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 #ifdef USE_POSIX_THREADS
  63 #include <pthread.h>
  64 /*
  65  * Avoid namespace clash when *not* using pthreads for systems *with*
  66  * pthreads, which unconditionally define pthread_t via sys/types.h
  67  * (e.g. Linux)
  68  */
  69 typedef pthread_t sp_pthread_t;
  70 #else
  71 typedef pid_t sp_pthread_t;
  72 #endif
  73
  74 struct pam_ctxt {
  75         sp_pthread_t     pam_thread;
  76         int              pam_psock;
  77         int              pam_csock;
  78         int              pam_done;
  79 };
  80
  81 static void sshpam_free_ctx(void *);
  82 static struct pam_ctxt *cleanup_ctxt;
  83
  84 #ifndef USE_POSIX_THREADS
  85 /*
  86  * Simulate threads with processes.
  87  */
  88
  89 static int sshpam_thread_status = -1;
  90 static mysig_t sshpam_oldsig;
  91
  92 static void
  93 sshpam_sigchld_handler(int sig)
  94 {
  95         if (cleanup_ctxt == NULL)
  96                 return; /* handler called after PAM cleanup, shouldn't happen */
  97         if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0) == -1)
  98                 return; /* couldn't wait for process */
  99         if (WIFSIGNALED(sshpam_thread_status) &&
 100             WTERMSIG(sshpam_thread_status) == SIGTERM)
 101                 return; /* terminated by pthread_cancel */
 102         if (!WIFEXITED(sshpam_thread_status))
 103                 fatal("PAM: authentication thread exited unexpectedly");
 104         if (WEXITSTATUS(sshpam_thread_status) != 0)
 105                 fatal("PAM: authentication thread exited uncleanly");
 106 }
 107
 108 static void
 109 pthread_exit(void *value __unused)
 110 {
 111         _exit(0);
 112 }
 113
 114 static int
 115 pthread_create(sp_pthread_t *thread, const void *attr __unused,
 116     void *(*thread_start)(void *), void *arg)
 117 {
 118         pid_t pid;
 119
 120         switch ((pid = fork())) {
 121         case -1:
 122                 error("fork(): %s", strerror(errno));
 123                 return (-1);
 124         case 0:
 125                 thread_start(arg);
 126                 _exit(1);
 127         default:
 128                 *thread = pid;
 129                 sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
 130                 return (0);
 131         }
 132 }
 133
 134 static int
 135 pthread_cancel(sp_pthread_t thread)
 136 {
 137         signal(SIGCHLD, sshpam_oldsig);
 138         return (kill(thread, SIGTERM));
 139 }
 140
 141 static int
 142 pthread_join(sp_pthread_t thread, void **value __unused)
 143 {
 144         int status;
 145
 146         if (sshpam_thread_status != -1)
 147                 return (sshpam_thread_status);
 148         signal(SIGCHLD, sshpam_oldsig);
 149         waitpid(thread, &status, 0);
 150         return (status);
 151 }
 152 #endif
 153
 154
 155 static pam_handle_t *sshpam_handle = NULL;
 156 static int sshpam_err = 0;
 157 static int sshpam_authenticated = 0;
 158 static int sshpam_session_open = 0;
 159 static int sshpam_cred_established = 0;
 160 static int sshpam_account_status = -1;
 161 static char **sshpam_env = NULL;
 162 static int *force_pwchange;
 163
 164 /* Some PAM implementations don't implement this */
 165 #ifndef HAVE_PAM_GETENVLIST
 166 static char **
 167 pam_getenvlist(pam_handle_t *pamh)
 168 {
 169         /*
 170          * XXX - If necessary, we can still support envrionment passing
 171          * for platforms without pam_getenvlist by searching for known
 172          * env vars (e.g. KRB5CCNAME) from the PAM environment.
