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 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., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "includes.h"
  25
  26 #undef DBGC_CLASS
  27 #define DBGC_CLASS DBGC_AUTH
  28
  29 /****************************************************************************
  30  Core of smb password checking routine.
  31 ****************************************************************************/
  32
  33 static BOOL smb_pwd_check_ntlmv1(const DATA_BLOB *nt_response,
  34                                  const uchar *part_passwd,
  35                                  const DATA_BLOB *sec_blob,
  36                                  DATA_BLOB *user_sess_key)
  37 {
  38         /* Finish the encryption of part_passwd. */
  39         uchar p24[24];
  40
  41         if (part_passwd == NULL) {
  42                 DEBUG(10,("No password set - DISALLOWING access\n"));
  43                 /* No password set - always false ! */
  44                 return False;
  45         }
  46
  47         if (sec_blob->length != 8) {
  48                 DEBUG(0, ("smb_pwd_check_ntlmv1: incorrect challenge size (%lu)\n",
  49                           (unsigned long)sec_blob->length));
  50                 return False;
  51         }
  52
  53         if (nt_response->length != 24) {
  54                 DEBUG(0, ("smb_pwd_check_ntlmv1: incorrect password length (%lu)\n",
  55                           (unsigned long)nt_response->length));
  56                 return False;
  57         }
  58
  59         SMBOWFencrypt(part_passwd, sec_blob->data, p24);
  60         if (user_sess_key != NULL) {
  61                 *user_sess_key = data_blob(NULL, 16);
  62                 SMBsesskeygen_ntv1(part_passwd, NULL, user_sess_key->data);
  63         }
  64
  65
  66 #if DEBUG_PASSWORD
  67         DEBUG(100,("Part password (P16) was |\n"));
  68         dump_data(100, part_passwd, 16);
  69         DEBUGADD(100,("Password from client was |\n"));
  70         dump_data(100, nt_response->data, nt_response->length);
  71         DEBUGADD(100,("Given challenge was |\n"));
  72         dump_data(100, sec_blob->data, sec_blob->length);
  73         DEBUGADD(100,("Value from encryption was |\n"));
  74         dump_data(100, p24, 24);
  75 #endif
  76         return (memcmp(p24, nt_response->data, 24) == 0);
  77 }
  78
  79 /****************************************************************************
  80  Core of smb password checking routine. (NTLMv2, LMv2)
  81  Note:  The same code works with both NTLMv2 and LMv2.
  82 ****************************************************************************/
  83
  84 static BOOL smb_pwd_check_ntlmv2(const DATA_BLOB *ntv2_response,
  85                                  const uchar *part_passwd,
  86                                  const DATA_BLOB *sec_blob,
  87                                  const char *user, const char *domain,
  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
  96         if (part_passwd == NULL) {
  97                 DEBUG(10,("No password set - DISALLOWING access\n"));
  98                 /* No password set - always False */
  99                 return False;
 100         }
 101
 102         if (sec_blob->length != 8) {
 103                 DEBUG(0, ("smb_pwd_check_ntlmv2: incorrect challenge size (%lu)\n",
 104                           (unsigned long)sec_blob->length));
 105                 return False;
 106         }
 107
 108         if (ntv2_response->length < 24) {
 109                 /* We MUST have more than 16 bytes, or the stuff below will go
 110                    crazy.  No known implementation sends less than the 24 bytes
 111                    for LMv2, let alone NTLMv2. */
 112                 DEBUG(0, ("smb_pwd_check_ntlmv2: incorrect password length (%lu)\n",
 113                           (unsigned long)ntv2_response->length));
 114                 return False;
 115         }
 116
 117         client_key_data = data_blob(ntv2_response->data+16, ntv2_response->length-16);
 118         /*
 119            todo:  should we be checking this for anything?  We can't for LMv2,
 120            but for NTLMv2 it is meant to contain the current time etc.
