monitor.c

   1 /* $OpenBSD: monitor.c,v 1.77 2006/03/30 11:40:21 dtucker 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/wait.h>
  32
  33 #ifdef HAVE_PATHS_H
  34 #include <paths.h>
  35 #endif
  36 #include <signal.h>
  37
  38 #ifdef SKEY
  39 #include <skey.h>
  40 #endif
  41
  42 #include <openssl/dh.h>
  43
  44 #include "ssh.h"
  45 #include "auth.h"
  46 #include "kex.h"
  47 #include "dh.h"
  48 #ifdef TARGET_OS_MAC    /* XXX Broken krb5 headers on Mac */
  49 #undef TARGET_OS_MAC
  50 #include "zlib.h"
  51 #define TARGET_OS_MAC 1
  52 #else
  53 #include "zlib.h"
  54 #endif
  55 #include "packet.h"
  56 #include "auth-options.h"
  57 #include "sshpty.h"
  58 #include "channels.h"
  59 #include "session.h"
  60 #include "sshlogin.h"
  61 #include "canohost.h"
  62 #include "log.h"
  63 #include "servconf.h"
  64 #include "monitor.h"
  65 #include "monitor_mm.h"
  66 #include "monitor_wrap.h"
  67 #include "monitor_fdpass.h"
  68 #include "xmalloc.h"
  69 #include "misc.h"
  70 #include "buffer.h"
  71 #include "bufaux.h"
  72 #include "compat.h"
  73 #include "ssh2.h"
  74
  75 #ifdef GSSAPI
  76 #include "ssh-gss.h"
  77 static Gssctxt *gsscontext = NULL;
  78 #endif
  79
  80 /* Imports */
  81 extern ServerOptions options;
  82 extern u_int utmp_len;
  83 extern Newkeys *current_keys[];
  84 extern z_stream incoming_stream;
  85 extern z_stream outgoing_stream;
  86 extern u_char session_id[];
  87 extern Buffer input, output;
  88 extern Buffer auth_debug;
  89 extern int auth_debug_init;
  90 extern Buffer loginmsg;
  91
  92 /* State exported from the child */
  93
  94 struct {
  95         z_stream incoming;
  96         z_stream outgoing;
  97         u_char *keyin;
  98         u_int keyinlen;
  99         u_char *keyout;
 100         u_int keyoutlen;
 101         u_char *ivin;
 102         u_int ivinlen;
 103         u_char *ivout;
 104         u_int ivoutlen;
 105         u_char *ssh1key;
 106         u_int ssh1keylen;
 107         int ssh1cipher;
 108         int ssh1protoflags;
 109         u_char *input;
 110         u_int ilen;
 111         u_char *output;
 112         u_int olen;
 113 } child_state;
 114
 115 /* Functions on the monitor that answer unprivileged requests */
 116
 117 int mm_answer_moduli(int, Buffer *);
 118 int mm_answer_sign(int, Buffer *);
 119 int mm_answer_pwnamallow(int, Buffer *);
 120 int mm_answer_auth2_read_banner(int, Buffer *);
 121 int mm_answer_authserv(int, Buffer *);
 122 int mm_answer_authpassword(int, Buffer *);
 123 int mm_answer_bsdauthquery(int, Buffer *);
 124 int mm_answer_bsdauthrespond(int, Buffer *);
 125 int mm_answer_skeyquery(int, Buffer *);
 126 int mm_answer_skeyrespond(int, Buffer *);
 127 int mm_answer_keyallowed(int, Buffer *);
 128 int mm_answer_keyverify(int, Buffer *);
 129 int mm_answer_pty(int, Buffer *);
 130 int mm_answer_pty_cleanup(int, Buffer *);
 131 int mm_answer_term(int, Buffer *);
 132 int mm_answer_rsa_keyallowed(int, Buffer *);
 133 int mm_answer_rsa_challenge(int, Buffer *);
 134 int mm_answer_rsa_response(int, Buffer *);
 135 int mm_answer_sesskey(int, Buffer *);
 136 int mm_answer_sessid(int, Buffer *);
 137
 138 #ifdef USE_PAM
 139 int mm_answer_pam_start(int, Buffer *);
 140 int mm_answer_pam_account(int, Buffer *);
 141 int mm_answer_pam_init_ctx(int, Buffer *);
 142 int mm_answer_pam_query(int, Buffer *);
 143 int mm_answer_pam_respond(int, Buffer *);
 144 int mm_answer_pam_free_ctx(int, Buffer *);
 145 #endif
 146
 147 #ifdef GSSAPI
 148 int mm_answer_gss_setup_ctx(int, Buffer *);
 149 int mm_answer_gss_accept_ctx(int, Buffer *);
 150 int mm_answer_gss_userok(int, Buffer *);
 151 int mm_answer_gss_checkmic(int, Buffer *);
 152 #endif
 153
 154 #ifdef SSH_AUDIT_EVENTS
 155 int mm_answer_audit_event(int, Buffer *);
 156 int mm_answer_audit_command(int, Buffer *);
 157 #endif
 158
 159 static Authctxt *authctxt;
 160 static BIGNUM *ssh1_challenge = NULL;   /* used for ssh1 rsa auth */
 161
 162 /* local state for key verify */
 163 static u_char *key_blob = NULL;
 164 static u_int key_bloblen = 0;
 165 static int key_blobtype = MM_NOKEY;
 166 static char *hostbased_cuser = NULL;
 167 static char *hostbased_chost = NULL;
 168 static char *auth_method = "unknown";
 169 static u_int session_id2_len = 0;
 170 static u_char *session_id2 = NULL;
 171 static pid_t monitor_child_pid;
 172
 173 struct mon_table {
 174         enum monitor_reqtype type;
 175         int flags;
 176         int (*f)(int, Buffer *);
 177 };
 178
 179 #define MON_ISAUTH      0x0004  /* Required for Authentication */
 180 #define MON_AUTHDECIDE  0x0008  /* Decides Authentication */
 181 #define MON_ONCE        0x0010  /* Disable after calling */
 182 #define MON_ALOG        0x0020  /* Log auth attempt without authenticating */
 183
 184 #define MON_AUTH        (MON_ISAUTH|MON_AUTHDECIDE)
 185
 186 #define MON_PERMIT      0x1000  /* Request is permitted */
 187
 188 struct mon_table mon_dispatch_proto20[] = {
 189     {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli},
 190     {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
 191     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
 192     {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
 193     {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
 194     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 195 #ifdef USE_PAM
 196     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
 197     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
 198     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
 199     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
 200     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
 201     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 202 #endif
 203 #ifdef SSH_AUDIT_EVENTS
 204     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 205 #endif
 206 #ifdef BSD_AUTH
 207     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
