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 static struct pam_ctxt *cleanup_ctxt;
 130
 131 /*
 132  * Conversation function for authentication thread.
 133  */
 134 static int
 135 sshpam_thread_conv(int n, const struct pam_message **msg,
 136     struct pam_response **resp, void *data)
 137 {
 138         Buffer buffer;
 139         struct pam_ctxt *ctxt;
 140         struct pam_response *reply;
 141         int i;
 142
 143         *resp = NULL;
 144
 145         ctxt = data;
 146         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 147                 return (PAM_CONV_ERR);
 148
 149         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 150                 return (PAM_CONV_ERR);
 151         memset(reply, 0, n * sizeof(*reply));
 152
 153         buffer_init(&buffer);
 154         for (i = 0; i < n; ++i) {
 155                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 156                 case PAM_PROMPT_ECHO_OFF:
 157                         buffer_put_cstring(&buffer,
 158                             PAM_MSG_MEMBER(msg, i, msg));
 159                         if (ssh_msg_send(ctxt->pam_csock,
 160                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 161                                 goto fail;
 162                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 163                                 goto fail;
 164                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 165                                 goto fail;
 166                         reply[i].resp = buffer_get_string(&buffer, NULL);
 167                         break;
 168                 case PAM_PROMPT_ECHO_ON:
 169                         buffer_put_cstring(&buffer,
 170                             PAM_MSG_MEMBER(msg, i, msg));
 171                         if (ssh_msg_send(ctxt->pam_csock,
 172                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 173                                 goto fail;
 174                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 175                                 goto fail;
 176                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 177                                 goto fail;
 178                         reply[i].resp = buffer_get_string(&buffer, NULL);
 179                         break;
 180                 case PAM_ERROR_MSG:
 181                         buffer_put_cstring(&buffer,
 182                             PAM_MSG_MEMBER(msg, i, msg));
 183                         if (ssh_msg_send(ctxt->pam_csock,
 184                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 185                                 goto fail;
 186                         break;
 187                 case PAM_TEXT_INFO:
 188                         buffer_put_cstring(&buffer,
 189                             PAM_MSG_MEMBER(msg, i, msg));
 190                         if (ssh_msg_send(ctxt->pam_csock,
 191                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 192                                 goto fail;
 193                         break;
 194                 default:
 195                         goto fail;
 196                 }
 197                 buffer_clear(&buffer);
 198         }
 199         buffer_free(&buffer);
 200         *resp = reply;
 201         return (PAM_SUCCESS);
 202
 203  fail:
 204         for(i = 0; i < n; i++) {
 205                 if (reply[i].resp != NULL)
 206                         xfree(reply[i].resp);
 207         }
 208         xfree(reply);
 209         buffer_free(&buffer);
 210         return (PAM_CONV_ERR);
 211 }
 212
 213 /*
 214  * Authentication thread.
 215  */
 216 static void *
 217 sshpam_thread(void *ctxtp)
 218 {
 219         struct pam_ctxt *ctxt = ctxtp;
 220         Buffer buffer;
 221         struct pam_conv sshpam_conv;
 222 #ifndef USE_POSIX_THREADS
 223         const char *pam_user;
 224
 225         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 226         setproctitle("%s [pam]", pam_user);
 227 #endif
 228
 229         sshpam_conv.conv = sshpam_thread_conv;
 230         sshpam_conv.appdata_ptr = ctxt;
 231
 232         buffer_init(&buffer);
 233         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 234             (const void *)&sshpam_conv);
 235         if (sshpam_err != PAM_SUCCESS)
 236                 goto auth_fail;
 237         sshpam_err = pam_authenticate(sshpam_handle, 0);
 238         if (sshpam_err != PAM_SUCCESS)
 239                 goto auth_fail;
 240         buffer_put_cstring(&buffer, "OK");
 241         /* XXX - can't do much about an error here */
 242         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 243         buffer_free(&buffer);
 244         pthread_exit(NULL);
 245
 246  auth_fail:
 247         buffer_put_cstring(&buffer,
 248             pam_strerror(sshpam_handle, sshpam_err));
