monitor.c

   1 /* $OpenBSD: monitor.c,v 1.81 2006/07/11 20:07:25 stevesk 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 <sys/wait.h>
  33
  34 #include <errno.h>
  35 #include <fcntl.h>
  36 #ifdef HAVE_PATHS_H
  37 #include <paths.h>
  38 #endif
  39 #include <pwd.h>
  40 #include <signal.h>
  41
  42 #ifdef SKEY
  43 #include <skey.h>
  44 #endif
  45
  46 #include <openssl/dh.h>
  47
  48 #include "ssh.h"
  49 #include "auth.h"
  50 #include "kex.h"
  51 #include "dh.h"
  52 #ifdef TARGET_OS_MAC    /* XXX Broken krb5 headers on Mac */
  53 #undef TARGET_OS_MAC
  54 #include "zlib.h"
  55 #define TARGET_OS_MAC 1
  56 #else
  57 #include "zlib.h"
  58 #endif
  59 #include "packet.h"
  60 #include "auth-options.h"
  61 #include "sshpty.h"
  62 #include "channels.h"
  63 #include "session.h"
  64 #include "sshlogin.h"
  65 #include "canohost.h"
  66 #include "log.h"
  67 #include "servconf.h"
  68 #include "monitor.h"
  69 #include "monitor_mm.h"
  70 #include "monitor_wrap.h"
  71 #include "monitor_fdpass.h"
  72 #include "xmalloc.h"
  73 #include "misc.h"
  74 #include "buffer.h"
  75 #include "bufaux.h"
  76 #include "compat.h"
  77 #include "ssh2.h"
  78
  79 #ifdef GSSAPI
  80 #include "ssh-gss.h"
  81 static Gssctxt *gsscontext = NULL;
  82 #endif
  83
  84 /* Imports */
  85 extern ServerOptions options;
  86 extern u_int utmp_len;
  87 extern Newkeys *current_keys[];
  88 extern z_stream incoming_stream;
  89 extern z_stream outgoing_stream;
  90 extern u_char session_id[];
  91 extern Buffer input, output;
  92 extern Buffer auth_debug;
  93 extern int auth_debug_init;
  94 extern Buffer loginmsg;
  95
  96 /* State exported from the child */
  97
  98 struct {
  99         z_stream incoming;
 100         z_stream outgoing;
 101         u_char *keyin;
 102         u_int keyinlen;
 103         u_char *keyout;
 104         u_int keyoutlen;
 105         u_char *ivin;
 106         u_int ivinlen;
 107         u_char *ivout;
 108         u_int ivoutlen;
 109         u_char *ssh1key;
 110         u_int ssh1keylen;
 111         int ssh1cipher;
 112         int ssh1protoflags;
 113         u_char *input;
 114         u_int ilen;
 115         u_char *output;
 116         u_int olen;
 117 } child_state;
 118
 119 /* Functions on the monitor that answer unprivileged requests */
 120
 121 int mm_answer_moduli(int, Buffer *);
 122 int mm_answer_sign(int, Buffer *);
 123 int mm_answer_pwnamallow(int, Buffer *);
 124 int mm_answer_auth2_read_banner(int, Buffer *);
 125 int mm_answer_authserv(int, Buffer *);
 126 int mm_answer_authpassword(int, Buffer *);
 127 int mm_answer_bsdauthquery(int, Buffer *);
 128 int mm_answer_bsdauthrespond(int, Buffer *);
 129 int mm_answer_skeyquery(int, Buffer *);
 130 int mm_answer_skeyrespond(int, Buffer *);
 131 int mm_answer_keyallowed(int, Buffer *);
 132 int mm_answer_keyverify(int, Buffer *);
 133 int mm_answer_pty(int, Buffer *);
 134 int mm_answer_pty_cleanup(int, Buffer *);
 135 int mm_answer_term(int, Buffer *);
 136 int mm_answer_rsa_keyallowed(int, Buffer *);
 137 int mm_answer_rsa_challenge(int, Buffer *);
 138 int mm_answer_rsa_response(int, Buffer *);
 139 int mm_answer_sesskey(int, Buffer *);
 140 int mm_answer_sessid(int, Buffer *);
 141
 142 #ifdef USE_PAM
 143 int mm_answer_pam_start(int, Buffer *);
 144 int mm_answer_pam_account(int, Buffer *);
 145 int mm_answer_pam_init_ctx(int, Buffer *);
 146 int mm_answer_pam_query(int, Buffer *);
 147 int mm_answer_pam_respond(int, Buffer *);
 148 int mm_answer_pam_free_ctx(int, Buffer *);
 149 #endif
 150
 151 #ifdef GSSAPI
 152 int mm_answer_gss_setup_ctx(int, Buffer *);
 153 int mm_answer_gss_accept_ctx(int, Buffer *);
 154 int mm_answer_gss_userok(int, Buffer *);
 155 int mm_answer_gss_checkmic(int, Buffer *);
 156 #endif
 157
 158 #ifdef SSH_AUDIT_EVENTS
 159 int mm_answer_audit_event(int, Buffer *);
 160 int mm_answer_audit_command(int, Buffer *);
 161 #endif
 162
 163 static Authctxt *authctxt;
 164 static BIGNUM *ssh1_challenge = NULL;   /* used for ssh1 rsa auth */
 165
 166 /* local state for key verify */
 167 static u_char *key_blob = NULL;
 168 static u_int key_bloblen = 0;
 169 static int key_blobtype = MM_NOKEY;
 170 static char *hostbased_cuser = NULL;
 171 static char *hostbased_chost = NULL;
 172 static char *auth_method = "unknown";
 173 static u_int session_id2_len = 0;
 174 static u_char *session_id2 = NULL;
 175 static pid_t monitor_child_pid;
 176
 177 struct mon_table {
 178         enum monitor_reqtype type;
 179         int flags;
 180         int (*f)(int, Buffer *);
 181 };
 182
 183 #define MON_ISAUTH      0x0004  /* Required for Authentication */
 184 #define MON_AUTHDECIDE  0x0008  /* Decides Authentication */
 185 #define MON_ONCE        0x0010  /* Disable after calling */
 186 #define MON_ALOG        0x0020  /* Log auth attempt without authenticating */
 187
 188 #define MON_AUTH        (MON_ISAUTH|MON_AUTHDECIDE)
 189
 190 #define MON_PERMIT      0x1000  /* Request is permitted */
 191
 192 struct mon_table mon_dispatch_proto20[] = {
 193     {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli},
 194     {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
 195     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
 196     {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
 197     {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
 198     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 199 #ifdef USE_PAM
 200     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
 201     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
 202     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
 203     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
 204     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
 205     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 206 #endif
 207 #ifdef SSH_AUDIT_EVENTS
 208     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 209 #endif
 210 #ifdef BSD_AUTH
 211     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
 212     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
 213 #endif
 214 #ifdef SKEY
 215     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
 216     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
 217 #endif
 218     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
 219     {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
 220 #ifdef GSSAPI
 221     {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx},
 222     {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx},
 223     {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok},
 224     {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic},
 225 #endif
 226     {0, 0, NULL}
 227 };
 228
 229 struct mon_table mon_dispatch_postauth20[] = {
 230     {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
 231     {MONITOR_REQ_SIGN, 0, mm_answer_sign},
 232     {MONITOR_REQ_PTY, 0, mm_answer_pty},
 233     {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
 234     {MONITOR_REQ_TERM, 0, mm_answer_term},
 235 #ifdef SSH_AUDIT_EVENTS
 236     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 237     {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
 238 #endif
 239     {0, 0, NULL}
 240 };
 241
 242 struct mon_table mon_dispatch_proto15[] = {
 243     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
 244     {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey},
 245     {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid},
 246     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 247     {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_rsa_keyallowed},
 248     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_keyallowed},
 249     {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge},
 250     {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response},
 251 #ifdef BSD_AUTH
 252     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
 253     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
 254 #endif
 255 #ifdef SKEY
 256     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
 257     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
 258 #endif
 259 #ifdef USE_PAM
 260     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
 261     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
