libcli/auth/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 3 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, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include "system/time.h"
  26 #include "auth/ntlmssp/ntlmssp.h"
  27 #include "auth/ntlmssp/msrpc_parse.h"
  28 #include "../lib/crypto/crypto.h"
  29 #include "libcli/auth/libcli_auth.h"
  30
  31 /*
  32    This implements the X/Open SMB password encryption
  33    It takes a password ('unix' string), a 8 byte "crypt key"
  34    and puts 24 bytes of encrypted password into p24
  35
  36    Returns false if password must have been truncated to create LM hash
  37 */
  38 bool SMBencrypt(const char *passwd, const uint8_t *c8, uint8_t p24[24])
  39 {
  40         bool ret;
  41         uint8_t p21[21];
  42
  43         memset(p21,'\0',21);
  44         ret = E_deshash(passwd, p21);
  45
  46         SMBOWFencrypt(p21, c8, p24);
  47
  48 #ifdef DEBUG_PASSWORD
  49         DEBUG(100,("SMBencrypt: lm#, challenge, response\n"));
  50         dump_data(100, p21, 16);
  51         dump_data(100, c8, 8);
  52         dump_data(100, p24, 24);
  53 #endif
  54
  55         return ret;
  56 }
  57
  58 /**
  59  * Creates the MD4 Hash of the users password in NT UNICODE.
  60  * @param passwd password in 'unix' charset.
  61  * @param p16 return password hashed with md4, caller allocated 16 byte buffer
  62  */
  63
  64 bool E_md4hash(const char *passwd, uint8_t p16[16])
  65 {
  66         size_t len;
  67         smb_ucs2_t *wpwd;
  68         bool ret;
  69
  70         ret = push_ucs2_talloc(NULL, &wpwd, passwd, &len);
  71         if (!ret || len < 2) {
  72                 /* We don't want to return fixed data, as most callers
  73                  * don't check */
  74                 mdfour(p16, (const uint8_t *)passwd, strlen(passwd));
  75                 return false;
  76         }
  77
  78         len -= 2;
  79         mdfour(p16, (const uint8_t *)wpwd, len);
  80
  81         talloc_free(wpwd);
  82         return true;
  83 }
  84
  85 /**
  86  * Creates the DES forward-only Hash of the users password in DOS ASCII charset
  87  * @param passwd password in 'unix' charset.
  88  * @param p16 return password hashed with DES, caller allocated 16 byte buffer
  89  * @return false if password was > 14 characters, and therefore may be incorrect, otherwise true
  90  * @note p16 is filled in regardless
  91  */
  92
  93 bool E_deshash(const char *passwd, uint8_t p16[16])
  94 {
  95         bool ret = true;
  96         char dospwd[256];
  97         ZERO_STRUCT(dospwd);
  98
  99         /* Password must be converted to DOS charset - null terminated, uppercase. */
 100         push_string(dospwd, passwd, sizeof(dospwd), STR_ASCII|STR_UPPER|STR_TERMINATE);
 101
 102         /* Only the first 14 chars are considered, password need not be null terminated. */
 103         E_P16((const uint8_t *)dospwd, p16);
 104
 105         if (strlen(dospwd) > 14) {
 106                 ret = false;
 107         }
 108
 109         ZERO_STRUCT(dospwd);
 110
 111         return ret;
 112 }
 113
 114 /* Does both the NTLMv2 owfs of a user's password */
 115 bool ntv2_owf_gen(const uint8_t owf[16],
 116                   const char *user_in, const char *domain_in,
 117                   bool upper_case_domain, /* Transform the domain into UPPER case */
 118                   uint8_t kr_buf[16])
 119 {
 120         smb_ucs2_t *user;
 121         smb_ucs2_t *domain;
 122         size_t user_byte_len;
 123         size_t domain_byte_len;
 124         bool ret;
 125
 126         HMACMD5Context ctx;
