crypto/openssh-3.8.1p1/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: auth-pam.c,v 1.100 2004/04/18 01:00:26 dtucker Exp $");
  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 extern u_int utmp_len;
  62
  63 #ifdef USE_POSIX_THREADS
  64 #include <pthread.h>
  65 /*
  66  * Avoid namespace clash when *not* using pthreads for systems *with*
  67  * pthreads, which unconditionally define pthread_t via sys/types.h
  68  * (e.g. Linux)
  69  */
  70 typedef pthread_t sp_pthread_t;
  71 #else
  72 typedef pid_t sp_pthread_t;
  73 #endif
  74
  75 struct pam_ctxt {
  76         sp_pthread_t     pam_thread;
  77         int              pam_psock;
  78         int              pam_csock;
  79         int              pam_done;
  80 };
  81
  82 static void sshpam_free_ctx(void *);
  83 static struct pam_ctxt *cleanup_ctxt;
  84
  85 #ifndef USE_POSIX_THREADS
  86 /*
  87  * Simulate threads with processes.
  88  */
  89
  90 static int sshpam_thread_status = -1;
  91 static mysig_t sshpam_oldsig;
  92
  93 static void
  94 sshpam_sigchld_handler(int sig)
  95 {
  96         if (cleanup_ctxt == NULL)
  97                 return; /* handler called after PAM cleanup, shouldn't happen */
  98         if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0) == -1)
  99                 return; /* couldn't wait for process */
 100         if (WIFSIGNALED(sshpam_thread_status) &&
 101             WTERMSIG(sshpam_thread_status) == SIGTERM)
 102                 return; /* terminated by pthread_cancel */
 103         if (!WIFEXITED(sshpam_thread_status))
 104                 fatal("PAM: authentication thread exited unexpectedly");
 105         if (WEXITSTATUS(sshpam_thread_status) != 0)
 106                 fatal("PAM: authentication thread exited uncleanly");
 107 }
 108
 109 static void
 110 pthread_exit(void *value __unused)
 111 {
 112         _exit(0);
 113 }
 114
 115 static int
 116 pthread_create(sp_pthread_t *thread, const void *attr __unused,
 117     void *(*thread_start)(void *), void *arg)
 118 {
 119         pid_t pid;
 120
 121         sshpam_thread_status = -1;
 122         switch ((pid = fork())) {
 123         case -1:
 124                 error("fork(): %s", strerror(errno));
 125                 return (-1);
 126         case 0:
 127                 thread_start(arg);
 128                 _exit(1);
 129         default:
 130                 *thread = pid;
 131                 sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
 132                 return (0);
 133         }
 134 }
 135
 136 static int
 137 pthread_cancel(sp_pthread_t thread)
 138 {
 139         signal(SIGCHLD, sshpam_oldsig);
 140         return (kill(thread, SIGTERM));
 141 }
 142
 143 static int
 144 pthread_join(sp_pthread_t thread, void **value __unused)
 145 {
 146         int status;
 147
 148         if (sshpam_thread_status != -1)
 149                 return (sshpam_thread_status);
 150         signal(SIGCHLD, sshpam_oldsig);
 151         waitpid(thread, &status, 0);
 152         return (status);
 153 }
 154 #endif
 155
 156
 157 static pam_handle_t *sshpam_handle = NULL;
 158 static int sshpam_err = 0;
 159 static int sshpam_authenticated = 0;
 160 static int sshpam_session_open = 0;
 161 static int sshpam_cred_established = 0;
 162 static int sshpam_account_status = -1;
 163 static char **sshpam_env = NULL;
 164 static Authctxt *sshpam_authctxt = NULL;
 165
 166 /* Some PAM implementations don't implement this */
 167 #ifndef HAVE_PAM_GETENVLIST
 168 static char **
 169 pam_getenvlist(pam_handle_t *pamh)
 170 {
 171         /*
 172          * XXX - If necessary, we can still support envrionment passing
 173          * for platforms without pam_getenvlist by searching for known
 174          * env vars (e.g. KRB5CCNAME) from the PAM environment.
