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 extern Buffer loginmsg;
  56
  57 #define __unused
  58
  59 #ifdef USE_POSIX_THREADS
  60 #include <pthread.h>
  61 /*
  62  * Avoid namespace clash when *not* using pthreads for systems *with*
  63  * pthreads, which unconditionally define pthread_t via sys/types.h
  64  * (e.g. Linux)
  65  */
  66 typedef pthread_t sp_pthread_t;
  67 #else
  68 /*
  69  * Simulate threads with processes.
  70  */
  71 typedef pid_t sp_pthread_t;
  72
  73 static void
  74 pthread_exit(void *value __unused)
  75 {
  76         _exit(0);
  77 }
  78
  79 static int
  80 pthread_create(sp_pthread_t *thread, const void *attr __unused,
  81     void *(*thread_start)(void *), void *arg)
  82 {
  83         pid_t pid;
  84
  85         switch ((pid = fork())) {
  86         case -1:
  87                 error("fork(): %s", strerror(errno));
  88                 return (-1);
  89         case 0:
  90                 thread_start(arg);
  91                 _exit(1);
  92         default:
  93                 *thread = pid;
  94                 return (0);
  95         }
  96 }
  97
  98 static int
  99 pthread_cancel(sp_pthread_t thread)
 100 {
 101         return (kill(thread, SIGTERM));
 102 }
 103
 104 static int
 105 pthread_join(sp_pthread_t thread, void **value __unused)
 106 {
 107         int status;
 108
 109         waitpid(thread, &status, 0);
 110         return (status);
 111 }
 112 #endif
 113
 114
 115 static pam_handle_t *sshpam_handle = NULL;
 116 static int sshpam_err = 0;
 117 static int sshpam_authenticated = 0;
 118 static int sshpam_new_authtok_reqd = 0;
 119 static int sshpam_session_open = 0;
 120 static int sshpam_cred_established = 0;
 121 static char **sshpam_env = NULL;
 122
 123 struct pam_ctxt {
 124         sp_pthread_t     pam_thread;
 125         int              pam_psock;
 126         int              pam_csock;
 127         int              pam_done;
 128 };
 129
 130 static void sshpam_free_ctx(void *);
 131 static struct pam_ctxt *cleanup_ctxt;
 132
 133 /* Some PAM implementations don't implement this */
 134 #ifndef HAVE_PAM_GETENVLIST
 135 static char **
 136 pam_getenvlist(pam_handle_t *pamh)
 137 {
 138         /*
 139          * XXX - If necessary, we can still support envrionment passing
 140          * for platforms without pam_getenvlist by searching for known
 141          * env vars (e.g. KRB5CCNAME) from the PAM environment.
 142          */
 143          return NULL;
 144 }
 145 #endif
 146
 147 /* Import regular and PAM environment from subprocess */
 148 static void
 149 import_environments(Buffer *b)
 150 {
 151         char *env;
 152         u_int i, num_env;
 153         int err;
 154
 155         /* Import environment from subprocess */
 156         num_env = buffer_get_int(b);
 157         sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
 158         debug3("PAM: num env strings %d", num_env);
 159         for(i = 0; i < num_env; i++)
 160                 sshpam_env[i] = buffer_get_string(b, NULL);
 161
 162         sshpam_env[num_env] = NULL;
 163
 164         /* Import PAM environment from subprocess */
 165         num_env = buffer_get_int(b);
 166         debug("PAM: num PAM env strings %d", num_env);
 167         for(i = 0; i < num_env; i++) {
 168                 env = buffer_get_string(b, NULL);
 169
 170                 /* Errors are not fatal here */
 171                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 172                         error("PAM: pam_putenv: %s",
 173                             pam_strerror(sshpam_handle, sshpam_err));
 174                 }
 175         }
 176 }
 177
 178 /*
 179  * Conversation function for authentication thread.
