openssh/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 = NULL;
 115 static int sshpam_err = 0;
 116 static int sshpam_authenticated = 0;
 117 static int sshpam_new_authtok_reqd = 0;
 118 static int sshpam_session_open = 0;
 119 static int sshpam_cred_established = 0;
 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         struct pam_response *reply;
 140         int i;
 141
 142         *resp = NULL;
 143
 144         ctxt = data;
 145         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 146                 return (PAM_CONV_ERR);
 147
 148         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 149                 return (PAM_CONV_ERR);
 150         memset(reply, 0, n * sizeof(*reply));
 151
 152         buffer_init(&buffer);
 153         for (i = 0; i < n; ++i) {
 154                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 155                 case PAM_PROMPT_ECHO_OFF:
 156                         buffer_put_cstring(&buffer,
 157                             PAM_MSG_MEMBER(msg, i, msg));
 158                         ssh_msg_send(ctxt->pam_csock,
 159                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 160                         ssh_msg_recv(ctxt->pam_csock, &buffer);
 161                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 162                                 goto fail;
 163                         reply[i].resp = buffer_get_string(&buffer, NULL);
 164                         break;
 165                 case PAM_PROMPT_ECHO_ON:
 166                         buffer_put_cstring(&buffer,
 167                             PAM_MSG_MEMBER(msg, i, msg));
 168                         ssh_msg_send(ctxt->pam_csock,
 169                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 170                         ssh_msg_recv(ctxt->pam_csock, &buffer);
 171                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 172                                 goto fail;
 173                         reply[i].resp = buffer_get_string(&buffer, NULL);
 174                         break;
 175                 case PAM_ERROR_MSG:
 176                         buffer_put_cstring(&buffer,
 177                             PAM_MSG_MEMBER(msg, i, msg));
 178                         ssh_msg_send(ctxt->pam_csock,
 179                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 180                         break;
 181                 case PAM_TEXT_INFO:
 182                         buffer_put_cstring(&buffer,
 183                             PAM_MSG_MEMBER(msg, i, msg));
 184                         ssh_msg_send(ctxt->pam_csock,
 185                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
 186                         break;
 187                 default:
 188                         goto fail;
 189                 }
 190                 buffer_clear(&buffer);
 191         }
 192         buffer_free(&buffer);
 193         *resp = reply;
 194         return (PAM_SUCCESS);
 195
 196  fail:
 197         for(i = 0; i < n; i++) {
 198                 if (reply[i].resp != NULL)
 199                         xfree(reply[i].resp);
 200         }
 201         xfree(reply);
 202         buffer_free(&buffer);
 203         return (PAM_CONV_ERR);
 204 }
 205
 206 /*
 207  * Authentication thread.
 208  */
 209 static void *
 210 sshpam_thread(void *ctxtp)
 211 {
 212         struct pam_ctxt *ctxt = ctxtp;
 213         Buffer buffer;
 214         struct pam_conv sshpam_conv;
 215 #ifndef USE_POSIX_THREADS
 216         const char *pam_user;
 217
 218         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 219         setproctitle("%s [pam]", pam_user);
 220 #endif
 221
 222         sshpam_conv.conv = sshpam_thread_conv;
 223         sshpam_conv.appdata_ptr = ctxt;
 224
 225         buffer_init(&buffer);
 226         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 227             (const void *)&sshpam_conv);
 228         if (sshpam_err != PAM_SUCCESS)
 229                 goto auth_fail;
 230         sshpam_err = pam_authenticate(sshpam_handle, 0);
 231         if (sshpam_err != PAM_SUCCESS)
 232                 goto auth_fail;
 233         buffer_put_cstring(&buffer, "OK");
 234         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 235         buffer_free(&buffer);
 236         pthread_exit(NULL);
 237
 238  auth_fail:
 239         buffer_put_cstring(&buffer,
 240             pam_strerror(sshpam_handle, sshpam_err));
 241         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 242         buffer_free(&buffer);
 243         pthread_exit(NULL);
 244
 245         return (NULL); /* Avoid warning for non-pthread case */
 246 }
 247