 249         /* XXX - can't do much about an error here */
 250         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 251         buffer_free(&buffer);
 252         pthread_exit(NULL);
 253
 254         return (NULL); /* Avoid warning for non-pthread case */
 255 }
 256
 257 void
 258 sshpam_thread_cleanup(void)
 259 {
 260         struct pam_ctxt *ctxt = cleanup_ctxt;
 261
 262         if (ctxt != NULL && ctxt->pam_thread != 0) {
 263                 pthread_cancel(ctxt->pam_thread);
 264                 pthread_join(ctxt->pam_thread, NULL);
 265                 close(ctxt->pam_psock);
 266                 close(ctxt->pam_csock);
 267                 memset(ctxt, 0, sizeof(*ctxt));
 268                 cleanup_ctxt = NULL;
 269         }
 270 }
 271
 272 static int
 273 sshpam_null_conv(int n, const struct pam_message **msg,
 274     struct pam_response **resp, void *data)
 275 {
 276         return (PAM_CONV_ERR);
 277 }
 278
 279 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 280
 281 void
 282 sshpam_cleanup(void)
 283 {
 284         debug("PAM: cleanup");
 285         if (sshpam_handle == NULL)
 286                 return;
 287         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 288         if (sshpam_cred_established) {
 289                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 290                 sshpam_cred_established = 0;
 291         }
 292         if (sshpam_session_open) {
 293                 pam_close_session(sshpam_handle, PAM_SILENT);
 294                 sshpam_session_open = 0;
 295         }
 296         sshpam_authenticated = sshpam_new_authtok_reqd = 0;
 297         pam_end(sshpam_handle, sshpam_err);
 298         sshpam_handle = NULL;
 299 }
 300
 301 static int
 302 sshpam_init(const char *user)
 303 {
 304         extern u_int utmp_len;
 305         extern char *__progname;
 306         const char *pam_rhost, *pam_user;
 307
 308         if (sshpam_handle != NULL) {
 309                 /* We already have a PAM context; check if the user matches */
 310                 sshpam_err = pam_get_item(sshpam_handle,
 311                     PAM_USER, (const void **)&pam_user);
 312                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 313                         return (0);
 314                 pam_end(sshpam_handle, sshpam_err);
 315                 sshpam_handle = NULL;
 316         }
 317         debug("PAM: initializing for \"%s\"", user);
 318         sshpam_err =
 319             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 320         if (sshpam_err != PAM_SUCCESS) {
 321                 pam_end(sshpam_handle, sshpam_err);
 322                 sshpam_handle = NULL;
 323                 return (-1);
 324         }
 325         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 326         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 327         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 328         if (sshpam_err != PAM_SUCCESS) {
 329                 pam_end(sshpam_handle, sshpam_err);
 330                 sshpam_handle = NULL;
 331                 return (-1);
 332         }
 333 #ifdef PAM_TTY_KLUDGE
 334         /*
 335          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 336          * sshd doesn't set the tty until too late in the auth process and
 337          * may not even set one (for tty-less connections)
 338          */
 339         debug("PAM: setting PAM_TTY to \"ssh\"");
 340         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 341         if (sshpam_err != PAM_SUCCESS) {
 342                 pam_end(sshpam_handle, sshpam_err);
 343                 sshpam_handle = NULL;
 344                 return (-1);
 345         }
 346 #endif
 347         return (0);
 348 }
 349
 350 static void *
 351 sshpam_init_ctx(Authctxt *authctxt)
 352 {
 353         struct pam_ctxt *ctxt;
 354         int socks[2];
 355
 356         /* Refuse to start if we don't have PAM enabled */
 357         if (!options.use_pam)
 358                 return NULL;
 359
 360         /* Initialize PAM */
 361         if (sshpam_init(authctxt->user) == -1) {
 362                 error("PAM: initialization failed");
 363                 return (NULL);
 364         }
 365
 366         ctxt = xmalloc(sizeof *ctxt);
 367         memset(ctxt, 0, sizeof(*ctxt));
 368
 369         /* Start the authentication thread */
 370         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 371                 error("PAM: failed create sockets: %s", strerror(errno));
 372                 xfree(ctxt);
 373                 return (NULL);
 374         }
 375         ctxt->pam_psock = socks[0];
 376         ctxt->pam_csock = socks[1];
 377         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 378                 error("PAM: failed to start authentication thread: %s",
 379                     strerror(errno));