 121         */
 122
 123         memcpy(client_response, ntv2_response->data, sizeof(client_response));
 124
 125         if (!ntv2_owf_gen(part_passwd, user, domain, kr)) {
 126                 return False;
 127         }
 128
 129         SMBOWFencrypt_ntv2(kr, sec_blob, &client_key_data, value_from_encryption);
 130         if (user_sess_key != NULL) {
 131                 *user_sess_key = data_blob(NULL, 16);
 132                 SMBsesskeygen_ntv2(kr, value_from_encryption, user_sess_key->data);
 133         }
 134
 135 #if DEBUG_PASSWORD
 136         DEBUG(100,("Part password (P16) was |\n"));
 137         dump_data(100, part_passwd, 16);
 138         DEBUGADD(100,("Password from client was |\n"));
 139         dump_data(100, ntv2_response->data, ntv2_response->length);
 140         DEBUGADD(100,("Variable data from client was |\n"));
 141         dump_data(100, client_key_data.data, client_key_data.length);
 142         DEBUGADD(100,("Given challenge was |\n"));
 143         dump_data(100, sec_blob->data, sec_blob->length);
 144         DEBUGADD(100,("Value from encryption was |\n"));
 145         dump_data(100, value_from_encryption, 16);
 146 #endif
 147         data_blob_clear_free(&client_key_data);
 148         return (memcmp(value_from_encryption, client_response, 16) == 0);
 149 }
 150
 151 /**
 152  * Check a challenge-response password against the value of the NT or
 153  * LM password hash.
 154  *
 155  * @param mem_ctx talloc context
 156  * @param challenge 8-byte challenge.  If all zero, forces plaintext comparison
 157  * @param nt_response 'unicode' NT response to the challenge, or unicode password
 158  * @param lm_response ASCII or LANMAN response to the challenge, or password in DOS code page
 159  * @param username internal Samba username, for log messages
 160  * @param client_username username the client used
 161  * @param client_domain domain name the client used (may be mapped)
 162  * @param nt_pw MD4 unicode password from our passdb or similar
 163  * @param lm_pw LANMAN ASCII password from our passdb or similar
 164  * @param user_sess_key User session key
 165  * @param lm_sess_key LM session key (first 8 bytes of the LM hash)
 166  */
 167
 168 NTSTATUS ntlm_password_check(TALLOC_CTX *mem_ctx,
 169                              const DATA_BLOB *challenge,
 170                              const DATA_BLOB *lm_response,
 171                              const DATA_BLOB *nt_response,
 172                              const char *username,
 173                              const char *client_username,
 174                              const char *client_domain,
 175                              const uint8 *lm_pw, const uint8 *nt_pw,
 176                              DATA_BLOB *user_sess_key,
 177                              DATA_BLOB *lm_sess_key)
 178 {
 179         static const unsigned char zeros[8];
 180         if (nt_pw == NULL) {
 181                 DEBUG(3,("ntlm_password_check: NO NT password stored for user %s.\n",
 182                          username));
 183         }
 184
 185         /* Check for cleartext netlogon. Used by Exchange 5.5. */
 186         if (challenge->length == sizeof(zeros) &&
 187             (memcmp(challenge->data, zeros, challenge->length) == 0 )) {
 188
 189                 DEBUG(4,("ntlm_password_check: checking plaintext passwords for user %s\n",
 190                          username));
 191                 if (nt_pw && nt_response->length) {
 192                         unsigned char pwhash[16];
 193                         mdfour(pwhash, nt_response->data, nt_response->length);
 194                         if (memcmp(pwhash, nt_pw, sizeof(pwhash)) == 0) {
 195                                 return NT_STATUS_OK;
 196                         } else {
 197                                 DEBUG(3,("ntlm_password_check: NT (Unicode) plaintext password check failed for user %s\n",
 198                                          username));
 199                                 return NT_STATUS_WRONG_PASSWORD;
 200                         }
 201
 202                 } else if (!lp_lanman_auth()) {
 203                         DEBUG(3,("ntlm_password_check: (plaintext password check) LANMAN passwords NOT PERMITTED for user %s\n",
 204                                  username));
 205
 206                 } else if (lm_pw && lm_response->length) {
 207                         uchar dospwd[14];
 208                         uchar p16[16];
 209                         ZERO_STRUCT(dospwd);
 210
 211                         memcpy(dospwd, lm_response->data, MIN(lm_response->length, sizeof(dospwd)));
