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 extern int compat20;
  57
  58 #define __unused
  59
  60 #ifdef USE_POSIX_THREADS
  61 #include <pthread.h>
  62 /*
  63  * Avoid namespace clash when *not* using pthreads for systems *with*
  64  * pthreads, which unconditionally define pthread_t via sys/types.h
  65  * (e.g. Linux)
  66  */
  67 typedef pthread_t sp_pthread_t;
  68 #else
  69 /*
  70  * Simulate threads with processes.
  71  */
  72 typedef pid_t sp_pthread_t;
  73
  74 static void
  75 pthread_exit(void *value __unused)
  76 {
  77         _exit(0);
  78 }
  79
  80 static int
  81 pthread_create(sp_pthread_t *thread, const void *attr __unused,
  82     void *(*thread_start)(void *), void *arg)
  83 {
  84         pid_t pid;
  85
  86         switch ((pid = fork())) {
  87         case -1:
  88                 error("fork(): %s", strerror(errno));
  89                 return (-1);
  90         case 0:
  91                 thread_start(arg);
  92                 _exit(1);
  93         default:
  94                 *thread = pid;
  95                 return (0);
  96         }
  97 }
  98
  99 static int
 100 pthread_cancel(sp_pthread_t thread)
 101 {
 102         return (kill(thread, SIGTERM));
 103 }
 104
 105 static int
 106 pthread_join(sp_pthread_t thread, void **value __unused)
 107 {
 108         int status;
 109
 110         waitpid(thread, &status, 0);
 111         return (status);
 112 }
 113 #endif
 114
 115
 116 static pam_handle_t *sshpam_handle = NULL;
 117 static int sshpam_err = 0;
 118 static int sshpam_authenticated = 0;
 119 static int sshpam_new_authtok_reqd = 0;
 120 static int sshpam_session_open = 0;
 121 static int sshpam_cred_established = 0;
 122 static int sshpam_account_status = -1;
 123 static char **sshpam_env = NULL;
 124
 125 struct pam_ctxt {
 126         sp_pthread_t     pam_thread;
 127         int              pam_psock;
 128         int              pam_csock;
 129         int              pam_done;
 130 };
 131
 132 static void sshpam_free_ctx(void *);
 133 static struct pam_ctxt *cleanup_ctxt;
 134
 135 /* Some PAM implementations don't implement this */
 136 #ifndef HAVE_PAM_GETENVLIST
 137 static char **
 138 pam_getenvlist(pam_handle_t *pamh)
 139 {
 140         /*
 141          * XXX - If necessary, we can still support envrionment passing
 142          * for platforms without pam_getenvlist by searching for known
 143          * env vars (e.g. KRB5CCNAME) from the PAM environment.
 144          */
 145          return NULL;
 146 }
 147 #endif
 148
 149 void
 150 pam_password_change_required(int reqd)
 151 {
 152         sshpam_new_authtok_reqd = reqd;
 153         if (reqd) {
 154                 no_port_forwarding_flag |= 2;
 155                 no_agent_forwarding_flag |= 2;
 156                 no_x11_forwarding_flag |= 2;
 157         } else {
 158                 no_port_forwarding_flag &= ~2;
 159                 no_agent_forwarding_flag &= ~2;
 160                 no_x11_forwarding_flag &= ~2;
 161
 162         }
 163 }
 164 /* Import regular and PAM environment from subprocess */
 165 static void
 166 import_environments(Buffer *b)
 167 {
 168         char *env;
 169         u_int i, num_env;
 170         int err;
 171
 172         /* Import variables set by do_pam_account */
 173         sshpam_account_status = buffer_get_int(b);
 174         pam_password_change_required(buffer_get_int(b));
 175
 176         /* Import environment from subprocess */
 177         num_env = buffer_get_int(b);
 178         sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
 179         debug3("PAM: num env strings %d", num_env);
 180         for(i = 0; i < num_env; i++)
 181                 sshpam_env[i] = buffer_get_string(b, NULL);
 182
 183         sshpam_env[num_env] = NULL;
 184
 185         /* Import PAM environment from subprocess */
 186         num_env = buffer_get_int(b);
 187         debug("PAM: num PAM env strings %d", num_env);
 188         for(i = 0; i < num_env; i++) {
 189                 env = buffer_get_string(b, NULL);
 190
 191 #ifdef HAVE_PAM_PUTENV
 192                 /* Errors are not fatal here */
 193                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 194                         error("PAM: pam_putenv: %s",
 195                             pam_strerror(sshpam_handle, sshpam_err));
 196                 }
 197 #endif
 198         }
 199 }
 200
 201 /*
 202  * Conversation function for authentication thread.
