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 "misc.h"
  53 #include "servconf.h"
  54 #include "ssh2.h"
  55 #include "xmalloc.h"
  56 #include "auth-options.h"
  57
  58 extern ServerOptions options;
  59 extern Buffer loginmsg;
  60 extern int compat20;
  61 extern u_int utmp_len;
  62
  63 #ifdef USE_POSIX_THREADS
  64 #include <pthread.h>
  65 /*
  66  * Avoid namespace clash when *not* using pthreads for systems *with*
  67  * pthreads, which unconditionally define pthread_t via sys/types.h
  68  * (e.g. Linux)
  69  */
  70 typedef pthread_t sp_pthread_t;
  71 #else
  72 typedef pid_t sp_pthread_t;
  73 #endif
  74
  75 struct pam_ctxt {
  76         sp_pthread_t     pam_thread;
  77         int              pam_psock;
  78         int              pam_csock;
  79         int              pam_done;
  80 };
  81
  82 static void sshpam_free_ctx(void *);
  83 static struct pam_ctxt *cleanup_ctxt;
  84
  85 #ifndef USE_POSIX_THREADS
  86 /*
  87  * Simulate threads with processes.
  88  */
  89
  90 static int sshpam_thread_status = -1;
  91 static mysig_t sshpam_oldsig;
  92
  93 static void
  94 sshpam_sigchld_handler(int sig)
  95 {
  96         signal(SIGCHLD, SIG_DFL);
  97         if (cleanup_ctxt == NULL)
  98                 return; /* handler called after PAM cleanup, shouldn't happen */
  99         if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG)
 100              == -1) {
 101                 /* PAM thread has not exitted, privsep slave must have */
 102                 kill(cleanup_ctxt->pam_thread, SIGTERM);
 103                 if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0)
 104                     == -1)
 105                         return; /* could not wait */
 106         }
 107         if (WIFSIGNALED(sshpam_thread_status) &&
 108             WTERMSIG(sshpam_thread_status) == SIGTERM)
 109                 return; /* terminated by pthread_cancel */
 110         if (!WIFEXITED(sshpam_thread_status))
 111                 fatal("PAM: authentication thread exited unexpectedly");
 112         if (WEXITSTATUS(sshpam_thread_status) != 0)
 113                 fatal("PAM: authentication thread exited uncleanly");
 114 }
 115
 116 static void
 117 pthread_exit(void *value __unused)
 118 {
 119         _exit(0);
 120 }
 121
 122 static int
 123 pthread_create(sp_pthread_t *thread, const void *attr __unused,
 124     void *(*thread_start)(void *), void *arg)
 125 {
 126         pid_t pid;
 127
 128         sshpam_thread_status = -1;
 129         switch ((pid = fork())) {
 130         case -1:
 131                 error("fork(): %s", strerror(errno));
 132                 return (-1);
 133         case 0:
 134                 thread_start(arg);
 135                 _exit(1);
 136         default:
 137                 *thread = pid;
 138                 sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
 139                 return (0);
 140         }
 141 }
 142
 143 static int
 144 pthread_cancel(sp_pthread_t thread)
 145 {
 146         signal(SIGCHLD, sshpam_oldsig);
 147         return (kill(thread, SIGTERM));
 148 }
 149
 150 static int
 151 pthread_join(sp_pthread_t thread, void **value __unused)
 152 {
 153         int status;
 154
 155         if (sshpam_thread_status != -1)
 156                 return (sshpam_thread_status);
 157         signal(SIGCHLD, sshpam_oldsig);
 158         waitpid(thread, &status, 0);
 159         return (status);
 160 }
 161 #endif
 162
 163
 164 static pam_handle_t *sshpam_handle = NULL;
 165 static int sshpam_err = 0;
 166 static int sshpam_authenticated = 0;
 167 static int sshpam_session_open = 0;
 168 static int sshpam_cred_established = 0;
 169 static int sshpam_account_status = -1;
 170 static char **sshpam_env = NULL;
 171 static Authctxt *sshpam_authctxt = NULL;
 172
 173 /* Some PAM implementations don't implement this */
 174 #ifndef HAVE_PAM_GETENVLIST
 175 static char **
 176 pam_getenvlist(pam_handle_t *pamh)
 177 {
 178         /*
 179          * XXX - If necessary, we can still support envrionment passing
 180          * for platforms without pam_getenvlist by searching for known
 181          * env vars (e.g. KRB5CCNAME) from the PAM environment.
