auth-pam.c

   1 /*-
   2  * Copyright (c) 2002 Networks Associates Technology, Inc.
   3  * All rights reserved.
   4  *
   5  * This software was developed for the FreeBSD Project by ThinkSec AS and
   6  * NAI Labs, the Security Research Division of Network Associates, Inc.
   7  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
   8  * DARPA CHATS research program.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 /* Based on $FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des Exp $ */
  33 #include "includes.h"
  34 RCSID("$Id$");
  35
  36 #ifdef USE_PAM
  37 #if defined(HAVE_SECURITY_PAM_APPL_H)
  38 #include <security/pam_appl.h>
  39 #elif defined (HAVE_PAM_PAM_APPL_H)
  40 #include <pam/pam_appl.h>
  41 #endif
  42
  43 #include "auth.h"
  44 #include "auth-pam.h"
  45 #include "buffer.h"
  46 #include "bufaux.h"
  47 #include "canohost.h"
  48 #include "log.h"
  49 #include "monitor_wrap.h"
  50 #include "msg.h"
  51 #include "packet.h"
  52 #include "readpass.h"
  53 #include "servconf.h"
  54 #include "ssh2.h"
  55 #include "xmalloc.h"
  56 #include "auth-options.h"
  57
  58 extern ServerOptions options;
  59 extern Buffer loginmsg;
  60 extern int compat20;
  61
  62 #ifdef USE_POSIX_THREADS
  63 #include <pthread.h>
  64 /*
  65  * Avoid namespace clash when *not* using pthreads for systems *with*
  66  * pthreads, which unconditionally define pthread_t via sys/types.h
  67  * (e.g. Linux)
  68  */
  69 typedef pthread_t sp_pthread_t;
  70 #else
  71 typedef pid_t sp_pthread_t;
  72 #endif
  73
  74 struct pam_ctxt {
  75         sp_pthread_t     pam_thread;
  76         int              pam_psock;
  77         int              pam_csock;
  78         int              pam_done;
  79 };
  80
  81 static void sshpam_free_ctx(void *);
  82 static struct pam_ctxt *cleanup_ctxt;
  83
  84 #ifndef USE_POSIX_THREADS
  85 /*
  86  * Simulate threads with processes.
  87  */
  88
  89 static int sshpam_thread_status = -1;
  90 static mysig_t sshpam_oldsig;
  91
  92 static void
  93 sshpam_sigchld_handler(int sig)
  94 {
  95         if (cleanup_ctxt == NULL)
  96                 return; /* handler called after PAM cleanup, shouldn't happen */
  97         if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0) == -1)
  98                 return; /* couldn't wait for process */
  99         if (WIFSIGNALED(sshpam_thread_status) &&
 100             WTERMSIG(sshpam_thread_status) == SIGTERM)
 101                 return; /* terminated by pthread_cancel */
 102         if (!WIFEXITED(sshpam_thread_status))
 103                 fatal("PAM: authentication thread exited unexpectedly");
 104         if (WEXITSTATUS(sshpam_thread_status) != 0)
 105                 fatal("PAM: authentication thread exited uncleanly");
 106 }
 107
 108 static void
 109 pthread_exit(void *value __unused)
 110 {
 111         _exit(0);
 112 }
 113
 114 static int
 115 pthread_create(sp_pthread_t *thread, const void *attr __unused,
 116     void *(*thread_start)(void *), void *arg)
 117 {
 118         pid_t pid;
 119
 120         sshpam_thread_status = -1;
 121         switch ((pid = fork())) {
 122         case -1:
 123                 error("fork(): %s", strerror(errno));
 124                 return (-1);
 125         case 0:
 126                 thread_start(arg);
 127                 _exit(1);
 128         default:
 129                 *thread = pid;
 130                 sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
 131                 return (0);
 132         }
 133 }
