *challenge,
 174                              const DATA_BLOB *lm_response,
 175                              const DATA_BLOB *nt_response,
 176                              const DATA_BLOB *lm_interactive_pwd,
 177                              const DATA_BLOB *nt_interactive_pwd,
 178                              const char *username,
 179                              const char *client_username,
 180                              const char *client_domain,
 181                              const uint8 *lm_pw, const uint8 *nt_pw,
 182                              DATA_BLOB *user_sess_key,
 183                              DATA_BLOB *lm_sess_key)
 184 {
 185         unsigned char zeros[8];
 186
 187         ZERO_STRUCT(zeros);
 188
 189         if (nt_pw == NULL) {
 190                 DEBUG(3,("ntlm_password_check: NO NT password stored for user %s.\n",
 191                          username));
 192         }
 193
 194         if (nt_interactive_pwd && nt_interactive_pwd->length && nt_pw) {
 195                 if (nt_interactive_pwd->length != 16) {
 196                         DEBUG(3,("ntlm_password_check: Interactive logon: Invalid NT password length (%d) supplied for user %s\n", (int)nt_interactive_pwd->length,
 197                                  username));
 198                         return NT_STATUS_WRONG_PASSWORD;
 199                 }
 200
 201                 if (memcmp(nt_interactive_pwd->data, nt_pw, 16) == 0) {
 202                         if (user_sess_key) {
 203                                 *user_sess_key = data_blob(NULL, 16);
 204                                 SMBsesskeygen_ntv1(nt_pw, NULL, user_sess_key->data);
 205                         }
 206                         return NT_STATUS_OK;
 207                 } else {
 208                         DEBUG(3,("ntlm_password_check: Interactive logon: NT password check failed for user %s\n",
 209                                  username));
 210                         return NT_STATUS_WRONG_PASSWORD;
 211                 }
 212
 213         } else if (lm_interactive_pwd && lm_interactive_pwd->length && lm_pw) {
 214                 if (lm_interactive_pwd->length != 16) {
 215                         DEBUG(3,("ntlm_password_check: Interactive logon: Invalid LANMAN password length (%d) supplied for user %s\n", (int)lm_interactive_pwd->length,
 216                                  username));
 217                         return NT_STATUS_WRONG_PASSWORD;
 218                 }
 219
 220                 if (!lp_lanman_auth()) {
 221                         DEBUG(3,("ntlm_password_check: Interactive logon: only LANMAN password supplied for user %s, and LM passwords are disabled!\n",
 222                                  username));
 223                         return NT_STATUS_WRONG_PASSWORD;
 224                 }
 225
 226                 if (memcmp(lm_interactive_pwd->data, lm_pw, 16) == 0) {
 227                         return NT_STATUS_OK;
 228                 } else {
 229                         DEBUG(3,("ntlm_password_check: Interactive logon: LANMAN password check failed for user %s\n",
 230                                  username));
 231                         return NT_STATUS_WRONG_PASSWORD;
 232                 }
 233         }
 234
 235         /* Check for cleartext netlogon. Used by Exchange 5.5. */
 236         if (challenge->length == sizeof(zeros) &&
 237             (memcmp(challenge->data, zeros, challenge->length) == 0 )) {
 238
 239                 DEBUG(4,("ntlm_password_check: checking plaintext passwords for user %s\n",
 240                          username));
 241                 if (nt_pw && nt_response->length) {
 242                         unsigned char pwhash[16];
 243                         mdfour(pwhash, nt_response->data, nt_response->length);
 244                         if (memcmp(pwhash, nt_pw, sizeof(pwhash)) == 0) {
 245                                 return NT_STATUS_OK;
 246                         } else {
 247                                 DEBUG(3,("ntlm_password_check: NT (Unicode) plaintext password check failed for user %s\n",
 248                                          username));
 249                                 return NT_STATUS_WRONG_PASSWORD;
 250                         }
 251
 252                 } else if (!lp_lanman_auth()) {
 253                         DEBUG(3,("ntlm_password_check: (plaintext password check) LANMAN passwords NOT PERMITTED for user %s\n",
 254                                  username));
 255
 256                 } else if (lm_pw && lm_response->length) {
 257                         uchar dospwd[14];
 258                         uchar p16[16];
 259                         ZERO_STRUCT(dospwd);
 260
 261                         memcpy(dospwd, lm_response->data, MIN(lm_response->length, sizeof(dospwd)));
 262                         /* Only the fisrt 14 chars are considered, password need not be null terminated. */
 263
 264                         /* we *might* need to upper-case the string here */
 265                         E_P16((const unsigned char *)dospwd, p16);
 266
 267                         if (memcmp(p16, lm_pw, sizeof(p16)) == 0) {
 268                                 return NT_STATUS_OK;
 269                         } else {
