source4/auth/credentials/credentials_ntlm.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    User credentials handling
   5
   6    Copyright (C) Andrew Tridgell      2001
   7    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2001-2005
   8    Copyright (C) Stefan Metzmacher 2005
   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 "lib/ldb/include/ldb.h"
  27 #include "librpc/gen_ndr/ndr_samr.h" /* for struct samrPassword */
  28 #include "lib/crypto/crypto.h"
  29
  30 void cli_credentials_get_ntlm_username_domain(struct cli_credentials *cred, TALLOC_CTX *mem_ctx,
  31                                               const char **username,
  32                                               const char **domain)
  33 {
  34         if (cred->principal_obtained > cred->username_obtained) {
  35                 *domain = talloc_strdup(mem_ctx, "");
  36                 *username = cli_credentials_get_principal(cred, mem_ctx);
  37         } else {
  38                 *domain = cli_credentials_get_domain(cred);
  39                 *username = cli_credentials_get_username(cred);
  40         }
  41 }
  42
  43 NTSTATUS cli_credentials_get_ntlm_response(struct cli_credentials *cred, TALLOC_CTX *mem_ctx,
  44                                            int *flags,
  45                                            DATA_BLOB challenge, DATA_BLOB target_info,
  46                                            DATA_BLOB *_lm_response, DATA_BLOB *_nt_response,
  47                                            DATA_BLOB *_lm_session_key, DATA_BLOB *_session_key)
  48 {
  49         const char *user, *domain;
  50         DATA_BLOB lm_response, nt_response;
  51         DATA_BLOB lm_session_key, session_key;
  52         const struct samr_Password *nt_hash;
  53         lm_session_key = data_blob(NULL, 0);
  54
  55         nt_hash = cli_credentials_get_nt_hash(cred, mem_ctx);
  56
  57         cli_credentials_get_ntlm_username_domain(cred, mem_ctx, &user, &domain);
  58
  59         /* If we are sending a username@realm login (see function
  60          * above), then we will not send LM, it will not be
  61          * accepted */
  62         if (cred->principal_obtained > cred->username_obtained) {
  63                 *flags = *flags & ~CLI_CRED_LANMAN_AUTH;
  64         }
  65
  66         /* Likewise if we are a machine account (avoid protocol downgrade attacks) */
  67         if (cred->machine_account) {
  68                 *flags = *flags & ~CLI_CRED_LANMAN_AUTH;
  69         }
  70
  71         if (!nt_hash) {
  72                 static const uint8_t zeros[16];
  73                 /* do nothing - blobs are zero length */
  74
  75                 /* session key is all zeros */
  76                 session_key = data_blob_talloc(mem_ctx, zeros, 16);
  77                 lm_session_key = data_blob_talloc(mem_ctx, zeros, 16);
  78
  79                 lm_response = data_blob(NULL, 0);
  80                 nt_response = data_blob(NULL, 0);
  81
  82                 /* not doing NTLM2 without a password */
  83                 *flags &= ~CLI_CRED_NTLM2;
  84         } else if (*flags & CLI_CRED_NTLMv2_AUTH) {
  85
  86                 if (!target_info.length) {
  87                         /* be lazy, match win2k - we can't do NTLMv2 without it */
  88                         DEBUG(1, ("Server did not provide 'target information', required for NTLMv2\n"));
  89                         return NT_STATUS_INVALID_PARAMETER;
  90                 }
  91
  92                 /* TODO: if the remote server is standalone, then we should replace 'domain'
  93                    with the server name as supplied above */
  94
  95                 if (!SMBNTLMv2encrypt_hash(mem_ctx,
  96                                            user,
  97                                            domain,
  98                                            nt_hash->hash, &challenge,
  99                                            &target_info,
 100                                            &lm_response, &nt_response,
 101                                            NULL, &session_key)) {
 102                         return NT_STATUS_NO_MEMORY;
 103                 }
 104
 105                 /* LM Key is incompatible... */
 106                 *flags &= ~CLI_CRED_LANMAN_AUTH;
 107         } else if (*flags & CLI_CRED_NTLM2) {
 108                 struct MD5Context md5_session_nonce_ctx;
 109                 uint8_t session_nonce[16];
 110                 uint8_t session_nonce_hash[16];
 111                 uint8_t user_session_key[16];
 112
 113                 lm_response = data_blob_talloc(mem_ctx, NULL, 24);