 134
 135 static int
 136 pthread_cancel(sp_pthread_t thread)
 137 {
 138         signal(SIGCHLD, sshpam_oldsig);
 139         return (kill(thread, SIGTERM));
 140 }
 141
 142 static int
 143 pthread_join(sp_pthread_t thread, void **value __unused)
 144 {
 145         int status;
 146
 147         if (sshpam_thread_status != -1)
 148                 return (sshpam_thread_status);
 149         signal(SIGCHLD, sshpam_oldsig);
 150         waitpid(thread, &status, 0);
 151         return (status);
 152 }
 153 #endif
 154
 155
 156 static pam_handle_t *sshpam_handle = NULL;
 157 static int sshpam_err = 0;
 158 static int sshpam_authenticated = 0;
 159 static int sshpam_session_open = 0;
 160 static int sshpam_cred_established = 0;
 161 static int sshpam_account_status = -1;
 162 static char **sshpam_env = NULL;
 163 static Authctxt *sshpam_authctxt = NULL;
 164
 165 /* Some PAM implementations don't implement this */
 166 #ifndef HAVE_PAM_GETENVLIST
 167 static char **
 168 pam_getenvlist(pam_handle_t *pamh)
 169 {
 170         /*
 171          * XXX - If necessary, we can still support envrionment passing
 172          * for platforms without pam_getenvlist by searching for known
 173          * env vars (e.g. KRB5CCNAME) from the PAM environment.
 174          */
 175          return NULL;
 176 }
 177 #endif
 178
 179 void
 180 pam_password_change_required(int reqd)
 181 {
 182         debug3("%s %d", __func__, reqd);
 183         if (sshpam_authctxt == NULL)
 184                 fatal("%s: PAM authctxt not initialized", __func__);
 185         sshpam_authctxt->force_pwchange = reqd;
 186         if (reqd) {
 187                 no_port_forwarding_flag |= 2;
 188                 no_agent_forwarding_flag |= 2;
 189                 no_x11_forwarding_flag |= 2;
 190         } else {
 191                 no_port_forwarding_flag &= ~2;
 192                 no_agent_forwarding_flag &= ~2;
 193                 no_x11_forwarding_flag &= ~2;
 194         }
 195 }
 196
 197 /* Import regular and PAM environment from subprocess */
 198 static void
 199 import_environments(Buffer *b)
 200 {
 201         char *env;
 202         u_int i, num_env;
 203         int err;
 204
 205         debug3("PAM: %s entering", __func__);
 206
 207 #ifndef USE_POSIX_THREADS
 208         /* Import variables set by do_pam_account */
 209         sshpam_account_status = buffer_get_int(b);
 210         pam_password_change_required(buffer_get_int(b));
 211
 212         /* Import environment from subprocess */
 213         num_env = buffer_get_int(b);
 214         sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
 215         debug3("PAM: num env strings %d", num_env);
 216         for(i = 0; i < num_env; i++)
 217                 sshpam_env[i] = buffer_get_string(b, NULL);
 218
 219         sshpam_env[num_env] = NULL;
 220
 221         /* Import PAM environment from subprocess */
 222         num_env = buffer_get_int(b);
 223         debug("PAM: num PAM env strings %d", num_env);
 224         for(i = 0; i < num_env; i++) {
 225                 env = buffer_get_string(b, NULL);
 226
 227 #ifdef HAVE_PAM_PUTENV
 228                 /* Errors are not fatal here */
 229                 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
 230                         error("PAM: pam_putenv: %s",
 231                             pam_strerror(sshpam_handle, sshpam_err));
 232                 }
 233 #endif
 234         }
 235 #endif
 236 }
 237
 238 /*
 239  * Conversation function for authentication thread.
