crypto/openssh/monitor.c

   1 /* $OpenBSD: monitor.c,v 1.161 2016/07/22 03:39:13 djm Exp $ */
   2 /*
   3  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
   4  * Copyright 2002 Markus Friedl <markus@openbsd.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "includes.h"
  29
  30 #include <sys/types.h>
  31 #include <sys/socket.h>
  32 #include "openbsd-compat/sys-tree.h"
  33 #include <sys/wait.h>
  34
  35 #include <errno.h>
  36 #include <fcntl.h>
  37 #include <limits.h>
  38 #ifdef HAVE_PATHS_H
  39 #include <paths.h>
  40 #endif
  41 #include <pwd.h>
  42 #include <signal.h>
  43 #ifdef HAVE_STDINT_H
  44 #include <stdint.h>
  45 #endif
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include <stdarg.h>
  49 #include <stdio.h>
  50 #include <unistd.h>
  51 #ifdef HAVE_POLL_H
  52 #include <poll.h>
  53 #else
  54 # ifdef HAVE_SYS_POLL_H
  55 #  include <sys/poll.h>
  56 # endif
  57 #endif
  58
  59 #ifdef SKEY
  60 #include <skey.h>
  61 #endif
  62
  63 #ifdef WITH_OPENSSL
  64 #include <openssl/dh.h>
  65 #endif
  66
  67 #include "openbsd-compat/sys-queue.h"
  68 #include "atomicio.h"
  69 #include "xmalloc.h"
  70 #include "ssh.h"
  71 #include "key.h"
  72 #include "buffer.h"
  73 #include "hostfile.h"
  74 #include "auth.h"
  75 #include "cipher.h"
  76 #include "kex.h"
  77 #include "dh.h"
  78 #include "auth-pam.h"
  79 #ifdef TARGET_OS_MAC    /* XXX Broken krb5 headers on Mac */
  80 #undef TARGET_OS_MAC
  81 #include "zlib.h"
  82 #define TARGET_OS_MAC 1
  83 #else
  84 #include "zlib.h"
  85 #endif
  86 #include "packet.h"
  87 #include "auth-options.h"
  88 #include "sshpty.h"
  89 #include "channels.h"
  90 #include "session.h"
  91 #include "sshlogin.h"
  92 #include "canohost.h"
  93 #include "log.h"
  94 #include "misc.h"
  95 #include "servconf.h"
  96 #include "monitor.h"
  97 #include "monitor_mm.h"
  98 #ifdef GSSAPI
  99 #include "ssh-gss.h"
 100 #endif
 101 #include "monitor_wrap.h"
 102 #include "monitor_fdpass.h"
 103 #include "compat.h"
 104 #include "ssh2.h"
 105 #include "authfd.h"
 106 #include "match.h"
 107 #include "ssherr.h"
 108
 109 #ifdef GSSAPI
 110 static Gssctxt *gsscontext = NULL;
 111 #endif
 112
 113 /* Imports */
 114 extern ServerOptions options;
 115 extern u_int utmp_len;
 116 extern u_char session_id[];
 117 extern Buffer auth_debug;
 118 extern int auth_debug_init;
 119 extern Buffer loginmsg;
 120
 121 /* State exported from the child */
 122 static struct sshbuf *child_state;
 123
 124 /* Functions on the monitor that answer unprivileged requests */
 125
 126 int mm_answer_moduli(int, Buffer *);
 127 int mm_answer_sign(int, Buffer *);
 128 int mm_answer_pwnamallow(int, Buffer *);
 129 int mm_answer_auth2_read_banner(int, Buffer *);
 130 int mm_answer_authserv(int, Buffer *);
 131 int mm_answer_authpassword(int, Buffer *);
 132 int mm_answer_bsdauthquery(int, Buffer *);
 133 int mm_answer_bsdauthrespond(int, Buffer *);
 134 int mm_answer_skeyquery(int, Buffer *);
 135 int mm_answer_skeyrespond(int, Buffer *);
 136 int mm_answer_keyallowed(int, Buffer *);
 137 int mm_answer_keyverify(int, Buffer *);
 138 int mm_answer_pty(int, Buffer *);
 139 int mm_answer_pty_cleanup(int, Buffer *);
 140 int mm_answer_term(int, Buffer *);
 141 int mm_answer_rsa_keyallowed(int, Buffer *);
 142 int mm_answer_rsa_challenge(int, Buffer *);
 143 int mm_answer_rsa_response(int, Buffer *);
 144 int mm_answer_sesskey(int, Buffer *);
 145 int mm_answer_sessid(int, Buffer *);
 146
 147 #ifdef USE_PAM
 148 int mm_answer_pam_start(int, Buffer *);
 149 int mm_answer_pam_account(int, Buffer *);
 150 int mm_answer_pam_init_ctx(int, Buffer *);
 151 int mm_answer_pam_query(int, Buffer *);
 152 int mm_answer_pam_respond(int, Buffer *);
 153 int mm_answer_pam_free_ctx(int, Buffer *);
 154 #endif
 155
 156 #ifdef GSSAPI
 157 int mm_answer_gss_setup_ctx(int, Buffer *);
 158 int mm_answer_gss_accept_ctx(int, Buffer *);
 159 int mm_answer_gss_userok(int, Buffer *);
 160 int mm_answer_gss_checkmic(int, Buffer *);
 161 #endif
 162
 163 #ifdef SSH_AUDIT_EVENTS
 164 int mm_answer_audit_event(int, Buffer *);
 165 int mm_answer_audit_command(int, Buffer *);
 166 #endif
 167
 168 static int monitor_read_log(struct monitor *);
 169
 170 static Authctxt *authctxt;
 171
 172 #ifdef WITH_SSH1
 173 static BIGNUM *ssh1_challenge = NULL;   /* used for ssh1 rsa auth */
 174 #endif
 175
 176 /* local state for key verify */
 177 static u_char *key_blob = NULL;
 178 static u_int key_bloblen = 0;
 179 static int key_blobtype = MM_NOKEY;
 180 static char *hostbased_cuser = NULL;
 181 static char *hostbased_chost = NULL;
 182 static char *auth_method = "unknown";
 183 static char *auth_submethod = NULL;
 184 static u_int session_id2_len = 0;
 185 static u_char *session_id2 = NULL;
 186 static pid_t monitor_child_pid;
 187
 188 struct mon_table {
 189         enum monitor_reqtype type;
 190         int flags;
 191         int (*f)(int, Buffer *);
 192 };
 193
 194 #define MON_ISAUTH      0x0004  /* Required for Authentication */
 195 #define MON_AUTHDECIDE  0x0008  /* Decides Authentication */
 196 #define MON_ONCE        0x0010  /* Disable after calling */
 197 #define MON_ALOG        0x0020  /* Log auth attempt without authenticating */
 198
 199 #define MON_AUTH        (MON_ISAUTH|MON_AUTHDECIDE)
 200
 201 #define MON_PERMIT      0x1000  /* Request is permitted */
 202
 203 struct mon_table mon_dispatch_proto20[] = {
 204 #ifdef WITH_OPENSSL
 205     {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli},
 206 #endif
 207     {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
 208     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
 209     {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
 210     {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
 211     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 212 #ifdef USE_PAM
 213     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
 214     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
 215     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
 216     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
 217     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
 218     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 219 #endif
 220 #ifdef SSH_AUDIT_EVENTS
 221     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 222 #endif
 223 #ifdef BSD_AUTH
 224     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
 225     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
 226 #endif
 227 #ifdef SKEY
 228     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
 229     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
 230 #endif
 231     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
 232     {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
 233 #ifdef GSSAPI
 234     {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx},
 235     {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx},
 236     {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok},
 237     {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic},
 238 #endif
 239     {0, 0, NULL}
 240 };
 241
 242 struct mon_table mon_dispatch_postauth20[] = {
 243 #ifdef WITH_OPENSSL
 244     {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
 245 #endif
 246     {MONITOR_REQ_SIGN, 0, mm_answer_sign},
 247     {MONITOR_REQ_PTY, 0, mm_answer_pty},
 248     {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
 249     {MONITOR_REQ_TERM, 0, mm_answer_term},
 250 #ifdef SSH_AUDIT_EVENTS
 251     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 252     {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
 253 #endif
 254     {0, 0, NULL}
 255 };
 256
 257 struct mon_table mon_dispatch_proto15[] = {
 258 #ifdef WITH_SSH1
 259     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
 260     {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey},
 261     {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid},
 262     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 263     {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_rsa_keyallowed},
 264     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_keyallowed},
 265     {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge},
 266     {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response},
 267 #ifdef BSD_AUTH
 268     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
 269     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
 270 #endif
 271 #ifdef SKEY
 272     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
 273     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
 274 #endif
 275 #ifdef USE_PAM
 276     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
 277     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
 278     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
 279     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
 280     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
 281     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 282 #endif
 283 #ifdef SSH_AUDIT_EVENTS
 284     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 285 #endif
 286 #endif /* WITH_SSH1 */
 287     {0, 0, NULL}
 288 };
 289
 290 struct mon_table mon_dispatch_postauth15[] = {
 291 #ifdef WITH_SSH1
 292     {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty},
 293     {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup},
 294     {MONITOR_REQ_TERM, 0, mm_answer_term},
 295 #ifdef SSH_AUDIT_EVENTS
 296     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 297     {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT|MON_ONCE, mm_answer_audit_command},
 298 #endif
 299 #endif /* WITH_SSH1 */
 300     {0, 0, NULL}
 301 };
 302
 303 struct mon_table *mon_dispatch;
 304
 305 /* Specifies if a certain message is allowed at the moment */
 306
 307 static void
 308 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit)
 309 {
 310         while (ent->f != NULL) {
 311                 if (ent->type == type) {
 312                         ent->flags &= ~MON_PERMIT;