 380                 close(socks[0]);
 381                 close(socks[1]);
 382                 xfree(ctxt);
 383                 return (NULL);
 384         }
 385         cleanup_ctxt = ctxt;
 386         return (ctxt);
 387 }
 388
 389 static int
 390 sshpam_query(void *ctx, char **name, char **info,
 391     u_int *num, char ***prompts, u_int **echo_on)
 392 {
 393         Buffer buffer;
 394         struct pam_ctxt *ctxt = ctx;
 395         size_t plen;
 396         u_char type;
 397         char *msg;
 398         size_t len;
 399
 400         buffer_init(&buffer);
 401         *name = xstrdup("");
 402         *info = xstrdup("");
 403         *prompts = xmalloc(sizeof(char *));
 404         **prompts = NULL;
 405         plen = 0;
 406         *echo_on = xmalloc(sizeof(u_int));
 407         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 408                 type = buffer_get_char(&buffer);
 409                 msg = buffer_get_string(&buffer, NULL);
 410                 switch (type) {
 411                 case PAM_PROMPT_ECHO_ON:
 412                 case PAM_PROMPT_ECHO_OFF:
 413                         *num = 1;
 414                         len = plen + strlen(msg) + 1;
 415                         **prompts = xrealloc(**prompts, len);
 416                         plen += snprintf(**prompts + plen, len, "%s", msg);
 417                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 418                         xfree(msg);
 419                         return (0);
 420                 case PAM_ERROR_MSG:
 421                 case PAM_TEXT_INFO:
 422                         /* accumulate messages */
 423                         len = plen + strlen(msg) + 2;
 424                         **prompts = xrealloc(**prompts, len);
 425                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 426                         xfree(msg);
 427                         break;
 428                 case PAM_SUCCESS:
 429                 case PAM_AUTH_ERR:
 430                         if (**prompts != NULL) {
 431                                 /* drain any accumulated messages */
 432 #if 0 /* XXX - not compatible with privsep */
 433                                 packet_start(SSH2_MSG_USERAUTH_BANNER);
 434                                 packet_put_cstring(**prompts);
 435                                 packet_put_cstring("");
 436                                 packet_send();
 437                                 packet_write_wait();
 438 #endif
 439                                 xfree(**prompts);
 440                                 **prompts = NULL;
 441                         }
 442                         if (type == PAM_SUCCESS) {
 443                                 *num = 0;
 444                                 **echo_on = 0;
 445                                 ctxt->pam_done = 1;
 446                                 xfree(msg);
 447                                 return (0);
 448                         }
 449                         error("PAM: %s", msg);
 450                         /* FALLTHROUGH */
 451                 default:
 452                         *num = 0;
 453                         **echo_on = 0;
 454                         xfree(msg);
 455                         ctxt->pam_done = -1;
 456                         return (-1);
 457                 }
 458         }
 459         return (-1);
 460 }
 461
 462 /* XXX - see also comment in auth-chall.c:verify_response */
 463 static int
 464 sshpam_respond(void *ctx, u_int num, char **resp)
 465 {
 466         Buffer buffer;
 467         struct pam_ctxt *ctxt = ctx;
 468
 469         debug2("PAM: %s", __func__);
 470         switch (ctxt->pam_done) {
 471         case 1:
 472                 sshpam_authenticated = 1;
 473                 return (0);
 474         case 0:
 475                 break;
 476         default:
 477                 return (-1);
 478         }
 479         if (num != 1) {
 480                 error("PAM: expected one response, got %u", num);
 481                 return (-1);
 482         }
 483         buffer_init(&buffer);
 484         buffer_put_cstring(&buffer, *resp);
 485         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 486                 buffer_free(&buffer);
 487                 return (-1);
 488         }
 489         buffer_free(&buffer);
 490         return (1);
 491 }
 492
 493 static void
 494 sshpam_free_ctx(void *ctxtp)
 495 {
 496         struct pam_ctxt *ctxt = ctxtp;
 497
 498         sshpam_thread_cleanup();
 499         xfree(ctxt);
 500         /*
 501          * We don't call sshpam_cleanup() here because we may need the PAM
 502          * handle at a later stage, e.g. when setting up a session.  It's
 503          * still on the cleanup list, so pam_end() *will* be called before
 504          * the server process terminates.