 262     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
 263     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
 264     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
 265     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 266 #endif
 267 #ifdef SSH_AUDIT_EVENTS
 268     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 269 #endif
 270     {0, 0, NULL}
 271 };
 272
 273 struct mon_table mon_dispatch_postauth15[] = {
 274     {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty},
 275     {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup},
 276     {MONITOR_REQ_TERM, 0, mm_answer_term},
 277 #ifdef SSH_AUDIT_EVENTS
 278     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 279     {MONITOR_REQ_AUDIT_COMMAND, MON_ONCE, mm_answer_audit_command},
 280 #endif
 281     {0, 0, NULL}
 282 };
 283
 284 struct mon_table *mon_dispatch;
 285
 286 /* Specifies if a certain message is allowed at the moment */
 287
 288 static void
 289 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit)
 290 {
 291         while (ent->f != NULL) {
 292                 if (ent->type == type) {
 293                         ent->flags &= ~MON_PERMIT;
 294                         ent->flags |= permit ? MON_PERMIT : 0;
 295                         return;
 296                 }
 297                 ent++;
 298         }
 299 }
 300
 301 static void
 302 monitor_permit_authentications(int permit)
 303 {
 304         struct mon_table *ent = mon_dispatch;
 305
 306         while (ent->f != NULL) {
 307                 if (ent->flags & MON_AUTH) {
 308                         ent->flags &= ~MON_PERMIT;
 309                         ent->flags |= permit ? MON_PERMIT : 0;
 310                 }
 311                 ent++;
 312         }
 313 }
 314
 315 void
 316 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
 317 {
 318         struct mon_table *ent;
 319         int authenticated = 0;
 320
 321         debug3("preauth child monitor started");
 322
 323         authctxt = _authctxt;
 324         memset(authctxt, 0, sizeof(*authctxt));
 325
 326         authctxt->loginmsg = &loginmsg;
 327
 328         if (compat20) {
 329                 mon_dispatch = mon_dispatch_proto20;
 330
 331                 /* Permit requests for moduli and signatures */
 332                 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 333                 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 334         } else {
 335                 mon_dispatch = mon_dispatch_proto15;
 336
 337                 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1);
 338         }
 339
 340         /* The first few requests do not require asynchronous access */
 341         while (!authenticated) {
 342                 auth_method = "unknown";
 343                 authenticated = monitor_read(pmonitor, mon_dispatch, &ent);
 344                 if (authenticated) {
 345                         if (!(ent->flags & MON_AUTHDECIDE))
 346                                 fatal("%s: unexpected authentication from %d",
 347                                     __func__, ent->type);
 348                         if (authctxt->pw->pw_uid == 0 &&
 349                             !auth_root_allowed(auth_method))
 350                                 authenticated = 0;
 351 #ifdef USE_PAM
 352                         /* PAM needs to perform account checks after auth */
 353                         if (options.use_pam && authenticated) {
 354                                 Buffer m;
 355
 356                                 buffer_init(&m);
 357                                 mm_request_receive_expect(pmonitor->m_sendfd,
 358                                     MONITOR_REQ_PAM_ACCOUNT, &m);
 359                                 authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m);
 360                                 buffer_free(&m);
 361                         }
 362 #endif
 363                 }
 364
 365                 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
 366                         auth_log(authctxt, authenticated, auth_method,
 367                             compat20 ? " ssh2" : "");
 368                         if (!authenticated)
 369                                 authctxt->failures++;
 370                 }
 371         }
 372
 373         if (!authctxt->valid)
 374                 fatal("%s: authenticated invalid user", __func__);
 375         if (strcmp(auth_method, "unknown") == 0)
 376                 fatal("%s: authentication method name unknown", __func__);
 377
 378         debug("%s: %s has been authenticated by privileged process",
 379             __func__, authctxt->user);
 380
 381         mm_get_keystate(pmonitor);
 382 }
 383
 384 static void
 385 monitor_set_child_handler(pid_t pid)
 386 {
 387         monitor_child_pid = pid;
 388 }
 389
 390 static void
 391 monitor_child_handler(int sig)
 392 {
 393         kill(monitor_child_pid, sig);
 394 }
 395
 396 void
 397 monitor_child_postauth(struct monitor *pmonitor)
 398 {
 399         monitor_set_child_handler(pmonitor->m_pid);
 400         signal(SIGHUP, &monitor_child_handler);
 401         signal(SIGTERM, &monitor_child_handler);
 402
 403         if (compat20) {
 404                 mon_dispatch = mon_dispatch_postauth20;
 405
 406                 /* Permit requests for moduli and signatures */
 407                 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 408                 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 409                 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
 410         } else {
 411                 mon_dispatch = mon_dispatch_postauth15;
 412                 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
 413         }
 414         if (!no_pty_flag) {
 415                 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
 416                 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1);
 417         }
 418
 419         for (;;)
 420                 monitor_read(pmonitor, mon_dispatch, NULL);
 421 }
 422
 423 void
 424 monitor_sync(struct monitor *pmonitor)
 425 {
 426         if (options.compression) {
 427                 /* The member allocation is not visible, so sync it */
 428                 mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback);
 429         }
 430 }
 431
 432 int
 433 monitor_read(struct monitor *pmonitor, struct mon_table *ent,
 434     struct mon_table **pent)
 435 {
 436         Buffer m;
 437         int ret;
 438         u_char type;
 439
 440         buffer_init(&m);
 441
 442         mm_request_receive(pmonitor->m_sendfd, &m);
 443         type = buffer_get_char(&m);
 444
 445         debug3("%s: checking request %d", __func__, type);
 446
 447         while (ent->f != NULL) {
 448                 if (ent->type == type)
 449                         break;
 450                 ent++;
 451         }
 452
 453         if (ent->f != NULL) {
 454                 if (!(ent->flags & MON_PERMIT))
 455                         fatal("%s: unpermitted request %d", __func__,
 456                             type);
 457                 ret = (*ent->f)(pmonitor->m_sendfd, &m);
 458                 buffer_free(&m);
 459
 460                 /* The child may use this request only once, disable it */
 461                 if (ent->flags & MON_ONCE) {
 462                         debug2("%s: %d used once, disabling now", __func__,
 463                             type);
 464                         ent->flags &= ~MON_PERMIT;
 465                 }
 466
 467                 if (pent != NULL)
 468                         *pent = ent;
 469
 470                 return ret;
 471         }
 472
 473         fatal("%s: unsupported request: %d", __func__, type);
 474
 475         /* NOTREACHED */
 476         return (-1);
 477 }
 478
 479 /* allowed key state */
 480 static int
 481 monitor_allowed_key(u_char *blob, u_int bloblen)
 482 {
 483         /* make sure key is allowed */
 484         if (key_blob == NULL || key_bloblen != bloblen ||
 485             memcmp(key_blob, blob, key_bloblen))
 486                 return (0);
 487         return (1);
 488 }
 489
 490 static void
 491 monitor_reset_key_state(void)
 492 {
 493         /* reset state */
 494         if (key_blob != NULL)