 182          */
 183          return NULL;
 184 }
 185 #endif
 186
 187 void
 188 pam_password_change_required(int reqd)
 189 {
 190         debug3("%s %d", __func__, reqd);
 191         if (sshpam_authctxt == NULL)
 192                 fatal("%s: PAM authctxt not initialized", __func__);
 193         sshpam_authctxt->force_pwchange = reqd;
 194         if (reqd) {
 195                 no_port_forwarding_flag |= 2;
 196                 no_agent_forwarding_flag |= 2;
 197                 no_x11_forwarding_flag |= 2;
 198         } else {
 199                 no_port_forwarding_flag &= ~2;
 200                 no_agent_forwarding_flag &= ~2;
 201                 no_x11_forwarding_flag &= ~2;
 202         }
 203 }
 204
 205 /* Import regular and PAM environment from subprocess */
 206 static void
 207 import_environments(Buffer *b)
 208 {
 209         char *env;
 210         u_int i, num_env;
 211         int err;
 212
 213         debug3("PAM: %s entering", __func__);
 214
 215 #ifndef USE_POSIX_THREADS
 216         /* Import variables set by do_pam_account */
 217         sshpam_account_status = buffer_get_int(b);
 218         pam_password_change_required(buffer_get_int(b));
 219
 220         /* Import environment from subprocess */
 221         num_env = buffer_get_int(b);
 222         sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
 223         debug3("PAM: num env strings %d", num_env);
 224         for(i = 0; i < num_env; i++)
 225                 sshpam_env[i] = buffer_get_string(b, NULL);
 226
 227         sshpam_env[num_env] = NULL;
 228
 229         /* Import PAM environment from subprocess */
 230         num_env = buffer_get_int(b);
 231         debug("PAM: num PAM env strings %d", num_env);
 232         for(i = 0; i < num_env; i++) {
 233                 env = buffer_get_string(b, NULL);
 234
 235 #ifdef HAVE_PAM_PUTENV
 236                 /* Errors are not fatal here */
 237                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 238                         error("PAM: pam_putenv: %s",
 239                             pam_strerror(sshpam_handle, sshpam_err));
 240                 }
 241 #endif
 242         }
 243 #endif
 244 }
 245
 246 /*
 247  * Conversation function for authentication thread.
 248  */
 249 static int
 250 sshpam_thread_conv(int n, const struct pam_message **msg,
 251     struct pam_response **resp, void *data)
 252 {
 253         Buffer buffer;
 254         struct pam_ctxt *ctxt;
 255         struct pam_response *reply;
 256         int i;
 257
 258         debug3("PAM: %s entering, %d messages", __func__, n);
 259         *resp = NULL;
 260
 261         ctxt = data;
 262         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 263                 return (PAM_CONV_ERR);
 264
 265         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 266                 return (PAM_CONV_ERR);
 267         memset(reply, 0, n * sizeof(*reply));
 268
 269         buffer_init(&buffer);
 270         for (i = 0; i < n; ++i) {
 271                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 272                 case PAM_PROMPT_ECHO_OFF:
 273                         buffer_put_cstring(&buffer,
 274                             PAM_MSG_MEMBER(msg, i, msg));
 275                         if (ssh_msg_send(ctxt->pam_csock,
 276                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 277                                 goto fail;
 278                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 279                                 goto fail;
 280                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 281                                 goto fail;
 282                         reply[i].resp = buffer_get_string(&buffer, NULL);
 283                         break;
 284                 case PAM_PROMPT_ECHO_ON:
 285                         buffer_put_cstring(&buffer,
 286                             PAM_MSG_MEMBER(msg, i, msg));
 287                         if (ssh_msg_send(ctxt->pam_csock,
 288                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 289                                 goto fail;
 290                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 291                                 goto fail;
 292                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 293                                 goto fail;
 294                         reply[i].resp = buffer_get_string(&buffer, NULL);
 295                         break;
 296                 case PAM_ERROR_MSG:
 297                         buffer_put_cstring(&buffer,
 298                             PAM_MSG_MEMBER(msg, i, msg));
 299                         if (ssh_msg_send(ctxt->pam_csock,
 300                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 301                                 goto fail;
 302                         break;
 303                 case PAM_TEXT_INFO:
 304                         buffer_put_cstring(&buffer,
 305                             PAM_MSG_MEMBER(msg, i, msg));
 306                         if (ssh_msg_send(ctxt->pam_csock,
 307                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 308                                 goto fail;
 309                         break;
 310                 default:
 311                         goto fail;
 312                 }
 313                 buffer_clear(&buffer);
 314         }
 315         buffer_free(&buffer);
 316         *resp = reply;
 317         return (PAM_SUCCESS);
 318
 319  fail:
 320         for(i = 0; i < n; i++) {
 321                 if (reply[i].resp != NULL)
 322                         xfree(reply[i].resp);
 323         }
 324         xfree(reply);
 325         buffer_free(&buffer);
 326         return (PAM_CONV_ERR);
 327 }
 328
 329 /*
 330  * Authentication thread.