 173          */
 174          return NULL;
 175 }
 176 #endif
 177
 178 void
 179 pam_password_change_required(int reqd)
 180 {
 181         debug3("%s %d", __func__, reqd);
 182         *force_pwchange = reqd;
 183         if (reqd) {
 184                 no_port_forwarding_flag |= 2;
 185                 no_agent_forwarding_flag |= 2;
 186                 no_x11_forwarding_flag |= 2;
 187         } else {
 188                 no_port_forwarding_flag &= ~2;
 189                 no_agent_forwarding_flag &= ~2;
 190                 no_x11_forwarding_flag &= ~2;
 191         }
 192 }
 193
 194 /* Import regular and PAM environment from subprocess */
 195 static void
 196 import_environments(Buffer *b)
 197 {
 198         char *env;
 199         u_int i, num_env;
 200         int err;
 201
 202         debug3("PAM: %s entering", __func__);
 203
 204 #ifndef USE_POSIX_THREADS
 205         /* Import variables set by do_pam_account */
 206         sshpam_account_status = buffer_get_int(b);
 207         pam_password_change_required(buffer_get_int(b));
 208
 209         /* Import environment from subprocess */
 210         num_env = buffer_get_int(b);
 211         sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
 212         debug3("PAM: num env strings %d", num_env);
 213         for(i = 0; i < num_env; i++)
 214                 sshpam_env[i] = buffer_get_string(b, NULL);
 215
 216         sshpam_env[num_env] = NULL;
 217
 218         /* Import PAM environment from subprocess */
 219         num_env = buffer_get_int(b);
 220         debug("PAM: num PAM env strings %d", num_env);
 221         for(i = 0; i < num_env; i++) {
 222                 env = buffer_get_string(b, NULL);
 223
 224 #ifdef HAVE_PAM_PUTENV
 225                 /* Errors are not fatal here */
 226                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 227                         error("PAM: pam_putenv: %s",
 228                             pam_strerror(sshpam_handle, sshpam_err));
 229                 }
 230 #endif
 231         }
 232 #endif
 233 }
 234
 235 /*
 236  * Conversation function for authentication thread.
 237  */
 238 static int
 239 sshpam_thread_conv(int n, const struct pam_message **msg,
 240     struct pam_response **resp, void *data)
 241 {
 242         Buffer buffer;
 243         struct pam_ctxt *ctxt;
 244         struct pam_response *reply;
 245         int i;
 246
 247         debug3("PAM: %s entering, %d messages", __func__, n);
 248         *resp = NULL;
 249
 250         ctxt = data;
 251         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 252                 return (PAM_CONV_ERR);
 253
 254         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 255                 return (PAM_CONV_ERR);
 256         memset(reply, 0, n * sizeof(*reply));
 257
 258         buffer_init(&buffer);
 259         for (i = 0; i < n; ++i) {
 260                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 261                 case PAM_PROMPT_ECHO_OFF:
 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                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 268                                 goto fail;
 269                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 270                                 goto fail;
 271                         reply[i].resp = buffer_get_string(&buffer, NULL);
 272                         break;
 273                 case PAM_PROMPT_ECHO_ON:
 274                         buffer_put_cstring(&buffer,
 275                             PAM_MSG_MEMBER(msg, i, msg));
 276                         if (ssh_msg_send(ctxt->pam_csock,
 277                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 278                                 goto fail;
 279                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 280                                 goto fail;
 281                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 282                                 goto fail;
 283                         reply[i].resp = buffer_get_string(&buffer, NULL);
 284                         break;
 285                 case PAM_ERROR_MSG:
 286                         buffer_put_cstring(&buffer,
 287                             PAM_MSG_MEMBER(msg, i, msg));
 288                         if (ssh_msg_send(ctxt->pam_csock,
 289                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 290                                 goto fail;
 291                         break;
 292                 case PAM_TEXT_INFO:
 293                         buffer_put_cstring(&buffer,
 294                             PAM_MSG_MEMBER(msg, i, msg));
 295                         if (ssh_msg_send(ctxt->pam_csock,
 296                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 297                                 goto fail;
 298                         break;
 299                 default:
 300                         goto fail;
 301                 }
 302                 buffer_clear(&buffer);
 303         }
 304         buffer_free(&buffer);
 305         *resp = reply;
 306         return (PAM_SUCCESS);
 307
 308  fail:
 309         for(i = 0; i < n; i++) {
 310                 if (reply[i].resp != NULL)
 311                         xfree(reply[i].resp);
 312         }
 313         xfree(reply);
 314         buffer_free(&buffer);
 315         return (PAM_CONV_ERR);
 316 }
 317
 318 /*
 319  * Authentication thread.
