source/auth/auth_server.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    Authenticate to a remote server
   5    Copyright (C) Andrew Tridgell 1992-1998
   6    Copyright (C) Andrew Bartlett 2001
   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
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 extern pstring global_myname;
  26 extern userdom_struct current_user_info;
  27
  28 /****************************************************************************
  29  Support for server level security.
  30 ****************************************************************************/
  31
  32 static struct cli_state *server_cryptkey(void)
  33 {
  34         struct cli_state *cli = NULL;
  35         fstring desthost;
  36         struct in_addr dest_ip;
  37         char *p, *pserver;
  38         BOOL connected_ok = False;
  39
  40         if (!(cli = cli_initialise(cli)))
  41                 return NULL;
  42
  43         /* security = server just can't function with spnego */
  44         cli->use_spnego = False;
  45
  46         pserver = strdup(lp_passwordserver());
  47         p = pserver;
  48
  49         while(next_token( &p, desthost, LIST_SEP, sizeof(desthost))) {
  50                 standard_sub_basic(current_user_info.smb_name, desthost);
  51                 strupper(desthost);
  52
  53                 if(!resolve_name( desthost, &dest_ip, 0x20)) {
  54                         DEBUG(1,("server_cryptkey: Can't resolve address for %s\n",desthost));
  55                         continue;
  56                 }
  57
  58                 if (ismyip(dest_ip)) {
  59                         DEBUG(1,("Password server loop - disabling password server %s\n",desthost));
  60                         continue;
  61                 }
  62
  63                 if (cli_connect(cli, desthost, &dest_ip)) {
  64                         DEBUG(3,("connected to password server %s\n",desthost));
  65                         connected_ok = True;
  66                         break;
  67                 }
  68         }
  69
  70         SAFE_FREE(pserver);
  71
  72         if (!connected_ok) {
  73                 DEBUG(0,("password server not available\n"));
  74                 cli_shutdown(cli);
  75                 return NULL;
  76         }
  77
  78         if (!attempt_netbios_session_request(cli, global_myname, desthost, &dest_ip))
  79                 return NULL;
  80
  81         if (strequal(desthost,myhostname())) {
  82                 exit_server("Password server loop!");
  83         }
  84
  85         DEBUG(3,("got session\n"));
  86
  87         if (!cli_negprot(cli)) {
  88                 DEBUG(1,("%s rejected the negprot\n",desthost));
  89                 cli_shutdown(cli);
  90                 return NULL;
  91         }
  92
  93         if (cli->protocol < PROTOCOL_LANMAN2 ||
  94             !(cli->sec_mode & 1)) {
  95                 DEBUG(1,("%s isn't in user level security mode\n",desthost));
  96                 cli_shutdown(cli);
  97                 return NULL;
  98         }
  99
 100         DEBUG(3,("password server OK\n"));
 101
 102         return cli;
 103 }
 104
 105 /****************************************************************************
 106  Clean up our allocated cli.
 107 ****************************************************************************/
 108
 109 static void free_server_private_data(void **private_data_pointer)
 110 {
 111         struct cli_state **cli = (struct cli_state **)private_data_pointer;
 112         if (*cli && (*cli)->initialised) {
 113                 cli_shutdown(*cli);
 114         }
 115 }
 116
 117 /****************************************************************************
 118  Send a 'keepalive' packet down the cli pipe.
 119 ****************************************************************************/
 120
 121 static void send_server_keepalive(void **private_data_pointer)
 122 {
 123         struct cli_state **cli = (struct cli_state **)private_data_pointer;
 124
 125         /* also send a keepalive to the password server if its still
 126            connected */
 127         if (cli && *cli && (*cli)->initialised) {
 128                 if (!send_keepalive((*cli)->fd)) {
 129                         DEBUG( 2, ( "password server keepalive failed.\n"));
 130                         cli_shutdown(*cli);
 131                 }
 132         }
 133 }
 134
 135 /****************************************************************************