 208     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
 209 #endif
 210 #ifdef SKEY
 211     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
 212     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
 213 #endif
 214     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
 215     {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
 216 #ifdef GSSAPI
 217     {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx},
 218     {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx},
 219     {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok},
 220     {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic},
 221 #endif
 222     {0, 0, NULL}
 223 };
 224
 225 struct mon_table mon_dispatch_postauth20[] = {
 226     {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
 227     {MONITOR_REQ_SIGN, 0, mm_answer_sign},
 228     {MONITOR_REQ_PTY, 0, mm_answer_pty},
 229     {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
 230     {MONITOR_REQ_TERM, 0, mm_answer_term},
 231 #ifdef SSH_AUDIT_EVENTS
 232     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 233     {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
 234 #endif
 235     {0, 0, NULL}
 236 };
 237
 238 struct mon_table mon_dispatch_proto15[] = {
 239     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
 240     {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey},
 241     {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid},
 242     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 243     {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_rsa_keyallowed},
 244     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_keyallowed},
 245     {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge},
 246     {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response},
 247 #ifdef BSD_AUTH
 248     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
 249     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
 250 #endif
 251 #ifdef SKEY
 252     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
 253     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
 254 #endif
 255 #ifdef USE_PAM
 256     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
 257     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
 258     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
 259     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
 260     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
 261     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 262 #endif
 263 #ifdef SSH_AUDIT_EVENTS
 264     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 265 #endif
 266     {0, 0, NULL}
 267 };
 268
 269 struct mon_table mon_dispatch_postauth15[] = {
 270     {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty},
 271     {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup},
 272     {MONITOR_REQ_TERM, 0, mm_answer_term},
 273 #ifdef SSH_AUDIT_EVENTS
 274     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 275     {MONITOR_REQ_AUDIT_COMMAND, MON_ONCE, mm_answer_audit_command},
 276 #endif
 277     {0, 0, NULL}
 278 };
 279
 280 struct mon_table *mon_dispatch;
 281
 282 /* Specifies if a certain message is allowed at the moment */
 283
 284 static void
 285 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit)
 286 {
 287         while (ent->f != NULL) {
 288                 if (ent->type == type) {
 289                         ent->flags &= ~MON_PERMIT;
 290                         ent->flags |= permit ? MON_PERMIT : 0;
 291                         return;
 292                 }
 293                 ent++;
 294         }
 295 }
 296
 297 static void
 298 monitor_permit_authentications(int permit)
 299 {
 300         struct mon_table *ent = mon_dispatch;
 301
 302         while (ent->f != NULL) {
 303                 if (ent->flags & MON_AUTH) {
 304                         ent->flags &= ~MON_PERMIT;
 305                         ent->flags |= permit ? MON_PERMIT : 0;
 306                 }
 307                 ent++;
 308         }
 309 }
 310
 311 void
 312 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
 313 {
 314         struct mon_table *ent;
 315         int authenticated = 0;
 316
 317         debug3("preauth child monitor started");
 318
 319         authctxt = _authctxt;
 320         memset(authctxt, 0, sizeof(*authctxt));
 321
 322         authctxt->loginmsg = &loginmsg;
 323
 324         if (compat20) {
 325                 mon_dispatch = mon_dispatch_proto20;
 326
 327                 /* Permit requests for moduli and signatures */
 328                 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 329                 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 330         } else {
 331                 mon_dispatch = mon_dispatch_proto15;
 332
 333                 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1);
 334         }
 335
 336         /* The first few requests do not require asynchronous access */
 337         while (!authenticated) {
 338                 auth_method = "unknown";
 339                 authenticated = monitor_read(pmonitor, mon_dispatch, &ent);
 340                 if (authenticated) {
 341                         if (!(ent->flags & MON_AUTHDECIDE))
 342                                 fatal("%s: unexpected authentication from %d",
 343                                     __func__, ent->type);
 344                         if (authctxt->pw->pw_uid == 0 &&
 345                             !auth_root_allowed(auth_method))
 346                                 authenticated = 0;
 347 #ifdef USE_PAM
 348                         /* PAM needs to perform account checks after auth */
 349                         if (options.use_pam && authenticated) {
 350                                 Buffer m;
 351
 352                                 buffer_init(&m);
