crypto/openssh/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  * Copyright (c) 2003,2004 Damien Miller <djm@mindrot.org>
  33  * Copyright (c) 2003,2004 Darren Tucker <dtucker@zip.com.au>
  34  *
  35  * Permission to use, copy, modify, and distribute this software for any
  36  * purpose with or without fee is hereby granted, provided that the above
  37  * copyright notice and this permission notice appear in all copies.
  38  *
  39  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  40  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  41  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  42  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  43  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  44  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  45  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  46  */
  47
  48 /* Based on FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des */
  49
  50 #include "includes.h"
  51
  52 #include <sys/types.h>
  53 #include <sys/stat.h>
  54 #include <sys/wait.h>
  55
  56 #include <errno.h>
  57 #include <signal.h>
  58 #include <stdarg.h>
  59 #include <string.h>
  60 #include <unistd.h>
  61
  62 #ifdef USE_PAM
  63 #if defined(HAVE_SECURITY_PAM_APPL_H)
  64 #include <security/pam_appl.h>
  65 #elif defined (HAVE_PAM_PAM_APPL_H)
  66 #include <pam/pam_appl.h>
  67 #endif
  68
  69 #if !defined(SSHD_PAM_SERVICE)
  70 extern char *__progname;
  71 # define SSHD_PAM_SERVICE               __progname
  72 #endif
  73
  74 /* OpenGroup RFC86.0 and XSSO specify no "const" on arguments */
  75 #ifdef PAM_SUN_CODEBASE
  76 # define sshpam_const           /* Solaris, HP-UX, SunOS */
  77 #else
  78 # define sshpam_const   const   /* LinuxPAM, OpenPAM, AIX */
  79 #endif
  80
  81 /* Ambiguity in spec: is it an array of pointers or a pointer to an array? */
  82 #ifdef PAM_SUN_CODEBASE
  83 # define PAM_MSG_MEMBER(msg, n, member) ((*(msg))[(n)].member)
  84 #else
  85 # define PAM_MSG_MEMBER(msg, n, member) ((msg)[(n)]->member)
  86 #endif
  87
  88 #include "xmalloc.h"
  89 #include "buffer.h"
  90 #include "key.h"
  91 #include "hostfile.h"
  92 #include "auth.h"
  93 #include "auth-pam.h"
  94 #include "canohost.h"
  95 #include "log.h"
  96 #include "msg.h"
  97 #include "packet.h"
  98 #include "misc.h"
  99 #include "servconf.h"
 100 #include "ssh2.h"
 101 #include "auth-options.h"
 102 #ifdef GSSAPI
 103 #include "ssh-gss.h"
 104 #endif
 105 #include "monitor_wrap.h"
 106
 107 extern ServerOptions options;
 108 extern Buffer loginmsg;
 109 extern u_int utmp_len;
 110
 111 /* so we don't silently change behaviour */
 112 #ifdef USE_POSIX_THREADS
 113 # error "USE_POSIX_THREADS replaced by UNSUPPORTED_POSIX_THREADS_HACK"
 114 #endif
 115
 116 /*
 117  * Formerly known as USE_POSIX_THREADS, using this is completely unsupported
 118  * and generally a bad idea.  Use at own risk and do not expect support if
 119  * this breaks.
 120  */
 121 #ifdef UNSUPPORTED_POSIX_THREADS_HACK
 122 #include <pthread.h>
 123 /*
 124  * Avoid namespace clash when *not* using pthreads for systems *with*
 125  * pthreads, which unconditionally define pthread_t via sys/types.h
 126  * (e.g. Linux)
 127  */
 128 typedef pthread_t sp_pthread_t;
 129 #else
 130 typedef pid_t sp_pthread_t;
 131 #endif
 132
 133 struct pam_ctxt {
 134         sp_pthread_t     pam_thread;
 135         int              pam_psock;
 136         int              pam_csock;
 137         int              pam_done;
 138 };
 139
 140 static void sshpam_free_ctx(void *);
 141 static struct pam_ctxt *cleanup_ctxt;
 142
 143 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
 144 /*
 145  * Simulate threads with processes.
