source3/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
  27 /****************************************************************************
  28  Support for server level security.
  29 ****************************************************************************/
  30
  31 static struct cli_state *server_cryptkey(void)
  32 {
  33         struct cli_state *cli = NULL;
  34         fstring desthost;
  35         struct in_addr dest_ip;
  36         char *p, *pserver;
  37         BOOL connected_ok = False;
  38
  39         if (!(cli = cli_initialise(cli)))
  40                 return NULL;
  41
  42         /* security = server just can't function with spnego */
  43         cli->use_spnego = False;
  44
  45         pserver = strdup(lp_passwordserver());
  46         p = pserver;
  47
  48         while(next_token( &p, desthost, LIST_SEP, sizeof(desthost))) {
  49                 standard_sub_basic(desthost);
  50                 strupper(desthost);
  51
  52                 if(!resolve_name( desthost, &dest_ip, 0x20)) {
  53                         DEBUG(1,("server_cryptkey: Can't resolve address for %s\n",desthost));
  54                         continue;
  55                 }
  56
  57                 if (ismyip(dest_ip)) {
  58                         DEBUG(1,("Password server loop - disabling password server %s\n",desthost));
  59                         continue;
  60                 }
  61
  62                 if (cli_connect(cli, desthost, &dest_ip)) {
  63                         DEBUG(3,("connected to password server %s\n",desthost));
  64                         connected_ok = True;
  65                         break;
  66                 }
  67         }
  68
  69         SAFE_FREE(pserver);
  70
  71         if (!connected_ok) {
  72                 DEBUG(0,("password server not available\n"));
  73                 cli_shutdown(cli);
  74                 return NULL;
  75         }
  76
  77         if (!attempt_netbios_session_request(cli, global_myname, desthost, &dest_ip))
  78                 return NULL;
  79
  80         if (strequal(desthost,myhostname())) {
  81                 exit_server("Password server loop!");
  82         }
  83
  84         DEBUG(3,("got session\n"));
  85
  86         if (!cli_negprot(cli)) {
  87                 DEBUG(1,("%s rejected the negprot\n",desthost));
  88                 cli_shutdown(cli);
  89                 return NULL;
  90         }
  91
  92         if (cli->protocol < PROTOCOL_LANMAN2 ||
  93             !(cli->sec_mode & 1)) {
  94                 DEBUG(1,("%s isn't in user level security mode\n",desthost));
  95                 cli_shutdown(cli);
  96                 return NULL;
  97         }
  98
  99         DEBUG(3,("password server OK\n"));
 100
 101         return cli;
 102 }
 103
 104 /****************************************************************************
 105  Clean up our allocated cli.
 106 ****************************************************************************/
 107
 108 static void free_server_private_data(void **private_data_pointer)
 109 {
 110         struct cli_state **cli = (struct cli_state **)private_data_pointer;
 111         if (*cli && (*cli)->initialised) {
 112                 cli_shutdown(*cli);
 113         }
 114 }
 115
 116 /****************************************************************************
 117  Send a 'keepalive' packet down the cli pipe.
 118 ****************************************************************************/
 119
 120 static void send_server_keepalive(void **private_data_pointer)
 121 {
 122         struct cli_state **cli = (struct cli_state **)private_data_pointer;
 123
 124         /* also send a keepalive to the password server if its still
 125            connected */
 126         if (cli && *cli && (*cli)->initialised) {
 127                 if (!send_keepalive((*cli)->fd)) {
 128                         DEBUG( 2, ( "password server keepalive failed.\n"));
 129                         cli_shutdown(*cli);
 130                 }
 131         }
 132 }
 133
 134 /****************************************************************************
