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 #if defined(HAVE_SECURITY_PAM_APPL_H)
  38 #include <security/pam_appl.h>
  39 #elif defined (HAVE_PAM_PAM_APPL_H)
  40 #include <pam/pam_appl.h>
  41 #endif
  42
  43 #include "auth.h"
  44 #include "auth-pam.h"
  45 #include "buffer.h"
  46 #include "bufaux.h"
  47 #include "canohost.h"
  48 #include "log.h"
  49 #include "monitor_wrap.h"
  50 #include "msg.h"
  51 #include "packet.h"
  52 #include "readpass.h"
  53 #include "servconf.h"
  54 #include "ssh2.h"
  55 #include "xmalloc.h"
  56 #include "auth-options.h"
  57
  58 extern ServerOptions options;
  59 extern Buffer loginmsg;
  60 extern int compat20;
  61
  62 #define __unused
  63
  64 #ifdef USE_POSIX_THREADS
  65 #include <pthread.h>
  66 /*
  67  * Avoid namespace clash when *not* using pthreads for systems *with*
  68  * pthreads, which unconditionally define pthread_t via sys/types.h
  69  * (e.g. Linux)
  70  */
  71 typedef pthread_t sp_pthread_t;
  72 #else
  73 /*
  74  * Simulate threads with processes.
  75  */
  76 typedef pid_t sp_pthread_t;
  77
  78 static void
  79 pthread_exit(void *value __unused)
  80 {
  81         _exit(0);
  82 }
  83
  84 static int
  85 pthread_create(sp_pthread_t *thread, const void *attr __unused,
  86     void *(*thread_start)(void *), void *arg)
  87 {
  88         pid_t pid;
  89
  90         switch ((pid = fork())) {
  91         case -1:
  92                 error("fork(): %s", strerror(errno));
  93                 return (-1);
  94         case 0:
  95                 thread_start(arg);
  96                 _exit(1);
  97         default:
  98                 *thread = pid;
  99                 return (0);
 100         }
 101 }
 102
 103 static int
 104 pthread_cancel(sp_pthread_t thread)
 105 {
 106         return (kill(thread, SIGTERM));
 107 }
 108
 109 static int
 110 pthread_join(sp_pthread_t thread, void **value __unused)
 111 {
 112         int status;
 113
 114         waitpid(thread, &status, 0);
 115         return (status);
 116 }
 117 #endif
 118
 119
 120 static pam_handle_t *sshpam_handle = NULL;
 121 static int sshpam_err = 0;
 122 static int sshpam_authenticated = 0;
 123 static int sshpam_new_authtok_reqd = 0;
 124 static int sshpam_session_open = 0;
 125 static int sshpam_cred_established = 0;
 126 static int sshpam_account_status = -1;
 127 static char **sshpam_env = NULL;
 128
 129 struct pam_ctxt {
 130         sp_pthread_t     pam_thread;
 131         int              pam_psock;
 132         int              pam_csock;
 133         int              pam_done;
 134 };
 135
 136 static void sshpam_free_ctx(void *);
 137 static struct pam_ctxt *cleanup_ctxt;
 138
 139 /* Some PAM implementations don't implement this */
 140 #ifndef HAVE_PAM_GETENVLIST
 141 static char **
 142 pam_getenvlist(pam_handle_t *pamh)
 143 {
 144         /*
 145          * XXX - If necessary, we can still support envrionment passing
 146          * for platforms without pam_getenvlist by searching for known
 147          * env vars (e.g. KRB5CCNAME) from the PAM environment.
 148          */
 149          return NULL;
 150 }
 151 #endif
 152
 153 void
 154 pam_password_change_required(int reqd)
 155 {
 156         sshpam_new_authtok_reqd = reqd;
 157         if (reqd) {
 158                 no_port_forwarding_flag |= 2;
 159                 no_agent_forwarding_flag |= 2;
 160                 no_x11_forwarding_flag |= 2;
 161         } else {
 162                 no_port_forwarding_flag &= ~2;
 163                 no_agent_forwarding_flag &= ~2;
 164                 no_x11_forwarding_flag &= ~2;
 165
 166         }
 167 }
 168 /* Import regular and PAM environment from subprocess */
 169 static void
 170 import_environments(Buffer *b)
 171 {
 172         char *env;
 173         u_int i, num_env;
 174         int err;
 175
 176         /* Import variables set by do_pam_account */
 177         sshpam_account_status = buffer_get_int(b);
 178         pam_password_change_required(buffer_get_int(b));
 179
 180         /* Import environment from subprocess */
 181         num_env = buffer_get_int(b);
 182         sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
 183         debug3("PAM: num env strings %d", num_env);
 184         for(i = 0; i < num_env; i++)
 185                 sshpam_env[i] = buffer_get_string(b, NULL);
 186
 187         sshpam_env[num_env] = NULL;
 188
 189         /* Import PAM environment from subprocess */
 190         num_env = buffer_get_int(b);
 191         debug("PAM: num PAM env strings %d", num_env);
 192         for(i = 0; i < num_env; i++) {
 193                 env = buffer_get_string(b, NULL);
 194
 195 #ifdef HAVE_PAM_PUTENV
 196                 /* Errors are not fatal here */
 197                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 198                         error("PAM: pam_putenv: %s",
 199                             pam_strerror(sshpam_handle, sshpam_err));
 200                 }
 201 #endif
 202         }
 203 }
 204
 205 /*
 206  * Conversation function for authentication thread.