 203  */
 204 static int
 205 sshpam_thread_conv(int n, const struct pam_message **msg,
 206     struct pam_response **resp, void *data)
 207 {
 208         Buffer buffer;
 209         struct pam_ctxt *ctxt;
 210         struct pam_response *reply;
 211         int i;
 212
 213         *resp = NULL;
 214
 215         ctxt = data;
 216         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 217                 return (PAM_CONV_ERR);
 218
 219         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 220                 return (PAM_CONV_ERR);
 221         memset(reply, 0, n * sizeof(*reply));
 222
 223         buffer_init(&buffer);
 224         for (i = 0; i < n; ++i) {
 225                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 226                 case PAM_PROMPT_ECHO_OFF:
 227                         buffer_put_cstring(&buffer,
 228                             PAM_MSG_MEMBER(msg, i, msg));
 229                         if (ssh_msg_send(ctxt->pam_csock,
 230                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 231                                 goto fail;
 232                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 233                                 goto fail;
 234                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 235                                 goto fail;
 236                         reply[i].resp = buffer_get_string(&buffer, NULL);
 237                         break;
 238                 case PAM_PROMPT_ECHO_ON:
 239                         buffer_put_cstring(&buffer,
 240                             PAM_MSG_MEMBER(msg, i, msg));
 241                         if (ssh_msg_send(ctxt->pam_csock,
 242                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 243                                 goto fail;
 244                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 245                                 goto fail;
 246                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 247                                 goto fail;
 248                         reply[i].resp = buffer_get_string(&buffer, NULL);
 249                         break;
 250                 case PAM_ERROR_MSG:
 251                         buffer_put_cstring(&buffer,
 252                             PAM_MSG_MEMBER(msg, i, msg));
 253                         if (ssh_msg_send(ctxt->pam_csock,
 254                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 255                                 goto fail;
 256                         break;
 257                 case PAM_TEXT_INFO:
 258                         buffer_put_cstring(&buffer,
 259                             PAM_MSG_MEMBER(msg, i, msg));
 260                         if (ssh_msg_send(ctxt->pam_csock,
 261                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 262                                 goto fail;
 263                         break;
 264                 default:
 265                         goto fail;
 266                 }
 267                 buffer_clear(&buffer);
 268         }
 269         buffer_free(&buffer);
 270         *resp = reply;
 271         return (PAM_SUCCESS);
 272
 273  fail:
 274         for(i = 0; i < n; i++) {
 275                 if (reply[i].resp != NULL)
 276                         xfree(reply[i].resp);
 277         }
 278         xfree(reply);
 279         buffer_free(&buffer);
 280         return (PAM_CONV_ERR);
 281 }
 282
 283 /*
 284  * Authentication thread.
 285  */
 286 static void *
 287 sshpam_thread(void *ctxtp)
 288 {
 289         struct pam_ctxt *ctxt = ctxtp;
 290         Buffer buffer;
 291         struct pam_conv sshpam_conv;
 292 #ifndef USE_POSIX_THREADS
 293         extern char **environ;
 294         char **env_from_pam;
 295         u_int i;
 296         const char *pam_user;
 297
 298         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 299         setproctitle("%s [pam]", pam_user);
 300         environ[0] = NULL;
 301 #endif
 302
 303         sshpam_conv.conv = sshpam_thread_conv;
 304         sshpam_conv.appdata_ptr = ctxt;
 305
 306         buffer_init(&buffer);
 307         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 308             (const void *)&sshpam_conv);
 309         if (sshpam_err != PAM_SUCCESS)
 310                 goto auth_fail;
 311         sshpam_err = pam_authenticate(sshpam_handle, 0);
 312         if (sshpam_err != PAM_SUCCESS)
 313                 goto auth_fail;
 314
 315         if (compat20) {
 316                 if (!do_pam_account())
 317                         goto auth_fail;
 318                 if (sshpam_new_authtok_reqd) {
 319                         sshpam_err = pam_chauthtok(sshpam_handle,
 320                             PAM_CHANGE_EXPIRED_AUTHTOK);
 321                         if (sshpam_err != PAM_SUCCESS)
 322                                 goto auth_fail;
 323                         pam_password_change_required(0);
 324                 }
 325         }
 326
 327         buffer_put_cstring(&buffer, "OK");
 328
 329 #ifndef USE_POSIX_THREADS
 330         /* Export variables set by do_pam_account */
 331         buffer_put_int(&buffer, sshpam_account_status);
 332         buffer_put_int(&buffer, sshpam_new_authtok_reqd);
 333
 334         /* Export any environment strings set in child */