 248 static void
 249 sshpam_thread_cleanup(void *ctxtp)
 250 {
 251         struct pam_ctxt *ctxt = ctxtp;
 252
 253         pthread_cancel(ctxt->pam_thread);
 254         pthread_join(ctxt->pam_thread, NULL);
 255         close(ctxt->pam_psock);
 256         close(ctxt->pam_csock);
 257 }
 258
 259 static int
 260 sshpam_null_conv(int n, const struct pam_message **msg,
 261     struct pam_response **resp, void *data)
 262 {
 263         return (PAM_CONV_ERR);
 264 }
 265
 266 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 267
 268 static void
 269 sshpam_cleanup(void *arg)
 270 {
 271         (void)arg;
 272         debug("PAM: cleanup");
 273         if (sshpam_handle == NULL)
 274                 return;
 275         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 276         if (sshpam_cred_established) {
 277                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 278                 sshpam_cred_established = 0;
 279         }
 280         if (sshpam_session_open) {
 281                 pam_close_session(sshpam_handle, PAM_SILENT);
 282                 sshpam_session_open = 0;
 283         }
 284         sshpam_authenticated = sshpam_new_authtok_reqd = 0;
 285         pam_end(sshpam_handle, sshpam_err);
 286         sshpam_handle = NULL;
 287 }
 288
 289 static int
 290 sshpam_init(const char *user)
 291 {
 292         extern u_int utmp_len;
 293         extern char *__progname;
 294         const char *pam_rhost, *pam_user;
 295
 296         if (sshpam_handle != NULL) {
 297                 /* We already have a PAM context; check if the user matches */
 298                 sshpam_err = pam_get_item(sshpam_handle,
 299                     PAM_USER, (const void **)&pam_user);
 300                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 301                         return (0);
 302                 fatal_remove_cleanup(sshpam_cleanup, NULL);
 303                 pam_end(sshpam_handle, sshpam_err);
 304                 sshpam_handle = NULL;
 305         }
 306         debug("PAM: initializing for \"%s\"", user);
 307         sshpam_err =
 308             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 309         if (sshpam_err != PAM_SUCCESS) {
 310                 pam_end(sshpam_handle, sshpam_err);
 311                 sshpam_handle = NULL;
 312                 return (-1);
 313         }
 314         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 315         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 316         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 317         if (sshpam_err != PAM_SUCCESS) {
 318                 pam_end(sshpam_handle, sshpam_err);
 319                 sshpam_handle = NULL;
 320                 return (-1);
 321         }
 322 #ifdef PAM_TTY_KLUDGE
 323         /*
 324          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 325          * sshd doesn't set the tty until too late in the auth process and
 326          * may not even set one (for tty-less connections)
 327          */
 328         debug("PAM: setting PAM_TTY to \"ssh\"");
 329         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 330         if (sshpam_err != PAM_SUCCESS) {
 331                 pam_end(sshpam_handle, sshpam_err);
 332                 sshpam_handle = NULL;
 333                 return (-1);
 334         }
 335 #endif
 336         fatal_add_cleanup(sshpam_cleanup, NULL);
 337         return (0);
 338 }
 339
 340 static void *
 341 sshpam_init_ctx(Authctxt *authctxt)
 342 {
 343         struct pam_ctxt *ctxt;
 344         int socks[2];
 345
 346         /* Refuse to start if we don't have PAM enabled */
 347         if (!options.use_pam)
 348                 return NULL;
 349
 350         /* Initialize PAM */
 351         if (sshpam_init(authctxt->user) == -1) {
 352                 error("PAM: initialization failed");
 353                 return (NULL);
 354         }
 355
 356         ctxt = xmalloc(sizeof *ctxt);
 357         ctxt->pam_done = 0;
 358
 359         /* Start the authentication thread */
 360         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 361                 error("PAM: failed create sockets: %s", strerror(errno));
 362                 xfree(ctxt);
 363                 return (NULL);
 364         }
 365         ctxt->pam_psock = socks[0];
 366         ctxt->pam_csock = socks[1];
 367         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 368                 error("PAM: failed to start authentication thread: %s",
 369                     strerror(errno));
 370                 close(socks[0]);
 371                 close(socks[1]);
 372                 xfree(ctxt);
 373                 return (NULL);