 495                 xfree(key_blob);
 496         if (hostbased_cuser != NULL)
 497                 xfree(hostbased_cuser);
 498         if (hostbased_chost != NULL)
 499                 xfree(hostbased_chost);
 500         key_blob = NULL;
 501         key_bloblen = 0;
 502         key_blobtype = MM_NOKEY;
 503         hostbased_cuser = NULL;
 504         hostbased_chost = NULL;
 505 }
 506
 507 int
 508 mm_answer_moduli(int sock, Buffer *m)
 509 {
 510         DH *dh;
 511         int min, want, max;
 512
 513         min = buffer_get_int(m);
 514         want = buffer_get_int(m);
 515         max = buffer_get_int(m);
 516
 517         debug3("%s: got parameters: %d %d %d",
 518             __func__, min, want, max);
 519         /* We need to check here, too, in case the child got corrupted */
 520         if (max < min || want < min || max < want)
 521                 fatal("%s: bad parameters: %d %d %d",
 522                     __func__, min, want, max);
 523
 524         buffer_clear(m);
 525
 526         dh = choose_dh(min, want, max);
 527         if (dh == NULL) {
 528                 buffer_put_char(m, 0);
 529                 return (0);
 530         } else {
 531                 /* Send first bignum */
 532                 buffer_put_char(m, 1);
 533                 buffer_put_bignum2(m, dh->p);
 534                 buffer_put_bignum2(m, dh->g);
 535
 536                 DH_free(dh);
 537         }
 538         mm_request_send(sock, MONITOR_ANS_MODULI, m);
 539         return (0);
 540 }
 541
 542 int
 543 mm_answer_sign(int sock, Buffer *m)
 544 {
 545         Key *key;
 546         u_char *p;
 547         u_char *signature;
 548         u_int siglen, datlen;
 549         int keyid;
 550
 551         debug3("%s", __func__);
 552
 553         keyid = buffer_get_int(m);
 554         p = buffer_get_string(m, &datlen);
 555
 556         /*
 557          * Supported KEX types will only return SHA1 (20 byte) or
 558          * SHA256 (32 byte) hashes
 559          */
 560         if (datlen != 20 && datlen != 32)
 561                 fatal("%s: data length incorrect: %u", __func__, datlen);
 562
 563         /* save session id, it will be passed on the first call */
 564         if (session_id2_len == 0) {
 565                 session_id2_len = datlen;
 566                 session_id2 = xmalloc(session_id2_len);
 567                 memcpy(session_id2, p, session_id2_len);
 568         }
 569
 570         if ((key = get_hostkey_by_index(keyid)) == NULL)
 571                 fatal("%s: no hostkey from index %d", __func__, keyid);
 572         if (key_sign(key, &signature, &siglen, p, datlen) < 0)
 573                 fatal("%s: key_sign failed", __func__);
 574
 575         debug3("%s: signature %p(%u)", __func__, signature, siglen);
 576
 577         buffer_clear(m);
 578         buffer_put_string(m, signature, siglen);
 579
 580         xfree(p);
 581         xfree(signature);
 582
 583         mm_request_send(sock, MONITOR_ANS_SIGN, m);
 584
 585         /* Turn on permissions for getpwnam */
 586         monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
 587
 588         return (0);
 589 }
 590
 591 /* Retrieves the password entry and also checks if the user is permitted */
 592
 593 int
 594 mm_answer_pwnamallow(int sock, Buffer *m)
 595 {
 596         char *username;
 597         struct passwd *pwent;
 598         int allowed = 0;
 599
 600         debug3("%s", __func__);
 601
 602         if (authctxt->attempt++ != 0)
 603                 fatal("%s: multiple attempts for getpwnam", __func__);
 604
 605         username = buffer_get_string(m, NULL);
 606
 607         pwent = getpwnamallow(username);
 608
 609         authctxt->user = xstrdup(username);
 610         setproctitle("%s [priv]", pwent ? username : "unknown");
 611         xfree(username);
 612
 613         buffer_clear(m);
 614
 615         if (pwent == NULL) {
 616                 buffer_put_char(m, 0);
 617                 authctxt->pw = fakepw();
 618                 goto out;
 619         }
 620
 621         allowed = 1;
 622         authctxt->pw = pwent;
 623         authctxt->valid = 1;
 624
 625         buffer_put_char(m, 1);
 626         buffer_put_string(m, pwent, sizeof(struct passwd));
 627         buffer_put_cstring(m, pwent->pw_name);
 628         buffer_put_cstring(m, "*");
 629         buffer_put_cstring(m, pwent->pw_gecos);
 630 #ifdef HAVE_PW_CLASS_IN_PASSWD
 631         buffer_put_cstring(m, pwent->pw_class);
 632 #endif
 633         buffer_put_cstring(m, pwent->pw_dir);
 634         buffer_put_cstring(m, pwent->pw_shell);
 635
 636  out:
 637         debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed);
 638         mm_request_send(sock, MONITOR_ANS_PWNAM, m);
 639
 640         /* For SSHv1 allow authentication now */
 641         if (!compat20)
 642                 monitor_permit_authentications(1);
 643         else {
 644                 /* Allow service/style information on the auth context */
 645                 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
 646                 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
 647         }
 648
 649 #ifdef USE_PAM
 650         if (options.use_pam)
 651                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
 652 #endif
 653 #ifdef SSH_AUDIT_EVENTS
 654         monitor_permit(mon_dispatch, MONITOR_REQ_AUDIT_COMMAND, 1);
 655 #endif
 656
 657         return (0);
 658 }
 659
 660 int mm_answer_auth2_read_banner(int sock, Buffer *m)
 661 {
 662         char *banner;
 663
 664         buffer_clear(m);
 665         banner = auth2_read_banner();
 666         buffer_put_cstring(m, banner != NULL ? banner : "");
 667         mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m);
 668
 669         if (banner != NULL)
 670                 xfree(banner);
 671
 672         return (0);
 673 }
 674
 675 int
 676 mm_answer_authserv(int sock, Buffer *m)
 677 {
 678         monitor_permit_authentications(1);
 679
 680         authctxt->service = buffer_get_string(m, NULL);
 681         authctxt->style = buffer_get_string(m, NULL);
 682         debug3("%s: service=%s, style=%s",
 683             __func__, authctxt->service, authctxt->style);
 684
 685         if (strlen(authctxt->style) == 0) {
 686                 xfree(authctxt->style);
 687                 authctxt->style = NULL;
 688         }
 689
 690         return (0);
 691 }
 692
 693 int
 694 mm_answer_authpassword(int sock, Buffer *m)
 695 {
 696         static int call_count;
 697         char *passwd;
 698         int authenticated;
 699         u_int plen;
 700
 701         passwd = buffer_get_string(m, &plen);
 702         /* Only authenticate if the context is valid */
 703         authenticated = options.password_authentication &&
 704             auth_password(authctxt, passwd);
 705         memset(passwd, 0, strlen(passwd));
 706         xfree(passwd);
 707
 708         buffer_clear(m);
 709         buffer_put_int(m, authenticated);
 710
 711         debug3("%s: sending result %d", __func__, authenticated);
 712         mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m);
 713
 714         call_count++;
 715         if (plen == 0 && call_count == 1)
 716                 auth_method = "none";
 717         else
 718                 auth_method = "password";
 719
 720         /* Causes monitor loop to terminate if authenticated */
 721         return (authenticated);
 722 }
 723
 724 #ifdef BSD_AUTH
 725 int
 726 mm_answer_bsdauthquery(int sock, Buffer *m)
 727 {
 728         char *name, *infotxt;
 729         u_int numprompts;
 730         u_int *echo_on;
 731         char **prompts;
 732         u_int success;
 733
 734         success = bsdauth_query(authctxt, &name, &infotxt, &numprompts,
 735             &prompts, &echo_on) < 0 ? 0 : 1;
 736
 737         buffer_clear(m);
 738         buffer_put_int(m, success);
 739         if (success)
 740                 buffer_put_cstring(m, prompts[0]);
 741
 742         debug3("%s: sending challenge success: %u", __func__, success);
 743         mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m);
 744
 745         if (success) {
 746                 xfree(name);
 747                 xfree(infotxt);
 748                 xfree(prompts);
 749                 xfree(echo_on);