 240  */
 241 static int
 242 sshpam_thread_conv(int n, const struct pam_message **msg,
 243     struct pam_response **resp, void *data)
 244 {
 245         Buffer buffer;
 246         struct pam_ctxt *ctxt;
 247         struct pam_response *reply;
 248         int i;
 249
 250         debug3("PAM: %s entering, %d messages", __func__, n);
 251         *resp = NULL;
 252
 253         ctxt = data;
 254         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 255                 return (PAM_CONV_ERR);
 256
 257         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 258                 return (PAM_CONV_ERR);
 259         memset(reply, 0, n * sizeof(*reply));
 260
 261         buffer_init(&buffer);
 262         for (i = 0; i < n; ++i) {
 263                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 264                 case PAM_PROMPT_ECHO_OFF:
 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_PROMPT_ECHO_ON:
 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                         if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
 283                                 goto fail;
 284                         if (buffer_get_char(&buffer) != PAM_AUTHTOK)
 285                                 goto fail;
 286                         reply[i].resp = buffer_get_string(&buffer, NULL);
 287                         break;
 288                 case PAM_ERROR_MSG:
 289                         buffer_put_cstring(&buffer,
 290                             PAM_MSG_MEMBER(msg, i, msg));
 291                         if (ssh_msg_send(ctxt->pam_csock,
 292                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 293                                 goto fail;
 294                         break;
 295                 case PAM_TEXT_INFO:
 296                         buffer_put_cstring(&buffer,
 297                             PAM_MSG_MEMBER(msg, i, msg));
 298                         if (ssh_msg_send(ctxt->pam_csock,
 299                             PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
 300                                 goto fail;
 301                         break;
 302                 default:
 303                         goto fail;
 304                 }
 305                 buffer_clear(&buffer);
 306         }
 307         buffer_free(&buffer);
 308         *resp = reply;
 309         return (PAM_SUCCESS);
 310
 311  fail:
 312         for(i = 0; i < n; i++) {
 313                 if (reply[i].resp != NULL)
 314                         xfree(reply[i].resp);
 315         }
 316         xfree(reply);
 317         buffer_free(&buffer);
 318         return (PAM_CONV_ERR);
 319 }
 320
 321 /*
 322  * Authentication thread.
 323  */
 324 static void *
 325 sshpam_thread(void *ctxtp)
 326 {
 327         struct pam_ctxt *ctxt = ctxtp;
 328         Buffer buffer;
 329         struct pam_conv sshpam_conv;
 330 #ifndef USE_POSIX_THREADS
 331         extern char **environ;
 332         char **env_from_pam;
 333         u_int i;
 334         const char *pam_user;
 335
 336         pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
 337         setproctitle("%s [pam]", pam_user);
 338         environ[0] = NULL;
 339 #endif
 340
 341         sshpam_conv.conv = sshpam_thread_conv;
 342         sshpam_conv.appdata_ptr = ctxt;
 343
 344         if (sshpam_authctxt == NULL)
 345                 fatal("%s: PAM authctxt not initialized", __func__);
 346
 347         buffer_init(&buffer);
 348         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 349             (const void *)&sshpam_conv);
 350         if (sshpam_err != PAM_SUCCESS)
 351                 goto auth_fail;
 352         sshpam_err = pam_authenticate(sshpam_handle, 0);
 353         if (sshpam_err != PAM_SUCCESS)
 354                 goto auth_fail;
 355
 356         if (compat20) {
 357                 if (!do_pam_account())
 358                         goto auth_fail;
 359                 if (sshpam_authctxt->force_pwchange) {
 360                         sshpam_err = pam_chauthtok(sshpam_handle,
 361                             PAM_CHANGE_EXPIRED_AUTHTOK);
 362                         if (sshpam_err != PAM_SUCCESS)
