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 = { sshpam_thread_conv, ctxt };
 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         buffer_init(&buffer);
 211         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 212             (const void *)&sshpam_conv);
 213         if (sshpam_err != PAM_SUCCESS)
 214                 goto auth_fail;
 215         sshpam_err = pam_authenticate(sshpam_handle, 0);
 216         if (sshpam_err != PAM_SUCCESS)
 217                 goto auth_fail;
 218         buffer_put_cstring(&buffer, "OK");
 219         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 220         buffer_free(&buffer);
 221         pthread_exit(NULL);
 222
 223  auth_fail:
 224         buffer_put_cstring(&buffer,
 225             pam_strerror(sshpam_handle, sshpam_err));
 226         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 227         buffer_free(&buffer);
 228         pthread_exit(NULL);
 229
 230         return (NULL); /* Avoid warning for non-pthread case */
 231 }
 232
 233 static void
 234 sshpam_thread_cleanup(void *ctxtp)
 235 {
 236         struct pam_ctxt *ctxt = ctxtp;
 237
 238         pthread_cancel(ctxt->pam_thread);
 239         pthread_join(ctxt->pam_thread, NULL);
 240         close(ctxt->pam_psock);
 241         close(ctxt->pam_csock);
 242 }
 243
 244 static int
 245 sshpam_null_conv(int n, const struct pam_message **msg,
 246     struct pam_response **resp, void *data)
 247 {
 248         return (PAM_CONV_ERR);
 249 }
 250
 251 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 252
 253 static void
 254 sshpam_cleanup(void *arg)
 255 {
 256         (void)arg;
 257         debug("PAM: cleanup");
 258         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 259         if (sshpam_cred_established) {
 260                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 261                 sshpam_cred_established = 0;
 262         }
 263         if (sshpam_session_open) {
 264                 pam_close_session(sshpam_handle, PAM_SILENT);
 265                 sshpam_session_open = 0;
 266         }
 267         sshpam_authenticated = sshpam_new_authtok_reqd = 0;
 268         pam_end(sshpam_handle, sshpam_err);
 269         sshpam_handle = NULL;
 270 }
 271
 272 static int
 273 sshpam_init(const char *user)
 274 {
 275         extern u_int utmp_len;
 276         const char *pam_rhost, *pam_user;
 277
 278         if (sshpam_handle != NULL) {
 279                 /* We already have a PAM context; check if the user matches */
 280                 sshpam_err = pam_get_item(sshpam_handle,
 281                     PAM_USER, (const void **)&pam_user);
 282                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 283                         return (0);
 284                 fatal_remove_cleanup(sshpam_cleanup, NULL);
 285                 pam_end(sshpam_handle, sshpam_err);
 286                 sshpam_handle = NULL;
 287         }
 288         debug("PAM: initializing for \"%s\"", user);
 289         sshpam_err = pam_start("sshd", user, &null_conv, &sshpam_handle);
 290         if (sshpam_err != PAM_SUCCESS) {
 291                 pam_end(sshpam_handle, sshpam_err);
 292                 sshpam_handle = NULL;
 293                 return (-1);
 294         }
 295         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 296         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 297         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 298         if (sshpam_err != PAM_SUCCESS) {
 299                 pam_end(sshpam_handle, sshpam_err);
 300                 sshpam_handle = NULL;
 301                 return (-1);
 302         }
 303 #ifdef PAM_TTY_KLUDGE
 304         /*
 305          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 306          * sshd doesn't set the tty until too late in the auth process and
 307          * may not even set one (for tty-less connections)
 308          */
 309         debug("PAM: setting PAM_TTY to \"ssh\"");
 310         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 311         if (sshpam_err != PAM_SUCCESS) {
 312                 pam_end(sshpam_handle, sshpam_err);
 313                 sshpam_handle = NULL;
 314                 return (-1);
 315         }
 316 #endif
 317         fatal_add_cleanup(sshpam_cleanup, NULL);
 318         return (0);