 353                                 mm_request_receive_expect(pmonitor->m_sendfd,
 354                                     MONITOR_REQ_PAM_ACCOUNT, &m);
 355                                 authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m);
 356                                 buffer_free(&m);
 357                         }
 358 #endif
 359                 }
 360
 361                 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
 362                         auth_log(authctxt, authenticated, auth_method,
 363                             compat20 ? " ssh2" : "");
 364                         if (!authenticated)
 365                                 authctxt->failures++;
 366                 }
 367         }
 368
 369         if (!authctxt->valid)
 370                 fatal("%s: authenticated invalid user", __func__);
 371         if (strcmp(auth_method, "unknown") == 0)
 372                 fatal("%s: authentication method name unknown", __func__);
 373
 374         debug("%s: %s has been authenticated by privileged process",
 375             __func__, authctxt->user);
 376
 377         mm_get_keystate(pmonitor);
 378 }
 379
 380 static void
 381 monitor_set_child_handler(pid_t pid)
 382 {
 383         monitor_child_pid = pid;
 384 }
 385
 386 static void
 387 monitor_child_handler(int sig)
 388 {
 389         kill(monitor_child_pid, sig);
 390 }
 391
 392 void
 393 monitor_child_postauth(struct monitor *pmonitor)
 394 {
 395         monitor_set_child_handler(pmonitor->m_pid);
 396         signal(SIGHUP, &monitor_child_handler);
 397         signal(SIGTERM, &monitor_child_handler);
 398
 399         if (compat20) {
 400                 mon_dispatch = mon_dispatch_postauth20;
 401
 402                 /* Permit requests for moduli and signatures */
 403                 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 404                 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 405                 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
 406         } else {
 407                 mon_dispatch = mon_dispatch_postauth15;
 408                 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
 409         }
 410         if (!no_pty_flag) {
 411                 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
 412                 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1);
 413         }
 414
 415         for (;;)
 416                 monitor_read(pmonitor, mon_dispatch, NULL);
 417 }
 418
 419 void
 420 monitor_sync(struct monitor *pmonitor)
 421 {
 422         if (options.compression) {
 423                 /* The member allocation is not visible, so sync it */
 424                 mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback);
 425         }
 426 }
 427
 428 int
 429 monitor_read(struct monitor *pmonitor, struct mon_table *ent,
 430     struct mon_table **pent)
 431 {
 432         Buffer m;
 433         int ret;
 434         u_char type;
 435
 436         buffer_init(&m);
 437
 438         mm_request_receive(pmonitor->m_sendfd, &m);
 439         type = buffer_get_char(&m);
 440
 441         debug3("%s: checking request %d", __func__, type);
 442
 443         while (ent->f != NULL) {
 444                 if (ent->type == type)
 445                         break;
 446                 ent++;
 447         }
 448
 449         if (ent->f != NULL) {
 450                 if (!(ent->flags & MON_PERMIT))
 451                         fatal("%s: unpermitted request %d", __func__,
 452                             type);
 453                 ret = (*ent->f)(pmonitor->m_sendfd, &m);
 454                 buffer_free(&m);
 455
 456                 /* The child may use this request only once, disable it */
 457                 if (ent->flags & MON_ONCE) {
 458                         debug2("%s: %d used once, disabling now", __func__,
 459                             type);
 460                         ent->flags &= ~MON_PERMIT;
 461                 }
 462
 463                 if (pent != NULL)
 464                         *pent = ent;
 465
 466                 return ret;
 467         }
 468
 469         fatal("%s: unsupported request: %d", __func__, type);
 470
 471         /* NOTREACHED */
 472         return (-1);
 473 }
 474
 475 /* allowed key state */
 476 static int
 477 monitor_allowed_key(u_char *blob, u_int bloblen)
 478 {
 479         /* make sure key is allowed */
 480         if (key_blob == NULL || key_bloblen != bloblen ||
 481             memcmp(key_blob, blob, key_bloblen))
 482                 return (0);
 483         return (1);
 484 }
 485
 486 static void
 487 monitor_reset_key_state(void)
 488 {
 489         /* reset state */
 490         if (key_blob != NULL)
 491                 xfree(key_blob);
 492         if (hostbased_cuser != NULL)
 493                 xfree(hostbased_cuser);
 494         if (hostbased_chost != NULL)
 495                 xfree(hostbased_chost);
 496         key_blob = NULL;
 497         key_bloblen = 0;
 498         key_blobtype = MM_NOKEY;
 499         hostbased_cuser = NULL;
 500         hostbased_chost = NULL;
 501 }
 502
 503 int
 504 mm_answer_moduli(int sock, Buffer *m)
 505 {
 506         DH *dh;
 507         int min, want, max;
 508
 509         min = buffer_get_int(m);
 510         want = buffer_get_int(m);
 511         max = buffer_get_int(m);
 512
 513         debug3("%s: got parameters: %d %d %d",
 514             __func__, min, want, max);
 515         /* We need to check here, too, in case the child got corrupted */
 516         if (max < min || want < min || max < want)
 517                 fatal("%s: bad parameters: %d %d %d",
 518                     __func__, min, want, max);
 519
 520         buffer_clear(m);
 521
 522         dh = choose_dh(min, want, max);
 523         if (dh == NULL) {
 524                 buffer_put_char(m, 0);
 525                 return (0);
 526         } else {
 527                 /* Send first bignum */
