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 #include "blacklist_client.h"
 107
 108 extern ServerOptions options;
 109 extern Buffer loginmsg;
 110 extern int compat20;
 111 extern u_int utmp_len;
 112
 113 /* so we don't silently change behaviour */
 114 #ifdef USE_POSIX_THREADS
 115 # error "USE_POSIX_THREADS replaced by UNSUPPORTED_POSIX_THREADS_HACK"
 116 #endif
 117
 118 /*
 119  * Formerly known as USE_POSIX_THREADS, using this is completely unsupported
 120  * and generally a bad idea.  Use at own risk and do not expect support if
 121  * this breaks.
 122  */
 123 #ifdef UNSUPPORTED_POSIX_THREADS_HACK
 124 #include <pthread.h>
 125 /*
 126  * Avoid namespace clash when *not* using pthreads for systems *with*
 127  * pthreads, which unconditionally define pthread_t via sys/types.h
 128  * (e.g. Linux)
 129  */
 130 typedef pthread_t sp_pthread_t;
 131 #else
 132 typedef pid_t sp_pthread_t;
 133 #endif
 134
 135 struct pam_ctxt {
 136         sp_pthread_t     pam_thread;
 137         int              pam_psock;
 138         int              pam_csock;
 139         int              pam_done;
 140 };
 141
 142 static void sshpam_free_ctx(void *);
 143 static struct pam_ctxt *cleanup_ctxt;
 144
 145 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
 146 /*
 147  * Simulate threads with processes.
 148  */
 149
 150 static int sshpam_thread_status = -1;
 151 static mysig_t sshpam_oldsig;
 152
 153 static void
 154 sshpam_sigchld_handler(int sig)
 155 {
 156         signal(SIGCHLD, SIG_DFL);
 157         if (cleanup_ctxt == NULL)
 158                 return; /* handler called after PAM cleanup, shouldn't happen */
 159         if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG)
 160             <= 0) {
 161                 /* PAM thread has not exitted, privsep slave must have */
 162                 kill(cleanup_ctxt->pam_thread, SIGTERM);
 163                 while (waitpid(cleanup_ctxt->pam_thread,
 164                     &sshpam_thread_status, 0) == -1) {
 165                         if (errno == EINTR)
 166                                 continue;
 167                         return;
 168                 }
 169         }
 170         if (WIFSIGNALED(sshpam_thread_status) &&
 171             WTERMSIG(sshpam_thread_status) == SIGTERM)
 172                 return; /* terminated by pthread_cancel */
 173         if (!WIFEXITED(sshpam_thread_status))
 174                 sigdie("PAM: authentication thread exited unexpectedly");
 175         if (WEXITSTATUS(sshpam_thread_status) != 0)
 176                 sigdie("PAM: authentication thread exited uncleanly");
 177 }
 178
 179 /* ARGSUSED */
 180 static void
 181 pthread_exit(void *value)
 182 {
 183         _exit(0);
 184 }
 185
 186 /* ARGSUSED */
 187 static int
 188 pthread_create(sp_pthread_t *thread, const void *attr,
 189     void *(*thread_start)(void *), void *arg)
 190 {
 191         pid_t pid;
 192         struct pam_ctxt *ctx = arg;
 193
 194         sshpam_thread_status = -1;
 195         switch ((pid = fork())) {
 196         case -1:
 197                 error("fork(): %s", strerror(errno));
 198                 return (-1);
 199         case 0:
 200                 close(ctx->pam_psock);
 201                 ctx->pam_psock = -1;
 202                 thread_start(arg);
 203                 _exit(1);
 204         default:
 205                 *thread = pid;
 206                 close(ctx->pam_csock);
 207                 ctx->pam_csock = -1;
 208                 sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
 209                 return (0);
 210         }
 211 }
 212
 213 static int
 214 pthread_cancel(sp_pthread_t thread)
 215 {
 216         signal(SIGCHLD, sshpam_oldsig);
 217         return (kill(thread, SIGTERM));
 218 }
 219
 220 /* ARGSUSED */
 221 static int
 222 pthread_join(sp_pthread_t thread, void **value)
 223 {
 224         int status;
 225
 226         if (sshpam_thread_status != -1)
 227                 return (sshpam_thread_status);
 228         signal(SIGCHLD, sshpam_oldsig);
 229         while (waitpid(thread, &status, 0) == -1) {
 230                 if (errno == EINTR)
 231                         continue;
 232                 fatal("%s: waitpid: %s", __func__, strerror(errno));
 233         }
 234         return (status);
 235 }
 236 #endif
 237
 238
 239 static pam_handle_t *sshpam_handle = NULL;
 240 static int sshpam_err = 0;
 241 static int sshpam_authenticated = 0;
 242 static int sshpam_session_open = 0;
 243 static int sshpam_cred_established = 0;
 244 static int sshpam_account_status = -1;
 245 static int sshpam_maxtries_reached = 0;
 246 static char **sshpam_env = NULL;
 247 static Authctxt *sshpam_authctxt = NULL;
 248 static const char *sshpam_password = NULL;
 249
 250 /* Some PAM implementations don't implement this */
 251 #ifndef HAVE_PAM_GETENVLIST
 252 static char **
 253 pam_getenvlist(pam_handle_t *pamh)
 254 {
 255         /*
 256          * XXX - If necessary, we can still support envrionment passing
 257          * for platforms without pam_getenvlist by searching for known
 258          * env vars (e.g. KRB5CCNAME) from the PAM environment.
