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 #ifdef HAVE_PAM_PUTENV
 171                 /* Errors are not fatal here */
 172                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 173                         error("PAM: pam_putenv: %s",
 174                             pam_strerror(sshpam_handle, sshpam_err));
 175                 }
 176 #endif
 177         }
 178 }
 179
 180 /*
 181  * Conversation function for authentication thread.
 182  */
 183 static int
 184 sshpam_thread_conv(int n, const struct pam_message **msg,
 185     struct pam_response **resp, void *data)
 186 {
 187         Buffer buffer;
 188         struct pam_ctxt *ctxt;
 189         struct pam_response *reply;
 190         int i;
 191
 192         *resp = NULL;
 193
 194         ctxt = data;
 195         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 196                 return (PAM_CONV_ERR);
 197
 198         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 199                 return (PAM_CONV_ERR);
 200         memset(reply, 0, n * sizeof(*reply));
 201
 202         buffer_init(&buffer);
 203         for (i = 0; i < n; ++i) {
 204                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 205                 case PAM_PROMPT_ECHO_OFF:
 206                         buffer_put_cstring(&buffer,
 207                             PAM_MSG_MEMBER(msg, i, msg));
 208                         if (ssh_msg_send(ctxt->pam_csock,
 209                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 210                                 goto fail;
 211                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 212                                 goto fail;
 213                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 214                                 goto fail;
 215                         reply[i].resp = buffer_get_string(&buffer, NULL);
 216                         break;
 217                 case PAM_PROMPT_ECHO_ON:
 218                         buffer_put_cstring(&buffer,
 219                             PAM_MSG_MEMBER(msg, i, msg));
 220                         if (ssh_msg_send(ctxt->pam_csock,
 221                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 222                                 goto fail;
 223                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 224                                 goto fail;
 225                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 226                                 goto fail;
 227                         reply[i].resp = buffer_get_string(&buffer, NULL);
 228                         break;
 229                 case PAM_ERROR_MSG:
 230                         buffer_put_cstring(&buffer,
 231                             PAM_MSG_MEMBER(msg, i, msg));
 232                         if (ssh_msg_send(ctxt->pam_csock,
 233                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 234                                 goto fail;
 235                         break;
 236                 case PAM_TEXT_INFO:
 237                         buffer_put_cstring(&buffer,
 238                             PAM_MSG_MEMBER(msg, i, msg));
 239                         if (ssh_msg_send(ctxt->pam_csock,
 240                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 241                                 goto fail;
 242                         break;
 243                 default:
 244                         goto fail;
 245                 }
 246                 buffer_clear(&buffer);
 247         }
 248         buffer_free(&buffer);
 249         *resp = reply;
 250         return (PAM_SUCCESS);
 251
 252  fail:
 253         for(i = 0; i < n; i++) {
 254                 if (reply[i].resp != NULL)
 255                         xfree(reply[i].resp);
 256         }
 257         xfree(reply);
 258         buffer_free(&buffer);
 259         return (PAM_CONV_ERR);
 260 }
 261
 262 /*
 263  * Authentication thread.