 319 }
 320
 321 static void *
 322 sshpam_init_ctx(Authctxt *authctxt)
 323 {
 324         struct pam_ctxt *ctxt;
 325         int socks[2];
 326
 327         /* Refuse to start if we don't have PAM enabled */
 328         if (!options.use_pam)
 329                 return NULL;
 330
 331         /* Initialize PAM */
 332         if (sshpam_init(authctxt->user) == -1) {
 333                 error("PAM: initialization failed");
 334                 return (NULL);
 335         }
 336
 337         ctxt = xmalloc(sizeof *ctxt);
 338         ctxt->pam_done = 0;
 339
 340         /* Start the authentication thread */
 341         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 342                 error("PAM: failed create sockets: %s", strerror(errno));
 343                 xfree(ctxt);
 344                 return (NULL);
 345         }
 346         ctxt->pam_psock = socks[0];
 347         ctxt->pam_csock = socks[1];
 348         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 349                 error("PAM: failed to start authentication thread: %s",
 350                     strerror(errno));
 351                 close(socks[0]);
 352                 close(socks[1]);
 353                 xfree(ctxt);
 354                 return (NULL);
 355         }
 356         fatal_add_cleanup(sshpam_thread_cleanup, ctxt);
 357         return (ctxt);
 358 }
 359
 360 static int
 361 sshpam_query(void *ctx, char **name, char **info,
 362     u_int *num, char ***prompts, u_int **echo_on)
 363 {
 364         Buffer buffer;
 365         struct pam_ctxt *ctxt = ctx;
 366         size_t plen;
 367         u_char type;
 368         char *msg;
 369         size_t len;
 370
 371         buffer_init(&buffer);
 372         *name = xstrdup("");
 373         *info = xstrdup("");
 374         *prompts = xmalloc(sizeof(char *));
 375         **prompts = NULL;
 376         plen = 0;
 377         *echo_on = xmalloc(sizeof(u_int));
 378         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 379                 type = buffer_get_char(&buffer);
 380                 msg = buffer_get_string(&buffer, NULL);
 381                 switch (type) {
 382                 case PAM_PROMPT_ECHO_ON:
 383                 case PAM_PROMPT_ECHO_OFF:
 384                         *num = 1;
 385                         len = plen + strlen(msg) + 1;
 386                         **prompts = xrealloc(**prompts, len);
 387                         plen += snprintf(**prompts + plen, len, "%s", msg);
 388                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 389                         xfree(msg);
 390                         return (0);
 391                 case PAM_ERROR_MSG:
 392                 case PAM_TEXT_INFO:
 393                         /* accumulate messages */
 394                         len = plen + strlen(msg) + 1;
 395                         **prompts = xrealloc(**prompts, len);
 396                         plen += snprintf(**prompts + plen, len, "%s", msg);
 397                         xfree(msg);
 398                         break;
 399                 case PAM_SUCCESS:
 400                 case PAM_AUTH_ERR:
 401                         if (**prompts != NULL) {
 402                                 /* drain any accumulated messages */
 403 #if 0 /* XXX - not compatible with privsep */
 404                                 packet_start(SSH2_MSG_USERAUTH_BANNER);
 405                                 packet_put_cstring(**prompts);
 406                                 packet_put_cstring("");
 407                                 packet_send();
 408                                 packet_write_wait();
 409 #endif
 410                                 xfree(**prompts);
 411                                 **prompts = NULL;
 412                         }
 413                         if (type == PAM_SUCCESS) {
 414                                 *num = 0;
 415                                 **echo_on = 0;
 416                                 ctxt->pam_done = 1;
 417                                 xfree(msg);
 418                                 return (0);
 419                         }
 420                         error("PAM: %s", msg);
 421                 default:
 422                         *num = 0;
 423                         **echo_on = 0;
 424                         xfree(msg);