 180  */
 181 static int
 182 sshpam_thread_conv(int n, const struct pam_message **msg,
 183     struct pam_response **resp, void *data)
 184 {
 185         Buffer buffer;
 186         struct pam_ctxt *ctxt;
 187         struct pam_response *reply;
 188         int i;
 189
 190         *resp = NULL;
 191
 192         ctxt = data;
 193         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 194                 return (PAM_CONV_ERR);
 195
 196         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 197                 return (PAM_CONV_ERR);
 198         memset(reply, 0, n * sizeof(*reply));
 199
 200         buffer_init(&buffer);
 201         for (i = 0; i < n; ++i) {
 202                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 203                 case PAM_PROMPT_ECHO_OFF:
 204                         buffer_put_cstring(&buffer,
 205                             PAM_MSG_MEMBER(msg, i, msg));
 206                         if (ssh_msg_send(ctxt->pam_csock,
 207                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 208                                 goto fail;
 209                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 210                                 goto fail;
 211                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 212                                 goto fail;
 213                         reply[i].resp = buffer_get_string(&buffer, NULL);
 214                         break;
 215                 case PAM_PROMPT_ECHO_ON:
 216                         buffer_put_cstring(&buffer,
 217                             PAM_MSG_MEMBER(msg, i, msg));
 218                         if (ssh_msg_send(ctxt->pam_csock,
 219                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 220                                 goto fail;
 221                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 222                                 goto fail;
 223                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 224                                 goto fail;
 225                         reply[i].resp = buffer_get_string(&buffer, NULL);
 226                         break;
 227                 case PAM_ERROR_MSG:
 228                         buffer_put_cstring(&buffer,
 229                             PAM_MSG_MEMBER(msg, i, msg));
 230                         if (ssh_msg_send(ctxt->pam_csock,
 231                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 232                                 goto fail;
 233                         break;
 234                 case PAM_TEXT_INFO:
 235                         buffer_put_cstring(&buffer,
 236                             PAM_MSG_MEMBER(msg, i, msg));
 237                         if (ssh_msg_send(ctxt->pam_csock,
 238                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 239                                 goto fail;
 240                         break;
 241                 default:
 242                         goto fail;
 243                 }
 244                 buffer_clear(&buffer);
 245         }
 246         buffer_free(&buffer);
 247         *resp = reply;
 248         return (PAM_SUCCESS);
 249
 250  fail:
 251         for(i = 0; i < n; i++) {
 252                 if (reply[i].resp != NULL)
 253                         xfree(reply[i].resp);
 254         }
 255         xfree(reply);
 256         buffer_free(&buffer);
 257         return (PAM_CONV_ERR);
 258 }
 259
 260 /*
 261  * Authentication thread.
 262  */
 263 static void *
 264 sshpam_thread(void *ctxtp)
 265 {
 266         struct pam_ctxt *ctxt = ctxtp;
 267         Buffer buffer;
 268         struct pam_conv sshpam_conv;
 269 #ifndef USE_POSIX_THREADS
 270         extern char **environ;
 271         char **env_from_pam;
 272         u_int i;
 273         const char *pam_user;
 274
 275         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 276         setproctitle("%s [pam]", pam_user);
 277         environ[0] = NULL;
 278 #endif
 279
 280         sshpam_conv.conv = sshpam_thread_conv;
 281         sshpam_conv.appdata_ptr = ctxt;
 282
 283         buffer_init(&buffer);
 284         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 285             (const void *)&sshpam_conv);
 286         if (sshpam_err != PAM_SUCCESS)
 287                 goto auth_fail;
 288         sshpam_err = pam_authenticate(sshpam_handle, 0);
 289         if (sshpam_err != PAM_SUCCESS)
 290                 goto auth_fail;
 291         buffer_put_cstring(&buffer, "OK");
 292
 293 #ifndef USE_POSIX_THREADS
 294         /* Export any environment strings set in child */
 295         for(i = 0; environ[i] != NULL; i++)
 296                 ; /* Count */
 297         buffer_put_int(&buffer, i);
 298         for(i = 0; environ[i] != NULL; i++)
 299                 buffer_put_cstring(&buffer, environ[i]);
 300
 301         /* Export any environment strings set by PAM in child */
 302         env_from_pam = pam_getenvlist(sshpam_handle);
 303         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 304                 ; /* Count */