 750         }
 751
 752         return (0);
 753 }
 754
 755 int
 756 mm_answer_bsdauthrespond(int sock, Buffer *m)
 757 {
 758         char *response;
 759         int authok;
 760
 761         if (authctxt->as == 0)
 762                 fatal("%s: no bsd auth session", __func__);
 763
 764         response = buffer_get_string(m, NULL);
 765         authok = options.challenge_response_authentication &&
 766             auth_userresponse(authctxt->as, response, 0);
 767         authctxt->as = NULL;
 768         debug3("%s: <%s> = <%d>", __func__, response, authok);
 769         xfree(response);
 770
 771         buffer_clear(m);
 772         buffer_put_int(m, authok);
 773
 774         debug3("%s: sending authenticated: %d", __func__, authok);
 775         mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
 776
 777         auth_method = "bsdauth";
 778
 779         return (authok != 0);
 780 }
 781 #endif
 782
 783 #ifdef SKEY
 784 int
 785 mm_answer_skeyquery(int sock, Buffer *m)
 786 {
 787         struct skey skey;
 788         char challenge[1024];
 789         u_int success;
 790
 791         success = _compat_skeychallenge(&skey, authctxt->user, challenge,
 792             sizeof(challenge)) < 0 ? 0 : 1;
 793
 794         buffer_clear(m);
 795         buffer_put_int(m, success);
 796         if (success)
 797                 buffer_put_cstring(m, challenge);
 798
 799         debug3("%s: sending challenge success: %u", __func__, success);
 800         mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m);
 801
 802         return (0);
 803 }
 804
 805 int
 806 mm_answer_skeyrespond(int sock, Buffer *m)
 807 {
 808         char *response;
 809         int authok;
 810
 811         response = buffer_get_string(m, NULL);
 812
 813         authok = (options.challenge_response_authentication &&
 814             authctxt->valid &&
 815             skey_haskey(authctxt->pw->pw_name) == 0 &&
 816             skey_passcheck(authctxt->pw->pw_name, response) != -1);
 817
 818         xfree(response);
 819
 820         buffer_clear(m);
 821         buffer_put_int(m, authok);
 822
 823         debug3("%s: sending authenticated: %d", __func__, authok);
 824         mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m);
 825
 826         auth_method = "skey";
 827
 828         return (authok != 0);
 829 }
 830 #endif
 831
 832 #ifdef USE_PAM
 833 int
 834 mm_answer_pam_start(int sock, Buffer *m)
 835 {
 836         if (!options.use_pam)
 837                 fatal("UsePAM not set, but ended up in %s anyway", __func__);
 838
 839         start_pam(authctxt);
 840
 841         monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1);
 842
 843         return (0);
 844 }
 845
 846 int
 847 mm_answer_pam_account(int sock, Buffer *m)
 848 {
 849         u_int ret;
 850
 851         if (!options.use_pam)
 852                 fatal("UsePAM not set, but ended up in %s anyway", __func__);
 853
 854         ret = do_pam_account();
 855
 856         buffer_put_int(m, ret);
 857         buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
 858
 859         mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m);
 860
 861         return (ret);
 862 }
 863
 864 static void *sshpam_ctxt, *sshpam_authok;
 865 extern KbdintDevice sshpam_device;
 866
 867 int
 868 mm_answer_pam_init_ctx(int sock, Buffer *m)
 869 {
 870
 871         debug3("%s", __func__);
 872         authctxt->user = buffer_get_string(m, NULL);
 873         sshpam_ctxt = (sshpam_device.init_ctx)(authctxt);
 874         sshpam_authok = NULL;
 875         buffer_clear(m);
 876         if (sshpam_ctxt != NULL) {
 877                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
 878                 buffer_put_int(m, 1);
 879         } else {
 880                 buffer_put_int(m, 0);
 881         }
 882         mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m);
 883         return (0);
 884 }
 885
 886 int
 887 mm_answer_pam_query(int sock, Buffer *m)
 888 {
 889         char *name, *info, **prompts;
 890         u_int i, num, *echo_on;
 891         int ret;
 892
 893         debug3("%s", __func__);
 894         sshpam_authok = NULL;
 895         ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, &num, &prompts, &echo_on);
 896         if (ret == 0 && num == 0)
 897                 sshpam_authok = sshpam_ctxt;
 898         if (num > 1 || name == NULL || info == NULL)
 899                 ret = -1;
 900         buffer_clear(m);
 901         buffer_put_int(m, ret);
 902         buffer_put_cstring(m, name);
 903         xfree(name);
 904         buffer_put_cstring(m, info);
 905         xfree(info);
 906         buffer_put_int(m, num);
 907         for (i = 0; i < num; ++i) {
 908                 buffer_put_cstring(m, prompts[i]);
 909                 xfree(prompts[i]);
 910                 buffer_put_int(m, echo_on[i]);
 911         }
 912         if (prompts != NULL)
 913                 xfree(prompts);
 914         if (echo_on != NULL)
 915                 xfree(echo_on);
 916         auth_method = "keyboard-interactive/pam";
 917         mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m);
 918         return (0);
 919 }
 920
 921 int
 922 mm_answer_pam_respond(int sock, Buffer *m)
 923 {
 924         char **resp;
 925         u_int i, num;
 926         int ret;
 927
 928         debug3("%s", __func__);
 929         sshpam_authok = NULL;
 930         num = buffer_get_int(m);
 931         if (num > 0) {
 932                 resp = xcalloc(num, sizeof(char *));
 933                 for (i = 0; i < num; ++i)
 934                         resp[i] = buffer_get_string(m, NULL);
 935                 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp);
 936                 for (i = 0; i < num; ++i)
 937                         xfree(resp[i]);
 938                 xfree(resp);
 939         } else {
 940                 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL);
 941         }
 942         buffer_clear(m);
 943         buffer_put_int(m, ret);
 944         mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m);
 945         auth_method = "keyboard-interactive/pam";
 946         if (ret == 0)
 947                 sshpam_authok = sshpam_ctxt;
 948         return (0);
 949 }
 950
 951 int
 952 mm_answer_pam_free_ctx(int sock, Buffer *m)
 953 {
 954
 955         debug3("%s", __func__);
 956         (sshpam_device.free_ctx)(sshpam_ctxt);
 957         buffer_clear(m);
 958         mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m);
 959         auth_method = "keyboard-interactive/pam";
 960         return (sshpam_authok == sshpam_ctxt);
 961 }
 962 #endif
 963
 964 static void
 965 mm_append_debug(Buffer *m)
 966 {
 967         if (auth_debug_init && buffer_len(&auth_debug)) {
 968                 debug3("%s: Appending debug messages for child", __func__);
 969                 buffer_append(m, buffer_ptr(&auth_debug),
 970                     buffer_len(&auth_debug));
 971                 buffer_clear(&auth_debug);
 972         }
 973 }
 974
 975 int
 976 mm_answer_keyallowed(int sock, Buffer *m)
 977 {
 978         Key *key;
 979         char *cuser, *chost;
 980         u_char *blob;
 981         u_int bloblen;
 982         enum mm_keytype type = 0;
 983         int allowed = 0;
 984
 985         debug3("%s entering", __func__);
 986
 987         type = buffer_get_int(m);
 988         cuser = buffer_get_string(m, NULL);
 989         chost = buffer_get_string(m, NULL);
 990         blob = buffer_get_string(m, &bloblen);
 991
 992         key = key_from_blob(blob, bloblen);
 993
 994         if ((compat20 && type == MM_RSAHOSTKEY) ||
 995             (!compat20 && type != MM_RSAHOSTKEY))
 996                 fatal("%s: key type and protocol mismatch", __func__);
 997
 998         debug3("%s: key_from_blob: %p", __func__, key);
 999
1000         if (key != NULL && authctxt->valid) {
1001                 switch (type) {
1002                 case MM_USERKEY:
1003                         allowed = options.pubkey_authentication &&
1004                             user_key_allowed(authctxt->pw, key);
1005                         auth_method = "publickey";
1006                         break;
1007                 case MM_HOSTKEY:
1008                         allowed = options.hostbased_authentication &&