 259          */
 260          return NULL;
 261 }
 262 #endif
 263
 264 /*
 265  * Some platforms, notably Solaris, do not enforce password complexity
 266  * rules during pam_chauthtok() if the real uid of the calling process
 267  * is 0, on the assumption that it's being called by "passwd" run by root.
 268  * This wraps pam_chauthtok and sets/restore the real uid so PAM will do
 269  * the right thing.
 270  */
 271 #ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID
 272 static int
 273 sshpam_chauthtok_ruid(pam_handle_t *pamh, int flags)
 274 {
 275         int result;
 276
 277         if (sshpam_authctxt == NULL)
 278                 fatal("PAM: sshpam_authctxt not initialized");
 279         if (setreuid(sshpam_authctxt->pw->pw_uid, -1) == -1)
 280                 fatal("%s: setreuid failed: %s", __func__, strerror(errno));
 281         result = pam_chauthtok(pamh, flags);
 282         if (setreuid(0, -1) == -1)
 283                 fatal("%s: setreuid failed: %s", __func__, strerror(errno));
 284         return result;
 285 }
 286 # define pam_chauthtok(a,b)     (sshpam_chauthtok_ruid((a), (b)))
 287 #endif
 288
 289 void
 290 sshpam_password_change_required(int reqd)
 291 {
 292         debug3("%s %d", __func__, reqd);
 293         if (sshpam_authctxt == NULL)
 294                 fatal("%s: PAM authctxt not initialized", __func__);
 295         sshpam_authctxt->force_pwchange = reqd;
 296         if (reqd) {
 297                 no_port_forwarding_flag |= 2;
 298                 no_agent_forwarding_flag |= 2;
 299                 no_x11_forwarding_flag |= 2;
 300         } else {
 301                 no_port_forwarding_flag &= ~2;
 302                 no_agent_forwarding_flag &= ~2;
 303                 no_x11_forwarding_flag &= ~2;
 304         }
 305 }
 306
 307 /* Import regular and PAM environment from subprocess */
 308 static void
 309 import_environments(Buffer *b)
 310 {
 311         char *env;
 312         u_int i, num_env;
 313         int err;
 314
 315         debug3("PAM: %s entering", __func__);
 316
 317 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
 318         /* Import variables set by do_pam_account */
 319         sshpam_account_status = buffer_get_int(b);
 320         sshpam_password_change_required(buffer_get_int(b));
 321
 322         /* Import environment from subprocess */
 323         num_env = buffer_get_int(b);
 324         if (num_env > 1024)
 325                 fatal("%s: received %u environment variables, expected <= 1024",
 326                     __func__, num_env);
 327         sshpam_env = xcalloc(num_env + 1, sizeof(*sshpam_env));
 328         debug3("PAM: num env strings %d", num_env);
 329         for(i = 0; i < num_env; i++)
 330                 sshpam_env[i] = buffer_get_string(b, NULL);
 331
 332         sshpam_env[num_env] = NULL;
 333
 334         /* Import PAM environment from subprocess */
 335         num_env = buffer_get_int(b);
 336         debug("PAM: num PAM env strings %d", num_env);
 337         for(i = 0; i < num_env; i++) {
 338                 env = buffer_get_string(b, NULL);
 339
 340 #ifdef HAVE_PAM_PUTENV
 341                 /* Errors are not fatal here */
 342                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 343                         error("PAM: pam_putenv: %s",
 344                             pam_strerror(sshpam_handle, sshpam_err));
 345                 }
 346 #endif
 347         }
 348 #endif
 349 }
 350
 351 /*
 352  * Conversation function for authentication thread.
 353  */
 354 static int
 355 sshpam_thread_conv(int n, sshpam_const struct pam_message **msg,
 356     struct pam_response **resp, void *data)
 357 {
 358         Buffer buffer;
 359         struct pam_ctxt *ctxt;
 360         struct pam_response *reply;
 361         int i;
 362
 363         debug3("PAM: %s entering, %d messages", __func__, n);
 364         *resp = NULL;
 365
 366         if (data == NULL) {
 367                 error("PAM: conversation function passed a null context");
 368                 return (PAM_CONV_ERR);
 369         }
 370         ctxt = data;
 371         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 372                 return (PAM_CONV_ERR);
 373
 374         if ((reply = calloc(n, sizeof(*reply))) == NULL)
 375                 return (PAM_CONV_ERR);
 376
 377         buffer_init(&buffer);
 378         for (i = 0; i < n; ++i) {
 379                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 380                 case PAM_PROMPT_ECHO_OFF:
 381                 case PAM_PROMPT_ECHO_ON:
 382                         buffer_put_cstring(&buffer,
 383                             PAM_MSG_MEMBER(msg, i, msg));
 384                         if (ssh_msg_send(ctxt->pam_csock,
 385                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 386                                 goto fail;
 387                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 388                                 goto fail;
 389                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 390                                 goto fail;
 391                         reply[i].resp = buffer_get_string(&buffer, NULL);
 392                         break;
 393                 case PAM_ERROR_MSG:
 394                 case PAM_TEXT_INFO:
 395                         buffer_put_cstring(&buffer,
 396                             PAM_MSG_MEMBER(msg, i, msg));
 397                         if (ssh_msg_send(ctxt->pam_csock,
 398                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 399                                 goto fail;
 400                         break;
 401                 default:
 402                         goto fail;
 403                 }
 404                 buffer_clear(&buffer);
 405         }
 406         buffer_free(&buffer);
 407         *resp = reply;
 408         return (PAM_SUCCESS);
 409
 410  fail:
 411         for(i = 0; i < n; i++) {
 412                 free(reply[i].resp);
 413         }
 414         free(reply);
 415         buffer_free(&buffer);
 416         return (PAM_CONV_ERR);
 417 }
 418
 419 /*
 420  * Authentication thread.