 320  */
 321 static void *
 322 sshpam_thread(void *ctxtp)
 323 {
 324         struct pam_ctxt *ctxt = ctxtp;
 325         Buffer buffer;
 326         struct pam_conv sshpam_conv;
 327 #ifndef USE_POSIX_THREADS
 328         extern char **environ;
 329         char **env_from_pam;
 330         u_int i;
 331         const char *pam_user;
 332
 333         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 334         setproctitle("%s [pam]", pam_user);
 335         environ[0] = NULL;
 336 #endif
 337
 338         sshpam_conv.conv = sshpam_thread_conv;
 339         sshpam_conv.appdata_ptr = ctxt;
 340
 341         buffer_init(&buffer);
 342         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 343             (const void *)&sshpam_conv);
 344         if (sshpam_err != PAM_SUCCESS)
 345                 goto auth_fail;
 346         sshpam_err = pam_authenticate(sshpam_handle, 0);
 347         if (sshpam_err != PAM_SUCCESS)
 348                 goto auth_fail;
 349
 350         if (compat20) {
 351                 if (!do_pam_account())
 352                         goto auth_fail;
 353                 if (*force_pwchange) {
 354                         sshpam_err = pam_chauthtok(sshpam_handle,
 355                             PAM_CHANGE_EXPIRED_AUTHTOK);
 356                         if (sshpam_err != PAM_SUCCESS)
 357                                 goto auth_fail;
 358                         pam_password_change_required(0);
 359                 }
 360         }
 361
 362         buffer_put_cstring(&buffer, "OK");
 363
 364 #ifndef USE_POSIX_THREADS
 365         /* Export variables set by do_pam_account */
 366         buffer_put_int(&buffer, sshpam_account_status);
 367         buffer_put_int(&buffer, *force_pwchange);
 368
 369         /* Export any environment strings set in child */
 370         for(i = 0; environ[i] != NULL; i++)
 371                 ; /* Count */
 372         buffer_put_int(&buffer, i);
 373         for(i = 0; environ[i] != NULL; i++)
 374                 buffer_put_cstring(&buffer, environ[i]);
 375
 376         /* Export any environment strings set by PAM in child */
 377         env_from_pam = pam_getenvlist(sshpam_handle);
 378         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 379                 ; /* Count */
 380         buffer_put_int(&buffer, i);
 381         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 382                 buffer_put_cstring(&buffer, env_from_pam[i]);
 383 #endif /* USE_POSIX_THREADS */
 384
 385         /* XXX - can't do much about an error here */
 386         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 387         buffer_free(&buffer);
 388         pthread_exit(NULL);
 389
 390  auth_fail:
 391         buffer_put_cstring(&buffer,
 392             pam_strerror(sshpam_handle, sshpam_err));
 393         /* XXX - can't do much about an error here */
 394         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 395         buffer_free(&buffer);
 396         pthread_exit(NULL);
 397
 398         return (NULL); /* Avoid warning for non-pthread case */
 399 }
 400
 401 void
 402 sshpam_thread_cleanup(void)
 403 {
 404         struct pam_ctxt *ctxt = cleanup_ctxt;
 405
 406         debug3("PAM: %s entering", __func__);
 407         if (ctxt != NULL && ctxt->pam_thread != 0) {
 408                 pthread_cancel(ctxt->pam_thread);
 409                 pthread_join(ctxt->pam_thread, NULL);
 410                 close(ctxt->pam_psock);
 411                 close(ctxt->pam_csock);
 412                 memset(ctxt, 0, sizeof(*ctxt));
 413                 cleanup_ctxt = NULL;
 414         }
 415 }
 416
 417 static int
 418 sshpam_null_conv(int n, const struct pam_message **msg,
 419     struct pam_response **resp, void *data)
 420 {
 421         debug3("PAM: %s entering, %d messages", __func__, n);
 422         return (PAM_CONV_ERR);
 423 }
 424
 425 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 426
 427 void
 428 sshpam_cleanup(void)
 429 {
 430         debug("PAM: cleanup");
 431         if (sshpam_handle == NULL)
 432                 return;
 433         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 434         if (sshpam_cred_established) {
