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_new_authtok_reqd = 0;
 159 static int sshpam_session_open = 0;
 160 static int sshpam_cred_established = 0;
 161 static int sshpam_account_status = -1;
 162 static char **sshpam_env = NULL;
 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         sshpam_new_authtok_reqd = 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         /* Import variables set by do_pam_account */
 205         sshpam_account_status = buffer_get_int(b);
 206         pam_password_change_required(buffer_get_int(b));
 207
 208         /* Import environment from subprocess */
 209         num_env = buffer_get_int(b);
 210         sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
 211         debug3("PAM: num env strings %d", num_env);
 212         for(i = 0; i < num_env; i++)
 213                 sshpam_env[i] = buffer_get_string(b, NULL);
 214
 215         sshpam_env[num_env] = NULL;
 216
 217         /* Import PAM environment from subprocess */
 218         num_env = buffer_get_int(b);
 219         debug("PAM: num PAM env strings %d", num_env);
 220         for(i = 0; i < num_env; i++) {
 221                 env = buffer_get_string(b, NULL);
 222
 223 #ifdef HAVE_PAM_PUTENV
 224                 /* Errors are not fatal here */
 225                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 226                         error("PAM: pam_putenv: %s",
 227                             pam_strerror(sshpam_handle, sshpam_err));
 228                 }
 229 #endif
 230         }
 231 }
 232
 233 /*
 234  * Conversation function for authentication thread.
 235  */
 236 static int
 237 sshpam_thread_conv(int n, const struct pam_message **msg,
 238     struct pam_response **resp, void *data)
 239 {
 240         Buffer buffer;
 241         struct pam_ctxt *ctxt;
 242         struct pam_response *reply;
 243         int i;
 244
 245         debug3("PAM: %s entering, %d responses", __func__, n);
 246         *resp = NULL;
 247
 248         ctxt = data;
 249         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 250                 return (PAM_CONV_ERR);
 251
 252         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 253                 return (PAM_CONV_ERR);
 254         memset(reply, 0, n * sizeof(*reply));
 255
 256         buffer_init(&buffer);
 257         for (i = 0; i < n; ++i) {
 258                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 259                 case PAM_PROMPT_ECHO_OFF:
 260                         buffer_put_cstring(&buffer,
 261                             PAM_MSG_MEMBER(msg, i, msg));
 262                         if (ssh_msg_send(ctxt->pam_csock,
 263                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 264                                 goto fail;
 265                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 266                                 goto fail;
 267                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 268                                 goto fail;
 269                         reply[i].resp = buffer_get_string(&buffer, NULL);
 270                         break;
 271                 case PAM_PROMPT_ECHO_ON:
 272                         buffer_put_cstring(&buffer,
 273                             PAM_MSG_MEMBER(msg, i, msg));
 274                         if (ssh_msg_send(ctxt->pam_csock,
 275                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 276                                 goto fail;
 277                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 278                                 goto fail;
 279                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 280                                 goto fail;
 281                         reply[i].resp = buffer_get_string(&buffer, NULL);
 282                         break;
 283                 case PAM_ERROR_MSG:
 284                         buffer_put_cstring(&buffer,
 285                             PAM_MSG_MEMBER(msg, i, msg));
 286                         if (ssh_msg_send(ctxt->pam_csock,
 287                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 288                                 goto fail;
 289                         break;
 290                 case PAM_TEXT_INFO:
 291                         buffer_put_cstring(&buffer,
 292                             PAM_MSG_MEMBER(msg, i, msg));
 293                         if (ssh_msg_send(ctxt->pam_csock,
 294                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 295                                 goto fail;
 296                         break;
 297                 default:
 298                         goto fail;
 299                 }
 300                 buffer_clear(&buffer);
 301         }
 302         buffer_free(&buffer);
 303         *resp = reply;
 304         return (PAM_SUCCESS);
 305
 306  fail:
 307         for(i = 0; i < n; i++) {
 308                 if (reply[i].resp != NULL)
 309                         xfree(reply[i].resp);
 310         }
 311         xfree(reply);
 312         buffer_free(&buffer);
 313         return (PAM_CONV_ERR);
 314 }
 315
 316 /*
 317  * Authentication thread.
