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, p21, 16);
  40         dump_data(100, c8, 8);
  41         dump_data(100, 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, (uint8 *)pwd, strlen(pwd));
 150         dump_data(100, 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, (uint8 *)pwd, strlen(pwd));
 158         dump_data(100, 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                 return False;
 186         }
 187
 188         strupper_w(user);
 189
 190         if (upper_case_domain)
 191                 strupper_w(domain);
 192
 193         SMB_ASSERT(user_byte_len >= 2);
 194         SMB_ASSERT(domain_byte_len >= 2);
 195
 196         /* We don't want null termination */
 197         user_byte_len = user_byte_len - 2;
 198         domain_byte_len = domain_byte_len - 2;
 199
 200         hmac_md5_init_limK_to_64(owf, 16, &ctx);
 201         hmac_md5_update((const unsigned char *)user, user_byte_len, &ctx);
 202         hmac_md5_update((const unsigned char *)domain, domain_byte_len, &ctx);
 203         hmac_md5_final(kr_buf, &ctx);
 204
 205 #ifdef DEBUG_PASSWORD
 206         DEBUG(100, ("ntv2_owf_gen: user, domain, owfkey, kr\n"));
 207         dump_data(100, (uint8 *)user, user_byte_len);
 208         dump_data(100, (uint8 *)domain, domain_byte_len);
 209         dump_data(100, (uint8 *)owf, 16);
 210         dump_data(100, (uint8 *)kr_buf, 16);
 211 #endif
 212
 213         SAFE_FREE(user);
 214         SAFE_FREE(domain);
 215         return True;
 216 }
 217
 218 /* Does the des encryption from the NT or LM MD4 hash. */
 219 void SMBOWFencrypt(const uchar passwd[16], const uchar *c8, uchar p24[24])
 220 {
 221         uchar p21[21];
 222
 223         ZERO_STRUCT(p21);
 224
 225         memcpy(p21, passwd, 16);
 226         E_P24(p21, c8, p24);
 227 }
 228
 229 /* Does the des encryption from the FIRST 8 BYTES of the NT or LM MD4 hash. */
 230 void NTLMSSPOWFencrypt(const uchar passwd[8], const uchar *ntlmchalresp, uchar p24[24])
 231 {
 232         uchar p21[21];
 233
 234         memset(p21,'\0',21);
 235         memcpy(p21, passwd, 8);
 236         memset(p21 + 8, 0xbd, 8);
 237
 238         E_P24(p21, ntlmchalresp, p24);
 239 #ifdef DEBUG_PASSWORD
 240         DEBUG(100,("NTLMSSPOWFencrypt: p21, c8, p24\n"));
 241         dump_data(100, p21, 21);
 242         dump_data(100, ntlmchalresp, 8);
 243         dump_data(100, p24, 24);
 244 #endif
 245 }
 246
 247
 248 /* Does the des encryption. */
 249
 250 void SMBNTencrypt_hash(const uchar nt_hash[16], uchar *c8, uchar *p24)
 251 {
 252         uchar p21[21];
 253
 254         memset(p21,'\0',21);
 255         memcpy(p21, nt_hash, 16);
 256         SMBOWFencrypt(p21, c8, p24);
 257
 258 #ifdef DEBUG_PASSWORD
 259         DEBUG(100,("SMBNTencrypt: nt#, challenge, response\n"));
 260         dump_data(100, p21, 16);
 261         dump_data(100, c8, 8);
 262         dump_data(100, p24, 24);
 263 #endif
 264 }
 265
 266 /* Does the NT MD4 hash then des encryption. Plaintext version of the above. */
 267
 268 void SMBNTencrypt(const char *passwd, uchar *c8, uchar *p24)
 269 {
 270         uchar nt_hash[16];
 271         E_md4hash(passwd, nt_hash);
 272         SMBNTencrypt_hash(nt_hash, c8, p24);
 273 }
 274
 275 /* Does the md5 encryption from the Key Response for NTLMv2. */