 313                         ent->flags |= permit ? MON_PERMIT : 0;
 314                         return;
 315                 }
 316                 ent++;
 317         }
 318 }
 319
 320 static void
 321 monitor_permit_authentications(int permit)
 322 {
 323         struct mon_table *ent = mon_dispatch;
 324
 325         while (ent->f != NULL) {
 326                 if (ent->flags & MON_AUTH) {
 327                         ent->flags &= ~MON_PERMIT;
 328                         ent->flags |= permit ? MON_PERMIT : 0;
 329                 }
 330                 ent++;
 331         }
 332 }
 333
 334 void
 335 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
 336 {
 337         struct mon_table *ent;
 338         int authenticated = 0, partial = 0;
 339
 340         debug3("preauth child monitor started");
 341
 342         close(pmonitor->m_recvfd);
 343         close(pmonitor->m_log_sendfd);
 344         pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1;
 345
 346         authctxt = _authctxt;
 347         memset(authctxt, 0, sizeof(*authctxt));
 348
 349         authctxt->loginmsg = &loginmsg;
 350
 351         if (compat20) {
 352                 mon_dispatch = mon_dispatch_proto20;
 353
 354                 /* Permit requests for moduli and signatures */
 355                 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 356                 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 357         } else {
 358                 mon_dispatch = mon_dispatch_proto15;
 359
 360                 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1);
 361         }
 362
 363         /* The first few requests do not require asynchronous access */
 364         while (!authenticated) {
 365                 partial = 0;
 366                 auth_method = "unknown";
 367                 auth_submethod = NULL;
 368                 authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1);
 369
 370                 /* Special handling for multiple required authentications */
 371                 if (options.num_auth_methods != 0) {
 372                         if (!compat20)
 373                                 fatal("AuthenticationMethods is not supported"
 374                                     "with SSH protocol 1");
 375                         if (authenticated &&
 376                             !auth2_update_methods_lists(authctxt,
 377                             auth_method, auth_submethod)) {
 378                                 debug3("%s: method %s: partial", __func__,
 379                                     auth_method);
 380                                 authenticated = 0;
 381                                 partial = 1;
 382                         }
 383                 }
 384
 385                 if (authenticated) {
 386                         if (!(ent->flags & MON_AUTHDECIDE))
 387                                 fatal("%s: unexpected authentication from %d",
 388                                     __func__, ent->type);
 389                         if (authctxt->pw->pw_uid == 0 &&
 390                             !auth_root_allowed(auth_method))
 391                                 authenticated = 0;
 392 #ifdef USE_PAM
 393                         /* PAM needs to perform account checks after auth */
 394                         if (options.use_pam && authenticated) {
 395                                 Buffer m;
 396
 397                                 buffer_init(&m);
 398                                 mm_request_receive_expect(pmonitor->m_sendfd,
 399                                     MONITOR_REQ_PAM_ACCOUNT, &m);
 400                                 authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m);
 401                                 buffer_free(&m);
 402                         }
 403 #endif
 404                 }
 405                 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
 406                         auth_log(authctxt, authenticated, partial,
 407                             auth_method, auth_submethod);
 408                         if (!partial && !authenticated)
 409                                 authctxt->failures++;
 410                 }
 411         }
 412
 413         if (!authctxt->valid)
 414                 fatal("%s: authenticated invalid user", __func__);
 415         if (strcmp(auth_method, "unknown") == 0)
 416                 fatal("%s: authentication method name unknown", __func__);
 417
 418         debug("%s: %s has been authenticated by privileged process",
 419             __func__, authctxt->user);
 420
 421         mm_get_keystate(pmonitor);
 422
 423         /* Drain any buffered messages from the child */
 424         while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0)
 425                 ;
 426
 427         close(pmonitor->m_sendfd);
 428         close(pmonitor->m_log_recvfd);
 429         pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1;
 430 }
 431
 432 static void
 433 monitor_set_child_handler(pid_t pid)
 434 {
 435         monitor_child_pid = pid;
 436 }
 437
 438 static void
 439 monitor_child_handler(int sig)
 440 {
 441         kill(monitor_child_pid, sig);
 442 }
 443
 444 void
 445 monitor_child_postauth(struct monitor *pmonitor)
 446 {
 447         close(pmonitor->m_recvfd);
 448         pmonitor->m_recvfd = -1;
 449
 450         monitor_set_child_handler(pmonitor->m_pid);
 451         signal(SIGHUP, &monitor_child_handler);
 452         signal(SIGTERM, &monitor_child_handler);
 453         signal(SIGINT, &monitor_child_handler);
 454 #ifdef SIGXFSZ
 455         signal(SIGXFSZ, SIG_IGN);
 456 #endif
 457
 458         if (compat20) {
 459                 mon_dispatch = mon_dispatch_postauth20;
 460
 461                 /* Permit requests for moduli and signatures */
 462                 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 463                 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 464                 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
 465         } else {
 466                 mon_dispatch = mon_dispatch_postauth15;
 467                 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
 468         }
 469         if (!no_pty_flag) {
 470                 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
 471                 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1);
 472         }
 473
 474         for (;;)
 475                 monitor_read(pmonitor, mon_dispatch, NULL);
 476 }
 477
 478 void
 479 monitor_sync(struct monitor *pmonitor)
 480 {
 481         if (options.compression) {
 482                 /* The member allocation is not visible, so sync it */
 483                 mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback);
 484         }
 485 }
 486
 487 /* Allocation functions for zlib */
 488 static void *
 489 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size)
 490 {
 491         if (size == 0 || ncount == 0 || ncount > SIZE_MAX / size)
 492                 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size);
 493
 494         return mm_malloc(mm, size * ncount);
 495 }
 496
 497 static void
 498 mm_zfree(struct mm_master *mm, void *address)
 499 {
 500         mm_free(mm, address);
 501 }
 502
 503 static int
 504 monitor_read_log(struct monitor *pmonitor)
 505 {
 506         Buffer logmsg;
 507         u_int len, level;
 508         char *msg;
 509
 510         buffer_init(&logmsg);
 511
 512         /* Read length */
 513         buffer_append_space(&logmsg, 4);
 514         if (atomicio(read, pmonitor->m_log_recvfd,
 515             buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) {
 516                 if (errno == EPIPE) {
 517                         buffer_free(&logmsg);
 518                         debug("%s: child log fd closed", __func__);
 519                         close(pmonitor->m_log_recvfd);
 520                         pmonitor->m_log_recvfd = -1;
 521                         return -1;
 522                 }
 523                 fatal("%s: log fd read: %s", __func__, strerror(errno));
 524         }
 525         len = buffer_get_int(&logmsg);
 526         if (len <= 4 || len > 8192)
 527                 fatal("%s: invalid log message length %u", __func__, len);
 528
 529         /* Read severity, message */
 530         buffer_clear(&logmsg);
 531         buffer_append_space(&logmsg, len);
 532         if (atomicio(read, pmonitor->m_log_recvfd,
 533             buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg))
 534                 fatal("%s: log fd read: %s", __func__, strerror(errno));
 535
 536         /* Log it */
 537         level = buffer_get_int(&logmsg);
 538         msg = buffer_get_string(&logmsg, NULL);
 539         if (log_level_name(level) == NULL)
 540                 fatal("%s: invalid log level %u (corrupted message?)",
 541                     __func__, level);
 542         do_log2(level, "%s [preauth]", msg);
 543
 544         buffer_free(&logmsg);
 545         free(msg);
 546
 547         return 0;
 548 }
 549
 550 int
 551 monitor_read(struct monitor *pmonitor, struct mon_table *ent,
 552     struct mon_table **pent)
 553 {
 554         Buffer m;
 555         int ret;
 556         u_char type;
 557         struct pollfd pfd[2];
 558
 559         for (;;) {
 560                 memset(&pfd, 0, sizeof(pfd));
 561                 pfd[0].fd = pmonitor->m_sendfd;
 562                 pfd[0].events = POLLIN;
 563                 pfd[1].fd = pmonitor->m_log_recvfd;
 564                 pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN;
 565                 if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) {
 566                         if (errno == EINTR || errno == EAGAIN)
 567                                 continue;
 568                         fatal("%s: poll: %s", __func__, strerror(errno));
 569                 }
 570                 if (pfd[1].revents) {
 571                         /*
 572                          * Drain all log messages before processing next
 573                          * monitor request.