 335         for(i = 0; environ[i] != NULL; i++)
 336                 ; /* Count */
 337         buffer_put_int(&buffer, i);
 338         for(i = 0; environ[i] != NULL; i++)
 339                 buffer_put_cstring(&buffer, environ[i]);
 340
 341         /* Export any environment strings set by PAM in child */
 342         env_from_pam = pam_getenvlist(sshpam_handle);
 343         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 344                 ; /* Count */
 345         buffer_put_int(&buffer, i);
 346         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 347                 buffer_put_cstring(&buffer, env_from_pam[i]);
 348 #endif /* USE_POSIX_THREADS */
 349
 350         /* XXX - can't do much about an error here */
 351         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 352         buffer_free(&buffer);
 353         pthread_exit(NULL);
 354
 355  auth_fail:
 356         buffer_put_cstring(&buffer,
 357             pam_strerror(sshpam_handle, sshpam_err));
 358         /* XXX - can't do much about an error here */
 359         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 360         buffer_free(&buffer);
 361         pthread_exit(NULL);
 362
 363         return (NULL); /* Avoid warning for non-pthread case */
 364 }
 365
 366 void
 367 sshpam_thread_cleanup(void)
 368 {
 369         struct pam_ctxt *ctxt = cleanup_ctxt;
 370
 371         if (ctxt != NULL && ctxt->pam_thread != 0) {
 372                 pthread_cancel(ctxt->pam_thread);
 373                 pthread_join(ctxt->pam_thread, NULL);
 374                 close(ctxt->pam_psock);
 375                 close(ctxt->pam_csock);
 376                 memset(ctxt, 0, sizeof(*ctxt));
 377                 cleanup_ctxt = NULL;
 378         }
 379 }
 380
 381 static int
 382 sshpam_null_conv(int n, const struct pam_message **msg,
 383     struct pam_response **resp, void *data)
 384 {
 385         return (PAM_CONV_ERR);
 386 }
 387
 388 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 389
 390 void
 391 sshpam_cleanup(void)
 392 {
 393         debug("PAM: cleanup");
 394         if (sshpam_handle == NULL)
 395                 return;
 396         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 397         if (sshpam_cred_established) {
 398                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 399                 sshpam_cred_established = 0;
 400         }
 401         if (sshpam_session_open) {
 402                 pam_close_session(sshpam_handle, PAM_SILENT);
 403                 sshpam_session_open = 0;
 404         }
 405         sshpam_authenticated = sshpam_new_authtok_reqd = 0;
 406         pam_end(sshpam_handle, sshpam_err);
 407         sshpam_handle = NULL;
 408 }
 409
 410 static int
 411 sshpam_init(const char *user)
 412 {
 413         extern u_int utmp_len;
 414         extern char *__progname;
 415         const char *pam_rhost, *pam_user;
 416
 417         if (sshpam_handle != NULL) {
 418                 /* We already have a PAM context; check if the user matches */
 419                 sshpam_err = pam_get_item(sshpam_handle,
 420                     PAM_USER, (const void **)&pam_user);
 421                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 422                         return (0);
 423                 pam_end(sshpam_handle, sshpam_err);
 424                 sshpam_handle = NULL;
 425         }
 426         debug("PAM: initializing for \"%s\"", user);
 427         sshpam_err =
 428             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 429         if (sshpam_err != PAM_SUCCESS) {
 430                 pam_end(sshpam_handle, sshpam_err);
 431                 sshpam_handle = NULL;
 432                 return (-1);
 433         }
 434         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 435         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 436         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 437         if (sshpam_err != PAM_SUCCESS) {
 438                 pam_end(sshpam_handle, sshpam_err);
 439                 sshpam_handle = NULL;
 440                 return (-1);
 441         }
 442 #ifdef PAM_TTY_KLUDGE
 443         /*
 444          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 445          * sshd doesn't set the tty until too late in the auth process and
 446          * may not even set one (for tty-less connections)
 447          */
 448         debug("PAM: setting PAM_TTY to \"ssh\"");
 449         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 450         if (sshpam_err != PAM_SUCCESS) {
 451                 pam_end(sshpam_handle, sshpam_err);
 452                 sshpam_handle = NULL;
 453                 return (-1);
 454         }
 455 #endif
 456         return (0);
 457 }
 458
 459 static void *
 460 sshpam_init_ctx(Authctxt *authctxt)
 461 {
 462         struct pam_ctxt *ctxt;
 463         int socks[2];
 464
 465         /* Refuse to start if we don't have PAM enabled */
 466         if (!options.use_pam)
 467                 return NULL;
 468
 469         /* Initialize PAM */
 470         if (sshpam_init(authctxt->user) == -1) {
 471                 error("PAM: initialization failed");
 472                 return (NULL);
 473         }
 474
 475         ctxt = xmalloc(sizeof *ctxt);
 476         memset(ctxt, 0, sizeof(*ctxt));