 421  */
 422 static void *
 423 sshpam_thread(void *ctxtp)
 424 {
 425         struct pam_ctxt *ctxt = ctxtp;
 426         Buffer buffer;
 427         struct pam_conv sshpam_conv;
 428         int flags = (options.permit_empty_passwd == 0 ?
 429             PAM_DISALLOW_NULL_AUTHTOK : 0);
 430 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
 431         extern char **environ;
 432         char **env_from_pam;
 433         u_int i;
 434         const char *pam_user;
 435         const char **ptr_pam_user = &pam_user;
 436         char *tz = getenv("TZ");
 437
 438         sshpam_err = pam_get_item(sshpam_handle, PAM_USER,
 439             (sshpam_const void **)ptr_pam_user);
 440         if (sshpam_err != PAM_SUCCESS)
 441                 goto auth_fail;
 442
 443         environ[0] = NULL;
 444         if (tz != NULL)
 445                 if (setenv("TZ", tz, 1) == -1)
 446                         error("PAM: could not set TZ environment: %s",
 447                             strerror(errno));
 448
 449         if (sshpam_authctxt != NULL) {
 450                 setproctitle("%s [pam]",
 451                     sshpam_authctxt->valid ? pam_user : "unknown");
 452         }
 453 #endif
 454
 455         sshpam_conv.conv = sshpam_thread_conv;
 456         sshpam_conv.appdata_ptr = ctxt;
 457
 458         if (sshpam_authctxt == NULL)
 459                 fatal("%s: PAM authctxt not initialized", __func__);
 460
 461         buffer_init(&buffer);
 462         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 463             (const void *)&sshpam_conv);
 464         if (sshpam_err != PAM_SUCCESS)
 465                 goto auth_fail;
 466         sshpam_err = pam_authenticate(sshpam_handle, flags);
 467         if (sshpam_err == PAM_MAXTRIES)
 468                 sshpam_set_maxtries_reached(1);
 469         if (sshpam_err != PAM_SUCCESS)
 470                 goto auth_fail;
 471
 472         if (compat20) {
 473                 if (!do_pam_account()) {
 474                         sshpam_err = PAM_ACCT_EXPIRED;
 475                         goto auth_fail;
 476                 }
 477                 if (sshpam_authctxt->force_pwchange) {
 478                         sshpam_err = pam_chauthtok(sshpam_handle,
 479                             PAM_CHANGE_EXPIRED_AUTHTOK);
 480                         if (sshpam_err != PAM_SUCCESS)
 481                                 goto auth_fail;
 482                         sshpam_password_change_required(0);
 483                 }
 484         }
 485
 486         buffer_put_cstring(&buffer, "OK");
 487
 488 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
 489         /* Export variables set by do_pam_account */
 490         buffer_put_int(&buffer, sshpam_account_status);
 491         buffer_put_int(&buffer, sshpam_authctxt->force_pwchange);
 492
 493         /* Export any environment strings set in child */
 494         for(i = 0; environ[i] != NULL; i++)
 495                 ; /* Count */
 496         buffer_put_int(&buffer, i);
 497         for(i = 0; environ[i] != NULL; i++)
 498                 buffer_put_cstring(&buffer, environ[i]);
 499
 500         /* Export any environment strings set by PAM in child */
 501         env_from_pam = pam_getenvlist(sshpam_handle);
 502         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 503                 ; /* Count */
 504         buffer_put_int(&buffer, i);
 505         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 506                 buffer_put_cstring(&buffer, env_from_pam[i]);
 507 #endif /* UNSUPPORTED_POSIX_THREADS_HACK */
 508
 509         /* XXX - can't do much about an error here */
 510         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 511         buffer_free(&buffer);
 512         pthread_exit(NULL);
 513
 514  auth_fail:
 515         buffer_put_cstring(&buffer,
 516             pam_strerror(sshpam_handle, sshpam_err));
 517         /* XXX - can't do much about an error here */
 518         if (sshpam_err == PAM_ACCT_EXPIRED)
 519                 ssh_msg_send(ctxt->pam_csock, PAM_ACCT_EXPIRED, &buffer);
 520         else if (sshpam_maxtries_reached)
 521                 ssh_msg_send(ctxt->pam_csock, PAM_MAXTRIES, &buffer);
 522         else
 523                 ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 524         buffer_free(&buffer);
 525         pthread_exit(NULL);
 526
 527         return (NULL); /* Avoid warning for non-pthread case */
 528 }
 529
 530 void
 531 sshpam_thread_cleanup(void)
 532 {
 533         struct pam_ctxt *ctxt = cleanup_ctxt;
 534
 535         debug3("PAM: %s entering", __func__);
 536         if (ctxt != NULL && ctxt->pam_thread != 0) {
 537                 pthread_cancel(ctxt->pam_thread);
 538                 pthread_join(ctxt->pam_thread, NULL);
 539                 close(ctxt->pam_psock);
 540                 close(ctxt->pam_csock);
 541                 memset(ctxt, 0, sizeof(*ctxt));
 542                 cleanup_ctxt = NULL;
 543         }
 544 }
 545
 546 static int
 547 sshpam_null_conv(int n, sshpam_const struct pam_message **msg,
