source/libsmb/smbencrypt.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    SMB parameters and setup
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Modified by Jeremy Allison 1995.
   6    Copyright (C) Jeremy Allison 1995-2000.
   7    Copyright (C) Luke Kennethc Casson Leighton 1996-2000.
   8    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program; if not, write to the Free Software
  22    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include "includes.h"
  26 #include "byteorder.h"
  27
  28 void SMBencrypt_hash(const uchar lm_hash[16], const uchar *c8, uchar p24[24])
  29 {
  30         uchar p21[21];
  31
  32         memset(p21,'\0',21);
  33         memcpy(p21, lm_hash, 16);
  34
  35         SMBOWFencrypt(p21, c8, p24);
  36
  37 #ifdef DEBUG_PASSWORD
  38         DEBUG(100,("SMBencrypt_hash: lm#, challenge, response\n"));
  39         dump_data(100, (const char *)p21, 16);
  40         dump_data(100, (const char *)c8, 8);
  41         dump_data(100, (const char *)p24, 24);
  42 #endif
  43 }
  44
  45 /*
  46    This implements the X/Open SMB password encryption
  47    It takes a password ('unix' string), a 8 byte "crypt key"
  48    and puts 24 bytes of encrypted password into p24
  49
  50    Returns False if password must have been truncated to create LM hash
  51 */
  52
  53 BOOL SMBencrypt(const char *passwd, const uchar *c8, uchar p24[24])
  54 {
  55         BOOL ret;
  56         uchar lm_hash[16];
  57
  58         ret = E_deshash(passwd, lm_hash);
  59         SMBencrypt_hash(lm_hash, c8, p24);
  60         return ret;
  61 }
  62
  63 /**
  64  * Creates the MD4 Hash of the users password in NT UNICODE.
  65  * @param passwd password in 'unix' charset.
  66  * @param p16 return password hashed with md4, caller allocated 16 byte buffer
  67  */
  68
  69 void E_md4hash(const char *passwd, uchar p16[16])
  70 {
  71         int len;
  72         smb_ucs2_t wpwd[129];
  73
  74         /* Password must be converted to NT unicode - null terminated. */
  75         push_ucs2(NULL, wpwd, (const char *)passwd, 256, STR_UNICODE|STR_NOALIGN|STR_TERMINATE);
  76         /* Calculate length in bytes */
  77         len = strlen_w(wpwd) * sizeof(int16);
  78
  79         mdfour(p16, (unsigned char *)wpwd, len);
  80         ZERO_STRUCT(wpwd);
  81 }
  82
  83 /**
  84  * Creates the MD5 Hash of a combination of 16 byte salt and 16 byte NT hash.
  85  * @param 16 byte salt.
  86  * @param 16 byte NT hash.
  87  * @param 16 byte return hashed with md5, caller allocated 16 byte buffer
  88  */
  89
  90 void E_md5hash(const uchar salt[16], const uchar nthash[16], uchar hash_out[16])
  91 {
  92         struct MD5Context tctx;
  93         uchar array[32];
  94
  95         memset(hash_out, '\0', 16);
  96         memcpy(array, salt, 16);
  97         memcpy(&array[16], nthash, 16);
  98         MD5Init(&tctx);
  99         MD5Update(&tctx, array, 32);
 100         MD5Final(hash_out, &tctx);
 101 }
 102
 103 /**
 104  * Creates the DES forward-only Hash of the users password in DOS ASCII charset
 105  * @param passwd password in 'unix' charset.