 276 void SMBOWFencrypt_ntv2(const uchar kr[16],
 277                         const DATA_BLOB *srv_chal,
 278                         const DATA_BLOB *cli_chal,
 279                         uchar resp_buf[16])
 280 {
 281         HMACMD5Context ctx;
 282
 283         hmac_md5_init_limK_to_64(kr, 16, &ctx);
 284         hmac_md5_update(srv_chal->data, srv_chal->length, &ctx);
 285         hmac_md5_update(cli_chal->data, cli_chal->length, &ctx);
 286         hmac_md5_final(resp_buf, &ctx);
 287
 288 #ifdef DEBUG_PASSWORD
 289         DEBUG(100, ("SMBOWFencrypt_ntv2: srv_chal, cli_chal, resp_buf\n"));
 290         dump_data(100, srv_chal->data, srv_chal->length);
 291         dump_data(100, cli_chal->data, cli_chal->length);
 292         dump_data(100, resp_buf, 16);
 293 #endif
 294 }
 295
 296 void SMBsesskeygen_ntv2(const uchar kr[16],
 297                         const uchar * nt_resp, uint8 sess_key[16])
 298 {
 299         /* a very nice, 128 bit, variable session key */
 300
 301         HMACMD5Context ctx;
 302
 303         hmac_md5_init_limK_to_64(kr, 16, &ctx);
 304         hmac_md5_update(nt_resp, 16, &ctx);
 305         hmac_md5_final((unsigned char *)sess_key, &ctx);
 306
 307 #ifdef DEBUG_PASSWORD
 308         DEBUG(100, ("SMBsesskeygen_ntv2:\n"));
 309         dump_data(100, sess_key, 16);
 310 #endif
 311 }
 312
 313 void SMBsesskeygen_ntv1(const uchar kr[16],
 314                         const uchar * nt_resp, uint8 sess_key[16])
 315 {
 316         /* yes, this session key does not change - yes, this
 317            is a problem - but it is 128 bits */
 318
 319         mdfour((unsigned char *)sess_key, kr, 16);
 320
 321 #ifdef DEBUG_PASSWORD
 322         DEBUG(100, ("SMBsesskeygen_ntv1:\n"));
 323         dump_data(100, sess_key, 16);
 324 #endif
 325 }
 326
 327 void SMBsesskeygen_lm_sess_key(const uchar lm_hash[16],
 328                         const uchar lm_resp[24], /* only uses 8 */
 329                         uint8 sess_key[16])
 330 {
 331         uchar p24[24];
 332         uchar partial_lm_hash[16];
 333
 334         memcpy(partial_lm_hash, lm_hash, 8);
 335         memset(partial_lm_hash + 8, 0xbd, 8);
 336
 337         SMBOWFencrypt(partial_lm_hash, lm_resp, p24);
 338
 339         memcpy(sess_key, p24, 16);
 340
 341 #ifdef DEBUG_PASSWORD
 342         DEBUG(100, ("SMBsesskeygen_lmv1_jerry:\n"));
 343         dump_data(100, sess_key, 16);
 344 #endif
 345 }
 346
 347 DATA_BLOB NTLMv2_generate_names_blob(const char *hostname,
 348                                      const char *domain)
 349 {
 350         DATA_BLOB names_blob = data_blob_null;
 351
 352         msrpc_gen(&names_blob, "aaa",
 353                   NTLMSSP_NAME_TYPE_DOMAIN, domain,
 354                   NTLMSSP_NAME_TYPE_SERVER, hostname,
 355                   0, "");
 356         return names_blob;
 357 }
 358
 359 static DATA_BLOB NTLMv2_generate_client_data(const DATA_BLOB *names_blob)
 360 {
 361         uchar client_chal[8];
 362         DATA_BLOB response = data_blob_null;
 363         char long_date[8];
 364
 365         generate_random_buffer(client_chal, sizeof(client_chal));
 366
 367         put_long_date(long_date, time(NULL));
 368
 369         /* See http://www.ubiqx.org/cifs/SMB.html#SMB.8.5 */
 370
 371         msrpc_gen(&response, "ddbbdb",