 146  */
 147
 148 static int sshpam_thread_status = -1;
 149 static mysig_t sshpam_oldsig;
 150
 151 static void
 152 sshpam_sigchld_handler(int sig)
 153 {
 154         signal(SIGCHLD, SIG_DFL);
 155         if (cleanup_ctxt == NULL)
 156                 return; /* handler called after PAM cleanup, shouldn't happen */
 157         if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG)
 158             <= 0) {
 159                 /* PAM thread has not exitted, privsep slave must have */
 160                 kill(cleanup_ctxt->pam_thread, SIGTERM);
 161                 while (waitpid(cleanup_ctxt->pam_thread,
 162                     &sshpam_thread_status, 0) == -1) {
 163                         if (errno == EINTR)
 164                                 continue;
 165                         return;
 166                 }
 167         }
 168         if (WIFSIGNALED(sshpam_thread_status) &&
 169             WTERMSIG(sshpam_thread_status) == SIGTERM)
 170                 return; /* terminated by pthread_cancel */
 171         if (!WIFEXITED(sshpam_thread_status))
 172                 sigdie("PAM: authentication thread exited unexpectedly");
 173         if (WEXITSTATUS(sshpam_thread_status) != 0)
 174                 sigdie("PAM: authentication thread exited uncleanly");
 175 }
 176
 177 /* ARGSUSED */
 178 static void
 179 pthread_exit(void *value)
 180 {
 181         _exit(0);
 182 }
 183
 184 /* ARGSUSED */
 185 static int
 186 pthread_create(sp_pthread_t *thread, const void *attr,
 187     void *(*thread_start)(void *), void *arg)
 188 {
 189         pid_t pid;
 190         struct pam_ctxt *ctx = arg;
 191
 192         sshpam_thread_status = -1;
 193         switch ((pid = fork())) {
 194         case -1:
 195                 error("fork(): %s", strerror(errno));
 196                 return (-1);
 197         case 0:
 198                 close(ctx->pam_psock);
 199                 ctx->pam_psock = -1;
 200                 thread_start(arg);
 201                 _exit(1);
 202         default:
 203                 *thread = pid;
 204                 close(ctx->pam_csock);
 205                 ctx->pam_csock = -1;
 206                 sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
 207                 return (0);
 208         }
 209 }
 210
 211 static int
 212 pthread_cancel(sp_pthread_t thread)
 213 {
 214         signal(SIGCHLD, sshpam_oldsig);
 215         return (kill(thread, SIGTERM));
 216 }
 217
 218 /* ARGSUSED */
 219 static int
 220 pthread_join(sp_pthread_t thread, void **value)
 221 {
 222         int status;
 223
 224         if (sshpam_thread_status != -1)
 225                 return (sshpam_thread_status);
 226         signal(SIGCHLD, sshpam_oldsig);
 227         while (waitpid(thread, &status, 0) == -1) {
 228                 if (errno == EINTR)
 229                         continue;
 230                 fatal("%s: waitpid: %s", __func__, strerror(errno));
 231         }
 232         return (status);
 233 }
 234 #endif
 235
 236
 237 static pam_handle_t *sshpam_handle = NULL;
 238 static int sshpam_err = 0;
 239 static int sshpam_authenticated = 0;
 240 static int sshpam_session_open = 0;
 241 static int sshpam_cred_established = 0;
 242 static int sshpam_account_status = -1;
 243 static int sshpam_maxtries_reached = 0;
 244 static char **sshpam_env = NULL;
 245 static Authctxt *sshpam_authctxt = NULL;
 246 static const char *sshpam_password = NULL;
 247
 248 /* Some PAM implementations don't implement this */
 249 #ifndef HAVE_PAM_GETENVLIST
 250 static char **
 251 pam_getenvlist(pam_handle_t *pamh)
 252 {
 253         /*
 254          * XXX - If necessary, we can still support envrionment passing
 255          * for platforms without pam_getenvlist by searching for known
 256          * env vars (e.g. KRB5CCNAME) from the PAM environment.
 257          */
 258          return NULL;
 259 }
 260 #endif
 261
 262 /*
 263  * Some platforms, notably Solaris, do not enforce password complexity
 264  * rules during pam_chauthtok() if the real uid of the calling process
 265  * is 0, on the assumption that it's being called by "passwd" run by root.
 266  * This wraps pam_chauthtok and sets/restore the real uid so PAM will do
 267  * the right thing.
 268  */
 269 #ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID
 270 static int
 271 sshpam_chauthtok_ruid(pam_handle_t *pamh, int flags)
 272 {
 273         int result;
 274
 275         if (sshpam_authctxt == NULL)
 276                 fatal("PAM: sshpam_authctxt not initialized");
 277         if (setreuid(sshpam_authctxt->pw->pw_uid, -1) == -1)
 278                 fatal("%s: setreuid failed: %s", __func__, strerror(errno));
 279         result = pam_chauthtok(pamh, flags);
 280         if (setreuid(0, -1) == -1)
 281                 fatal("%s: setreuid failed: %s", __func__, strerror(errno));
 282         return result;
 283 }
 284 # define pam_chauthtok(a,b)     (sshpam_chauthtok_ruid((a), (b)))
 285 #endif
 286
 287 void
 288 sshpam_password_change_required(int reqd)
 289 {
 290         debug3("%s %d", __func__, reqd);
 291         if (sshpam_authctxt == NULL)
 292                 fatal("%s: PAM authctxt not initialized", __func__);
 293         sshpam_authctxt->force_pwchange = reqd;
 294         if (reqd) {
 295                 no_port_forwarding_flag |= 2;
 296                 no_agent_forwarding_flag |= 2;
 297                 no_x11_forwarding_flag |= 2;
 298         } else {
 299                 no_port_forwarding_flag &= ~2;
 300                 no_agent_forwarding_flag &= ~2;
 301                 no_x11_forwarding_flag &= ~2;
 302         }
 303 }
 304
 305 /* Import regular and PAM environment from subprocess */
 306 static void
 307 import_environments(Buffer *b)
 308 {
 309         char *env;
 310         u_int i, num_env;
 311         int err;
 312
 313         debug3("PAM: %s entering", __func__);
 314
 315 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
 316         /* Import variables set by do_pam_account */
 317         sshpam_account_status = buffer_get_int(b);
 318         sshpam_password_change_required(buffer_get_int(b));
 319
 320         /* Import environment from subprocess */
 321         num_env = buffer_get_int(b);
 322         if (num_env > 1024)
 323                 fatal("%s: received %u environment variables, expected <= 1024",
 324                     __func__, num_env);
 325         sshpam_env = xcalloc(num_env + 1, sizeof(*sshpam_env));
 326         debug3("PAM: num env strings %d", num_env);
 327         for(i = 0; i < num_env; i++)
 328                 sshpam_env[i] = buffer_get_string(b, NULL);
 329
 330         sshpam_env[num_env] = NULL;
 331
 332         /* Import PAM environment from subprocess */
 333         num_env = buffer_get_int(b);
 334         debug("PAM: num PAM env strings %d", num_env);
 335         for(i = 0; i < num_env; i++) {
 336                 env = buffer_get_string(b, NULL);
 337
 338 #ifdef HAVE_PAM_PUTENV
 339                 /* Errors are not fatal here */
 340                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 341                         error("PAM: pam_putenv: %s",
 342                             pam_strerror(sshpam_handle, sshpam_err));
 343                 }
 344 #endif
 345         }
 346 #endif
 347 }
 348
 349 /*
 350  * Conversation function for authentication thread.
