auth-pam.c

   1 /*-
   2  * Copyright (c) 2002 Networks Associates Technology, Inc.
   3  * All rights reserved.
   4  *
   5  * This software was developed for the FreeBSD Project by ThinkSec AS and
   6  * NAI Labs, the Security Research Division of Network Associates, Inc.
   7  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
   8  * DARPA CHATS research program.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 /* Based on $FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des Exp $ */
  33 #include "includes.h"
  34 RCSID("$Id$");
  35
  36 #ifdef USE_PAM
  37 #include <security/pam_appl.h>
  38
  39 #include "auth.h"
  40 #include "auth-pam.h"
  41 #include "buffer.h"
  42 #include "bufaux.h"
  43 #include "canohost.h"
  44 #include "log.h"
  45 #include "monitor_wrap.h"
  46 #include "msg.h"
  47 #include "packet.h"
  48 #include "readpass.h"
  49 #include "servconf.h"
  50 #include "ssh2.h"
  51 #include "xmalloc.h"
  52 #include "auth-options.h"
  53
  54 extern ServerOptions options;
  55
  56 #define __unused
  57
  58 #ifdef USE_POSIX_THREADS
  59 #include <pthread.h>
  60 /*
  61  * Avoid namespace clash when *not* using pthreads for systems *with*
  62  * pthreads, which unconditionally define pthread_t via sys/types.h
  63  * (e.g. Linux)
  64  */
  65 typedef pthread_t sp_pthread_t;
  66 #else
  67 /*
  68  * Simulate threads with processes.
  69  */
  70 typedef pid_t sp_pthread_t;
  71
  72 static void
  73 pthread_exit(void *value __unused)
  74 {
  75         _exit(0);
  76 }
  77
  78 static int
  79 pthread_create(sp_pthread_t *thread, const void *attr __unused,
  80     void *(*thread_start)(void *), void *arg)
  81 {
  82         pid_t pid;
  83
  84         switch ((pid = fork())) {
  85         case -1:
  86                 error("fork(): %s", strerror(errno));
  87                 return (-1);
  88         case 0:
  89                 thread_start(arg);
  90                 _exit(1);
  91         default:
  92                 *thread = pid;
  93                 return (0);
  94         }
  95 }
  96
  97 static int
  98 pthread_cancel(sp_pthread_t thread)
  99 {
 100         return (kill(thread, SIGTERM));
 101 }
 102
 103 static int
 104 pthread_join(sp_pthread_t thread, void **value __unused)
 105 {
 106         int status;
 107
 108         waitpid(thread, &status, 0);
 109         return (status);
 110 }
 111 #endif
 112
 113
 114 static pam_handle_t *sshpam_handle;
 115 static int sshpam_err;
 116 static int sshpam_authenticated;
 117 static int sshpam_new_authtok_reqd;
 118 static int sshpam_session_open;
 119 static int sshpam_cred_established;
 120
 121 struct pam_ctxt {
 122         sp_pthread_t     pam_thread;
 123         int              pam_psock;
 124         int              pam_csock;
 125         int              pam_done;
 126 };
 127
 128 static void sshpam_free_ctx(void *);
 129
 130 /*
 131  * Conversation function for authentication thread.
 132  */
 133 static int
 134 sshpam_thread_conv(int n, const struct pam_message **msg,
 135     struct pam_response **resp, void *data)
 136 {
 137         Buffer buffer;
 138         struct pam_ctxt *ctxt;
 139         int i;
 140
 141         ctxt = data;
 142         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 143                 return (PAM_CONV_ERR);
 144         *resp = xmalloc(n * sizeof **resp);
 145         buffer_init(&buffer);
 146         for (i = 0; i < n; ++i) {
 147                 resp[i]->resp_retcode = 0;
 148                 resp[i]->resp = NULL;
 149                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 150                 case PAM_PROMPT_ECHO_OFF:
 151                         buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
 152                         ssh_msg_send(ctxt->pam_csock,
 153                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 154                         ssh_msg_recv(ctxt->pam_csock, &buffer);
 155                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 156                                 goto fail;
 157                         resp[i]->resp = buffer_get_string(&buffer, NULL);
 158                         break;
 159                 case PAM_PROMPT_ECHO_ON:
 160                         buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
 161                         ssh_msg_send(ctxt->pam_csock,
 162                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 163                         ssh_msg_recv(ctxt->pam_csock, &buffer);
 164                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 165                                 goto fail;
 166                         resp[i]->resp = buffer_get_string(&buffer, NULL);
 167                         break;
 168                 case PAM_ERROR_MSG:
 169                         buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
 170                         ssh_msg_send(ctxt->pam_csock,
 171                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 172                         break;
 173                 case PAM_TEXT_INFO:
 174                         buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
 175                         ssh_msg_send(ctxt->pam_csock,
 176                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 177                         break;
 178                 default:
 179                         goto fail;
 180                 }
 181                 buffer_clear(&buffer);
 182         }
 183         buffer_free(&buffer);
 184         return (PAM_SUCCESS);
 185  fail:
 186         while (i)
 187                 xfree(resp[--i]);
 188         xfree(*resp);
 189         *resp = NULL;
 190         buffer_free(&buffer);
 191         return (PAM_CONV_ERR);
 192 }
 193
 194 /*
 195  * Authentication thread.