 135  Get the challenge out of a password server.
 136 ****************************************************************************/
 137
 138 static DATA_BLOB auth_get_challenge_server(void **my_private_data, const struct authsupplied_info *auth_info)
 139 {
 140         struct cli_state *cli = server_cryptkey();
 141
 142         if (cli) {
 143                 DEBUG(3,("using password server validation\n"));
 144                 if ((cli->sec_mode & 2) == 0) {
 145                         /* We can't work with unencrypted password servers
 146                            unless 'encrypt passwords = no' */
 147                         DEBUG(5,("make_auth_info_server: Server is unencrypted, no challenge available..\n"));
 148
 149                         *my_private_data = (void *)cli;
 150                         return data_blob(NULL, 0);
 151
 152                 } else if (cli->secblob.length < 8) {
 153                         /* We can't do much if we don't get a full challenge */
 154                         DEBUG(2,("make_auth_info_server: Didn't receive a full challenge from server\n"));
 155                         cli_shutdown(cli);
 156                         return data_blob(NULL, 0);
 157                 }
 158
 159                 *my_private_data = (void *)cli;
 160
 161                 return data_blob(cli->secblob.data,8);
 162         } else {
 163                 return data_blob(NULL, 0);
 164         }
 165 }
 166
 167
 168 /****************************************************************************
 169  Check for a valid username and password in security=server mode.
 170   - Validate a password with the password server.
 171 ****************************************************************************/
 172
 173 static NTSTATUS check_smbserver_security(void *my_private_data,
 174                                   const auth_usersupplied_info *user_info,
 175                                   const auth_authsupplied_info *auth_info,
 176                                   auth_serversupplied_info **server_info)
 177 {
 178         struct cli_state *cli;
 179         static unsigned char badpass[24];
 180         static fstring baduser;
 181         static BOOL tested_password_server = False;
 182         static BOOL bad_password_server = False;
 183         NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;
 184         BOOL locally_made_cli = False;
 185
 186         /*
 187          * Check that the requested domain is not our own machine name.
 188          * If it is, we should never check the PDC here, we use our own local
 189          * password file.
 190          */
 191
 192         if(is_netbios_alias_or_name(user_info->domain.str)) {
 193                 DEBUG(3,("check_smbserver_security: Requested domain was for this machine.\n"));
 194                 return NT_STATUS_LOGON_FAILURE;
 195         }
 196
 197         cli = my_private_data;
 198
 199         if (cli) {
 200         } else {
 201                 cli = server_cryptkey();
 202                 locally_made_cli = True;
 203         }
 204
 205         if (!cli || !cli->initialised) {
 206                 DEBUG(1,("password server %s is not connected\n", cli->desthost));
 207                 return NT_STATUS_LOGON_FAILURE;
 208         }
 209
 210         if ((cli->sec_mode & 2) == 0) {
 211                 if (user_info->encrypted) {
 212                         DEBUG(1,("password server %s is plaintext, but we are encrypted. This just can't work :-(\n", cli->desthost));
 213                         return NT_STATUS_LOGON_FAILURE;
 214                 }
 215         } else {
 216                 if (memcmp(cli->secblob.data, auth_info->challenge.data, 8) != 0) {
 217                         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));
 218                         return NT_STATUS_LOGON_FAILURE;
 219                 }
 220         }
 221
 222         if(badpass[0] == 0)
 223                 memset(badpass, 0x1f, sizeof(badpass));
 224
 225         if((user_info->nt_resp.length == sizeof(badpass)) &&
 226            !memcmp(badpass, user_info->nt_resp.data, sizeof(badpass))) {
 227                 /*
 228                  * Very unlikely, our random bad password is the same as the users
 229                  * password.
 230                  */
 231                 memset(badpass, badpass[0]+1, sizeof(badpass));
 232         }
 233
 234         if(baduser[0] == 0) {
 235                 fstrcpy(baduser, INVALID_USER_PREFIX);
 236                 fstrcat(baduser, global_myname);
 237         }
 238
 239         /*
 240          * Attempt a session setup with a totally incorrect password.
 241          * If this succeeds with the guest bit *NOT* set then the password
 242          * server is broken and is not correctly setting the guest bit. We
 243          * need to detect this as some versions of NT4.x are broken. JRA.
 244          */
 245
 246         /* I sure as hell hope that there arn't servers out there that take
 247          * NTLMv2 and have this bug, as we don't test for that...
 248          *  - abartlet@samba.org
 249          */
 250
 251         if ((!tested_password_server) && (lp_paranoid_server_security())) {
 252                 if (cli_session_setup(cli, baduser, (char *)badpass, sizeof(badpass),
 253                                         (char *)badpass, sizeof(badpass), user_info->domain.str)) {
 254
 255                         /*
 256                          * We connected to the password server so we
 257                          * can say we've tested it.