 127         TALLOC_CTX *mem_ctx = talloc_init("ntv2_owf_gen for %s\\%s", domain_in, user_in);
 128
 129         if (!mem_ctx) {
 130                 return false;
 131         }
 132
 133         if (!user_in) {
 134                 user_in = "";
 135         }
 136
 137         if (!domain_in) {
 138                 domain_in = "";
 139         }
 140
 141         user_in = strupper_talloc(mem_ctx, user_in);
 142         if (user_in == NULL) {
 143                 talloc_free(mem_ctx);
 144                 return false;
 145         }
 146
 147         if (upper_case_domain) {
 148                 domain_in = strupper_talloc(mem_ctx, domain_in);
 149                 if (domain_in == NULL) {
 150                         talloc_free(mem_ctx);
 151                         return false;
 152                 }
 153         }
 154
 155         ret = push_ucs2_talloc(mem_ctx, &user, user_in, &user_byte_len );
 156         if (!ret) {
 157                 DEBUG(0, ("push_uss2_talloc() for user returned -1 (probably talloc() failure)\n"));
 158                 talloc_free(mem_ctx);
 159                 return false;
 160         }
 161
 162         ret = push_ucs2_talloc(mem_ctx, &domain, domain_in, &domain_byte_len);
 163         if (!ret) {
 164                 DEBUG(0, ("push_ucs2_talloc() for domain returned -1 (probably talloc() failure)\n"));
 165                 talloc_free(mem_ctx);
 166                 return false;
 167         }
 168
 169         SMB_ASSERT(user_byte_len >= 2);
 170         SMB_ASSERT(domain_byte_len >= 2);
 171
 172         /* We don't want null termination */
 173         user_byte_len = user_byte_len - 2;
 174         domain_byte_len = domain_byte_len - 2;
 175
 176         hmac_md5_init_limK_to_64(owf, 16, &ctx);
 177         hmac_md5_update((const void *)user, user_byte_len, &ctx);
 178         hmac_md5_update((const void *)domain, domain_byte_len, &ctx);
 179         hmac_md5_final(kr_buf, &ctx);
 180
 181 #ifdef DEBUG_PASSWORD
 182         DEBUG(100, ("ntv2_owf_gen: user, domain, owfkey, kr\n"));
 183         dump_data(100, (const void *)user, user_byte_len);
 184         dump_data(100, (const void *)domain, domain_byte_len);
 185         dump_data(100, owf, 16);
 186         dump_data(100, kr_buf, 16);
 187 #endif
 188
 189         talloc_free(mem_ctx);
 190         return true;
 191 }
 192
 193 /* Does the des encryption from the NT or LM MD4 hash. */
 194 void SMBOWFencrypt(const uint8_t passwd[16], const uint8_t *c8, uint8_t p24[24])
 195 {
 196         uint8_t p21[21];
 197
 198         ZERO_STRUCT(p21);
 199
 200         memcpy(p21, passwd, 16);
 201         E_P24(p21, c8, p24);
 202 }
 203
 204 /* Does the NT MD4 hash then des encryption. */
 205
 206 void SMBNTencrypt(const char *passwd, uint8_t *c8, uint8_t *p24)
 207 {
 208         uint8_t p21[21];
 209
 210         memset(p21,'\0',21);
 211
 212         E_md4hash(passwd, p21);
 213         SMBOWFencrypt(p21, c8, p24);
 214
 215 #ifdef DEBUG_PASSWORD
 216         DEBUG(100,("SMBNTencrypt: nt#, challenge, response\n"));
 217         dump_data(100, p21, 16);
 218         dump_data(100, c8, 8);
 219         dump_data(100, p24, 24);
 220 #endif
 221 }
 222
 223 /* Does the md5 encryption from the Key Response for NTLMv2. */
 224 void SMBOWFencrypt_ntv2(const uint8_t kr[16],
 225                         const DATA_BLOB *srv_chal,
 226                         const DATA_BLOB *smbcli_chal,
 227                         uint8_t resp_buf[16])
 228 {
 229         HMACMD5Context ctx;
 230
 231         hmac_md5_init_limK_to_64(kr, 16, &ctx);
 232         hmac_md5_update(srv_chal->data, srv_chal->length, &ctx);