 477
 478         /* Start the authentication thread */
 479         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 480                 error("PAM: failed create sockets: %s", strerror(errno));
 481                 xfree(ctxt);
 482                 return (NULL);
 483         }
 484         ctxt->pam_psock = socks[0];
 485         ctxt->pam_csock = socks[1];
 486         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 487                 error("PAM: failed to start authentication thread: %s",
 488                     strerror(errno));
 489                 close(socks[0]);
 490                 close(socks[1]);
 491                 xfree(ctxt);
 492                 return (NULL);
 493         }
 494         cleanup_ctxt = ctxt;
 495         return (ctxt);
 496 }
 497
 498 static int
 499 sshpam_query(void *ctx, char **name, char **info,
 500     u_int *num, char ***prompts, u_int **echo_on)
 501 {
 502         Buffer buffer;
 503         struct pam_ctxt *ctxt = ctx;
 504         size_t plen;
 505         u_char type;
 506         char *msg;
 507         size_t len;
 508
 509         buffer_init(&buffer);
 510         *name = xstrdup("");
 511         *info = xstrdup("");
 512         *prompts = xmalloc(sizeof(char *));
 513         **prompts = NULL;
 514         plen = 0;
 515         *echo_on = xmalloc(sizeof(u_int));
 516         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 517                 type = buffer_get_char(&buffer);
 518                 msg = buffer_get_string(&buffer, NULL);
 519                 switch (type) {
 520                 case PAM_PROMPT_ECHO_ON:
 521                 case PAM_PROMPT_ECHO_OFF:
 522                         *num = 1;
 523                         len = plen + strlen(msg) + 1;
 524                         **prompts = xrealloc(**prompts, len);
 525                         plen += snprintf(**prompts + plen, len, "%s", msg);
 526                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 527                         xfree(msg);
 528                         return (0);
 529                 case PAM_ERROR_MSG:
 530                 case PAM_TEXT_INFO:
 531                         /* accumulate messages */
 532                         len = plen + strlen(msg) + 2;
 533                         **prompts = xrealloc(**prompts, len);
 534                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 535                         xfree(msg);
 536                         break;
 537                 case PAM_SUCCESS:
 538                 case PAM_AUTH_ERR:
 539                         if (**prompts != NULL) {
 540                                 /* drain any accumulated messages */
 541                                 debug("PAM: %s", **prompts);
 542                                 buffer_append(&loginmsg, **prompts,
 543                                     strlen(**prompts));
 544                                 xfree(**prompts);
 545                                 **prompts = NULL;
 546                         }
 547                         if (type == PAM_SUCCESS) {
 548                                 import_environments(&buffer);
 549                                 *num = 0;
 550                                 **echo_on = 0;
 551                                 ctxt->pam_done = 1;
 552                                 xfree(msg);
 553                                 return (0);
 554                         }
 555                         error("PAM: %s", msg);
 556                         /* FALLTHROUGH */
 557                 default:
 558                         *num = 0;
 559                         **echo_on = 0;
 560                         xfree(msg);
 561                         ctxt->pam_done = -1;
 562                         return (-1);
 563                 }
 564         }
 565         return (-1);
 566 }
 567
 568 /* XXX - see also comment in auth-chall.c:verify_response */
 569 static int
 570 sshpam_respond(void *ctx, u_int num, char **resp)
 571 {
 572         Buffer buffer;
 573         struct pam_ctxt *ctxt = ctx;
 574
 575         debug2("PAM: %s", __func__);
 576         switch (ctxt->pam_done) {
 577         case 1:
 578                 sshpam_authenticated = 1;
 579                 return (0);
 580         case 0:
 581                 break;
 582         default:
 583                 return (-1);
 584         }
 585         if (num != 1) {
 586                 error("PAM: expected one response, got %u", num);
 587                 return (-1);
 588         }
 589         buffer_init(&buffer);
 590         buffer_put_cstring(&buffer, *resp);
 591         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 592                 buffer_free(&buffer);
 593                 return (-1);
 594         }
 595         buffer_free(&buffer);
 596         return (1);
 597 }
 598
 599 static void
 600 sshpam_free_ctx(void *ctxtp)
 601 {
 602         struct pam_ctxt *ctxt = ctxtp;
 603
 604         sshpam_thread_cleanup();
 605         xfree(ctxt);
 606         /*
 607          * We don't call sshpam_cleanup() here because we may need the PAM
 608          * handle at a later stage, e.g. when setting up a session.  It's
 609          * still on the cleanup list, so pam_end() *will* be called before
 610          * the server process terminates.