 212                         /* Only the fisrt 14 chars are considered, password need not be null terminated. */
 213
 214                         /* we *might* need to upper-case the string here */
 215                         E_P16((const unsigned char *)dospwd, p16);
 216
 217                         if (memcmp(p16, lm_pw, sizeof(p16)) == 0) {
 218                                 return NT_STATUS_OK;
 219                         } else {
 220                                 DEBUG(3,("ntlm_password_check: LANMAN (ASCII) plaintext password check failed for user %s\n",
 221                                          username));
 222                                 return NT_STATUS_WRONG_PASSWORD;
 223                         }
 224                 } else {
 225                         DEBUG(3, ("Plaintext authentication for user %s attempted, but neither NT nor LM passwords available\n", username));
 226                         return NT_STATUS_WRONG_PASSWORD;
 227                 }
 228         }
 229
 230         if (nt_response->length != 0 && nt_response->length < 24) {
 231                 DEBUG(2,("ntlm_password_check: invalid NT password length (%lu) for user %s\n",
 232                          (unsigned long)nt_response->length, username));
 233         }
 234
 235         if (nt_response->length >= 24 && nt_pw) {
 236                 if (nt_response->length > 24) {
 237                         /* We have the NT MD4 hash challenge available - see if we can
 238                            use it (ie. does it exist in the smbpasswd file).
 239                         */
 240                         DEBUG(4,("ntlm_password_check: Checking NTLMv2 password with domain [%s]\n", client_domain));
 241                         if (smb_pwd_check_ntlmv2( nt_response,
 242                                                   nt_pw, challenge,
 243                                           client_username,
 244                                                   client_domain,
 245                                                   user_sess_key)) {
 246                                 return NT_STATUS_OK;
 247                         }
 248
 249                         DEBUG(4,("ntlm_password_check: Checking NTLMv2 password without a domain\n"));
 250                         if (smb_pwd_check_ntlmv2( nt_response,
 251                                                   nt_pw, challenge,
 252                                                   client_username,
 253                                                   "",
 254                                                   user_sess_key)) {
 255                                 return NT_STATUS_OK;
 256                         } else {
 257                                 DEBUG(3,("ntlm_password_check: NTLMv2 password check failed\n"));
 258                                 return NT_STATUS_WRONG_PASSWORD;
 259                         }
 260                 }
 261
 262                 if (lp_ntlm_auth()) {
 263                         /* We have the NT MD4 hash challenge available - see if we can
 264                            use it (ie. does it exist in the smbpasswd file).
 265                         */
 266                         DEBUG(4,("ntlm_password_check: Checking NT MD4 password\n"));
 267                         if (smb_pwd_check_ntlmv1(nt_response,
 268                                                  nt_pw, challenge,
 269                                                  user_sess_key)) {
 270                                 /* The LM session key for this response is not very secure,
 271                                    so use it only if we otherwise allow LM authentication */
 272
 273                                 if (lp_lanman_auth() && lm_pw) {
 274                                         uint8 first_8_lm_hash[16];
 275                                         memcpy(first_8_lm_hash, lm_pw, 8);
 276                                         memset(first_8_lm_hash + 8, '\0', 8);
 277                                         *lm_sess_key = data_blob(first_8_lm_hash, 16);
 278                                 }
 279                                 return NT_STATUS_OK;
 280                         } else {
 281                                 DEBUG(3,("ntlm_password_check: NT MD4 password check failed for user %s\n",
 282                                          username));
 283                                 return NT_STATUS_WRONG_PASSWORD;
 284                         }
 285                 } else {
 286                         DEBUG(2,("ntlm_password_check: NTLMv1 passwords NOT PERMITTED for user %s\n",
 287                                  username));