 264  */
 265 static void *
 266 sshpam_thread(void *ctxtp)
 267 {
 268         struct pam_ctxt *ctxt = ctxtp;
 269         Buffer buffer;
 270         struct pam_conv sshpam_conv;
 271 #ifndef USE_POSIX_THREADS
 272         extern char **environ;
 273         char **env_from_pam;
 274         u_int i;
 275         const char *pam_user;
 276
 277         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 278         setproctitle("%s [pam]", pam_user);
 279         environ[0] = NULL;
 280 #endif
 281
 282         sshpam_conv.conv = sshpam_thread_conv;
 283         sshpam_conv.appdata_ptr = ctxt;
 284
 285         buffer_init(&buffer);
 286         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 287             (const void *)&sshpam_conv);
 288         if (sshpam_err != PAM_SUCCESS)
 289                 goto auth_fail;
 290         sshpam_err = pam_authenticate(sshpam_handle, 0);
 291         if (sshpam_err != PAM_SUCCESS)
 292                 goto auth_fail;
 293         buffer_put_cstring(&buffer, "OK");
 294
 295 #ifndef USE_POSIX_THREADS
 296         /* Export any environment strings set in child */
 297         for(i = 0; environ[i] != NULL; i++)
 298                 ; /* Count */
 299         buffer_put_int(&buffer, i);
 300         for(i = 0; environ[i] != NULL; i++)
 301                 buffer_put_cstring(&buffer, environ[i]);
 302
 303         /* Export any environment strings set by PAM in child */
 304         env_from_pam = pam_getenvlist(sshpam_handle);
 305         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 306                 ; /* Count */
 307         buffer_put_int(&buffer, i);
 308         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 309                 buffer_put_cstring(&buffer, env_from_pam[i]);
 310 #endif /* USE_POSIX_THREADS */
 311
 312         /* XXX - can't do much about an error here */
 313         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 314         buffer_free(&buffer);
 315         pthread_exit(NULL);
 316
 317  auth_fail:
 318         buffer_put_cstring(&buffer,
 319             pam_strerror(sshpam_handle, sshpam_err));
 320         /* XXX - can't do much about an error here */
 321         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 322         buffer_free(&buffer);
 323         pthread_exit(NULL);
 324
 325         return (NULL); /* Avoid warning for non-pthread case */
 326 }
 327
 328 void
 329 sshpam_thread_cleanup(void)
 330 {
 331         struct pam_ctxt *ctxt = cleanup_ctxt;
 332
 333         if (ctxt != NULL && ctxt->pam_thread != 0) {
 334                 pthread_cancel(ctxt->pam_thread);
 335                 pthread_join(ctxt->pam_thread, NULL);
 336                 close(ctxt->pam_psock);
 337                 close(ctxt->pam_csock);
 338                 memset(ctxt, 0, sizeof(*ctxt));
 339                 cleanup_ctxt = NULL;
 340         }
 341 }
 342
 343 static int
 344 sshpam_null_conv(int n, const struct pam_message **msg,
 345     struct pam_response **resp, void *data)
 346 {
 347         return (PAM_CONV_ERR);
 348 }
 349
 350 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 351
 352 void
 353 sshpam_cleanup(void)
 354 {
 355         debug("PAM: cleanup");
 356         if (sshpam_handle == NULL)
 357                 return;
 358         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 359         if (sshpam_cred_established) {
 360                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 361                 sshpam_cred_established = 0;
 362         }
 363         if (sshpam_session_open) {
 364                 pam_close_session(sshpam_handle, PAM_SILENT);
 365                 sshpam_session_open = 0;
 366         }
 367         sshpam_authenticated = sshpam_new_authtok_reqd = 0;
 368         pam_end(sshpam_handle, sshpam_err);
 369         sshpam_handle = NULL;
 370 }
 371
 372 static int
 373 sshpam_init(const char *user)
 374 {
 375         extern u_int utmp_len;
 376         extern char *__progname;
 377         const char *pam_rhost, *pam_user;
 378
 379         if (sshpam_handle != NULL) {
 380                 /* We already have a PAM context; check if the user matches */
 381                 sshpam_err = pam_get_item(sshpam_handle,
 382                     PAM_USER, (const void **)&pam_user);
 383                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 384                         return (0);
 385                 pam_end(sshpam_handle, sshpam_err);
 386                 sshpam_handle = NULL;
 387         }
 388         debug("PAM: initializing for \"%s\"", user);
 389         sshpam_err =
 390             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 391         if (sshpam_err != PAM_SUCCESS) {
 392                 pam_end(sshpam_handle, sshpam_err);
 393                 sshpam_handle = NULL;
 394                 return (-1);
 395         }
 396         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 397         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 398         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 399         if (sshpam_err != PAM_SUCCESS) {
 400                 pam_end(sshpam_handle, sshpam_err);
 401                 sshpam_handle = NULL;
 402                 return (-1);
 403         }
 404 #ifdef PAM_TTY_KLUDGE
 405         /*
 406          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 407          * sshd doesn't set the tty until too late in the auth process and
 408          * may not even set one (for tty-less connections)
 409          */
 410         debug("PAM: setting PAM_TTY to \"ssh\"");
 411         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 412         if (sshpam_err != PAM_SUCCESS) {
 413                 pam_end(sshpam_handle, sshpam_err);
 414                 sshpam_handle = NULL;
 415                 return (-1);
 416         }
 417 #endif
 418         return (0);