 136  Get the challenge out of a password server.
 137 ****************************************************************************/
 138
 139 static DATA_BLOB auth_get_challenge_server(void **my_private_data, const struct authsupplied_info *auth_info)
 140 {
 141         struct cli_state *cli = server_cryptkey();
 142
 143         if (cli) {
 144                 DEBUG(3,("using password server validation\n"));
 145                 if ((cli->sec_mode & 2) == 0) {
 146                         /* We can't work with unencrypted password servers
 147                            unless 'encrypt passwords = no' */
 148                         DEBUG(5,("make_auth_info_server: Server is unencrypted, no challenge available..\n"));
 149
 150                         *my_private_data = (void *)cli;
 151                         return data_blob(NULL, 0);
 152
 153                 } else if (cli->secblob.length < 8) {
 154                         /* We can't do much if we don't get a full challenge */
 155                         DEBUG(2,("make_auth_info_server: Didn't receive a full challenge from server\n"));
 156                         cli_shutdown(cli);
 157                         return data_blob(NULL, 0);
 158                 }
 159
 160                 *my_private_data = (void *)cli;
 161
 162                 return data_blob(cli->secblob.data,8);
 163         } else {
 164                 return data_blob(NULL, 0);
 165         }
 166 }
 167
 168
 169 /****************************************************************************
 170  Check for a valid username and password in security=server mode.
 171   - Validate a password with the password server.
 172 ****************************************************************************/
 173
 174 static NTSTATUS check_smbserver_security(void *my_private_data,
 175                                   const auth_usersupplied_info *user_info,
 176                                   const auth_authsupplied_info *auth_info,
 177                                   auth_serversupplied_info **server_info)
 178 {
 179         struct cli_state *cli;
 180         static unsigned char badpass[24];
 181         static fstring baduser;
 182         static BOOL tested_password_server = False;
 183         static BOOL bad_password_server = False;
 184         NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;
 185         BOOL locally_made_cli = False;
 186
 187         /*
 188          * Check that the requested domain is not our own machine name.
 189          * If it is, we should never check the PDC here, we use our own local
 190          * password file.
 191          */
 192
 193         if(is_netbios_alias_or_name(user_info->domain.str)) {
 194                 DEBUG(3,("check_smbserver_security: Requested domain was for this machine.\n"));
 195                 return NT_STATUS_LOGON_FAILURE;
 196         }
 197
 198         cli = my_private_data;
 199
 200         if (cli) {
 201         } else {
 202                 cli = server_cryptkey();
 203                 locally_made_cli = True;
 204         }
 205
 206         if (!cli || !cli->initialised) {
 207                 DEBUG(1,("password server %s is not connected\n", cli->desthost));
 208                 return NT_STATUS_LOGON_FAILURE;
 209         }
 210
 211         if ((cli->sec_mode & 2) == 0) {
 212                 if (user_info->encrypted) {
 213                         DEBUG(1,("password server %s is plaintext, but we are encrypted. This just can't work :-(\n", cli->desthost));
 214                         return NT_STATUS_LOGON_FAILURE;
 215                 }
 216         } else {
 217                 if (memcmp(cli->secblob.data, auth_info->challenge.data, 8) != 0) {
 218                         DEBUG(1,("the challenge that the password server (%s) supplied us is not the one we gave our client. This just can't work :-(\n", cli->desthost));
 219                         return NT_STATUS_LOGON_FAILURE;
 220                 }
 221         }
 222
 223         if(badpass[0] == 0)
 224                 memset(badpass, 0x1f, sizeof(badpass));
 225
 226         if((user_info->nt_resp.length == sizeof(badpass)) &&
 227            !memcmp(badpass, user_info->nt_resp.data, sizeof(badpass))) {
 228                 /*
 229                  * Very unlikely, our random bad password is the same as the users
 230                  * password.
 231                  */
 232                 memset(badpass, badpass[0]+1, sizeof(badpass));
 233         }
 234
 235         if(baduser[0] == 0) {
 236                 fstrcpy(baduser, INVALID_USER_PREFIX);
 237                 fstrcat(baduser, global_myname);
 238         }
 239
 240         /*
 241          * Attempt a session setup with a totally incorrect password.
 242          * If this succeeds with the guest bit *NOT* set then the password
 243          * server is broken and is not correctly setting the guest bit. We
 244          * need to detect this as some versions of NT4.x are broken. JRA.
 245          */
 246
 247         /* I sure as hell hope that there arn't servers out there that take
 248          * NTLMv2 and have this bug, as we don't test for that...
 249          *  - abartlet@samba.org
 250          */
 251
 252         if ((!tested_password_server) && (lp_paranoid_server_security())) {
 253                 if (cli_session_setup(cli, baduser, (char *)badpass, sizeof(badpass),
 254                                         (char *)badpass, sizeof(badpass), user_info->domain.str)) {
 255
 256                         /*
 257                          * We connected to the password server so we
 258                          * can say we've tested it.