 363                                 goto auth_fail;
 364                         pam_password_change_required(0);
 365                 }
 366         }
 367
 368         buffer_put_cstring(&buffer, "OK");
 369
 370 #ifndef USE_POSIX_THREADS
 371         /* Export variables set by do_pam_account */
 372         buffer_put_int(&buffer, sshpam_account_status);
 373         buffer_put_int(&buffer, sshpam_authctxt->force_pwchange);
 374
 375         /* Export any environment strings set in child */
 376         for(i = 0; environ[i] != NULL; i++)
 377                 ; /* Count */
 378         buffer_put_int(&buffer, i);
 379         for(i = 0; environ[i] != NULL; i++)
 380                 buffer_put_cstring(&buffer, environ[i]);
 381
 382         /* Export any environment strings set by PAM in child */
 383         env_from_pam = pam_getenvlist(sshpam_handle);
 384         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 385                 ; /* Count */
 386         buffer_put_int(&buffer, i);
 387         for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
 388                 buffer_put_cstring(&buffer, env_from_pam[i]);
 389 #endif /* USE_POSIX_THREADS */
 390
 391         /* XXX - can't do much about an error here */
 392         ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
 393         buffer_free(&buffer);
 394         pthread_exit(NULL);
 395
 396  auth_fail:
 397         buffer_put_cstring(&buffer,
 398             pam_strerror(sshpam_handle, sshpam_err));
 399         /* XXX - can't do much about an error here */
 400         ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
 401         buffer_free(&buffer);
 402         pthread_exit(NULL);
 403
 404         return (NULL); /* Avoid warning for non-pthread case */
 405 }
 406
 407 void
 408 sshpam_thread_cleanup(void)
 409 {
 410         struct pam_ctxt *ctxt = cleanup_ctxt;
 411
 412         debug3("PAM: %s entering", __func__);
 413         if (ctxt != NULL && ctxt->pam_thread != 0) {
 414                 pthread_cancel(ctxt->pam_thread);
 415                 pthread_join(ctxt->pam_thread, NULL);
 416                 close(ctxt->pam_psock);
 417                 close(ctxt->pam_csock);
 418                 memset(ctxt, 0, sizeof(*ctxt));
 419                 cleanup_ctxt = NULL;
 420         }
 421 }
 422
 423 static int
 424 sshpam_null_conv(int n, const struct pam_message **msg,
 425     struct pam_response **resp, void *data)
 426 {
 427         debug3("PAM: %s entering, %d messages", __func__, n);
 428         return (PAM_CONV_ERR);
 429 }
 430
 431 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 432
 433 void
 434 sshpam_cleanup(void)
 435 {
 436         debug("PAM: cleanup");
 437         if (sshpam_handle == NULL)
 438                 return;
 439         pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
 440         if (sshpam_cred_established) {
 441                 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
 442                 sshpam_cred_established = 0;
 443         }
 444         if (sshpam_session_open) {
 445                 pam_close_session(sshpam_handle, PAM_SILENT);
 446                 sshpam_session_open = 0;
 447         }
 448         sshpam_authenticated = 0;
 449         pam_end(sshpam_handle, sshpam_err);
 450         sshpam_handle = NULL;
 451 }
 452
 453 static int
 454 sshpam_init(Authctxt *authctxt)
 455 {
 456         extern u_int utmp_len;
 457         extern char *__progname;
 458         const char *pam_rhost, *pam_user, *user = authctxt->user;
 459
 460         if (sshpam_handle != NULL) {
 461                 /* We already have a PAM context; check if the user matches */
 462                 sshpam_err = pam_get_item(sshpam_handle,
 463                     PAM_USER, (const void **)&pam_user);
 464                 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 465                         return (0);
 466                 pam_end(sshpam_handle, sshpam_err);
 467                 sshpam_handle = NULL;
 468         }
 469         debug("PAM: initializing for \"%s\"", user);
 470         sshpam_err =
 471             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
 472         sshpam_authctxt = authctxt;
 473