 548     struct pam_response **resp, void *data)
 549 {
 550         debug3("PAM: %s entering, %d messages", __func__, n);
 551         return (PAM_CONV_ERR);
 552 }
 553
 554 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 555
 556 static int
 557 sshpam_store_conv(int n, sshpam_const struct pam_message **msg,
 558     struct pam_response **resp, void *data)
 559 {
 560         struct pam_response *reply;
 561         int i;
 562         size_t len;
 563
 564         debug3("PAM: %s called with %d messages", __func__, n);
 565         *resp = NULL;
 566
 567         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 568                 return (PAM_CONV_ERR);
 569
 570         if ((reply = calloc(n, sizeof(*reply))) == NULL)
 571                 return (PAM_CONV_ERR);
 572
 573         for (i = 0; i < n; ++i) {
 574                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 575                 case PAM_ERROR_MSG:
 576                 case PAM_TEXT_INFO:
 577                         len = strlen(PAM_MSG_MEMBER(msg, i, msg));
 578                         buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
 579                         buffer_append(&loginmsg, "\n", 1 );
 580                         reply[i].resp_retcode = PAM_SUCCESS;
 581                         break;
 582                 default:
 583                         goto fail;
 584                 }
 585         }
 586         *resp = reply;
 587         return (PAM_SUCCESS);
 588
 589  fail:
 590         for(i = 0; i < n; i++) {
 591                 free(reply[i].resp);
 592         }
 593         free(reply);
 594         return (PAM_CONV_ERR);
 595 }
 596
 597 static struct pam_conv store_conv = { sshpam_store_conv, NULL };
 598
 599 void
 600 sshpam_cleanup(void)
 601 {
 602         if (sshpam_handle == NULL || (use_privsep && !mm_is_monitor()))
 603                 return;
 604         debug("PAM: cleanup");
 605         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 606         if (sshpam_session_open) {
 607                 debug("PAM: closing session");
 608                 pam_close_session(sshpam_handle, PAM_SILENT);
 609                 sshpam_session_open = 0;
 610         }
 611         if (sshpam_cred_established) {
 612                 debug("PAM: deleting credentials");
 613                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 614                 sshpam_cred_established = 0;
 615         }
 616         sshpam_authenticated = 0;
 617         pam_end(sshpam_handle, sshpam_err);
 618         sshpam_handle = NULL;
 619 }
 620
 621 static int
 622 sshpam_init(Authctxt *authctxt)
 623 {
 624         const char *pam_rhost, *pam_user, *user = authctxt->user;
 625         const char **ptr_pam_user = &pam_user;
 626         struct ssh *ssh = active_state; /* XXX */
 627
 628         if (sshpam_handle != NULL) {
 629                 /* We already have a PAM context; check if the user matches */
 630                 sshpam_err = pam_get_item(sshpam_handle,
 631                     PAM_USER, (sshpam_const void **)ptr_pam_user);
 632                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 633                         return (0);
 634                 pam_end(sshpam_handle, sshpam_err);
 635                 sshpam_handle = NULL;
 636         }
 637         debug("PAM: initializing for \"%s\"", user);
 638         sshpam_err =
 639             pam_start(SSHD_PAM_SERVICE, user, &store_conv, &sshpam_handle);
 640         sshpam_authctxt = authctxt;
 641
 642         if (sshpam_err != PAM_SUCCESS) {
 643                 pam_end(sshpam_handle, sshpam_err);
 644                 sshpam_handle = NULL;
 645                 return (-1);
 646         }
 647         pam_rhost = auth_get_canonical_hostname(ssh, options.use_dns);
 648         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 649         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 650         if (sshpam_err != PAM_SUCCESS) {
 651                 pam_end(sshpam_handle, sshpam_err);
 652                 sshpam_handle = NULL;
 653                 return (-1);
 654         }
 655 #ifdef PAM_TTY_KLUDGE
 656         /*
 657          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 658          * sshd doesn't set the tty until too late in the auth process and
 659          * may not even set one (for tty-less connections)
 660          */
 661         debug("PAM: setting PAM_TTY to \"ssh\"");
 662         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 663         if (sshpam_err != PAM_SUCCESS) {
 664                 pam_end(sshpam_handle, sshpam_err);
 665                 sshpam_handle = NULL;
 666                 return (-1);
 667         }
 668 #endif
 669         return (0);
 670 }
 671
 672 static void *
 673 sshpam_init_ctx(Authctxt *authctxt)
 674 {
 675         struct pam_ctxt *ctxt;
 676         int socks[2];
 677
 678         debug3("PAM: %s entering", __func__);
 679         /*
 680          * Refuse to start if we don't have PAM enabled or do_pam_account
 681          * has previously failed.