 528                 buffer_put_char(m, 1);
 529                 buffer_put_bignum2(m, dh->p);
 530                 buffer_put_bignum2(m, dh->g);
 531
 532                 DH_free(dh);
 533         }
 534         mm_request_send(sock, MONITOR_ANS_MODULI, m);
 535         return (0);
 536 }
 537
 538 int
 539 mm_answer_sign(int sock, Buffer *m)
 540 {
 541         Key *key;
 542         u_char *p;
 543         u_char *signature;
 544         u_int siglen, datlen;
 545         int keyid;
 546
 547         debug3("%s", __func__);
 548
 549         keyid = buffer_get_int(m);
 550         p = buffer_get_string(m, &datlen);
 551
 552         /*
 553          * Supported KEX types will only return SHA1 (20 byte) or
 554          * SHA256 (32 byte) hashes
 555          */
 556         if (datlen != 20 && datlen != 32)
 557                 fatal("%s: data length incorrect: %u", __func__, datlen);
 558
 559         /* save session id, it will be passed on the first call */
 560         if (session_id2_len == 0) {
 561                 session_id2_len = datlen;
 562                 session_id2 = xmalloc(session_id2_len);
 563                 memcpy(session_id2, p, session_id2_len);
 564         }
 565
 566         if ((key = get_hostkey_by_index(keyid)) == NULL)
 567                 fatal("%s: no hostkey from index %d", __func__, keyid);
 568         if (key_sign(key, &signature, &siglen, p, datlen) < 0)
 569                 fatal("%s: key_sign failed", __func__);
 570
 571         debug3("%s: signature %p(%u)", __func__, signature, siglen);
 572
 573         buffer_clear(m);
 574         buffer_put_string(m, signature, siglen);
 575
 576         xfree(p);
 577         xfree(signature);
 578
 579         mm_request_send(sock, MONITOR_ANS_SIGN, m);
 580
 581         /* Turn on permissions for getpwnam */
 582         monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
 583
 584         return (0);
 585 }
 586
 587 /* Retrieves the password entry and also checks if the user is permitted */
 588
 589 int
 590 mm_answer_pwnamallow(int sock, Buffer *m)
 591 {
 592         char *username;
 593         struct passwd *pwent;
 594         int allowed = 0;
 595
 596         debug3("%s", __func__);
 597
 598         if (authctxt->attempt++ != 0)
 599                 fatal("%s: multiple attempts for getpwnam", __func__);
 600
 601         username = buffer_get_string(m, NULL);
 602
 603         pwent = getpwnamallow(username);
 604
 605         authctxt->user = xstrdup(username);
 606         setproctitle("%s [priv]", pwent ? username : "unknown");
 607         xfree(username);
 608
 609         buffer_clear(m);
 610
 611         if (pwent == NULL) {
 612                 buffer_put_char(m, 0);
 613                 authctxt->pw = fakepw();
 614                 goto out;
 615         }
 616
 617         allowed = 1;
 618         authctxt->pw = pwent;
 619         authctxt->valid = 1;
 620
 621         buffer_put_char(m, 1);
 622         buffer_put_string(m, pwent, sizeof(struct passwd));
 623         buffer_put_cstring(m, pwent->pw_name);
 624         buffer_put_cstring(m, "*");
 625         buffer_put_cstring(m, pwent->pw_gecos);
 626 #ifdef HAVE_PW_CLASS_IN_PASSWD
 627         buffer_put_cstring(m, pwent->pw_class);
 628 #endif
 629         buffer_put_cstring(m, pwent->pw_dir);
 630         buffer_put_cstring(m, pwent->pw_shell);
 631
 632  out:
 633         debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed);
 634         mm_request_send(sock, MONITOR_ANS_PWNAM, m);
 635
 636         /* For SSHv1 allow authentication now */
 637         if (!compat20)
 638                 monitor_permit_authentications(1);
 639         else {
 640                 /* Allow service/style information on the auth context */
 641                 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
 642                 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
 643         }
 644
 645 #ifdef USE_PAM
 646         if (options.use_pam)
 647                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
 648 #endif
 649 #ifdef SSH_AUDIT_EVENTS
 650         monitor_permit(mon_dispatch, MONITOR_REQ_AUDIT_COMMAND, 1);
 651 #endif
 652
 653         return (0);
 654 }
 655
 656 int mm_answer_auth2_read_banner(int sock, Buffer *m)
 657 {
 658         char *banner;
 659
 660         buffer_clear(m);
 661         banner = auth2_read_banner();
 662         buffer_put_cstring(m, banner != NULL ? banner : "");
 663         mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m);
 664
 665         if (banner != NULL)
 666                 xfree(banner);
 667
 668         return (0);
 669 }
 670
 671 int
 672 mm_answer_authserv(int sock, Buffer *m)
 673 {
 674         monitor_permit_authentications(1);
 675
 676         authctxt->service = buffer_get_string(m, NULL);
 677         authctxt->style = buffer_get_string(m, NULL);
 678         debug3("%s: service=%s, style=%s",
 679             __func__, authctxt->service, authctxt->style);
 680
 681         if (strlen(authctxt->style) == 0) {
 682                 xfree(authctxt->style);
 683                 authctxt->style = NULL;
 684         }
 685
 686         return (0);
 687 }
 688
 689 int
 690 mm_answer_authpassword(int sock, Buffer *m)
 691 {
 692         static int call_count;
 693         char *passwd;
 694         int authenticated;
 695         u_int plen;
 696
 697         passwd = buffer_get_string(m, &plen);
 698         /* Only authenticate if the context is valid */
 699         authenticated = options.password_authentication &&
 700             auth_password(authctxt, passwd);
 701         memset(passwd, 0, strlen(passwd));
 702         xfree(passwd);
 703
 704         buffer_clear(m);
 705         buffer_put_int(m, authenticated);
 706
 707         debug3("%s: sending result %d", __func__, authenticated);
 708         mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m);
 709