 196  */
 197 static void *
 198 sshpam_thread(void *ctxtp)
 199 {
 200         struct pam_ctxt *ctxt = ctxtp;
 201         Buffer buffer;
 202         struct pam_conv sshpam_conv;
 203 #ifndef USE_POSIX_THREADS
 204         const char *pam_user;
 205
 206         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 207         setproctitle("%s [pam]", pam_user);
 208 #endif
 209
 210         sshpam_conv.conv = sshpam_thread_conv;
 211         sshpam_conv.appdata_ptr = ctxt;
 212
 213         buffer_init(&buffer);
 214         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 215             (const void *)&sshpam_conv);
 216         if (sshpam_err != PAM_SUCCESS)
 217                 goto auth_fail;
 218         sshpam_err = pam_authenticate(sshpam_handle, 0);
 219         if (sshpam_err != PAM_SUCCESS)
 220                 goto auth_fail;
 221         buffer_put_cstring(&buffer, "OK");
 222         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 223         buffer_free(&buffer);
 224         pthread_exit(NULL);
 225
 226  auth_fail:
 227         buffer_put_cstring(&buffer,
 228             pam_strerror(sshpam_handle, sshpam_err));
 229         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 230         buffer_free(&buffer);
 231         pthread_exit(NULL);
 232
 233         return (NULL); /* Avoid warning for non-pthread case */
 234 }
 235
 236 static void
 237 sshpam_thread_cleanup(void *ctxtp)
 238 {
 239         struct pam_ctxt *ctxt = ctxtp;
 240
 241         pthread_cancel(ctxt->pam_thread);
 242         pthread_join(ctxt->pam_thread, NULL);
 243         close(ctxt->pam_psock);
 244         close(ctxt->pam_csock);
 245 }
 246
 247 static int
 248 sshpam_null_conv(int n, const struct pam_message **msg,
 249     struct pam_response **resp, void *data)
 250 {
 251         return (PAM_CONV_ERR);
 252 }
 253
 254 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 255
 256 static void
 257 sshpam_cleanup(void *arg)
 258 {
 259         (void)arg;
 260         debug("PAM: cleanup");
 261         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 262         if (sshpam_cred_established) {
 263                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 264                 sshpam_cred_established = 0;
 265         }
 266         if (sshpam_session_open) {
 267                 pam_close_session(sshpam_handle, PAM_SILENT);
 268                 sshpam_session_open = 0;
 269         }
 270         sshpam_authenticated = sshpam_new_authtok_reqd = 0;
 271         pam_end(sshpam_handle, sshpam_err);
 272         sshpam_handle = NULL;
 273 }
 274
 275 static int
 276 sshpam_init(const char *user)
 277 {
 278         extern u_int utmp_len;
 279         const char *pam_rhost, *pam_user;
 280
 281         if (sshpam_handle != NULL) {
 282                 /* We already have a PAM context; check if the user matches */
 283                 sshpam_err = pam_get_item(sshpam_handle,
 284                     PAM_USER, (const void **)&pam_user);
 285                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 286                         return (0);
 287                 fatal_remove_cleanup(sshpam_cleanup, NULL);
 288                 pam_end(sshpam_handle, sshpam_err);
 289                 sshpam_handle = NULL;
 290         }
 291         debug("PAM: initializing for \"%s\"", user);
 292         sshpam_err = pam_start("sshd", user, &null_conv, &sshpam_handle);
 293         if (sshpam_err != PAM_SUCCESS) {
 294                 pam_end(sshpam_handle, sshpam_err);
 295                 sshpam_handle = NULL;
 296                 return (-1);
 297         }
 298         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 299         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 300         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 301         if (sshpam_err != PAM_SUCCESS) {
 302                 pam_end(sshpam_handle, sshpam_err);
 303                 sshpam_handle = NULL;
 304                 return (-1);
 305         }
 306 #ifdef PAM_TTY_KLUDGE
 307         /*
 308          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 309          * sshd doesn't set the tty until too late in the auth process and
 310          * may not even set one (for tty-less connections)
 311          */
 312         debug("PAM: setting PAM_TTY to \"ssh\"");
 313         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 314         if (sshpam_err != PAM_SUCCESS) {
 315                 pam_end(sshpam_handle, sshpam_err);
 316                 sshpam_handle = NULL;
 317                 return (-1);
 318         }
 319 #endif