 175          */
 176          return NULL;
 177 }
 178 #endif
 179
 180 void
 181 pam_password_change_required(int reqd)
 182 {
 183         debug3("%s %d", __func__, reqd);
 184         if (sshpam_authctxt == NULL)
 185                 fatal("%s: PAM authctxt not initialized", __func__);
 186         sshpam_authctxt->force_pwchange = reqd;
 187         if (reqd) {
 188                 no_port_forwarding_flag |= 2;
 189                 no_agent_forwarding_flag |= 2;
 190                 no_x11_forwarding_flag |= 2;
 191         } else {
 192                 no_port_forwarding_flag &= ~2;
 193                 no_agent_forwarding_flag &= ~2;
 194                 no_x11_forwarding_flag &= ~2;
 195         }
 196 }
 197
 198 /* Import regular and PAM environment from subprocess */
 199 static void
 200 import_environments(Buffer *b)
 201 {
 202         char *env;
 203         u_int i, num_env;
 204         int err;
 205
 206         debug3("PAM: %s entering", __func__);
 207
 208 #ifndef USE_POSIX_THREADS
 209         /* Import variables set by do_pam_account */
 210         sshpam_account_status = buffer_get_int(b);
 211         pam_password_change_required(buffer_get_int(b));
 212
 213         /* Import environment from subprocess */
 214         num_env = buffer_get_int(b);
 215         sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
 216         debug3("PAM: num env strings %d", num_env);
 217         for(i = 0; i < num_env; i++)
 218                 sshpam_env[i] = buffer_get_string(b, NULL);
 219
 220         sshpam_env[num_env] = NULL;
 221
 222         /* Import PAM environment from subprocess */
 223         num_env = buffer_get_int(b);
 224         debug("PAM: num PAM env strings %d", num_env);
 225         for(i = 0; i < num_env; i++) {
 226                 env = buffer_get_string(b, NULL);
 227
 228 #ifdef HAVE_PAM_PUTENV
 229                 /* Errors are not fatal here */
 230                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 231                         error("PAM: pam_putenv: %s",
 232                             pam_strerror(sshpam_handle, sshpam_err));
 233                 }
 234 #endif
 235         }
 236 #endif
 237 }
 238
 239 /*
 240  * Conversation function for authentication thread.
 241  */
 242 static int
 243 sshpam_thread_conv(int n, const struct pam_message **msg,
 244     struct pam_response **resp, void *data)
 245 {
 246         Buffer buffer;
 247         struct pam_ctxt *ctxt;
 248         struct pam_response *reply;
 249         int i;
 250
 251         debug3("PAM: %s entering, %d messages", __func__, n);
 252         *resp = NULL;
 253
 254         ctxt = data;
 255         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 256                 return (PAM_CONV_ERR);
 257
 258         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 259                 return (PAM_CONV_ERR);
 260         memset(reply, 0, n * sizeof(*reply));
 261
 262         buffer_init(&buffer);
 263         for (i = 0; i < n; ++i) {
 264                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 265                 case PAM_PROMPT_ECHO_OFF:
 266                         buffer_put_cstring(&buffer,
 267                             PAM_MSG_MEMBER(msg, i, msg));
 268                         if (ssh_msg_send(ctxt->pam_csock,
 269                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 270                                 goto fail;
 271                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 272                                 goto fail;
 273                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 274                                 goto fail;
 275                         reply[i].resp = buffer_get_string(&buffer, NULL);
 276                         break;
 277                 case PAM_PROMPT_ECHO_ON:
 278                         buffer_put_cstring(&buffer,
 279                             PAM_MSG_MEMBER(msg, i, msg));
 280                         if (ssh_msg_send(ctxt->pam_csock,
 281                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 282                                 goto fail;
 283                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 284                                 goto fail;
 285                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 286                                 goto fail;
 287                         reply[i].resp = buffer_get_string(&buffer, NULL);
 288                         break;
 289                 case PAM_ERROR_MSG:
 290                         buffer_put_cstring(&buffer,
 291                             PAM_MSG_MEMBER(msg, i, msg));
 292                         if (ssh_msg_send(ctxt->pam_csock,
 293                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 294                                 goto fail;
 295                         break;
 296                 case PAM_TEXT_INFO:
 297                         buffer_put_cstring(&buffer,
 298                             PAM_MSG_MEMBER(msg, i, msg));
 299                         if (ssh_msg_send(ctxt->pam_csock,
 300                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 301                                 goto fail;
 302                         break;
 303                 default:
 304                         goto fail;
 305                 }
 306                 buffer_clear(&buffer);
 307         }
 308         buffer_free(&buffer);
 309         *resp = reply;
 310         return (PAM_SUCCESS);
 311
 312  fail:
 313         for(i = 0; i < n; i++) {
 314                 if (reply[i].resp != NULL)
 315                         xfree(reply[i].resp);
 316         }
 317         xfree(reply);
 318         buffer_free(&buffer);
 319         return (PAM_CONV_ERR);
 320 }
 321
 322 /*
 323  * Authentication thread.