 270                                 DEBUG(3,("ntlm_password_check: LANMAN (ASCII) plaintext password check failed for user %s\n",
 271                                          username));
 272                                 return NT_STATUS_WRONG_PASSWORD;
 273                         }
 274                 } else {
 275                         DEBUG(3, ("Plaintext authentication for user %s attempted, but neither NT nor LM passwords available\n", username));
 276                         return NT_STATUS_WRONG_PASSWORD;
 277                 }
 278         }
 279
 280         if (nt_response->length != 0 && nt_response->length < 24) {
 281                 DEBUG(2,("ntlm_password_check: invalid NT password length (%lu) for user %s\n",
 282                          (unsigned long)nt_response->length, username));
 283         }
 284
 285         if (nt_response->length >= 24 && nt_pw) {
 286                 if (nt_response->length > 24) {
 287                         /* We have the NT MD4 hash challenge available - see if we can
 288                            use it
 289                         */
 290                         DEBUG(4,("ntlm_password_check: Checking NTLMv2 password with domain [%s]\n", client_domain));
 291                         if (smb_pwd_check_ntlmv2( nt_response,
 292                                                   nt_pw, challenge,
 293                                                   client_username,
 294                                                   client_domain,
 295                                                   False,
 296                                                   user_sess_key)) {
 297                                 return NT_STATUS_OK;
 298                         }
 299
 300                         DEBUG(4,("ntlm_password_check: Checking NTLMv2 password with uppercased version of domain [%s]\n", client_domain));
 301                         if (smb_pwd_check_ntlmv2( nt_response,
 302                                                   nt_pw, challenge,
 303                                                   client_username,
 304                                                   client_domain,
 305                                                   True,
 306                                                   user_sess_key)) {
 307                                 return NT_STATUS_OK;
 308                         }
 309
 310                         DEBUG(4,("ntlm_password_check: Checking NTLMv2 password without a domain\n"));
 311                         if (smb_pwd_check_ntlmv2( nt_response,
 312                                                   nt_pw, challenge,
 313                                                   client_username,
 314                                                   "",
 315                                                   False,
 316                                                   user_sess_key)) {
 317                                 return NT_STATUS_OK;
 318                         } else {
 319                                 DEBUG(3,("ntlm_password_check: NTLMv2 password check failed\n"));
 320                                 return NT_STATUS_WRONG_PASSWORD;
 321                         }
 322                 }
 323
 324                 if (lp_ntlm_auth()) {
 325                         /* We have the NT MD4 hash challenge available - see if we can
 326                            use it (ie. does it exist in the smbpasswd file).
 327                         */
 328                         DEBUG(4,("ntlm_password_check: Checking NT MD4 password\n"));
 329                         if (smb_pwd_check_ntlmv1(nt_response,
 330                                                  nt_pw, challenge,
 331                                                  user_sess_key)) {
 332                                 /* The LM session key for this response is not very secure,
 333                                    so use it only if we otherwise allow LM authentication */
 334
 335                                 if (lp_lanman_auth() && lm_pw) {
 336                                         uint8 first_8_lm_hash[16];
 337                                         memcpy(first_8_lm_hash, lm_pw, 8);
 338                                         memset(first_8_lm_hash + 8, '\0', 8);
 339                                         if (lm_sess_key) {
 340                                                 *lm_sess_key = data_blob(first_8_lm_hash, 16);
 341                                         }
 342                                 }
 343                                 return NT_STATUS_OK;
 344                         } else {
 345                                 DEBUG(3,("ntlm_password_check: NT MD4 password check failed for user %s\n",
 346                                          username));
 347                                 return NT_STATUS_WRONG_PASSWORD;
 348                         }
 349                 } else {
 350                         DEBUG(2,("ntlm_password_check: NTLMv1 passwords NOT PERMITTED for user %s\n",
 351                                  username));
 352                         /* no return, becouse we might pick up LMv2 in the LM field */
 353                 }
 354         }
 355
 356         if (lm_response->length == 0) {
 357                 DEBUG(3,("ntlm_password_check: NEITHER LanMan nor NT password supplied for user %s\n",