 710         call_count++;
 711         if (plen == 0 && call_count == 1)
 712                 auth_method = "none";
 713         else
 714                 auth_method = "password";
 715
 716         /* Causes monitor loop to terminate if authenticated */
 717         return (authenticated);
 718 }
 719
 720 #ifdef BSD_AUTH
 721 int
 722 mm_answer_bsdauthquery(int sock, Buffer *m)
 723 {
 724         char *name, *infotxt;
 725         u_int numprompts;
 726         u_int *echo_on;
 727         char **prompts;
 728         u_int success;
 729
 730         success = bsdauth_query(authctxt, &name, &infotxt, &numprompts,
 731             &prompts, &echo_on) < 0 ? 0 : 1;
 732
 733         buffer_clear(m);
 734         buffer_put_int(m, success);
 735         if (success)
 736                 buffer_put_cstring(m, prompts[0]);
 737
 738         debug3("%s: sending challenge success: %u", __func__, success);
 739         mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m);
 740
 741         if (success) {
 742                 xfree(name);
 743                 xfree(infotxt);
 744                 xfree(prompts);
 745                 xfree(echo_on);
 746         }
 747
 748         return (0);
 749 }
 750
 751 int
 752 mm_answer_bsdauthrespond(int sock, Buffer *m)
 753 {
 754         char *response;
 755         int authok;
 756
 757         if (authctxt->as == 0)
 758                 fatal("%s: no bsd auth session", __func__);
 759
 760         response = buffer_get_string(m, NULL);
 761         authok = options.challenge_response_authentication &&
 762             auth_userresponse(authctxt->as, response, 0);
 763         authctxt->as = NULL;
 764         debug3("%s: <%s> = <%d>", __func__, response, authok);
 765         xfree(response);
 766
 767         buffer_clear(m);
 768         buffer_put_int(m, authok);
 769
 770         debug3("%s: sending authenticated: %d", __func__, authok);
 771         mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
 772
 773         auth_method = "bsdauth";
 774
 775         return (authok != 0);
 776 }
 777 #endif
 778
 779 #ifdef SKEY
 780 int
 781 mm_answer_skeyquery(int sock, Buffer *m)
 782 {
 783         struct skey skey;
 784         char challenge[1024];
 785         u_int success;
 786
 787         success = _compat_skeychallenge(&skey, authctxt->user, challenge,
 788             sizeof(challenge)) < 0 ? 0 : 1;
 789
 790         buffer_clear(m);
 791         buffer_put_int(m, success);
 792         if (success)
 793                 buffer_put_cstring(m, challenge);
 794
 795         debug3("%s: sending challenge success: %u", __func__, success);
 796         mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m);
 797
 798         return (0);
 799 }
 800
 801 int
 802 mm_answer_skeyrespond(int sock, Buffer *m)
 803 {
 804         char *response;
 805         int authok;
 806
 807         response = buffer_get_string(m, NULL);
 808
 809         authok = (options.challenge_response_authentication &&
 810             authctxt->valid &&
 811             skey_haskey(authctxt->pw->pw_name) == 0 &&
 812             skey_passcheck(authctxt->pw->pw_name, response) != -1);
 813
 814         xfree(response);
 815
 816         buffer_clear(m);
 817         buffer_put_int(m, authok);
 818
 819         debug3("%s: sending authenticated: %d", __func__, authok);
 820         mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m);
 821
 822         auth_method = "skey";
 823
 824         return (authok != 0);
 825 }
 826 #endif
 827
 828 #ifdef USE_PAM
 829 int
 830 mm_answer_pam_start(int sock, Buffer *m)
 831 {
 832         if (!options.use_pam)
 833                 fatal("UsePAM not set, but ended up in %s anyway", __func__);
 834
 835         start_pam(authctxt);
 836
 837         monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1);
 838
 839         return (0);
 840 }
 841
 842 int
 843 mm_answer_pam_account(int sock, Buffer *m)
 844 {
 845         u_int ret;
 846
 847         if (!options.use_pam)
 848                 fatal("UsePAM not set, but ended up in %s anyway", __func__);
 849
 850         ret = do_pam_account();
 851
 852         buffer_put_int(m, ret);
 853         buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
 854
 855         mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m);
 856
 857         return (ret);
 858 }
 859
 860 static void *sshpam_ctxt, *sshpam_authok;
 861 extern KbdintDevice sshpam_device;
 862
 863 int
 864 mm_answer_pam_init_ctx(int sock, Buffer *m)
 865 {
 866
 867         debug3("%s", __func__);
 868         authctxt->user = buffer_get_string(m, NULL);
 869         sshpam_ctxt = (sshpam_device.init_ctx)(authctxt);
 870         sshpam_authok = NULL;
 871         buffer_clear(m);
 872         if (sshpam_ctxt != NULL) {
 873                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
 874                 buffer_put_int(m, 1);
 875         } else {
 876                 buffer_put_int(m, 0);
 877         }
 878         mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m);
 879         return (0);
 880 }
 881
 882 int
 883 mm_answer_pam_query(int sock, Buffer *m)
 884 {
 885         char *name, *info, **prompts;
 886         u_int i, num, *echo_on;
 887         int ret;
 888
 889         debug3("%s", __func__);
 890         sshpam_authok = NULL;
 891         ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, &num, &prompts, &echo_on);
 892         if (ret == 0 && num == 0)
 893                 sshpam_authok = sshpam_ctxt;
 894         if (num > 1 || name == NULL || info == NULL)
 895                 ret = -1;
 896         buffer_clear(m);
 897         buffer_put_int(m, ret);
 898         buffer_put_cstring(m, name);
 899         xfree(name);
 900         buffer_put_cstring(m, info);
 901         xfree(info);
 902         buffer_put_int(m, num);
 903         for (i = 0; i < num; ++i) {
 904                 buffer_put_cstring(m, prompts[i]);