 233         hmac_md5_update(smbcli_chal->data, smbcli_chal->length, &ctx);
 234         hmac_md5_final(resp_buf, &ctx);
 235
 236 #ifdef DEBUG_PASSWORD
 237         DEBUG(100, ("SMBOWFencrypt_ntv2: srv_chal, smbcli_chal, resp_buf\n"));
 238         dump_data(100, srv_chal->data, srv_chal->length);
 239         dump_data(100, smbcli_chal->data, smbcli_chal->length);
 240         dump_data(100, resp_buf, 16);
 241 #endif
 242 }
 243
 244 void SMBsesskeygen_ntv2(const uint8_t kr[16],
 245                         const uint8_t * nt_resp, uint8_t sess_key[16])
 246 {
 247         /* a very nice, 128 bit, variable session key */
 248
 249         HMACMD5Context ctx;
 250
 251         hmac_md5_init_limK_to_64(kr, 16, &ctx);
 252         hmac_md5_update(nt_resp, 16, &ctx);
 253         hmac_md5_final((uint8_t *)sess_key, &ctx);
 254
 255 #ifdef DEBUG_PASSWORD
 256         DEBUG(100, ("SMBsesskeygen_ntv2:\n"));
 257         dump_data(100, sess_key, 16);
 258 #endif
 259 }
 260
 261 void SMBsesskeygen_ntv1(const uint8_t kr[16], uint8_t sess_key[16])
 262 {
 263         /* yes, this session key does not change - yes, this
 264            is a problem - but it is 128 bits */
 265
 266         mdfour((uint8_t *)sess_key, kr, 16);
 267
 268 #ifdef DEBUG_PASSWORD
 269         DEBUG(100, ("SMBsesskeygen_ntv1:\n"));
 270         dump_data(100, sess_key, 16);
 271 #endif
 272 }
 273
 274 void SMBsesskeygen_lm_sess_key(const uint8_t lm_hash[16],
 275                                const uint8_t lm_resp[24], /* only uses 8 */
 276                                uint8_t sess_key[16])
 277 {
 278         /* Calculate the LM session key (effective length 40 bits,
 279            but changes with each session) */
 280         uint8_t p24[24];
 281         uint8_t partial_lm_hash[14];
 282
 283         memcpy(partial_lm_hash, lm_hash, 8);
 284         memset(partial_lm_hash + 8, 0xbd, 6);
 285
 286         des_crypt56(p24,   lm_resp, partial_lm_hash,     1);
 287         des_crypt56(p24+8, lm_resp, partial_lm_hash + 7, 1);
 288
 289         memcpy(sess_key, p24, 16);
 290
 291 #ifdef DEBUG_PASSWORD
 292         DEBUG(100, ("SMBsesskeygen_lm_sess_key: \n"));
 293         dump_data(100, sess_key, 16);
 294 #endif
 295 }
 296
 297 DATA_BLOB NTLMv2_generate_names_blob(TALLOC_CTX *mem_ctx,
 298                                      const char *hostname,
 299                                      const char *domain)
 300 {
 301         DATA_BLOB names_blob = data_blob_talloc(mem_ctx, NULL, 0);
 302
 303         msrpc_gen(mem_ctx, &names_blob,
 304                   "aaa",
 305                   NTLMSSP_NAME_TYPE_DOMAIN, domain,
 306                   NTLMSSP_NAME_TYPE_SERVER, hostname,
 307                   0, "");
 308         return names_blob;
 309 }
 310
 311 static DATA_BLOB NTLMv2_generate_client_data(TALLOC_CTX *mem_ctx, const DATA_BLOB *names_blob)
 312 {
 313         uint8_t client_chal[8];
 314         DATA_BLOB response = data_blob(NULL, 0);
 315         uint8_t long_date[8];
 316         NTTIME nttime;
 317
 318         unix_to_nt_time(&nttime, time(NULL));
 319
 320         generate_random_buffer(client_chal, sizeof(client_chal));
 321
 322         push_nttime(long_date, 0, nttime);
 323
 324         /* See http://www.ubiqx.org/cifs/SMB.html#SMB.8.5 */
 325
 326         msrpc_gen(mem_ctx, &response, "ddbbdb",
 327                   0x00000101,     /* Header  */
 328                   0,              /* 'Reserved'  */
 329                   long_date, 8,   /* Timestamp */
 330                   client_chal, 8, /* client challenge */