 106  * @param p16 return password hashed with DES, caller allocated 16 byte buffer
 107  * @return False if password was > 14 characters, and therefore may be incorrect, otherwise True
 108  * @note p16 is filled in regardless
 109  */
 110
 111 BOOL E_deshash(const char *passwd, uchar p16[16])
 112 {
 113         BOOL ret = True;
 114         fstring dospwd;
 115         ZERO_STRUCT(dospwd);
 116
 117         /* Password must be converted to DOS charset - null terminated, uppercase. */
 118         push_ascii(dospwd, passwd, sizeof(dospwd), STR_UPPER|STR_TERMINATE);
 119
 120         /* Only the fisrt 14 chars are considered, password need not be null terminated. */
 121         E_P16((const unsigned char *)dospwd, p16);
 122
 123         if (strlen(dospwd) > 14) {
 124                 ret = False;
 125         }
 126
 127         ZERO_STRUCT(dospwd);
 128
 129         return ret;
 130 }
 131
 132 /**
 133  * Creates the MD4 and DES (LM) Hash of the users password.
 134  * MD4 is of the NT Unicode, DES is of the DOS UPPERCASE password.
 135  * @param passwd password in 'unix' charset.
 136  * @param nt_p16 return password hashed with md4, caller allocated 16 byte buffer
 137  * @param p16 return password hashed with des, caller allocated 16 byte buffer
 138  */
 139
 140 /* Does both the NT and LM owfs of a user's password */
 141 void nt_lm_owf_gen(const char *pwd, uchar nt_p16[16], uchar p16[16])
 142 {
 143         /* Calculate the MD4 hash (NT compatible) of the password */
 144         memset(nt_p16, '\0', 16);
 145         E_md4hash(pwd, nt_p16);
 146
 147 #ifdef DEBUG_PASSWORD
 148         DEBUG(100,("nt_lm_owf_gen: pwd, nt#\n"));
 149         dump_data(120, pwd, strlen(pwd));
 150         dump_data(100, (char *)nt_p16, 16);
 151 #endif
 152
 153         E_deshash(pwd, (uchar *)p16);
 154
 155 #ifdef DEBUG_PASSWORD
 156         DEBUG(100,("nt_lm_owf_gen: pwd, lm#\n"));
 157         dump_data(120, pwd, strlen(pwd));
 158         dump_data(100, (char *)p16, 16);
 159 #endif
 160 }
 161
 162 /* Does both the NTLMv2 owfs of a user's password */
 163 BOOL ntv2_owf_gen(const uchar owf[16],
 164                   const char *user_in, const char *domain_in,
 165                   BOOL upper_case_domain, /* Transform the domain into UPPER case */
 166                   uchar kr_buf[16])
 167 {
 168         smb_ucs2_t *user;
 169         smb_ucs2_t *domain;
 170
 171         size_t user_byte_len;
 172         size_t domain_byte_len;
 173
 174         HMACMD5Context ctx;
 175
 176         user_byte_len = push_ucs2_allocate(&user, user_in);
 177         if (user_byte_len == (size_t)-1) {
 178                 DEBUG(0, ("push_uss2_allocate() for user returned -1 (probably malloc() failure)\n"));
 179                 return False;
 180         }
 181
 182         domain_byte_len = push_ucs2_allocate(&domain, domain_in);
 183         if (domain_byte_len == (size_t)-1) {
 184                 DEBUG(0, ("push_uss2_allocate() for domain returned -1 (probably malloc() failure)\n"));
 185                 SAFE_FREE(user);
 186                 return False;
 187         }
 188
 189         strupper_w(user);
 190
 191         if (upper_case_domain)
 192                 strupper_w(domain);
 193
 194         SMB_ASSERT(user_byte_len >= 2);
 195         SMB_ASSERT(domain_byte_len >= 2);
 196
 197         /* We don't want null termination */
 198         user_byte_len = user_byte_len - 2;
 199         domain_byte_len = domain_byte_len - 2;
 200
 201         hmac_md5_init_limK_to_64(owf, 16, &ctx);
 202         hmac_md5_update((const unsigned char *)user, user_byte_len, &ctx);
 203         hmac_md5_update((const unsigned char *)domain, domain_byte_len, &ctx);