 419 }
 420
 421 static void *
 422 sshpam_init_ctx(Authctxt *authctxt)
 423 {
 424         struct pam_ctxt *ctxt;
 425         int socks[2];
 426
 427         /* Refuse to start if we don't have PAM enabled */
 428         if (!options.use_pam)
 429                 return NULL;
 430
 431         /* Initialize PAM */
 432         if (sshpam_init(authctxt->user) == -1) {
 433                 error("PAM: initialization failed");
 434                 return (NULL);
 435         }
 436
 437         ctxt = xmalloc(sizeof *ctxt);
 438         memset(ctxt, 0, sizeof(*ctxt));
 439
 440         /* Start the authentication thread */
 441         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 442                 error("PAM: failed create sockets: %s", strerror(errno));
 443                 xfree(ctxt);
 444                 return (NULL);
 445         }
 446         ctxt->pam_psock = socks[0];
 447         ctxt->pam_csock = socks[1];
 448         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 449                 error("PAM: failed to start authentication thread: %s",
 450                     strerror(errno));
 451                 close(socks[0]);
 452                 close(socks[1]);
 453                 xfree(ctxt);
 454                 return (NULL);
 455         }
 456         cleanup_ctxt = ctxt;
 457         return (ctxt);
 458 }
 459
 460 static int
 461 sshpam_query(void *ctx, char **name, char **info,
 462     u_int *num, char ***prompts, u_int **echo_on)
 463 {
 464         Buffer buffer;
 465         struct pam_ctxt *ctxt = ctx;
 466         size_t plen;
 467         u_char type;
 468         char *msg;
 469         size_t len;
 470
 471         buffer_init(&buffer);
 472         *name = xstrdup("");
 473         *info = xstrdup("");
 474         *prompts = xmalloc(sizeof(char *));
 475         **prompts = NULL;
 476         plen = 0;
 477         *echo_on = xmalloc(sizeof(u_int));
 478         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 479                 type = buffer_get_char(&buffer);
 480                 msg = buffer_get_string(&buffer, NULL);
 481                 switch (type) {
 482                 case PAM_PROMPT_ECHO_ON:
 483                 case PAM_PROMPT_ECHO_OFF:
 484                         *num = 1;
 485                         len = plen + strlen(msg) + 1;
 486                         **prompts = xrealloc(**prompts, len);
 487                         plen += snprintf(**prompts + plen, len, "%s", msg);
 488                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 489                         xfree(msg);
 490                         return (0);
 491                 case PAM_ERROR_MSG:
 492                 case PAM_TEXT_INFO:
 493                         /* accumulate messages */
 494                         len = plen + strlen(msg) + 2;
 495                         **prompts = xrealloc(**prompts, len);
 496                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 497                         xfree(msg);
 498                         break;
 499                 case PAM_SUCCESS:
 500                 case PAM_AUTH_ERR:
 501                         if (**prompts != NULL) {
 502                                 /* drain any accumulated messages */
 503                                 debug("PAM: %s", **prompts);
 504                                 buffer_append(&loginmsg, **prompts,
 505                                     strlen(**prompts));
 506                                 xfree(**prompts);
 507                                 **prompts = NULL;
 508                         }
 509                         if (type == PAM_SUCCESS) {
 510                                 import_environments(&buffer);
 511                                 *num = 0;
 512                                 **echo_on = 0;
 513                                 ctxt->pam_done = 1;
 514                                 xfree(msg);
 515                                 return (0);
 516                         }
 517                         error("PAM: %s", msg);
 518                         /* FALLTHROUGH */
 519                 default:
 520                         *num = 0;
 521                         **echo_on = 0;
 522                         xfree(msg);
 523                         ctxt->pam_done = -1;
 524                         return (-1);
 525                 }
 526         }
 527         return (-1);
 528 }
 529
 530 /* XXX - see also comment in auth-chall.c:verify_response */
 531 static int
 532 sshpam_respond(void *ctx, u_int num, char **resp)
 533 {
 534         Buffer buffer;
 535         struct pam_ctxt *ctxt = ctx;
 536
 537         debug2("PAM: %s", __func__);
 538         switch (ctxt->pam_done) {
 539         case 1:
 540                 sshpam_authenticated = 1;
 541                 return (0);
 542         case 0:
 543                 break;
 544         default:
 545                 return (-1);
 546         }
 547         if (num != 1) {
 548                 error("PAM: expected one response, got %u", num);
 549                 return (-1);
 550         }
 551         buffer_init(&buffer);
 552         buffer_put_cstring(&buffer, *resp);
 553         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 554                 buffer_free(&buffer);
 555                 return (-1);
 556         }
 557         buffer_free(&buffer);
 558         return (1);
 559 }
 560
 561 static void
 562 sshpam_free_ctx(void *ctxtp)
 563 {
 564         struct pam_ctxt *ctxt = ctxtp;
 565
 566         sshpam_thread_cleanup();
 567         xfree(ctxt);
 568         /*
 569          * We don't call sshpam_cleanup() here because we may need the PAM
 570          * handle at a later stage, e.g. when setting up a session.  It's
 571          * still on the cleanup list, so pam_end() *will* be called before
 572          * the server process terminates.