 318  */
 319 static void *
 320 sshpam_thread(void *ctxtp)
 321 {
 322         struct pam_ctxt *ctxt = ctxtp;
 323         Buffer buffer;
 324         struct pam_conv sshpam_conv;
 325 #ifndef USE_POSIX_THREADS
 326         extern char **environ;
 327         char **env_from_pam;
 328         u_int i;
 329         const char *pam_user;
 330
 331         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 332         setproctitle("%s [pam]", pam_user);
 333         environ[0] = NULL;
 334 #endif
 335
 336         sshpam_conv.conv = sshpam_thread_conv;
 337         sshpam_conv.appdata_ptr = ctxt;
 338
 339         buffer_init(&buffer);
 340         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 341             (const void *)&sshpam_conv);
 342         if (sshpam_err != PAM_SUCCESS)
 343                 goto auth_fail;
 344         sshpam_err = pam_authenticate(sshpam_handle, 0);
 345         if (sshpam_err != PAM_SUCCESS)
 346                 goto auth_fail;
 347
 348         if (compat20) {
 349                 if (!do_pam_account())
 350                         goto auth_fail;
 351                 if (sshpam_new_authtok_reqd) {
 352                         sshpam_err = pam_chauthtok(sshpam_handle,
 353                             PAM_CHANGE_EXPIRED_AUTHTOK);
 354                         if (sshpam_err != PAM_SUCCESS)
 355                                 goto auth_fail;
 356                         pam_password_change_required(0);
 357                 }
 358         }
 359
 360         buffer_put_cstring(&buffer, "OK");
 361
 362 #ifndef USE_POSIX_THREADS
 363         /* Export variables set by do_pam_account */
 364         buffer_put_int(&buffer, sshpam_account_status);
 365         buffer_put_int(&buffer, sshpam_new_authtok_reqd);
 366
 367         /* Export any environment strings set in child */
 368         for(i = 0; environ[i] != NULL; i++)
 369                 ; /* Count */
 370         buffer_put_int(&buffer, i);
 371         for(i = 0; environ[i] != NULL; i++)
 372                 buffer_put_cstring(&buffer, environ[i]);
 373
 374         /* Export any environment strings set by PAM in child */
 375         env_from_pam = pam_getenvlist(sshpam_handle);
 376         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 377                 ; /* Count */
 378         buffer_put_int(&buffer, i);
 379         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 380                 buffer_put_cstring(&buffer, env_from_pam[i]);
 381 #endif /* USE_POSIX_THREADS */
 382
 383         /* XXX - can't do much about an error here */
 384         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 385         buffer_free(&buffer);
 386         pthread_exit(NULL);
 387
 388  auth_fail:
 389         buffer_put_cstring(&buffer,
 390             pam_strerror(sshpam_handle, sshpam_err));
 391         /* XXX - can't do much about an error here */
 392         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 393         buffer_free(&buffer);
 394         pthread_exit(NULL);
 395
 396         return (NULL); /* Avoid warning for non-pthread case */
 397 }
 398
 399 void
 400 sshpam_thread_cleanup(void)
 401 {
 402         struct pam_ctxt *ctxt = cleanup_ctxt;
 403
 404         debug3("PAM: %s entering", __func__);
 405         if (ctxt != NULL && ctxt->pam_thread != 0) {
 406                 pthread_cancel(ctxt->pam_thread);
 407                 pthread_join(ctxt->pam_thread, NULL);
 408                 close(ctxt->pam_psock);
 409                 close(ctxt->pam_csock);
 410                 memset(ctxt, 0, sizeof(*ctxt));
 411                 cleanup_ctxt = NULL;
 412         }
 413 }
 414
 415 static int
 416 sshpam_null_conv(int n, const struct pam_message **msg,
 417     struct pam_response **resp, void *data)
 418 {
 419         debug3("PAM: %s entering, %d responses", __func__, n);
 420         return (PAM_CONV_ERR);
 421 }
 422
 423 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 424
 425 void
 426 sshpam_cleanup(void)
 427 {
 428         debug("PAM: cleanup");
 429         if (sshpam_handle == NULL)
 430                 return;
 431         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 432         if (sshpam_cred_established) {