 331  */
 332 static void *
 333 sshpam_thread(void *ctxtp)
 334 {
 335         struct pam_ctxt *ctxt = ctxtp;
 336         Buffer buffer;
 337         struct pam_conv sshpam_conv;
 338 #ifndef USE_POSIX_THREADS
 339         extern char **environ;
 340         char **env_from_pam;
 341         u_int i;
 342         const char *pam_user;
 343
 344         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 345         setproctitle("%s [pam]", pam_user);
 346         environ[0] = NULL;
 347 #endif
 348
 349         sshpam_conv.conv = sshpam_thread_conv;
 350         sshpam_conv.appdata_ptr = ctxt;
 351
 352         if (sshpam_authctxt == NULL)
 353                 fatal("%s: PAM authctxt not initialized", __func__);
 354
 355         buffer_init(&buffer);
 356         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 357             (const void *)&sshpam_conv);
 358         if (sshpam_err != PAM_SUCCESS)
 359                 goto auth_fail;
 360         sshpam_err = pam_authenticate(sshpam_handle, 0);
 361         if (sshpam_err != PAM_SUCCESS)
 362                 goto auth_fail;
 363
 364         if (compat20) {
 365                 if (!do_pam_account())
 366                         goto auth_fail;
 367                 if (sshpam_authctxt->force_pwchange) {
 368                         sshpam_err = pam_chauthtok(sshpam_handle,
 369                             PAM_CHANGE_EXPIRED_AUTHTOK);
 370                         if (sshpam_err != PAM_SUCCESS)
 371                                 goto auth_fail;
 372                         pam_password_change_required(0);
 373                 }
 374         }
 375
 376         buffer_put_cstring(&buffer, "OK");
 377
 378 #ifndef USE_POSIX_THREADS
 379         /* Export variables set by do_pam_account */
 380         buffer_put_int(&buffer, sshpam_account_status);
 381         buffer_put_int(&buffer, sshpam_authctxt->force_pwchange);
 382
 383         /* Export any environment strings set in child */
 384         for(i = 0; environ[i] != NULL; i++)
 385                 ; /* Count */
 386         buffer_put_int(&buffer, i);
 387         for(i = 0; environ[i] != NULL; i++)
 388                 buffer_put_cstring(&buffer, environ[i]);
 389
 390         /* Export any environment strings set by PAM in child */
 391         env_from_pam = pam_getenvlist(sshpam_handle);
 392         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 393                 ; /* Count */
 394         buffer_put_int(&buffer, i);
 395         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 396                 buffer_put_cstring(&buffer, env_from_pam[i]);
 397 #endif /* USE_POSIX_THREADS */
 398
 399         /* XXX - can't do much about an error here */
 400         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 401         buffer_free(&buffer);
 402         pthread_exit(NULL);
 403
 404  auth_fail:
 405         buffer_put_cstring(&buffer,
 406             pam_strerror(sshpam_handle, sshpam_err));
 407         /* XXX - can't do much about an error here */
 408         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 409         buffer_free(&buffer);
 410         pthread_exit(NULL);
 411
 412         return (NULL); /* Avoid warning for non-pthread case */
 413 }
 414
 415 void
 416 sshpam_thread_cleanup(void)
 417 {
 418         struct pam_ctxt *ctxt = cleanup_ctxt;
 419
 420         debug3("PAM: %s entering", __func__);
 421         if (ctxt != NULL && ctxt->pam_thread != 0) {
 422                 pthread_cancel(ctxt->pam_thread);
 423                 pthread_join(ctxt->pam_thread, NULL);
 424                 close(ctxt->pam_psock);
 425                 close(ctxt->pam_csock);
 426                 memset(ctxt, 0, sizeof(*ctxt));
 427                 cleanup_ctxt = NULL;
 428         }
 429 }
 430
 431 static int
 432 sshpam_null_conv(int n, const struct pam_message **msg,
 433     struct pam_response **resp, void *data)
 434 {
 435         debug3("PAM: %s entering, %d messages", __func__, n);
 436         return (PAM_CONV_ERR);
 437 }
 438
 439 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 440
 441 void
 442 sshpam_cleanup(void)
 443 {
 444         debug("PAM: cleanup");
 445         if (sshpam_handle == NULL)
 446                 return;
 447         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 448         if (sshpam_cred_established) {