 320         fatal_add_cleanup(sshpam_cleanup, NULL);
 321         return (0);
 322 }
 323
 324 static void *
 325 sshpam_init_ctx(Authctxt *authctxt)
 326 {
 327         struct pam_ctxt *ctxt;
 328         int socks[2];
 329
 330         /* Refuse to start if we don't have PAM enabled */
 331         if (!options.use_pam)
 332                 return NULL;
 333
 334         /* Initialize PAM */
 335         if (sshpam_init(authctxt->user) == -1) {
 336                 error("PAM: initialization failed");
 337                 return (NULL);
 338         }
 339
 340         ctxt = xmalloc(sizeof *ctxt);
 341         ctxt->pam_done = 0;
 342
 343         /* Start the authentication thread */
 344         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 345                 error("PAM: failed create sockets: %s", strerror(errno));
 346                 xfree(ctxt);
 347                 return (NULL);
 348         }
 349         ctxt->pam_psock = socks[0];
 350         ctxt->pam_csock = socks[1];
 351         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 352                 error("PAM: failed to start authentication thread: %s",
 353                     strerror(errno));
 354                 close(socks[0]);
 355                 close(socks[1]);
 356                 xfree(ctxt);
 357                 return (NULL);
 358         }
 359         fatal_add_cleanup(sshpam_thread_cleanup, ctxt);
 360         return (ctxt);
 361 }
 362
 363 static int
 364 sshpam_query(void *ctx, char **name, char **info,
 365     u_int *num, char ***prompts, u_int **echo_on)
 366 {
 367         Buffer buffer;
 368         struct pam_ctxt *ctxt = ctx;
 369         size_t plen;
 370         u_char type;
 371         char *msg;
 372         size_t len;
 373
 374         buffer_init(&buffer);
 375         *name = xstrdup("");
 376         *info = xstrdup("");
 377         *prompts = xmalloc(sizeof(char *));
 378         **prompts = NULL;
 379         plen = 0;
 380         *echo_on = xmalloc(sizeof(u_int));
 381         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 382                 type = buffer_get_char(&buffer);
 383                 msg = buffer_get_string(&buffer, NULL);
 384                 switch (type) {
 385                 case PAM_PROMPT_ECHO_ON:
 386                 case PAM_PROMPT_ECHO_OFF:
 387                         *num = 1;
 388                         len = plen + strlen(msg) + 1;
 389                         **prompts = xrealloc(**prompts, len);
 390                         plen += snprintf(**prompts + plen, len, "%s", msg);
 391                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 392                         xfree(msg);
 393                         return (0);
 394                 case PAM_ERROR_MSG:
 395                 case PAM_TEXT_INFO:
 396                         /* accumulate messages */
 397                         len = plen + strlen(msg) + 1;
 398                         **prompts = xrealloc(**prompts, len);
 399                         plen += snprintf(**prompts + plen, len, "%s", msg);
 400                         xfree(msg);
 401                         break;
 402                 case PAM_SUCCESS:
 403                 case PAM_AUTH_ERR:
 404                         if (**prompts != NULL) {
 405                                 /* drain any accumulated messages */
 406 #if 0 /* XXX - not compatible with privsep */
 407                                 packet_start(SSH2_MSG_USERAUTH_BANNER);
 408                                 packet_put_cstring(**prompts);
 409                                 packet_put_cstring("");
 410                                 packet_send();
 411                                 packet_write_wait();
 412 #endif
 413                                 xfree(**prompts);
 414                                 **prompts = NULL;
 415                         }
 416                         if (type == PAM_SUCCESS) {
 417                                 *num = 0;
 418                                 **echo_on = 0;
 419                                 ctxt->pam_done = 1;
 420                                 xfree(msg);
 421                                 return (0);
 422                         }
 423                         error("PAM: %s", msg);
 424                 default:
 425                         *num = 0;
 426                         **echo_on = 0;
 427                         xfree(msg);
 428                         ctxt->pam_done = -1;
 429                         return (-1);
 430                 }
 431         }
 432         return (-1);
 433 }
 434