 573          */
 574 }
 575
 576 KbdintDevice sshpam_device = {
 577         "pam",
 578         sshpam_init_ctx,
 579         sshpam_query,
 580         sshpam_respond,
 581         sshpam_free_ctx
 582 };
 583
 584 KbdintDevice mm_sshpam_device = {
 585         "pam",
 586         mm_sshpam_init_ctx,
 587         mm_sshpam_query,
 588         mm_sshpam_respond,
 589         mm_sshpam_free_ctx
 590 };
 591
 592 /*
 593  * This replaces auth-pam.c
 594  */
 595 void
 596 start_pam(const char *user)
 597 {
 598         if (!options.use_pam)
 599                 fatal("PAM: initialisation requested when UsePAM=no");
 600
 601         if (sshpam_init(user) == -1)
 602                 fatal("PAM: initialisation failed");
 603 }
 604
 605 void
 606 finish_pam(void)
 607 {
 608         sshpam_cleanup();
 609 }
 610
 611 u_int
 612 do_pam_account(void)
 613 {
 614         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 615         debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);
 616
 617         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
 618                 return (0);
 619
 620         if (sshpam_err == PAM_NEW_AUTHTOK_REQD) {
 621                 sshpam_new_authtok_reqd = 1;
 622
 623                 /* Prevent forwardings until password changed */
 624                 no_port_forwarding_flag |= 2;
 625                 no_agent_forwarding_flag |= 2;
 626                 no_x11_forwarding_flag |= 2;
 627         }
 628
 629         return (1);
 630 }
 631
 632 void
 633 do_pam_set_tty(const char *tty)
 634 {
 635         if (tty != NULL) {
 636                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 637                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 638                 if (sshpam_err != PAM_SUCCESS)
 639                         fatal("PAM: failed to set PAM_TTY: %s",
 640                             pam_strerror(sshpam_handle, sshpam_err));
 641         }
 642 }
 643
 644 void
 645 do_pam_setcred(int init)
 646 {
 647         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 648             (const void *)&null_conv);
 649         if (sshpam_err != PAM_SUCCESS)
 650                 fatal("PAM: failed to set PAM_CONV: %s",
 651                     pam_strerror(sshpam_handle, sshpam_err));
 652         if (init) {
 653                 debug("PAM: establishing credentials");
 654                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 655         } else {
 656                 debug("PAM: reinitializing credentials");
 657                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 658         }
 659         if (sshpam_err == PAM_SUCCESS) {
 660                 sshpam_cred_established = 1;
 661                 return;
 662         }
 663         if (sshpam_authenticated)
 664                 fatal("PAM: pam_setcred(): %s",
 665                     pam_strerror(sshpam_handle, sshpam_err));
 666         else
 667                 debug("PAM: pam_setcred(): %s",
 668                     pam_strerror(sshpam_handle, sshpam_err));
 669 }
 670
 671 int
 672 is_pam_password_change_required(void)
 673 {
 674         return (sshpam_new_authtok_reqd);
 675 }
 676
 677 static int
 678 pam_tty_conv(int n, const struct pam_message **msg,
 679     struct pam_response **resp, void *data)
 680 {
 681         char input[PAM_MAX_MSG_SIZE];
 682         struct pam_response *reply;
 683         int i;
 684
 685         *resp = NULL;
 686
 687         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
 688                 return (PAM_CONV_ERR);
 689
 690         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 691                 return (PAM_CONV_ERR);
 692         memset(reply, 0, n * sizeof(*reply));
 693
 694         for (i = 0; i < n; ++i) {
 695                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 696                 case PAM_PROMPT_ECHO_OFF:
 697                         reply[i].resp =