1009                             hostbased_key_allowed(authctxt->pw,
1010                             cuser, chost, key);
1011                         auth_method = "hostbased";
1012                         break;
1013                 case MM_RSAHOSTKEY:
1014                         key->type = KEY_RSA1; /* XXX */
1015                         allowed = options.rhosts_rsa_authentication &&
1016                             auth_rhosts_rsa_key_allowed(authctxt->pw,
1017                             cuser, chost, key);
1018                         auth_method = "rsa";
1019                         break;
1020                 default:
1021                         fatal("%s: unknown key type %d", __func__, type);
1022                         break;
1023                 }
1024         }
1025         if (key != NULL)
1026                 key_free(key);
1027
1028         /* clear temporarily storage (used by verify) */
1029         monitor_reset_key_state();
1030
1031         if (allowed) {
1032                 /* Save temporarily for comparison in verify */
1033                 key_blob = blob;
1034                 key_bloblen = bloblen;
1035                 key_blobtype = type;
1036                 hostbased_cuser = cuser;
1037                 hostbased_chost = chost;
1038         } else {
1039                 /* Log failed attempt */
1040                 auth_log(authctxt, 0, auth_method, compat20 ? " ssh2" : "");
1041                 xfree(blob);
1042                 xfree(cuser);
1043                 xfree(chost);
1044         }
1045
1046         debug3("%s: key %p is %s",
1047             __func__, key, allowed ? "allowed" : "disallowed");
1048
1049         buffer_clear(m);
1050         buffer_put_int(m, allowed);
1051         buffer_put_int(m, forced_command != NULL);
1052
1053         mm_append_debug(m);
1054
1055         mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m);
1056
1057         if (type == MM_RSAHOSTKEY)
1058                 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1059
1060         return (0);
1061 }
1062
1063 static int
1064 monitor_valid_userblob(u_char *data, u_int datalen)
1065 {
1066         Buffer b;
1067         char *p;
1068         u_int len;
1069         int fail = 0;
1070
1071         buffer_init(&b);
1072         buffer_append(&b, data, datalen);
1073
1074         if (datafellows & SSH_OLD_SESSIONID) {
1075                 p = buffer_ptr(&b);
1076                 len = buffer_len(&b);
1077                 if ((session_id2 == NULL) ||
1078                     (len < session_id2_len) ||
1079                     (memcmp(p, session_id2, session_id2_len) != 0))
1080                         fail++;
1081                 buffer_consume(&b, session_id2_len);
1082         } else {
1083                 p = buffer_get_string(&b, &len);
1084                 if ((session_id2 == NULL) ||
1085                     (len != session_id2_len) ||
1086                     (memcmp(p, session_id2, session_id2_len) != 0))
1087                         fail++;
1088                 xfree(p);
1089         }
1090         if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1091                 fail++;
1092         p = buffer_get_string(&b, NULL);
1093         if (strcmp(authctxt->user, p) != 0) {
1094                 logit("wrong user name passed to monitor: expected %s != %.100s",
1095                     authctxt->user, p);
1096                 fail++;
1097         }
1098         xfree(p);
1099         buffer_skip_string(&b);
1100         if (datafellows & SSH_BUG_PKAUTH) {
1101                 if (!buffer_get_char(&b))
1102                         fail++;
1103         } else {
1104                 p = buffer_get_string(&b, NULL);
1105                 if (strcmp("publickey", p) != 0)
1106                         fail++;
1107                 xfree(p);
1108                 if (!buffer_get_char(&b))
1109                         fail++;
1110                 buffer_skip_string(&b);
1111         }
1112         buffer_skip_string(&b);
1113         if (buffer_len(&b) != 0)
1114                 fail++;
1115         buffer_free(&b);
1116         return (fail == 0);
1117 }
1118
1119 static int
1120 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser,
1121     char *chost)
1122 {
1123         Buffer b;
1124         char *p;
1125         u_int len;
1126         int fail = 0;
1127
1128         buffer_init(&b);
1129         buffer_append(&b, data, datalen);
1130
1131         p = buffer_get_string(&b, &len);
1132         if ((session_id2 == NULL) ||
1133             (len != session_id2_len) ||
1134             (memcmp(p, session_id2, session_id2_len) != 0))
1135                 fail++;
1136         xfree(p);
1137
1138         if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1139                 fail++;
1140         p = buffer_get_string(&b, NULL);
1141         if (strcmp(authctxt->user, p) != 0) {
1142                 logit("wrong user name passed to monitor: expected %s != %.100s",
1143                     authctxt->user, p);
1144                 fail++;
1145         }
1146         xfree(p);
1147         buffer_skip_string(&b); /* service */
1148         p = buffer_get_string(&b, NULL);
1149         if (strcmp(p, "hostbased") != 0)
1150                 fail++;
1151         xfree(p);
1152         buffer_skip_string(&b); /* pkalg */
1153         buffer_skip_string(&b); /* pkblob */
1154
1155         /* verify client host, strip trailing dot if necessary */
1156         p = buffer_get_string(&b, NULL);
1157         if (((len = strlen(p)) > 0) && p[len - 1] == '.')
1158                 p[len - 1] = '\0';
1159         if (strcmp(p, chost) != 0)
1160                 fail++;
1161         xfree(p);
1162
1163         /* verify client user */
1164         p = buffer_get_string(&b, NULL);
1165         if (strcmp(p, cuser) != 0)
1166                 fail++;
1167         xfree(p);
1168
1169         if (buffer_len(&b) != 0)
1170                 fail++;
1171         buffer_free(&b);
1172         return (fail == 0);
1173 }
1174
1175 int
1176 mm_answer_keyverify(int sock, Buffer *m)
1177 {
1178         Key *key;
1179         u_char *signature, *data, *blob;
1180         u_int signaturelen, datalen, bloblen;
1181         int verified = 0;
1182         int valid_data = 0;
1183
1184         blob = buffer_get_string(m, &bloblen);
1185         signature = buffer_get_string(m, &signaturelen);
1186         data = buffer_get_string(m, &datalen);
1187
1188         if (hostbased_cuser == NULL || hostbased_chost == NULL ||
1189           !monitor_allowed_key(blob, bloblen))
1190                 fatal("%s: bad key, not previously allowed", __func__);
1191
1192         key = key_from_blob(blob, bloblen);
1193         if (key == NULL)
1194                 fatal("%s: bad public key blob", __func__);
1195
1196         switch (key_blobtype) {
1197         case MM_USERKEY:
1198                 valid_data = monitor_valid_userblob(data, datalen);
1199                 break;
1200         case MM_HOSTKEY:
1201                 valid_data = monitor_valid_hostbasedblob(data, datalen,
1202                     hostbased_cuser, hostbased_chost);
1203                 break;
1204         default:
1205                 valid_data = 0;
1206                 break;
1207         }
1208         if (!valid_data)
1209                 fatal("%s: bad signature data blob", __func__);
1210
1211         verified = key_verify(key, signature, signaturelen, data, datalen);
1212         debug3("%s: key %p signature %s",
1213             __func__, key, verified ? "verified" : "unverified");
1214
1215         key_free(key);
1216         xfree(blob);
1217         xfree(signature);
1218         xfree(data);
1219
1220         auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased";
1221
1222         monitor_reset_key_state();
1223
1224         buffer_clear(m);
1225         buffer_put_int(m, verified);
1226         mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m);
1227
1228         return (verified);
1229 }
1230
1231 static void
1232 mm_record_login(Session *s, struct passwd *pw)
1233 {
1234         socklen_t fromlen;
1235         struct sockaddr_storage from;
1236
1237         /*
1238          * Get IP address of client. If the connection is not a socket, let
1239          * the address be 0.0.0.0.