 204         hmac_md5_final(kr_buf, &ctx);
 205
 206 #ifdef DEBUG_PASSWORD
 207         DEBUG(100, ("ntv2_owf_gen: user, domain, owfkey, kr\n"));
 208         dump_data(100, (const char *)user, user_byte_len);
 209         dump_data(100, (const char *)domain, domain_byte_len);
 210         dump_data(100, (const char *)owf, 16);
 211         dump_data(100, (const char *)kr_buf, 16);
 212 #endif
 213
 214         SAFE_FREE(user);
 215         SAFE_FREE(domain);
 216         return True;
 217 }
 218
 219 /* Does the des encryption from the NT or LM MD4 hash. */
 220 void SMBOWFencrypt(const uchar passwd[16], const uchar *c8, uchar p24[24])
 221 {
 222         uchar p21[21];
 223
 224         ZERO_STRUCT(p21);
 225
 226         memcpy(p21, passwd, 16);
 227         E_P24(p21, c8, p24);
 228 }
 229
 230 /* Does the des encryption from the FIRST 8 BYTES of the NT or LM MD4 hash. */
 231 void NTLMSSPOWFencrypt(const uchar passwd[8], const uchar *ntlmchalresp, uchar p24[24])
 232 {
 233         uchar p21[21];
 234
 235         memset(p21,'\0',21);
 236         memcpy(p21, passwd, 8);
 237         memset(p21 + 8, 0xbd, 8);
 238
 239         E_P24(p21, ntlmchalresp, p24);
 240 #ifdef DEBUG_PASSWORD
 241         DEBUG(100,("NTLMSSPOWFencrypt: p21, c8, p24\n"));
 242         dump_data(100, (char *)p21, 21);
 243         dump_data(100, (const char *)ntlmchalresp, 8);
 244         dump_data(100, (char *)p24, 24);
 245 #endif
 246 }
 247
 248
 249 /* Does the des encryption. */
 250
 251 void SMBNTencrypt_hash(const uchar nt_hash[16], uchar *c8, uchar *p24)
 252 {
 253         uchar p21[21];
 254
 255         memset(p21,'\0',21);
 256         memcpy(p21, nt_hash, 16);
 257         SMBOWFencrypt(p21, c8, p24);
 258
 259 #ifdef DEBUG_PASSWORD
 260         DEBUG(100,("SMBNTencrypt: nt#, challenge, response\n"));
 261         dump_data(100, (char *)p21, 16);
 262         dump_data(100, (char *)c8, 8);
 263         dump_data(100, (char *)p24, 24);
 264 #endif
 265 }
 266
 267 /* Does the NT MD4 hash then des encryption. Plaintext version of the above. */
 268
 269 void SMBNTencrypt(const char *passwd, uchar *c8, uchar *p24)
 270 {
 271         uchar nt_hash[16];
 272         E_md4hash(passwd, nt_hash);
 273         SMBNTencrypt_hash(nt_hash, c8, p24);
 274 }
 275
 276 /* Does the md5 encryption from the Key Response for NTLMv2. */
 277 void SMBOWFencrypt_ntv2(const uchar kr[16],
 278                         const DATA_BLOB *srv_chal,
 279                         const DATA_BLOB *cli_chal,
 280                         uchar resp_buf[16])
 281 {
 282         HMACMD5Context ctx;
 283
 284         hmac_md5_init_limK_to_64(kr, 16, &ctx);
 285         hmac_md5_update(srv_chal->data, srv_chal->length, &ctx);
 286         hmac_md5_update(cli_chal->data, cli_chal->length, &ctx);
 287         hmac_md5_final(resp_buf, &ctx);
 288
 289 #ifdef DEBUG_PASSWORD
 290         DEBUG(100, ("SMBOWFencrypt_ntv2: srv_chal, cli_chal, resp_buf\n"));
 291         dump_data(100, (const char *)srv_chal->data, srv_chal->length);
 292         dump_data(100, (const char *)cli_chal->data, cli_chal->length);
 293         dump_data(100, (const char *)resp_buf, 16);
 294 #endif
 295 }
 296
 297 void SMBsesskeygen_ntv2(const uchar kr[16],
 298                         const uchar * nt_resp, uint8 sess_key[16])
 299 {
 300         /* a very nice, 128 bit, variable session key */
 301
 302         HMACMD5Context ctx;
 303
 304         hmac_md5_init_limK_to_64(kr, 16, &ctx);
 305         hmac_md5_update(nt_resp, 16, &ctx);
 306         hmac_md5_final((unsigned char *)sess_key, &ctx);
 307
 308 #ifdef DEBUG_PASSWORD
 309         DEBUG(100, ("SMBsesskeygen_ntv2:\n"));