 574                          */
 575                         monitor_read_log(pmonitor);
 576                         continue;
 577                 }
 578                 if (pfd[0].revents)
 579                         break;  /* Continues below */
 580         }
 581
 582         buffer_init(&m);
 583
 584         mm_request_receive(pmonitor->m_sendfd, &m);
 585         type = buffer_get_char(&m);
 586
 587         debug3("%s: checking request %d", __func__, type);
 588
 589         while (ent->f != NULL) {
 590                 if (ent->type == type)
 591                         break;
 592                 ent++;
 593         }
 594
 595         if (ent->f != NULL) {
 596                 if (!(ent->flags & MON_PERMIT))
 597                         fatal("%s: unpermitted request %d", __func__,
 598                             type);
 599                 ret = (*ent->f)(pmonitor->m_sendfd, &m);
 600                 buffer_free(&m);
 601
 602                 /* The child may use this request only once, disable it */
 603                 if (ent->flags & MON_ONCE) {
 604                         debug2("%s: %d used once, disabling now", __func__,
 605                             type);
 606                         ent->flags &= ~MON_PERMIT;
 607                 }
 608
 609                 if (pent != NULL)
 610                         *pent = ent;
 611
 612                 return ret;
 613         }
 614
 615         fatal("%s: unsupported request: %d", __func__, type);
 616
 617         /* NOTREACHED */
 618         return (-1);
 619 }
 620
 621 /* allowed key state */
 622 static int
 623 monitor_allowed_key(u_char *blob, u_int bloblen)
 624 {
 625         /* make sure key is allowed */
 626         if (key_blob == NULL || key_bloblen != bloblen ||
 627             timingsafe_bcmp(key_blob, blob, key_bloblen))
 628                 return (0);
 629         return (1);
 630 }
 631
 632 static void
 633 monitor_reset_key_state(void)
 634 {
 635         /* reset state */
 636         free(key_blob);
 637         free(hostbased_cuser);
 638         free(hostbased_chost);
 639         key_blob = NULL;
 640         key_bloblen = 0;
 641         key_blobtype = MM_NOKEY;
 642         hostbased_cuser = NULL;
 643         hostbased_chost = NULL;
 644 }
 645
 646 #ifdef WITH_OPENSSL
 647 int
 648 mm_answer_moduli(int sock, Buffer *m)
 649 {
 650         DH *dh;
 651         int min, want, max;
 652
 653         min = buffer_get_int(m);
 654         want = buffer_get_int(m);
 655         max = buffer_get_int(m);
 656
 657         debug3("%s: got parameters: %d %d %d",
 658             __func__, min, want, max);
 659         /* We need to check here, too, in case the child got corrupted */
 660         if (max < min || want < min || max < want)
 661                 fatal("%s: bad parameters: %d %d %d",
 662                     __func__, min, want, max);
 663
 664         buffer_clear(m);
 665
 666         dh = choose_dh(min, want, max);
 667         if (dh == NULL) {
 668                 buffer_put_char(m, 0);
 669                 return (0);
 670         } else {
 671                 /* Send first bignum */
 672                 buffer_put_char(m, 1);
 673                 buffer_put_bignum2(m, dh->p);
 674                 buffer_put_bignum2(m, dh->g);
 675
 676                 DH_free(dh);
 677         }
 678         mm_request_send(sock, MONITOR_ANS_MODULI, m);
 679         return (0);
 680 }
 681 #endif
 682
 683 int
 684 mm_answer_sign(int sock, Buffer *m)
 685 {
 686         struct ssh *ssh = active_state;         /* XXX */
 687         extern int auth_sock;                   /* XXX move to state struct? */
 688         struct sshkey *key;
 689         struct sshbuf *sigbuf = NULL;
 690         u_char *p = NULL, *signature = NULL;
 691         char *alg = NULL;
 692         size_t datlen, siglen, alglen;
 693         int r, is_proof = 0;
 694         u_int keyid;
 695         const char proof_req[] = "hostkeys-prove-00@openssh.com";
 696
 697         debug3("%s", __func__);
 698
 699         if ((r = sshbuf_get_u32(m, &keyid)) != 0 ||
 700             (r = sshbuf_get_string(m, &p, &datlen)) != 0 ||
 701             (r = sshbuf_get_cstring(m, &alg, &alglen)) != 0)
 702                 fatal("%s: buffer error: %s", __func__, ssh_err(r));
 703         if (keyid > INT_MAX)
 704                 fatal("%s: invalid key ID", __func__);
 705
 706         /*
 707          * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes),
 708          * SHA384 (48 bytes) and SHA512 (64 bytes).
 709          *
 710          * Otherwise, verify the signature request is for a hostkey
 711          * proof.
 712          *
 713          * XXX perform similar check for KEX signature requests too?
 714          * it's not trivial, since what is signed is the hash, rather
 715          * than the full kex structure...
 716          */
 717         if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64) {
 718                 /*
 719                  * Construct expected hostkey proof and compare it to what
 720                  * the client sent us.