 305         buffer_put_int(&buffer, i);
 306         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 307                 buffer_put_cstring(&buffer, env_from_pam[i]);
 308 #endif /* USE_POSIX_THREADS */
 309
 310         /* XXX - can't do much about an error here */
 311         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 312         buffer_free(&buffer);
 313         pthread_exit(NULL);
 314
 315  auth_fail:
 316         buffer_put_cstring(&buffer,
 317             pam_strerror(sshpam_handle, sshpam_err));
 318         /* XXX - can't do much about an error here */
 319         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 320         buffer_free(&buffer);
 321         pthread_exit(NULL);
 322
 323         return (NULL); /* Avoid warning for non-pthread case */
 324 }
 325
 326 void
 327 sshpam_thread_cleanup(void)
 328 {
 329         struct pam_ctxt *ctxt = cleanup_ctxt;
 330
 331         if (ctxt != NULL && ctxt->pam_thread != 0) {
 332                 pthread_cancel(ctxt->pam_thread);
 333                 pthread_join(ctxt->pam_thread, NULL);
 334                 close(ctxt->pam_psock);
 335                 close(ctxt->pam_csock);
 336                 memset(ctxt, 0, sizeof(*ctxt));
 337                 cleanup_ctxt = NULL;
 338         }
 339 }
 340
 341 static int
 342 sshpam_null_conv(int n, const struct pam_message **msg,
 343     struct pam_response **resp, void *data)
 344 {
 345         return (PAM_CONV_ERR);
 346 }
 347
 348 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 349
 350 void
 351 sshpam_cleanup(void)
 352 {
 353         debug("PAM: cleanup");
 354         if (sshpam_handle == NULL)
 355                 return;
 356         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 357         if (sshpam_cred_established) {
 358                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 359                 sshpam_cred_established = 0;
 360         }
 361         if (sshpam_session_open) {
 362                 pam_close_session(sshpam_handle, PAM_SILENT);
 363                 sshpam_session_open = 0;
 364         }
 365         sshpam_authenticated = sshpam_new_authtok_reqd = 0;
 366         pam_end(sshpam_handle, sshpam_err);
 367         sshpam_handle = NULL;
 368 }
 369
 370 static int
 371 sshpam_init(const char *user)
 372 {
 373         extern u_int utmp_len;
 374         extern char *__progname;
 375         const char *pam_rhost, *pam_user;
 376
 377         if (sshpam_handle != NULL) {
 378                 /* We already have a PAM context; check if the user matches */
 379                 sshpam_err = pam_get_item(sshpam_handle,
 380                     PAM_USER, (const void **)&pam_user);
 381                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 382                         return (0);
 383                 pam_end(sshpam_handle, sshpam_err);
 384                 sshpam_handle = NULL;
 385         }
 386         debug("PAM: initializing for \"%s\"", user);
 387         sshpam_err =
 388             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 389         if (sshpam_err != PAM_SUCCESS) {
 390                 pam_end(sshpam_handle, sshpam_err);
 391                 sshpam_handle = NULL;
 392                 return (-1);
 393         }
 394         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 395         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 396         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 397         if (sshpam_err != PAM_SUCCESS) {
 398                 pam_end(sshpam_handle, sshpam_err);
 399                 sshpam_handle = NULL;
 400                 return (-1);
 401         }
 402 #ifdef PAM_TTY_KLUDGE
 403         /*
 404          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 405          * sshd doesn't set the tty until too late in the auth process and
 406          * may not even set one (for tty-less connections)
 407          */
 408         debug("PAM: setting PAM_TTY to \"ssh\"");
 409         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 410         if (sshpam_err != PAM_SUCCESS) {
 411                 pam_end(sshpam_handle, sshpam_err);
 412                 sshpam_handle = NULL;
 413                 return (-1);
 414         }
 415 #endif
 416         return (0);
 417 }
 418
 419 static void *
 420 sshpam_init_ctx(Authctxt *authctxt)
 421 {
 422         struct pam_ctxt *ctxt;
 423         int socks[2];
 424
 425         /* Refuse to start if we don't have PAM enabled */
 426         if (!options.use_pam)
 427                 return NULL;
 428
 429         /* Initialize PAM */
 430         if (sshpam_init(authctxt->user) == -1) {
 431                 error("PAM: initialization failed");
 432                 return (NULL);
 433         }
 434
 435         ctxt = xmalloc(sizeof *ctxt);
 436         memset(ctxt, 0, sizeof(*ctxt));
 437
 438         /* Start the authentication thread */
 439         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 440                 error("PAM: failed create sockets: %s", strerror(errno));