 425                         ctxt->pam_done = -1;
 426                         return (-1);
 427                 }
 428         }
 429         return (-1);
 430 }
 431
 432 /* XXX - see also comment in auth-chall.c:verify_response */
 433 static int
 434 sshpam_respond(void *ctx, u_int num, char **resp)
 435 {
 436         Buffer buffer;
 437         struct pam_ctxt *ctxt = ctx;
 438
 439         debug2("PAM: %s", __func__);
 440         switch (ctxt->pam_done) {
 441         case 1:
 442                 sshpam_authenticated = 1;
 443                 return (0);
 444         case 0:
 445                 break;
 446         default:
 447                 return (-1);
 448         }
 449         if (num != 1) {
 450                 error("PAM: expected one response, got %u", num);
 451                 return (-1);
 452         }
 453         buffer_init(&buffer);
 454         buffer_put_cstring(&buffer, *resp);
 455         ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer);
 456         buffer_free(&buffer);
 457         return (1);
 458 }
 459
 460 static void
 461 sshpam_free_ctx(void *ctxtp)
 462 {
 463         struct pam_ctxt *ctxt = ctxtp;
 464
 465         fatal_remove_cleanup(sshpam_thread_cleanup, ctxt);
 466         sshpam_thread_cleanup(ctxtp);
 467         xfree(ctxt);
 468         /*
 469          * We don't call sshpam_cleanup() here because we may need the PAM
 470          * handle at a later stage, e.g. when setting up a session.  It's
 471          * still on the cleanup list, so pam_end() *will* be called before
 472          * the server process terminates.
 473          */
 474 }
 475
 476 KbdintDevice sshpam_device = {
 477         "pam",
 478         sshpam_init_ctx,
 479         sshpam_query,
 480         sshpam_respond,
 481         sshpam_free_ctx
 482 };
 483
 484 KbdintDevice mm_sshpam_device = {
 485         "pam",
 486         mm_sshpam_init_ctx,
 487         mm_sshpam_query,
 488         mm_sshpam_respond,
 489         mm_sshpam_free_ctx
 490 };
 491
 492 /*
 493  * This replaces auth-pam.c
 494  */
 495 void
 496 start_pam(const char *user)
 497 {
 498         if (!options.use_pam)
 499                 fatal("PAM: initialisation requested when UsePAM=no");
 500
 501         if (sshpam_init(user) == -1)
 502                 fatal("PAM: initialisation failed");
 503 }
 504
 505 void
 506 finish_pam(void)
 507 {
 508         fatal_remove_cleanup(sshpam_cleanup, NULL);
 509         sshpam_cleanup(NULL);
 510 }
 511
 512 u_int
 513 do_pam_account(void)
 514 {
 515         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 516         debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);
 517
 518         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
 519                 return (0);
 520
 521         if (sshpam_err == PAM_NEW_AUTHTOK_REQD) {
 522                 sshpam_new_authtok_reqd = 1;
 523
 524                 /* Prevent forwardings until password changed */
 525                 no_port_forwarding_flag |= 2;
 526                 no_agent_forwarding_flag |= 2;
 527                 no_x11_forwarding_flag |= 2;
 528         }
 529
 530         return (1);
 531 }
 532
 533 void
 534 do_pam_session(const char *user, const char *tty)
 535 {
 536         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 537             (const void *)&null_conv);
 538         if (sshpam_err != PAM_SUCCESS)
 539                 fatal("PAM: failed to set PAM_CONV: %s",
 540                     pam_strerror(sshpam_handle, sshpam_err));
 541         if (tty != NULL) {
 542                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 543                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 544                 if (sshpam_err != PAM_SUCCESS)
 545                         fatal("PAM: failed to set PAM_TTY: %s",
 546                             pam_strerror(sshpam_handle, sshpam_err));
 547         }
 548         sshpam_err = pam_open_session(sshpam_handle, 0);
 549         if (sshpam_err != PAM_SUCCESS)
 550                 fatal("PAM: pam_open_session(): %s",
 551                     pam_strerror(sshpam_handle, sshpam_err));
 552         sshpam_session_open = 1;
 553 }
 554
 555 void
 556 do_pam_setcred(int init)
 557 {
 558         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 559             (const void *)&null_conv);