 435                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 436                 sshpam_cred_established = 0;
 437         }
 438         if (sshpam_session_open) {
 439                 pam_close_session(sshpam_handle, PAM_SILENT);
 440                 sshpam_session_open = 0;
 441         }
 442         sshpam_authenticated = 0;
 443         pam_end(sshpam_handle, sshpam_err);
 444         sshpam_handle = NULL;
 445 }
 446
 447 static int
 448 sshpam_init(const char *user)
 449 {
 450         extern u_int utmp_len;
 451         extern char *__progname;
 452         const char *pam_rhost, *pam_user;
 453
 454         if (sshpam_handle != NULL) {
 455                 /* We already have a PAM context; check if the user matches */
 456                 sshpam_err = pam_get_item(sshpam_handle,
 457                     PAM_USER, (const void **)&pam_user);
 458                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 459                         return (0);
 460                 pam_end(sshpam_handle, sshpam_err);
 461                 sshpam_handle = NULL;
 462         }
 463         debug("PAM: initializing for \"%s\"", user);
 464         sshpam_err =
 465             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 466         if (sshpam_err != PAM_SUCCESS) {
 467                 pam_end(sshpam_handle, sshpam_err);
 468                 sshpam_handle = NULL;
 469                 return (-1);
 470         }
 471         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 472         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 473         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 474         if (sshpam_err != PAM_SUCCESS) {
 475                 pam_end(sshpam_handle, sshpam_err);
 476                 sshpam_handle = NULL;
 477                 return (-1);
 478         }
 479 #ifdef PAM_TTY_KLUDGE
 480         /*
 481          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 482          * sshd doesn't set the tty until too late in the auth process and
 483          * may not even set one (for tty-less connections)
 484          */
 485         debug("PAM: setting PAM_TTY to \"ssh\"");
 486         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 487         if (sshpam_err != PAM_SUCCESS) {
 488                 pam_end(sshpam_handle, sshpam_err);
 489                 sshpam_handle = NULL;
 490                 return (-1);
 491         }
 492 #endif
 493         return (0);
 494 }
 495
 496 static void *
 497 sshpam_init_ctx(Authctxt *authctxt)
 498 {
 499         struct pam_ctxt *ctxt;
 500         int socks[2];
 501
 502         debug3("PAM: %s entering", __func__);
 503         /* Refuse to start if we don't have PAM enabled */
 504         if (!options.use_pam)
 505                 return NULL;
 506
 507         /* Initialize PAM */
 508         if (sshpam_init(authctxt->user) == -1) {
 509                 error("PAM: initialization failed");
 510                 return (NULL);
 511         }
 512
 513         ctxt = xmalloc(sizeof *ctxt);
 514         memset(ctxt, 0, sizeof(*ctxt));
 515
 516         force_pwchange = &(authctxt->force_pwchange);
 517
 518         /* Start the authentication thread */
 519         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 520                 error("PAM: failed create sockets: %s", strerror(errno));
 521                 xfree(ctxt);
 522                 return (NULL);
 523         }
 524         ctxt->pam_psock = socks[0];
 525         ctxt->pam_csock = socks[1];
 526         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 527                 error("PAM: failed to start authentication thread: %s",
 528                     strerror(errno));
 529                 close(socks[0]);
 530                 close(socks[1]);
 531                 xfree(ctxt);
 532                 return (NULL);
 533         }
 534         cleanup_ctxt = ctxt;
 535         return (ctxt);
 536 }
 537
 538 static int
 539 sshpam_query(void *ctx, char **name, char **info,
 540     u_int *num, char ***prompts, u_int **echo_on)
 541 {
 542         Buffer buffer;
 543         struct pam_ctxt *ctxt = ctx;
 544         size_t plen;
 545         u_char type;
 546         char *msg;
 547         size_t len;
 548
 549         debug3("PAM: %s entering", __func__);
 550         buffer_init(&buffer);