 474         if (sshpam_err != PAM_SUCCESS) {
 475                 pam_end(sshpam_handle, sshpam_err);
 476                 sshpam_handle = NULL;
 477                 return (-1);
 478         }
 479         pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
 480         debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
 481         sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
 482         if (sshpam_err != PAM_SUCCESS) {
 483                 pam_end(sshpam_handle, sshpam_err);
 484                 sshpam_handle = NULL;
 485                 return (-1);
 486         }
 487 #ifdef PAM_TTY_KLUDGE
 488         /*
 489          * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
 490          * sshd doesn't set the tty until too late in the auth process and
 491          * may not even set one (for tty-less connections)
 492          */
 493         debug("PAM: setting PAM_TTY to \"ssh\"");
 494         sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
 495         if (sshpam_err != PAM_SUCCESS) {
 496                 pam_end(sshpam_handle, sshpam_err);
 497                 sshpam_handle = NULL;
 498                 return (-1);
 499         }
 500 #endif
 501         return (0);
 502 }
 503
 504 static void *
 505 sshpam_init_ctx(Authctxt *authctxt)
 506 {
 507         struct pam_ctxt *ctxt;
 508         int socks[2];
 509
 510         debug3("PAM: %s entering", __func__);
 511         /* Refuse to start if we don't have PAM enabled */
 512         if (!options.use_pam)
 513                 return NULL;
 514
 515         /* Initialize PAM */
 516         if (sshpam_init(authctxt) == -1) {
 517                 error("PAM: initialization failed");
 518                 return (NULL);
 519         }
 520
 521         ctxt = xmalloc(sizeof *ctxt);
 522         memset(ctxt, 0, sizeof(*ctxt));
 523
 524         /* Start the authentication thread */
 525         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
 526                 error("PAM: failed create sockets: %s", strerror(errno));
 527                 xfree(ctxt);
 528                 return (NULL);
 529         }
 530         ctxt->pam_psock = socks[0];
 531         ctxt->pam_csock = socks[1];
 532         if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
 533                 error("PAM: failed to start authentication thread: %s",
 534                     strerror(errno));
 535                 close(socks[0]);
 536                 close(socks[1]);
 537                 xfree(ctxt);
 538                 return (NULL);
 539         }
 540         cleanup_ctxt = ctxt;
 541         return (ctxt);
 542 }
 543
 544 static int
 545 sshpam_query(void *ctx, char **name, char **info,
 546     u_int *num, char ***prompts, u_int **echo_on)
 547 {
 548         Buffer buffer;
 549         struct pam_ctxt *ctxt = ctx;
 550         size_t plen;
 551         u_char type;
 552         char *msg;
 553         size_t len;
 554
 555         debug3("PAM: %s entering", __func__);
 556         buffer_init(&buffer);
 557         *name = xstrdup("");
 558         *info = xstrdup("");
 559         *prompts = xmalloc(sizeof(char *));
 560         **prompts = NULL;
 561         plen = 0;
 562         *echo_on = xmalloc(sizeof(u_int));
 563         while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
 564                 type = buffer_get_char(&buffer);
 565                 msg = buffer_get_string(&buffer, NULL);
 566                 switch (type) {
 567                 case PAM_PROMPT_ECHO_ON:
 568                 case PAM_PROMPT_ECHO_OFF:
 569                         *num = 1;
 570                         len = plen + strlen(msg) + 1;
 571                         **prompts = xrealloc(**prompts, len);
 572                         plen += snprintf(**prompts + plen, len, "%s", msg);
 573                         **echo_on = (type == PAM_PROMPT_ECHO_ON);
 574                         xfree(msg);
 575                         return (0);
 576                 case PAM_ERROR_MSG:
 577                 case PAM_TEXT_INFO:
 578                         /* accumulate messages */
 579                         len = plen + strlen(msg) + 2;
 580                         **prompts = xrealloc(**prompts, len);