 207  */
 208 static int
 209 sshpam_thread_conv(int n, const struct pam_message **msg,
 210     struct pam_response **resp, void *data)
 211 {
 212         Buffer buffer;
 213         struct pam_ctxt *ctxt;
 214         struct pam_response *reply;
 215         int i;
 216
 217         *resp = NULL;
 218
 219         ctxt = data;
 220         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 221                 return (PAM_CONV_ERR);
 222
 223         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 224                 return (PAM_CONV_ERR);
 225         memset(reply, 0, n * sizeof(*reply));
 226
 227         buffer_init(&buffer);
 228         for (i = 0; i < n; ++i) {
 229                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 230                 case PAM_PROMPT_ECHO_OFF:
 231                         buffer_put_cstring(&buffer,
 232                             PAM_MSG_MEMBER(msg, i, msg));
 233                         if (ssh_msg_send(ctxt->pam_csock,
 234                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 235                                 goto fail;
 236                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 237                                 goto fail;
 238                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 239                                 goto fail;
 240                         reply[i].resp = buffer_get_string(&buffer, NULL);
 241                         break;
 242                 case PAM_PROMPT_ECHO_ON:
 243                         buffer_put_cstring(&buffer,
 244                             PAM_MSG_MEMBER(msg, i, msg));
 245                         if (ssh_msg_send(ctxt->pam_csock,
 246                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 247                                 goto fail;
 248                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 249                                 goto fail;
 250                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 251                                 goto fail;
 252                         reply[i].resp = buffer_get_string(&buffer, NULL);
 253                         break;
 254                 case PAM_ERROR_MSG:
 255                         buffer_put_cstring(&buffer,
 256                             PAM_MSG_MEMBER(msg, i, msg));
 257                         if (ssh_msg_send(ctxt->pam_csock,
 258                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 259                                 goto fail;
 260                         break;
 261                 case PAM_TEXT_INFO:
 262                         buffer_put_cstring(&buffer,
 263                             PAM_MSG_MEMBER(msg, i, msg));
 264                         if (ssh_msg_send(ctxt->pam_csock,
 265                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 266                                 goto fail;
 267                         break;
 268                 default:
 269                         goto fail;
 270                 }
 271                 buffer_clear(&buffer);
 272         }
 273         buffer_free(&buffer);
 274         *resp = reply;
 275         return (PAM_SUCCESS);
 276
 277  fail:
 278         for(i = 0; i < n; i++) {
 279                 if (reply[i].resp != NULL)
 280                         xfree(reply[i].resp);
 281         }
 282         xfree(reply);
 283         buffer_free(&buffer);
 284         return (PAM_CONV_ERR);
 285 }
 286
 287 /*
 288  * Authentication thread.