 324  */
 325 static void *
 326 sshpam_thread(void *ctxtp)
 327 {
 328         struct pam_ctxt *ctxt = ctxtp;
 329         Buffer buffer;
 330         struct pam_conv sshpam_conv;
 331 #ifndef USE_POSIX_THREADS
 332         extern char **environ;
 333         char **env_from_pam;
 334         u_int i;
 335         const char *pam_user;
 336
 337         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 338         setproctitle("%s [pam]", pam_user);
 339         environ[0] = NULL;
 340 #endif
 341
 342         sshpam_conv.conv = sshpam_thread_conv;
 343         sshpam_conv.appdata_ptr = ctxt;
 344
 345         if (sshpam_authctxt == NULL)
 346                 fatal("%s: PAM authctxt not initialized", __func__);
 347
 348         buffer_init(&buffer);
 349         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 350             (const void *)&sshpam_conv);
 351         if (sshpam_err != PAM_SUCCESS)
 352                 goto auth_fail;
 353         sshpam_err = pam_authenticate(sshpam_handle, 0);
 354         if (sshpam_err != PAM_SUCCESS)
 355                 goto auth_fail;
 356
 357         if (compat20) {
 358                 if (!do_pam_account())
 359                         goto auth_fail;
 360                 if (sshpam_authctxt->force_pwchange) {
 361                         sshpam_err = pam_chauthtok(sshpam_handle,
 362                             PAM_CHANGE_EXPIRED_AUTHTOK);
 363                         if (sshpam_err != PAM_SUCCESS)
 364                                 goto auth_fail;
 365                         pam_password_change_required(0);
 366                 }
 367         }
 368
 369         buffer_put_cstring(&buffer, "OK");
 370
 371 #ifndef USE_POSIX_THREADS
 372         /* Export variables set by do_pam_account */
 373         buffer_put_int(&buffer, sshpam_account_status);
 374         buffer_put_int(&buffer, sshpam_authctxt->force_pwchange);
 375
 376         /* Export any environment strings set in child */
 377         for(i = 0; environ[i] != NULL; i++)
 378                 ; /* Count */
 379         buffer_put_int(&buffer, i);
 380         for(i = 0; environ[i] != NULL; i++)
 381                 buffer_put_cstring(&buffer, environ[i]);
 382
 383         /* Export any environment strings set by PAM in child */
 384         env_from_pam = pam_getenvlist(sshpam_handle);
 385         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 386                 ; /* Count */
 387         buffer_put_int(&buffer, i);
 388         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 389                 buffer_put_cstring(&buffer, env_from_pam[i]);
 390 #endif /* USE_POSIX_THREADS */
 391
 392         /* XXX - can't do much about an error here */
 393         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 394         buffer_free(&buffer);
 395         pthread_exit(NULL);
 396
 397  auth_fail:
 398         buffer_put_cstring(&buffer,
 399             pam_strerror(sshpam_handle, sshpam_err));
 400         /* XXX - can't do much about an error here */
 401         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 402         buffer_free(&buffer);
 403         pthread_exit(NULL);
 404
 405         return (NULL); /* Avoid warning for non-pthread case */
 406 }
 407
 408 void
 409 sshpam_thread_cleanup(void)
 410 {
 411         struct pam_ctxt *ctxt = cleanup_ctxt;
 412
 413         debug3("PAM: %s entering", __func__);
 414         if (ctxt != NULL && ctxt->pam_thread != 0) {
 415                 pthread_cancel(ctxt->pam_thread);
 416                 pthread_join(ctxt->pam_thread, NULL);
 417                 close(ctxt->pam_psock);
 418                 close(ctxt->pam_csock);
 419                 memset(ctxt, 0, sizeof(*ctxt));
 420                 cleanup_ctxt = NULL;
 421         }
 422 }
 423
 424 static int
 425 sshpam_null_conv(int n, const struct pam_message **msg,
 426     struct pam_response **resp, void *data)
 427 {
 428         debug3("PAM: %s entering, %d messages", __func__, n);
 429         return (PAM_CONV_ERR);
 430 }
 431
 432 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 433
 434 void
 435 sshpam_cleanup(void)
 436 {
 437         debug("PAM: cleanup");
 438         if (sshpam_handle == NULL)
 439                 return;
 440         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 441         if (sshpam_cred_established) {
