auth-pam.c

   1 /*-
   2  * Copyright (c) 2002 Networks Associates Technology, Inc.
   3  * All rights reserved.
   4  *
   5  * This software was developed for the FreeBSD Project by ThinkSec AS and
   6  * NAI Labs, the Security Research Division of Network Associates, Inc.
   7  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
   8  * DARPA CHATS research program.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 /* Based on $FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des Exp $ */
  33 #include "includes.h"
  34 RCSID("$Id$");
  35
  36 #ifdef USE_PAM
  37 #if defined(HAVE_SECURITY_PAM_APPL_H)
  38 #include <security/pam_appl.h>
  39 #elif defined (HAVE_PAM_PAM_APPL_H)
  40 #include <pam/pam_appl.h>
  41 #endif
  42
  43 #include "auth.h"
  44 #include "auth-pam.h"
  45 #include "buffer.h"
  46 #include "bufaux.h"
  47 #include "canohost.h"
  48 #include "log.h"
  49 #include "monitor_wrap.h"
  50 #include "msg.h"
  51 #include "packet.h"
  52 #include "readpass.h"
  53 #include "servconf.h"
  54 #include "ssh2.h"
  55 #include "xmalloc.h"
  56 #include "auth-options.h"
  57
  58 extern ServerOptions options;
  59 extern Buffer loginmsg;
  60 extern int compat20;
  61
  62 #ifdef USE_POSIX_THREADS
  63 #include <pthread.h>
  64 /*
  65  * Avoid namespace clash when *not* using pthreads for systems *with*
  66  * pthreads, which unconditionally define pthread_t via sys/types.h
  67  * (e.g. Linux)
  68  */
  69 typedef pthread_t sp_pthread_t;
  70 #else
  71 typedef pid_t sp_pthread_t;
  72 #endif
  73
  74 struct pam_ctxt {
  75         sp_pthread_t     pam_thread;
  76         int              pam_psock;
  77         int              pam_csock;
  78         int              pam_done;
  79 };
  80
  81 static void sshpam_free_ctx(void *);
  82 static struct pam_ctxt *cleanup_ctxt;
  83
  84 #ifndef USE_POSIX_THREADS
  85 /*
  86  * Simulate threads with processes.
  87  */
  88
  89 static int sshpam_thread_status = -1;
  90 static mysig_t sshpam_oldsig;
  91
  92 static void
  93 sshpam_sigchld_handler(int sig)
  94 {
  95         if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0) == -1)
  96                 return; /* couldn't wait for process */
  97         if (WIFSIGNALED(sshpam_thread_status) &&
  98             WTERMSIG(sshpam_thread_status) == SIGTERM)
  99                 return; /* terminated by pthread_cancel */
 100         if (!WIFEXITED(sshpam_thread_status))
 101                 fatal("PAM: authentication thread exited unexpectedly");
 102         if (WEXITSTATUS(sshpam_thread_status) != 0)
 103                 fatal("PAM: authentication thread exited uncleanly");
 104 }
 105
 106 static void
 107 pthread_exit(void *value __unused)
 108 {
 109         _exit(0);
 110 }
 111
 112 static int
 113 pthread_create(sp_pthread_t *thread, const void *attr __unused,
 114     void *(*thread_start)(void *), void *arg)
 115 {
 116         pid_t pid;
 117
 118         switch ((pid = fork())) {
 119         case -1:
 120                 error("fork(): %s", strerror(errno));
 121                 return (-1);
 122         case 0:
 123                 thread_start(arg);
 124                 _exit(1);
 125         default:
 126                 *thread = pid;
 127                 sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
 128                 return (0);
 129         }
 130 }
 131
 132 static int
 133 pthread_cancel(sp_pthread_t thread)
 134 {
 135         return (kill(thread, SIGTERM));
 136 }
 137
 138 static int
 139 pthread_join(sp_pthread_t thread, void **value __unused)
 140 {
 141         int status;
 142
 143         if (sshpam_thread_status != -1)
 144                 return (sshpam_thread_status);
 145         signal(SIGCHLD, sshpam_oldsig);
 146         waitpid(thread, &status, 0);
 147         return (status);
 148 }
 149 #endif
 150
 151
 152 static pam_handle_t *sshpam_handle = NULL;
 153 static int sshpam_err = 0;
 154 static int sshpam_authenticated = 0;
 155 static int sshpam_new_authtok_reqd = 0;
 156 static int sshpam_session_open = 0;
 157 static int sshpam_cred_established = 0;
 158 static int sshpam_account_status = -1;
 159 static char **sshpam_env = NULL;
 160
 161 /* Some PAM implementations don't implement this */
 162 #ifndef HAVE_PAM_GETENVLIST
 163 static char **
 164 pam_getenvlist(pam_handle_t *pamh)
 165 {
 166         /*
 167          * XXX - If necessary, we can still support envrionment passing
 168          * for platforms without pam_getenvlist by searching for known
 169          * env vars (e.g. KRB5CCNAME) from the PAM environment.