 114                 generate_random_buffer(lm_response.data, 8);
 115                 memset(lm_response.data+8, 0, 16);
 116
 117                 memcpy(session_nonce, challenge.data, 8);
 118                 memcpy(&session_nonce[8], lm_response.data, 8);
 119
 120                 MD5Init(&md5_session_nonce_ctx);
 121                 MD5Update(&md5_session_nonce_ctx, challenge.data, 8);
 122                 MD5Update(&md5_session_nonce_ctx, lm_response.data, 8);
 123                 MD5Final(session_nonce_hash, &md5_session_nonce_ctx);
 124
 125                 DEBUG(5, ("NTLMSSP challenge set by NTLM2\n"));
 126                 DEBUG(5, ("challenge is: \n"));
 127                 dump_data(5, session_nonce_hash, 8);
 128
 129                 nt_response = data_blob_talloc(mem_ctx, NULL, 24);
 130                 SMBOWFencrypt(nt_hash->hash,
 131                               session_nonce_hash,
 132                               nt_response.data);
 133
 134                 session_key = data_blob_talloc(mem_ctx, NULL, 16);
 135
 136                 SMBsesskeygen_ntv1(nt_hash->hash, user_session_key);
 137                 hmac_md5(user_session_key, session_nonce, sizeof(session_nonce), session_key.data);
 138                 dump_data_pw("NTLM2 session key:\n", session_key.data, session_key.length);
 139
 140                 /* LM Key is incompatible... */
 141                 *flags &= ~CLI_CRED_LANMAN_AUTH;
 142         } else {
 143                 nt_response = data_blob_talloc(mem_ctx, NULL, 24);
 144                 SMBOWFencrypt(nt_hash->hash, challenge.data,
 145                               nt_response.data);
 146
 147                 session_key = data_blob_talloc(mem_ctx, NULL, 16);
 148                 SMBsesskeygen_ntv1(nt_hash->hash, session_key.data);
 149                 dump_data_pw("NT session key:\n", session_key.data, session_key.length);
 150
 151                 /* lanman auth is insecure, it may be disabled.
 152                    We may also not have a password */
 153                 if (*flags & CLI_CRED_LANMAN_AUTH) {
 154                         const char *password;
 155                         password = cli_credentials_get_password(cred);
 156                         if (!password) {
 157                                 lm_response = nt_response;
 158                         } else {
 159                                 uint8_t lm_hash[16];
 160                                 lm_response = data_blob_talloc(mem_ctx, NULL, 24);
 161                                 if (!SMBencrypt(password,challenge.data,
 162                                                 lm_response.data)) {
 163                                         /* If the LM password was too long (and therefore the LM hash being
 164                                            of the first 14 chars only), don't send it.
 165
 166                                            We don't have any better options but to send the NT response
 167                                         */
 168                                         data_blob_free(&lm_response);
 169                                         lm_response = nt_response;
 170                                         /* LM Key is incompatible with 'long' passwords */
 171                                         *flags &= ~CLI_CRED_LANMAN_AUTH;
 172                                 } else {
 173                                         E_deshash(password, lm_hash);
 174                                         lm_session_key = data_blob_talloc(mem_ctx, NULL, 16);
 175                                         memcpy(lm_session_key.data, lm_hash, 8);
 176                                         memset(&lm_session_key.data[8], '\0', 8);
 177
 178                                         if (!(*flags & CLI_CRED_NTLM_AUTH)) {
 179                                                 session_key = lm_session_key;
 180                                         }
 181                                 }
 182                         }
 183                 } else {
 184                         /* LM Key is incompatible... */
 185                         lm_response = nt_response;
 186                         *flags &= ~CLI_CRED_LANMAN_AUTH;
 187                 }
 188         }
 189         if (_lm_response) {
 190                 *_lm_response = lm_response;
 191         }
 192         if (_nt_response) {
 193                 *_nt_response = nt_response;
 194         }
 195         if (_lm_session_key) {
 196                 *_lm_session_key = lm_session_key;
 197         }
 198         if (_session_key) {
 199                 *_session_key = session_key;
 200         }
 201         return NT_STATUS_OK;
 202 }
 203