source3/libsmb/ntlmssp_sign.c

   1 /*
   2  *  Unix SMB/CIFS implementation.
   3  *  Version 3.0
   4  *  NTLMSSP Signing routines
   5  *  Copyright (C) Luke Kenneth Casson Leighton 1996-2001
   6  *  Copyright (C) Andrew Bartlett 2003
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software Foundation,
  20  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21  */
  22
  23 #include "includes.h"
  24
  25 #define CLI_SIGN "session key to client-to-server signing key magic constant"
  26 #define CLI_SEAL "session key to client-to-server sealing key magic constant"
  27 #define SRV_SIGN "session key to server-to-client signing key magic constant"
  28 #define SRV_SEAL "session key to server-to-client sealing key magic constant"
  29
  30 static void NTLMSSPcalc_ap( unsigned char *hash, unsigned char *data, int len)
  31 {
  32     unsigned char index_i = hash[256];
  33     unsigned char index_j = hash[257];
  34     int ind;
  35
  36     for (ind = 0; ind < len; ind++)
  37     {
  38         unsigned char tc;
  39         unsigned char t;
  40
  41         index_i++;
  42         index_j += hash[index_i];
  43
  44         tc = hash[index_i];
  45         hash[index_i] = hash[index_j];
  46         hash[index_j] = tc;
  47
  48         t = hash[index_i] + hash[index_j];
  49         data[ind] = data[ind] ^ hash[t];
  50     }
  51
  52     hash[256] = index_i;
  53     hash[257] = index_j;
  54 }
  55
  56 static void calc_hash(unsigned char *hash, const char *k2, int k2l)
  57 {
  58         unsigned char j = 0;
  59         int ind;
  60
  61         for (ind = 0; ind < 256; ind++)
  62         {
  63                 hash[ind] = (unsigned char)ind;
  64         }
  65
  66         for (ind = 0; ind < 256; ind++)
  67         {
  68                 unsigned char tc;
  69
  70                 j += (hash[ind] + k2[ind%k2l]);
  71
  72                 tc = hash[ind];
  73                 hash[ind] = hash[j];
  74                 hash[j] = tc;
  75         }
  76
  77         hash[256] = 0;
  78         hash[257] = 0;
  79 }
  80
  81 static void calc_ntlmv2_hash(unsigned char hash[16], char digest[16],
  82                              DATA_BLOB session_key,
  83                              const char *constant)
  84 {
  85         struct MD5Context ctx3;
  86
  87         /* NOTE:  This code is currently complate fantasy - it's
  88            got more in common with reality than the previous code
  89            (the LM session key is not the right thing to use) but
  90            it still needs work */
  91
  92         MD5Init(&ctx3);
  93         MD5Update(&ctx3, session_key.data, session_key.length);
  94         MD5Update(&ctx3, constant, strlen(constant));
  95         MD5Final(digest, &ctx3);
  96
  97         calc_hash(hash, digest, 16);
  98 }
  99
 100 enum ntlmssp_direction {
 101         NTLMSSP_SEND,
 102         NTLMSSP_RECEIVE
 103 };
 104
 105 static NTSTATUS ntlmssp_make_packet_signature(NTLMSSP_CLIENT_STATE *ntlmssp_state,
 106                                               const uchar *data, size_t length,
 107                                               enum ntlmssp_direction direction,
 108                                               DATA_BLOB *sig)
 109 {
 110         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 111                 HMACMD5Context ctx;
 112                 char seq_num[4];
 113                 uchar digest[16];
 114                 SIVAL(seq_num, 0, ntlmssp_state->ntlmssp_seq_num);
 115
 116                 hmac_md5_init_limK_to_64(ntlmssp_state->cli_sign_const, 16, &ctx);
 117                 hmac_md5_update(seq_num, 4, &ctx);
 118                 hmac_md5_update(data, length, &ctx);
 119                 hmac_md5_final(digest, &ctx);
 120