 170          */
 171          return NULL;
 172 }
 173 #endif
 174
 175 void
 176 pam_password_change_required(int reqd)
 177 {
 178         sshpam_new_authtok_reqd = reqd;
 179         if (reqd) {
 180                 no_port_forwarding_flag |= 2;
 181                 no_agent_forwarding_flag |= 2;
 182                 no_x11_forwarding_flag |= 2;
 183         } else {
 184                 no_port_forwarding_flag &= ~2;
 185                 no_agent_forwarding_flag &= ~2;
 186                 no_x11_forwarding_flag &= ~2;
 187
 188         }
 189 }
 190 /* Import regular and PAM environment from subprocess */
 191 static void
 192 import_environments(Buffer *b)
 193 {
 194         char *env;
 195         u_int i, num_env;
 196         int err;
 197
 198         /* Import variables set by do_pam_account */
 199         sshpam_account_status = buffer_get_int(b);
 200         pam_password_change_required(buffer_get_int(b));
 201
 202         /* Import environment from subprocess */
 203         num_env = buffer_get_int(b);
 204         sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
 205         debug3("PAM: num env strings %d", num_env);
 206         for(i = 0; i < num_env; i++)
 207                 sshpam_env[i] = buffer_get_string(b, NULL);
 208
 209         sshpam_env[num_env] = NULL;
 210
 211         /* Import PAM environment from subprocess */
 212         num_env = buffer_get_int(b);
 213         debug("PAM: num PAM env strings %d", num_env);
 214         for(i = 0; i < num_env; i++) {
 215                 env = buffer_get_string(b, NULL);
 216
 217 #ifdef HAVE_PAM_PUTENV
 218                 /* Errors are not fatal here */
 219                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 220                         error("PAM: pam_putenv: %s",
 221                             pam_strerror(sshpam_handle, sshpam_err));
 222                 }
 223 #endif
 224         }
 225 }
 226
 227 /*
 228  * Conversation function for authentication thread.