 374         }
 375         fatal_add_cleanup(sshpam_thread_cleanup, ctxt);
 376         return (ctxt);
 377 }
 378
 379 static int
 380 sshpam_query(void *ctx, char **name, char **info,
 381     u_int *num, char ***prompts, u_int **echo_on)
 382 {
 383         Buffer buffer;
 384         struct pam_ctxt *ctxt = ctx;
 385         size_t plen;
 386         u_char type;
 387         char *msg;
 388         size_t len;
 389
 390         buffer_init(&buffer);
 391         *name = xstrdup("");
 392         *info = xstrdup("");
 393         *prompts = xmalloc(sizeof(char *));
 394         **prompts = NULL;
 395         plen = 0;
 396         *echo_on = xmalloc(sizeof(u_int));
 397         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 398                 type = buffer_get_char(&buffer);
 399                 msg = buffer_get_string(&buffer, NULL);
 400                 switch (type) {
 401                 case PAM_PROMPT_ECHO_ON:
 402                 case PAM_PROMPT_ECHO_OFF:
 403                         *num = 1;
 404                         len = plen + strlen(msg) + 1;
 405                         **prompts = xrealloc(**prompts, len);
 406                         plen += snprintf(**prompts + plen, len, "%s", msg);
 407                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 408                         xfree(msg);
 409                         return (0);
 410                 case PAM_ERROR_MSG:
 411                 case PAM_TEXT_INFO:
 412                         /* accumulate messages */
 413                         len = plen + strlen(msg) + 1;
 414                         **prompts = xrealloc(**prompts, len);
 415                         plen += snprintf(**prompts + plen, len, "%s", msg);
 416                         xfree(msg);
 417                         break;
 418                 case PAM_SUCCESS:
 419                 case PAM_AUTH_ERR:
 420                         if (**prompts != NULL) {
 421                                 /* drain any accumulated messages */
 422 #if 0 /* XXX - not compatible with privsep */
 423                                 packet_start(SSH2_MSG_USERAUTH_BANNER);
 424                                 packet_put_cstring(**prompts);
 425                                 packet_put_cstring("");
 426                                 packet_send();
 427                                 packet_write_wait();
 428 #endif
 429                                 xfree(**prompts);
 430                                 **prompts = NULL;
 431                         }
 432                         if (type == PAM_SUCCESS) {
 433                                 *num = 0;
 434                                 **echo_on = 0;
 435                                 ctxt->pam_done = 1;
 436                                 xfree(msg);
 437                                 return (0);
 438                         }
 439                         error("PAM: %s", msg);
 440                 default:
 441                         *num = 0;
 442                         **echo_on = 0;
 443                         xfree(msg);
 444                         ctxt->pam_done = -1;
 445                         return (-1);
 446                 }
 447         }
 448         return (-1);
 449 }
 450
 451 /* XXX - see also comment in auth-chall.c:verify_response */
 452 static int
 453 sshpam_respond(void *ctx, u_int num, char **resp)
 454 {
 455         Buffer buffer;
 456         struct pam_ctxt *ctxt = ctx;
 457
 458         debug2("PAM: %s", __func__);
 459         switch (ctxt->pam_done) {
 460         case 1:
 461                 sshpam_authenticated = 1;
 462                 return (0);
 463         case 0:
 464                 break;
 465         default:
 466                 return (-1);
 467         }
 468         if (num != 1) {
 469                 error("PAM: expected one response, got %u", num);
 470                 return (-1);
 471         }
 472         buffer_init(&buffer);
 473         buffer_put_cstring(&buffer, *resp);
 474         ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer);
 475         buffer_free(&buffer);
 476         return (1);
 477 }
 478
 479 static void
 480 sshpam_free_ctx(void *ctxtp)
 481 {
 482         struct pam_ctxt *ctxt = ctxtp;
 483
 484         fatal_remove_cleanup(sshpam_thread_cleanup, ctxt);
 485         sshpam_thread_cleanup(ctxtp);
 486         xfree(ctxt);
 487         /*
 488          * We don't call sshpam_cleanup() here because we may need the PAM
 489          * handle at a later stage, e.g. when setting up a session.  It's
 490          * still on the cleanup list, so pam_end() *will* be called before
 491          * the server process terminates.