 310         dump_data(100, (const char *)sess_key, 16);
 311 #endif
 312 }
 313
 314 void SMBsesskeygen_ntv1(const uchar kr[16],
 315                         const uchar * nt_resp, uint8 sess_key[16])
 316 {
 317         /* yes, this session key does not change - yes, this
 318            is a problem - but it is 128 bits */
 319
 320         mdfour((unsigned char *)sess_key, kr, 16);
 321
 322 #ifdef DEBUG_PASSWORD
 323         DEBUG(100, ("SMBsesskeygen_ntv1:\n"));
 324         dump_data(100, (const char *)sess_key, 16);
 325 #endif
 326 }
 327
 328 void SMBsesskeygen_lm_sess_key(const uchar lm_hash[16],
 329                         const uchar lm_resp[24], /* only uses 8 */
 330                         uint8 sess_key[16])
 331 {
 332         uchar p24[24];
 333         uchar partial_lm_hash[16];
 334
 335         memcpy(partial_lm_hash, lm_hash, 8);
 336         memset(partial_lm_hash + 8, 0xbd, 8);
 337
 338         SMBOWFencrypt(partial_lm_hash, lm_resp, p24);
 339
 340         memcpy(sess_key, p24, 16);
 341
 342 #ifdef DEBUG_PASSWORD
 343         DEBUG(100, ("SMBsesskeygen_lmv1_jerry:\n"));
 344         dump_data(100, (const char *)sess_key, 16);
 345 #endif
 346 }
 347
 348 DATA_BLOB NTLMv2_generate_names_blob(const char *hostname,
 349                                      const char *domain)
 350 {
 351         DATA_BLOB names_blob = data_blob(NULL, 0);
 352
 353         msrpc_gen(&names_blob, "aaa",
 354                   NTLMSSP_NAME_TYPE_DOMAIN, domain,
 355                   NTLMSSP_NAME_TYPE_SERVER, hostname,
 356                   0, "");
 357         return names_blob;
 358 }
 359
 360 static DATA_BLOB NTLMv2_generate_client_data(const DATA_BLOB *names_blob)
 361 {
 362         uchar client_chal[8];
 363         DATA_BLOB response = data_blob(NULL, 0);
 364         char long_date[8];
 365
 366         generate_random_buffer(client_chal, sizeof(client_chal));
 367
 368         put_long_date(long_date, time(NULL));
 369
 370         /* See http://www.ubiqx.org/cifs/SMB.html#SMB.8.5 */
 371
 372         msrpc_gen(&response, "ddbbdb",
 373                   0x00000101,     /* Header  */
 374                   0,              /* 'Reserved'  */
 375                   long_date, 8,   /* Timestamp */
 376                   client_chal, 8, /* client challenge */
 377                   0,              /* Unknown */
 378                   names_blob->data, names_blob->length);        /* End of name list */
 379
 380         return response;
 381 }
 382
 383 static DATA_BLOB NTLMv2_generate_response(const uchar ntlm_v2_hash[16],
 384                                           const DATA_BLOB *server_chal,
 385                                           const DATA_BLOB *names_blob)
 386 {
 387         uchar ntlmv2_response[16];
 388         DATA_BLOB ntlmv2_client_data;
 389         DATA_BLOB final_response;
 390
 391         /* NTLMv2 */
 392         /* generate some data to pass into the response function - including
 393            the hostname and domain name of the server */
 394         ntlmv2_client_data = NTLMv2_generate_client_data(names_blob);
 395
 396         /* Given that data, and the challenge from the server, generate a response */
 397         SMBOWFencrypt_ntv2(ntlm_v2_hash, server_chal, &ntlmv2_client_data, ntlmv2_response);
 398
 399         final_response = data_blob(NULL, sizeof(ntlmv2_response) + ntlmv2_client_data.length);
 400
 401         memcpy(final_response.data, ntlmv2_response, sizeof(ntlmv2_response));
 402
 403         memcpy(final_response.data+sizeof(ntlmv2_response),
 404                ntlmv2_client_data.data, ntlmv2_client_data.length);
 405
 406         data_blob_free(&ntlmv2_client_data);
 407
 408         return final_response;