 449                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 450                 sshpam_cred_established = 0;
 451         }
 452         if (sshpam_session_open) {
 453                 pam_close_session(sshpam_handle, PAM_SILENT);
 454                 sshpam_session_open = 0;
 455         }
 456         sshpam_authenticated = 0;
 457         pam_end(sshpam_handle, sshpam_err);
 458         sshpam_handle = NULL;
 459 }
 460
 461 static int
 462 sshpam_init(Authctxt *authctxt)
 463 {
 464         extern char *__progname;
 465         const char *pam_rhost, *pam_user, *user = authctxt->user;
 466
 467         if (sshpam_handle != NULL) {
 468                 /* We already have a PAM context; check if the user matches */
 469                 sshpam_err = pam_get_item(sshpam_handle,
 470                     PAM_USER, (const void **)&pam_user);
 471                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 472                         return (0);
 473                 pam_end(sshpam_handle, sshpam_err);
 474                 sshpam_handle = NULL;
 475         }
 476         debug("PAM: initializing for \"%s\"", user);
 477         sshpam_err =
 478             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 479         sshpam_authctxt = authctxt;
 480
 481         if (sshpam_err != PAM_SUCCESS) {
 482                 pam_end(sshpam_handle, sshpam_err);
 483                 sshpam_handle = NULL;
 484                 return (-1);
 485         }
 486         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 487         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 488         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 489         if (sshpam_err != PAM_SUCCESS) {
 490                 pam_end(sshpam_handle, sshpam_err);
 491                 sshpam_handle = NULL;
 492                 return (-1);
 493         }
 494 #ifdef PAM_TTY_KLUDGE
 495         /*
 496          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 497          * sshd doesn't set the tty until too late in the auth process and
 498          * may not even set one (for tty-less connections)
 499          */
 500         debug("PAM: setting PAM_TTY to \"ssh\"");
 501         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 502         if (sshpam_err != PAM_SUCCESS) {
 503                 pam_end(sshpam_handle, sshpam_err);
 504                 sshpam_handle = NULL;
 505                 return (-1);
 506         }
 507 #endif
 508         return (0);
 509 }
 510
 511 static void *
 512 sshpam_init_ctx(Authctxt *authctxt)
 513 {
 514         struct pam_ctxt *ctxt;
 515         int socks[2];
 516
 517         debug3("PAM: %s entering", __func__);
 518         /* Refuse to start if we don't have PAM enabled */
 519         if (!options.use_pam)
 520                 return NULL;
 521
 522         /* Initialize PAM */
 523         if (sshpam_init(authctxt) == -1) {
 524                 error("PAM: initialization failed");
 525                 return (NULL);
 526         }
 527
 528         ctxt = xmalloc(sizeof *ctxt);
 529         memset(ctxt, 0, sizeof(*ctxt));
 530
 531         /* Start the authentication thread */
 532         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 533                 error("PAM: failed create sockets: %s", strerror(errno));
 534                 xfree(ctxt);
 535                 return (NULL);
 536         }
 537         ctxt->pam_psock = socks[0];
 538         ctxt->pam_csock = socks[1];
 539         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 540                 error("PAM: failed to start authentication thread: %s",
 541                     strerror(errno));
 542                 close(socks[0]);
 543                 close(socks[1]);
 544                 xfree(ctxt);
 545                 return (NULL);
 546         }
 547         cleanup_ctxt = ctxt;
 548         return (ctxt);
 549 }
 550
 551 static int
 552 sshpam_query(void *ctx, char **name, char **info,
 553     u_int *num, char ***prompts, u_int **echo_on)
 554 {
 555         Buffer buffer;
 556         struct pam_ctxt *ctxt = ctx;
 557         size_t plen;
 558         u_char type;
 559         char *msg;
 560         size_t len;
 561
 562         debug3("PAM: %s entering", __func__);
 563         buffer_init(&buffer);
 564         *name = xstrdup("");
 565         *info = xstrdup("");
 566         *prompts = xmalloc(sizeof(char *));