 721                  */
 722                 if (session_id2_len == 0) /* hostkeys is never first */
 723                         fatal("%s: bad data length: %zu", __func__, datlen);
 724                 if ((key = get_hostkey_public_by_index(keyid, ssh)) == NULL)
 725                         fatal("%s: no hostkey for index %d", __func__, keyid);
 726                 if ((sigbuf = sshbuf_new()) == NULL)
 727                         fatal("%s: sshbuf_new", __func__);
 728                 if ((r = sshbuf_put_cstring(sigbuf, proof_req)) != 0 ||
 729                     (r = sshbuf_put_string(sigbuf, session_id2,
 730                     session_id2_len)) != 0 ||
 731                     (r = sshkey_puts(key, sigbuf)) != 0)
 732                         fatal("%s: couldn't prepare private key "
 733                             "proof buffer: %s", __func__, ssh_err(r));
 734                 if (datlen != sshbuf_len(sigbuf) ||
 735                     memcmp(p, sshbuf_ptr(sigbuf), sshbuf_len(sigbuf)) != 0)
 736                         fatal("%s: bad data length: %zu, hostkey proof len %zu",
 737                             __func__, datlen, sshbuf_len(sigbuf));
 738                 sshbuf_free(sigbuf);
 739                 is_proof = 1;
 740         }
 741
 742         /* save session id, it will be passed on the first call */
 743         if (session_id2_len == 0) {
 744                 session_id2_len = datlen;
 745                 session_id2 = xmalloc(session_id2_len);
 746                 memcpy(session_id2, p, session_id2_len);
 747         }
 748
 749         if ((key = get_hostkey_by_index(keyid)) != NULL) {
 750                 if ((r = sshkey_sign(key, &signature, &siglen, p, datlen, alg,
 751                     datafellows)) != 0)
 752                         fatal("%s: sshkey_sign failed: %s",
 753                             __func__, ssh_err(r));
 754         } else if ((key = get_hostkey_public_by_index(keyid, ssh)) != NULL &&
 755             auth_sock > 0) {
 756                 if ((r = ssh_agent_sign(auth_sock, key, &signature, &siglen,
 757                     p, datlen, alg, datafellows)) != 0) {
 758                         fatal("%s: ssh_agent_sign failed: %s",
 759                             __func__, ssh_err(r));
 760                 }
 761         } else
 762                 fatal("%s: no hostkey from index %d", __func__, keyid);
 763
 764         debug3("%s: %s signature %p(%zu)", __func__,
 765             is_proof ? "KEX" : "hostkey proof", signature, siglen);
 766
 767         sshbuf_reset(m);
 768         if ((r = sshbuf_put_string(m, signature, siglen)) != 0)
 769                 fatal("%s: buffer error: %s", __func__, ssh_err(r));
 770
 771         free(alg);
 772         free(p);
 773         free(signature);
 774
 775         mm_request_send(sock, MONITOR_ANS_SIGN, m);
 776
 777         /* Turn on permissions for getpwnam */
 778         monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
 779
 780         return (0);
 781 }
 782
 783 /* Retrieves the password entry and also checks if the user is permitted */
 784
 785 int
 786 mm_answer_pwnamallow(int sock, Buffer *m)
 787 {
 788         char *username;
 789         struct passwd *pwent;
 790         int allowed = 0;
 791         u_int i;
 792
 793         debug3("%s", __func__);
 794
 795         if (authctxt->attempt++ != 0)
 796                 fatal("%s: multiple attempts for getpwnam", __func__);
 797
 798         username = buffer_get_string(m, NULL);
 799
 800         pwent = getpwnamallow(username);
 801
 802         authctxt->user = xstrdup(username);
 803         setproctitle("%s [priv]", pwent ? username : "unknown");
 804         free(username);
 805
 806         buffer_clear(m);
 807
 808         if (pwent == NULL) {
 809                 buffer_put_char(m, 0);
 810                 authctxt->pw = fakepw();
 811                 goto out;
 812         }
 813
 814         allowed = 1;
 815         authctxt->pw = pwent;
 816         authctxt->valid = 1;
 817
 818         buffer_put_char(m, 1);
 819         buffer_put_string(m, pwent, sizeof(struct passwd));
 820         buffer_put_cstring(m, pwent->pw_name);
 821         buffer_put_cstring(m, "*");
 822 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
 823         buffer_put_cstring(m, pwent->pw_gecos);
 824 #endif
 825 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
 826         buffer_put_cstring(m, pwent->pw_class);
 827 #endif
 828         buffer_put_cstring(m, pwent->pw_dir);
 829         buffer_put_cstring(m, pwent->pw_shell);
 830
 831  out:
 832         buffer_put_string(m, &options, sizeof(options));
 833
 834 #define M_CP_STROPT(x) do { \
 835                 if (options.x != NULL) \
 836                         buffer_put_cstring(m, options.x); \
 837         } while (0)
 838 #define M_CP_STRARRAYOPT(x, nx) do { \
 839                 for (i = 0; i < options.nx; i++) \
 840                         buffer_put_cstring(m, options.x[i]); \
 841         } while (0)
 842         /* See comment in servconf.h */
 843         COPY_MATCH_STRING_OPTS();
 844 #undef M_CP_STROPT
 845 #undef M_CP_STRARRAYOPT
 846
 847         /* Create valid auth method lists */
 848         if (compat20 && auth2_setup_methods_lists(authctxt) != 0) {
 849                 /*
 850                  * The monitor will continue long enough to let the child
 851                  * run to it's packet_disconnect(), but it must not allow any
 852                  * authentication to succeed.
 853                  */
 854                 debug("%s: no valid authentication method lists", __func__);
 855         }
 856
 857         debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed);
 858         mm_request_send(sock, MONITOR_ANS_PWNAM, m);
 859
 860         /* For SSHv1 allow authentication now */
 861         if (!compat20)
 862                 monitor_permit_authentications(1);
 863         else {
 864                 /* Allow service/style information on the auth context */
 865                 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
 866                 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
 867         }
 868 #ifdef USE_PAM
 869         if (options.use_pam)
 870                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
 871 #endif
 872
 873         return (0);
 874 }
 875
 876 int mm_answer_auth2_read_banner(int sock, Buffer *m)
 877 {
 878         char *banner;
 879
 880         buffer_clear(m);
 881         banner = auth2_read_banner();
 882         buffer_put_cstring(m, banner != NULL ? banner : "");
 883         mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m);
 884         free(banner);
 885
 886         return (0);
 887 }
 888
 889 int
 890 mm_answer_authserv(int sock, Buffer *m)
 891 {
 892         monitor_permit_authentications(1);
 893
 894         authctxt->service = buffer_get_string(m, NULL);
 895         authctxt->style = buffer_get_string(m, NULL);
 896         debug3("%s: service=%s, style=%s",
 897             __func__, authctxt->service, authctxt->style);
 898
 899         if (strlen(authctxt->style) == 0) {
 900                 free(authctxt->style);
 901                 authctxt->style = NULL;
 902         }
 903
 904         return (0);
 905 }
 906
 907 int
 908 mm_answer_authpassword(int sock, Buffer *m)
 909 {
 910         static int call_count;
 911         char *passwd;
 912         int authenticated;
 913         u_int plen;
 914
 915         passwd = buffer_get_string(m, &plen);
 916         /* Only authenticate if the context is valid */
 917         authenticated = options.password_authentication &&
 918             auth_password(authctxt, passwd);
 919         explicit_bzero(passwd, strlen(passwd));
 920         free(passwd);
 921
 922         buffer_clear(m);
 923         buffer_put_int(m, authenticated);
 924 #ifdef USE_PAM
 925         buffer_put_int(m, sshpam_get_maxtries_reached());
 926 #endif
 927
 928         debug3("%s: sending result %d", __func__, authenticated);
 929         mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m);
 930
 931         call_count++;
 932         if (plen == 0 && call_count == 1)
 933                 auth_method = "none";
 934         else
 935                 auth_method = "password";
 936
 937         /* Causes monitor loop to terminate if authenticated */
 938         return (authenticated);
 939 }
 940
 941 #ifdef BSD_AUTH
 942 int
 943 mm_answer_bsdauthquery(int sock, Buffer *m)
 944 {
 945         char *name, *infotxt;
 946         u_int numprompts;
 947         u_int *echo_on;
 948         char **prompts;
 949         u_int success;
 950
 951         success = bsdauth_query(authctxt, &name, &infotxt, &numprompts,
 952             &prompts, &echo_on) < 0 ? 0 : 1;
 953
 954         buffer_clear(m);
 955         buffer_put_int(m, success);
 956         if (success)
 957                 buffer_put_cstring(m, prompts[0]);
 958
 959         debug3("%s: sending challenge success: %u", __func__, success);
 960         mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m);
 961
 962         if (success) {
 963                 free(name);
 964                 free(infotxt);
 965                 free(prompts);
 966                 free(echo_on);
 967         }
 968
 969         return (0);
 970 }
 971
 972 int