 409 }
 410
 411 static DATA_BLOB LMv2_generate_response(const uchar ntlm_v2_hash[16],
 412                                         const DATA_BLOB *server_chal)
 413 {
 414         uchar lmv2_response[16];
 415         DATA_BLOB lmv2_client_data = data_blob(NULL, 8);
 416         DATA_BLOB final_response = data_blob(NULL, 24);
 417
 418         /* LMv2 */
 419         /* client-supplied random data */
 420         generate_random_buffer(lmv2_client_data.data, lmv2_client_data.length);
 421
 422         /* Given that data, and the challenge from the server, generate a response */
 423         SMBOWFencrypt_ntv2(ntlm_v2_hash, server_chal, &lmv2_client_data, lmv2_response);
 424         memcpy(final_response.data, lmv2_response, sizeof(lmv2_response));
 425
 426         /* after the first 16 bytes is the random data we generated above,
 427            so the server can verify us with it */
 428         memcpy(final_response.data+sizeof(lmv2_response),
 429                lmv2_client_data.data, lmv2_client_data.length);
 430
 431         data_blob_free(&lmv2_client_data);
 432
 433         return final_response;
 434 }
 435
 436 BOOL SMBNTLMv2encrypt_hash(const char *user, const char *domain, const uchar nt_hash[16],
 437                       const DATA_BLOB *server_chal,
 438                       const DATA_BLOB *names_blob,
 439                       DATA_BLOB *lm_response, DATA_BLOB *nt_response,
 440                       DATA_BLOB *user_session_key)
 441 {
 442         uchar ntlm_v2_hash[16];
 443
 444         /* We don't use the NT# directly.  Instead we use it mashed up with
 445            the username and domain.
 446            This prevents username swapping during the auth exchange
 447         */
 448         if (!ntv2_owf_gen(nt_hash, user, domain, False, ntlm_v2_hash)) {
 449                 return False;
 450         }
 451
 452         if (nt_response) {
 453                 *nt_response = NTLMv2_generate_response(ntlm_v2_hash, server_chal,
 454                                                         names_blob);
 455                 if (user_session_key) {
 456                         *user_session_key = data_blob(NULL, 16);
 457
 458                         /* The NTLMv2 calculations also provide a session key, for signing etc later */
 459                         /* use only the first 16 bytes of nt_response for session key */
 460                         SMBsesskeygen_ntv2(ntlm_v2_hash, nt_response->data, user_session_key->data);
 461                 }
 462         }
 463
 464         /* LMv2 */
 465
 466         if (lm_response) {
 467                 *lm_response = LMv2_generate_response(ntlm_v2_hash, server_chal);
 468         }
 469
 470         return True;
 471 }
 472
 473 /* Plaintext version of the above. */
 474
 475 BOOL SMBNTLMv2encrypt(const char *user, const char *domain, const char *password,
 476                       const DATA_BLOB *server_chal,
 477                       const DATA_BLOB *names_blob,
 478                       DATA_BLOB *lm_response, DATA_BLOB *nt_response,
 479                       DATA_BLOB *user_session_key)
 480 {
 481         uchar nt_hash[16];
 482         E_md4hash(password, nt_hash);
 483
 484         return SMBNTLMv2encrypt_hash(user, domain, nt_hash,
 485                                 server_chal,
 486                                 names_blob,
 487                                 lm_response, nt_response,
 488                                 user_session_key);
 489 }
 490
 491 /***********************************************************
 492  encode a password buffer with a unicode password.  The buffer
 493  is filled with random data to make it harder to attack.