1240          */
1241         memset(&from, 0, sizeof(from));
1242         fromlen = sizeof(from);
1243         if (packet_connection_is_on_socket()) {
1244                 if (getpeername(packet_get_connection_in(),
1245                     (struct sockaddr *)&from, &fromlen) < 0) {
1246                         debug("getpeername: %.100s", strerror(errno));
1247                         cleanup_exit(255);
1248                 }
1249         }
1250         /* Record that there was a login on that tty from the remote host. */
1251         record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
1252             get_remote_name_or_ip(utmp_len, options.use_dns),
1253             (struct sockaddr *)&from, fromlen);
1254 }
1255
1256 static void
1257 mm_session_close(Session *s)
1258 {
1259         debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid);
1260         if (s->ttyfd != -1) {
1261                 debug3("%s: tty %s ptyfd %d",  __func__, s->tty, s->ptyfd);
1262                 session_pty_cleanup2(s);
1263         }
1264         s->used = 0;
1265 }
1266
1267 int
1268 mm_answer_pty(int sock, Buffer *m)
1269 {
1270         extern struct monitor *pmonitor;
1271         Session *s;
1272         int res, fd0;
1273
1274         debug3("%s entering", __func__);
1275
1276         buffer_clear(m);
1277         s = session_new();
1278         if (s == NULL)
1279                 goto error;
1280         s->authctxt = authctxt;
1281         s->pw = authctxt->pw;
1282         s->pid = pmonitor->m_pid;
1283         res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
1284         if (res == 0)
1285                 goto error;
1286         pty_setowner(authctxt->pw, s->tty);
1287
1288         buffer_put_int(m, 1);
1289         buffer_put_cstring(m, s->tty);
1290
1291         /* We need to trick ttyslot */
1292         if (dup2(s->ttyfd, 0) == -1)
1293                 fatal("%s: dup2", __func__);
1294
1295         mm_record_login(s, authctxt->pw);
1296
1297         /* Now we can close the file descriptor again */
1298         close(0);
1299
1300         /* send messages generated by record_login */
1301         buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
1302         buffer_clear(&loginmsg);
1303
1304         mm_request_send(sock, MONITOR_ANS_PTY, m);
1305
1306         mm_send_fd(sock, s->ptyfd);
1307         mm_send_fd(sock, s->ttyfd);
1308
1309         /* make sure nothing uses fd 0 */
1310         if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0)
1311                 fatal("%s: open(/dev/null): %s", __func__, strerror(errno));
1312         if (fd0 != 0)
1313                 error("%s: fd0 %d != 0", __func__, fd0);
1314
1315         /* slave is not needed */
1316         close(s->ttyfd);
1317         s->ttyfd = s->ptyfd;
1318         /* no need to dup() because nobody closes ptyfd */
1319         s->ptymaster = s->ptyfd;
1320
1321         debug3("%s: tty %s ptyfd %d",  __func__, s->tty, s->ttyfd);
1322
1323         return (0);
1324
1325  error:
1326         if (s != NULL)
1327                 mm_session_close(s);
1328         buffer_put_int(m, 0);
1329         mm_request_send(sock, MONITOR_ANS_PTY, m);
1330         return (0);
1331 }
1332
1333 int
1334 mm_answer_pty_cleanup(int sock, Buffer *m)
1335 {
1336         Session *s;
1337         char *tty;
1338
1339         debug3("%s entering", __func__);
1340
1341         tty = buffer_get_string(m, NULL);
1342         if ((s = session_by_tty(tty)) != NULL)
1343                 mm_session_close(s);
1344         buffer_clear(m);
1345         xfree(tty);
1346         return (0);
1347 }
1348
1349 int
1350 mm_answer_sesskey(int sock, Buffer *m)
1351 {
1352         BIGNUM *p;
1353         int rsafail;
1354
1355         /* Turn off permissions */
1356         monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0);
1357
1358         if ((p = BN_new()) == NULL)
1359                 fatal("%s: BN_new", __func__);
1360
1361         buffer_get_bignum2(m, p);
1362
1363         rsafail = ssh1_session_key(p);
1364
1365         buffer_clear(m);
1366         buffer_put_int(m, rsafail);
1367         buffer_put_bignum2(m, p);
1368
1369         BN_clear_free(p);
1370
1371         mm_request_send(sock, MONITOR_ANS_SESSKEY, m);
1372
1373         /* Turn on permissions for sessid passing */
1374         monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1);
1375
1376         return (0);
1377 }
1378
1379 int
1380 mm_answer_sessid(int sock, Buffer *m)
1381 {
1382         int i;
1383
1384         debug3("%s entering", __func__);
1385
1386         if (buffer_len(m) != 16)
1387                 fatal("%s: bad ssh1 session id", __func__);
1388         for (i = 0; i < 16; i++)
1389                 session_id[i] = buffer_get_char(m);
1390
1391         /* Turn on permissions for getpwnam */
1392         monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
1393
1394         return (0);
1395 }
1396
1397 int
1398 mm_answer_rsa_keyallowed(int sock, Buffer *m)
1399 {
1400         BIGNUM *client_n;
1401         Key *key = NULL;
1402         u_char *blob = NULL;
1403         u_int blen = 0;
1404         int allowed = 0;
1405
1406         debug3("%s entering", __func__);
1407
1408         auth_method = "rsa";
1409         if (options.rsa_authentication && authctxt->valid) {
1410                 if ((client_n = BN_new()) == NULL)
1411                         fatal("%s: BN_new", __func__);
1412                 buffer_get_bignum2(m, client_n);
1413                 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key);
1414                 BN_clear_free(client_n);
1415         }
1416         buffer_clear(m);
1417         buffer_put_int(m, allowed);
1418         buffer_put_int(m, forced_command != NULL);
1419
1420         /* clear temporarily storage (used by generate challenge) */
1421         monitor_reset_key_state();
1422
1423         if (allowed && key != NULL) {
1424                 key->type = KEY_RSA;    /* cheat for key_to_blob */
1425                 if (key_to_blob(key, &blob, &blen) == 0)
1426                         fatal("%s: key_to_blob failed", __func__);
1427                 buffer_put_string(m, blob, blen);
1428
1429                 /* Save temporarily for comparison in verify */
1430                 key_blob = blob;
1431                 key_bloblen = blen;
1432                 key_blobtype = MM_RSAUSERKEY;
1433         }
1434         if (key != NULL)
1435                 key_free(key);
1436
1437         mm_append_debug(m);
1438
1439         mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m);
1440
1441         monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1442         monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0);
1443         return (0);
1444 }
1445
1446 int
1447 mm_answer_rsa_challenge(int sock, Buffer *m)
1448 {
1449         Key *key = NULL;
1450         u_char *blob;
1451         u_int blen;
1452
1453         debug3("%s entering", __func__);
1454
1455         if (!authctxt->valid)
1456                 fatal("%s: authctxt not valid", __func__);
1457         blob = buffer_get_string(m, &blen);
1458         if (!monitor_allowed_key(blob, blen))
1459                 fatal("%s: bad key, not previously allowed", __func__);
1460         if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1461                 fatal("%s: key type mismatch", __func__);
1462         if ((key = key_from_blob(blob, blen)) == NULL)
1463                 fatal("%s: received bad key", __func__);
1464
1465         if (ssh1_challenge)
1466                 BN_clear_free(ssh1_challenge);
1467         ssh1_challenge = auth_rsa_generate_challenge(key);
1468
1469         buffer_clear(m);
1470         buffer_put_bignum2(m, ssh1_challenge);
1471
1472         debug3("%s sending reply", __func__);
1473         mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m);
1474
1475         monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1);
1476
1477         xfree(blob);