 229  */
 230 static int
 231 sshpam_thread_conv(int n, const struct pam_message **msg,
 232     struct pam_response **resp, void *data)
 233 {
 234         Buffer buffer;
 235         struct pam_ctxt *ctxt;
 236         struct pam_response *reply;
 237         int i;
 238
 239         *resp = NULL;
 240
 241         ctxt = data;
 242         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 243                 return (PAM_CONV_ERR);
 244
 245         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 246                 return (PAM_CONV_ERR);
 247         memset(reply, 0, n * sizeof(*reply));
 248
 249         buffer_init(&buffer);
 250         for (i = 0; i < n; ++i) {
 251                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 252                 case PAM_PROMPT_ECHO_OFF:
 253                         buffer_put_cstring(&buffer,
 254                             PAM_MSG_MEMBER(msg, i, msg));
 255                         if (ssh_msg_send(ctxt->pam_csock,
 256                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 257                                 goto fail;
 258                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 259                                 goto fail;
 260                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 261                                 goto fail;
 262                         reply[i].resp = buffer_get_string(&buffer, NULL);
 263                         break;
 264                 case PAM_PROMPT_ECHO_ON:
 265                         buffer_put_cstring(&buffer,
 266                             PAM_MSG_MEMBER(msg, i, msg));
 267                         if (ssh_msg_send(ctxt->pam_csock,
 268                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 269                                 goto fail;
 270                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 271                                 goto fail;
 272                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 273                                 goto fail;
 274                         reply[i].resp = buffer_get_string(&buffer, NULL);
 275                         break;
 276                 case PAM_ERROR_MSG:
 277                         buffer_put_cstring(&buffer,
 278                             PAM_MSG_MEMBER(msg, i, msg));
 279                         if (ssh_msg_send(ctxt->pam_csock,
 280                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 281                                 goto fail;
 282                         break;
 283                 case PAM_TEXT_INFO:
 284                         buffer_put_cstring(&buffer,
 285                             PAM_MSG_MEMBER(msg, i, msg));
 286                         if (ssh_msg_send(ctxt->pam_csock,
 287                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 288                                 goto fail;
 289                         break;
 290                 default:
 291                         goto fail;
 292                 }
 293                 buffer_clear(&buffer);
 294         }
 295         buffer_free(&buffer);
 296         *resp = reply;
 297         return (PAM_SUCCESS);
 298
 299  fail:
 300         for(i = 0; i < n; i++) {
 301                 if (reply[i].resp != NULL)
 302                         xfree(reply[i].resp);
 303         }
 304         xfree(reply);
 305         buffer_free(&buffer);
 306         return (PAM_CONV_ERR);
 307 }
 308
 309 /*
 310  * Authentication thread.
 311  */
 312 static void *
 313 sshpam_thread(void *ctxtp)
 314 {
 315         struct pam_ctxt *ctxt = ctxtp;
 316         Buffer buffer;
 317         struct pam_conv sshpam_conv;
 318 #ifndef USE_POSIX_THREADS
 319         extern char **environ;
 320         char **env_from_pam;
 321         u_int i;
 322         const char *pam_user;
 323
 324         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 325         setproctitle("%s [pam]", pam_user);
 326         environ[0] = NULL;
 327 #endif
 328
 329         sshpam_conv.conv = sshpam_thread_conv;
 330         sshpam_conv.appdata_ptr = ctxt;
 331
 332         buffer_init(&buffer);
 333         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 334             (const void *)&sshpam_conv);
 335         if (sshpam_err != PAM_SUCCESS)
 336                 goto auth_fail;
 337         sshpam_err = pam_authenticate(sshpam_handle, 0);
 338         if (sshpam_err != PAM_SUCCESS)
 339                 goto auth_fail;
 340
 341         if (compat20) {
 342                 if (!do_pam_account())
 343                         goto auth_fail;
 344                 if (sshpam_new_authtok_reqd) {
 345                         sshpam_err = pam_chauthtok(sshpam_handle,
 346                             PAM_CHANGE_EXPIRED_AUTHTOK);
 347                         if (sshpam_err != PAM_SUCCESS)
 348                                 goto auth_fail;
 349                         pam_password_change_required(0);
 350                 }
 351         }
 352
 353         buffer_put_cstring(&buffer, "OK");
 354
 355 #ifndef USE_POSIX_THREADS
 356         /* Export variables set by do_pam_account */
 357         buffer_put_int(&buffer, sshpam_account_status);
 358         buffer_put_int(&buffer, sshpam_new_authtok_reqd);
 359
 360         /* Export any environment strings set in child */