 494 ************************************************************/
 495 BOOL encode_pw_buffer(uint8 buffer[516], const char *password, int string_flags)
 496 {
 497         uchar new_pw[512];
 498         size_t new_pw_len;
 499
 500         /* the incoming buffer can be any alignment. */
 501         string_flags |= STR_NOALIGN;
 502
 503         new_pw_len = push_string(NULL, new_pw,
 504                                  password,
 505                                  sizeof(new_pw), string_flags);
 506
 507         memcpy(&buffer[512 - new_pw_len], new_pw, new_pw_len);
 508
 509         generate_random_buffer(buffer, 512 - new_pw_len);
 510
 511         /*
 512          * The length of the new password is in the last 4 bytes of
 513          * the data buffer.
 514          */
 515         SIVAL(buffer, 512, new_pw_len);
 516         ZERO_STRUCT(new_pw);
 517         return True;
 518 }
 519
 520
 521 /***********************************************************
 522  decode a password buffer
 523  *new_pw_len is the length in bytes of the possibly mulitbyte
 524  returned password including termination.
 525 ************************************************************/
 526
 527 BOOL decode_pw_buffer(uint8 in_buffer[516], char *new_pwrd,
 528                       int new_pwrd_size, uint32 *new_pw_len,
 529                       int string_flags)
 530 {
 531         int byte_len=0;
 532
 533         /* the incoming buffer can be any alignment. */
 534         string_flags |= STR_NOALIGN;
 535
 536         /*
 537           Warning !!! : This function is called from some rpc call.
 538           The password IN the buffer may be a UNICODE string.
 539           The password IN new_pwrd is an ASCII string
 540           If you reuse that code somewhere else check first.
 541         */
 542
 543         /* The length of the new password is in the last 4 bytes of the data buffer. */
 544
 545         byte_len = IVAL(in_buffer, 512);
 546
 547 #ifdef DEBUG_PASSWORD
 548         dump_data(100, (const char *)in_buffer, 516);
 549 #endif
 550
 551         /* Password cannot be longer than the size of the password buffer */
 552         if ( (byte_len < 0) || (byte_len > 512)) {
 553                 DEBUG(0, ("decode_pw_buffer: incorrect password length (%d).\n", byte_len));
 554                 DEBUG(0, ("decode_pw_buffer: check that 'encrypt passwords = yes'\n"));
 555                 return False;
 556         }
 557
 558         /* decode into the return buffer.  Buffer length supplied */
 559         *new_pw_len = pull_string(NULL, new_pwrd, &in_buffer[512 - byte_len], new_pwrd_size,
 560                                   byte_len, string_flags);
 561
 562 #ifdef DEBUG_PASSWORD
 563         DEBUG(100,("decode_pw_buffer: new_pwrd: "));
 564         dump_data(100, (const char *)new_pwrd, *new_pw_len);
 565         DEBUG(100,("multibyte len:%d\n", *new_pw_len));
 566         DEBUG(100,("original char len:%d\n", byte_len/2));
 567 #endif
 568
 569         return True;