 351  */
 352 static int
 353 sshpam_thread_conv(int n, sshpam_const struct pam_message **msg,
 354     struct pam_response **resp, void *data)
 355 {
 356         Buffer buffer;
 357         struct pam_ctxt *ctxt;
 358         struct pam_response *reply;
 359         int i;
 360
 361         debug3("PAM: %s entering, %d messages", __func__, n);
 362         *resp = NULL;
 363
 364         if (data == NULL) {
 365                 error("PAM: conversation function passed a null context");
 366                 return (PAM_CONV_ERR);
 367         }
 368         ctxt = data;
 369         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 370                 return (PAM_CONV_ERR);
 371
 372         if ((reply = calloc(n, sizeof(*reply))) == NULL)
 373                 return (PAM_CONV_ERR);
 374
 375         buffer_init(&buffer);
 376         for (i = 0; i < n; ++i) {
 377                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 378                 case PAM_PROMPT_ECHO_OFF:
 379                 case PAM_PROMPT_ECHO_ON:
 380                         buffer_put_cstring(&buffer,
 381                             PAM_MSG_MEMBER(msg, i, msg));
 382                         if (ssh_msg_send(ctxt->pam_csock,
 383                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 384                                 goto fail;
 385                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 386                                 goto fail;
 387                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 388                                 goto fail;
 389                         reply[i].resp = buffer_get_string(&buffer, NULL);
 390                         break;
 391                 case PAM_ERROR_MSG:
 392                 case PAM_TEXT_INFO:
 393                         buffer_put_cstring(&buffer,
 394                             PAM_MSG_MEMBER(msg, i, msg));
 395                         if (ssh_msg_send(ctxt->pam_csock,
 396                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 397                                 goto fail;
 398                         break;
 399                 default:
 400                         goto fail;
 401                 }
 402                 buffer_clear(&buffer);
 403         }
 404         buffer_free(&buffer);
 405         *resp = reply;
 406         return (PAM_SUCCESS);
 407
 408  fail:
 409         for(i = 0; i < n; i++) {
 410                 free(reply[i].resp);
 411         }
 412         free(reply);
 413         buffer_free(&buffer);
 414         return (PAM_CONV_ERR);
 415 }
 416
 417 /*
 418  * Authentication thread.
 419  */
 420 static void *
 421 sshpam_thread(void *ctxtp)
 422 {
 423         struct pam_ctxt *ctxt = ctxtp;
 424         Buffer buffer;
 425         struct pam_conv sshpam_conv;
 426         int flags = (options.permit_empty_passwd == 0 ?
 427             PAM_DISALLOW_NULL_AUTHTOK : 0);
 428 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
 429         extern char **environ;
 430         char **env_from_pam;
 431         u_int i;
 432         const char *pam_user;
 433         const char **ptr_pam_user = &pam_user;
 434         char *tz = getenv("TZ");
 435
 436         sshpam_err = pam_get_item(sshpam_handle, PAM_USER,
 437             (sshpam_const void **)ptr_pam_user);
 438         if (sshpam_err != PAM_SUCCESS)
 439                 goto auth_fail;
 440
 441         environ[0] = NULL;
 442         if (tz != NULL)
 443                 if (setenv("TZ", tz, 1) == -1)
 444                         error("PAM: could not set TZ environment: %s",
 445                             strerror(errno));
 446
 447         if (sshpam_authctxt != NULL) {
 448                 setproctitle("%s [pam]",
 449                     sshpam_authctxt->valid ? pam_user : "unknown");
 450         }
 451 #endif
 452
 453         sshpam_conv.conv = sshpam_thread_conv;
 454         sshpam_conv.appdata_ptr = ctxt;
 455
 456         if (sshpam_authctxt == NULL)
 457                 fatal("%s: PAM authctxt not initialized", __func__);
 458
 459         buffer_init(&buffer);
 460         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 461             (const void *)&sshpam_conv);
 462         if (sshpam_err != PAM_SUCCESS)
 463                 goto auth_fail;
 464         sshpam_err = pam_authenticate(sshpam_handle, flags);
 465         if (sshpam_err == PAM_MAXTRIES)
 466                 sshpam_set_maxtries_reached(1);
 467         if (sshpam_err != PAM_SUCCESS)
 468                 goto auth_fail;
 469
 470         if (!do_pam_account()) {
 471                 sshpam_err = PAM_ACCT_EXPIRED;
 472                 goto auth_fail;
 473         }
 474         if (sshpam_authctxt->force_pwchange) {
 475                 sshpam_err = pam_chauthtok(sshpam_handle,
 476                     PAM_CHANGE_EXPIRED_AUTHTOK);
 477                 if (sshpam_err != PAM_SUCCESS)
 478                         goto auth_fail;
 479                 sshpam_password_change_required(0);
 480         }
 481
 482         buffer_put_cstring(&buffer, "OK");
 483
 484 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
 485         /* Export variables set by do_pam_account */
 486         buffer_put_int(&buffer, sshpam_account_status);
 487         buffer_put_int(&buffer, sshpam_authctxt->force_pwchange);
 488
 489         /* Export any environment strings set in child */
 490         for(i = 0; environ[i] != NULL; i++)
 491                 ; /* Count */
 492         buffer_put_int(&buffer, i);
 493         for(i = 0; environ[i] != NULL; i++)
 494                 buffer_put_cstring(&buffer, environ[i]);
 495
 496         /* Export any environment strings set by PAM in child */
 497         env_from_pam = pam_getenvlist(sshpam_handle);
 498         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 499                 ; /* Count */
 500         buffer_put_int(&buffer, i);
 501         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 502                 buffer_put_cstring(&buffer, env_from_pam[i]);
 503 #endif /* UNSUPPORTED_POSIX_THREADS_HACK */
 504
 505         /* XXX - can't do much about an error here */
 506         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 507         buffer_free(&buffer);
 508         pthread_exit(NULL);
 509
 510  auth_fail:
 511         buffer_put_cstring(&buffer,