 289  */
 290 static void *
 291 sshpam_thread(void *ctxtp)
 292 {
 293         struct pam_ctxt *ctxt = ctxtp;
 294         Buffer buffer;
 295         struct pam_conv sshpam_conv;
 296 #ifndef USE_POSIX_THREADS
 297         extern char **environ;
 298         char **env_from_pam;
 299         u_int i;
 300         const char *pam_user;
 301
 302         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 303         setproctitle("%s [pam]", pam_user);
 304         environ[0] = NULL;
 305 #endif
 306
 307         sshpam_conv.conv = sshpam_thread_conv;
 308         sshpam_conv.appdata_ptr = ctxt;
 309
 310         buffer_init(&buffer);
 311         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 312             (const void *)&sshpam_conv);
 313         if (sshpam_err != PAM_SUCCESS)
 314                 goto auth_fail;
 315         sshpam_err = pam_authenticate(sshpam_handle, 0);
 316         if (sshpam_err != PAM_SUCCESS)
 317                 goto auth_fail;
 318
 319         if (compat20) {
 320                 if (!do_pam_account())
 321                         goto auth_fail;
 322                 if (sshpam_new_authtok_reqd) {
 323                         sshpam_err = pam_chauthtok(sshpam_handle,
 324                             PAM_CHANGE_EXPIRED_AUTHTOK);
 325                         if (sshpam_err != PAM_SUCCESS)
 326                                 goto auth_fail;
 327                         pam_password_change_required(0);
 328                 }
 329         }
 330
 331         buffer_put_cstring(&buffer, "OK");
 332
 333 #ifndef USE_POSIX_THREADS
 334         /* Export variables set by do_pam_account */
 335         buffer_put_int(&buffer, sshpam_account_status);
 336         buffer_put_int(&buffer, sshpam_new_authtok_reqd);
 337
 338         /* Export any environment strings set in child */
 339         for(i = 0; environ[i] != NULL; i++)
 340                 ; /* Count */
 341         buffer_put_int(&buffer, i);
 342         for(i = 0; environ[i] != NULL; i++)
 343                 buffer_put_cstring(&buffer, environ[i]);
 344
 345         /* Export any environment strings set by PAM in child */
 346         env_from_pam = pam_getenvlist(sshpam_handle);
 347         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 348                 ; /* Count */
 349         buffer_put_int(&buffer, i);
 350         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 351                 buffer_put_cstring(&buffer, env_from_pam[i]);
 352 #endif /* USE_POSIX_THREADS */
 353
 354         /* XXX - can't do much about an error here */
 355         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 356         buffer_free(&buffer);
 357         pthread_exit(NULL);
 358
 359  auth_fail:
 360         buffer_put_cstring(&buffer,
 361             pam_strerror(sshpam_handle, sshpam_err));
 362         /* XXX - can't do much about an error here */
 363         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 364         buffer_free(&buffer);
 365         pthread_exit(NULL);
 366
 367         return (NULL); /* Avoid warning for non-pthread case */
 368 }
 369
 370 void
 371 sshpam_thread_cleanup(void)
 372 {
 373         struct pam_ctxt *ctxt = cleanup_ctxt;
 374
 375         if (ctxt != NULL && ctxt->pam_thread != 0) {
 376                 pthread_cancel(ctxt->pam_thread);
 377                 pthread_join(ctxt->pam_thread, NULL);
 378                 close(ctxt->pam_psock);
 379                 close(ctxt->pam_csock);
 380                 memset(ctxt, 0, sizeof(*ctxt));
 381                 cleanup_ctxt = NULL;
 382         }
 383 }
 384
 385 static int
 386 sshpam_null_conv(int n, const struct pam_message **msg,
 387     struct pam_response **resp, void *data)
 388 {
 389         return (PAM_CONV_ERR);
 390 }
 391
 392 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 393
 394 void
 395 sshpam_cleanup(void)
 396 {
 397         debug("PAM: cleanup");
 398         if (sshpam_handle == NULL)
 399                 return;
 400         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 401         if (sshpam_cred_established) {
 402                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 403                 sshpam_cred_established = 0;
 404         }
 405         if (sshpam_session_open) {
 406                 pam_close_session(sshpam_handle, PAM_SILENT);
 407                 sshpam_session_open = 0;
 408         }
 409         sshpam_authenticated = sshpam_new_authtok_reqd = 0;
 410         pam_end(sshpam_handle, sshpam_err);
 411         sshpam_handle = NULL;
 412 }
 413
 414 static int
 415 sshpam_init(const char *user)
 416 {
 417         extern u_int utmp_len;
 418         extern char *__progname;
 419         const char *pam_rhost, *pam_user;
 420
 421         if (sshpam_handle != NULL) {
 422                 /* We already have a PAM context; check if the user matches */
 423                 sshpam_err = pam_get_item(sshpam_handle,
 424                     PAM_USER, (const void **)&pam_user);
 425                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 426                         return (0);