 581                         plen += snprintf(**prompts + plen, len, "%s\n", msg);
 582                         xfree(msg);
 583                         break;
 584                 case PAM_SUCCESS:
 585                 case PAM_AUTH_ERR:
 586                         if (**prompts != NULL) {
 587                                 /* drain any accumulated messages */
 588                                 debug("PAM: %s", **prompts);
 589                                 buffer_append(&loginmsg, **prompts,
 590                                     strlen(**prompts));
 591                                 xfree(**prompts);
 592                                 **prompts = NULL;
 593                         }
 594                         if (type == PAM_SUCCESS) {
 595                                 import_environments(&buffer);
 596                                 *num = 0;
 597                                 **echo_on = 0;
 598                                 ctxt->pam_done = 1;
 599                                 xfree(msg);
 600                                 return (0);
 601                         }
 602                         error("PAM: %s", msg);
 603                         /* FALLTHROUGH */
 604                 default:
 605                         *num = 0;
 606                         **echo_on = 0;
 607                         xfree(msg);
 608                         ctxt->pam_done = -1;
 609                         return (-1);
 610                 }
 611         }
 612         return (-1);
 613 }
 614
 615 /* XXX - see also comment in auth-chall.c:verify_response */
 616 static int
 617 sshpam_respond(void *ctx, u_int num, char **resp)
 618 {
 619         Buffer buffer;
 620         struct pam_ctxt *ctxt = ctx;
 621
 622         debug2("PAM: %s entering, %d responses", __func__, num);
 623         switch (ctxt->pam_done) {
 624         case 1:
 625                 sshpam_authenticated = 1;
 626                 return (0);
 627         case 0:
 628                 break;
 629         default:
 630                 return (-1);
 631         }
 632         if (num != 1) {
 633                 error("PAM: expected one response, got %u", num);
 634                 return (-1);
 635         }
 636         buffer_init(&buffer);
 637         buffer_put_cstring(&buffer, *resp);
 638         if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
 639                 buffer_free(&buffer);
 640                 return (-1);
 641         }
 642         buffer_free(&buffer);
 643         return (1);
 644 }
 645
 646 static void
 647 sshpam_free_ctx(void *ctxtp)
 648 {
 649         struct pam_ctxt *ctxt = ctxtp;
 650
 651         debug3("PAM: %s entering", __func__);
 652         sshpam_thread_cleanup();
 653         xfree(ctxt);
 654         /*
 655          * We don't call sshpam_cleanup() here because we may need the PAM
 656          * handle at a later stage, e.g. when setting up a session.  It's
 657          * still on the cleanup list, so pam_end() *will* be called before
 658          * the server process terminates.
 659          */
 660 }
 661
 662 KbdintDevice sshpam_device = {
 663         "pam",
 664         sshpam_init_ctx,
 665         sshpam_query,
 666         sshpam_respond,
 667         sshpam_free_ctx
 668 };
 669
 670 KbdintDevice mm_sshpam_device = {
 671         "pam",
 672         mm_sshpam_init_ctx,
 673         mm_sshpam_query,
 674         mm_sshpam_respond,
 675         mm_sshpam_free_ctx
 676 };
 677
 678 /*
 679  * This replaces auth-pam.c
 680  */
 681 void
 682 start_pam(Authctxt *authctxt)
 683 {
 684         if (!options.use_pam)
 685                 fatal("PAM: initialisation requested when UsePAM=no");
 686
 687         if (sshpam_init(authctxt) == -1)
 688                 fatal("PAM: initialisation failed");
 689 }
 690
 691 void
 692 finish_pam(void)
 693 {
 694         sshpam_cleanup();
 695 }
 696
 697 u_int
 698 do_pam_account(void)
 699 {
 700         if (sshpam_account_status != -1)
 701                 return (sshpam_account_status);
 702
 703         sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
 704         debug3("PAM: %s pam_acct_mgmt = %d", __func__, sshpam_err);
 705