 905                 xfree(prompts[i]);
 906                 buffer_put_int(m, echo_on[i]);
 907         }
 908         if (prompts != NULL)
 909                 xfree(prompts);
 910         if (echo_on != NULL)
 911                 xfree(echo_on);
 912         auth_method = "keyboard-interactive/pam";
 913         mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m);
 914         return (0);
 915 }
 916
 917 int
 918 mm_answer_pam_respond(int sock, Buffer *m)
 919 {
 920         char **resp;
 921         u_int i, num;
 922         int ret;
 923
 924         debug3("%s", __func__);
 925         sshpam_authok = NULL;
 926         num = buffer_get_int(m);
 927         if (num > 0) {
 928                 resp = xcalloc(num, sizeof(char *));
 929                 for (i = 0; i < num; ++i)
 930                         resp[i] = buffer_get_string(m, NULL);
 931                 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp);
 932                 for (i = 0; i < num; ++i)
 933                         xfree(resp[i]);
 934                 xfree(resp);
 935         } else {
 936                 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL);
 937         }
 938         buffer_clear(m);
 939         buffer_put_int(m, ret);
 940         mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m);
 941         auth_method = "keyboard-interactive/pam";
 942         if (ret == 0)
 943                 sshpam_authok = sshpam_ctxt;
 944         return (0);
 945 }
 946
 947 int
 948 mm_answer_pam_free_ctx(int sock, Buffer *m)
 949 {
 950
 951         debug3("%s", __func__);
 952         (sshpam_device.free_ctx)(sshpam_ctxt);
 953         buffer_clear(m);
 954         mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m);
 955         auth_method = "keyboard-interactive/pam";
 956         return (sshpam_authok == sshpam_ctxt);
 957 }
 958 #endif
 959
 960 static void
 961 mm_append_debug(Buffer *m)
 962 {
 963         if (auth_debug_init && buffer_len(&auth_debug)) {
 964                 debug3("%s: Appending debug messages for child", __func__);
 965                 buffer_append(m, buffer_ptr(&auth_debug),
 966                     buffer_len(&auth_debug));
 967                 buffer_clear(&auth_debug);
 968         }
 969 }
 970
 971 int
 972 mm_answer_keyallowed(int sock, Buffer *m)
 973 {
 974         Key *key;
 975         char *cuser, *chost;
 976         u_char *blob;
 977         u_int bloblen;
 978         enum mm_keytype type = 0;
 979         int allowed = 0;
 980
 981         debug3("%s entering", __func__);
 982
 983         type = buffer_get_int(m);
 984         cuser = buffer_get_string(m, NULL);
 985         chost = buffer_get_string(m, NULL);
 986         blob = buffer_get_string(m, &bloblen);
 987
 988         key = key_from_blob(blob, bloblen);
 989
 990         if ((compat20 && type == MM_RSAHOSTKEY) ||
 991             (!compat20 && type != MM_RSAHOSTKEY))
 992                 fatal("%s: key type and protocol mismatch", __func__);
 993
 994         debug3("%s: key_from_blob: %p", __func__, key);
 995
 996         if (key != NULL && authctxt->valid) {
 997                 switch (type) {
 998                 case MM_USERKEY:
 999                         allowed = options.pubkey_authentication &&
1000                             user_key_allowed(authctxt->pw, key);
1001                         auth_method = "publickey";
1002                         break;
1003                 case MM_HOSTKEY:
1004                         allowed = options.hostbased_authentication &&
1005                             hostbased_key_allowed(authctxt->pw,
1006                             cuser, chost, key);
1007                         auth_method = "hostbased";
1008                         break;
1009                 case MM_RSAHOSTKEY:
1010                         key->type = KEY_RSA1; /* XXX */
1011                         allowed = options.rhosts_rsa_authentication &&
1012                             auth_rhosts_rsa_key_allowed(authctxt->pw,
1013                             cuser, chost, key);
1014                         auth_method = "rsa";
1015                         break;
1016                 default:
1017                         fatal("%s: unknown key type %d", __func__, type);
1018                         break;
1019                 }
1020         }
1021         if (key != NULL)
1022                 key_free(key);
1023
1024         /* clear temporarily storage (used by verify) */
1025         monitor_reset_key_state();
1026
1027         if (allowed) {
1028                 /* Save temporarily for comparison in verify */
1029                 key_blob = blob;
1030                 key_bloblen = bloblen;
1031                 key_blobtype = type;
1032                 hostbased_cuser = cuser;
1033                 hostbased_chost = chost;
1034         } else {
1035                 /* Log failed attempt */
1036                 auth_log(authctxt, 0, auth_method, compat20 ? " ssh2" : "");
1037                 xfree(blob);
1038                 xfree(cuser);
1039                 xfree(chost);
1040         }
1041
1042         debug3("%s: key %p is %s",
1043             __func__, key, allowed ? "allowed" : "disallowed");
1044
1045         buffer_clear(m);
1046         buffer_put_int(m, allowed);
1047         buffer_put_int(m, forced_command != NULL);
1048
1049         mm_append_debug(m);
1050
1051         mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m);
1052
1053         if (type == MM_RSAHOSTKEY)
1054                 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1055
1056         return (0);
1057 }
1058
1059 static int
1060 monitor_valid_userblob(u_char *data, u_int datalen)
1061 {
1062         Buffer b;
1063         char *p;
1064         u_int len;
1065         int fail = 0;
1066
1067         buffer_init(&b);
1068         buffer_append(&b, data, datalen);
1069
1070         if (datafellows & SSH_OLD_SESSIONID) {