 611          */
 612 }
 613
 614 KbdintDevice sshpam_device = {
 615         "pam",
 616         sshpam_init_ctx,
 617         sshpam_query,
 618         sshpam_respond,
 619         sshpam_free_ctx
 620 };
 621
 622 KbdintDevice mm_sshpam_device = {
 623         "pam",
 624         mm_sshpam_init_ctx,
 625         mm_sshpam_query,
 626         mm_sshpam_respond,
 627         mm_sshpam_free_ctx
 628 };
 629
 630 /*
 631  * This replaces auth-pam.c
 632  */
 633 void
 634 start_pam(const char *user)
 635 {
 636         if (!options.use_pam)
 637                 fatal("PAM: initialisation requested when UsePAM=no");
 638
 639         if (sshpam_init(user) == -1)
 640                 fatal("PAM: initialisation failed");
 641 }
 642
 643 void
 644 finish_pam(void)
 645 {
 646         sshpam_cleanup();
 647 }
 648
 649 u_int
 650 do_pam_account(void)
 651 {
 652         if (sshpam_account_status != -1)
 653                 return (sshpam_account_status);
 654
 655         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 656         debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);
 657
 658         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
 659                 sshpam_account_status = 0;
 660                 return (sshpam_account_status);
 661         }
 662
 663         if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
 664                 pam_password_change_required(1);
 665
 666         sshpam_account_status = 1;
 667         return (sshpam_account_status);
 668 }
 669
 670 void
 671 do_pam_set_tty(const char *tty)
 672 {
 673         if (tty != NULL) {
 674                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 675                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 676                 if (sshpam_err != PAM_SUCCESS)
 677                         fatal("PAM: failed to set PAM_TTY: %s",
 678                             pam_strerror(sshpam_handle, sshpam_err));
 679         }
 680 }
 681
 682 void
 683 do_pam_setcred(int init)
 684 {
 685         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 686             (const void *)&null_conv);
 687         if (sshpam_err != PAM_SUCCESS)
 688                 fatal("PAM: failed to set PAM_CONV: %s",
 689                     pam_strerror(sshpam_handle, sshpam_err));
 690         if (init) {
 691                 debug("PAM: establishing credentials");
 692                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 693         } else {
 694                 debug("PAM: reinitializing credentials");
 695                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 696         }
 697         if (sshpam_err == PAM_SUCCESS) {
 698                 sshpam_cred_established = 1;
 699                 return;
 700         }
 701         if (sshpam_authenticated)
 702                 fatal("PAM: pam_setcred(): %s",
 703                     pam_strerror(sshpam_handle, sshpam_err));
 704         else
 705                 debug("PAM: pam_setcred(): %s",
 706                     pam_strerror(sshpam_handle, sshpam_err));
 707 }
 708
 709 int
 710 is_pam_password_change_required(void)
 711 {
 712         return (sshpam_new_authtok_reqd);
 713 }
 714
 715 static int
 716 pam_tty_conv(int n, const struct pam_message **msg,
 717     struct pam_response **resp, void *data)
 718 {
 719         char input[PAM_MAX_MSG_SIZE];
 720         struct pam_response *reply;
 721         int i;
 722
 723         *resp = NULL;
 724
 725         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
 726                 return (PAM_CONV_ERR);
 727
 728         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 729                 return (PAM_CONV_ERR);
 730         memset(reply, 0, n * sizeof(*reply));
 731
 732         for (i = 0; i < n; ++i) {
 733                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 734                 case PAM_PROMPT_ECHO_OFF:
 735                         reply[i].resp =