 121                 if (!msrpc_gen(sig, "dBd", NTLMSSP_SIGN_VERSION, digest, 8 /* only copy first 8 bytes */
 122                                , ntlmssp_state->ntlmssp_seq_num)) {
 123                         return NT_STATUS_NO_MEMORY;
 124                 }
 125                 switch (direction) {
 126                 case NTLMSSP_SEND:
 127                         NTLMSSPcalc_ap(ntlmssp_state->cli_sign_hash,  sig->data+4, sig->length-4);
 128                         break;
 129                 case NTLMSSP_RECEIVE:
 130                         NTLMSSPcalc_ap(ntlmssp_state->srv_sign_hash,  sig->data+4, sig->length-4);
 131                         break;
 132                 }
 133         } else {
 134                 uint32 crc;
 135                 crc = crc32_calc_buffer(data, length);
 136                 if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmssp_seq_num)) {
 137                         return NT_STATUS_NO_MEMORY;
 138                 }
 139
 140                 dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmssp_hash,
 141                              sizeof(ntlmssp_state->ntlmssp_hash));
 142                 NTLMSSPcalc_ap(ntlmssp_state->ntlmssp_hash, sig->data+4, sig->length-4);
 143         }
 144         return NT_STATUS_OK;
 145 }
 146
 147 NTSTATUS ntlmssp_client_sign_packet(NTLMSSP_CLIENT_STATE *ntlmssp_state,
 148                                            const uchar *data, size_t length,
 149                                            DATA_BLOB *sig)
 150 {
 151         NTSTATUS nt_status = ntlmssp_make_packet_signature(ntlmssp_state, data, length, NTLMSSP_SEND, sig);
 152
 153         /* increment counter on send */
 154         ntlmssp_state->ntlmssp_seq_num++;
 155         return nt_status;
 156 }
 157
 158 /**
 159  * Check the signature of an incoming packet
 160  * @note caller *must* check that the signature is the size it expects
 161  *
 162  */
 163
 164 NTSTATUS ntlmssp_client_check_packet(NTLMSSP_CLIENT_STATE *ntlmssp_state,
 165                                      const uchar *data, size_t length,
 166                                      const DATA_BLOB *sig)
 167 {
 168         DATA_BLOB local_sig;
 169         NTSTATUS nt_status;
 170
 171         if (sig->length < 8) {
 172                 DEBUG(0, ("NTLMSSP packet check failed due to short signature (%u bytes)!\n",
 173                           sig->length));
 174         }
 175
 176         nt_status = ntlmssp_make_packet_signature(ntlmssp_state, data,
 177                                                   length, NTLMSSP_RECEIVE, &local_sig);
 178
 179         if (!NT_STATUS_IS_OK(nt_status)) {
 180                 DEBUG(0, ("NTLMSSP packet check failed with %s\n", nt_errstr(nt_status)));
 181                 return nt_status;
 182         }
 183
 184         if (memcmp(sig->data+sig->length - 8, local_sig.data+local_sig.length - 8, 8) != 0) {
 185                 DEBUG(5, ("BAD SIG: wanted signature of\n"));
 186                 dump_data(5, local_sig.data, local_sig.length);
 187
 188                 DEBUG(5, ("BAD SIG: got signature of\n"));
 189                 dump_data(5, sig->data, sig->length);
 190
 191                 DEBUG(0, ("NTLMSSP packet check failed due to invalid signature!\n"));
 192                 return NT_STATUS_ACCESS_DENIED;
 193         }
 194
 195         /* increment counter on recieive */
 196         ntlmssp_state->ntlmssp_seq_num++;
 197
 198         return NT_STATUS_OK;
 199 }
 200
 201
 202 /**
 203  * Seal data with the NTLMSSP algorithm
 204  *
 205  */
 206
 207 NTSTATUS ntlmssp_client_seal_packet(NTLMSSP_CLIENT_STATE *ntlmssp_state,
 208                                     uchar *data, size_t length,
 209                                     DATA_BLOB *sig)
 210 {