 512             pam_strerror(sshpam_handle, sshpam_err));
 513         /* XXX - can't do much about an error here */
 514         if (sshpam_err == PAM_ACCT_EXPIRED)
 515                 ssh_msg_send(ctxt->pam_csock, PAM_ACCT_EXPIRED, &buffer);
 516         else if (sshpam_maxtries_reached)
 517                 ssh_msg_send(ctxt->pam_csock, PAM_MAXTRIES, &buffer);
 518         else
 519                 ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 520         buffer_free(&buffer);
 521         pthread_exit(NULL);
 522
 523         return (NULL); /* Avoid warning for non-pthread case */
 524 }
 525
 526 void
 527 sshpam_thread_cleanup(void)
 528 {
 529         struct pam_ctxt *ctxt = cleanup_ctxt;
 530
 531         debug3("PAM: %s entering", __func__);
 532         if (ctxt != NULL && ctxt->pam_thread != 0) {
 533                 pthread_cancel(ctxt->pam_thread);
 534                 pthread_join(ctxt->pam_thread, NULL);
 535                 close(ctxt->pam_psock);
 536                 close(ctxt->pam_csock);
 537                 memset(ctxt, 0, sizeof(*ctxt));
 538                 cleanup_ctxt = NULL;
 539         }
 540 }
 541
 542 static int
 543 sshpam_null_conv(int n, sshpam_const struct pam_message **msg,
 544     struct pam_response **resp, void *data)
 545 {
 546         debug3("PAM: %s entering, %d messages", __func__, n);
 547         return (PAM_CONV_ERR);
 548 }
 549
 550 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 551
 552 static int
 553 sshpam_store_conv(int n, sshpam_const struct pam_message **msg,
 554     struct pam_response **resp, void *data)
 555 {
 556         struct pam_response *reply;
 557         int i;
 558         size_t len;
 559
 560         debug3("PAM: %s called with %d messages", __func__, n);
 561         *resp = NULL;
 562
 563         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 564                 return (PAM_CONV_ERR);
 565
 566         if ((reply = calloc(n, sizeof(*reply))) == NULL)
 567                 return (PAM_CONV_ERR);
 568
 569         for (i = 0; i < n; ++i) {
 570                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 571                 case PAM_ERROR_MSG:
 572                 case PAM_TEXT_INFO:
 573                         len = strlen(PAM_MSG_MEMBER(msg, i, msg));
 574                         buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
 575                         buffer_append(&loginmsg, "\n", 1 );
 576                         reply[i].resp_retcode = PAM_SUCCESS;
 577                         break;
 578                 default:
 579                         goto fail;
 580                 }
 581         }
 582         *resp = reply;
 583         return (PAM_SUCCESS);
 584
 585  fail:
 586         for(i = 0; i < n; i++) {
 587                 free(reply[i].resp);
 588         }
 589         free(reply);
 590         return (PAM_CONV_ERR);
 591 }
 592
 593 static struct pam_conv store_conv = { sshpam_store_conv, NULL };
 594
 595 void
 596 sshpam_cleanup(void)
 597 {
 598         if (sshpam_handle == NULL || (use_privsep && !mm_is_monitor()))
 599                 return;
 600         debug("PAM: cleanup");
 601         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 602         if (sshpam_session_open) {
 603                 debug("PAM: closing session");
 604                 pam_close_session(sshpam_handle, PAM_SILENT);
 605                 sshpam_session_open = 0;
 606         }
 607         if (sshpam_cred_established) {
 608                 debug("PAM: deleting credentials");
 609                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 610                 sshpam_cred_established = 0;
 611         }
 612         sshpam_authenticated = 0;
 613         pam_end(sshpam_handle, sshpam_err);
 614         sshpam_handle = NULL;
 615 }
 616
 617 static int
 618 sshpam_init(Authctxt *authctxt)
 619 {
 620         const char *pam_rhost, *pam_user, *user = authctxt->user;
 621         const char **ptr_pam_user = &pam_user;
 622         struct ssh *ssh = active_state; /* XXX */
 623
 624         if (sshpam_handle != NULL) {
 625                 /* We already have a PAM context; check if the user matches */
 626                 sshpam_err = pam_get_item(sshpam_handle,
 627                     PAM_USER, (sshpam_const void **)ptr_pam_user);
 628                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 629                         return (0);
 630                 pam_end(sshpam_handle, sshpam_err);
 631                 sshpam_handle = NULL;
 632         }
 633         debug("PAM: initializing for \"%s\"", user);
 634         sshpam_err =
 635             pam_start(SSHD_PAM_SERVICE, user, &store_conv, &sshpam_handle);
 636         sshpam_authctxt = authctxt;
 637
 638         if (sshpam_err != PAM_SUCCESS) {
 639                 pam_end(sshpam_handle, sshpam_err);
 640                 sshpam_handle = NULL;
 641                 return (-1);
 642         }
 643         pam_rhost = auth_get_canonical_hostname(ssh, options.use_dns);
 644         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 645         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 646         if (sshpam_err != PAM_SUCCESS) {
 647                 pam_end(sshpam_handle, sshpam_err);
 648                 sshpam_handle = NULL;
 649                 return (-1);
 650         }
 651 #ifdef PAM_TTY_KLUDGE
 652         /*
 653          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 654          * sshd doesn't set the tty until too late in the auth process and
 655          * may not even set one (for tty-less connections)
 656          */
 657         debug("PAM: setting PAM_TTY to \"ssh\"");
 658         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 659         if (sshpam_err != PAM_SUCCESS) {
 660                 pam_end(sshpam_handle, sshpam_err);
 661                 sshpam_handle = NULL;
 662                 return (-1);
 663         }
 664 #endif
 665         return (0);
 666 }
 667
 668 static void *
 669 sshpam_init_ctx(Authctxt *authctxt)
 670 {
 671         struct pam_ctxt *ctxt;
 672         int socks[2];
 673
 674         debug3("PAM: %s entering", __func__);
 675         /*
 676          * Refuse to start if we don't have PAM enabled or do_pam_account
 677          * has previously failed.