 331                   0,              /* Unknown */
 332                   names_blob->data, names_blob->length);        /* End of name list */
 333
 334         return response;
 335 }
 336
 337 static DATA_BLOB NTLMv2_generate_response(TALLOC_CTX *out_mem_ctx,
 338                                           const uint8_t ntlm_v2_hash[16],
 339                                           const DATA_BLOB *server_chal,
 340                                           const DATA_BLOB *names_blob)
 341 {
 342         uint8_t ntlmv2_response[16];
 343         DATA_BLOB ntlmv2_client_data;
 344         DATA_BLOB final_response;
 345
 346         TALLOC_CTX *mem_ctx = talloc_named(out_mem_ctx, 0,
 347                                            "NTLMv2_generate_response internal context");
 348
 349         if (!mem_ctx) {
 350                 return data_blob(NULL, 0);
 351         }
 352
 353         /* NTLMv2 */
 354         /* generate some data to pass into the response function - including
 355            the hostname and domain name of the server */
 356         ntlmv2_client_data = NTLMv2_generate_client_data(mem_ctx, names_blob);
 357
 358         /* Given that data, and the challenge from the server, generate a response */
 359         SMBOWFencrypt_ntv2(ntlm_v2_hash, server_chal, &ntlmv2_client_data, ntlmv2_response);
 360
 361         final_response = data_blob_talloc(out_mem_ctx, NULL, sizeof(ntlmv2_response) + ntlmv2_client_data.length);
 362
 363         memcpy(final_response.data, ntlmv2_response, sizeof(ntlmv2_response));
 364
 365         memcpy(final_response.data+sizeof(ntlmv2_response),
 366                ntlmv2_client_data.data, ntlmv2_client_data.length);
 367
 368         talloc_free(mem_ctx);
 369
 370         return final_response;
 371 }
 372
 373 static DATA_BLOB LMv2_generate_response(TALLOC_CTX *mem_ctx,
 374                                         const uint8_t ntlm_v2_hash[16],
 375                                         const DATA_BLOB *server_chal)
 376 {
 377         uint8_t lmv2_response[16];
 378         DATA_BLOB lmv2_client_data = data_blob_talloc(mem_ctx, NULL, 8);
 379         DATA_BLOB final_response = data_blob_talloc(mem_ctx, NULL,24);
 380
 381         /* LMv2 */
 382         /* client-supplied random data */
 383         generate_random_buffer(lmv2_client_data.data, lmv2_client_data.length);
 384
 385         /* Given that data, and the challenge from the server, generate a response */
 386         SMBOWFencrypt_ntv2(ntlm_v2_hash, server_chal, &lmv2_client_data, lmv2_response);
 387         memcpy(final_response.data, lmv2_response, sizeof(lmv2_response));
 388
 389         /* after the first 16 bytes is the random data we generated above,
 390            so the server can verify us with it */
 391         memcpy(final_response.data+sizeof(lmv2_response),
 392                lmv2_client_data.data, lmv2_client_data.length);
 393
 394         data_blob_free(&lmv2_client_data);
 395
 396         return final_response;
 397 }
 398
 399 bool SMBNTLMv2encrypt_hash(TALLOC_CTX *mem_ctx,
 400                            const char *user, const char *domain, const uint8_t nt_hash[16],
 401                            const DATA_BLOB *server_chal,
 402                            const DATA_BLOB *names_blob,
 403                            DATA_BLOB *lm_response, DATA_BLOB *nt_response,
 404                            DATA_BLOB *lm_session_key, DATA_BLOB *user_session_key)
 405 {
 406         uint8_t ntlm_v2_hash[16];
 407
 408         /* We don't use the NT# directly.  Instead we use it mashed up with
 409            the username and domain.