 682          */
 683         if (!options.use_pam || sshpam_account_status == 0)
 684                 return NULL;
 685
 686         /* Initialize PAM */
 687         if (sshpam_init(authctxt) == -1) {
 688                 error("PAM: initialization failed");
 689                 return (NULL);
 690         }
 691
 692         ctxt = xcalloc(1, sizeof *ctxt);
 693
 694         /* Start the authentication thread */
 695         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 696                 error("PAM: failed create sockets: %s", strerror(errno));
 697                 free(ctxt);
 698                 return (NULL);
 699         }
 700         ctxt->pam_psock = socks[0];
 701         ctxt->pam_csock = socks[1];
 702         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 703                 error("PAM: failed to start authentication thread: %s",
 704                     strerror(errno));
 705                 close(socks[0]);
 706                 close(socks[1]);
 707                 free(ctxt);
 708                 return (NULL);
 709         }
 710         cleanup_ctxt = ctxt;
 711         return (ctxt);
 712 }
 713
 714 static int
 715 sshpam_query(void *ctx, char **name, char **info,
 716     u_int *num, char ***prompts, u_int **echo_on)
 717 {
 718         struct ssh *ssh = active_state; /* XXX */
 719         Buffer buffer;
 720         struct pam_ctxt *ctxt = ctx;
 721         size_t plen;
 722         u_char type;
 723         char *msg;
 724         size_t len, mlen;
 725
 726         debug3("PAM: %s entering", __func__);
 727         buffer_init(&buffer);
 728         *name = xstrdup("");
 729         *info = xstrdup("");
 730         *prompts = xmalloc(sizeof(char *));
 731         **prompts = NULL;
 732         plen = 0;
 733         *echo_on = xmalloc(sizeof(u_int));
 734         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 735                 type = buffer_get_char(&buffer);
 736                 msg = buffer_get_string(&buffer, NULL);
 737                 mlen = strlen(msg);
 738                 switch (type) {
 739                 case PAM_PROMPT_ECHO_ON:
 740                 case PAM_PROMPT_ECHO_OFF:
 741                         *num = 1;
 742                         len = plen + mlen + 1;
 743                         **prompts = xreallocarray(**prompts, 1, len);
 744                         strlcpy(**prompts + plen, msg, len - plen);
 745                         plen += mlen;
 746                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 747                         free(msg);
 748                         return (0);
 749                 case PAM_ERROR_MSG:
 750                 case PAM_TEXT_INFO:
 751                         /* accumulate messages */
 752                         len = plen + mlen + 2;
 753                         **prompts = xreallocarray(**prompts, 1, len);
 754                         strlcpy(**prompts + plen, msg, len - plen);
 755                         plen += mlen;
 756                         strlcat(**prompts + plen, "\n", len - plen);
 757                         plen++;
 758                         free(msg);
 759                         break;
 760                 case PAM_ACCT_EXPIRED:
 761                 case PAM_MAXTRIES:
 762                         if (type == PAM_ACCT_EXPIRED)
 763                                 sshpam_account_status = 0;
 764                         if (type == PAM_MAXTRIES)
 765                                 sshpam_set_maxtries_reached(1);
 766                         /* FALLTHROUGH */
 767                 case PAM_AUTH_ERR:
 768                         debug3("PAM: %s", pam_strerror(sshpam_handle, type));
 769                         if (**prompts != NULL && strlen(**prompts) != 0) {
 770                                 *info = **prompts;
 771                                 **prompts = NULL;
 772                                 *num = 0;
 773                                 **echo_on = 0;
 774                                 ctxt->pam_done = -1;
 775                                 free(msg);
 776                                 return 0;
 777                         }
 778                         /* FALLTHROUGH */
 779                 case PAM_SUCCESS:
 780                         if (**prompts != NULL) {
 781                                 /* drain any accumulated messages */
 782                                 debug("PAM: %s", **prompts);
 783                                 buffer_append(&loginmsg, **prompts,
 784                                     strlen(**prompts));
 785                                 free(**prompts);
 786                                 **prompts = NULL;
 787                         }
 788                         if (type == PAM_SUCCESS) {
 789                                 if (!sshpam_authctxt->valid ||
 790                                     (sshpam_authctxt->pw->pw_uid == 0 &&
 791                                     options.permit_root_login != PERMIT_YES))
 792                                         fatal("Internal error: PAM auth "
 793                                             "succeeded when it should have "
 794                                             "failed");
 795                                 import_environments(&buffer);
 796                                 *num = 0;
 797                                 **echo_on = 0;
 798                                 ctxt->pam_done = 1;
 799                                 free(msg);
 800                                 return (0);
 801                         }
 802                         BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
 803                         error("PAM: %s for %s%.100s from %.100s", msg,
 804                             sshpam_authctxt->valid ? "" : "illegal user ",
 805                             sshpam_authctxt->user,
 806                             auth_get_canonical_hostname(ssh, options.use_dns));
 807                         /* FALLTHROUGH */
 808                 default:
 809                         *num = 0;
 810                         **echo_on = 0;
 811                         free(msg);
 812                         ctxt->pam_done = -1;
 813                         return (-1);
 814                 }
 815         }
 816         return (-1);
 817 }
 818
 819 /*
 820  * Returns a junk password of identical length to that the user supplied.