 551         *name = xstrdup("");
 552         *info = xstrdup("");
 553         *prompts = xmalloc(sizeof(char *));
 554         **prompts = NULL;
 555         plen = 0;
 556         *echo_on = xmalloc(sizeof(u_int));
 557         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 558                 type = buffer_get_char(&buffer);
 559                 msg = buffer_get_string(&buffer, NULL);
 560                 switch (type) {
 561                 case PAM_PROMPT_ECHO_ON:
 562                 case PAM_PROMPT_ECHO_OFF:
 563                         *num = 1;
 564                         len = plen + strlen(msg) + 1;
 565                         **prompts = xrealloc(**prompts, len);
 566                         plen += snprintf(**prompts + plen, len, "%s", msg);
 567                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 568                         xfree(msg);
 569                         return (0);
 570                 case PAM_ERROR_MSG:
 571                 case PAM_TEXT_INFO:
 572                         /* accumulate messages */
 573                         len = plen + strlen(msg) + 2;
 574                         **prompts = xrealloc(**prompts, len);
 575                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 576                         xfree(msg);
 577                         break;
 578                 case PAM_SUCCESS:
 579                 case PAM_AUTH_ERR:
 580                         if (**prompts != NULL) {
 581                                 /* drain any accumulated messages */
 582                                 debug("PAM: %s", **prompts);
 583                                 buffer_append(&loginmsg, **prompts,
 584                                     strlen(**prompts));
 585                                 xfree(**prompts);
 586                                 **prompts = NULL;
 587                         }
 588                         if (type == PAM_SUCCESS) {
 589                                 import_environments(&buffer);
 590                                 *num = 0;
 591                                 **echo_on = 0;
 592                                 ctxt->pam_done = 1;
 593                                 xfree(msg);
 594                                 return (0);
 595                         }
 596                         error("PAM: %s", msg);
 597                         /* FALLTHROUGH */
 598                 default:
 599                         *num = 0;
 600                         **echo_on = 0;
 601                         xfree(msg);
 602                         ctxt->pam_done = -1;
 603                         return (-1);
 604                 }
 605         }
 606         return (-1);
 607 }
 608
 609 /* XXX - see also comment in auth-chall.c:verify_response */
 610 static int
 611 sshpam_respond(void *ctx, u_int num, char **resp)
 612 {
 613         Buffer buffer;
 614         struct pam_ctxt *ctxt = ctx;
 615
 616         debug2("PAM: %s entering, %d responses", __func__, num);
 617         switch (ctxt->pam_done) {
 618         case 1:
 619                 sshpam_authenticated = 1;
 620                 return (0);
 621         case 0:
 622                 break;
 623         default:
 624                 return (-1);
 625         }
 626         if (num != 1) {
 627                 error("PAM: expected one response, got %u", num);
 628                 return (-1);
 629         }
 630         buffer_init(&buffer);
 631         buffer_put_cstring(&buffer, *resp);
 632         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 633                 buffer_free(&buffer);
 634                 return (-1);
 635         }
 636         buffer_free(&buffer);
 637         return (1);
 638 }
 639
 640 static void
 641 sshpam_free_ctx(void *ctxtp)
 642 {
 643         struct pam_ctxt *ctxt = ctxtp;
 644
 645         debug3("PAM: %s entering", __func__);
 646         sshpam_thread_cleanup();
 647         xfree(ctxt);
 648         /*
 649          * We don't call sshpam_cleanup() here because we may need the PAM
 650          * handle at a later stage, e.g. when setting up a session.  It's
 651          * still on the cleanup list, so pam_end() *will* be called before
 652          * the server process terminates.