 361         for(i = 0; environ[i] != NULL; i++)
 362                 ; /* Count */
 363         buffer_put_int(&buffer, i);
 364         for(i = 0; environ[i] != NULL; i++)
 365                 buffer_put_cstring(&buffer, environ[i]);
 366
 367         /* Export any environment strings set by PAM in child */
 368         env_from_pam = pam_getenvlist(sshpam_handle);
 369         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 370                 ; /* Count */
 371         buffer_put_int(&buffer, i);
 372         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 373                 buffer_put_cstring(&buffer, env_from_pam[i]);
 374 #endif /* USE_POSIX_THREADS */
 375
 376         /* XXX - can't do much about an error here */
 377         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 378         buffer_free(&buffer);
 379         pthread_exit(NULL);
 380
 381  auth_fail:
 382         buffer_put_cstring(&buffer,
 383             pam_strerror(sshpam_handle, sshpam_err));
 384         /* XXX - can't do much about an error here */
 385         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 386         buffer_free(&buffer);
 387         pthread_exit(NULL);
 388
 389         return (NULL); /* Avoid warning for non-pthread case */
 390 }
 391
 392 void
 393 sshpam_thread_cleanup(void)
 394 {
 395         struct pam_ctxt *ctxt = cleanup_ctxt;
 396
 397         if (ctxt != NULL && ctxt->pam_thread != 0) {
 398                 pthread_cancel(ctxt->pam_thread);
 399                 pthread_join(ctxt->pam_thread, NULL);
 400                 close(ctxt->pam_psock);
 401                 close(ctxt->pam_csock);
 402                 memset(ctxt, 0, sizeof(*ctxt));
 403                 cleanup_ctxt = NULL;
 404         }
 405 }
 406
 407 static int
 408 sshpam_null_conv(int n, const struct pam_message **msg,
 409     struct pam_response **resp, void *data)
 410 {
 411         return (PAM_CONV_ERR);
 412 }
 413
 414 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 415
 416 void
 417 sshpam_cleanup(void)
 418 {
 419         debug("PAM: cleanup");
 420         if (sshpam_handle == NULL)
 421                 return;
 422         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 423         if (sshpam_cred_established) {
 424                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 425                 sshpam_cred_established = 0;
 426         }
 427         if (sshpam_session_open) {
 428                 pam_close_session(sshpam_handle, PAM_SILENT);
 429                 sshpam_session_open = 0;
 430         }
 431         sshpam_authenticated = sshpam_new_authtok_reqd = 0;
 432         pam_end(sshpam_handle, sshpam_err);
 433         sshpam_handle = NULL;
 434 }
 435
 436 static int
 437 sshpam_init(const char *user)
 438 {
 439         extern u_int utmp_len;
 440         extern char *__progname;
 441         const char *pam_rhost, *pam_user;
 442
 443         if (sshpam_handle != NULL) {
 444                 /* We already have a PAM context; check if the user matches */
 445                 sshpam_err = pam_get_item(sshpam_handle,
 446                     PAM_USER, (const void **)&pam_user);
 447                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 448                         return (0);
 449                 pam_end(sshpam_handle, sshpam_err);
 450                 sshpam_handle = NULL;
 451         }
 452         debug("PAM: initializing for \"%s\"", user);
 453         sshpam_err =
 454             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 455         if (sshpam_err != PAM_SUCCESS) {
 456                 pam_end(sshpam_handle, sshpam_err);
 457                 sshpam_handle = NULL;
 458                 return (-1);
 459         }
 460         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 461         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 462         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 463         if (sshpam_err != PAM_SUCCESS) {
 464                 pam_end(sshpam_handle, sshpam_err);
 465                 sshpam_handle = NULL;
 466                 return (-1);
 467         }
 468 #ifdef PAM_TTY_KLUDGE
 469         /*
 470          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 471          * sshd doesn't set the tty until too late in the auth process and
 472          * may not even set one (for tty-less connections)
 473          */
 474         debug("PAM: setting PAM_TTY to \"ssh\"");
 475         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 476         if (sshpam_err != PAM_SUCCESS) {
 477                 pam_end(sshpam_handle, sshpam_err);
 478                 sshpam_handle = NULL;
 479                 return (-1);
 480         }
 481 #endif
 482         return (0);
 483 }
 484
 485 static void *
 486 sshpam_init_ctx(Authctxt *authctxt)
 487 {
 488         struct pam_ctxt *ctxt;
 489         int socks[2];
 490
 491         /* Refuse to start if we don't have PAM enabled */
 492         if (!options.use_pam)
 493                 return NULL;
 494
 495         /* Initialize PAM */
 496         if (sshpam_init(authctxt->user) == -1) {
 497                 error("PAM: initialization failed");
 498                 return (NULL);
 499         }
 500
 501         ctxt = xmalloc(sizeof *ctxt);
 502         memset(ctxt, 0, sizeof(*ctxt));