1071                 p = buffer_ptr(&b);
1072                 len = buffer_len(&b);
1073                 if ((session_id2 == NULL) ||
1074                     (len < session_id2_len) ||
1075                     (memcmp(p, session_id2, session_id2_len) != 0))
1076                         fail++;
1077                 buffer_consume(&b, session_id2_len);
1078         } else {
1079                 p = buffer_get_string(&b, &len);
1080                 if ((session_id2 == NULL) ||
1081                     (len != session_id2_len) ||
1082                     (memcmp(p, session_id2, session_id2_len) != 0))
1083                         fail++;
1084                 xfree(p);
1085         }
1086         if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1087                 fail++;
1088         p = buffer_get_string(&b, NULL);
1089         if (strcmp(authctxt->user, p) != 0) {
1090                 logit("wrong user name passed to monitor: expected %s != %.100s",
1091                     authctxt->user, p);
1092                 fail++;
1093         }
1094         xfree(p);
1095         buffer_skip_string(&b);
1096         if (datafellows & SSH_BUG_PKAUTH) {
1097                 if (!buffer_get_char(&b))
1098                         fail++;
1099         } else {
1100                 p = buffer_get_string(&b, NULL);
1101                 if (strcmp("publickey", p) != 0)
1102                         fail++;
1103                 xfree(p);
1104                 if (!buffer_get_char(&b))
1105                         fail++;
1106                 buffer_skip_string(&b);
1107         }
1108         buffer_skip_string(&b);
1109         if (buffer_len(&b) != 0)
1110                 fail++;
1111         buffer_free(&b);
1112         return (fail == 0);
1113 }
1114
1115 static int
1116 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser,
1117     char *chost)
1118 {
1119         Buffer b;
1120         char *p;
1121         u_int len;
1122         int fail = 0;
1123
1124         buffer_init(&b);
1125         buffer_append(&b, data, datalen);
1126
1127         p = buffer_get_string(&b, &len);
1128         if ((session_id2 == NULL) ||
1129             (len != session_id2_len) ||
1130             (memcmp(p, session_id2, session_id2_len) != 0))
1131                 fail++;
1132         xfree(p);
1133
1134         if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1135                 fail++;
1136         p = buffer_get_string(&b, NULL);
1137         if (strcmp(authctxt->user, p) != 0) {
1138                 logit("wrong user name passed to monitor: expected %s != %.100s",
1139                     authctxt->user, p);
1140                 fail++;
1141         }
1142         xfree(p);
1143         buffer_skip_string(&b); /* service */
1144         p = buffer_get_string(&b, NULL);
1145         if (strcmp(p, "hostbased") != 0)
1146                 fail++;
1147         xfree(p);
1148         buffer_skip_string(&b); /* pkalg */
1149         buffer_skip_string(&b); /* pkblob */
1150
1151         /* verify client host, strip trailing dot if necessary */
1152         p = buffer_get_string(&b, NULL);
1153         if (((len = strlen(p)) > 0) && p[len - 1] == '.')
1154                 p[len - 1] = '\0';
1155         if (strcmp(p, chost) != 0)
1156                 fail++;
1157         xfree(p);
1158
1159         /* verify client user */
1160         p = buffer_get_string(&b, NULL);
1161         if (strcmp(p, cuser) != 0)
1162                 fail++;
1163         xfree(p);
1164
1165         if (buffer_len(&b) != 0)
1166                 fail++;
1167         buffer_free(&b);
1168         return (fail == 0);
1169 }
1170
1171 int
1172 mm_answer_keyverify(int sock, Buffer *m)
1173 {
1174         Key *key;
1175         u_char *signature, *data, *blob;
1176         u_int signaturelen, datalen, bloblen;
1177         int verified = 0;
1178         int valid_data = 0;
1179
1180         blob = buffer_get_string(m, &bloblen);
1181         signature = buffer_get_string(m, &signaturelen);
1182         data = buffer_get_string(m, &datalen);
1183
1184         if (hostbased_cuser == NULL || hostbased_chost == NULL ||
1185           !monitor_allowed_key(blob, bloblen))
1186                 fatal("%s: bad key, not previously allowed", __func__);
1187
1188         key = key_from_blob(blob, bloblen);
1189         if (key == NULL)
1190                 fatal("%s: bad public key blob", __func__);
1191
1192         switch (key_blobtype) {
1193         case MM_USERKEY:
1194                 valid_data = monitor_valid_userblob(data, datalen);
1195                 break;
1196         case MM_HOSTKEY:
1197                 valid_data = monitor_valid_hostbasedblob(data, datalen,
1198                     hostbased_cuser, hostbased_chost);
1199                 break;
1200         default:
1201                 valid_data = 0;
1202                 break;
1203         }
1204         if (!valid_data)
1205                 fatal("%s: bad signature data blob", __func__);
1206
1207         verified = key_verify(key, signature, signaturelen, data, datalen);
1208         debug3("%s: key %p signature %s",
1209             __func__, key, verified ? "verified" : "unverified");
1210
1211         key_free(key);
1212         xfree(blob);
1213         xfree(signature);
1214         xfree(data);
1215
1216         auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased";
1217
1218         monitor_reset_key_state();
1219
1220         buffer_clear(m);
1221         buffer_put_int(m, verified);
1222         mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m);
1223
1224         return (verified);
1225 }
1226
1227 static void
1228 mm_record_login(Session *s, struct passwd *pw)
1229 {
1230         socklen_t fromlen;
1231         struct sockaddr_storage from;
1232
1233         /*
1234          * Get IP address of client. If the connection is not a socket, let
1235          * the address be 0.0.0.0.
