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                 SAFE_FREE(*cli);
 115         }
 116 }
 117
 118 /****************************************************************************
 119  Send a 'keepalive' packet down the cli pipe.
 120 ****************************************************************************/
 121
 122 static void send_server_keepalive(void **private_data_pointer)
 123 {
 124         struct cli_state **cli = (struct cli_state **)private_data_pointer;
 125
 126         /* also send a keepalive to the password server if its still
 127            connected */
 128         if (cli && *cli && (*cli)->initialised) {
 129                 if (!send_keepalive((*cli)->fd)) {
 130                         DEBUG( 2, ( "password server keepalive failed.\n"));
 131                         cli_shutdown(*cli);
 132                         SAFE_FREE(*cli);
 133                 }
 134         }
 135 }
 136
 137 /****************************************************************************
 138  Get the challange out of a password server.
 139 ****************************************************************************/
 140
 141 static DATA_BLOB auth_get_challange_server(void **my_private_data, const struct authsupplied_info *auth_info)
 142 {
 143         struct cli_state *cli = server_cryptkey();
 144
 145         if (cli) {
 146                 DEBUG(3,("using password server validation\n"));
 147                 if ((cli->sec_mode & 2) == 0) {
 148                         /* We can't work with unencrypted password servers
 149                            unless 'encrypt passwords = no' */
 150                         DEBUG(5,("make_auth_info_server: Server is unencrypted, no challange available..\n"));
 151
 152                         *my_private_data = (void *)cli;
 153                         return data_blob(NULL, 0);
 154
 155                 } else if (cli->secblob.length < 8) {
 156                         /* We can't do much if we don't get a full challange */
 157                         DEBUG(2,("make_auth_info_server: Didn't receive a full challange from server\n"));
 158                         cli_shutdown(cli);
 159                         return data_blob(NULL, 0);
 160                 }
 161
 162                 *my_private_data = (void *)cli;
 163
 164                 return data_blob(cli->secblob.data,8);
 165         } else {
 166                 return data_blob(NULL, 0);
 167         }
 168 }
 169
 170
 171 /****************************************************************************
 172  Check for a valid username and password in security=server mode.
 173   - Validate a password with the password server.
 174 ****************************************************************************/
 175
 176 static NTSTATUS check_smbserver_security(void *my_private_data,
 177                                   const auth_usersupplied_info *user_info,
 178                                   const auth_authsupplied_info *auth_info,
 179                                   auth_serversupplied_info **server_info)
 180 {
 181         struct cli_state *cli;
 182         static unsigned char badpass[24];
 183         static fstring baduser;
 184         static BOOL tested_password_server = False;
 185         static BOOL bad_password_server = False;
 186         NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;
 187         BOOL locally_made_cli = False;
 188
 189         cli = my_private_data;
 190
 191         if (cli) {
 192         } else {
 193                 cli = server_cryptkey();
 194                 locally_made_cli = True;
 195         }
 196
 197         if (!cli || !cli->initialised) {
 198                 DEBUG(1,("password server %s is not connected\n", cli->desthost));
 199                 return NT_STATUS_LOGON_FAILURE;
 200         }
 201
 202         if ((cli->sec_mode & 2) == 0) {
 203                 if (user_info->encrypted) {
 204                         DEBUG(1,("password server %s is plaintext, but we are encrypted. This just can't work :-(\n", cli->desthost));
 205                         return NT_STATUS_LOGON_FAILURE;
 206                 }
 207         } else {
 208                 if (memcmp(cli->secblob.data, auth_info->challange.data, 8) != 0) {
 209                         DEBUG(1,("the challange that the password server (%s) supplied us is not the one we gave our client. This just can't work :-(\n", cli->desthost));
 210                         return NT_STATUS_LOGON_FAILURE;
 211                 }
 212         }
 213
 214         if(badpass[0] == 0)
 215                 memset(badpass, 0x1f, sizeof(badpass));
 216
 217         if((user_info->nt_resp.length == sizeof(badpass)) &&
 218            !memcmp(badpass, user_info->nt_resp.data, sizeof(badpass))) {
 219                 /*
 220                  * Very unlikely, our random bad password is the same as the users
 221                  * password.
 222                  */
 223                 memset(badpass, badpass[0]+1, sizeof(badpass));
 224         }
 225
 226         if(baduser[0] == 0) {
 227                 fstrcpy(baduser, INVALID_USER_PREFIX);
 228                 fstrcat(baduser, global_myname);
 229         }
 230
 231         /*
 232          * Attempt a session setup with a totally incorrect password.
 233          * If this succeeds with the guest bit *NOT* set then the password
 234          * server is broken and is not correctly setting the guest bit. We
 235          * need to detect this as some versions of NT4.x are broken. JRA.