 678          */
 679         if (!options.use_pam || sshpam_account_status == 0)
 680                 return NULL;
 681
 682         /* Initialize PAM */
 683         if (sshpam_init(authctxt) == -1) {
 684                 error("PAM: initialization failed");
 685                 return (NULL);
 686         }
 687
 688         ctxt = xcalloc(1, sizeof *ctxt);
 689
 690         /* Start the authentication thread */
 691         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 692                 error("PAM: failed create sockets: %s", strerror(errno));
 693                 free(ctxt);
 694                 return (NULL);
 695         }
 696         ctxt->pam_psock = socks[0];
 697         ctxt->pam_csock = socks[1];
 698         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 699                 error("PAM: failed to start authentication thread: %s",
 700                     strerror(errno));
 701                 close(socks[0]);
 702                 close(socks[1]);
 703                 free(ctxt);
 704                 return (NULL);
 705         }
 706         cleanup_ctxt = ctxt;
 707         return (ctxt);
 708 }
 709
 710 static int
 711 sshpam_query(void *ctx, char **name, char **info,
 712     u_int *num, char ***prompts, u_int **echo_on)
 713 {
 714         struct ssh *ssh = active_state; /* XXX */
 715         Buffer buffer;
 716         struct pam_ctxt *ctxt = ctx;
 717         size_t plen;
 718         u_char type;
 719         char *msg;
 720         size_t len, mlen;
 721
 722         debug3("PAM: %s entering", __func__);
 723         buffer_init(&buffer);
 724         *name = xstrdup("");
 725         *info = xstrdup("");
 726         *prompts = xmalloc(sizeof(char *));
 727         **prompts = NULL;
 728         plen = 0;
 729         *echo_on = xmalloc(sizeof(u_int));
 730         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 731                 type = buffer_get_char(&buffer);
 732                 msg = buffer_get_string(&buffer, NULL);
 733                 mlen = strlen(msg);
 734                 switch (type) {
 735                 case PAM_PROMPT_ECHO_ON:
 736                 case PAM_PROMPT_ECHO_OFF:
 737                         *num = 1;
 738                         len = plen + mlen + 1;
 739                         **prompts = xreallocarray(**prompts, 1, len);
 740                         strlcpy(**prompts + plen, msg, len - plen);
 741                         plen += mlen;
 742                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 743                         free(msg);
 744                         return (0);
 745                 case PAM_ERROR_MSG:
 746                 case PAM_TEXT_INFO:
 747                         /* accumulate messages */
 748                         len = plen + mlen + 2;
 749                         **prompts = xreallocarray(**prompts, 1, len);
 750                         strlcpy(**prompts + plen, msg, len - plen);
 751                         plen += mlen;
 752                         strlcat(**prompts + plen, "\n", len - plen);
 753                         plen++;
 754                         free(msg);
 755                         break;
 756                 case PAM_ACCT_EXPIRED:
 757                 case PAM_MAXTRIES:
 758                         if (type == PAM_ACCT_EXPIRED)
 759                                 sshpam_account_status = 0;
 760                         if (type == PAM_MAXTRIES)
 761                                 sshpam_set_maxtries_reached(1);
 762                         /* FALLTHROUGH */
 763                 case PAM_AUTH_ERR:
 764                         debug3("PAM: %s", pam_strerror(sshpam_handle, type));
 765                         if (**prompts != NULL && strlen(**prompts) != 0) {
 766                                 *info = **prompts;
 767                                 **prompts = NULL;
 768                                 *num = 0;
 769                                 **echo_on = 0;
 770                                 ctxt->pam_done = -1;
 771                                 free(msg);
 772                                 return 0;
 773                         }
 774                         /* FALLTHROUGH */
 775                 case PAM_SUCCESS:
 776                         if (**prompts != NULL) {
 777                                 /* drain any accumulated messages */
 778                                 debug("PAM: %s", **prompts);
 779                                 buffer_append(&loginmsg, **prompts,
 780                                     strlen(**prompts));
 781                                 free(**prompts);
 782                                 **prompts = NULL;
 783                         }
 784                         if (type == PAM_SUCCESS) {
 785                                 if (!sshpam_authctxt->valid ||
 786                                     (sshpam_authctxt->pw->pw_uid == 0 &&
 787                                     options.permit_root_login != PERMIT_YES))
 788                                         fatal("Internal error: PAM auth "
 789                                             "succeeded when it should have "
 790                                             "failed");
 791                                 import_environments(&buffer);
 792                                 *num = 0;
 793                                 **echo_on = 0;
 794                                 ctxt->pam_done = 1;
 795                                 free(msg);
 796                                 return (0);
 797                         }
 798                         error("PAM: %s for %s%.100s from %.100s", msg,
 799                             sshpam_authctxt->valid ? "" : "illegal user ",
 800                             sshpam_authctxt->user,
 801                             auth_get_canonical_hostname(ssh, options.use_dns));
 802                         /* FALLTHROUGH */
 803                 default:
 804                         *num = 0;
 805                         **echo_on = 0;
 806                         free(msg);
 807                         ctxt->pam_done = -1;
 808                         return (-1);
 809                 }
 810         }
 811         return (-1);
 812 }
 813
 814 /*
 815  * Returns a junk password of identical length to that the user supplied.