1478         key_free(key);
1479         return (0);
1480 }
1481
1482 int
1483 mm_answer_rsa_response(int sock, Buffer *m)
1484 {
1485         Key *key = NULL;
1486         u_char *blob, *response;
1487         u_int blen, len;
1488         int success;
1489
1490         debug3("%s entering", __func__);
1491
1492         if (!authctxt->valid)
1493                 fatal("%s: authctxt not valid", __func__);
1494         if (ssh1_challenge == NULL)
1495                 fatal("%s: no ssh1_challenge", __func__);
1496
1497         blob = buffer_get_string(m, &blen);
1498         if (!monitor_allowed_key(blob, blen))
1499                 fatal("%s: bad key, not previously allowed", __func__);
1500         if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1501                 fatal("%s: key type mismatch: %d", __func__, key_blobtype);
1502         if ((key = key_from_blob(blob, blen)) == NULL)
1503                 fatal("%s: received bad key", __func__);
1504         response = buffer_get_string(m, &len);
1505         if (len != 16)
1506                 fatal("%s: received bad response to challenge", __func__);
1507         success = auth_rsa_verify_response(key, ssh1_challenge, response);
1508
1509         xfree(blob);
1510         key_free(key);
1511         xfree(response);
1512
1513         auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa";
1514
1515         /* reset state */
1516         BN_clear_free(ssh1_challenge);
1517         ssh1_challenge = NULL;
1518         monitor_reset_key_state();
1519
1520         buffer_clear(m);
1521         buffer_put_int(m, success);
1522         mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m);
1523
1524         return (success);
1525 }
1526
1527 int
1528 mm_answer_term(int sock, Buffer *req)
1529 {
1530         extern struct monitor *pmonitor;
1531         int res, status;
1532
1533         debug3("%s: tearing down sessions", __func__);
1534
1535         /* The child is terminating */
1536         session_destroy_all(&mm_session_close);
1537
1538         while (waitpid(pmonitor->m_pid, &status, 0) == -1)
1539                 if (errno != EINTR)
1540                         exit(1);
1541
1542         res = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
1543
1544         /* Terminate process */
1545         exit(res);
1546 }
1547
1548 #ifdef SSH_AUDIT_EVENTS
1549 /* Report that an audit event occurred */
1550 int
1551 mm_answer_audit_event(int socket, Buffer *m)
1552 {
1553         ssh_audit_event_t event;
1554
1555         debug3("%s entering", __func__);
1556
1557         event = buffer_get_int(m);
1558         switch(event) {
1559         case SSH_AUTH_FAIL_PUBKEY:
1560         case SSH_AUTH_FAIL_HOSTBASED:
1561         case SSH_AUTH_FAIL_GSSAPI:
1562         case SSH_LOGIN_EXCEED_MAXTRIES:
1563         case SSH_LOGIN_ROOT_DENIED:
1564         case SSH_CONNECTION_CLOSE:
1565         case SSH_INVALID_USER:
1566                 audit_event(event);
1567                 break;
1568         default:
1569                 fatal("Audit event type %d not permitted", event);
1570         }
1571
1572         return (0);
1573 }
1574
1575 int
1576 mm_answer_audit_command(int socket, Buffer *m)
1577 {
1578         u_int len;
1579         char *cmd;
1580
1581         debug3("%s entering", __func__);
1582         cmd = buffer_get_string(m, &len);
1583         /* sanity check command, if so how? */
1584         audit_run_command(cmd);
1585         xfree(cmd);
1586         return (0);
1587 }
1588 #endif /* SSH_AUDIT_EVENTS */
1589
1590 void
1591 monitor_apply_keystate(struct monitor *pmonitor)
1592 {
1593         if (compat20) {
1594                 set_newkeys(MODE_IN);
1595                 set_newkeys(MODE_OUT);
1596         } else {
1597                 packet_set_protocol_flags(child_state.ssh1protoflags);
1598                 packet_set_encryption_key(child_state.ssh1key,
1599                     child_state.ssh1keylen, child_state.ssh1cipher);
1600                 xfree(child_state.ssh1key);
1601         }
1602
1603         /* for rc4 and other stateful ciphers */
1604         packet_set_keycontext(MODE_OUT, child_state.keyout);
1605         xfree(child_state.keyout);
1606         packet_set_keycontext(MODE_IN, child_state.keyin);
1607         xfree(child_state.keyin);
1608
1609         if (!compat20) {
1610                 packet_set_iv(MODE_OUT, child_state.ivout);
1611                 xfree(child_state.ivout);
1612                 packet_set_iv(MODE_IN, child_state.ivin);
1613                 xfree(child_state.ivin);
1614         }
1615
1616         memcpy(&incoming_stream, &child_state.incoming,
1617             sizeof(incoming_stream));
1618         memcpy(&outgoing_stream, &child_state.outgoing,
1619             sizeof(outgoing_stream));
1620
1621         /* Update with new address */
1622         if (options.compression)
1623                 mm_init_compression(pmonitor->m_zlib);
1624
1625         /* Network I/O buffers */
1626         /* XXX inefficient for large buffers, need: buffer_init_from_string */
1627         buffer_clear(&input);
1628         buffer_append(&input, child_state.input, child_state.ilen);
1629         memset(child_state.input, 0, child_state.ilen);
1630         xfree(child_state.input);
1631
1632         buffer_clear(&output);
1633         buffer_append(&output, child_state.output, child_state.olen);
1634         memset(child_state.output, 0, child_state.olen);
1635         xfree(child_state.output);
1636 }
1637
1638 static Kex *
1639 mm_get_kex(Buffer *m)
1640 {
1641         Kex *kex;
1642         void *blob;
1643         u_int bloblen;
1644
1645         kex = xcalloc(1, sizeof(*kex));
1646         kex->session_id = buffer_get_string(m, &kex->session_id_len);
1647         if ((session_id2 == NULL) ||
1648             (kex->session_id_len != session_id2_len) ||
1649             (memcmp(kex->session_id, session_id2, session_id2_len) != 0))
1650                 fatal("mm_get_get: internal error: bad session id");
1651         kex->we_need = buffer_get_int(m);
1652         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1653         kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1654         kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1655         kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1656         kex->server = 1;
1657         kex->hostkey_type = buffer_get_int(m);
1658         kex->kex_type = buffer_get_int(m);
1659         blob = buffer_get_string(m, &bloblen);
1660         buffer_init(&kex->my);
1661         buffer_append(&kex->my, blob, bloblen);
1662         xfree(blob);
1663         blob = buffer_get_string(m, &bloblen);
1664         buffer_init(&kex->peer);
1665         buffer_append(&kex->peer, blob, bloblen);
1666         xfree(blob);
1667         kex->done = 1;
1668         kex->flags = buffer_get_int(m);
1669         kex->client_version_string = buffer_get_string(m, NULL);
1670         kex->server_version_string = buffer_get_string(m, NULL);
1671         kex->load_host_key=&get_hostkey_by_type;
1672         kex->host_key_index=&get_hostkey_index;
1673
1674         return (kex);
1675 }
1676
1677 /* This function requries careful sanity checking */
1678
1679 void
1680 mm_get_keystate(struct monitor *pmonitor)
1681 {
1682         Buffer m;
1683         u_char *blob, *p;
1684         u_int bloblen, plen;
1685         u_int32_t seqnr, packets;
1686         u_int64_t blocks;
1687
1688         debug3("%s: Waiting for new keys", __func__);
1689
1690         buffer_init(&m);
1691         mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, &m);
1692         if (!compat20) {
1693                 child_state.ssh1protoflags = buffer_get_int(&m);
1694                 child_state.ssh1cipher = buffer_get_int(&m);
1695                 child_state.ssh1key = buffer_get_string(&m,
1696                     &child_state.ssh1keylen);
1697                 child_state.ivout = buffer_get_string(&m,