 288                         /* no return, becouse we might pick up LMv2 in the LM field */
 289                 }
 290         }
 291
 292         if (lm_response->length == 0) {
 293                 DEBUG(3,("ntlm_password_check: NEITHER LanMan nor NT password supplied for user %s\n",
 294                          username));
 295                 return NT_STATUS_WRONG_PASSWORD;
 296         }
 297
 298         if (lm_response->length < 24) {
 299                 DEBUG(2,("ntlm_password_check: invalid LanMan password length (%lu) for user %s\n",
 300                          (unsigned long)nt_response->length, username));
 301                 return NT_STATUS_WRONG_PASSWORD;
 302         }
 303
 304         if (!lp_lanman_auth()) {
 305                 DEBUG(3,("ntlm_password_check: Lanman passwords NOT PERMITTED for user %s\n",
 306                          username));
 307         } else if (!lm_pw) {
 308                 DEBUG(3,("ntlm_password_check: NO LanMan password set for user %s (and no NT password supplied)\n",
 309                          username));
 310         } else {
 311                 DEBUG(4,("ntlm_password_check: Checking LM password\n"));
 312                 if (smb_pwd_check_ntlmv1(lm_response,
 313                                          lm_pw, challenge,
 314                                          NULL)) {
 315                         uint8 first_8_lm_hash[16];
 316                         memcpy(first_8_lm_hash, lm_pw, 8);
 317                         memset(first_8_lm_hash + 8, '\0', 8);
 318                         *user_sess_key = data_blob(first_8_lm_hash, 16);
 319                         *lm_sess_key = data_blob(first_8_lm_hash, 16);
 320                         return NT_STATUS_OK;
 321                 }
 322         }
 323
 324         if (!nt_pw) {
 325                 DEBUG(4,("ntlm_password_check: LM password check failed for user, no NT password %s\n",username));
 326                 return NT_STATUS_WRONG_PASSWORD;
 327         }
 328
 329         /* This is for 'LMv2' authentication.  almost NTLMv2 but limited to 24 bytes.
 330            - related to Win9X, legacy NAS pass-though authentication
 331         */
 332         DEBUG(4,("ntlm_password_check: Checking LMv2 password with domain %s\n", client_domain));
 333         if (smb_pwd_check_ntlmv2( lm_response,
 334                                   nt_pw, challenge,
 335                                   client_username,
 336                                   client_domain,
 337                                   NULL)) {
 338                 return NT_STATUS_OK;
 339         }
 340
 341         DEBUG(4,("ntlm_password_check: Checking LMv2 password without a domain\n"));
 342         if (smb_pwd_check_ntlmv2( lm_response,
 343                                   nt_pw, challenge,
 344                                   client_username,
 345                                   "",
 346                                   NULL)) {
 347                 return NT_STATUS_OK;
 348         }
 349
 350         /* Apparently NT accepts NT responses in the LM field
 351            - I think this is related to Win9X pass-though authentication
 352         */
 353         DEBUG(4,("ntlm_password_check: Checking NT MD4 password in LM field\n"));
 354         if (lp_ntlm_auth()) {
 355                 if (smb_pwd_check_ntlmv1(lm_response,
 356                                          nt_pw, challenge,
 357                                          NULL)) {
 358                         /* The session key for this response is still very odd.
 359                            It not very secure, so use it only if we otherwise
 360                            allow LM authentication */
 361
 362                         if (lp_lanman_auth() && lm_pw) {
 363                                 uint8 first_8_lm_hash[16];
 364                                 memcpy(first_8_lm_hash, lm_pw, 8);
 365                                 memset(first_8_lm_hash + 8, '\0', 8);
 366                                 *user_sess_key = data_blob(first_8_lm_hash, 16);
 367                                 *lm_sess_key = data_blob(first_8_lm_hash, 16);
 368                         }
 369                         return NT_STATUS_OK;
 370                 }
 371                 DEBUG(3,("ntlm_password_check: LM password, NT MD4 password in LM field and LMv2 failed for user %s\n",username));
 372         } else {
 373                 DEBUG(3,("ntlm_password_check: LM password and LMv2 failed for user %s, and NT MD4 password in LM field not permitted\n",username));
 374         }
 375         return NT_STATUS_WRONG_PASSWORD;
 376 }
 377