 821  * Used to mitigate timing attacks against crypt(3)/PAM stacks that
 822  * vary processing time in proportion to password length.
 823  */
 824 static char *
 825 fake_password(const char *wire_password)
 826 {
 827         const char junk[] = "\b\n\r\177INCORRECT";
 828         char *ret = NULL;
 829         size_t i, l = wire_password != NULL ? strlen(wire_password) : 0;
 830
 831         if (l >= INT_MAX)
 832                 fatal("%s: password length too long: %zu", __func__, l);
 833
 834         ret = malloc(l + 1);
 835         for (i = 0; i < l; i++)
 836                 ret[i] = junk[i % (sizeof(junk) - 1)];
 837         ret[i] = '\0';
 838         return ret;
 839 }
 840
 841 /* XXX - see also comment in auth-chall.c:verify_response */
 842 static int
 843 sshpam_respond(void *ctx, u_int num, char **resp)
 844 {
 845         Buffer buffer;
 846         struct pam_ctxt *ctxt = ctx;
 847         char *fake;
 848
 849         debug2("PAM: %s entering, %u responses", __func__, num);
 850         switch (ctxt->pam_done) {
 851         case 1:
 852                 sshpam_authenticated = 1;
 853                 return (0);
 854         case 0:
 855                 break;
 856         default:
 857                 return (-1);
 858         }
 859         if (num != 1) {
 860                 error("PAM: expected one response, got %u", num);
 861                 return (-1);
 862         }
 863         buffer_init(&buffer);
 864         if (sshpam_authctxt->valid &&
 865             (sshpam_authctxt->pw->pw_uid != 0 ||
 866             options.permit_root_login == PERMIT_YES))
 867                 buffer_put_cstring(&buffer, *resp);
 868         else {
 869                 fake = fake_password(*resp);
 870                 buffer_put_cstring(&buffer, fake);
 871                 free(fake);
 872         }
 873         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 874                 buffer_free(&buffer);
 875                 return (-1);
 876         }
 877         buffer_free(&buffer);
 878         return (1);
 879 }
 880
 881 static void
 882 sshpam_free_ctx(void *ctxtp)
 883 {
 884         struct pam_ctxt *ctxt = ctxtp;
 885
 886         debug3("PAM: %s entering", __func__);
 887         sshpam_thread_cleanup();
 888         free(ctxt);
 889         /*
 890          * We don't call sshpam_cleanup() here because we may need the PAM
 891          * handle at a later stage, e.g. when setting up a session.  It's
 892          * still on the cleanup list, so pam_end() *will* be called before
 893          * the server process terminates.
 894          */
 895 }
 896
 897 KbdintDevice sshpam_device = {
 898         "pam",
 899         sshpam_init_ctx,
 900         sshpam_query,
 901         sshpam_respond,
 902         sshpam_free_ctx
 903 };
 904
 905 KbdintDevice mm_sshpam_device = {
 906         "pam",
 907         mm_sshpam_init_ctx,
 908         mm_sshpam_query,
 909         mm_sshpam_respond,
 910         mm_sshpam_free_ctx
 911 };
 912
 913 /*
 914  * This replaces auth-pam.c
 915  */
 916 void
 917 start_pam(Authctxt *authctxt)
 918 {
 919         if (!options.use_pam)
 920                 fatal("PAM: initialisation requested when UsePAM=no");
 921
 922         if (sshpam_init(authctxt) == -1)
 923                 fatal("PAM: initialisation failed");
 924 }
 925
 926 void
 927 finish_pam(void)
 928 {
 929         sshpam_cleanup();
 930 }
 931
 932 u_int
 933 do_pam_account(void)
 934 {
 935         debug("%s: called", __func__);
 936         if (sshpam_account_status != -1)
 937                 return (sshpam_account_status);
 938
 939         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 940         debug3("PAM: %s pam_acct_mgmt = %d (%s)", __func__, sshpam_err,
 941             pam_strerror(sshpam_handle, sshpam_err));
 942
 943         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
 944                 sshpam_account_status = 0;
 945                 return (sshpam_account_status);
 946         }
 947
 948         if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
 949                 sshpam_password_change_required(1);
 950
 951         sshpam_account_status = 1;
 952         return (sshpam_account_status);
 953 }
 954
 955 void
 956 do_pam_setcred(int init)
 957 {
 958         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 959             (const void *)&store_conv);
 960         if (sshpam_err != PAM_SUCCESS)
 961                 fatal("PAM: failed to set PAM_CONV: %s",
 962                     pam_strerror(sshpam_handle, sshpam_err));
 963         if (init) {
 964                 debug("PAM: establishing credentials");
 965                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 966         } else {
 967                 debug("PAM: reinitializing credentials");
 968                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 969         }
 970         if (sshpam_err == PAM_SUCCESS) {
 971                 sshpam_cred_established = 1;
 972                 return;
 973         }
 974         if (sshpam_authenticated)
 975                 fatal("PAM: pam_setcred(): %s",
 976                     pam_strerror(sshpam_handle, sshpam_err));
 977         else
 978                 debug("PAM: pam_setcred(): %s",
 979                     pam_strerror(sshpam_handle, sshpam_err));