 505          */
 506 }
 507
 508 KbdintDevice sshpam_device = {
 509         "pam",
 510         sshpam_init_ctx,
 511         sshpam_query,
 512         sshpam_respond,
 513         sshpam_free_ctx
 514 };
 515
 516 KbdintDevice mm_sshpam_device = {
 517         "pam",
 518         mm_sshpam_init_ctx,
 519         mm_sshpam_query,
 520         mm_sshpam_respond,
 521         mm_sshpam_free_ctx
 522 };
 523
 524 /*
 525  * This replaces auth-pam.c
 526  */
 527 void
 528 start_pam(const char *user)
 529 {
 530         if (!options.use_pam)
 531                 fatal("PAM: initialisation requested when UsePAM=no");
 532
 533         if (sshpam_init(user) == -1)
 534                 fatal("PAM: initialisation failed");
 535 }
 536
 537 void
 538 finish_pam(void)
 539 {
 540         sshpam_cleanup();
 541 }
 542
 543 u_int
 544 do_pam_account(void)
 545 {
 546         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 547         debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);
 548
 549         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
 550                 return (0);
 551
 552         if (sshpam_err == PAM_NEW_AUTHTOK_REQD) {
 553                 sshpam_new_authtok_reqd = 1;
 554
 555                 /* Prevent forwardings until password changed */
 556                 no_port_forwarding_flag |= 2;
 557                 no_agent_forwarding_flag |= 2;
 558                 no_x11_forwarding_flag |= 2;
 559         }
 560
 561         return (1);
 562 }
 563
 564 void
 565 do_pam_session(void)
 566 {
 567         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 568             (const void *)&null_conv);
 569         if (sshpam_err != PAM_SUCCESS)
 570                 fatal("PAM: failed to set PAM_CONV: %s",
 571                     pam_strerror(sshpam_handle, sshpam_err));
 572         sshpam_err = pam_open_session(sshpam_handle, 0);
 573         if (sshpam_err != PAM_SUCCESS)
 574                 fatal("PAM: pam_open_session(): %s",
 575                     pam_strerror(sshpam_handle, sshpam_err));
 576         sshpam_session_open = 1;
 577 }
 578
 579 void
 580 do_pam_set_tty(const char *tty)
 581 {
 582         if (tty != NULL) {
 583                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 584                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 585                 if (sshpam_err != PAM_SUCCESS)
 586                         fatal("PAM: failed to set PAM_TTY: %s",
 587                             pam_strerror(sshpam_handle, sshpam_err));
 588         }
 589 }
 590
 591 void
 592 do_pam_setcred(int init)
 593 {
 594         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 595             (const void *)&null_conv);
 596         if (sshpam_err != PAM_SUCCESS)
 597                 fatal("PAM: failed to set PAM_CONV: %s",
 598                     pam_strerror(sshpam_handle, sshpam_err));
 599         if (init) {
 600                 debug("PAM: establishing credentials");
 601                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 602         } else {
 603                 debug("PAM: reinitializing credentials");
 604                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 605         }
 606         if (sshpam_err == PAM_SUCCESS) {
 607                 sshpam_cred_established = 1;
 608                 return;
 609         }
 610         if (sshpam_authenticated)
 611                 fatal("PAM: pam_setcred(): %s",
 612                     pam_strerror(sshpam_handle, sshpam_err));
 613         else
 614                 debug("PAM: pam_setcred(): %s",
 615                     pam_strerror(sshpam_handle, sshpam_err));
 616 }
 617
 618 int
 619 is_pam_password_change_required(void)
 620 {
 621         return (sshpam_new_authtok_reqd);
 622 }
 623
 624 static int
 625 pam_chauthtok_conv(int n, const struct pam_message **msg,
 626     struct pam_response **resp, void *data)
 627 {
 628         char input[PAM_MAX_MSG_SIZE];
 629         struct pam_response *reply;
 630         int i;
 631