 427                 pam_end(sshpam_handle, sshpam_err);
 428                 sshpam_handle = NULL;
 429         }
 430         debug("PAM: initializing for \"%s\"", user);
 431         sshpam_err =
 432             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 433         if (sshpam_err != PAM_SUCCESS) {
 434                 pam_end(sshpam_handle, sshpam_err);
 435                 sshpam_handle = NULL;
 436                 return (-1);
 437         }
 438         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 439         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 440         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 441         if (sshpam_err != PAM_SUCCESS) {
 442                 pam_end(sshpam_handle, sshpam_err);
 443                 sshpam_handle = NULL;
 444                 return (-1);
 445         }
 446 #ifdef PAM_TTY_KLUDGE
 447         /*
 448          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 449          * sshd doesn't set the tty until too late in the auth process and
 450          * may not even set one (for tty-less connections)
 451          */
 452         debug("PAM: setting PAM_TTY to \"ssh\"");
 453         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 454         if (sshpam_err != PAM_SUCCESS) {
 455                 pam_end(sshpam_handle, sshpam_err);
 456                 sshpam_handle = NULL;
 457                 return (-1);
 458         }
 459 #endif
 460         return (0);
 461 }
 462
 463 static void *
 464 sshpam_init_ctx(Authctxt *authctxt)
 465 {
 466         struct pam_ctxt *ctxt;
 467         int socks[2];
 468
 469         /* Refuse to start if we don't have PAM enabled */
 470         if (!options.use_pam)
 471                 return NULL;
 472
 473         /* Initialize PAM */
 474         if (sshpam_init(authctxt->user) == -1) {
 475                 error("PAM: initialization failed");
 476                 return (NULL);
 477         }
 478
 479         ctxt = xmalloc(sizeof *ctxt);
 480         memset(ctxt, 0, sizeof(*ctxt));
 481
 482         /* Start the authentication thread */
 483         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 484                 error("PAM: failed create sockets: %s", strerror(errno));
 485                 xfree(ctxt);
 486                 return (NULL);
 487         }
 488         ctxt->pam_psock = socks[0];
 489         ctxt->pam_csock = socks[1];
 490         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 491                 error("PAM: failed to start authentication thread: %s",
 492                     strerror(errno));
 493                 close(socks[0]);
 494                 close(socks[1]);
 495                 xfree(ctxt);
 496                 return (NULL);
 497         }
 498         cleanup_ctxt = ctxt;
 499         return (ctxt);
 500 }
 501
 502 static int
 503 sshpam_query(void *ctx, char **name, char **info,
 504     u_int *num, char ***prompts, u_int **echo_on)
 505 {
 506         Buffer buffer;
 507         struct pam_ctxt *ctxt = ctx;
 508         size_t plen;
 509         u_char type;
 510         char *msg;
 511         size_t len;
 512
 513         buffer_init(&buffer);
 514         *name = xstrdup("");
 515         *info = xstrdup("");
 516         *prompts = xmalloc(sizeof(char *));
 517         **prompts = NULL;
 518         plen = 0;
 519         *echo_on = xmalloc(sizeof(u_int));
 520         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 521                 type = buffer_get_char(&buffer);
 522                 msg = buffer_get_string(&buffer, NULL);
 523                 switch (type) {
 524                 case PAM_PROMPT_ECHO_ON:
 525                 case PAM_PROMPT_ECHO_OFF:
 526                         *num = 1;
 527                         len = plen + strlen(msg) + 1;
 528                         **prompts = xrealloc(**prompts, len);
 529                         plen += snprintf(**prompts + plen, len, "%s", msg);
 530                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 531                         xfree(msg);
 532                         return (0);
 533                 case PAM_ERROR_MSG:
 534                 case PAM_TEXT_INFO:
 535                         /* accumulate messages */
 536                         len = plen + strlen(msg) + 2;
 537                         **prompts = xrealloc(**prompts, len);
 538                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 539                         xfree(msg);
 540                         break;
 541                 case PAM_SUCCESS:
 542                 case PAM_AUTH_ERR:
 543                         if (**prompts != NULL) {
 544                                 /* drain any accumulated messages */
 545                                 debug("PAM: %s", **prompts);
 546                                 buffer_append(&loginmsg, **prompts,
 547                                     strlen(**prompts));
 548                                 xfree(**prompts);
 549                                 **prompts = NULL;
 550                         }
 551                         if (type == PAM_SUCCESS) {