 236          */
 237
 238         /* I sure as hell hope that there arn't servers out there that take
 239          * NTLMv2 and have this bug, as we don't test for that...
 240          *  - abartlet@samba.org
 241          */
 242
 243         if ((!tested_password_server) && (lp_paranoid_server_security())) {
 244                 if (cli_session_setup(cli, baduser, (char *)badpass, sizeof(badpass),
 245                                         (char *)badpass, sizeof(badpass), user_info->domain.str)) {
 246
 247                         /*
 248                          * We connected to the password server so we
 249                          * can say we've tested it.
 250                          */
 251                         tested_password_server = True;
 252
 253                         if ((SVAL(cli->inbuf,smb_vwv2) & 1) == 0) {
 254                                 DEBUG(0,("server_validate: password server %s allows users as non-guest \
 255 with a bad password.\n", cli->desthost));
 256                                 DEBUG(0,("server_validate: This is broken (and insecure) behaviour. Please do not \
 257 use this machine as the password server.\n"));
 258                                 cli_ulogoff(cli);
 259
 260                                 /*
 261                                  * Password server has the bug.
 262                                  */
 263                                 bad_password_server = True;
 264                                 return NT_STATUS_LOGON_FAILURE;
 265                         }
 266                         cli_ulogoff(cli);
 267                 }
 268         } else {
 269
 270                 /*
 271                  * We have already tested the password server.
 272                  * Fail immediately if it has the bug.
 273                  */
 274
 275                 if(bad_password_server) {
 276                         DEBUG(0,("server_validate: [1] password server %s allows users as non-guest \
 277 with a bad password.\n", cli->desthost));
 278                         DEBUG(0,("server_validate: [1] This is broken (and insecure) behaviour. Please do not \
 279 use this machine as the password server.\n"));
 280                         return NT_STATUS_LOGON_FAILURE;
 281                 }
 282         }
 283
 284         /*
 285          * Now we know the password server will correctly set the guest bit, or is
 286          * not guest enabled, we can try with the real password.
 287          */
 288
 289         if (!user_info->encrypted) {
 290                 /* Plaintext available */
 291                 if (!cli_session_setup(cli, user_info->smb_name.str,
 292                                        (char *)user_info->plaintext_password.data,
 293                                        user_info->plaintext_password.length,
 294                                        NULL, 0,
 295                                        user_info->domain.str)) {
 296                         DEBUG(1,("password server %s rejected the password\n", cli->desthost));
 297                         /* Make this cli_nt_error() when the conversion is in */
 298                         nt_status = cli_nt_error(cli);
 299                 } else {
 300                         nt_status = NT_STATUS_OK;
 301                 }
 302         } else {
 303                 if (!cli_session_setup(cli, user_info->smb_name.str,
 304                                        (char *)user_info->lm_resp.data,
 305                                        user_info->lm_resp.length,
 306                                        (char *)user_info->nt_resp.data,
 307                                        user_info->nt_resp.length,
 308                                        user_info->domain.str)) {
 309                         DEBUG(1,("password server %s rejected the password\n", cli->desthost));
 310                         /* Make this cli_nt_error() when the conversion is in */
 311                         nt_status = cli_nt_error(cli);
 312                 } else {
 313                         nt_status = NT_STATUS_OK;
 314                 }
 315         }
 316
 317         /* if logged in as guest then reject */
 318         if ((SVAL(cli->inbuf,smb_vwv2) & 1) != 0) {
 319                 DEBUG(1,("password server %s gave us guest only\n", cli->desthost));
 320                 nt_status = NT_STATUS_LOGON_FAILURE;
 321         }
 322
 323         cli_ulogoff(cli);
 324
 325         if NT_STATUS_IS_OK(nt_status) {
 326                 struct passwd *pass = Get_Pwnam(user_info->internal_username.str);
 327                 if (pass) {
 328                         if (!make_server_info_pw(server_info, pass)) {
 329                                 nt_status = NT_STATUS_NO_MEMORY;
 330                         }
 331                 } else {
 332                         nt_status = NT_STATUS_NO_SUCH_USER;
 333                 }
 334         }
 335
 336         if (locally_made_cli) {
 337                 cli_shutdown(cli);
 338                 SAFE_FREE(cli);
 339         }
 340
 341         return(nt_status);
 342 }
 343
 344 BOOL auth_init_smbserver(auth_methods **auth_method)
 345 {
 346         if (!make_auth_methods(auth_method)) {
 347                 return False;
 348         }
 349         (*auth_method)->auth = check_smbserver_security;
 350         (*auth_method)->get_chal = auth_get_challange_server;
 351         (*auth_method)->send_keepalive = send_server_keepalive;
 352         (*auth_method)->free_private_data = free_server_private_data;
 353         return True;
 354 }