 698                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 699                             RP_ALLOW_STDIN);
 700                         reply[i].resp_retcode = PAM_SUCCESS;
 701                         break;
 702                 case PAM_PROMPT_ECHO_ON:
 703                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 704                         fgets(input, sizeof input, stdin);
 705                         reply[i].resp = xstrdup(input);
 706                         reply[i].resp_retcode = PAM_SUCCESS;
 707                         break;
 708                 case PAM_ERROR_MSG:
 709                 case PAM_TEXT_INFO:
 710                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 711                         reply[i].resp_retcode = PAM_SUCCESS;
 712                         break;
 713                 default:
 714                         goto fail;
 715                 }
 716         }
 717         *resp = reply;
 718         return (PAM_SUCCESS);
 719
 720  fail:
 721         for(i = 0; i < n; i++) {
 722                 if (reply[i].resp != NULL)
 723                         xfree(reply[i].resp);
 724         }
 725         xfree(reply);
 726         return (PAM_CONV_ERR);
 727 }
 728
 729 static struct pam_conv tty_conv = { pam_tty_conv, NULL };
 730
 731 /*
 732  * XXX this should be done in the authentication phase, but ssh1 doesn't
 733  * support that
 734  */
 735 void
 736 do_pam_chauthtok(void)
 737 {
 738         if (use_privsep)
 739                 fatal("Password expired (unable to change with privsep)");
 740         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 741             (const void *)&tty_conv);
 742         if (sshpam_err != PAM_SUCCESS)
 743                 fatal("PAM: failed to set PAM_CONV: %s",
 744                     pam_strerror(sshpam_handle, sshpam_err));
 745         debug("PAM: changing password");
 746         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 747         if (sshpam_err != PAM_SUCCESS)
 748                 fatal("PAM: pam_chauthtok(): %s",
 749                     pam_strerror(sshpam_handle, sshpam_err));
 750 }
 751
 752 void
 753 do_pam_session(void)
 754 {
 755         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 756             (const void *)&tty_conv);
 757         if (sshpam_err != PAM_SUCCESS)
 758                 fatal("PAM: failed to set PAM_CONV: %s",
 759                     pam_strerror(sshpam_handle, sshpam_err));
 760         sshpam_err = pam_open_session(sshpam_handle, 0);
 761         if (sshpam_err != PAM_SUCCESS)
 762                 fatal("PAM: pam_open_session(): %s",
 763                     pam_strerror(sshpam_handle, sshpam_err));
 764         sshpam_session_open = 1;
 765 }
 766
 767 /*
 768  * Set a PAM environment string. We need to do this so that the session
 769  * modules can handle things like Kerberos/GSI credentials that appear
 770  * during the ssh authentication process.
 771  */
 772 int
 773 do_pam_putenv(char *name, char *value)
 774 {
 775         int ret = 1;
 776 #ifdef HAVE_PAM_PUTENV
 777         char *compound;
 778         size_t len;
 779
 780         len = strlen(name) + strlen(value) + 2;
 781         compound = xmalloc(len);
 782
 783         snprintf(compound, len, "%s=%s", name, value);
 784         ret = pam_putenv(sshpam_handle, compound);
 785         xfree(compound);
 786 #endif
 787
 788         return (ret);
 789 }
 790
 791 void
 792 print_pam_messages(void)
 793 {
 794         /* XXX */
 795 }
 796
 797 char **
 798 fetch_pam_child_environment(void)
 799 {
 800         return sshpam_env;
 801 }
 802
 803 char **
 804 fetch_pam_environment(void)
 805 {
 806         return (pam_getenvlist(sshpam_handle));
 807 }
 808
 809 void
 810 free_pam_environment(char **env)
 811 {
 812         char **envp;
 813
 814         if (env == NULL)
 815                 return;
 816
 817         for (envp = env; *envp; envp++)
 818                 xfree(*envp);
 819         xfree(env);
 820 }
 821
 822 #endif /* USE_PAM */