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                              const char encrypted_response[16],
  83                              const char *constant)
  84 {
  85         struct MD5Context ctx3;
  86
  87         MD5Init(&ctx3);
  88         MD5Update(&ctx3, encrypted_response, 5);
  89         MD5Update(&ctx3, constant, strlen(constant));
  90         MD5Final(digest, &ctx3);
  91
  92         calc_hash(hash, digest, 16);
  93 }
  94
  95 enum ntlmssp_direction {
  96         NTLMSSP_SEND,
  97         NTLMSSP_RECEIVE
  98 };
  99
 100 static NTSTATUS ntlmssp_make_packet_signiture(NTLMSSP_CLIENT_STATE *ntlmssp_state,
 101                                               const uchar *data, size_t length,
 102                                               enum ntlmssp_direction direction,
 103                                               DATA_BLOB *sig)
 104 {
 105         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 106                 HMACMD5Context ctx;
 107                 char seq_num[4];
 108                 uchar digest[16];
 109                 SIVAL(seq_num, 0, ntlmssp_state->ntlmssp_seq_num);
 110
 111                 hmac_md5_init_limK_to_64(ntlmssp_state->cli_sign_const, 16, &ctx);
 112                 hmac_md5_update(seq_num, 4, &ctx);
 113                 hmac_md5_update(data, length, &ctx);
 114                 hmac_md5_final(digest, &ctx);
 115
 116                 if (!msrpc_gen(sig, "Bd", digest, sizeof(digest), ntlmssp_state->ntlmssp_seq_num)) {
 117                         return NT_STATUS_NO_MEMORY;
 118                 }
 119                 switch (direction) {
 120                 case NTLMSSP_SEND:
 121                         NTLMSSPcalc_ap(ntlmssp_state->cli_sign_hash,  sig->data, sig->length);
 122                         break;
 123                 case NTLMSSP_RECEIVE:
 124                         NTLMSSPcalc_ap(ntlmssp_state->cli_sign_hash,  sig->data, sig->length);
 125                         break;
 126                 }
 127         } else {
 128                 uint32 crc;
 129                 crc = crc32_calc_buffer(data, length);
 130                 if (!msrpc_gen(sig, "ddd", 0, crc, ntlmssp_state->ntlmssp_seq_num)) {
 131                         return NT_STATUS_NO_MEMORY;
 132                 }
 133
 134                 NTLMSSPcalc_ap(ntlmssp_state->ntlmssp_hash, sig->data, sig->length);
 135         }
 136         return NT_STATUS_OK;
 137 }
 138
 139 NTSTATUS ntlmssp_client_sign_packet(NTLMSSP_CLIENT_STATE *ntlmssp_state,
 140                                            const uchar *data, size_t length,
 141                                            DATA_BLOB *sig)
 142 {
 143         ntlmssp_state->ntlmssp_seq_num++;
 144         return ntlmssp_make_packet_signiture(ntlmssp_state, data, length, NTLMSSP_SEND, sig);
 145 }
 146
 147 /**
 148  * Check the signature of an incoming packet
 149  * @note caller *must* check that the signature is the size it expects
 150  *
 151  */
 152
 153 NTSTATUS ntlmssp_client_check_packet(NTLMSSP_CLIENT_STATE *ntlmssp_state,
 154                                            const uchar *data, size_t length,
 155                                            const DATA_BLOB *sig)
 156 {
 157         DATA_BLOB local_sig;
 158         NTSTATUS nt_status;
 159
 160         if (sig->length < 8) {
 161                 DEBUG(0, ("NTLMSSP packet check failed due to short signiture (%u bytes)!\n",
 162                           sig->length));
 163         }
 164
 165         nt_status = ntlmssp_make_packet_signiture(ntlmssp_state, data,
 166                                                   length, NTLMSSP_RECEIVE, &local_sig);
 167
 168         if (!NT_STATUS_IS_OK(nt_status)) {
 169                 DEBUG(0, ("NTLMSSP packet check failed with %s\n", nt_errstr(nt_status)));
 170                 return nt_status;
 171         }
 172
 173         if (memcmp(sig->data, local_sig.data, MIN(sig->length, local_sig.length)) == 0) {
 174                 return NT_STATUS_OK;
 175         } else {
 176                 DEBUG(5, ("BAD SIG: wanted signature of\n"));
 177                 dump_data(5, local_sig.data, local_sig.length);
 178
 179                 DEBUG(5, ("BAD SIG: got signature of\n"));
 180                 dump_data(5, sig->data, sig->length);
 181
 182                 DEBUG(0, ("NTLMSSP packet check failed due to invalid signiture!\n"));
 183                 return NT_STATUS_ACCESS_DENIED;
 184         }
 185 }
 186
 187 /**
 188    Initialise the state for NTLMSSP signing.
 189 */
 190 NTSTATUS ntlmssp_client_sign_init(NTLMSSP_CLIENT_STATE *ntlmssp_state)
 191 {
 192         unsigned char p24[24];
 193         unsigned char lm_hash[16];
 194
 195         if (!ntlmssp_state->lm_resp.data) {
 196                 /* can't sign or check signitures yet */
 197                 return NT_STATUS_UNSUCCESSFUL;
 198         }
 199
 200         E_deshash(ntlmssp_state->password, lm_hash);
 201
 202         NTLMSSPOWFencrypt(lm_hash, ntlmssp_state->lm_resp.data, p24);
 203
 204         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2)
 205         {
 206                 calc_ntlmv2_hash(ntlmssp_state->cli_sign_hash, ntlmssp_state->cli_sign_const, p24, CLI_SIGN);
 207                 calc_ntlmv2_hash(ntlmssp_state->cli_seal_hash, ntlmssp_state->cli_seal_const, p24, CLI_SEAL);
 208                 calc_ntlmv2_hash(ntlmssp_state->srv_sign_hash, ntlmssp_state->srv_sign_const, p24, SRV_SIGN);
 209                 calc_ntlmv2_hash(ntlmssp_state->srv_seal_hash, ntlmssp_state->srv_seal_const, p24, SRV_SEAL);
 210         }
 211         else
 212         {
 213                 char k2[8];
 214                 memcpy(k2, p24, 5);
 215                 k2[5] = 0xe5;
 216                 k2[6] = 0x38;
 217                 k2[7] = 0xb0;
 218
 219                 calc_hash(ntlmssp_state->ntlmssp_hash, k2, 8);
 220         }
 221
 222         ntlmssp_state->ntlmssp_seq_num = 0;
 223
 224         ZERO_STRUCT(lm_hash);
 225         return NT_STATUS_OK;
 226 }