 211         DEBUG(10,("ntlmssp_client_seal_data: seal\n"));
 212         dump_data_pw("ntlmssp clear data\n", data, length);
 213         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 214                 HMACMD5Context ctx;
 215                 char seq_num[4];
 216                 uchar digest[16];
 217                 SIVAL(seq_num, 0, ntlmssp_state->ntlmssp_seq_num);
 218
 219                 hmac_md5_init_limK_to_64(ntlmssp_state->cli_sign_const, 16, &ctx);
 220                 hmac_md5_update(seq_num, 4, &ctx);
 221                 hmac_md5_update(data, length, &ctx);
 222                 hmac_md5_final(digest, &ctx);
 223
 224                 if (!msrpc_gen(sig, "dBd", NTLMSSP_SIGN_VERSION, digest, 8 /* only copy first 8 bytes */
 225                                , ntlmssp_state->ntlmssp_seq_num)) {
 226                         return NT_STATUS_NO_MEMORY;
 227                 }
 228
 229                 dump_data_pw("ntlmssp client sealing hash:\n",
 230                              ntlmssp_state->cli_seal_hash,
 231                              sizeof(ntlmssp_state->cli_seal_hash));
 232                 NTLMSSPcalc_ap(ntlmssp_state->cli_seal_hash, data, length);
 233                 dump_data_pw("ntlmssp client signing hash:\n",
 234                              ntlmssp_state->cli_sign_hash,
 235                              sizeof(ntlmssp_state->cli_sign_hash));
 236                 NTLMSSPcalc_ap(ntlmssp_state->cli_sign_hash,  sig->data+4, sig->length-4);
 237         } else {
 238                 uint32 crc;
 239                 crc = crc32_calc_buffer(data, length);
 240                 if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmssp_seq_num)) {
 241                         return NT_STATUS_NO_MEMORY;
 242                 }
 243
 244                 /* The order of these two operations matters - we must first seal the packet,
 245                    then seal the sequence number - this is becouse the ntlmssp_hash is not
 246                    constant, but is is rather updated with each iteration */
 247
 248                 dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmssp_hash,
 249                              sizeof(ntlmssp_state->ntlmssp_hash));
 250                 NTLMSSPcalc_ap(ntlmssp_state->ntlmssp_hash, data, length);
 251
 252                 dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmssp_hash,
 253                              sizeof(ntlmssp_state->ntlmssp_hash));
 254                 NTLMSSPcalc_ap(ntlmssp_state->ntlmssp_hash, sig->data+4, sig->length-4);
 255         }
 256         dump_data_pw("ntlmssp sealed data\n", data, length);
 257
 258         /* increment counter on send */
 259         ntlmssp_state->ntlmssp_seq_num++;
 260
 261         return NT_STATUS_OK;
 262 }
 263
 264 /**
 265  * Unseal data with the NTLMSSP algorithm
 266  *
 267  */
 268
 269 NTSTATUS ntlmssp_client_unseal_packet(NTLMSSP_CLIENT_STATE *ntlmssp_state,
 270                                       uchar *data, size_t length,
 271                                       DATA_BLOB *sig)
 272 {
 273         DEBUG(10,("ntlmssp_client_unseal_data: seal\n"));
 274         dump_data_pw("ntlmssp sealed data\n", data, length);
 275         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 276                 NTLMSSPcalc_ap(ntlmssp_state->srv_seal_hash, data, length);
 277         } else {
 278                 dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmssp_hash,
 279                              sizeof(ntlmssp_state->ntlmssp_hash));
 280                 NTLMSSPcalc_ap(ntlmssp_state->ntlmssp_hash, data, length);
 281         }
 282         dump_data_pw("ntlmssp clear data\n", data, length);
 283
 284         return ntlmssp_client_check_packet(ntlmssp_state, data, length, sig);