 441                 xfree(ctxt);
 442                 return (NULL);
 443         }
 444         ctxt->pam_psock = socks[0];
 445         ctxt->pam_csock = socks[1];
 446         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 447                 error("PAM: failed to start authentication thread: %s",
 448                     strerror(errno));
 449                 close(socks[0]);
 450                 close(socks[1]);
 451                 xfree(ctxt);
 452                 return (NULL);
 453         }
 454         cleanup_ctxt = ctxt;
 455         return (ctxt);
 456 }
 457
 458 static int
 459 sshpam_query(void *ctx, char **name, char **info,
 460     u_int *num, char ***prompts, u_int **echo_on)
 461 {
 462         Buffer buffer;
 463         struct pam_ctxt *ctxt = ctx;
 464         size_t plen;
 465         u_char type;
 466         char *msg;
 467         size_t len;
 468
 469         buffer_init(&buffer);
 470         *name = xstrdup("");
 471         *info = xstrdup("");
 472         *prompts = xmalloc(sizeof(char *));
 473         **prompts = NULL;
 474         plen = 0;
 475         *echo_on = xmalloc(sizeof(u_int));
 476         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 477                 type = buffer_get_char(&buffer);
 478                 msg = buffer_get_string(&buffer, NULL);
 479                 switch (type) {
 480                 case PAM_PROMPT_ECHO_ON:
 481                 case PAM_PROMPT_ECHO_OFF:
 482                         *num = 1;
 483                         len = plen + strlen(msg) + 1;
 484                         **prompts = xrealloc(**prompts, len);
 485                         plen += snprintf(**prompts + plen, len, "%s", msg);
 486                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 487                         xfree(msg);
 488                         return (0);
 489                 case PAM_ERROR_MSG:
 490                 case PAM_TEXT_INFO:
 491                         /* accumulate messages */
 492                         len = plen + strlen(msg) + 2;
 493                         **prompts = xrealloc(**prompts, len);
 494                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 495                         xfree(msg);
 496                         break;
 497                 case PAM_SUCCESS:
 498                 case PAM_AUTH_ERR:
 499                         if (**prompts != NULL) {
 500                                 /* drain any accumulated messages */
 501                                 debug("PAM: %s", **prompts);
 502                                 buffer_append(&loginmsg, **prompts,
 503                                     strlen(**prompts));
 504                                 xfree(**prompts);
 505                                 **prompts = NULL;
 506                         }
 507                         if (type == PAM_SUCCESS) {
 508                                 import_environments(&buffer);
 509                                 *num = 0;
 510                                 **echo_on = 0;
 511                                 ctxt->pam_done = 1;
 512                                 xfree(msg);
 513                                 return (0);
 514                         }
 515                         error("PAM: %s", msg);
 516                         /* FALLTHROUGH */
 517                 default:
 518                         *num = 0;
 519                         **echo_on = 0;
 520                         xfree(msg);
 521                         ctxt->pam_done = -1;
 522                         return (-1);
 523                 }
 524         }
 525         return (-1);
 526 }
 527
 528 /* XXX - see also comment in auth-chall.c:verify_response */
 529 static int
 530 sshpam_respond(void *ctx, u_int num, char **resp)
 531 {
 532         Buffer buffer;
 533         struct pam_ctxt *ctxt = ctx;
 534
 535         debug2("PAM: %s", __func__);
 536         switch (ctxt->pam_done) {
 537         case 1:
 538                 sshpam_authenticated = 1;
 539                 return (0);
 540         case 0:
 541                 break;
 542         default:
 543                 return (-1);
 544         }
 545         if (num != 1) {
 546                 error("PAM: expected one response, got %u", num);
 547                 return (-1);
 548         }
 549         buffer_init(&buffer);
 550         buffer_put_cstring(&buffer, *resp);
 551         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 552                 buffer_free(&buffer);
 553                 return (-1);
 554         }
 555         buffer_free(&buffer);
 556         return (1);
 557 }
 558
 559 static void
 560 sshpam_free_ctx(void *ctxtp)
 561 {
 562         struct pam_ctxt *ctxt = ctxtp;
 563
 564         sshpam_thread_cleanup();
 565         xfree(ctxt);
 566         /*
 567          * We don't call sshpam_cleanup() here because we may need the PAM
 568          * handle at a later stage, e.g. when setting up a session.  It's
 569          * still on the cleanup list, so pam_end() *will* be called before
 570          * the server process terminates.