 816  * Used to mitigate timing attacks against crypt(3)/PAM stacks that
 817  * vary processing time in proportion to password length.
 818  */
 819 static char *
 820 fake_password(const char *wire_password)
 821 {
 822         const char junk[] = "\b\n\r\177INCORRECT";
 823         char *ret = NULL;
 824         size_t i, l = wire_password != NULL ? strlen(wire_password) : 0;
 825
 826         if (l >= INT_MAX)
 827                 fatal("%s: password length too long: %zu", __func__, l);
 828
 829         ret = malloc(l + 1);
 830         if (ret == NULL)
 831                 return NULL;
 832         for (i = 0; i < l; i++)
 833                 ret[i] = junk[i % (sizeof(junk) - 1)];
 834         ret[i] = '\0';
 835         return ret;
 836 }
 837
 838 /* XXX - see also comment in auth-chall.c:verify_response */
 839 static int
 840 sshpam_respond(void *ctx, u_int num, char **resp)
 841 {
 842         Buffer buffer;
 843         struct pam_ctxt *ctxt = ctx;
 844         char *fake;
 845
 846         debug2("PAM: %s entering, %u responses", __func__, num);
 847         switch (ctxt->pam_done) {
 848         case 1:
 849                 sshpam_authenticated = 1;
 850                 return (0);
 851         case 0:
 852                 break;
 853         default:
 854                 return (-1);
 855         }
 856         if (num != 1) {
 857                 error("PAM: expected one response, got %u", num);
 858                 return (-1);
 859         }
 860         buffer_init(&buffer);
 861         if (sshpam_authctxt->valid &&
 862             (sshpam_authctxt->pw->pw_uid != 0 ||
 863             options.permit_root_login == PERMIT_YES))
 864                 buffer_put_cstring(&buffer, *resp);
 865         else {
 866                 fake = fake_password(*resp);
 867                 buffer_put_cstring(&buffer, fake);
 868                 free(fake);
 869         }
 870         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 871                 buffer_free(&buffer);
 872                 return (-1);
 873         }
 874         buffer_free(&buffer);
 875         return (1);
 876 }
 877
 878 static void
 879 sshpam_free_ctx(void *ctxtp)
 880 {
 881         struct pam_ctxt *ctxt = ctxtp;
 882
 883         debug3("PAM: %s entering", __func__);
 884         sshpam_thread_cleanup();
 885         free(ctxt);
 886         /*
 887          * We don't call sshpam_cleanup() here because we may need the PAM
 888          * handle at a later stage, e.g. when setting up a session.  It's
 889          * still on the cleanup list, so pam_end() *will* be called before
 890          * the server process terminates.
 891          */
 892 }
 893
 894 KbdintDevice sshpam_device = {
 895         "pam",
 896         sshpam_init_ctx,
 897         sshpam_query,
 898         sshpam_respond,
 899         sshpam_free_ctx
 900 };
 901
 902 KbdintDevice mm_sshpam_device = {
 903         "pam",
 904         mm_sshpam_init_ctx,
 905         mm_sshpam_query,
 906         mm_sshpam_respond,
 907         mm_sshpam_free_ctx
 908 };
 909
 910 /*
 911  * This replaces auth-pam.c
 912  */
 913 void
 914 start_pam(Authctxt *authctxt)
 915 {
 916         if (!options.use_pam)
 917                 fatal("PAM: initialisation requested when UsePAM=no");
 918
 919         if (sshpam_init(authctxt) == -1)
 920                 fatal("PAM: initialisation failed");
 921 }
 922
 923 void
 924 finish_pam(void)
 925 {
 926         sshpam_cleanup();
 927 }
 928
 929 static void
 930 expose_authinfo(const char *caller)
 931 {
 932         char *auth_info;
 933
 934         /*
 935          * Expose authentication information to PAM.
 936          * The enviornment variable is versioned. Please increment the
 937          * version suffix if the format of session_info changes.