 503
 504         /* Start the authentication thread */
 505         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 506                 error("PAM: failed create sockets: %s", strerror(errno));
 507                 xfree(ctxt);
 508                 return (NULL);
 509         }
 510         ctxt->pam_psock = socks[0];
 511         ctxt->pam_csock = socks[1];
 512         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 513                 error("PAM: failed to start authentication thread: %s",
 514                     strerror(errno));
 515                 close(socks[0]);
 516                 close(socks[1]);
 517                 xfree(ctxt);
 518                 return (NULL);
 519         }
 520         cleanup_ctxt = ctxt;
 521         return (ctxt);
 522 }
 523
 524 static int
 525 sshpam_query(void *ctx, char **name, char **info,
 526     u_int *num, char ***prompts, u_int **echo_on)
 527 {
 528         Buffer buffer;
 529         struct pam_ctxt *ctxt = ctx;
 530         size_t plen;
 531         u_char type;
 532         char *msg;
 533         size_t len;
 534
 535         buffer_init(&buffer);
 536         *name = xstrdup("");
 537         *info = xstrdup("");
 538         *prompts = xmalloc(sizeof(char *));
 539         **prompts = NULL;
 540         plen = 0;
 541         *echo_on = xmalloc(sizeof(u_int));
 542         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 543                 type = buffer_get_char(&buffer);
 544                 msg = buffer_get_string(&buffer, NULL);
 545                 switch (type) {
 546                 case PAM_PROMPT_ECHO_ON:
 547                 case PAM_PROMPT_ECHO_OFF:
 548                         *num = 1;
 549                         len = plen + strlen(msg) + 1;
 550                         **prompts = xrealloc(**prompts, len);
 551                         plen += snprintf(**prompts + plen, len, "%s", msg);
 552                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 553                         xfree(msg);
 554                         return (0);
 555                 case PAM_ERROR_MSG:
 556                 case PAM_TEXT_INFO:
 557                         /* accumulate messages */
 558                         len = plen + strlen(msg) + 2;
 559                         **prompts = xrealloc(**prompts, len);
 560                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 561                         xfree(msg);
 562                         break;
 563                 case PAM_SUCCESS:
 564                 case PAM_AUTH_ERR:
 565                         if (**prompts != NULL) {
 566                                 /* drain any accumulated messages */
 567                                 debug("PAM: %s", **prompts);
 568                                 buffer_append(&loginmsg, **prompts,
 569                                     strlen(**prompts));
 570                                 xfree(**prompts);
 571                                 **prompts = NULL;
 572                         }
 573                         if (type == PAM_SUCCESS) {
 574                                 import_environments(&buffer);
 575                                 *num = 0;
 576                                 **echo_on = 0;
 577                                 ctxt->pam_done = 1;
 578                                 xfree(msg);
 579                                 return (0);
 580                         }
 581                         error("PAM: %s", msg);
 582                         /* FALLTHROUGH */
 583                 default:
 584                         *num = 0;
 585                         **echo_on = 0;
 586                         xfree(msg);
 587                         ctxt->pam_done = -1;
 588                         return (-1);
 589                 }
 590         }
 591         return (-1);
 592 }
 593
 594 /* XXX - see also comment in auth-chall.c:verify_response */
 595 static int
 596 sshpam_respond(void *ctx, u_int num, char **resp)
 597 {
 598         Buffer buffer;
 599         struct pam_ctxt *ctxt = ctx;
 600
 601         debug2("PAM: %s", __func__);
 602         switch (ctxt->pam_done) {
 603         case 1:
 604                 sshpam_authenticated = 1;
 605                 return (0);
 606         case 0:
 607                 break;
 608         default:
 609                 return (-1);
 610         }
 611         if (num != 1) {
 612                 error("PAM: expected one response, got %u", num);
 613                 return (-1);
 614         }
 615         buffer_init(&buffer);
 616         buffer_put_cstring(&buffer, *resp);
 617         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 618                 buffer_free(&buffer);
 619                 return (-1);
 620         }
 621         buffer_free(&buffer);
 622         return (1);
 623 }
 624
 625 static void
 626 sshpam_free_ctx(void *ctxtp)
 627 {
 628         struct pam_ctxt *ctxt = ctxtp;
 629
 630         sshpam_thread_cleanup();
 631         xfree(ctxt);
 632         /*
 633          * We don't call sshpam_cleanup() here because we may need the PAM
 634          * handle at a later stage, e.g. when setting up a session.  It's
 635          * still on the cleanup list, so pam_end() *will* be called before
 636          * the server process terminates.