 973 mm_answer_bsdauthrespond(int sock, Buffer *m)
 974 {
 975         char *response;
 976         int authok;
 977
 978         if (authctxt->as == NULL)
 979                 fatal("%s: no bsd auth session", __func__);
 980
 981         response = buffer_get_string(m, NULL);
 982         authok = options.challenge_response_authentication &&
 983             auth_userresponse(authctxt->as, response, 0);
 984         authctxt->as = NULL;
 985         debug3("%s: <%s> = <%d>", __func__, response, authok);
 986         free(response);
 987
 988         buffer_clear(m);
 989         buffer_put_int(m, authok);
 990
 991         debug3("%s: sending authenticated: %d", __func__, authok);
 992         mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
 993
 994         if (compat20) {
 995                 auth_method = "keyboard-interactive";
 996                 auth_submethod = "bsdauth";
 997         } else
 998                 auth_method = "bsdauth";
 999
1000         return (authok != 0);
1001 }
1002 #endif
1003
1004 #ifdef SKEY
1005 int
1006 mm_answer_skeyquery(int sock, Buffer *m)
1007 {
1008         struct skey skey;
1009         char challenge[1024];
1010         u_int success;
1011
1012         success = _compat_skeychallenge(&skey, authctxt->user, challenge,
1013             sizeof(challenge)) < 0 ? 0 : 1;
1014
1015         buffer_clear(m);
1016         buffer_put_int(m, success);
1017         if (success)
1018                 buffer_put_cstring(m, challenge);
1019
1020         debug3("%s: sending challenge success: %u", __func__, success);
1021         mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m);
1022
1023         return (0);
1024 }
1025
1026 int
1027 mm_answer_skeyrespond(int sock, Buffer *m)
1028 {
1029         char *response;
1030         int authok;
1031
1032         response = buffer_get_string(m, NULL);
1033
1034         authok = (options.challenge_response_authentication &&
1035             authctxt->valid &&
1036             skey_haskey(authctxt->pw->pw_name) == 0 &&
1037             skey_passcheck(authctxt->pw->pw_name, response) != -1);
1038
1039         free(response);
1040
1041         buffer_clear(m);
1042         buffer_put_int(m, authok);
1043
1044         debug3("%s: sending authenticated: %d", __func__, authok);
1045         mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m);
1046
1047         auth_method = "keyboard-interactive";
1048         auth_submethod = "skey";
1049
1050         return (authok != 0);
1051 }
1052 #endif
1053
1054 #ifdef USE_PAM
1055 int
1056 mm_answer_pam_start(int sock, Buffer *m)
1057 {
1058         if (!options.use_pam)
1059                 fatal("UsePAM not set, but ended up in %s anyway", __func__);
1060
1061         start_pam(authctxt);
1062
1063         monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1);
1064
1065         return (0);
1066 }
1067
1068 int
1069 mm_answer_pam_account(int sock, Buffer *m)
1070 {
1071         u_int ret;
1072
1073         if (!options.use_pam)
1074                 fatal("UsePAM not set, but ended up in %s anyway", __func__);
1075
1076         ret = do_pam_account();
1077
1078         buffer_put_int(m, ret);
1079         buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
1080
1081         mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m);
1082
1083         return (ret);
1084 }
1085
1086 static void *sshpam_ctxt, *sshpam_authok;
1087 extern KbdintDevice sshpam_device;
1088
1089 int
1090 mm_answer_pam_init_ctx(int sock, Buffer *m)
1091 {
1092         debug3("%s", __func__);
1093         sshpam_ctxt = (sshpam_device.init_ctx)(authctxt);
1094         sshpam_authok = NULL;
1095         buffer_clear(m);
1096         if (sshpam_ctxt != NULL) {
1097                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
1098                 buffer_put_int(m, 1);
1099         } else {
1100                 buffer_put_int(m, 0);
1101         }
1102         mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m);
1103         return (0);
1104 }
1105
1106 int
1107 mm_answer_pam_query(int sock, Buffer *m)
1108 {
1109         char *name = NULL, *info = NULL, **prompts = NULL;
1110         u_int i, num = 0, *echo_on = 0;
1111         int ret;
1112
1113         debug3("%s", __func__);
1114         sshpam_authok = NULL;
1115         ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, &num, &prompts, &echo_on);
1116         if (ret == 0 && num == 0)
1117                 sshpam_authok = sshpam_ctxt;
1118         if (num > 1 || name == NULL || info == NULL)
1119                 ret = -1;
1120         buffer_clear(m);
1121         buffer_put_int(m, ret);
1122         buffer_put_cstring(m, name);
1123         free(name);
1124         buffer_put_cstring(m, info);
1125         free(info);
1126         buffer_put_int(m, sshpam_get_maxtries_reached());
1127         buffer_put_int(m, num);
1128         for (i = 0; i < num; ++i) {
1129                 buffer_put_cstring(m, prompts[i]);
1130                 free(prompts[i]);
1131                 buffer_put_int(m, echo_on[i]);
1132         }
1133         free(prompts);
1134         free(echo_on);
1135         auth_method = "keyboard-interactive";
1136         auth_submethod = "pam";
1137         mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m);
1138         return (0);
1139 }
1140
1141 int
1142 mm_answer_pam_respond(int sock, Buffer *m)
1143 {
1144         char **resp;
1145         u_int i, num;
1146         int ret;
1147
1148         debug3("%s", __func__);
1149         sshpam_authok = NULL;
1150         num = buffer_get_int(m);
1151         if (num > 0) {
1152                 resp = xcalloc(num, sizeof(char *));
1153                 for (i = 0; i < num; ++i)
1154                         resp[i] = buffer_get_string(m, NULL);
1155                 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp);
1156                 for (i = 0; i < num; ++i)
1157                         free(resp[i]);
1158                 free(resp);
1159         } else {
1160                 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL);
1161         }
1162         buffer_clear(m);
1163         buffer_put_int(m, ret);
1164         mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m);
1165         auth_method = "keyboard-interactive";
1166         auth_submethod = "pam";
1167         if (ret == 0)
1168                 sshpam_authok = sshpam_ctxt;
1169         return (0);
1170 }
1171
1172 int
1173 mm_answer_pam_free_ctx(int sock, Buffer *m)
1174 {
1175         int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt;
1176
1177         debug3("%s", __func__);
1178         (sshpam_device.free_ctx)(sshpam_ctxt);
1179         sshpam_ctxt = sshpam_authok = NULL;
1180         buffer_clear(m);
1181         mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m);
1182         auth_method = "keyboard-interactive";
1183         auth_submethod = "pam";
1184         return r;
1185 }
1186 #endif
1187
1188 int
1189 mm_answer_keyallowed(int sock, Buffer *m)
1190 {
1191         Key *key;
1192         char *cuser, *chost;
1193         u_char *blob;
1194         u_int bloblen, pubkey_auth_attempt;
1195         enum mm_keytype type = 0;
1196         int allowed = 0;
1197
1198         debug3("%s entering", __func__);
1199
1200         type = buffer_get_int(m);
1201         cuser = buffer_get_string(m, NULL);
1202         chost = buffer_get_string(m, NULL);
1203         blob = buffer_get_string(m, &bloblen);
1204         pubkey_auth_attempt = buffer_get_int(m);
1205
1206         key = key_from_blob(blob, bloblen);
1207
1208         if ((compat20 && type == MM_RSAHOSTKEY) ||
1209             (!compat20 && type != MM_RSAHOSTKEY))
1210                 fatal("%s: key type and protocol mismatch", __func__);
1211
1212         debug3("%s: key_from_blob: %p", __func__, key);
1213
1214         if (key != NULL && authctxt->valid) {
1215                 /* These should not make it past the privsep child */
1216                 if (key_type_plain(key->type) == KEY_RSA &&
1217                     (datafellows & SSH_BUG_RSASIGMD5) != 0)
1218                         fatal("%s: passed a SSH_BUG_RSASIGMD5 key", __func__);
1219
1220                 switch (type) {
1221                 case MM_USERKEY:
1222                         allowed = options.pubkey_authentication &&
1223                             !auth2_userkey_already_used(authctxt, key) &&
1224                             match_pattern_list(sshkey_ssh_name(key),
1225                             options.pubkey_key_types, 0) == 1 &&
1226                             user_key_allowed(authctxt->pw, key,
1227                             pubkey_auth_attempt);
1228                         pubkey_auth_info(authctxt, key, NULL);
1229                         auth_method = "publickey";
1230                         if (options.pubkey_authentication &&
1231                             (!pubkey_auth_attempt || allowed != 1))
1232                                 auth_clear_options();
1233                         break;
1234                 case MM_HOSTKEY:
1235                         allowed = options.hostbased_authentication &&
1236                             match_pattern_list(sshkey_ssh_name(key),
1237                             options.hostbased_key_types, 0) == 1 &&
1238                             hostbased_key_allowed(authctxt->pw,