 372                   0x00000101,     /* Header  */
 373                   0,              /* 'Reserved'  */
 374                   long_date, 8,   /* Timestamp */
 375                   client_chal, 8, /* client challenge */
 376                   0,              /* Unknown */
 377                   names_blob->data, names_blob->length);        /* End of name list */
 378
 379         return response;
 380 }
 381
 382 static DATA_BLOB NTLMv2_generate_response(const uchar ntlm_v2_hash[16],
 383                                           const DATA_BLOB *server_chal,
 384                                           const DATA_BLOB *names_blob)
 385 {
 386         uchar ntlmv2_response[16];
 387         DATA_BLOB ntlmv2_client_data;
 388         DATA_BLOB final_response;
 389
 390         /* NTLMv2 */
 391         /* generate some data to pass into the response function - including
 392            the hostname and domain name of the server */
 393         ntlmv2_client_data = NTLMv2_generate_client_data(names_blob);
 394
 395         /* Given that data, and the challenge from the server, generate a response */
 396         SMBOWFencrypt_ntv2(ntlm_v2_hash, server_chal, &ntlmv2_client_data, ntlmv2_response);
 397
 398         final_response = data_blob(NULL, sizeof(ntlmv2_response) + ntlmv2_client_data.length);
 399
 400         memcpy(final_response.data, ntlmv2_response, sizeof(ntlmv2_response));
 401
 402         memcpy(final_response.data+sizeof(ntlmv2_response),
 403                ntlmv2_client_data.data, ntlmv2_client_data.length);
 404
 405         data_blob_free(&ntlmv2_client_data);
 406
 407         return final_response;
 408 }
 409
 410 static DATA_BLOB LMv2_generate_response(const uchar ntlm_v2_hash[16],
 411                                         const DATA_BLOB *server_chal)
 412 {
 413         uchar lmv2_response[16];
 414         DATA_BLOB lmv2_client_data = data_blob(NULL, 8);
 415         DATA_BLOB final_response = data_blob(NULL, 24);
 416
 417         /* LMv2 */
 418         /* client-supplied random data */
 419         generate_random_buffer(lmv2_client_data.data, lmv2_client_data.length);
 420
 421         /* Given that data, and the challenge from the server, generate a response */
 422         SMBOWFencrypt_ntv2(ntlm_v2_hash, server_chal, &lmv2_client_data, lmv2_response);
 423         memcpy(final_response.data, lmv2_response, sizeof(lmv2_response));
 424
 425         /* after the first 16 bytes is the random data we generated above,
 426            so the server can verify us with it */
 427         memcpy(final_response.data+sizeof(lmv2_response),
 428                lmv2_client_data.data, lmv2_client_data.length);
 429
 430         data_blob_free(&lmv2_client_data);
 431
 432         return final_response;
 433 }
 434
 435 BOOL SMBNTLMv2encrypt_hash(const char *user, const char *domain, const uchar nt_hash[16],
 436                       const DATA_BLOB *server_chal,
 437                       const DATA_BLOB *names_blob,
 438                       DATA_BLOB *lm_response, DATA_BLOB *nt_response,
 439                       DATA_BLOB *user_session_key)
 440 {
 441         uchar ntlm_v2_hash[16];
 442
 443         /* We don't use the NT# directly.  Instead we use it mashed up with
 444            the username and domain.