 571          */
 572 }
 573
 574 KbdintDevice sshpam_device = {
 575         "pam",
 576         sshpam_init_ctx,
 577         sshpam_query,
 578         sshpam_respond,
 579         sshpam_free_ctx
 580 };
 581
 582 KbdintDevice mm_sshpam_device = {
 583         "pam",
 584         mm_sshpam_init_ctx,
 585         mm_sshpam_query,
 586         mm_sshpam_respond,
 587         mm_sshpam_free_ctx
 588 };
 589
 590 /*
 591  * This replaces auth-pam.c
 592  */
 593 void
 594 start_pam(const char *user)
 595 {
 596         if (!options.use_pam)
 597                 fatal("PAM: initialisation requested when UsePAM=no");
 598
 599         if (sshpam_init(user) == -1)
 600                 fatal("PAM: initialisation failed");
 601 }
 602
 603 void
 604 finish_pam(void)
 605 {
 606         sshpam_cleanup();
 607 }
 608
 609 u_int
 610 do_pam_account(void)
 611 {
 612         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 613         debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);
 614
 615         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
 616                 return (0);
 617
 618         if (sshpam_err == PAM_NEW_AUTHTOK_REQD) {
 619                 sshpam_new_authtok_reqd = 1;
 620
 621                 /* Prevent forwardings until password changed */
 622                 no_port_forwarding_flag |= 2;
 623                 no_agent_forwarding_flag |= 2;
 624                 no_x11_forwarding_flag |= 2;
 625         }
 626
 627         return (1);
 628 }
 629
 630 void
 631 do_pam_set_tty(const char *tty)
 632 {
 633         if (tty != NULL) {
 634                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 635                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 636                 if (sshpam_err != PAM_SUCCESS)
 637                         fatal("PAM: failed to set PAM_TTY: %s",
 638                             pam_strerror(sshpam_handle, sshpam_err));
 639         }
 640 }
 641
 642 void
 643 do_pam_setcred(int init)
 644 {
 645         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 646             (const void *)&null_conv);
 647         if (sshpam_err != PAM_SUCCESS)
 648                 fatal("PAM: failed to set PAM_CONV: %s",
 649                     pam_strerror(sshpam_handle, sshpam_err));
 650         if (init) {
 651                 debug("PAM: establishing credentials");
 652                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 653         } else {
 654                 debug("PAM: reinitializing credentials");
 655                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 656         }
 657         if (sshpam_err == PAM_SUCCESS) {
 658                 sshpam_cred_established = 1;
 659                 return;
 660         }
 661         if (sshpam_authenticated)
 662                 fatal("PAM: pam_setcred(): %s",
 663                     pam_strerror(sshpam_handle, sshpam_err));
 664         else
 665                 debug("PAM: pam_setcred(): %s",
 666                     pam_strerror(sshpam_handle, sshpam_err));
 667 }
 668
 669 int
 670 is_pam_password_change_required(void)
 671 {
 672         return (sshpam_new_authtok_reqd);
 673 }
 674
 675 static int
 676 pam_tty_conv(int n, const struct pam_message **msg,
 677     struct pam_response **resp, void *data)
 678 {
 679         char input[PAM_MAX_MSG_SIZE];
 680         struct pam_response *reply;
 681         int i;
 682
 683         *resp = NULL;
 684
 685         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
 686                 return (PAM_CONV_ERR);
 687
 688         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 689                 return (PAM_CONV_ERR);
 690         memset(reply, 0, n * sizeof(*reply));
 691
 692         for (i = 0; i < n; ++i) {
 693                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 694                 case PAM_PROMPT_ECHO_OFF:
 695                         reply[i].resp =