 637          */
 638 }
 639
 640 KbdintDevice sshpam_device = {
 641         "pam",
 642         sshpam_init_ctx,
 643         sshpam_query,
 644         sshpam_respond,
 645         sshpam_free_ctx
 646 };
 647
 648 KbdintDevice mm_sshpam_device = {
 649         "pam",
 650         mm_sshpam_init_ctx,
 651         mm_sshpam_query,
 652         mm_sshpam_respond,
 653         mm_sshpam_free_ctx
 654 };
 655
 656 /*
 657  * This replaces auth-pam.c
 658  */
 659 void
 660 start_pam(const char *user)
 661 {
 662         if (!options.use_pam)
 663                 fatal("PAM: initialisation requested when UsePAM=no");
 664
 665         if (sshpam_init(user) == -1)
 666                 fatal("PAM: initialisation failed");
 667 }
 668
 669 void
 670 finish_pam(void)
 671 {
 672         sshpam_cleanup();
 673 }
 674
 675 u_int
 676 do_pam_account(void)
 677 {
 678         if (sshpam_account_status != -1)
 679                 return (sshpam_account_status);
 680
 681         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 682         debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);
 683
 684         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
 685                 sshpam_account_status = 0;
 686                 return (sshpam_account_status);
 687         }
 688
 689         if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
 690                 pam_password_change_required(1);
 691
 692         sshpam_account_status = 1;
 693         return (sshpam_account_status);
 694 }
 695
 696 void
 697 do_pam_set_tty(const char *tty)
 698 {
 699         if (tty != NULL) {
 700                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 701                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 702                 if (sshpam_err != PAM_SUCCESS)
 703                         fatal("PAM: failed to set PAM_TTY: %s",
 704                             pam_strerror(sshpam_handle, sshpam_err));
 705         }
 706 }
 707
 708 void
 709 do_pam_setcred(int init)
 710 {
 711         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 712             (const void *)&null_conv);
 713         if (sshpam_err != PAM_SUCCESS)
 714                 fatal("PAM: failed to set PAM_CONV: %s",
 715                     pam_strerror(sshpam_handle, sshpam_err));
 716         if (init) {
 717                 debug("PAM: establishing credentials");
 718                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 719         } else {
 720                 debug("PAM: reinitializing credentials");
 721                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 722         }
 723         if (sshpam_err == PAM_SUCCESS) {
 724                 sshpam_cred_established = 1;
 725                 return;
 726         }
 727         if (sshpam_authenticated)
 728                 fatal("PAM: pam_setcred(): %s",
 729                     pam_strerror(sshpam_handle, sshpam_err));
 730         else
 731                 debug("PAM: pam_setcred(): %s",
 732                     pam_strerror(sshpam_handle, sshpam_err));
 733 }
 734
 735 int
 736 is_pam_password_change_required(void)
 737 {
 738         return (sshpam_new_authtok_reqd);
 739 }
 740
 741 static int
 742 pam_tty_conv(int n, const struct pam_message **msg,
 743     struct pam_response **resp, void *data)
 744 {
 745         char input[PAM_MAX_MSG_SIZE];
 746         struct pam_response *reply;
 747         int i;
 748
 749         *resp = NULL;
 750
 751         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
 752                 return (PAM_CONV_ERR);
 753
 754         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 755                 return (PAM_CONV_ERR);
 756         memset(reply, 0, n * sizeof(*reply));
 757
 758         for (i = 0; i < n; ++i) {
 759                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 760                 case PAM_PROMPT_ECHO_OFF:
 761                         reply[i].resp =