1239                             cuser, chost, key);
1240                         pubkey_auth_info(authctxt, key,
1241                             "client user \"%.100s\", client host \"%.100s\"",
1242                             cuser, chost);
1243                         auth_method = "hostbased";
1244                         break;
1245 #ifdef WITH_SSH1
1246                 case MM_RSAHOSTKEY:
1247                         key->type = KEY_RSA1; /* XXX */
1248                         allowed = options.rhosts_rsa_authentication &&
1249                             auth_rhosts_rsa_key_allowed(authctxt->pw,
1250                             cuser, chost, key);
1251                         if (options.rhosts_rsa_authentication && allowed != 1)
1252                                 auth_clear_options();
1253                         auth_method = "rsa";
1254                         break;
1255 #endif
1256                 default:
1257                         fatal("%s: unknown key type %d", __func__, type);
1258                         break;
1259                 }
1260         }
1261
1262         debug3("%s: key %p is %s",
1263             __func__, key, allowed ? "allowed" : "not allowed");
1264
1265         if (key != NULL)
1266                 key_free(key);
1267
1268         /* clear temporarily storage (used by verify) */
1269         monitor_reset_key_state();
1270
1271         if (allowed) {
1272                 /* Save temporarily for comparison in verify */
1273                 key_blob = blob;
1274                 key_bloblen = bloblen;
1275                 key_blobtype = type;
1276                 hostbased_cuser = cuser;
1277                 hostbased_chost = chost;
1278         } else {
1279                 /* Log failed attempt */
1280                 auth_log(authctxt, 0, 0, auth_method, NULL);
1281                 free(blob);
1282                 free(cuser);
1283                 free(chost);
1284         }
1285
1286         buffer_clear(m);
1287         buffer_put_int(m, allowed);
1288         buffer_put_int(m, forced_command != NULL);
1289
1290         mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m);
1291
1292         if (type == MM_RSAHOSTKEY)
1293                 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1294
1295         return (0);
1296 }
1297
1298 static int
1299 monitor_valid_userblob(u_char *data, u_int datalen)
1300 {
1301         Buffer b;
1302         u_char *p;
1303         char *userstyle, *cp;
1304         u_int len;
1305         int fail = 0;
1306
1307         buffer_init(&b);
1308         buffer_append(&b, data, datalen);
1309
1310         if (datafellows & SSH_OLD_SESSIONID) {
1311                 p = buffer_ptr(&b);
1312                 len = buffer_len(&b);
1313                 if ((session_id2 == NULL) ||
1314                     (len < session_id2_len) ||
1315                     (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1316                         fail++;
1317                 buffer_consume(&b, session_id2_len);
1318         } else {
1319                 p = buffer_get_string(&b, &len);
1320                 if ((session_id2 == NULL) ||
1321                     (len != session_id2_len) ||
1322                     (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1323                         fail++;
1324                 free(p);
1325         }
1326         if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1327                 fail++;
1328         cp = buffer_get_cstring(&b, NULL);
1329         xasprintf(&userstyle, "%s%s%s", authctxt->user,
1330             authctxt->style ? ":" : "",
1331             authctxt->style ? authctxt->style : "");
1332         if (strcmp(userstyle, cp) != 0) {
1333                 logit("wrong user name passed to monitor: "
1334                     "expected %s != %.100s", userstyle, cp);
1335                 fail++;
1336         }
1337         free(userstyle);
1338         free(cp);
1339         buffer_skip_string(&b);
1340         if (datafellows & SSH_BUG_PKAUTH) {
1341                 if (!buffer_get_char(&b))
1342                         fail++;
1343         } else {
1344                 cp = buffer_get_cstring(&b, NULL);
1345                 if (strcmp("publickey", cp) != 0)
1346                         fail++;
1347                 free(cp);
1348                 if (!buffer_get_char(&b))
1349                         fail++;
1350                 buffer_skip_string(&b);
1351         }
1352         buffer_skip_string(&b);
1353         if (buffer_len(&b) != 0)
1354                 fail++;
1355         buffer_free(&b);
1356         return (fail == 0);
1357 }
1358
1359 static int
1360 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser,
1361     char *chost)
1362 {
1363         Buffer b;
1364         char *p, *userstyle;
1365         u_int len;
1366         int fail = 0;
1367
1368         buffer_init(&b);
1369         buffer_append(&b, data, datalen);
1370
1371         p = buffer_get_string(&b, &len);
1372         if ((session_id2 == NULL) ||
1373             (len != session_id2_len) ||
1374             (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1375                 fail++;
1376         free(p);
1377
1378         if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1379                 fail++;
1380         p = buffer_get_cstring(&b, NULL);
1381         xasprintf(&userstyle, "%s%s%s", authctxt->user,
1382             authctxt->style ? ":" : "",
1383             authctxt->style ? authctxt->style : "");
1384         if (strcmp(userstyle, p) != 0) {
1385                 logit("wrong user name passed to monitor: expected %s != %.100s",
1386                     userstyle, p);
1387                 fail++;
1388         }
1389         free(userstyle);
1390         free(p);
1391         buffer_skip_string(&b); /* service */
1392         p = buffer_get_cstring(&b, NULL);
1393         if (strcmp(p, "hostbased") != 0)
1394                 fail++;
1395         free(p);
1396         buffer_skip_string(&b); /* pkalg */
1397         buffer_skip_string(&b); /* pkblob */
1398
1399         /* verify client host, strip trailing dot if necessary */
1400         p = buffer_get_string(&b, NULL);
1401         if (((len = strlen(p)) > 0) && p[len - 1] == '.')
1402                 p[len - 1] = '\0';
1403         if (strcmp(p, chost) != 0)
1404                 fail++;
1405         free(p);
1406
1407         /* verify client user */
1408         p = buffer_get_string(&b, NULL);
1409         if (strcmp(p, cuser) != 0)
1410                 fail++;
1411         free(p);
1412
1413         if (buffer_len(&b) != 0)
1414                 fail++;
1415         buffer_free(&b);
1416         return (fail == 0);
1417 }
1418
1419 int
1420 mm_answer_keyverify(int sock, Buffer *m)
1421 {
1422         Key *key;
1423         u_char *signature, *data, *blob;
1424         u_int signaturelen, datalen, bloblen;
1425         int verified = 0;
1426         int valid_data = 0;
1427
1428         blob = buffer_get_string(m, &bloblen);
1429         signature = buffer_get_string(m, &signaturelen);
1430         data = buffer_get_string(m, &datalen);
1431
1432         if (hostbased_cuser == NULL || hostbased_chost == NULL ||
1433           !monitor_allowed_key(blob, bloblen))
1434                 fatal("%s: bad key, not previously allowed", __func__);
1435
1436         key = key_from_blob(blob, bloblen);
1437         if (key == NULL)
1438                 fatal("%s: bad public key blob", __func__);
1439
1440         switch (key_blobtype) {
1441         case MM_USERKEY:
1442                 valid_data = monitor_valid_userblob(data, datalen);
1443                 break;
1444         case MM_HOSTKEY:
1445                 valid_data = monitor_valid_hostbasedblob(data, datalen,
1446                     hostbased_cuser, hostbased_chost);
1447                 break;
1448         default:
1449                 valid_data = 0;
1450                 break;
1451         }
1452         if (!valid_data)
1453                 fatal("%s: bad signature data blob", __func__);
1454
1455         verified = key_verify(key, signature, signaturelen, data, datalen);
1456         debug3("%s: key %p signature %s",
1457             __func__, key, (verified == 1) ? "verified" : "unverified");
1458
1459         /* If auth was successful then record key to ensure it isn't reused */
1460         if (verified == 1 && key_blobtype == MM_USERKEY)
1461                 auth2_record_userkey(authctxt, key);
1462         else
1463                 key_free(key);
1464
1465         free(blob);
1466         free(signature);
1467         free(data);
1468
1469         auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased";
1470
1471         monitor_reset_key_state();
1472
1473         buffer_clear(m);
1474         buffer_put_int(m, verified);
1475         mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m);
1476
1477         return (verified == 1);
1478 }
1479
1480 static void
1481 mm_record_login(Session *s, struct passwd *pw)
1482 {
1483         struct ssh *ssh = active_state; /* XXX */
1484         socklen_t fromlen;
1485         struct sockaddr_storage from;
1486
1487         if (options.use_login)
1488                 return;
1489
1490         /*
1491          * Get IP address of client. If the connection is not a socket, let
1492          * the address be 0.0.0.0.