 560         if (sshpam_err != PAM_SUCCESS)
 561                 fatal("PAM: failed to set PAM_CONV: %s",
 562                     pam_strerror(sshpam_handle, sshpam_err));
 563         if (init) {
 564                 debug("PAM: establishing credentials");
 565                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 566         } else {
 567                 debug("PAM: reinitializing credentials");
 568                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 569         }
 570         if (sshpam_err == PAM_SUCCESS) {
 571                 sshpam_cred_established = 1;
 572                 return;
 573         }
 574         if (sshpam_authenticated)
 575                 fatal("PAM: pam_setcred(): %s",
 576                     pam_strerror(sshpam_handle, sshpam_err));
 577         else
 578                 debug("PAM: pam_setcred(): %s",
 579                     pam_strerror(sshpam_handle, sshpam_err));
 580 }
 581
 582 int
 583 is_pam_password_change_required(void)
 584 {
 585         return (sshpam_new_authtok_reqd);
 586 }
 587
 588 static int
 589 pam_chauthtok_conv(int n, const struct pam_message **msg,
 590     struct pam_response **resp, void *data)
 591 {
 592         char input[PAM_MAX_MSG_SIZE];
 593         int i;
 594
 595         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 596                 return (PAM_CONV_ERR);
 597         *resp = xmalloc(n * sizeof **resp);
 598         for (i = 0; i < n; ++i) {
 599                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 600                 case PAM_PROMPT_ECHO_OFF:
 601                         resp[i]->resp =
 602                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 603                             RP_ALLOW_STDIN);
 604                         resp[i]->resp_retcode = PAM_SUCCESS;
 605                         break;
 606                 case PAM_PROMPT_ECHO_ON:
 607                         fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
 608                         fgets(input, sizeof input, stdin);
 609                         resp[i]->resp = xstrdup(input);
 610                         resp[i]->resp_retcode = PAM_SUCCESS;
 611                         break;
 612                 case PAM_ERROR_MSG:
 613                 case PAM_TEXT_INFO:
 614                         fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
 615                         resp[i]->resp_retcode = PAM_SUCCESS;
 616                         break;
 617                 default:
 618                         goto fail;
 619                 }
 620         }
 621         return (PAM_SUCCESS);
 622  fail:
 623         while (i)
 624                 xfree(resp[--i]);
 625         xfree(*resp);
 626         *resp = NULL;
 627         return (PAM_CONV_ERR);
 628 }
 629
 630 /*
 631  * XXX this should be done in the authentication phase, but ssh1 doesn't
 632  * support that
 633  */
 634 void
 635 do_pam_chauthtok(void)
 636 {
 637         struct pam_conv pam_conv = { pam_chauthtok_conv, NULL };
 638
 639         if (use_privsep)
 640                 fatal("Password expired (unable to change with privsep)");
 641         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 642             (const void *)&pam_conv);
 643         if (sshpam_err != PAM_SUCCESS)
 644                 fatal("PAM: failed to set PAM_CONV: %s",
 645                     pam_strerror(sshpam_handle, sshpam_err));
 646         debug("PAM: changing password");
 647         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 648         if (sshpam_err != PAM_SUCCESS)
 649                 fatal("PAM: pam_chauthtok(): %s",
 650                     pam_strerror(sshpam_handle, sshpam_err));
 651 }
 652
 653 void
 654 print_pam_messages(void)
 655 {
 656         /* XXX */
 657 }
 658
 659 char **
 660 fetch_pam_environment(void)
 661 {
 662 #ifdef HAVE_PAM_GETENVLIST
 663         debug("PAM: retrieving environment");
 664         return (pam_getenvlist(sshpam_handle));
 665 #else
 666         return (NULL);
 667 #endif
 668 }
 669
 670 void
 671 free_pam_environment(char **env)
 672 {
 673         char **envp;
 674
 675         if (env == NULL)
 676                 return;
 677
 678         for (envp = env; *envp; envp++)
 679                 xfree(*envp);
 680         xfree(env);
 681 }
 682
 683 #endif /* USE_PAM */