 435 /* XXX - see also comment in auth-chall.c:verify_response */
 436 static int
 437 sshpam_respond(void *ctx, u_int num, char **resp)
 438 {
 439         Buffer buffer;
 440         struct pam_ctxt *ctxt = ctx;
 441
 442         debug2("PAM: %s", __func__);
 443         switch (ctxt->pam_done) {
 444         case 1:
 445                 sshpam_authenticated = 1;
 446                 return (0);
 447         case 0:
 448                 break;
 449         default:
 450                 return (-1);
 451         }
 452         if (num != 1) {
 453                 error("PAM: expected one response, got %u", num);
 454                 return (-1);
 455         }
 456         buffer_init(&buffer);
 457         buffer_put_cstring(&buffer, *resp);
 458         ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer);
 459         buffer_free(&buffer);
 460         return (1);
 461 }
 462
 463 static void
 464 sshpam_free_ctx(void *ctxtp)
 465 {
 466         struct pam_ctxt *ctxt = ctxtp;
 467
 468         fatal_remove_cleanup(sshpam_thread_cleanup, ctxt);
 469         sshpam_thread_cleanup(ctxtp);
 470         xfree(ctxt);
 471         /*
 472          * We don't call sshpam_cleanup() here because we may need the PAM
 473          * handle at a later stage, e.g. when setting up a session.  It's
 474          * still on the cleanup list, so pam_end() *will* be called before
 475          * the server process terminates.
 476          */
 477 }
 478
 479 KbdintDevice sshpam_device = {
 480         "pam",
 481         sshpam_init_ctx,
 482         sshpam_query,
 483         sshpam_respond,
 484         sshpam_free_ctx
 485 };
 486
 487 KbdintDevice mm_sshpam_device = {
 488         "pam",
 489         mm_sshpam_init_ctx,
 490         mm_sshpam_query,
 491         mm_sshpam_respond,
 492         mm_sshpam_free_ctx
 493 };
 494
 495 /*
 496  * This replaces auth-pam.c
 497  */
 498 void
 499 start_pam(const char *user)
 500 {
 501         if (!options.use_pam)
 502                 fatal("PAM: initialisation requested when UsePAM=no");
 503
 504         if (sshpam_init(user) == -1)
 505                 fatal("PAM: initialisation failed");
 506 }
 507
 508 void
 509 finish_pam(void)
 510 {
 511         fatal_remove_cleanup(sshpam_cleanup, NULL);
 512         sshpam_cleanup(NULL);
 513 }
 514
 515 u_int
 516 do_pam_account(void)
 517 {
 518         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 519         debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);
 520
 521         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
 522                 return (0);
 523
 524         if (sshpam_err == PAM_NEW_AUTHTOK_REQD) {
 525                 sshpam_new_authtok_reqd = 1;
 526
 527                 /* Prevent forwardings until password changed */
 528                 no_port_forwarding_flag |= 2;
 529                 no_agent_forwarding_flag |= 2;
 530                 no_x11_forwarding_flag |= 2;
 531         }
 532
 533         return (1);
 534 }
 535
 536 void
 537 do_pam_session(const char *user, const char *tty)
 538 {
 539         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 540             (const void *)&null_conv);
 541         if (sshpam_err != PAM_SUCCESS)
 542                 fatal("PAM: failed to set PAM_CONV: %s",
 543                     pam_strerror(sshpam_handle, sshpam_err));
 544         if (tty != NULL) {
 545                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 546                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 547                 if (sshpam_err != PAM_SUCCESS)
 548                         fatal("PAM: failed to set PAM_TTY: %s",
 549                             pam_strerror(sshpam_handle, sshpam_err));
 550         }
 551         sshpam_err = pam_open_session(sshpam_handle, 0);
 552         if (sshpam_err != PAM_SUCCESS)
 553                 fatal("PAM: pam_open_session(): %s",
 554                     pam_strerror(sshpam_handle, sshpam_err));
 555         sshpam_session_open = 1;
 556 }
 557
 558 void
 559 do_pam_setcred(int init)
 560 {
 561         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 562             (const void *)&null_conv);
 563         if (sshpam_err != PAM_SUCCESS)
 564                 fatal("PAM: failed to set PAM_CONV: %s",
 565                     pam_strerror(sshpam_handle, sshpam_err));
 566         if (init) {
 567                 debug("PAM: establishing credentials");
 568                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 569         } else {
 570                 debug("PAM: reinitializing credentials");
 571                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 572         }