1698                     &child_state.ivoutlen);
1699                 child_state.ivin = buffer_get_string(&m, &child_state.ivinlen);
1700                 goto skip;
1701         } else {
1702                 /* Get the Kex for rekeying */
1703                 *pmonitor->m_pkex = mm_get_kex(&m);
1704         }
1705
1706         blob = buffer_get_string(&m, &bloblen);
1707         current_keys[MODE_OUT] = mm_newkeys_from_blob(blob, bloblen);
1708         xfree(blob);
1709
1710         debug3("%s: Waiting for second key", __func__);
1711         blob = buffer_get_string(&m, &bloblen);
1712         current_keys[MODE_IN] = mm_newkeys_from_blob(blob, bloblen);
1713         xfree(blob);
1714
1715         /* Now get sequence numbers for the packets */
1716         seqnr = buffer_get_int(&m);
1717         blocks = buffer_get_int64(&m);
1718         packets = buffer_get_int(&m);
1719         packet_set_state(MODE_OUT, seqnr, blocks, packets);
1720         seqnr = buffer_get_int(&m);
1721         blocks = buffer_get_int64(&m);
1722         packets = buffer_get_int(&m);
1723         packet_set_state(MODE_IN, seqnr, blocks, packets);
1724
1725  skip:
1726         /* Get the key context */
1727         child_state.keyout = buffer_get_string(&m, &child_state.keyoutlen);
1728         child_state.keyin  = buffer_get_string(&m, &child_state.keyinlen);
1729
1730         debug3("%s: Getting compression state", __func__);
1731         /* Get compression state */
1732         p = buffer_get_string(&m, &plen);
1733         if (plen != sizeof(child_state.outgoing))
1734                 fatal("%s: bad request size", __func__);
1735         memcpy(&child_state.outgoing, p, sizeof(child_state.outgoing));
1736         xfree(p);
1737
1738         p = buffer_get_string(&m, &plen);
1739         if (plen != sizeof(child_state.incoming))
1740                 fatal("%s: bad request size", __func__);
1741         memcpy(&child_state.incoming, p, sizeof(child_state.incoming));
1742         xfree(p);
1743
1744         /* Network I/O buffers */
1745         debug3("%s: Getting Network I/O buffers", __func__);
1746         child_state.input = buffer_get_string(&m, &child_state.ilen);
1747         child_state.output = buffer_get_string(&m, &child_state.olen);
1748
1749         buffer_free(&m);
1750 }
1751
1752
1753 /* Allocation functions for zlib */
1754 void *
1755 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size)
1756 {
1757         size_t len = (size_t) size * ncount;
1758         void *address;
1759
1760         if (len == 0 || ncount > SIZE_T_MAX / size)
1761                 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size);
1762
1763         address = mm_malloc(mm, len);
1764
1765         return (address);
1766 }
1767
1768 void
1769 mm_zfree(struct mm_master *mm, void *address)
1770 {
1771         mm_free(mm, address);
1772 }
1773
1774 void
1775 mm_init_compression(struct mm_master *mm)
1776 {
1777         outgoing_stream.zalloc = (alloc_func)mm_zalloc;
1778         outgoing_stream.zfree = (free_func)mm_zfree;
1779         outgoing_stream.opaque = mm;
1780
1781         incoming_stream.zalloc = (alloc_func)mm_zalloc;
1782         incoming_stream.zfree = (free_func)mm_zfree;
1783         incoming_stream.opaque = mm;
1784 }
1785
1786 /* XXX */
1787
1788 #define FD_CLOSEONEXEC(x) do { \
1789         if (fcntl(x, F_SETFD, 1) == -1) \
1790                 fatal("fcntl(%d, F_SETFD)", x); \
1791 } while (0)
1792
1793 static void
1794 monitor_socketpair(int *pair)
1795 {
1796 #ifdef HAVE_SOCKETPAIR
1797         if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
1798                 fatal("%s: socketpair", __func__);
1799 #else
1800         fatal("%s: UsePrivilegeSeparation=yes not supported",
1801             __func__);
1802 #endif
1803         FD_CLOSEONEXEC(pair[0]);
1804         FD_CLOSEONEXEC(pair[1]);
1805 }
1806
1807 #define MM_MEMSIZE      65536
1808
1809 struct monitor *
1810 monitor_init(void)
1811 {
1812         struct monitor *mon;
1813         int pair[2];
1814
1815         mon = xcalloc(1, sizeof(*mon));
1816
1817         monitor_socketpair(pair);
1818
1819         mon->m_recvfd = pair[0];
1820         mon->m_sendfd = pair[1];
1821
1822         /* Used to share zlib space across processes */
1823         if (options.compression) {
1824                 mon->m_zback = mm_create(NULL, MM_MEMSIZE);
1825                 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE);
1826
1827                 /* Compression needs to share state across borders */
1828                 mm_init_compression(mon->m_zlib);
1829         }
1830
1831         return mon;
1832 }
1833
1834 void
1835 monitor_reinit(struct monitor *mon)
1836 {
1837         int pair[2];
1838
1839         monitor_socketpair(pair);
1840
1841         mon->m_recvfd = pair[0];
1842         mon->m_sendfd = pair[1];
1843 }
1844
1845 #ifdef GSSAPI
1846 int
1847 mm_answer_gss_setup_ctx(int sock, Buffer *m)
1848 {
1849         gss_OID_desc goid;
1850         OM_uint32 major;
1851         u_int len;
1852
1853         goid.elements = buffer_get_string(m, &len);
1854         goid.length = len;
1855
1856         major = ssh_gssapi_server_ctx(&gsscontext, &goid);
1857
1858         xfree(goid.elements);
1859
1860         buffer_clear(m);
1861         buffer_put_int(m, major);
1862
1863         mm_request_send(sock, MONITOR_ANS_GSSSETUP, m);
1864
1865         /* Now we have a context, enable the step */
1866         monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1);
1867
1868         return (0);
1869 }
1870
1871 int
1872 mm_answer_gss_accept_ctx(int sock, Buffer *m)
1873 {
1874         gss_buffer_desc in;
1875         gss_buffer_desc out = GSS_C_EMPTY_BUFFER;
1876         OM_uint32 major, minor;
1877         OM_uint32 flags = 0; /* GSI needs this */
1878         u_int len;
1879
1880         in.value = buffer_get_string(m, &len);
1881         in.length = len;
1882         major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
1883         xfree(in.value);
1884
1885         buffer_clear(m);
1886         buffer_put_int(m, major);
1887         buffer_put_string(m, out.value, out.length);
1888         buffer_put_int(m, flags);
1889         mm_request_send(sock, MONITOR_ANS_GSSSTEP, m);
1890
1891         gss_release_buffer(&minor, &out);
1892
1893         if (major == GSS_S_COMPLETE) {
1894                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
1895                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1896                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
1897         }
1898         return (0);
1899 }
1900
1901 int
1902 mm_answer_gss_checkmic(int sock, Buffer *m)
1903 {
1904         gss_buffer_desc gssbuf, mic;
1905         OM_uint32 ret;
1906         u_int len;
1907
1908         gssbuf.value = buffer_get_string(m, &len);
1909         gssbuf.length = len;
1910         mic.value = buffer_get_string(m, &len);
1911         mic.length = len;
1912
1913         ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic);
1914
1915         xfree(gssbuf.value);
1916         xfree(mic.value);
1917
1918         buffer_clear(m);
1919         buffer_put_int(m, ret);
1920
1921         mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m);
1922
1923         if (!GSS_ERROR(ret))
1924                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1925
1926         return (0);
1927 }
1928
1929 int
1930 mm_answer_gss_userok(int sock, Buffer *m)
1931 {
1932         int authenticated;
1933
1934         authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
1935
1936         buffer_clear(m);
1937         buffer_put_int(m, authenticated);
1938
1939         debug3("%s: sending result %d", __func__, authenticated);
1940         mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
1941
1942         auth_method = "gssapi-with-mic";
1943
1944         /* Monitor loop will terminate if authenticated */
1945         return (authenticated);
1946 }
1947 #endif /* GSSAPI */