 696                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 697                             RP_ALLOW_STDIN);
 698                         reply[i].resp_retcode = PAM_SUCCESS;
 699                         break;
 700                 case PAM_PROMPT_ECHO_ON:
 701                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 702                         fgets(input, sizeof input, stdin);
 703                         reply[i].resp = xstrdup(input);
 704                         reply[i].resp_retcode = PAM_SUCCESS;
 705                         break;
 706                 case PAM_ERROR_MSG:
 707                 case PAM_TEXT_INFO:
 708                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 709                         reply[i].resp_retcode = PAM_SUCCESS;
 710                         break;
 711                 default:
 712                         goto fail;
 713                 }
 714         }
 715         *resp = reply;
 716         return (PAM_SUCCESS);
 717
 718  fail:
 719         for(i = 0; i < n; i++) {
 720                 if (reply[i].resp != NULL)
 721                         xfree(reply[i].resp);
 722         }
 723         xfree(reply);
 724         return (PAM_CONV_ERR);
 725 }
 726
 727 static struct pam_conv tty_conv = { pam_tty_conv, NULL };
 728
 729 /*
 730  * XXX this should be done in the authentication phase, but ssh1 doesn't
 731  * support that
 732  */
 733 void
 734 do_pam_chauthtok(void)
 735 {
 736         if (use_privsep)
 737                 fatal("Password expired (unable to change with privsep)");
 738         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 739             (const void *)&tty_conv);
 740         if (sshpam_err != PAM_SUCCESS)
 741                 fatal("PAM: failed to set PAM_CONV: %s",
 742                     pam_strerror(sshpam_handle, sshpam_err));
 743         debug("PAM: changing password");
 744         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 745         if (sshpam_err != PAM_SUCCESS)
 746                 fatal("PAM: pam_chauthtok(): %s",
 747                     pam_strerror(sshpam_handle, sshpam_err));
 748 }
 749
 750 void
 751 do_pam_session(void)
 752 {
 753         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 754             (const void *)&tty_conv);
 755         if (sshpam_err != PAM_SUCCESS)
 756                 fatal("PAM: failed to set PAM_CONV: %s",
 757                     pam_strerror(sshpam_handle, sshpam_err));
 758         sshpam_err = pam_open_session(sshpam_handle, 0);
 759         if (sshpam_err != PAM_SUCCESS)
 760                 fatal("PAM: pam_open_session(): %s",
 761                     pam_strerror(sshpam_handle, sshpam_err));
 762         sshpam_session_open = 1;
 763 }
 764
 765 /*
 766  * Set a PAM environment string. We need to do this so that the session
 767  * modules can handle things like Kerberos/GSI credentials that appear
 768  * during the ssh authentication process.
 769  */
 770 int
 771 do_pam_putenv(char *name, char *value)
 772 {
 773         int ret = 1;
 774 #ifdef HAVE_PAM_PUTENV
 775         char *compound;
 776         size_t len;
 777
 778         len = strlen(name) + strlen(value) + 2;
 779         compound = xmalloc(len);
 780
 781         snprintf(compound, len, "%s=%s", name, value);
 782         ret = pam_putenv(sshpam_handle, compound);
 783         xfree(compound);
 784 #endif
 785
 786         return (ret);
 787 }
 788
 789 void
 790 print_pam_messages(void)
 791 {
 792         /* XXX */
 793 }
 794
 795 char **
 796 fetch_pam_child_environment(void)
 797 {
 798         return sshpam_env;
 799 }
 800
 801 char **
 802 fetch_pam_environment(void)
 803 {
 804         return (pam_getenvlist(sshpam_handle));
 805 }
 806
 807 void
 808 free_pam_environment(char **env)
 809 {
 810         char **envp;
 811
 812         if (env == NULL)
 813                 return;
 814
 815         for (envp = env; *envp; envp++)
 816                 xfree(*envp);
 817         xfree(env);
 818 }
 819
 820 #endif /* USE_PAM */