 570 }
 571
 572 /***********************************************************
 573  Decode an arc4 encrypted password change buffer.
 574 ************************************************************/
 575
 576 void encode_or_decode_arc4_passwd_buffer(unsigned char pw_buf[532], const DATA_BLOB *psession_key)
 577 {
 578         struct MD5Context tctx;
 579         unsigned char key_out[16];
 580
 581         /* Confounder is last 16 bytes. */
 582
 583         MD5Init(&tctx);
 584         MD5Update(&tctx, &pw_buf[516], 16);
 585         MD5Update(&tctx, psession_key->data, psession_key->length);
 586         MD5Final(key_out, &tctx);
 587         /* arc4 with key_out. */
 588         SamOEMhash(pw_buf, key_out, 516);
 589 }
 590
 591 /***********************************************************
 592  Encrypt/Decrypt used for LSA secrets and trusted domain
 593  passwords.
 594 ************************************************************/
 595
 596 void sess_crypt_blob(DATA_BLOB *out, const DATA_BLOB *in, const DATA_BLOB *session_key, int forward)
 597 {
 598         int i, k;
 599
 600         for (i=0,k=0;
 601              i<in->length;
 602              i += 8, k += 7) {
 603                 uint8 bin[8], bout[8], key[7];
 604
 605                 memset(bin, 0, 8);
 606                 memcpy(bin,  &in->data[i], MIN(8, in->length-i));
 607
 608                 if (k + 7 > session_key->length) {
 609                         k = (session_key->length - k);
 610                 }
 611                 memcpy(key, &session_key->data[k], 7);
 612
 613                 des_crypt56(bout, bin, key, forward?1:0);
 614
 615                 memcpy(&out->data[i], bout, MIN(8, in->length-i));
 616         }
 617 }
 618
 619 /* Decrypts password-blob with session-key
 620  * @param pass          password for session-key
 621  * @param data_in       DATA_BLOB encrypted password
 622  *
 623  * Returns cleartext password in CH_UNIX
 624  * Caller must free the returned string
 625  */
 626
 627 char *decrypt_trustdom_secret(const char *pass, DATA_BLOB *data_in)
 628 {
 629         DATA_BLOB data_out, sess_key;
 630         uchar nt_hash[16];
 631         uint32_t length;
 632         uint32_t version;
 633         fstring cleartextpwd;
 634
 635         if (!data_in || !pass)
 636                 return NULL;
 637
 638         /* generate md4 password-hash derived from the NT UNICODE password */
 639         E_md4hash(pass, nt_hash);
 640
 641         /* hashed twice with md4 */
 642         mdfour(nt_hash, nt_hash, 16);
 643
 644         /* 16-Byte session-key */
 645         sess_key = data_blob(nt_hash, 16);
 646         if (sess_key.data == NULL)
 647                 return NULL;
 648
 649         data_out = data_blob(NULL, data_in->length);
 650         if (data_out.data == NULL)
 651                 return NULL;
 652
 653         /* decrypt with des3 */
 654         sess_crypt_blob(&data_out, data_in, &sess_key, 0);
 655
 656         /* 4 Byte length, 4 Byte version */
 657         length  = IVAL(data_out.data, 0);
 658         version = IVAL(data_out.data, 4);
 659
 660         if (length > data_in->length - 8) {
 661                 DEBUG(0,("decrypt_trustdom_secret: invalid length (%d)\n", length));
 662                 return NULL;
 663         }
 664
 665         if (version != 1) {
 666                 DEBUG(0,("decrypt_trustdom_secret: unknown version number (%d)\n", version));
 667                 return NULL;
 668         }
 669
 670         rpcstr_pull(cleartextpwd, data_out.data + 8, sizeof(fstring), length, 0 );
 671
 672 #ifdef DEBUG_PASSWORD
 673         DEBUG(100,("decrypt_trustdom_secret: length is: %d, version is: %d, password is: %s\n",
 674                                 length, version, cleartextpwd));
 675 #endif
 676
 677         data_blob_free(&data_out);
 678         data_blob_free(&sess_key);
 679
 680         return SMB_STRDUP(cleartextpwd);
 681
 682 }
 683