 410            This prevents username swapping during the auth exchange
 411         */
 412         if (!ntv2_owf_gen(nt_hash, user, domain, true, ntlm_v2_hash)) {
 413                 return false;
 414         }
 415
 416         if (nt_response) {
 417                 *nt_response = NTLMv2_generate_response(mem_ctx,
 418                                                         ntlm_v2_hash, server_chal,
 419                                                         names_blob);
 420                 if (user_session_key) {
 421                         *user_session_key = data_blob_talloc(mem_ctx, NULL, 16);
 422
 423                         /* The NTLMv2 calculations also provide a session key, for signing etc later */
 424                         /* use only the first 16 bytes of nt_response for session key */
 425                         SMBsesskeygen_ntv2(ntlm_v2_hash, nt_response->data, user_session_key->data);
 426                 }
 427         }
 428
 429         /* LMv2 */
 430
 431         if (lm_response) {
 432                 *lm_response = LMv2_generate_response(mem_ctx,
 433                                                       ntlm_v2_hash, server_chal);
 434                 if (lm_session_key) {
 435                         *lm_session_key = data_blob_talloc(mem_ctx, NULL, 16);
 436
 437                         /* The NTLMv2 calculations also provide a session key, for signing etc later */
 438                         /* use only the first 16 bytes of lm_response for session key */
 439                         SMBsesskeygen_ntv2(ntlm_v2_hash, lm_response->data, lm_session_key->data);
 440                 }
 441         }
 442
 443         return true;
 444 }
 445
 446 bool SMBNTLMv2encrypt(TALLOC_CTX *mem_ctx,
 447                       const char *user, const char *domain,
 448                       const char *password,
 449                       const DATA_BLOB *server_chal,
 450                       const DATA_BLOB *names_blob,
 451                       DATA_BLOB *lm_response, DATA_BLOB *nt_response,
 452                       DATA_BLOB *lm_session_key, DATA_BLOB *user_session_key)
 453 {
 454         uint8_t nt_hash[16];
 455         E_md4hash(password, nt_hash);
 456
 457         return SMBNTLMv2encrypt_hash(mem_ctx,
 458                                      user, domain, nt_hash, server_chal, names_blob,
 459                                      lm_response, nt_response, lm_session_key, user_session_key);
 460 }
 461
 462 /***********************************************************
 463  encode a password buffer with a unicode password.  The buffer
 464  is filled with random data to make it harder to attack.
 465 ************************************************************/
 466 bool encode_pw_buffer(uint8_t buffer[516], const char *password, int string_flags)
 467 {
 468         uint8_t new_pw[512];
 469         size_t new_pw_len;
 470
 471         /* the incoming buffer can be any alignment. */
 472         string_flags |= STR_NOALIGN;
 473
 474         new_pw_len = push_string(new_pw,
 475                                  password,
 476                                  sizeof(new_pw), string_flags);
 477
 478         memcpy(&buffer[512 - new_pw_len], new_pw, new_pw_len);
 479
 480         generate_random_buffer(buffer, 512 - new_pw_len);
 481
 482         /*
 483          * The length of the new password is in the last 4 bytes of
 484          * the data buffer.