 706         if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
 707                 sshpam_account_status = 0;
 708                 return (sshpam_account_status);
 709         }
 710
 711         if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
 712                 pam_password_change_required(1);
 713
 714         sshpam_account_status = 1;
 715         return (sshpam_account_status);
 716 }
 717
 718 void
 719 do_pam_set_tty(const char *tty)
 720 {
 721         if (tty != NULL) {
 722                 debug("PAM: setting PAM_TTY to \"%s\"", tty);
 723                 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
 724                 if (sshpam_err != PAM_SUCCESS)
 725                         fatal("PAM: failed to set PAM_TTY: %s",
 726                             pam_strerror(sshpam_handle, sshpam_err));
 727         }
 728 }
 729
 730 void
 731 do_pam_setcred(int init)
 732 {
 733         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 734             (const void *)&null_conv);
 735         if (sshpam_err != PAM_SUCCESS)
 736                 fatal("PAM: failed to set PAM_CONV: %s",
 737                     pam_strerror(sshpam_handle, sshpam_err));
 738         if (init) {
 739                 debug("PAM: establishing credentials");
 740                 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
 741         } else {
 742                 debug("PAM: reinitializing credentials");
 743                 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
 744         }
 745         if (sshpam_err == PAM_SUCCESS) {
 746                 sshpam_cred_established = 1;
 747                 return;
 748         }
 749         if (sshpam_authenticated)
 750                 fatal("PAM: pam_setcred(): %s",
 751                     pam_strerror(sshpam_handle, sshpam_err));
 752         else
 753                 debug("PAM: pam_setcred(): %s",
 754                     pam_strerror(sshpam_handle, sshpam_err));
 755 }
 756
 757 static int
 758 pam_tty_conv(int n, const struct pam_message **msg,
 759     struct pam_response **resp, void *data)
 760 {
 761         char input[PAM_MAX_MSG_SIZE];
 762         struct pam_response *reply;
 763         int i;
 764
 765         debug3("PAM: %s called with %d messages", __func__, n);
 766
 767         *resp = NULL;
 768
 769         if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
 770                 return (PAM_CONV_ERR);
 771
 772         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 773                 return (PAM_CONV_ERR);
 774         memset(reply, 0, n * sizeof(*reply));
 775
 776         for (i = 0; i < n; ++i) {
 777                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 778                 case PAM_PROMPT_ECHO_OFF:
 779                         reply[i].resp =
 780                             read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
 781                             RP_ALLOW_STDIN);
 782                         reply[i].resp_retcode = PAM_SUCCESS;
 783                         break;
 784                 case PAM_PROMPT_ECHO_ON:
 785                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 786                         fgets(input, sizeof input, stdin);
 787                         reply[i].resp = xstrdup(input);
 788                         reply[i].resp_retcode = PAM_SUCCESS;
 789                         break;
 790                 case PAM_ERROR_MSG:
 791                 case PAM_TEXT_INFO:
 792                         fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
 793                         reply[i].resp_retcode = PAM_SUCCESS;
 794                         break;
 795                 default:
 796                         goto fail;
 797                 }
 798         }
 799         *resp = reply;
 800         return (PAM_SUCCESS);
 801
 802  fail:
 803         for(i = 0; i < n; i++) {
 804                 if (reply[i].resp != NULL)
 805                         xfree(reply[i].resp);
 806         }
 807         xfree(reply);
 808         return (PAM_CONV_ERR);
 809 }
 810
 811 static struct pam_conv tty_conv = { pam_tty_conv, NULL };
 812
 813 /*
 814  * XXX this should be done in the authentication phase, but ssh1 doesn't