 442                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 443                 sshpam_cred_established = 0;
 444         }
 445         if (sshpam_session_open) {
 446                 pam_close_session(sshpam_handle, PAM_SILENT);
 447                 sshpam_session_open = 0;
 448         }
 449         sshpam_authenticated = 0;
 450         pam_end(sshpam_handle, sshpam_err);
 451         sshpam_handle = NULL;
 452 }
 453
 454 static int
 455 sshpam_init(Authctxt *authctxt)
 456 {
 457         extern char *__progname;
 458         const char *pam_rhost, *pam_user, *user = authctxt->user;
 459
 460         if (sshpam_handle != NULL) {
 461                 /* We already have a PAM context; check if the user matches */
 462                 sshpam_err = pam_get_item(sshpam_handle,
 463                     PAM_USER, (const void **)&pam_user);
 464                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 465                         return (0);
 466                 pam_end(sshpam_handle, sshpam_err);
 467                 sshpam_handle = NULL;
 468         }
 469         debug("PAM: initializing for \"%s\"", user);
 470         sshpam_err =
 471             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 472         sshpam_authctxt = authctxt;
 473
 474         if (sshpam_err != PAM_SUCCESS) {
 475                 pam_end(sshpam_handle, sshpam_err);
 476                 sshpam_handle = NULL;
 477                 return (-1);
 478         }
 479         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 480         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 481         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 482         if (sshpam_err != PAM_SUCCESS) {
 483                 pam_end(sshpam_handle, sshpam_err);
 484                 sshpam_handle = NULL;
 485                 return (-1);
 486         }
 487 #ifdef PAM_TTY_KLUDGE
 488         /*
 489          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 490          * sshd doesn't set the tty until too late in the auth process and
 491          * may not even set one (for tty-less connections)
 492          */
 493         debug("PAM: setting PAM_TTY to \"ssh\"");
 494         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 495         if (sshpam_err != PAM_SUCCESS) {
 496                 pam_end(sshpam_handle, sshpam_err);
 497                 sshpam_handle = NULL;
 498                 return (-1);
 499         }
 500 #endif
 501         return (0);
 502 }
 503
 504 static void *
 505 sshpam_init_ctx(Authctxt *authctxt)
 506 {
 507         struct pam_ctxt *ctxt;
 508         int socks[2];
 509
 510         debug3("PAM: %s entering", __func__);
 511         /* Refuse to start if we don't have PAM enabled */
 512         if (!options.use_pam)
 513                 return NULL;
 514
 515         /* Initialize PAM */
 516         if (sshpam_init(authctxt) == -1) {
 517                 error("PAM: initialization failed");
 518                 return (NULL);
 519         }
 520
 521         ctxt = xmalloc(sizeof *ctxt);
 522         memset(ctxt, 0, sizeof(*ctxt));
 523
 524         /* Start the authentication thread */
 525         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 526                 error("PAM: failed create sockets: %s", strerror(errno));
 527                 xfree(ctxt);
 528                 return (NULL);
 529         }
 530         ctxt->pam_psock = socks[0];
 531         ctxt->pam_csock = socks[1];
 532         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 533                 error("PAM: failed to start authentication thread: %s",
 534                     strerror(errno));
 535                 close(socks[0]);
 536                 close(socks[1]);
 537                 xfree(ctxt);
 538                 return (NULL);
 539         }
 540         cleanup_ctxt = ctxt;
 541         return (ctxt);
 542 }
 543
 544 static int
 545 sshpam_query(void *ctx, char **name, char **info,
 546     u_int *num, char ***prompts, u_int **echo_on)
 547 {
 548         Buffer buffer;
 549         struct pam_ctxt *ctxt = ctx;
 550         size_t plen;
 551         u_char type;
 552         char *msg;
 553         size_t len;
 554
 555         debug3("PAM: %s entering", __func__);
 556         buffer_init(&buffer);
 557         *name = xstrdup("");
 558         *info = xstrdup("");
 559         *prompts = xmalloc(sizeof(char *));