 492          */
 493 }
 494
 495 KbdintDevice sshpam_device = {
 496         "pam",
 497         sshpam_init_ctx,
 498         sshpam_query,
 499         sshpam_respond,
 500         sshpam_free_ctx
 501 };
 502
 503 KbdintDevice mm_sshpam_device = {
 504         "pam",
 505         mm_sshpam_init_ctx,
 506         mm_sshpam_query,
 507         mm_sshpam_respond,
 508         mm_sshpam_free_ctx
 509 };
 510
 511 /*
 512  * This replaces auth-pam.c
 513  */
 514 void
 515 start_pam(const char *user)
 516 {
 517         if (!options.use_pam)
 518                 fatal("PAM: initialisation requested when UsePAM=no");
 519
 520         if (sshpam_init(user) == -1)
 521                 fatal("PAM: initialisation failed");
 522 }
 523
 524 void
 525 finish_pam(void)
 526 {
 527         fatal_remove_cleanup(sshpam_cleanup, NULL);
 528         sshpam_cleanup(NULL);
 529 }
 530
 531 u_int
 532 do_pam_account(void)
 533 {
 534         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 535         debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);
 536
 537         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
 538                 return (0);
 539
 540         if (sshpam_err == PAM_NEW_AUTHTOK_REQD) {
 541                 sshpam_new_authtok_reqd = 1;
 542
 543                 /* Prevent forwardings until password changed */
 544                 no_port_forwarding_flag |= 2;
 545                 no_agent_forwarding_flag |= 2;
 546                 no_x11_forwarding_flag |= 2;
 547         }
 548
 549         return (1);
 550 }
 551
 552 void
 553 do_pam_session(void)
 554 {
 555         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 556             (const void *)&null_conv);
 557         if (sshpam_err != PAM_SUCCESS)
 558                 fatal("PAM: failed to set PAM_CONV: %s",
 559                     pam_strerror(sshpam_handle, sshpam_err));
 560         sshpam_err = pam_open_session(sshpam_handle, 0);
 561         if (sshpam_err != PAM_SUCCESS)
 562                 fatal("PAM: pam_open_session(): %s",
 563                     pam_strerror(sshpam_handle, sshpam_err));
 564         sshpam_session_open = 1;
 565 }
 566
 567 void
 568 do_pam_set_tty(const char *tty)
 569 {
 570         if (tty != NULL) {
 571                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 572                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 573                 if (sshpam_err != PAM_SUCCESS)
 574                         fatal("PAM: failed to set PAM_TTY: %s",
 575                             pam_strerror(sshpam_handle, sshpam_err));
 576         }
 577 }
 578
 579 void
 580 do_pam_setcred(int init)
 581 {
 582         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 583             (const void *)&null_conv);
 584         if (sshpam_err != PAM_SUCCESS)
 585                 fatal("PAM: failed to set PAM_CONV: %s",
 586                     pam_strerror(sshpam_handle, sshpam_err));
 587         if (init) {
 588                 debug("PAM: establishing credentials");
 589                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 590         } else {
 591                 debug("PAM: reinitializing credentials");
 592                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 593         }
 594         if (sshpam_err == PAM_SUCCESS) {
 595                 sshpam_cred_established = 1;
 596                 return;
 597         }
 598         if (sshpam_authenticated)
 599                 fatal("PAM: pam_setcred(): %s",
 600                     pam_strerror(sshpam_handle, sshpam_err));
 601         else
 602                 debug("PAM: pam_setcred(): %s",
 603                     pam_strerror(sshpam_handle, sshpam_err));
 604 }
 605
 606 int
 607 is_pam_password_change_required(void)
 608 {
 609         return (sshpam_new_authtok_reqd);
 610 }
 611
 612 static int
 613 pam_chauthtok_conv(int n, const struct pam_message **msg,
 614     struct pam_response **resp, void *data)
 615 {
 616         char input[PAM_MAX_MSG_SIZE];
 617         struct pam_response *reply;
 618         int i;