 485          */
 486         SIVAL(buffer, 512, new_pw_len);
 487         ZERO_STRUCT(new_pw);
 488         return true;
 489 }
 490
 491
 492 /***********************************************************
 493  decode a password buffer
 494  *new_pw_len is the length in bytes of the possibly mulitbyte
 495  returned password including termination.
 496 ************************************************************/
 497 bool decode_pw_buffer(uint8_t in_buffer[516], char *new_pwrd,
 498                       int new_pwrd_size, int string_flags)
 499 {
 500         int byte_len=0;
 501         ssize_t converted_pw_len;
 502
 503         /* the incoming buffer can be any alignment. */
 504         string_flags |= STR_NOALIGN;
 505
 506         /*
 507           Warning !!! : This function is called from some rpc call.
 508           The password IN the buffer may be a UNICODE string.
 509           The password IN new_pwrd is an ASCII string
 510           If you reuse that code somewhere else check first.
 511         */
 512
 513         /* The length of the new password is in the last 4 bytes of the data buffer. */
 514
 515         byte_len = IVAL(in_buffer, 512);
 516
 517 #ifdef DEBUG_PASSWORD
 518         dump_data(100, in_buffer, 516);
 519 #endif
 520
 521         /* Password cannot be longer than the size of the password buffer */
 522         if ( (byte_len < 0) || (byte_len > 512)) {
 523                 return false;
 524         }
 525
 526         /* decode into the return buffer.  Buffer length supplied */
 527         converted_pw_len = pull_string(new_pwrd, &in_buffer[512 - byte_len], new_pwrd_size,
 528                                   byte_len, string_flags);
 529
 530         if (converted_pw_len == -1) {
 531                 return false;
 532         }
 533
 534 #ifdef DEBUG_PASSWORD
 535         DEBUG(100,("decode_pw_buffer: new_pwrd: "));
 536         dump_data(100, (const uint8_t *)new_pwrd, converted_pw_len);
 537         DEBUG(100,("multibyte len:%d\n", (int)converted_pw_len));
 538         DEBUG(100,("original char len:%d\n", byte_len/2));
 539 #endif
 540
 541         return true;
 542 }
 543
 544 /***********************************************************
 545  encode a password buffer with an already unicode password.  The
 546  rest of the buffer is filled with random data to make it harder to attack.
 547 ************************************************************/
 548 bool set_pw_in_buffer(uint8_t buffer[516], DATA_BLOB *password)
 549 {
 550         if (password->length > 512) {
 551                 return false;
 552         }
 553
 554         memcpy(&buffer[512 - password->length], password->data, password->length);
 555
 556         generate_random_buffer(buffer, 512 - password->length);
 557
 558         /*
 559          * The length of the new password is in the last 4 bytes of
 560          * the data buffer.
 561          */
 562         SIVAL(buffer, 512, password->length);
 563         return true;
 564 }
 565
 566 /***********************************************************
 567  decode a password buffer
 568  *new_pw_size is the length in bytes of the extracted unicode password
 569 ************************************************************/
 570 bool extract_pw_from_buffer(TALLOC_CTX *mem_ctx,
 571                             uint8_t in_buffer[516], DATA_BLOB *new_pass)
 572 {
 573         int byte_len=0;
 574
 575         /* The length of the new password is in the last 4 bytes of the data buffer. */
 576
 577         byte_len = IVAL(in_buffer, 512);
 578
 579 #ifdef DEBUG_PASSWORD
 580         dump_data(100, in_buffer, 516);
 581 #endif
 582
 583         /* Password cannot be longer than the size of the password buffer */
 584         if ( (byte_len < 0) || (byte_len > 512)) {
 585                 return false;
 586         }
 587
 588         *new_pass = data_blob_talloc(mem_ctx, &in_buffer[512 - byte_len], byte_len);
 589
 590         if (!new_pass->data) {
 591                 return false;
 592         }
 593
 594         return true;
 595 }