 567         **prompts = NULL;
 568         plen = 0;
 569         *echo_on = xmalloc(sizeof(u_int));
 570         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 571                 type = buffer_get_char(&buffer);
 572                 msg = buffer_get_string(&buffer, NULL);
 573                 switch (type) {
 574                 case PAM_PROMPT_ECHO_ON:
 575                 case PAM_PROMPT_ECHO_OFF:
 576                         *num = 1;
 577                         len = plen + strlen(msg) + 1;
 578                         **prompts = xrealloc(**prompts, len);
 579                         plen += snprintf(**prompts + plen, len, "%s", msg);
 580                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 581                         xfree(msg);
 582                         return (0);
 583                 case PAM_ERROR_MSG:
 584                 case PAM_TEXT_INFO:
 585                         /* accumulate messages */
 586                         len = plen + strlen(msg) + 2;
 587                         **prompts = xrealloc(**prompts, len);
 588                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 589                         xfree(msg);
 590                         break;
 591                 case PAM_SUCCESS:
 592                 case PAM_AUTH_ERR:
 593                         if (**prompts != NULL) {
 594                                 /* drain any accumulated messages */
 595                                 debug("PAM: %s", **prompts);
 596                                 buffer_append(&loginmsg, **prompts,
 597                                     strlen(**prompts));
 598                                 xfree(**prompts);
 599                                 **prompts = NULL;
 600                         }
 601                         if (type == PAM_SUCCESS) {
 602                                 import_environments(&buffer);
 603                                 *num = 0;
 604                                 **echo_on = 0;
 605                                 ctxt->pam_done = 1;
 606                                 xfree(msg);
 607                                 return (0);
 608                         }
 609                         error("PAM: %s for %s%.100s from %.100s", msg,
 610                             sshpam_authctxt->valid ? "" : "illegal user ",
 611                             sshpam_authctxt->user,
 612                             get_remote_name_or_ip(utmp_len, options.use_dns));
 613                         /* FALLTHROUGH */
 614                 default:
 615                         *num = 0;
 616                         **echo_on = 0;
 617                         xfree(msg);
 618                         ctxt->pam_done = -1;
 619                         return (-1);
 620                 }
 621         }
 622         return (-1);
 623 }
 624
 625 /* XXX - see also comment in auth-chall.c:verify_response */
 626 static int
 627 sshpam_respond(void *ctx, u_int num, char **resp)
 628 {
 629         Buffer buffer;
 630         struct pam_ctxt *ctxt = ctx;
 631
 632         debug2("PAM: %s entering, %d responses", __func__, num);
 633         switch (ctxt->pam_done) {
 634         case 1:
 635                 sshpam_authenticated = 1;
 636                 return (0);
 637         case 0:
 638                 break;
 639         default:
 640                 return (-1);
 641         }
 642         if (num != 1) {
 643                 error("PAM: expected one response, got %u", num);
 644                 return (-1);
 645         }
 646         buffer_init(&buffer);
 647         buffer_put_cstring(&buffer, *resp);
 648         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 649                 buffer_free(&buffer);
 650                 return (-1);
 651         }
 652         buffer_free(&buffer);
 653         return (1);
 654 }
 655
 656 static void
 657 sshpam_free_ctx(void *ctxtp)
 658 {
 659         struct pam_ctxt *ctxt = ctxtp;
 660
 661         debug3("PAM: %s entering", __func__);
 662         sshpam_thread_cleanup();
 663         xfree(ctxt);
 664         /*
 665          * We don't call sshpam_cleanup() here because we may need the PAM
 666          * handle at a later stage, e.g. when setting up a session.  It's
 667          * still on the cleanup list, so pam_end() *will* be called before
 668          * the server process terminates.