 573         if (sshpam_err == PAM_SUCCESS) {
 574                 sshpam_cred_established = 1;
 575                 return;
 576         }
 577         if (sshpam_authenticated)
 578                 fatal("PAM: pam_setcred(): %s",
 579                     pam_strerror(sshpam_handle, sshpam_err));
 580         else
 581                 debug("PAM: pam_setcred(): %s",
 582                     pam_strerror(sshpam_handle, sshpam_err));
 583 }
 584
 585 int
 586 is_pam_password_change_required(void)
 587 {
 588         return (sshpam_new_authtok_reqd);
 589 }
 590
 591 static int
 592 pam_chauthtok_conv(int n, const struct pam_message **msg,
 593     struct pam_response **resp, void *data)
 594 {
 595         char input[PAM_MAX_MSG_SIZE];
 596         int i;
 597
 598         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 599                 return (PAM_CONV_ERR);
 600         *resp = xmalloc(n * sizeof **resp);
 601         for (i = 0; i < n; ++i) {
 602                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 603                 case PAM_PROMPT_ECHO_OFF:
 604                         resp[i]->resp =
 605                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 606                             RP_ALLOW_STDIN);
 607                         resp[i]->resp_retcode = PAM_SUCCESS;
 608                         break;
 609                 case PAM_PROMPT_ECHO_ON:
 610                         fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
 611                         fgets(input, sizeof input, stdin);
 612                         resp[i]->resp = xstrdup(input);
 613                         resp[i]->resp_retcode = PAM_SUCCESS;
 614                         break;
 615                 case PAM_ERROR_MSG:
 616                 case PAM_TEXT_INFO:
 617                         fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
 618                         resp[i]->resp_retcode = PAM_SUCCESS;
 619                         break;
 620                 default:
 621                         goto fail;
 622                 }
 623         }
 624         return (PAM_SUCCESS);
 625  fail:
 626         while (i)
 627                 xfree(resp[--i]);
 628         xfree(*resp);
 629         *resp = NULL;
 630         return (PAM_CONV_ERR);
 631 }
 632
 633 /*
 634  * XXX this should be done in the authentication phase, but ssh1 doesn't
 635  * support that
 636  */
 637 void
 638 do_pam_chauthtok(void)
 639 {
 640         struct pam_conv pam_conv;
 641
 642         pam_conv.conv = pam_chauthtok_conv;
 643         pam_conv.appdata_ptr = NULL;
 644
 645         if (use_privsep)
 646                 fatal("Password expired (unable to change with privsep)");
 647         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 648             (const void *)&pam_conv);
 649         if (sshpam_err != PAM_SUCCESS)
 650                 fatal("PAM: failed to set PAM_CONV: %s",
 651                     pam_strerror(sshpam_handle, sshpam_err));
 652         debug("PAM: changing password");
 653         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 654         if (sshpam_err != PAM_SUCCESS)
 655                 fatal("PAM: pam_chauthtok(): %s",
 656                     pam_strerror(sshpam_handle, sshpam_err));
 657 }
 658
 659 /*
 660  * Set a PAM environment string. We need to do this so that the session
 661  * modules can handle things like Kerberos/GSI credentials that appear
 662  * during the ssh authentication process.
 663  */
 664
 665 int
 666 do_pam_putenv(char *name, char *value)
 667 {
 668         char *compound;
 669         int ret = 1;
 670
 671 #ifdef HAVE_PAM_PUTENV
 672         compound = xmalloc(strlen(name)+strlen(value)+2);
 673         if (compound) {
 674                 sprintf(compound,"%s=%s",name,value);
 675                 ret = pam_putenv(sshpam_handle,compound);
 676                 xfree(compound);
 677         }
 678 #endif
 679         return (ret);
 680 }
 681
 682 void
 683 print_pam_messages(void)
 684 {
 685         /* XXX */
 686 }
 687
 688 char **
 689 fetch_pam_environment(void)
 690 {
 691 #ifdef HAVE_PAM_GETENVLIST
 692         debug("PAM: retrieving environment");
 693         return (pam_getenvlist(sshpam_handle));
 694 #else
 695         return (NULL);
 696 #endif
 697 }
 698
 699 void
 700 free_pam_environment(char **env)
 701 {
 702         char **envp;
 703
 704         if (env == NULL)
 705                 return;
 706
 707         for (envp = env; *envp; envp++)
 708                 xfree(*envp);
 709         xfree(env);
 710 }
 711
 712 #endif /* USE_PAM */