 736                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 737                             RP_ALLOW_STDIN);
 738                         reply[i].resp_retcode = PAM_SUCCESS;
 739                         break;
 740                 case PAM_PROMPT_ECHO_ON:
 741                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 742                         fgets(input, sizeof input, stdin);
 743                         reply[i].resp = xstrdup(input);
 744                         reply[i].resp_retcode = PAM_SUCCESS;
 745                         break;
 746                 case PAM_ERROR_MSG:
 747                 case PAM_TEXT_INFO:
 748                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 749                         reply[i].resp_retcode = PAM_SUCCESS;
 750                         break;
 751                 default:
 752                         goto fail;
 753                 }
 754         }
 755         *resp = reply;
 756         return (PAM_SUCCESS);
 757
 758  fail:
 759         for(i = 0; i < n; i++) {
 760                 if (reply[i].resp != NULL)
 761                         xfree(reply[i].resp);
 762         }
 763         xfree(reply);
 764         return (PAM_CONV_ERR);
 765 }
 766
 767 static struct pam_conv tty_conv = { pam_tty_conv, NULL };
 768
 769 /*
 770  * XXX this should be done in the authentication phase, but ssh1 doesn't
 771  * support that
 772  */
 773 void
 774 do_pam_chauthtok(void)
 775 {
 776         if (use_privsep)
 777                 fatal("Password expired (unable to change with privsep)");
 778         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 779             (const void *)&tty_conv);
 780         if (sshpam_err != PAM_SUCCESS)
 781                 fatal("PAM: failed to set PAM_CONV: %s",
 782                     pam_strerror(sshpam_handle, sshpam_err));
 783         debug("PAM: changing password");
 784         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 785         if (sshpam_err != PAM_SUCCESS)
 786                 fatal("PAM: pam_chauthtok(): %s",
 787                     pam_strerror(sshpam_handle, sshpam_err));
 788 }
 789
 790 void
 791 do_pam_session(void)
 792 {
 793         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 794             (const void *)&tty_conv);
 795         if (sshpam_err != PAM_SUCCESS)
 796                 fatal("PAM: failed to set PAM_CONV: %s",
 797                     pam_strerror(sshpam_handle, sshpam_err));
 798         sshpam_err = pam_open_session(sshpam_handle, 0);
 799         if (sshpam_err != PAM_SUCCESS)
 800                 fatal("PAM: pam_open_session(): %s",
 801                     pam_strerror(sshpam_handle, sshpam_err));
 802         sshpam_session_open = 1;
 803 }
 804
 805 /*
 806  * Set a PAM environment string. We need to do this so that the session
 807  * modules can handle things like Kerberos/GSI credentials that appear
 808  * during the ssh authentication process.
 809  */
 810 int
 811 do_pam_putenv(char *name, char *value)
 812 {
 813         int ret = 1;
 814 #ifdef HAVE_PAM_PUTENV
 815         char *compound;
 816         size_t len;
 817
 818         len = strlen(name) + strlen(value) + 2;
 819         compound = xmalloc(len);
 820
 821         snprintf(compound, len, "%s=%s", name, value);
 822         ret = pam_putenv(sshpam_handle, compound);
 823         xfree(compound);
 824 #endif
 825
 826         return (ret);
 827 }
 828
 829 void
 830 print_pam_messages(void)
 831 {
 832         /* XXX */
 833 }
 834
 835 char **
 836 fetch_pam_child_environment(void)
 837 {
 838         return sshpam_env;
 839 }
 840
 841 char **
 842 fetch_pam_environment(void)
 843 {
 844         return (pam_getenvlist(sshpam_handle));
 845 }
 846
 847 void
 848 free_pam_environment(char **env)
 849 {
 850         char **envp;
 851
 852         if (env == NULL)
 853                 return;
 854
 855         for (envp = env; *envp; envp++)
 856                 xfree(*envp);
 857         xfree(env);
 858 }
 859
 860 #endif /* USE_PAM */