 285 }
 286
 287 /**
 288    Initialise the state for NTLMSSP signing.
 289 */
 290 NTSTATUS ntlmssp_client_sign_init(NTLMSSP_CLIENT_STATE *ntlmssp_state)
 291 {
 292         unsigned char p24[24];
 293         ZERO_STRUCT(p24);
 294
 295         DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
 296         debug_ntlmssp_flags(ntlmssp_state->neg_flags);
 297
 298         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2)
 299         {
 300
 301                 calc_ntlmv2_hash(ntlmssp_state->cli_sign_hash,
 302                                  ntlmssp_state->cli_sign_const,
 303                                  ntlmssp_state->session_key, CLI_SIGN);
 304                 dump_data_pw("NTLMSSP client sign hash:\n",
 305                              ntlmssp_state->cli_sign_hash,
 306                              sizeof(ntlmssp_state->cli_sign_hash));
 307
 308                 calc_ntlmv2_hash(ntlmssp_state->cli_seal_hash,
 309                                  ntlmssp_state->cli_seal_const,
 310                                  ntlmssp_state->session_key, CLI_SEAL);
 311                 dump_data_pw("NTLMSSP client sesl hash:\n",
 312                              ntlmssp_state->cli_seal_hash,
 313                              sizeof(ntlmssp_state->cli_seal_hash));
 314
 315                 calc_ntlmv2_hash(ntlmssp_state->srv_sign_hash,
 316                                  ntlmssp_state->srv_sign_const,
 317                                  ntlmssp_state->session_key, SRV_SIGN);
 318                 dump_data_pw("NTLMSSP server sign hash:\n",
 319                              ntlmssp_state->srv_sign_hash,
 320                              sizeof(ntlmssp_state->srv_sign_hash));
 321
 322                 calc_ntlmv2_hash(ntlmssp_state->srv_seal_hash,
 323                                  ntlmssp_state->srv_seal_const,
 324                                  ntlmssp_state->session_key, SRV_SEAL);
 325                 dump_data_pw("NTLMSSP server seal hash:\n",
 326                              ntlmssp_state->cli_sign_hash,
 327                              sizeof(ntlmssp_state->cli_sign_hash));
 328         }
 329         else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) {
 330                 if (!ntlmssp_state->session_key.data || ntlmssp_state->session_key.length < 8) {
 331                         /* can't sign or check signatures yet */
 332                         DEBUG(5, ("NTLMSSP Sign/Seal - cannot use LM KEY yet\n"));
 333                         return NT_STATUS_UNSUCCESSFUL;
 334                 }
 335
 336                 DEBUG(5, ("NTLMSSP Sign/Seal - using LM KEY\n"));
 337
 338                 calc_hash(ntlmssp_state->ntlmssp_hash, ntlmssp_state->session_key.data, 8);
 339                 dump_data_pw("NTLMSSP hash:\n", ntlmssp_state->ntlmssp_hash,
 340                              sizeof(ntlmssp_state->ntlmssp_hash));
 341         } else {
 342                 if (!ntlmssp_state->session_key.data || ntlmssp_state->session_key.length < 16) {
 343                         /* can't sign or check signatures yet */
 344                         DEBUG(5, ("NTLMSSP Sign/Seal - cannot use NT KEY yet\n"));
 345                         return NT_STATUS_UNSUCCESSFUL;
 346                 }
 347
 348                 DEBUG(5, ("NTLMSSP Sign/Seal - using NT KEY\n"));
 349
 350                 calc_hash(ntlmssp_state->ntlmssp_hash, ntlmssp_state->session_key.data, 16);
 351                 dump_data_pw("NTLMSSP hash:\n", ntlmssp_state->ntlmssp_hash,
 352                              sizeof(ntlmssp_state->ntlmssp_hash));
 353         }
 354
 355         ntlmssp_state->ntlmssp_seq_num = 0;
 356
 357         return NT_STATUS_OK;
 358 }