 433                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 434                 sshpam_cred_established = 0;
 435         }
 436         if (sshpam_session_open) {
 437                 pam_close_session(sshpam_handle, PAM_SILENT);
 438                 sshpam_session_open = 0;
 439         }
 440         sshpam_authenticated = sshpam_new_authtok_reqd = 0;
 441         pam_end(sshpam_handle, sshpam_err);
 442         sshpam_handle = NULL;
 443 }
 444
 445 static int
 446 sshpam_init(const char *user)
 447 {
 448         extern u_int utmp_len;
 449         extern char *__progname;
 450         const char *pam_rhost, *pam_user;
 451
 452         if (sshpam_handle != NULL) {
 453                 /* We already have a PAM context; check if the user matches */
 454                 sshpam_err = pam_get_item(sshpam_handle,
 455                     PAM_USER, (const void **)&pam_user);
 456                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 457                         return (0);
 458                 pam_end(sshpam_handle, sshpam_err);
 459                 sshpam_handle = NULL;
 460         }
 461         debug("PAM: initializing for \"%s\"", user);
 462         sshpam_err =
 463             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 464         if (sshpam_err != PAM_SUCCESS) {
 465                 pam_end(sshpam_handle, sshpam_err);
 466                 sshpam_handle = NULL;
 467                 return (-1);
 468         }
 469         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 470         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 471         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 472         if (sshpam_err != PAM_SUCCESS) {
 473                 pam_end(sshpam_handle, sshpam_err);
 474                 sshpam_handle = NULL;
 475                 return (-1);
 476         }
 477 #ifdef PAM_TTY_KLUDGE
 478         /*
 479          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 480          * sshd doesn't set the tty until too late in the auth process and
 481          * may not even set one (for tty-less connections)
 482          */
 483         debug("PAM: setting PAM_TTY to \"ssh\"");
 484         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 485         if (sshpam_err != PAM_SUCCESS) {
 486                 pam_end(sshpam_handle, sshpam_err);
 487                 sshpam_handle = NULL;
 488                 return (-1);
 489         }
 490 #endif
 491         return (0);
 492 }
 493
 494 static void *
 495 sshpam_init_ctx(Authctxt *authctxt)
 496 {
 497         struct pam_ctxt *ctxt;
 498         int socks[2];
 499
 500         debug3("PAM: %s entering", __func__);
 501         /* Refuse to start if we don't have PAM enabled */
 502         if (!options.use_pam)
 503                 return NULL;
 504
 505         /* Initialize PAM */
 506         if (sshpam_init(authctxt->user) == -1) {
 507                 error("PAM: initialization failed");
 508                 return (NULL);
 509         }
 510
 511         ctxt = xmalloc(sizeof *ctxt);
 512         memset(ctxt, 0, sizeof(*ctxt));
 513
 514         /* Start the authentication thread */
 515         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 516                 error("PAM: failed create sockets: %s", strerror(errno));
 517                 xfree(ctxt);
 518                 return (NULL);
 519         }
 520         ctxt->pam_psock = socks[0];
 521         ctxt->pam_csock = socks[1];
 522         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 523                 error("PAM: failed to start authentication thread: %s",
 524                     strerror(errno));
 525                 close(socks[0]);
 526                 close(socks[1]);
 527                 xfree(ctxt);
 528                 return (NULL);
 529         }
 530         cleanup_ctxt = ctxt;
 531         return (ctxt);
 532 }
 533
 534 static int
 535 sshpam_query(void *ctx, char **name, char **info,
 536     u_int *num, char ***prompts, u_int **echo_on)
 537 {
 538         Buffer buffer;
 539         struct pam_ctxt *ctxt = ctx;
 540         size_t plen;
 541         u_char type;
 542         char *msg;
 543         size_t len;
 544
 545         debug3("PAM: %s entering", __func__);
 546         buffer_init(&buffer);