 938          */
 939         if (sshpam_authctxt->session_info == NULL)
 940                 auth_info = xstrdup("");
 941         else if ((auth_info = sshbuf_dup_string(
 942             sshpam_authctxt->session_info)) == NULL)
 943                 fatal("%s: sshbuf_dup_string failed", __func__);
 944
 945         debug2("%s: auth information in SSH_AUTH_INFO_0", caller);
 946         do_pam_putenv("SSH_AUTH_INFO_0", auth_info);
 947         free(auth_info);
 948 }
 949
 950 u_int
 951 do_pam_account(void)
 952 {
 953         debug("%s: called", __func__);
 954         if (sshpam_account_status != -1)
 955                 return (sshpam_account_status);
 956
 957         expose_authinfo(__func__);
 958
 959         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 960         debug3("PAM: %s pam_acct_mgmt = %d (%s)", __func__, sshpam_err,
 961             pam_strerror(sshpam_handle, sshpam_err));
 962
 963         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
 964                 sshpam_account_status = 0;
 965                 return (sshpam_account_status);
 966         }
 967
 968         if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
 969                 sshpam_password_change_required(1);
 970
 971         sshpam_account_status = 1;
 972         return (sshpam_account_status);
 973 }
 974
 975 void
 976 do_pam_setcred(int init)
 977 {
 978         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 979             (const void *)&store_conv);
 980         if (sshpam_err != PAM_SUCCESS)
 981                 fatal("PAM: failed to set PAM_CONV: %s",
 982                     pam_strerror(sshpam_handle, sshpam_err));
 983         if (init) {
 984                 debug("PAM: establishing credentials");
 985                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 986         } else {
 987                 debug("PAM: reinitializing credentials");
 988                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 989         }
 990         if (sshpam_err == PAM_SUCCESS) {
 991                 sshpam_cred_established = 1;
 992                 return;
 993         }
 994         if (sshpam_authenticated)
 995                 fatal("PAM: pam_setcred(): %s",
 996                     pam_strerror(sshpam_handle, sshpam_err));
 997         else
 998                 debug("PAM: pam_setcred(): %s",
 999                     pam_strerror(sshpam_handle, sshpam_err));
1000 }
1001
1002 static int
1003 sshpam_tty_conv(int n, sshpam_const struct pam_message **msg,
1004     struct pam_response **resp, void *data)
1005 {
1006         char input[PAM_MAX_MSG_SIZE];
1007         struct pam_response *reply;
1008         int i;
1009
1010         debug3("PAM: %s called with %d messages", __func__, n);
1011
1012         *resp = NULL;
1013
1014         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
1015                 return (PAM_CONV_ERR);
1016
1017         if ((reply = calloc(n, sizeof(*reply))) == NULL)
1018                 return (PAM_CONV_ERR);
1019
1020         for (i = 0; i < n; ++i) {
1021                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
1022                 case PAM_PROMPT_ECHO_OFF:
1023                         reply[i].resp =
1024                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
1025                             RP_ALLOW_STDIN);
1026                         reply[i].resp_retcode = PAM_SUCCESS;
1027                         break;
1028                 case PAM_PROMPT_ECHO_ON:
1029                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
1030                         if (fgets(input, sizeof input, stdin) == NULL)
1031                                 input[0] = '\0';
1032                         if ((reply[i].resp = strdup(input)) == NULL)
1033                                 goto fail;
1034                         reply[i].resp_retcode = PAM_SUCCESS;
1035                         break;
1036                 case PAM_ERROR_MSG:
1037                 case PAM_TEXT_INFO:
1038                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
1039                         reply[i].resp_retcode = PAM_SUCCESS;
1040                         break;
1041                 default:
1042                         goto fail;
1043                 }
1044         }
1045         *resp = reply;
1046         return (PAM_SUCCESS);
1047
1048  fail:
1049         for(i = 0; i < n; i++) {
1050                 free(reply[i].resp);
1051         }
1052         free(reply);
1053         return (PAM_CONV_ERR);
1054 }
1055
1056 static struct pam_conv tty_conv = { sshpam_tty_conv, NULL };
1057
1058 /*
1059  * XXX this should be done in the authentication phase, but ssh1 doesn't
1060  * support that
1061  */
1062 void
1063 do_pam_chauthtok(void)
1064 {
1065         if (use_privsep)
1066                 fatal("Password expired (unable to change with privsep)");
1067         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1068             (const void *)&tty_conv);
1069         if (sshpam_err != PAM_SUCCESS)
1070                 fatal("PAM: failed to set PAM_CONV: %s",
1071                     pam_strerror(sshpam_handle, sshpam_err));
1072         debug("PAM: changing password");
1073         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
1074         if (sshpam_err != PAM_SUCCESS)
1075                 fatal("PAM: pam_chauthtok(): %s",
1076                     pam_strerror(sshpam_handle, sshpam_err));
1077 }
1078
1079 void
1080 do_pam_session(void)
1081 {
1082         debug3("PAM: opening session");
1083
1084         expose_authinfo(__func__);
1085
1086         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1087             (const void *)&store_conv);
1088         if (sshpam_err != PAM_SUCCESS)
1089                 fatal("PAM: failed to set PAM_CONV: %s",
1090                     pam_strerror(sshpam_handle, sshpam_err));
1091         sshpam_err = pam_open_session(sshpam_handle, 0);
1092         if (sshpam_err == PAM_SUCCESS)
1093                 sshpam_session_open = 1;
1094         else {
1095                 sshpam_session_open = 0;
1096                 disable_forwarding();
1097                 error("PAM: pam_open_session(): %s",
1098                     pam_strerror(sshpam_handle, sshpam_err));
1099         }
1100
1101 }
1102
1103 int
1104 is_pam_session_open(void)
1105 {
1106         return sshpam_session_open;
1107 }
1108
1109 /*
1110  * Set a PAM environment string. We need to do this so that the session
1111  * modules can handle things like Kerberos/GSI credentials that appear
1112  * during the ssh authentication process.