 619
 620         *resp = NULL;
 621
 622         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 623                 return (PAM_CONV_ERR);
 624
 625         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 626                 return (PAM_CONV_ERR);
 627         memset(reply, 0, n * sizeof(*reply));
 628
 629         for (i = 0; i < n; ++i) {
 630                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 631                 case PAM_PROMPT_ECHO_OFF:
 632                         reply[i].resp =
 633                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 634                             RP_ALLOW_STDIN);
 635                         reply[i].resp_retcode = PAM_SUCCESS;
 636                         break;
 637                 case PAM_PROMPT_ECHO_ON:
 638                         fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
 639                         fgets(input, sizeof input, stdin);
 640                         reply[i].resp = xstrdup(input);
 641                         reply[i].resp_retcode = PAM_SUCCESS;
 642                         break;
 643                 case PAM_ERROR_MSG:
 644                 case PAM_TEXT_INFO:
 645                         fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
 646                         reply[i].resp_retcode = PAM_SUCCESS;
 647                         break;
 648                 default:
 649                         goto fail;
 650                 }
 651         }
 652         *resp = reply;
 653         return (PAM_SUCCESS);
 654
 655  fail:
 656         for(i = 0; i < n; i++) {
 657                 if (reply[i].resp != NULL)
 658                         xfree(reply[i].resp);
 659         }
 660         xfree(reply);
 661         return (PAM_CONV_ERR);
 662 }
 663
 664 /*
 665  * XXX this should be done in the authentication phase, but ssh1 doesn't
 666  * support that
 667  */
 668 void
 669 do_pam_chauthtok(void)
 670 {
 671         struct pam_conv pam_conv;
 672
 673         pam_conv.conv = pam_chauthtok_conv;
 674         pam_conv.appdata_ptr = NULL;
 675
 676         if (use_privsep)
 677                 fatal("Password expired (unable to change with privsep)");
 678         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 679             (const void *)&pam_conv);
 680         if (sshpam_err != PAM_SUCCESS)
 681                 fatal("PAM: failed to set PAM_CONV: %s",
 682                     pam_strerror(sshpam_handle, sshpam_err));
 683         debug("PAM: changing password");
 684         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 685         if (sshpam_err != PAM_SUCCESS)
 686                 fatal("PAM: pam_chauthtok(): %s",
 687                     pam_strerror(sshpam_handle, sshpam_err));
 688 }
 689
 690 /*
 691  * Set a PAM environment string. We need to do this so that the session
 692  * modules can handle things like Kerberos/GSI credentials that appear
 693  * during the ssh authentication process.
 694  */
 695
 696 int
 697 do_pam_putenv(char *name, char *value)
 698 {
 699         int ret = 1;
 700 #ifdef HAVE_PAM_PUTENV
 701         char *compound;
 702         size_t len;
 703
 704         len = strlen(name) + strlen(value) + 2;
 705         compound = xmalloc(len);
 706
 707         snprintf(compound, len, "%s=%s", name, value);
 708         ret = pam_putenv(sshpam_handle, compound);
 709         xfree(compound);
 710 #endif
 711
 712         return (ret);
 713 }
 714
 715 void
 716 print_pam_messages(void)
 717 {
 718         /* XXX */
 719 }
 720
 721 char **
 722 fetch_pam_environment(void)
 723 {
 724 #ifdef HAVE_PAM_GETENVLIST
 725         debug("PAM: retrieving environment");
 726         return (pam_getenvlist(sshpam_handle));
 727 #else
 728         return (NULL);
 729 #endif
 730 }
 731
 732 void
 733 free_pam_environment(char **env)
 734 {
 735         char **envp;
 736
 737         if (env == NULL)
 738                 return;
 739
 740         for (envp = env; *envp; envp++)
 741                 xfree(*envp);
 742         xfree(env);
 743 }
 744
 745 #endif /* USE_PAM */