 445            This prevents username swapping during the auth exchange
 446         */
 447         if (!ntv2_owf_gen(nt_hash, user, domain, True, ntlm_v2_hash)) {
 448                 return False;
 449         }
 450
 451         if (nt_response) {
 452                 *nt_response = NTLMv2_generate_response(ntlm_v2_hash, server_chal,
 453                                                         names_blob);
 454                 if (user_session_key) {
 455                         *user_session_key = data_blob(NULL, 16);
 456
 457                         /* The NTLMv2 calculations also provide a session key, for signing etc later */
 458                         /* use only the first 16 bytes of nt_response for session key */
 459                         SMBsesskeygen_ntv2(ntlm_v2_hash, nt_response->data, user_session_key->data);
 460                 }
 461         }
 462
 463         /* LMv2 */
 464
 465         if (lm_response) {
 466                 *lm_response = LMv2_generate_response(ntlm_v2_hash, server_chal);
 467         }
 468
 469         return True;
 470 }
 471
 472 /* Plaintext version of the above. */
 473
 474 BOOL SMBNTLMv2encrypt(const char *user, const char *domain, const char *password,
 475                       const DATA_BLOB *server_chal,
 476                       const DATA_BLOB *names_blob,
 477                       DATA_BLOB *lm_response, DATA_BLOB *nt_response,
 478                       DATA_BLOB *user_session_key)
 479 {
 480         uchar nt_hash[16];
 481         E_md4hash(password, nt_hash);
 482
 483         return SMBNTLMv2encrypt_hash(user, domain, nt_hash,
 484                                 server_chal,
 485                                 names_blob,
 486                                 lm_response, nt_response,
 487                                 user_session_key);
 488 }
 489
 490 /***********************************************************
 491  encode a password buffer with a unicode password.  The buffer
 492  is filled with random data to make it harder to attack.
 493 ************************************************************/
 494 BOOL encode_pw_buffer(uint8 buffer[516], const char *password, int string_flags)
 495 {
 496         uchar new_pw[512];
 497         size_t new_pw_len;
 498
 499         /* the incoming buffer can be any alignment. */
 500         string_flags |= STR_NOALIGN;
 501
 502         new_pw_len = push_string(NULL, new_pw,
 503                                  password,
 504                                  sizeof(new_pw), string_flags);
 505
 506         memcpy(&buffer[512 - new_pw_len], new_pw, new_pw_len);
 507
 508         generate_random_buffer(buffer, 512 - new_pw_len);
 509
 510         /*
 511          * The length of the new password is in the last 4 bytes of
 512          * the data buffer.
 513          */
 514         SIVAL(buffer, 512, new_pw_len);
 515         ZERO_STRUCT(new_pw);
 516         return True;
 517 }
 518
 519
 520 /***********************************************************
 521  decode a password buffer
 522  *new_pw_len is the length in bytes of the possibly mulitbyte
 523  returned password including termination.
 524 ************************************************************/
 525
 526 BOOL decode_pw_buffer(uint8 in_buffer[516], char *new_pwrd,
 527                       int new_pwrd_size, uint32 *new_pw_len,
 528                       int string_flags)
 529 {
 530         int byte_len=0;
 531
 532         /* the incoming buffer can be any alignment. */
 533         string_flags |= STR_NOALIGN;
 534
 535         /*
 536           Warning !!! : This function is called from some rpc call.
 537           The password IN the buffer may be a UNICODE string.
 538           The password IN new_pwrd is an ASCII string
 539           If you reuse that code somewhere else check first.
 540         */
 541
 542         /* The length of the new password is in the last 4 bytes of the data buffer. */
 543
 544         byte_len = IVAL(in_buffer, 512);
 545
 546 #ifdef DEBUG_PASSWORD
 547         dump_data(100, in_buffer, 516);
 548 #endif
 549
 550         /* Password cannot be longer than the size of the password buffer */
 551         if ( (byte_len < 0) || (byte_len > 512)) {
 552                 DEBUG(0, ("decode_pw_buffer: incorrect password length (%d).\n", byte_len));
 553                 DEBUG(0, ("decode_pw_buffer: check that 'encrypt passwords = yes'\n"));
 554                 return False;
 555         }
 556
 557         /* decode into the return buffer.  Buffer length supplied */
 558         *new_pw_len = pull_string(NULL, 0, new_pwrd,
 559                                   &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, (uint8 *)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