 560         **prompts = NULL;
 561         plen = 0;
 562         *echo_on = xmalloc(sizeof(u_int));
 563         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 564                 type = buffer_get_char(&buffer);
 565                 msg = buffer_get_string(&buffer, NULL);
 566                 switch (type) {
 567                 case PAM_PROMPT_ECHO_ON:
 568                 case PAM_PROMPT_ECHO_OFF:
 569                         *num = 1;
 570                         len = plen + strlen(msg) + 1;
 571                         **prompts = xrealloc(**prompts, len);
 572                         plen += snprintf(**prompts + plen, len, "%s", msg);
 573                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 574                         xfree(msg);
 575                         return (0);
 576                 case PAM_ERROR_MSG:
 577                 case PAM_TEXT_INFO:
 578                         /* accumulate messages */
 579                         len = plen + strlen(msg) + 2;
 580                         **prompts = xrealloc(**prompts, len);
 581                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 582                         xfree(msg);
 583                         break;
 584                 case PAM_SUCCESS:
 585                 case PAM_AUTH_ERR:
 586                         if (**prompts != NULL) {
 587                                 /* drain any accumulated messages */
 588                                 debug("PAM: %s", **prompts);
 589                                 buffer_append(&loginmsg, **prompts,
 590                                     strlen(**prompts));
 591                                 xfree(**prompts);
 592                                 **prompts = NULL;
 593                         }
 594                         if (type == PAM_SUCCESS) {
 595                                 import_environments(&buffer);
 596                                 *num = 0;
 597                                 **echo_on = 0;
 598                                 ctxt->pam_done = 1;
 599                                 xfree(msg);
 600                                 return (0);
 601                         }
 602                         error("PAM: %s for %s%.100s from %.100s", msg,
 603                             sshpam_authctxt->valid ? "" : "illegal user ",
 604                             sshpam_authctxt->user,
 605                             get_remote_name_or_ip(utmp_len, options.use_dns));
 606                         /* FALLTHROUGH */
 607                 default:
 608                         *num = 0;
 609                         **echo_on = 0;
 610                         xfree(msg);
 611                         ctxt->pam_done = -1;
 612                         return (-1);
 613                 }
 614         }
 615         return (-1);
 616 }
 617
 618 /* XXX - see also comment in auth-chall.c:verify_response */
 619 static int
 620 sshpam_respond(void *ctx, u_int num, char **resp)
 621 {
 622         Buffer buffer;
 623         struct pam_ctxt *ctxt = ctx;
 624
 625         debug2("PAM: %s entering, %d responses", __func__, num);
 626         switch (ctxt->pam_done) {
 627         case 1:
 628                 sshpam_authenticated = 1;
 629                 return (0);
 630         case 0:
 631                 break;
 632         default:
 633                 return (-1);
 634         }
 635         if (num != 1) {
 636                 error("PAM: expected one response, got %u", num);
 637                 return (-1);
 638         }
 639         buffer_init(&buffer);
 640         buffer_put_cstring(&buffer, *resp);
 641         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 642                 buffer_free(&buffer);
 643                 return (-1);
 644         }
 645         buffer_free(&buffer);
 646         return (1);
 647 }
 648
 649 static void
 650 sshpam_free_ctx(void *ctxtp)
 651 {
 652         struct pam_ctxt *ctxt = ctxtp;
 653
 654         debug3("PAM: %s entering", __func__);
 655         sshpam_thread_cleanup();
 656         xfree(ctxt);
 657         /*
 658          * We don't call sshpam_cleanup() here because we may need the PAM
 659          * handle at a later stage, e.g. when setting up a session.  It's
 660          * still on the cleanup list, so pam_end() *will* be called before
 661          * the server process terminates.