 258                          */
 259                         tested_password_server = True;
 260
 261                         if ((SVAL(cli->inbuf,smb_vwv2) & 1) == 0) {
 262                                 DEBUG(0,("server_validate: password server %s allows users as non-guest \
 263 with a bad password.\n", cli->desthost));
 264                                 DEBUG(0,("server_validate: This is broken (and insecure) behaviour. Please do not \
 265 use this machine as the password server.\n"));
 266                                 cli_ulogoff(cli);
 267
 268                                 /*
 269                                  * Password server has the bug.
 270                                  */
 271                                 bad_password_server = True;
 272                                 return NT_STATUS_LOGON_FAILURE;
 273                         }
 274                         cli_ulogoff(cli);
 275                 }
 276         } else {
 277
 278                 /*
 279                  * We have already tested the password server.
 280                  * Fail immediately if it has the bug.
 281                  */
 282
 283                 if(bad_password_server) {
 284                         DEBUG(0,("server_validate: [1] password server %s allows users as non-guest \
 285 with a bad password.\n", cli->desthost));
 286                         DEBUG(0,("server_validate: [1] This is broken (and insecure) behaviour. Please do not \
 287 use this machine as the password server.\n"));
 288                         return NT_STATUS_LOGON_FAILURE;
 289                 }
 290         }
 291
 292         /*
 293          * Now we know the password server will correctly set the guest bit, or is
 294          * not guest enabled, we can try with the real password.
 295          */
 296
 297         if (!user_info->encrypted) {
 298                 /* Plaintext available */
 299                 if (!cli_session_setup(cli, user_info->smb_name.str,
 300                                        (char *)user_info->plaintext_password.data,
 301                                        user_info->plaintext_password.length,
 302                                        NULL, 0,
 303                                        user_info->domain.str)) {
 304                         DEBUG(1,("password server %s rejected the password\n", cli->desthost));
 305                         /* Make this cli_nt_error() when the conversion is in */
 306                         nt_status = cli_nt_error(cli);
 307                 } else {
 308                         nt_status = NT_STATUS_OK;
 309                 }
 310         } else {
 311                 if (!cli_session_setup(cli, user_info->smb_name.str,
 312                                        (char *)user_info->lm_resp.data,
 313                                        user_info->lm_resp.length,
 314                                        (char *)user_info->nt_resp.data,
 315                                        user_info->nt_resp.length,
 316                                        user_info->domain.str)) {
 317                         DEBUG(1,("password server %s rejected the password\n", cli->desthost));
 318                         /* Make this cli_nt_error() when the conversion is in */
 319                         nt_status = cli_nt_error(cli);
 320                 } else {
 321                         nt_status = NT_STATUS_OK;
 322                 }
 323         }
 324
 325         /* if logged in as guest then reject */
 326         if ((SVAL(cli->inbuf,smb_vwv2) & 1) != 0) {
 327                 DEBUG(1,("password server %s gave us guest only\n", cli->desthost));
 328                 nt_status = NT_STATUS_LOGON_FAILURE;
 329         }
 330
 331         cli_ulogoff(cli);
 332
 333         if NT_STATUS_IS_OK(nt_status) {
 334                 struct passwd *pass = Get_Pwnam(user_info->internal_username.str);
 335                 if (pass) {
 336                         if (!make_server_info_pw(server_info, pass)) {
 337                                 nt_status = NT_STATUS_NO_MEMORY;
 338                         }
 339                 } else {
 340                         nt_status = NT_STATUS_NO_SUCH_USER;
 341                 }
 342         }
 343
 344         if (locally_made_cli) {
 345                 cli_shutdown(cli);
 346         }
 347
 348         return(nt_status);
 349 }
 350
 351 BOOL auth_init_smbserver(auth_methods **auth_method)
 352 {
 353         if (!make_auth_methods(auth_method)) {
 354                 return False;
 355         }
 356         (*auth_method)->auth = check_smbserver_security;
 357         (*auth_method)->get_chal = auth_get_challenge_server;
 358         (*auth_method)->send_keepalive = send_server_keepalive;
 359         (*auth_method)->free_private_data = free_server_private_data;
 360         return True;
 361 }