 980 }
 981
 982 static int
 983 sshpam_tty_conv(int n, sshpam_const struct pam_message **msg,
 984     struct pam_response **resp, void *data)
 985 {
 986         char input[PAM_MAX_MSG_SIZE];
 987         struct pam_response *reply;
 988         int i;
 989
 990         debug3("PAM: %s called with %d messages", __func__, n);
 991
 992         *resp = NULL;
 993
 994         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
 995                 return (PAM_CONV_ERR);
 996
 997         if ((reply = calloc(n, sizeof(*reply))) == NULL)
 998                 return (PAM_CONV_ERR);
 999
1000         for (i = 0; i < n; ++i) {
1001                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
1002                 case PAM_PROMPT_ECHO_OFF:
1003                         reply[i].resp =
1004                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
1005                             RP_ALLOW_STDIN);
1006                         reply[i].resp_retcode = PAM_SUCCESS;
1007                         break;
1008                 case PAM_PROMPT_ECHO_ON:
1009                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
1010                         if (fgets(input, sizeof input, stdin) == NULL)
1011                                 input[0] = '\0';
1012                         if ((reply[i].resp = strdup(input)) == NULL)
1013                                 goto fail;
1014                         reply[i].resp_retcode = PAM_SUCCESS;
1015                         break;
1016                 case PAM_ERROR_MSG:
1017                 case PAM_TEXT_INFO:
1018                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
1019                         reply[i].resp_retcode = PAM_SUCCESS;
1020                         break;
1021                 default:
1022                         goto fail;
1023                 }
1024         }
1025         *resp = reply;
1026         return (PAM_SUCCESS);
1027
1028  fail:
1029         for(i = 0; i < n; i++) {
1030                 free(reply[i].resp);
1031         }
1032         free(reply);
1033         return (PAM_CONV_ERR);
1034 }
1035
1036 static struct pam_conv tty_conv = { sshpam_tty_conv, NULL };
1037
1038 /*
1039  * XXX this should be done in the authentication phase, but ssh1 doesn't
1040  * support that
1041  */
1042 void
1043 do_pam_chauthtok(void)
1044 {
1045         if (use_privsep)
1046                 fatal("Password expired (unable to change with privsep)");
1047         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1048             (const void *)&tty_conv);
1049         if (sshpam_err != PAM_SUCCESS)
1050                 fatal("PAM: failed to set PAM_CONV: %s",
1051                     pam_strerror(sshpam_handle, sshpam_err));
1052         debug("PAM: changing password");
1053         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
1054         if (sshpam_err != PAM_SUCCESS)
1055                 fatal("PAM: pam_chauthtok(): %s",
1056                     pam_strerror(sshpam_handle, sshpam_err));
1057 }
1058
1059 void
1060 do_pam_session(void)
1061 {
1062         debug3("PAM: opening session");
1063         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1064             (const void *)&store_conv);
1065         if (sshpam_err != PAM_SUCCESS)
1066                 fatal("PAM: failed to set PAM_CONV: %s",
1067                     pam_strerror(sshpam_handle, sshpam_err));
1068         sshpam_err = pam_open_session(sshpam_handle, 0);
1069         if (sshpam_err == PAM_SUCCESS)
1070                 sshpam_session_open = 1;
1071         else {
1072                 sshpam_session_open = 0;
1073                 disable_forwarding();
1074                 error("PAM: pam_open_session(): %s",
1075                     pam_strerror(sshpam_handle, sshpam_err));
1076         }
1077
1078 }
1079
1080 int
1081 is_pam_session_open(void)
1082 {
1083         return sshpam_session_open;
1084 }
1085
1086 /*
1087  * Set a PAM environment string. We need to do this so that the session
1088  * modules can handle things like Kerberos/GSI credentials that appear
1089  * during the ssh authentication process.
1090  */
1091 int
1092 do_pam_putenv(char *name, char *value)
1093 {
1094         int ret = 1;
1095 #ifdef HAVE_PAM_PUTENV
1096         char *compound;
1097         size_t len;
1098
1099         len = strlen(name) + strlen(value) + 2;
1100         compound = xmalloc(len);
1101
1102         snprintf(compound, len, "%s=%s", name, value);
1103         ret = pam_putenv(sshpam_handle, compound);
1104         free(compound);
1105 #endif
1106
1107         return (ret);
1108 }
1109
1110 char **
1111 fetch_pam_child_environment(void)
1112 {
1113         return sshpam_env;
1114 }
1115
1116 char **
1117 fetch_pam_environment(void)
1118 {
1119         return (pam_getenvlist(sshpam_handle));
1120 }
1121
1122 void
1123 free_pam_environment(char **env)
1124 {
1125         char **envp;
1126
1127         if (env == NULL)
1128                 return;
1129
1130         for (envp = env; *envp; envp++)
1131                 free(*envp);
1132         free(env);
1133 }
1134
1135 /*
1136  * "Blind" conversation function for password authentication.  Assumes that
1137  * echo-off prompts are for the password and stores messages for later
1138  * display.