 358                          username));
 359                 return NT_STATUS_WRONG_PASSWORD;
 360         }
 361
 362         if (lm_response->length < 24) {
 363                 DEBUG(2,("ntlm_password_check: invalid LanMan password length (%lu) for user %s\n",
 364                          (unsigned long)nt_response->length, username));
 365                 return NT_STATUS_WRONG_PASSWORD;
 366         }
 367
 368         if (!lp_lanman_auth()) {
 369                 DEBUG(3,("ntlm_password_check: Lanman passwords NOT PERMITTED for user %s\n",
 370                          username));
 371         } else if (!lm_pw) {
 372                 DEBUG(3,("ntlm_password_check: NO LanMan password set for user %s (and no NT password supplied)\n",
 373                          username));
 374         } else {
 375                 DEBUG(4,("ntlm_password_check: Checking LM password\n"));
 376                 if (smb_pwd_check_ntlmv1(lm_response,
 377                                          lm_pw, challenge,
 378                                          NULL)) {
 379                         uint8 first_8_lm_hash[16];
 380                         memcpy(first_8_lm_hash, lm_pw, 8);
 381                         memset(first_8_lm_hash + 8, '\0', 8);
 382                         if (user_sess_key) {
 383                                 *user_sess_key = data_blob(first_8_lm_hash, 16);
 384                         }
 385
 386                         if (lm_sess_key) {
 387                                 *lm_sess_key = data_blob(first_8_lm_hash, 16);
 388                         }
 389                         return NT_STATUS_OK;
 390                 }
 391         }
 392
 393         if (!nt_pw) {
 394                 DEBUG(4,("ntlm_password_check: LM password check failed for user, no NT password %s\n",username));
 395                 return NT_STATUS_WRONG_PASSWORD;
 396         }
 397
 398         /* This is for 'LMv2' authentication.  almost NTLMv2 but limited to 24 bytes.
 399            - related to Win9X, legacy NAS pass-though authentication
 400         */
 401         DEBUG(4,("ntlm_password_check: Checking LMv2 password with domain %s\n", client_domain));
 402         if (smb_pwd_check_ntlmv2( lm_response,
 403                                   nt_pw, challenge,
 404                                   client_username,
 405                                   client_domain,
 406                                   False,
 407                                   NULL)) {
 408                 return NT_STATUS_OK;
 409         }
 410
 411         DEBUG(4,("ntlm_password_check: Checking LMv2 password with upper-cased version of domain %s\n", client_domain));
 412         if (smb_pwd_check_ntlmv2( lm_response,
 413                                   nt_pw, challenge,
 414                                   client_username,
 415                                   client_domain,
 416                                   True,
 417                                   NULL)) {
 418                 return NT_STATUS_OK;
 419         }
 420
 421         DEBUG(4,("ntlm_password_check: Checking LMv2 password without a domain\n"));
 422         if (smb_pwd_check_ntlmv2( lm_response,
 423                                   nt_pw, challenge,
 424                                   client_username,
 425                                   "",
 426                                   False,
 427                                   NULL)) {
 428                 return NT_STATUS_OK;
 429         }
 430
 431         /* Apparently NT accepts NT responses in the LM field
 432            - I think this is related to Win9X pass-though authentication
 433         */
 434         DEBUG(4,("ntlm_password_check: Checking NT MD4 password in LM field\n"));
 435         if (lp_ntlm_auth()) {
 436                 if (smb_pwd_check_ntlmv1(lm_response,
 437                                          nt_pw, challenge,
 438                                          NULL)) {
 439                         /* The session key for this response is still very odd.
 440                            It not very secure, so use it only if we otherwise
 441                            allow LM authentication */
 442
 443                         if (lp_lanman_auth() && lm_pw) {
 444                                 uint8 first_8_lm_hash[16];
 445                                 memcpy(first_8_lm_hash, lm_pw, 8);
 446                                 memset(first_8_lm_hash + 8, '\0', 8);
 447                                 if (user_sess_key) {
 448                                         *user_sess_key = data_blob(first_8_lm_hash, 16);
 449                                 }
 450
 451                                 if (lm_sess_key) {
 452                                         *lm_sess_key = data_blob(first_8_lm_hash, 16);
 453                                 }
 454                         }
 455                         return NT_STATUS_OK;
 456                 }
 457                 DEBUG(3,("ntlm_password_check: LM password, NT MD4 password in LM field and LMv2 failed for user %s\n",username));
 458         } else {
 459                 DEBUG(3,("ntlm_password_check: LM password and LMv2 failed for user %s, and NT MD4 password in LM field not permitted\n",username));
 460         }
 461         return NT_STATUS_WRONG_PASSWORD;
 462 }
 463