1493          */
1494         memset(&from, 0, sizeof(from));
1495         fromlen = sizeof(from);
1496         if (packet_connection_is_on_socket()) {
1497                 if (getpeername(packet_get_connection_in(),
1498                     (struct sockaddr *)&from, &fromlen) < 0) {
1499                         debug("getpeername: %.100s", strerror(errno));
1500                         cleanup_exit(255);
1501                 }
1502         }
1503         /* Record that there was a login on that tty from the remote host. */
1504         record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
1505             session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns),
1506             (struct sockaddr *)&from, fromlen);
1507 }
1508
1509 static void
1510 mm_session_close(Session *s)
1511 {
1512         debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid);
1513         if (s->ttyfd != -1) {
1514                 debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd);
1515                 session_pty_cleanup2(s);
1516         }
1517         session_unused(s->self);
1518 }
1519
1520 int
1521 mm_answer_pty(int sock, Buffer *m)
1522 {
1523         extern struct monitor *pmonitor;
1524         Session *s;
1525         int res, fd0;
1526
1527         debug3("%s entering", __func__);
1528
1529         buffer_clear(m);
1530         s = session_new();
1531         if (s == NULL)
1532                 goto error;
1533         s->authctxt = authctxt;
1534         s->pw = authctxt->pw;
1535         s->pid = pmonitor->m_pid;
1536         res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
1537         if (res == 0)
1538                 goto error;
1539         pty_setowner(authctxt->pw, s->tty);
1540
1541         buffer_put_int(m, 1);
1542         buffer_put_cstring(m, s->tty);
1543
1544         /* We need to trick ttyslot */
1545         if (dup2(s->ttyfd, 0) == -1)
1546                 fatal("%s: dup2", __func__);
1547
1548         mm_record_login(s, authctxt->pw);
1549
1550         /* Now we can close the file descriptor again */
1551         close(0);
1552
1553         /* send messages generated by record_login */
1554         buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
1555         buffer_clear(&loginmsg);
1556
1557         mm_request_send(sock, MONITOR_ANS_PTY, m);
1558
1559         if (mm_send_fd(sock, s->ptyfd) == -1 ||
1560             mm_send_fd(sock, s->ttyfd) == -1)
1561                 fatal("%s: send fds failed", __func__);
1562
1563         /* make sure nothing uses fd 0 */
1564         if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0)
1565                 fatal("%s: open(/dev/null): %s", __func__, strerror(errno));
1566         if (fd0 != 0)
1567                 error("%s: fd0 %d != 0", __func__, fd0);
1568
1569         /* slave is not needed */
1570         close(s->ttyfd);
1571         s->ttyfd = s->ptyfd;
1572         /* no need to dup() because nobody closes ptyfd */
1573         s->ptymaster = s->ptyfd;
1574
1575         debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd);
1576
1577         return (0);
1578
1579  error:
1580         if (s != NULL)
1581                 mm_session_close(s);
1582         buffer_put_int(m, 0);
1583         mm_request_send(sock, MONITOR_ANS_PTY, m);
1584         return (0);
1585 }
1586
1587 int
1588 mm_answer_pty_cleanup(int sock, Buffer *m)
1589 {
1590         Session *s;
1591         char *tty;
1592
1593         debug3("%s entering", __func__);
1594
1595         tty = buffer_get_string(m, NULL);
1596         if ((s = session_by_tty(tty)) != NULL)
1597                 mm_session_close(s);
1598         buffer_clear(m);
1599         free(tty);
1600         return (0);
1601 }
1602
1603 #ifdef WITH_SSH1
1604 int
1605 mm_answer_sesskey(int sock, Buffer *m)
1606 {
1607         BIGNUM *p;
1608         int rsafail;
1609
1610         /* Turn off permissions */
1611         monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0);
1612
1613         if ((p = BN_new()) == NULL)
1614                 fatal("%s: BN_new", __func__);
1615
1616         buffer_get_bignum2(m, p);
1617
1618         rsafail = ssh1_session_key(p);
1619
1620         buffer_clear(m);
1621         buffer_put_int(m, rsafail);
1622         buffer_put_bignum2(m, p);
1623
1624         BN_clear_free(p);
1625
1626         mm_request_send(sock, MONITOR_ANS_SESSKEY, m);
1627
1628         /* Turn on permissions for sessid passing */
1629         monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1);
1630
1631         return (0);
1632 }
1633
1634 int
1635 mm_answer_sessid(int sock, Buffer *m)
1636 {
1637         int i;
1638
1639         debug3("%s entering", __func__);
1640
1641         if (buffer_len(m) != 16)
1642                 fatal("%s: bad ssh1 session id", __func__);
1643         for (i = 0; i < 16; i++)
1644                 session_id[i] = buffer_get_char(m);
1645
1646         /* Turn on permissions for getpwnam */
1647         monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
1648
1649         return (0);
1650 }
1651
1652 int
1653 mm_answer_rsa_keyallowed(int sock, Buffer *m)
1654 {
1655         BIGNUM *client_n;
1656         Key *key = NULL;
1657         u_char *blob = NULL;
1658         u_int blen = 0;
1659         int allowed = 0;
1660
1661         debug3("%s entering", __func__);
1662
1663         auth_method = "rsa";
1664         if (options.rsa_authentication && authctxt->valid) {
1665                 if ((client_n = BN_new()) == NULL)
1666                         fatal("%s: BN_new", __func__);
1667                 buffer_get_bignum2(m, client_n);
1668                 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key);
1669                 BN_clear_free(client_n);
1670         }
1671         buffer_clear(m);
1672         buffer_put_int(m, allowed);
1673         buffer_put_int(m, forced_command != NULL);
1674
1675         /* clear temporarily storage (used by generate challenge) */
1676         monitor_reset_key_state();
1677
1678         if (allowed && key != NULL) {
1679                 key->type = KEY_RSA;    /* cheat for key_to_blob */
1680                 if (key_to_blob(key, &blob, &blen) == 0)
1681                         fatal("%s: key_to_blob failed", __func__);
1682                 buffer_put_string(m, blob, blen);
1683
1684                 /* Save temporarily for comparison in verify */
1685                 key_blob = blob;
1686                 key_bloblen = blen;
1687                 key_blobtype = MM_RSAUSERKEY;
1688         }
1689         if (key != NULL)
1690                 key_free(key);
1691
1692         mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m);
1693
1694         monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1695         monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0);
1696         return (0);
1697 }
1698
1699 int
1700 mm_answer_rsa_challenge(int sock, Buffer *m)
1701 {
1702         Key *key = NULL;
1703         u_char *blob;
1704         u_int blen;
1705
1706         debug3("%s entering", __func__);
1707
1708         if (!authctxt->valid)
1709                 fatal("%s: authctxt not valid", __func__);
1710         blob = buffer_get_string(m, &blen);
1711         if (!monitor_allowed_key(blob, blen))
1712                 fatal("%s: bad key, not previously allowed", __func__);
1713         if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1714                 fatal("%s: key type mismatch", __func__);
1715         if ((key = key_from_blob(blob, blen)) == NULL)
1716                 fatal("%s: received bad key", __func__);
1717         if (key->type != KEY_RSA)
1718                 fatal("%s: received bad key type %d", __func__, key->type);
1719         key->type = KEY_RSA1;
1720         if (ssh1_challenge)
1721                 BN_clear_free(ssh1_challenge);
1722         ssh1_challenge = auth_rsa_generate_challenge(key);
1723
1724         buffer_clear(m);
1725         buffer_put_bignum2(m, ssh1_challenge);
1726
1727         debug3("%s sending reply", __func__);
1728         mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m);
1729
1730         monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1);
1731
1732         free(blob);
1733         key_free(key);
1734         return (0);
1735 }
1736
1737 int
1738 mm_answer_rsa_response(int sock, Buffer *m)
1739 {
1740         Key *key = NULL;
1741         u_char *blob, *response;
1742         u_int blen, len;
1743         int success;
1744
1745         debug3("%s entering", __func__);
1746
1747         if (!authctxt->valid)
1748                 fatal("%s: authctxt not valid", __func__);
1749         if (ssh1_challenge == NULL)
1750                 fatal("%s: no ssh1_challenge", __func__);
1751
1752         blob = buffer_get_string(m, &blen);
1753         if (!monitor_allowed_key(blob, blen))
1754                 fatal("%s: bad key, not previously allowed", __func__);
1755         if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1756                 fatal("%s: key type mismatch: %d", __func__, key_blobtype);
1757         if ((key = key_from_blob(blob, blen)) == NULL)
1758                 fatal("%s: received bad key", __func__);
1759         response = buffer_get_string(m, &len);
1760         if (len != 16)
1761                 fatal("%s: received bad response to challenge", __func__);
1762         success = auth_rsa_verify_response(key, ssh1_challenge, response);
1763
1764         free(blob);
1765         key_free(key);
1766         free(response);
1767
1768         auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa";
1769
1770         /* reset state */
1771         BN_clear_free(ssh1_challenge);
1772         ssh1_challenge = NULL;
1773         monitor_reset_key_state();