 547         *name = xstrdup("");
 548         *info = xstrdup("");
 549         *prompts = xmalloc(sizeof(char *));
 550         **prompts = NULL;
 551         plen = 0;
 552         *echo_on = xmalloc(sizeof(u_int));
 553         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 554                 type = buffer_get_char(&buffer);
 555                 msg = buffer_get_string(&buffer, NULL);
 556                 switch (type) {
 557                 case PAM_PROMPT_ECHO_ON:
 558                 case PAM_PROMPT_ECHO_OFF:
 559                         *num = 1;
 560                         len = plen + strlen(msg) + 1;
 561                         **prompts = xrealloc(**prompts, len);
 562                         plen += snprintf(**prompts + plen, len, "%s", msg);
 563                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 564                         xfree(msg);
 565                         return (0);
 566                 case PAM_ERROR_MSG:
 567                 case PAM_TEXT_INFO:
 568                         /* accumulate messages */
 569                         len = plen + strlen(msg) + 2;
 570                         **prompts = xrealloc(**prompts, len);
 571                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 572                         xfree(msg);
 573                         break;
 574                 case PAM_SUCCESS:
 575                 case PAM_AUTH_ERR:
 576                         if (**prompts != NULL) {
 577                                 /* drain any accumulated messages */
 578                                 debug("PAM: %s", **prompts);
 579                                 buffer_append(&loginmsg, **prompts,
 580                                     strlen(**prompts));
 581                                 xfree(**prompts);
 582                                 **prompts = NULL;
 583                         }
 584                         if (type == PAM_SUCCESS) {
 585                                 import_environments(&buffer);
 586                                 *num = 0;
 587                                 **echo_on = 0;
 588                                 ctxt->pam_done = 1;
 589                                 xfree(msg);
 590                                 return (0);
 591                         }
 592                         error("PAM: %s", msg);
 593                         /* FALLTHROUGH */
 594                 default:
 595                         *num = 0;
 596                         **echo_on = 0;
 597                         xfree(msg);
 598                         ctxt->pam_done = -1;
 599                         return (-1);
 600                 }
 601         }
 602         return (-1);
 603 }
 604
 605 /* XXX - see also comment in auth-chall.c:verify_response */
 606 static int
 607 sshpam_respond(void *ctx, u_int num, char **resp)
 608 {
 609         Buffer buffer;
 610         struct pam_ctxt *ctxt = ctx;
 611
 612         debug2("PAM: %s entering, %d responses", __func__, num);
 613         switch (ctxt->pam_done) {
 614         case 1:
 615                 sshpam_authenticated = 1;
 616                 return (0);
 617         case 0:
 618                 break;
 619         default:
 620                 return (-1);
 621         }
 622         if (num != 1) {
 623                 error("PAM: expected one response, got %u", num);
 624                 return (-1);
 625         }
 626         buffer_init(&buffer);
 627         buffer_put_cstring(&buffer, *resp);
 628         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 629                 buffer_free(&buffer);
 630                 return (-1);
 631         }
 632         buffer_free(&buffer);
 633         return (1);
 634 }
 635
 636 static void
 637 sshpam_free_ctx(void *ctxtp)
 638 {
 639         struct pam_ctxt *ctxt = ctxtp;
 640
 641         debug3("PAM: %s entering", __func__);
 642         sshpam_thread_cleanup();
 643         xfree(ctxt);
 644         /*
 645          * We don't call sshpam_cleanup() here because we may need the PAM
 646          * handle at a later stage, e.g. when setting up a session.  It's
 647          * still on the cleanup list, so pam_end() *will* be called before
 648          * the server process terminates.