 815  * support that
 816  */
 817 void
 818 do_pam_chauthtok(void)
 819 {
 820         if (use_privsep)
 821                 fatal("Password expired (unable to change with privsep)");
 822         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 823             (const void *)&tty_conv);
 824         if (sshpam_err != PAM_SUCCESS)
 825                 fatal("PAM: failed to set PAM_CONV: %s",
 826                     pam_strerror(sshpam_handle, sshpam_err));
 827         debug("PAM: changing password");
 828         sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
 829         if (sshpam_err != PAM_SUCCESS)
 830                 fatal("PAM: pam_chauthtok(): %s",
 831                     pam_strerror(sshpam_handle, sshpam_err));
 832 }
 833
 834 static int
 835 pam_store_conv(int n, const struct pam_message **msg,
 836     struct pam_response **resp, void *data)
 837 {
 838         struct pam_response *reply;
 839         int i;
 840         size_t len;
 841
 842         debug3("PAM: %s called with %d messages", __func__, n);
 843         *resp = NULL;
 844
 845         if (n <= 0 || n > PAM_MAX_NUM_MSG)
 846                 return (PAM_CONV_ERR);
 847
 848         if ((reply = malloc(n * sizeof(*reply))) == NULL)
 849                 return (PAM_CONV_ERR);
 850         memset(reply, 0, n * sizeof(*reply));
 851
 852         for (i = 0; i < n; ++i) {
 853                 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
 854                 case PAM_ERROR_MSG:
 855                 case PAM_TEXT_INFO:
 856                         len = strlen(PAM_MSG_MEMBER(msg, i, msg));
 857                         buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
 858                         buffer_append(&loginmsg, "\n", 1 );
 859                         reply[i].resp_retcode = PAM_SUCCESS;
 860                         break;
 861                 default:
 862                         goto fail;
 863                 }
 864         }
 865         *resp = reply;
 866         return (PAM_SUCCESS);
 867
 868  fail:
 869         for(i = 0; i < n; i++) {
 870                 if (reply[i].resp != NULL)
 871                         xfree(reply[i].resp);
 872         }
 873         xfree(reply);
 874         return (PAM_CONV_ERR);
 875 }
 876
 877 static struct pam_conv store_conv = { pam_store_conv, NULL };
 878
 879 void
 880 do_pam_session(void)
 881 {
 882         debug3("PAM: opening session");
 883         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
 884             (const void *)&store_conv);
 885         if (sshpam_err != PAM_SUCCESS)
 886                 fatal("PAM: failed to set PAM_CONV: %s",
 887                     pam_strerror(sshpam_handle, sshpam_err));
 888         sshpam_err = pam_open_session(sshpam_handle, 0);
 889         if (sshpam_err != PAM_SUCCESS)
 890                 fatal("PAM: pam_open_session(): %s",
 891                     pam_strerror(sshpam_handle, sshpam_err));
 892         sshpam_session_open = 1;
 893 }
 894
 895 /*
 896  * Set a PAM environment string. We need to do this so that the session
 897  * modules can handle things like Kerberos/GSI credentials that appear
 898  * during the ssh authentication process.
 899  */
 900 int
 901 do_pam_putenv(char *name, char *value)
 902 {
 903         int ret = 1;
 904 #ifdef HAVE_PAM_PUTENV
 905         char *compound;
 906         size_t len;
 907
 908         len = strlen(name) + strlen(value) + 2;
 909         compound = xmalloc(len);
 910
 911         snprintf(compound, len, "%s=%s", name, value);
 912         ret = pam_putenv(sshpam_handle, compound);
 913         xfree(compound);
 914 #endif
 915
 916         return (ret);
 917 }
 918
 919 char **
 920 fetch_pam_child_environment(void)
 921 {
 922         return sshpam_env;
 923 }
 924
 925 char **
 926 fetch_pam_environment(void)
 927 {
 928         return (pam_getenvlist(sshpam_handle));
 929 }
 930
 931 void
 932 free_pam_environment(char **env)
 933 {
 934         char **envp;
 935
 936         if (env == NULL)
 937                 return;
 938
 939         for (envp = env; *envp; envp++)
 940                 xfree(*envp);
 941         xfree(env);
 942 }
 943
 944 #endif /* USE_PAM */