1139  */
1140 static int
1141 sshpam_passwd_conv(int n, sshpam_const struct pam_message **msg,
1142     struct pam_response **resp, void *data)
1143 {
1144         struct pam_response *reply;
1145         int i;
1146         size_t len;
1147
1148         debug3("PAM: %s called with %d messages", __func__, n);
1149
1150         *resp = NULL;
1151
1152         if (n <= 0 || n > PAM_MAX_NUM_MSG)
1153                 return (PAM_CONV_ERR);
1154
1155         if ((reply = calloc(n, sizeof(*reply))) == NULL)
1156                 return (PAM_CONV_ERR);
1157
1158         for (i = 0; i < n; ++i) {
1159                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
1160                 case PAM_PROMPT_ECHO_OFF:
1161                         if (sshpam_password == NULL)
1162                                 goto fail;
1163                         if ((reply[i].resp = strdup(sshpam_password)) == NULL)
1164                                 goto fail;
1165                         reply[i].resp_retcode = PAM_SUCCESS;
1166                         break;
1167                 case PAM_ERROR_MSG:
1168                 case PAM_TEXT_INFO:
1169                         len = strlen(PAM_MSG_MEMBER(msg, i, msg));
1170                         if (len > 0) {
1171                                 buffer_append(&loginmsg,
1172                                     PAM_MSG_MEMBER(msg, i, msg), len);
1173                                 buffer_append(&loginmsg, "\n", 1);
1174                         }
1175                         if ((reply[i].resp = strdup("")) == NULL)
1176                                 goto fail;
1177                         reply[i].resp_retcode = PAM_SUCCESS;
1178                         break;
1179                 default:
1180                         goto fail;
1181                 }
1182         }
1183         *resp = reply;
1184         return (PAM_SUCCESS);
1185
1186  fail:
1187         for(i = 0; i < n; i++) {
1188                 free(reply[i].resp);
1189         }
1190         free(reply);
1191         return (PAM_CONV_ERR);
1192 }
1193
1194 static struct pam_conv passwd_conv = { sshpam_passwd_conv, NULL };
1195
1196 /*
1197  * Attempt password authentication via PAM
1198  */
1199 int
1200 sshpam_auth_passwd(Authctxt *authctxt, const char *password)
1201 {
1202         int flags = (options.permit_empty_passwd == 0 ?
1203             PAM_DISALLOW_NULL_AUTHTOK : 0);
1204         char *fake = NULL;
1205
1206         if (!options.use_pam || sshpam_handle == NULL)
1207                 fatal("PAM: %s called when PAM disabled or failed to "
1208                     "initialise.", __func__);
1209
1210         sshpam_password = password;
1211         sshpam_authctxt = authctxt;
1212
1213         /*
1214          * If the user logging in is invalid, or is root but is not permitted
1215          * by PermitRootLogin, use an invalid password to prevent leaking
1216          * information via timing (eg if the PAM config has a delay on fail).
1217          */
1218         if (!authctxt->valid || (authctxt->pw->pw_uid == 0 &&
1219             options.permit_root_login != PERMIT_YES))
1220                 sshpam_password = fake = fake_password(password);
1221
1222         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1223             (const void *)&passwd_conv);
1224         if (sshpam_err != PAM_SUCCESS)
1225                 fatal("PAM: %s: failed to set PAM_CONV: %s", __func__,
1226                     pam_strerror(sshpam_handle, sshpam_err));
1227
1228         sshpam_err = pam_authenticate(sshpam_handle, flags);
1229         sshpam_password = NULL;
1230         free(fake);
1231         if (sshpam_err == PAM_MAXTRIES)
1232                 sshpam_set_maxtries_reached(1);
1233         if (sshpam_err == PAM_SUCCESS && authctxt->valid) {
1234                 debug("PAM: password authentication accepted for %.100s",
1235                     authctxt->user);
1236                 return 1;
1237         } else {
1238                 debug("PAM: password authentication failed for %.100s: %s",
1239                     authctxt->valid ? authctxt->user : "an illegal user",
1240                     pam_strerror(sshpam_handle, sshpam_err));
1241                 return 0;
1242         }
1243 }
1244
1245 int
1246 sshpam_get_maxtries_reached(void)
1247 {
1248         return sshpam_maxtries_reached;
1249 }
1250
1251 void
1252 sshpam_set_maxtries_reached(int reached)
1253 {
1254         if (reached == 0 || sshpam_maxtries_reached)
1255                 return;
1256         sshpam_maxtries_reached = 1;
1257         options.password_authentication = 0;
1258         options.kbd_interactive_authentication = 0;
1259         options.challenge_response_authentication = 0;
1260 }
1261 #endif /* USE_PAM */