1113  */
1114 int
1115 do_pam_putenv(char *name, char *value)
1116 {
1117         int ret = 1;
1118 #ifdef HAVE_PAM_PUTENV
1119         char *compound;
1120         size_t len;
1121
1122         len = strlen(name) + strlen(value) + 2;
1123         compound = xmalloc(len);
1124
1125         snprintf(compound, len, "%s=%s", name, value);
1126         ret = pam_putenv(sshpam_handle, compound);
1127         free(compound);
1128 #endif
1129
1130         return (ret);
1131 }
1132
1133 char **
1134 fetch_pam_child_environment(void)
1135 {
1136         return sshpam_env;
1137 }
1138
1139 char **
1140 fetch_pam_environment(void)
1141 {
1142         return (pam_getenvlist(sshpam_handle));
1143 }
1144
1145 void
1146 free_pam_environment(char **env)
1147 {
1148         char **envp;
1149
1150         if (env == NULL)
1151                 return;
1152
1153         for (envp = env; *envp; envp++)
1154                 free(*envp);
1155         free(env);
1156 }
1157
1158 /*
1159  * "Blind" conversation function for password authentication.  Assumes that
1160  * echo-off prompts are for the password and stores messages for later
1161  * display.
1162  */
1163 static int
1164 sshpam_passwd_conv(int n, sshpam_const struct pam_message **msg,
1165     struct pam_response **resp, void *data)
1166 {
1167         struct pam_response *reply;
1168         int i;
1169         size_t len;
1170
1171         debug3("PAM: %s called with %d messages", __func__, n);
1172
1173         *resp = NULL;
1174
1175         if (n <= 0 || n > PAM_MAX_NUM_MSG)
1176                 return (PAM_CONV_ERR);
1177
1178         if ((reply = calloc(n, sizeof(*reply))) == NULL)
1179                 return (PAM_CONV_ERR);
1180
1181         for (i = 0; i < n; ++i) {
1182                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
1183                 case PAM_PROMPT_ECHO_OFF:
1184                         if (sshpam_password == NULL)
1185                                 goto fail;
1186                         if ((reply[i].resp = strdup(sshpam_password)) == NULL)
1187                                 goto fail;
1188                         reply[i].resp_retcode = PAM_SUCCESS;
1189                         break;
1190                 case PAM_ERROR_MSG:
1191                 case PAM_TEXT_INFO:
1192                         len = strlen(PAM_MSG_MEMBER(msg, i, msg));
1193                         if (len > 0) {
1194                                 buffer_append(&loginmsg,
1195                                     PAM_MSG_MEMBER(msg, i, msg), len);
1196                                 buffer_append(&loginmsg, "\n", 1);
1197                         }
1198                         if ((reply[i].resp = strdup("")) == NULL)
1199                                 goto fail;
1200                         reply[i].resp_retcode = PAM_SUCCESS;
1201                         break;
1202                 default:
1203                         goto fail;
1204                 }
1205         }
1206         *resp = reply;
1207         return (PAM_SUCCESS);
1208
1209  fail:
1210         for(i = 0; i < n; i++) {
1211                 free(reply[i].resp);
1212         }
1213         free(reply);
1214         return (PAM_CONV_ERR);
1215 }
1216
1217 static struct pam_conv passwd_conv = { sshpam_passwd_conv, NULL };
1218
1219 /*
1220  * Attempt password authentication via PAM
1221  */
1222 int
1223 sshpam_auth_passwd(Authctxt *authctxt, const char *password)
1224 {
1225         int flags = (options.permit_empty_passwd == 0 ?
1226             PAM_DISALLOW_NULL_AUTHTOK : 0);
1227         char *fake = NULL;
1228
1229         if (!options.use_pam || sshpam_handle == NULL)
1230                 fatal("PAM: %s called when PAM disabled or failed to "
1231                     "initialise.", __func__);
1232
1233         sshpam_password = password;
1234         sshpam_authctxt = authctxt;
1235
1236         /*
1237          * If the user logging in is invalid, or is root but is not permitted
1238          * by PermitRootLogin, use an invalid password to prevent leaking
1239          * information via timing (eg if the PAM config has a delay on fail).
1240          */
1241         if (!authctxt->valid || (authctxt->pw->pw_uid == 0 &&
1242             options.permit_root_login != PERMIT_YES))
1243                 sshpam_password = fake = fake_password(password);
1244
1245         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1246             (const void *)&passwd_conv);
1247         if (sshpam_err != PAM_SUCCESS)
1248                 fatal("PAM: %s: failed to set PAM_CONV: %s", __func__,
1249                     pam_strerror(sshpam_handle, sshpam_err));
1250
1251         sshpam_err = pam_authenticate(sshpam_handle, flags);
1252         sshpam_password = NULL;
1253         free(fake);
1254         if (sshpam_err == PAM_MAXTRIES)
1255                 sshpam_set_maxtries_reached(1);
1256         if (sshpam_err == PAM_SUCCESS && authctxt->valid) {
1257                 debug("PAM: password authentication accepted for %.100s",
1258                     authctxt->user);
1259                 return 1;
1260         } else {
1261                 debug("PAM: password authentication failed for %.100s: %s",
1262                     authctxt->valid ? authctxt->user : "an illegal user",
1263                     pam_strerror(sshpam_handle, sshpam_err));
1264                 return 0;
1265         }
1266 }
1267
1268 int
1269 sshpam_get_maxtries_reached(void)
1270 {
1271         return sshpam_maxtries_reached;
1272 }
1273
1274 void
1275 sshpam_set_maxtries_reached(int reached)
1276 {
1277         if (reached == 0 || sshpam_maxtries_reached)
1278                 return;
1279         sshpam_maxtries_reached = 1;
1280         options.password_authentication = 0;
1281         options.kbd_interactive_authentication = 0;
1282         options.challenge_response_authentication = 0;
1283 }
1284 #endif /* USE_PAM */