 552                                 import_environments(&buffer);
 553                                 *num = 0;
 554                                 **echo_on = 0;
 555                                 ctxt->pam_done = 1;
 556                                 xfree(msg);
 557                                 return (0);
 558                         }
 559                         error("PAM: %s", msg);
 560                         /* FALLTHROUGH */
 561                 default:
 562                         *num = 0;
 563                         **echo_on = 0;
 564                         xfree(msg);
 565                         ctxt->pam_done = -1;
 566                         return (-1);
 567                 }
 568         }
 569         return (-1);
 570 }
 571
 572 /* XXX - see also comment in auth-chall.c:verify_response */
 573 static int
 574 sshpam_respond(void *ctx, u_int num, char **resp)
 575 {
 576         Buffer buffer;
 577         struct pam_ctxt *ctxt = ctx;
 578
 579         debug2("PAM: %s", __func__);
 580         switch (ctxt->pam_done) {
 581         case 1:
 582                 sshpam_authenticated = 1;
 583                 return (0);
 584         case 0:
 585                 break;
 586         default:
 587                 return (-1);
 588         }
 589         if (num != 1) {
 590                 error("PAM: expected one response, got %u", num);
 591                 return (-1);
 592         }
 593         buffer_init(&buffer);
 594         buffer_put_cstring(&buffer, *resp);
 595         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 596                 buffer_free(&buffer);
 597                 return (-1);
 598         }
 599         buffer_free(&buffer);
 600         return (1);
 601 }
 602
 603 static void
 604 sshpam_free_ctx(void *ctxtp)
 605 {
 606         struct pam_ctxt *ctxt = ctxtp;
 607
 608         sshpam_thread_cleanup();
 609         xfree(ctxt);
 610         /*
 611          * We don't call sshpam_cleanup() here because we may need the PAM
 612          * handle at a later stage, e.g. when setting up a session.  It's
 613          * still on the cleanup list, so pam_end() *will* be called before
 614          * the server process terminates.
 615          */
 616 }
 617
 618 KbdintDevice sshpam_device = {
 619         "pam",
 620         sshpam_init_ctx,
 621         sshpam_query,
 622         sshpam_respond,
 623         sshpam_free_ctx
 624 };
 625
 626 KbdintDevice mm_sshpam_device = {
 627         "pam",
 628         mm_sshpam_init_ctx,
 629         mm_sshpam_query,
 630         mm_sshpam_respond,
 631         mm_sshpam_free_ctx
 632 };
 633
 634 /*
 635  * This replaces auth-pam.c
 636  */
 637 void
 638 start_pam(const char *user)
 639 {
 640         if (!options.use_pam)
 641                 fatal("PAM: initialisation requested when UsePAM=no");
 642
 643         if (sshpam_init(user) == -1)
 644                 fatal("PAM: initialisation failed");
 645 }
 646
 647 void
 648 finish_pam(void)
 649 {
 650         sshpam_cleanup();
 651 }
 652
 653 u_int
 654 do_pam_account(void)
 655 {
 656         if (sshpam_account_status != -1)
 657                 return (sshpam_account_status);
 658
 659         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 660         debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);
 661
 662         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
 663                 sshpam_account_status = 0;
 664                 return (sshpam_account_status);
 665         }
 666
 667         if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
 668                 pam_password_change_required(1);
 669
 670         sshpam_account_status = 1;
 671         return (sshpam_account_status);
 672 }
 673
 674 void
 675 do_pam_set_tty(const char *tty)
 676 {
 677         if (tty != NULL) {
 678                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 679                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 680                 if (sshpam_err != PAM_SUCCESS)
 681                         fatal("PAM: failed to set PAM_TTY: %s",
 682                             pam_strerror(sshpam_handle, sshpam_err));
 683         }
 684 }
 685
 686 void
 687 do_pam_setcred(int init)
 688 {
 689         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 690             (const void *)&null_conv);
 691         if (sshpam_err != PAM_SUCCESS)
 692                 fatal("PAM: failed to set PAM_CONV: %s",
 693                     pam_strerror(sshpam_handle, sshpam_err));
 694         if (init) {
 695                 debug("PAM: establishing credentials");
 696                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 697         } else {
 698                 debug("PAM: reinitializing credentials");
 699                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 700         }
 701         if (sshpam_err == PAM_SUCCESS) {
 702                 sshpam_cred_established = 1;
 703                 return;
 704         }
 705         if (sshpam_authenticated)
 706                 fatal("PAM: pam_setcred(): %s",