 653          */
 654 }
 655
 656 KbdintDevice sshpam_device = {
 657         "pam",
 658         sshpam_init_ctx,
 659         sshpam_query,
 660         sshpam_respond,
 661         sshpam_free_ctx
 662 };
 663
 664 KbdintDevice mm_sshpam_device = {
 665         "pam",
 666         mm_sshpam_init_ctx,
 667         mm_sshpam_query,
 668         mm_sshpam_respond,
 669         mm_sshpam_free_ctx
 670 };
 671
 672 /*
 673  * This replaces auth-pam.c
 674  */
 675 void
 676 start_pam(const char *user)
 677 {
 678         if (!options.use_pam)
 679                 fatal("PAM: initialisation requested when UsePAM=no");
 680
 681         if (sshpam_init(user) == -1)
 682                 fatal("PAM: initialisation failed");
 683 }
 684
 685 void
 686 finish_pam(void)
 687 {
 688         sshpam_cleanup();
 689 }
 690
 691 u_int
 692 do_pam_account(void)
 693 {
 694         if (sshpam_account_status != -1)
 695                 return (sshpam_account_status);
 696
 697         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 698         debug3("PAM: %s pam_acct_mgmt = %d", __func__, sshpam_err);
 699
 700         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
 701                 sshpam_account_status = 0;
 702                 return (sshpam_account_status);
 703         }
 704
 705         if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
 706                 pam_password_change_required(1);
 707
 708         sshpam_account_status = 1;
 709         return (sshpam_account_status);
 710 }
 711
 712 void
 713 do_pam_set_tty(const char *tty)
 714 {
 715         if (tty != NULL) {
 716                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 717                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 718                 if (sshpam_err != PAM_SUCCESS)
 719                         fatal("PAM: failed to set PAM_TTY: %s",
 720                             pam_strerror(sshpam_handle, sshpam_err));
 721         }
 722 }
 723
 724 void
 725 do_pam_setcred(int init)
 726 {
 727         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 728             (const void *)&null_conv);
 729         if (sshpam_err != PAM_SUCCESS)
 730                 fatal("PAM: failed to set PAM_CONV: %s",
 731                     pam_strerror(sshpam_handle, sshpam_err));
 732         if (init) {
 733                 debug("PAM: establishing credentials");
 734                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 735         } else {
 736                 debug("PAM: reinitializing credentials");
 737                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 738         }
 739         if (sshpam_err == PAM_SUCCESS) {
 740                 sshpam_cred_established = 1;
 741                 return;
 742         }
 743         if (sshpam_authenticated)
 744                 fatal("PAM: pam_setcred(): %s",
 745                     pam_strerror(sshpam_handle, sshpam_err));
 746         else
 747                 debug("PAM: pam_setcred(): %s",
 748                     pam_strerror(sshpam_handle, sshpam_err));
 749 }
 750
 751 static int
 752 pam_tty_conv(int n, const struct pam_message **msg,
 753     struct pam_response **resp, void *data)
 754 {
 755         char input[PAM_MAX_MSG_SIZE];
 756         struct pam_response *reply;
 757         int i;
 758
 759         debug3("PAM: %s called with %d messages", __func__, n);
 760
 761         *resp = NULL;
 762
 763         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
 764                 return (PAM_CONV_ERR);
 765
 766         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 767                 return (PAM_CONV_ERR);
 768         memset(reply, 0, n * sizeof(*reply));
 769
 770         for (i = 0; i < n; ++i) {
 771                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 772                 case PAM_PROMPT_ECHO_OFF:
 773                         reply[i].resp =
 774                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 775                             RP_ALLOW_STDIN);
 776                         reply[i].resp_retcode = PAM_SUCCESS;
 777                         break;
 778                 case PAM_PROMPT_ECHO_ON:
 779                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 780                         fgets(input, sizeof input, stdin);
 781                         reply[i].resp = xstrdup(input);
 782                         reply[i].resp_retcode = PAM_SUCCESS;
 783                         break;
 784                 case PAM_ERROR_MSG:
 785                 case PAM_TEXT_INFO:
 786                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 787                         reply[i].resp_retcode = PAM_SUCCESS;
 788                         break;
 789                 default:
 790                         goto fail;
 791                 }
 792         }
 793         *resp = reply;
 794         return (PAM_SUCCESS);
 795
 796  fail:
 797         for(i = 0; i < n; i++) {
 798                 if (reply[i].resp != NULL)
 799                         xfree(reply[i].resp);
 800         }
 801         xfree(reply);
 802         return (PAM_CONV_ERR);
 803 }
 804
 805 static struct pam_conv tty_conv = { pam_tty_conv, NULL };
 806
 807 /*
 808  * XXX this should be done in the authentication phase, but ssh1 doesn't
 809  * support that
 810  */
 811 void
 812 do_pam_chauthtok(void)
 813 {
 814         if (use_privsep)
 815                 fatal("Password expired (unable to change with privsep)");
 816         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 817             (const void *)&tty_conv);
 818         if (sshpam_err != PAM_SUCCESS)
 819                 fatal("PAM: failed to set PAM_CONV: %s",
 820                     pam_strerror(sshpam_handle, sshpam_err));
 821         debug("PAM: changing password");
 822         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 823         if (sshpam_err != PAM_SUCCESS)
 824                 fatal("PAM: pam_chauthtok(): %s",
 825                     pam_strerror(sshpam_handle, sshpam_err));
 826 }
 827
 828 static int
 829 pam_store_conv(int n, const struct pam_message **msg,
 830     struct pam_response **resp, void *data)
 831 {
 832         struct pam_response *reply;
 833         int i;
 834         size_t len;
 835
 836         debug3("PAM: %s called with %d messages", __func__, n);
 837         *resp = NULL;
 838
 839         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 840                 return (PAM_CONV_ERR);
 841
 842         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 843                 return (PAM_CONV_ERR);
 844         memset(reply, 0, n * sizeof(*reply));
 845
 846         for (i = 0; i < n; ++i) {
 847                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 848                 case PAM_ERROR_MSG:
 849                 case PAM_TEXT_INFO:
 850                         len = strlen(PAM_MSG_MEMBER(msg, i, msg));
 851                         buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
 852                         buffer_append(&loginmsg, "\n", 1 );
 853                         reply[i].resp_retcode = PAM_SUCCESS;
 854                         break;
 855                 default:
 856                         goto fail;
 857                 }
 858         }
 859         *resp = reply;
 860         return (PAM_SUCCESS);
 861
 862  fail:
 863         for(i = 0; i < n; i++) {
 864                 if (reply[i].resp != NULL)
 865                         xfree(reply[i].resp);
 866         }
 867         xfree(reply);
 868         return (PAM_CONV_ERR);
 869 }
 870
 871 static struct pam_conv store_conv = { pam_store_conv, NULL };
 872
 873 void
 874 do_pam_session(void)
 875 {
 876         debug3("PAM: opening session");
 877         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 878             (const void *)&store_conv);
 879         if (sshpam_err != PAM_SUCCESS)
 880                 fatal("PAM: failed to set PAM_CONV: %s",
 881                     pam_strerror(sshpam_handle, sshpam_err));
 882         sshpam_err = pam_open_session(sshpam_handle, 0);
 883         if (sshpam_err != PAM_SUCCESS)
 884                 fatal("PAM: pam_open_session(): %s",
 885                     pam_strerror(sshpam_handle, sshpam_err));
 886         sshpam_session_open = 1;
 887 }
 888
 889 /*
 890  * Set a PAM environment string. We need to do this so that the session
 891  * modules can handle things like Kerberos/GSI credentials that appear
 892  * during the ssh authentication process.
 893  */
 894 int
 895 do_pam_putenv(char *name, char *value)
 896 {
 897         int ret = 1;
 898 #ifdef HAVE_PAM_PUTENV
 899         char *compound;
 900         size_t len;
 901
 902         len = strlen(name) + strlen(value) + 2;
 903         compound = xmalloc(len);
 904
 905         snprintf(compound, len, "%s=%s", name, value);
 906         ret = pam_putenv(sshpam_handle, compound);
 907         xfree(compound);
 908 #endif
 909
 910         return (ret);
 911 }
 912
 913 char **
 914 fetch_pam_child_environment(void)
 915 {
 916         return sshpam_env;
 917 }
 918
 919 char **
 920 fetch_pam_environment(void)
 921 {
 922         return (pam_getenvlist(sshpam_handle));
 923 }
 924
 925 void
 926 free_pam_environment(char **env)
 927 {
 928         char **envp;
 929
 930         if (env == NULL)
 931                 return;
 932
 933         for (envp = env; *envp; envp++)
 934                 xfree(*envp);
 935         xfree(env);
 936 }
 937
 938 #endif /* USE_PAM */