1774
1775         buffer_clear(m);
1776         buffer_put_int(m, success);
1777         mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m);
1778
1779         return (success);
1780 }
1781 #endif
1782
1783 int
1784 mm_answer_term(int sock, Buffer *req)
1785 {
1786         extern struct monitor *pmonitor;
1787         int res, status;
1788
1789         debug3("%s: tearing down sessions", __func__);
1790
1791         /* The child is terminating */
1792         session_destroy_all(&mm_session_close);
1793
1794 #ifdef USE_PAM
1795         if (options.use_pam)
1796                 sshpam_cleanup();
1797 #endif
1798
1799         while (waitpid(pmonitor->m_pid, &status, 0) == -1)
1800                 if (errno != EINTR)
1801                         exit(1);
1802
1803         res = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
1804
1805         /* Terminate process */
1806         exit(res);
1807 }
1808
1809 #ifdef SSH_AUDIT_EVENTS
1810 /* Report that an audit event occurred */
1811 int
1812 mm_answer_audit_event(int socket, Buffer *m)
1813 {
1814         ssh_audit_event_t event;
1815
1816         debug3("%s entering", __func__);
1817
1818         event = buffer_get_int(m);
1819         switch(event) {
1820         case SSH_AUTH_FAIL_PUBKEY:
1821         case SSH_AUTH_FAIL_HOSTBASED:
1822         case SSH_AUTH_FAIL_GSSAPI:
1823         case SSH_LOGIN_EXCEED_MAXTRIES:
1824         case SSH_LOGIN_ROOT_DENIED:
1825         case SSH_CONNECTION_CLOSE:
1826         case SSH_INVALID_USER:
1827                 audit_event(event);
1828                 break;
1829         default:
1830                 fatal("Audit event type %d not permitted", event);
1831         }
1832
1833         return (0);
1834 }
1835
1836 int
1837 mm_answer_audit_command(int socket, Buffer *m)
1838 {
1839         u_int len;
1840         char *cmd;
1841
1842         debug3("%s entering", __func__);
1843         cmd = buffer_get_string(m, &len);
1844         /* sanity check command, if so how? */
1845         audit_run_command(cmd);
1846         free(cmd);
1847         return (0);
1848 }
1849 #endif /* SSH_AUDIT_EVENTS */
1850
1851 void
1852 monitor_apply_keystate(struct monitor *pmonitor)
1853 {
1854         struct ssh *ssh = active_state; /* XXX */
1855         struct kex *kex;
1856         int r;
1857
1858         debug3("%s: packet_set_state", __func__);
1859         if ((r = ssh_packet_set_state(ssh, child_state)) != 0)
1860                 fatal("%s: packet_set_state: %s", __func__, ssh_err(r));
1861         sshbuf_free(child_state);
1862         child_state = NULL;
1863
1864         if ((kex = ssh->kex) != NULL) {
1865                 /* XXX set callbacks */
1866 #ifdef WITH_OPENSSL
1867                 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1868                 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1869                 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server;
1870                 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server;
1871                 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server;
1872                 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1873                 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1874 # ifdef OPENSSL_HAS_ECC
1875                 kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
1876 # endif
1877 #endif /* WITH_OPENSSL */
1878                 kex->kex[KEX_C25519_SHA256] = kexc25519_server;
1879                 kex->load_host_public_key=&get_hostkey_public_by_type;
1880                 kex->load_host_private_key=&get_hostkey_private_by_type;
1881                 kex->host_key_index=&get_hostkey_index;
1882                 kex->sign = sshd_hostkey_sign;
1883         }
1884
1885         /* Update with new address */
1886         if (options.compression) {
1887                 ssh_packet_set_compress_hooks(ssh, pmonitor->m_zlib,
1888                     (ssh_packet_comp_alloc_func *)mm_zalloc,
1889                     (ssh_packet_comp_free_func *)mm_zfree);
1890         }
1891 }
1892
1893 /* This function requries careful sanity checking */
1894
1895 void
1896 mm_get_keystate(struct monitor *pmonitor)
1897 {
1898         debug3("%s: Waiting for new keys", __func__);
1899
1900         if ((child_state = sshbuf_new()) == NULL)
1901                 fatal("%s: sshbuf_new failed", __func__);
1902         mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT,
1903             child_state);
1904         debug3("%s: GOT new keys", __func__);
1905 }
1906
1907
1908 /* XXX */
1909
1910 #define FD_CLOSEONEXEC(x) do { \
1911         if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \
1912                 fatal("fcntl(%d, F_SETFD)", x); \
1913 } while (0)
1914
1915 static void
1916 monitor_openfds(struct monitor *mon, int do_logfds)
1917 {
1918         int pair[2];
1919
1920         if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
1921                 fatal("%s: socketpair: %s", __func__, strerror(errno));
1922         FD_CLOSEONEXEC(pair[0]);
1923         FD_CLOSEONEXEC(pair[1]);
1924         mon->m_recvfd = pair[0];
1925         mon->m_sendfd = pair[1];
1926
1927         if (do_logfds) {
1928                 if (pipe(pair) == -1)
1929                         fatal("%s: pipe: %s", __func__, strerror(errno));
1930                 FD_CLOSEONEXEC(pair[0]);
1931                 FD_CLOSEONEXEC(pair[1]);
1932                 mon->m_log_recvfd = pair[0];
1933                 mon->m_log_sendfd = pair[1];
1934         } else
1935                 mon->m_log_recvfd = mon->m_log_sendfd = -1;
1936 }
1937
1938 #define MM_MEMSIZE      65536
1939
1940 struct monitor *
1941 monitor_init(void)
1942 {
1943         struct ssh *ssh = active_state;                 /* XXX */
1944         struct monitor *mon;
1945
1946         mon = xcalloc(1, sizeof(*mon));
1947
1948         monitor_openfds(mon, 1);
1949
1950         /* Used to share zlib space across processes */
1951         if (options.compression) {
1952                 mon->m_zback = mm_create(NULL, MM_MEMSIZE);
1953                 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE);
1954
1955                 /* Compression needs to share state across borders */
1956                 ssh_packet_set_compress_hooks(ssh, mon->m_zlib,
1957                     (ssh_packet_comp_alloc_func *)mm_zalloc,
1958                     (ssh_packet_comp_free_func *)mm_zfree);
1959         }
1960
1961         return mon;
1962 }
1963
1964 void
1965 monitor_reinit(struct monitor *mon)
1966 {
1967         monitor_openfds(mon, 0);
1968 }
1969
1970 #ifdef GSSAPI
1971 int
1972 mm_answer_gss_setup_ctx(int sock, Buffer *m)
1973 {
1974         gss_OID_desc goid;
1975         OM_uint32 major;
1976         u_int len;
1977
1978         goid.elements = buffer_get_string(m, &len);
1979         goid.length = len;
1980
1981         major = ssh_gssapi_server_ctx(&gsscontext, &goid);
1982
1983         free(goid.elements);
1984
1985         buffer_clear(m);
1986         buffer_put_int(m, major);
1987
1988         mm_request_send(sock, MONITOR_ANS_GSSSETUP, m);
1989
1990         /* Now we have a context, enable the step */
1991         monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1);
1992
1993         return (0);
1994 }
1995
1996 int
1997 mm_answer_gss_accept_ctx(int sock, Buffer *m)
1998 {
1999         gss_buffer_desc in;
2000         gss_buffer_desc out = GSS_C_EMPTY_BUFFER;
2001         OM_uint32 major, minor;
2002         OM_uint32 flags = 0; /* GSI needs this */
2003         u_int len;
2004
2005         in.value = buffer_get_string(m, &len);
2006         in.length = len;
2007         major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
2008         free(in.value);
2009
2010         buffer_clear(m);
2011         buffer_put_int(m, major);
2012         buffer_put_string(m, out.value, out.length);
2013         buffer_put_int(m, flags);
2014         mm_request_send(sock, MONITOR_ANS_GSSSTEP, m);
2015
2016         gss_release_buffer(&minor, &out);
2017
2018         if (major == GSS_S_COMPLETE) {
2019                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
2020                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
2021                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
2022         }
2023         return (0);
2024 }
2025
2026 int
2027 mm_answer_gss_checkmic(int sock, Buffer *m)
2028 {
2029         gss_buffer_desc gssbuf, mic;
2030         OM_uint32 ret;
2031         u_int len;
2032
2033         gssbuf.value = buffer_get_string(m, &len);
2034         gssbuf.length = len;
2035         mic.value = buffer_get_string(m, &len);
2036         mic.length = len;
2037
2038         ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic);
2039
2040         free(gssbuf.value);
2041         free(mic.value);
2042
2043         buffer_clear(m);
2044         buffer_put_int(m, ret);
2045
2046         mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m);
2047
2048         if (!GSS_ERROR(ret))
2049                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
2050
2051         return (0);
2052 }
2053
2054 int
2055 mm_answer_gss_userok(int sock, Buffer *m)
2056 {
2057         int authenticated;
2058
2059         authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
2060
2061         buffer_clear(m);
2062         buffer_put_int(m, authenticated);
2063
2064         debug3("%s: sending result %d", __func__, authenticated);
2065         mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
2066
2067         auth_method = "gssapi-with-mic";
2068
2069         /* Monitor loop will terminate if authenticated */
2070         return (authenticated);
2071 }
2072 #endif /* GSSAPI */
2073