 662          */
 663 }
 664
 665 KbdintDevice sshpam_device = {
 666         "pam",
 667         sshpam_init_ctx,
 668         sshpam_query,
 669         sshpam_respond,
 670         sshpam_free_ctx
 671 };
 672
 673 KbdintDevice mm_sshpam_device = {
 674         "pam",
 675         mm_sshpam_init_ctx,
 676         mm_sshpam_query,
 677         mm_sshpam_respond,
 678         mm_sshpam_free_ctx
 679 };
 680
 681 /*
 682  * This replaces auth-pam.c
 683  */
 684 void
 685 start_pam(Authctxt *authctxt)
 686 {
 687         if (!options.use_pam)
 688                 fatal("PAM: initialisation requested when UsePAM=no");
 689
 690         if (sshpam_init(authctxt) == -1)
 691                 fatal("PAM: initialisation failed");
 692 }
 693
 694 void
 695 finish_pam(void)
 696 {
 697         sshpam_cleanup();
 698 }
 699
 700 u_int
 701 do_pam_account(void)
 702 {
 703         if (sshpam_account_status != -1)
 704                 return (sshpam_account_status);
 705
 706         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 707         debug3("PAM: %s pam_acct_mgmt = %d", __func__, sshpam_err);
 708
 709         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
 710                 sshpam_account_status = 0;
 711                 return (sshpam_account_status);
 712         }
 713
 714         if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
 715                 pam_password_change_required(1);
 716
 717         sshpam_account_status = 1;
 718         return (sshpam_account_status);
 719 }
 720
 721 void
 722 do_pam_set_tty(const char *tty)
 723 {
 724         if (tty != NULL) {
 725                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 726                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 727                 if (sshpam_err != PAM_SUCCESS)
 728                         fatal("PAM: failed to set PAM_TTY: %s",
 729                             pam_strerror(sshpam_handle, sshpam_err));
 730         }
 731 }
 732
 733 void
 734 do_pam_setcred(int init)
 735 {
 736         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 737             (const void *)&null_conv);
 738         if (sshpam_err != PAM_SUCCESS)
 739                 fatal("PAM: failed to set PAM_CONV: %s",
 740                     pam_strerror(sshpam_handle, sshpam_err));
 741         if (init) {
 742                 debug("PAM: establishing credentials");
 743                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 744         } else {
 745                 debug("PAM: reinitializing credentials");
 746                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 747         }
 748         if (sshpam_err == PAM_SUCCESS) {
 749                 sshpam_cred_established = 1;
 750                 return;
 751         }
 752         if (sshpam_authenticated)
 753                 fatal("PAM: pam_setcred(): %s",
 754                     pam_strerror(sshpam_handle, sshpam_err));
 755         else
 756                 debug("PAM: pam_setcred(): %s",
 757                     pam_strerror(sshpam_handle, sshpam_err));
 758 }
 759
 760 static int
 761 pam_tty_conv(int n, const struct pam_message **msg,
 762     struct pam_response **resp, void *data)
 763 {
 764         char input[PAM_MAX_MSG_SIZE];
 765         struct pam_response *reply;
 766         int i;
 767
 768         debug3("PAM: %s called with %d messages", __func__, n);
 769
 770         *resp = NULL;
 771
 772         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
 773                 return (PAM_CONV_ERR);
 774
 775         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 776                 return (PAM_CONV_ERR);
 777         memset(reply, 0, n * sizeof(*reply));
 778
 779         for (i = 0; i < n; ++i) {
 780                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 781                 case PAM_PROMPT_ECHO_OFF:
 782                         reply[i].resp =
 783                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 784                             RP_ALLOW_STDIN);
 785                         reply[i].resp_retcode = PAM_SUCCESS;
 786                         break;
 787                 case PAM_PROMPT_ECHO_ON:
 788                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 789                         fgets(input, sizeof input, stdin);
 790                         reply[i].resp = xstrdup(input);
 791                         reply[i].resp_retcode = PAM_SUCCESS;
 792                         break;
 793                 case PAM_ERROR_MSG:
 794                 case PAM_TEXT_INFO:
 795                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 796                         reply[i].resp_retcode = PAM_SUCCESS;
 797                         break;
 798                 default:
 799                         goto fail;
 800                 }
 801         }
 802         *resp = reply;
 803         return (PAM_SUCCESS);
 804
 805  fail:
 806         for(i = 0; i < n; i++) {
 807                 if (reply[i].resp != NULL)
 808                         xfree(reply[i].resp);
 809         }
 810         xfree(reply);
 811         return (PAM_CONV_ERR);
 812 }
 813
 814 static struct pam_conv tty_conv = { pam_tty_conv, NULL };
 815
 816 /*
 817  * XXX this should be done in the authentication phase, but ssh1 doesn't
 818  * support that
 819  */
 820 void
 821 do_pam_chauthtok(void)
 822 {
 823         if (use_privsep)
 824                 fatal("Password expired (unable to change with privsep)");
 825         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 826             (const void *)&tty_conv);
 827         if (sshpam_err != PAM_SUCCESS)
 828                 fatal("PAM: failed to set PAM_CONV: %s",
 829                     pam_strerror(sshpam_handle, sshpam_err));
 830         debug("PAM: changing password");
 831         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 832         if (sshpam_err != PAM_SUCCESS)
 833                 fatal("PAM: pam_chauthtok(): %s",
 834                     pam_strerror(sshpam_handle, sshpam_err));
 835 }
 836
 837 static int
 838 pam_store_conv(int n, const struct pam_message **msg,
 839     struct pam_response **resp, void *data)
 840 {
 841         struct pam_response *reply;
 842         int i;
 843         size_t len;
 844
 845         debug3("PAM: %s called with %d messages", __func__, n);
 846         *resp = NULL;
 847
 848         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 849                 return (PAM_CONV_ERR);
 850
 851         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 852                 return (PAM_CONV_ERR);
 853         memset(reply, 0, n * sizeof(*reply));
 854
 855         for (i = 0; i < n; ++i) {
 856                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 857                 case PAM_ERROR_MSG:
 858                 case PAM_TEXT_INFO:
 859                         len = strlen(PAM_MSG_MEMBER(msg, i, msg));
 860                         buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
 861                         buffer_append(&loginmsg, "\n", 1 );
 862                         reply[i].resp_retcode = PAM_SUCCESS;
 863                         break;
 864                 default:
 865                         goto fail;
 866                 }
 867         }
 868         *resp = reply;
 869         return (PAM_SUCCESS);
 870
 871  fail:
 872         for(i = 0; i < n; i++) {
 873                 if (reply[i].resp != NULL)
 874                         xfree(reply[i].resp);
 875         }
 876         xfree(reply);
 877         return (PAM_CONV_ERR);
 878 }
 879
 880 static struct pam_conv store_conv = { pam_store_conv, NULL };
 881
 882 void
 883 do_pam_session(void)
 884 {
 885         debug3("PAM: opening session");
 886         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 887             (const void *)&store_conv);
 888         if (sshpam_err != PAM_SUCCESS)
 889                 fatal("PAM: failed to set PAM_CONV: %s",
 890                     pam_strerror(sshpam_handle, sshpam_err));
 891         sshpam_err = pam_open_session(sshpam_handle, 0);
 892         if (sshpam_err != PAM_SUCCESS)
 893                 fatal("PAM: pam_open_session(): %s",
 894                     pam_strerror(sshpam_handle, sshpam_err));
 895         sshpam_session_open = 1;
 896 }
 897
 898 /*
 899  * Set a PAM environment string. We need to do this so that the session
 900  * modules can handle things like Kerberos/GSI credentials that appear
 901  * during the ssh authentication process.
 902  */
 903 int
 904 do_pam_putenv(char *name, char *value)
 905 {
 906         int ret = 1;
 907 #ifdef HAVE_PAM_PUTENV
 908         char *compound;
 909         size_t len;
 910
 911         len = strlen(name) + strlen(value) + 2;
 912         compound = xmalloc(len);
 913
 914         snprintf(compound, len, "%s=%s", name, value);
 915         ret = pam_putenv(sshpam_handle, compound);
 916         xfree(compound);
 917 #endif
 918
 919         return (ret);
 920 }
 921
 922 char **
 923 fetch_pam_child_environment(void)
 924 {
 925         return sshpam_env;
 926 }
 927
 928 char **
 929 fetch_pam_environment(void)
 930 {
 931         return (pam_getenvlist(sshpam_handle));
 932 }
 933
 934 void
 935 free_pam_environment(char **env)
 936 {
 937         char **envp;
 938
 939         if (env == NULL)
 940                 return;
 941
 942         for (envp = env; *envp; envp++)
 943                 xfree(*envp);
 944         xfree(env);
 945 }
 946
 947 #endif /* USE_PAM */