 669          */
 670 }
 671
 672 KbdintDevice sshpam_device = {
 673         "pam",
 674         sshpam_init_ctx,
 675         sshpam_query,
 676         sshpam_respond,
 677         sshpam_free_ctx
 678 };
 679
 680 KbdintDevice mm_sshpam_device = {
 681         "pam",
 682         mm_sshpam_init_ctx,
 683         mm_sshpam_query,
 684         mm_sshpam_respond,
 685         mm_sshpam_free_ctx
 686 };
 687
 688 /*
 689  * This replaces auth-pam.c
 690  */
 691 void
 692 start_pam(Authctxt *authctxt)
 693 {
 694         if (!options.use_pam)
 695                 fatal("PAM: initialisation requested when UsePAM=no");
 696
 697         if (sshpam_init(authctxt) == -1)
 698                 fatal("PAM: initialisation failed");
 699 }
 700
 701 void
 702 finish_pam(void)
 703 {
 704         sshpam_cleanup();
 705 }
 706
 707 u_int
 708 do_pam_account(void)
 709 {
 710         if (sshpam_account_status != -1)
 711                 return (sshpam_account_status);
 712
 713         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 714         debug3("PAM: %s pam_acct_mgmt = %d", __func__, sshpam_err);
 715
 716         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
 717                 sshpam_account_status = 0;
 718                 return (sshpam_account_status);
 719         }
 720
 721         if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
 722                 pam_password_change_required(1);
 723
 724         sshpam_account_status = 1;
 725         return (sshpam_account_status);
 726 }
 727
 728 void
 729 do_pam_set_tty(const char *tty)
 730 {
 731         if (tty != NULL) {
 732                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 733                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 734                 if (sshpam_err != PAM_SUCCESS)
 735                         fatal("PAM: failed to set PAM_TTY: %s",
 736                             pam_strerror(sshpam_handle, sshpam_err));
 737         }
 738 }
 739
 740 void
 741 do_pam_setcred(int init)
 742 {
 743         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 744             (const void *)&null_conv);
 745         if (sshpam_err != PAM_SUCCESS)
 746                 fatal("PAM: failed to set PAM_CONV: %s",
 747                     pam_strerror(sshpam_handle, sshpam_err));
 748         if (init) {
 749                 debug("PAM: establishing credentials");
 750                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 751         } else {
 752                 debug("PAM: reinitializing credentials");
 753                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 754         }
 755         if (sshpam_err == PAM_SUCCESS) {
 756                 sshpam_cred_established = 1;
 757                 return;
 758         }
 759         if (sshpam_authenticated)
 760                 fatal("PAM: pam_setcred(): %s",
 761                     pam_strerror(sshpam_handle, sshpam_err));
 762         else
 763                 debug("PAM: pam_setcred(): %s",
 764                     pam_strerror(sshpam_handle, sshpam_err));
 765 }
 766
 767 static int
 768 pam_tty_conv(int n, const struct pam_message **msg,
 769     struct pam_response **resp, void *data)
 770 {
 771         char input[PAM_MAX_MSG_SIZE];
 772         struct pam_response *reply;
 773         int i;
 774
 775         debug3("PAM: %s called with %d messages", __func__, n);
 776
 777         *resp = NULL;
 778
 779         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
 780                 return (PAM_CONV_ERR);
 781
 782         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 783                 return (PAM_CONV_ERR);
 784         memset(reply, 0, n * sizeof(*reply));
 785
 786         for (i = 0; i < n; ++i) {
 787                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 788                 case PAM_PROMPT_ECHO_OFF:
 789                         reply[i].resp =
 790                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 791                             RP_ALLOW_STDIN);
 792                         reply[i].resp_retcode = PAM_SUCCESS;
 793                         break;
 794                 case PAM_PROMPT_ECHO_ON:
 795                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 796                         fgets(input, sizeof input, stdin);
 797                         reply[i].resp = xstrdup(input);
 798                         reply[i].resp_retcode = PAM_SUCCESS;
 799                         break;
 800                 case PAM_ERROR_MSG:
 801                 case PAM_TEXT_INFO:
 802                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 803                         reply[i].resp_retcode = PAM_SUCCESS;
 804                         break;
 805                 default:
 806                         goto fail;
 807                 }
 808         }
 809         *resp = reply;
 810         return (PAM_SUCCESS);
 811
 812  fail:
 813         for(i = 0; i < n; i++) {
 814                 if (reply[i].resp != NULL)
 815                         xfree(reply[i].resp);
 816         }
 817         xfree(reply);
 818         return (PAM_CONV_ERR);
 819 }
 820
 821 static struct pam_conv tty_conv = { pam_tty_conv, NULL };
 822
 823 /*
 824  * XXX this should be done in the authentication phase, but ssh1 doesn't
 825  * support that
 826  */
 827 void
 828 do_pam_chauthtok(void)
 829 {
 830         if (use_privsep)
 831                 fatal("Password expired (unable to change with privsep)");
 832         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 833             (const void *)&tty_conv);
 834         if (sshpam_err != PAM_SUCCESS)
 835                 fatal("PAM: failed to set PAM_CONV: %s",
 836                     pam_strerror(sshpam_handle, sshpam_err));
 837         debug("PAM: changing password");
 838         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 839         if (sshpam_err != PAM_SUCCESS)
 840                 fatal("PAM: pam_chauthtok(): %s",
 841                     pam_strerror(sshpam_handle, sshpam_err));
 842 }
 843
 844 static int
 845 pam_store_conv(int n, const struct pam_message **msg,
 846     struct pam_response **resp, void *data)
 847 {
 848         struct pam_response *reply;
 849         int i;
 850         size_t len;
 851
 852         debug3("PAM: %s called with %d messages", __func__, n);
 853         *resp = NULL;
 854
 855         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 856                 return (PAM_CONV_ERR);
 857
 858         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 859                 return (PAM_CONV_ERR);
 860         memset(reply, 0, n * sizeof(*reply));
 861
 862         for (i = 0; i < n; ++i) {
 863                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 864                 case PAM_ERROR_MSG:
 865                 case PAM_TEXT_INFO:
 866                         len = strlen(PAM_MSG_MEMBER(msg, i, msg));
 867                         buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
 868                         buffer_append(&loginmsg, "\n", 1 );
 869                         reply[i].resp_retcode = PAM_SUCCESS;
 870                         break;
 871                 default:
 872                         goto fail;
 873                 }
 874         }
 875         *resp = reply;
 876         return (PAM_SUCCESS);
 877
 878  fail:
 879         for(i = 0; i < n; i++) {
 880                 if (reply[i].resp != NULL)
 881                         xfree(reply[i].resp);
 882         }
 883         xfree(reply);
 884         return (PAM_CONV_ERR);
 885 }
 886
 887 static struct pam_conv store_conv = { pam_store_conv, NULL };
 888
 889 void
 890 do_pam_session(void)
 891 {
 892         debug3("PAM: opening session");
 893         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 894             (const void *)&store_conv);
 895         if (sshpam_err != PAM_SUCCESS)
 896                 fatal("PAM: failed to set PAM_CONV: %s",
 897                     pam_strerror(sshpam_handle, sshpam_err));
 898         sshpam_err = pam_open_session(sshpam_handle, 0);
 899         if (sshpam_err != PAM_SUCCESS)
 900                 fatal("PAM: pam_open_session(): %s",
 901                     pam_strerror(sshpam_handle, sshpam_err));
 902         sshpam_session_open = 1;
 903 }
 904
 905 /*
 906  * Set a PAM environment string. We need to do this so that the session
 907  * modules can handle things like Kerberos/GSI credentials that appear
 908  * during the ssh authentication process.
 909  */
 910 int
 911 do_pam_putenv(char *name, char *value)
 912 {
 913         int ret = 1;
 914 #ifdef HAVE_PAM_PUTENV
 915         char *compound;
 916         size_t len;
 917
 918         len = strlen(name) + strlen(value) + 2;
 919         compound = xmalloc(len);
 920
 921         snprintf(compound, len, "%s=%s", name, value);
 922         ret = pam_putenv(sshpam_handle, compound);
 923         xfree(compound);
 924 #endif
 925
 926         return (ret);
 927 }
 928
 929 char **
 930 fetch_pam_child_environment(void)
 931 {
 932         return sshpam_env;
 933 }
 934
 935 char **
 936 fetch_pam_environment(void)
 937 {
 938         return (pam_getenvlist(sshpam_handle));
 939 }
 940
 941 void
 942 free_pam_environment(char **env)
 943 {
 944         char **envp;
 945
 946         if (env == NULL)
 947                 return;
 948
 949         for (envp = env; *envp; envp++)
 950                 xfree(*envp);
 951         xfree(env);
 952 }
 953
 954 #endif /* USE_PAM */