 632         *resp = NULL;
 633
 634         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 635                 return (PAM_CONV_ERR);
 636
 637         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 638                 return (PAM_CONV_ERR);
 639         memset(reply, 0, n * sizeof(*reply));
 640
 641         for (i = 0; i < n; ++i) {
 642                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 643                 case PAM_PROMPT_ECHO_OFF:
 644                         reply[i].resp =
 645                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 646                             RP_ALLOW_STDIN);
 647                         reply[i].resp_retcode = PAM_SUCCESS;
 648                         break;
 649                 case PAM_PROMPT_ECHO_ON:
 650                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 651                         fgets(input, sizeof input, stdin);
 652                         reply[i].resp = xstrdup(input);
 653                         reply[i].resp_retcode = PAM_SUCCESS;
 654                         break;
 655                 case PAM_ERROR_MSG:
 656                 case PAM_TEXT_INFO:
 657                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 658                         reply[i].resp_retcode = PAM_SUCCESS;
 659                         break;
 660                 default:
 661                         goto fail;
 662                 }
 663         }
 664         *resp = reply;
 665         return (PAM_SUCCESS);
 666
 667  fail:
 668         for(i = 0; i < n; i++) {
 669                 if (reply[i].resp != NULL)
 670                         xfree(reply[i].resp);
 671         }
 672         xfree(reply);
 673         return (PAM_CONV_ERR);
 674 }
 675
 676 /*
 677  * XXX this should be done in the authentication phase, but ssh1 doesn't
 678  * support that
 679  */
 680 void
 681 do_pam_chauthtok(void)
 682 {
 683         struct pam_conv pam_conv;
 684
 685         pam_conv.conv = pam_chauthtok_conv;
 686         pam_conv.appdata_ptr = NULL;
 687
 688         if (use_privsep)
 689                 fatal("Password expired (unable to change with privsep)");
 690         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 691             (const void *)&pam_conv);
 692         if (sshpam_err != PAM_SUCCESS)
 693                 fatal("PAM: failed to set PAM_CONV: %s",
 694                     pam_strerror(sshpam_handle, sshpam_err));
 695         debug("PAM: changing password");
 696         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 697         if (sshpam_err != PAM_SUCCESS)
 698                 fatal("PAM: pam_chauthtok(): %s",
 699                     pam_strerror(sshpam_handle, sshpam_err));
 700 }
 701
 702 /*
 703  * Set a PAM environment string. We need to do this so that the session
 704  * modules can handle things like Kerberos/GSI credentials that appear
 705  * during the ssh authentication process.
 706  */
 707
 708 int
 709 do_pam_putenv(char *name, char *value)
 710 {
 711         int ret = 1;
 712 #ifdef HAVE_PAM_PUTENV
 713         char *compound;
 714         size_t len;
 715
 716         len = strlen(name) + strlen(value) + 2;
 717         compound = xmalloc(len);
 718
 719         snprintf(compound, len, "%s=%s", name, value);
 720         ret = pam_putenv(sshpam_handle, compound);
 721         xfree(compound);
 722 #endif
 723
 724         return (ret);
 725 }
 726
 727 void
 728 print_pam_messages(void)
 729 {
 730         /* XXX */
 731 }
 732
 733 char **
 734 fetch_pam_environment(void)
 735 {
 736 #ifdef HAVE_PAM_GETENVLIST
 737         debug("PAM: retrieving environment");
 738         return (pam_getenvlist(sshpam_handle));
 739 #else
 740         return (NULL);
 741 #endif
 742 }
 743
 744 void
 745 free_pam_environment(char **env)
 746 {
 747         char **envp;
 748
 749         if (env == NULL)
 750                 return;
 751
 752         for (envp = env; *envp; envp++)
 753                 xfree(*envp);
 754         xfree(env);
 755 }
 756
 757 #endif /* USE_PAM */