 707                     pam_strerror(sshpam_handle, sshpam_err));
 708         else
 709                 debug("PAM: pam_setcred(): %s",
 710                     pam_strerror(sshpam_handle, sshpam_err));
 711 }
 712
 713 int
 714 is_pam_password_change_required(void)
 715 {
 716         return (sshpam_new_authtok_reqd);
 717 }
 718
 719 static int
 720 pam_tty_conv(int n, const struct pam_message **msg,
 721     struct pam_response **resp, void *data)
 722 {
 723         char input[PAM_MAX_MSG_SIZE];
 724         struct pam_response *reply;
 725         int i;
 726
 727         *resp = NULL;
 728
 729         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
 730                 return (PAM_CONV_ERR);
 731
 732         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 733                 return (PAM_CONV_ERR);
 734         memset(reply, 0, n * sizeof(*reply));
 735
 736         for (i = 0; i < n; ++i) {
 737                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 738                 case PAM_PROMPT_ECHO_OFF:
 739                         reply[i].resp =
 740                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 741                             RP_ALLOW_STDIN);
 742                         reply[i].resp_retcode = PAM_SUCCESS;
 743                         break;
 744                 case PAM_PROMPT_ECHO_ON:
 745                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 746                         fgets(input, sizeof input, stdin);
 747                         reply[i].resp = xstrdup(input);
 748                         reply[i].resp_retcode = PAM_SUCCESS;
 749                         break;
 750                 case PAM_ERROR_MSG:
 751                 case PAM_TEXT_INFO:
 752                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 753                         reply[i].resp_retcode = PAM_SUCCESS;
 754                         break;
 755                 default:
 756                         goto fail;
 757                 }
 758         }
 759         *resp = reply;
 760         return (PAM_SUCCESS);
 761
 762  fail:
 763         for(i = 0; i < n; i++) {
 764                 if (reply[i].resp != NULL)
 765                         xfree(reply[i].resp);
 766         }
 767         xfree(reply);
 768         return (PAM_CONV_ERR);
 769 }
 770
 771 static struct pam_conv tty_conv = { pam_tty_conv, NULL };
 772
 773 /*
 774  * XXX this should be done in the authentication phase, but ssh1 doesn't
 775  * support that
 776  */
 777 void
 778 do_pam_chauthtok(void)
 779 {
 780         if (use_privsep)
 781                 fatal("Password expired (unable to change with privsep)");
 782         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 783             (const void *)&tty_conv);
 784         if (sshpam_err != PAM_SUCCESS)
 785                 fatal("PAM: failed to set PAM_CONV: %s",
 786                     pam_strerror(sshpam_handle, sshpam_err));
 787         debug("PAM: changing password");
 788         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 789         if (sshpam_err != PAM_SUCCESS)
 790                 fatal("PAM: pam_chauthtok(): %s",
 791                     pam_strerror(sshpam_handle, sshpam_err));
 792 }
 793
 794 void
 795 do_pam_session(void)
 796 {
 797         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 798             (const void *)&tty_conv);
 799         if (sshpam_err != PAM_SUCCESS)
 800                 fatal("PAM: failed to set PAM_CONV: %s",
 801                     pam_strerror(sshpam_handle, sshpam_err));
 802         sshpam_err = pam_open_session(sshpam_handle, 0);
 803         if (sshpam_err != PAM_SUCCESS)
 804                 fatal("PAM: pam_open_session(): %s",
 805                     pam_strerror(sshpam_handle, sshpam_err));
 806         sshpam_session_open = 1;
 807 }
 808
 809 /*
 810  * Set a PAM environment string. We need to do this so that the session
 811  * modules can handle things like Kerberos/GSI credentials that appear
 812  * during the ssh authentication process.
 813  */
 814 int
 815 do_pam_putenv(char *name, char *value)
 816 {
 817         int ret = 1;
 818 #ifdef HAVE_PAM_PUTENV
 819         char *compound;
 820         size_t len;
 821
 822         len = strlen(name) + strlen(value) + 2;
 823         compound = xmalloc(len);
 824
 825         snprintf(compound, len, "%s=%s", name, value);
 826         ret = pam_putenv(sshpam_handle, compound);
 827         xfree(compound);
 828 #endif
 829
 830         return (ret);
 831 }
 832
 833 void
 834 print_pam_messages(void)
 835 {
 836         /* XXX */
 837 }
 838
 839 char **
 840 fetch_pam_child_environment(void)
 841 {
 842         return sshpam_env;
 843 }
 844
 845 char **
 846 fetch_pam_environment(void)
 847 {
 848         return (pam_getenvlist(sshpam_handle));
 849 }
 850
 851 void
 852 free_pam_environment(char **env)
 853 {
 854         char **envp;
 855
 856         if (env == NULL)
 857                 return;
 858
 859         for (envp = env; *envp; envp++)
 860                 xfree(*envp);
 861         xfree(env);
 862 }
 863
 864 #endif /* USE_PAM */