 259                          */
 260                         tested_password_server = True;
 261
 262                         if ((SVAL(cli->inbuf,smb_vwv2) & 1) == 0) {
 263                                 DEBUG(0,("server_validate: password server %s allows users as non-guest \
 264 with a bad password.\n", cli->desthost));
 265                                 DEBUG(0,("server_validate: This is broken (and insecure) behaviour. Please do not \
 266 use this machine as the password server.\n"));
 267                                 cli_ulogoff(cli);
 268
 269                                 /*
 270                                  * Password server has the bug.
 271                                  */
 272                                 bad_password_server = True;
 273                                 return NT_STATUS_LOGON_FAILURE;
 274                         }
 275                         cli_ulogoff(cli);
 276                 }
 277         } else {
 278
 279                 /*
 280                  * We have already tested the password server.
 281                  * Fail immediately if it has the bug.
 282                  */
 283
 284                 if(bad_password_server) {
 285                         DEBUG(0,("server_validate: [1] password server %s allows users as non-guest \
 286 with a bad password.\n", cli->desthost));
 287                         DEBUG(0,("server_validate: [1] This is broken (and insecure) behaviour. Please do not \
 288 use this machine as the password server.\n"));
 289                         return NT_STATUS_LOGON_FAILURE;
 290                 }
 291         }
 292
 293         /*
 294          * Now we know the password server will correctly set the guest bit, or is
 295          * not guest enabled, we can try with the real password.
 296          */
 297
 298         if (!user_info->encrypted) {
 299                 /* Plaintext available */
 300                 if (!cli_session_setup(cli, user_info->smb_name.str,
 301                                        (char *)user_info->plaintext_password.data,
 302                                        user_info->plaintext_password.length,
 303                                        NULL, 0,
 304                                        user_info->domain.str)) {
 305                         DEBUG(1,("password server %s rejected the password\n", cli->desthost));
 306                         /* Make this cli_nt_error() when the conversion is in */
 307                         nt_status = cli_nt_error(cli);
 308                 } else {
 309                         nt_status = NT_STATUS_OK;
 310                 }
 311         } else {
 312                 if (!cli_session_setup(cli, user_info->smb_name.str,
 313                                        (char *)user_info->lm_resp.data,
 314                                        user_info->lm_resp.length,
 315                                        (char *)user_info->nt_resp.data,
 316                                        user_info->nt_resp.length,
 317                                        user_info->domain.str)) {
 318                         DEBUG(1,("password server %s rejected the password\n", cli->desthost));
 319                         /* Make this cli_nt_error() when the conversion is in */
 320                         nt_status = cli_nt_error(cli);
 321                 } else {
 322                         nt_status = NT_STATUS_OK;
 323                 }
 324         }
 325
 326         /* if logged in as guest then reject */
 327         if ((SVAL(cli->inbuf,smb_vwv2) & 1) != 0) {
 328                 DEBUG(1,("password server %s gave us guest only\n", cli->desthost));
 329                 nt_status = NT_STATUS_LOGON_FAILURE;
 330         }
 331
 332         cli_ulogoff(cli);
 333
 334         if NT_STATUS_IS_OK(nt_status) {
 335                 struct passwd *pass = Get_Pwnam(user_info->internal_username.str);
 336                 if (pass) {
 337                         if (!make_server_info_pw(server_info, pass)) {
 338                                 nt_status = NT_STATUS_NO_MEMORY;
 339                         }
 340                 } else {
 341                         nt_status = NT_STATUS_NO_SUCH_USER;
 342                 }
 343         }
 344
 345         if (locally_made_cli) {
 346                 cli_shutdown(cli);
 347         }
 348
 349         return(nt_status);
 350 }
 351
 352 BOOL auth_init_smbserver(auth_methods **auth_method)
 353 {
 354         if (!make_auth_methods(auth_method)) {
 355                 return False;
 356         }
 357         (*auth_method)->auth = check_smbserver_security;
 358         (*auth_method)->get_chal = auth_get_challenge_server;
 359         (*auth_method)->send_keepalive = send_server_keepalive;
 360         (*auth_method)->free_private_data = free_server_private_data;
 361         return True;
 362 }