 762                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 763                             RP_ALLOW_STDIN);
 764                         reply[i].resp_retcode = PAM_SUCCESS;
 765                         break;
 766                 case PAM_PROMPT_ECHO_ON:
 767                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 768                         fgets(input, sizeof input, stdin);
 769                         reply[i].resp = xstrdup(input);
 770                         reply[i].resp_retcode = PAM_SUCCESS;
 771                         break;
 772                 case PAM_ERROR_MSG:
 773                 case PAM_TEXT_INFO:
 774                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 775                         reply[i].resp_retcode = PAM_SUCCESS;
 776                         break;
 777                 default:
 778                         goto fail;
 779                 }
 780         }
 781         *resp = reply;
 782         return (PAM_SUCCESS);
 783
 784  fail:
 785         for(i = 0; i < n; i++) {
 786                 if (reply[i].resp != NULL)
 787                         xfree(reply[i].resp);
 788         }
 789         xfree(reply);
 790         return (PAM_CONV_ERR);
 791 }
 792
 793 static struct pam_conv tty_conv = { pam_tty_conv, NULL };
 794
 795 /*
 796  * XXX this should be done in the authentication phase, but ssh1 doesn't
 797  * support that
 798  */
 799 void
 800 do_pam_chauthtok(void)
 801 {
 802         if (use_privsep)
 803                 fatal("Password expired (unable to change with privsep)");
 804         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 805             (const void *)&tty_conv);
 806         if (sshpam_err != PAM_SUCCESS)
 807                 fatal("PAM: failed to set PAM_CONV: %s",
 808                     pam_strerror(sshpam_handle, sshpam_err));
 809         debug("PAM: changing password");
 810         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 811         if (sshpam_err != PAM_SUCCESS)
 812                 fatal("PAM: pam_chauthtok(): %s",
 813                     pam_strerror(sshpam_handle, sshpam_err));
 814 }
 815
 816 void
 817 do_pam_session(void)
 818 {
 819         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 820             (const void *)&tty_conv);
 821         if (sshpam_err != PAM_SUCCESS)
 822                 fatal("PAM: failed to set PAM_CONV: %s",
 823                     pam_strerror(sshpam_handle, sshpam_err));
 824         sshpam_err = pam_open_session(sshpam_handle, 0);
 825         if (sshpam_err != PAM_SUCCESS)
 826                 fatal("PAM: pam_open_session(): %s",
 827                     pam_strerror(sshpam_handle, sshpam_err));
 828         sshpam_session_open = 1;
 829 }
 830
 831 /*
 832  * Set a PAM environment string. We need to do this so that the session
 833  * modules can handle things like Kerberos/GSI credentials that appear
 834  * during the ssh authentication process.
 835  */
 836 int
 837 do_pam_putenv(char *name, char *value)
 838 {
 839         int ret = 1;
 840 #ifdef HAVE_PAM_PUTENV
 841         char *compound;
 842         size_t len;
 843
 844         len = strlen(name) + strlen(value) + 2;
 845         compound = xmalloc(len);
 846
 847         snprintf(compound, len, "%s=%s", name, value);
 848         ret = pam_putenv(sshpam_handle, compound);
 849         xfree(compound);
 850 #endif
 851
 852         return (ret);
 853 }
 854
 855 void
 856 print_pam_messages(void)
 857 {
 858         /* XXX */
 859 }
 860
 861 char **
 862 fetch_pam_child_environment(void)
 863 {
 864         return sshpam_env;
 865 }
 866
 867 char **
 868 fetch_pam_environment(void)
 869 {
 870         return (pam_getenvlist(sshpam_handle));
 871 }
 872
 873 void
 874 free_pam_environment(char **env)
 875 {
 876         char **envp;
 877
 878         if (env == NULL)
 879                 return;
 880
 881         for (envp = env; *envp; envp++)
 882                 xfree(*envp);
 883         xfree(env);
 884 }
 885
 886 #endif /* USE_PAM */