 649          */
 650 }
 651
 652 KbdintDevice sshpam_device = {
 653         "pam",
 654         sshpam_init_ctx,
 655         sshpam_query,
 656         sshpam_respond,
 657         sshpam_free_ctx
 658 };
 659
 660 KbdintDevice mm_sshpam_device = {
 661         "pam",
 662         mm_sshpam_init_ctx,
 663         mm_sshpam_query,
 664         mm_sshpam_respond,
 665         mm_sshpam_free_ctx
 666 };
 667
 668 /*
 669  * This replaces auth-pam.c
 670  */
 671 void
 672 start_pam(const char *user)
 673 {
 674         if (!options.use_pam)
 675                 fatal("PAM: initialisation requested when UsePAM=no");
 676
 677         if (sshpam_init(user) == -1)
 678                 fatal("PAM: initialisation failed");
 679 }
 680
 681 void
 682 finish_pam(void)
 683 {
 684         sshpam_cleanup();
 685 }
 686
 687 u_int
 688 do_pam_account(void)
 689 {
 690         if (sshpam_account_status != -1)
 691                 return (sshpam_account_status);
 692
 693         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 694         debug3("PAM: %s pam_acct_mgmt = %d", __func__, sshpam_err);
 695
 696         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
 697                 sshpam_account_status = 0;
 698                 return (sshpam_account_status);
 699         }
 700
 701         if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
 702                 pam_password_change_required(1);
 703
 704         sshpam_account_status = 1;
 705         return (sshpam_account_status);
 706 }
 707
 708 void
 709 do_pam_set_tty(const char *tty)
 710 {
 711         if (tty != NULL) {
 712                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 713                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 714                 if (sshpam_err != PAM_SUCCESS)
 715                         fatal("PAM: failed to set PAM_TTY: %s",
 716                             pam_strerror(sshpam_handle, sshpam_err));
 717         }
 718 }
 719
 720 void
 721 do_pam_setcred(int init)
 722 {
 723         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 724             (const void *)&null_conv);
 725         if (sshpam_err != PAM_SUCCESS)
 726                 fatal("PAM: failed to set PAM_CONV: %s",
 727                     pam_strerror(sshpam_handle, sshpam_err));
 728         if (init) {
 729                 debug("PAM: establishing credentials");
 730                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 731         } else {
 732                 debug("PAM: reinitializing credentials");
 733                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 734         }
 735         if (sshpam_err == PAM_SUCCESS) {
 736                 sshpam_cred_established = 1;
 737                 return;
 738         }
 739         if (sshpam_authenticated)
 740                 fatal("PAM: pam_setcred(): %s",
 741                     pam_strerror(sshpam_handle, sshpam_err));
 742         else
 743                 debug("PAM: pam_setcred(): %s",
 744                     pam_strerror(sshpam_handle, sshpam_err));
 745 }
 746
 747 int
 748 is_pam_password_change_required(void)
 749 {
 750         return (sshpam_new_authtok_reqd);
 751 }
 752
 753 static int
 754 pam_tty_conv(int n, const struct pam_message **msg,
 755     struct pam_response **resp, void *data)
 756 {
 757         char input[PAM_MAX_MSG_SIZE];
 758         struct pam_response *reply;
 759         int i;
 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 void
 829 do_pam_session(void)
 830 {
 831         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 832             (const void *)&tty_conv);
 833         if (sshpam_err != PAM_SUCCESS)
 834                 fatal("PAM: failed to set PAM_CONV: %s",
 835                     pam_strerror(sshpam_handle, sshpam_err));
 836         sshpam_err = pam_open_session(sshpam_handle, 0);
 837         if (sshpam_err != PAM_SUCCESS)
 838                 fatal("PAM: pam_open_session(): %s",
 839                     pam_strerror(sshpam_handle, sshpam_err));
 840         sshpam_session_open = 1;
 841 }
 842
 843 /*
 844  * Set a PAM environment string. We need to do this so that the session
 845  * modules can handle things like Kerberos/GSI credentials that appear
 846  * during the ssh authentication process.
 847  */
 848 int
 849 do_pam_putenv(char *name, char *value)
 850 {
 851         int ret = 1;
 852 #ifdef HAVE_PAM_PUTENV
 853         char *compound;
 854         size_t len;
 855
 856         len = strlen(name) + strlen(value) + 2;
 857         compound = xmalloc(len);
 858
 859         snprintf(compound, len, "%s=%s", name, value);
 860         ret = pam_putenv(sshpam_handle, compound);
 861         xfree(compound);
 862 #endif
 863
 864         return (ret);
 865 }
 866
 867 void
 868 print_pam_messages(void)
 869 {
 870         /* XXX */
 871 }
 872
 873 char **
 874 fetch_pam_child_environment(void)
 875 {
 876         return sshpam_env;
 877 }
 878
 879 char **
 880 fetch_pam_environment(void)
 881 {
 882         return (pam_getenvlist(sshpam_handle));
 883 }
 884
 885 void
 886 free_pam_environment(char **env)
 887 {
 888         char **envp;
 889
 890         if (env == NULL)
 891                 return;
 892
 893         for (envp = env; *envp; envp++)
 894                 xfree(*envp);
 895         xfree(env);
 896 }
 897
 898 #endif /* USE_PAM */