1236          */
1237         memset(&from, 0, sizeof(from));
1238         fromlen = sizeof(from);
1239         if (packet_connection_is_on_socket()) {
1240                 if (getpeername(packet_get_connection_in(),
1241                     (struct sockaddr *)&from, &fromlen) < 0) {
1242                         debug("getpeername: %.100s", strerror(errno));
1243                         cleanup_exit(255);
1244                 }
1245         }
1246         /* Record that there was a login on that tty from the remote host. */
1247         record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
1248             get_remote_name_or_ip(utmp_len, options.use_dns),
1249             (struct sockaddr *)&from, fromlen);
1250 }
1251
1252 static void
1253 mm_session_close(Session *s)
1254 {
1255         debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid);
1256         if (s->ttyfd != -1) {
1257                 debug3("%s: tty %s ptyfd %d",  __func__, s->tty, s->ptyfd);
1258                 session_pty_cleanup2(s);
1259         }
1260         s->used = 0;
1261 }
1262
1263 int
1264 mm_answer_pty(int sock, Buffer *m)
1265 {
1266         extern struct monitor *pmonitor;
1267         Session *s;
1268         int res, fd0;
1269
1270         debug3("%s entering", __func__);
1271
1272         buffer_clear(m);
1273         s = session_new();
1274         if (s == NULL)
1275                 goto error;
1276         s->authctxt = authctxt;
1277         s->pw = authctxt->pw;
1278         s->pid = pmonitor->m_pid;
1279         res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
1280         if (res == 0)
1281                 goto error;
1282         pty_setowner(authctxt->pw, s->tty);
1283
1284         buffer_put_int(m, 1);
1285         buffer_put_cstring(m, s->tty);
1286
1287         /* We need to trick ttyslot */
1288         if (dup2(s->ttyfd, 0) == -1)
1289                 fatal("%s: dup2", __func__);
1290
1291         mm_record_login(s, authctxt->pw);
1292
1293         /* Now we can close the file descriptor again */
1294         close(0);
1295
1296         /* send messages generated by record_login */
1297         buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
1298         buffer_clear(&loginmsg);
1299
1300         mm_request_send(sock, MONITOR_ANS_PTY, m);
1301
1302         mm_send_fd(sock, s->ptyfd);
1303         mm_send_fd(sock, s->ttyfd);
1304
1305         /* make sure nothing uses fd 0 */
1306         if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0)
1307                 fatal("%s: open(/dev/null): %s", __func__, strerror(errno));
1308         if (fd0 != 0)
1309                 error("%s: fd0 %d != 0", __func__, fd0);
1310
1311         /* slave is not needed */
1312         close(s->ttyfd);
1313         s->ttyfd = s->ptyfd;
1314         /* no need to dup() because nobody closes ptyfd */
1315         s->ptymaster = s->ptyfd;
1316
1317         debug3("%s: tty %s ptyfd %d",  __func__, s->tty, s->ttyfd);
1318
1319         return (0);
1320
1321  error:
1322         if (s != NULL)
1323                 mm_session_close(s);
1324         buffer_put_int(m, 0);
1325         mm_request_send(sock, MONITOR_ANS_PTY, m);
1326         return (0);
1327 }
1328
1329 int
1330 mm_answer_pty_cleanup(int sock, Buffer *m)
1331 {
1332         Session *s;
1333         char *tty;
1334
1335         debug3("%s entering", __func__);
1336
1337         tty = buffer_get_string(m, NULL);
1338         if ((s = session_by_tty(tty)) != NULL)
1339                 mm_session_close(s);
1340         buffer_clear(m);
1341         xfree(tty);
1342         return (0);
1343 }
1344
1345 int
1346 mm_answer_sesskey(int sock, Buffer *m)
1347 {
1348         BIGNUM *p;
1349         int rsafail;
1350
1351         /* Turn off permissions */
1352         monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0);
1353
1354         if ((p = BN_new()) == NULL)
1355                 fatal("%s: BN_new", __func__);
1356
1357         buffer_get_bignum2(m, p);
1358
1359         rsafail = ssh1_session_key(p);
1360
1361         buffer_clear(m);
1362         buffer_put_int(m, rsafail);
1363         buffer_put_bignum2(m, p);
1364
1365         BN_clear_free(p);
1366
1367         mm_request_send(sock, MONITOR_ANS_SESSKEY, m);
1368
1369         /* Turn on permissions for sessid passing */
1370         monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1);
1371
1372         return (0);
1373 }
1374
1375 int
1376 mm_answer_sessid(int sock, Buffer *m)
1377 {
1378         int i;
1379
1380         debug3("%s entering", __func__);
1381
1382         if (buffer_len(m) != 16)
1383                 fatal("%s: bad ssh1 session id", __func__);
1384         for (i = 0; i < 16; i++)
1385                 session_id[i] = buffer_get_char(m);
1386
1387         /* Turn on permissions for getpwnam */
1388         monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
1389
1390         return (0);
1391 }
1392
1393 int
1394 mm_answer_rsa_keyallowed(int sock, Buffer *m)
1395 {
1396         BIGNUM *client_n;
1397         Key *key = NULL;
1398         u_char *blob = NULL;
1399         u_int blen = 0;
1400         int allowed = 0;
1401
1402         debug3("%s entering", __func__);
1403
1404         auth_method = "rsa";
1405         if (options.rsa_authentication && authctxt->valid) {
1406                 if ((client_n = BN_new()) == NULL)
1407                         fatal("%s: BN_new", __func__);
1408                 buffer_get_bignum2(m, client_n);
1409                 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key);
1410                 BN_clear_free(client_n);
1411         }
1412         buffer_clear(m);
1413         buffer_put_int(m, allowed);
1414         buffer_put_int(m, forced_command != NULL);
1415
1416         /* clear temporarily storage (used by generate challenge) */
1417         monitor_reset_key_state();
1418
1419         if (allowed && key != NULL) {
1420                 key->type = KEY_RSA;    /* cheat for key_to_blob */
1421                 if (key_to_blob(key, &blob, &blen) == 0)
1422                         fatal("%s: key_to_blob failed", __func__);
1423                 buffer_put_string(m, blob, blen);
1424
1425                 /* Save temporarily for comparison in verify */
1426                 key_blob = blob;
1427                 key_bloblen = blen;
1428                 key_blobtype = MM_RSAUSERKEY;
1429         }
1430         if (key != NULL)
1431                 key_free(key);
1432
1433         mm_append_debug(m);
1434
1435         mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m);
1436
1437         monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1438         monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0);
1439         return (0);
1440 }
1441
1442 int
1443 mm_answer_rsa_challenge(int sock, Buffer *m)
1444 {
1445         Key *key = NULL;
1446         u_char *blob;
1447         u_int blen;
1448
1449         debug3("%s entering", __func__);
1450
1451         if (!authctxt->valid)
1452                 fatal("%s: authctxt not valid", __func__);
1453         blob = buffer_get_string(m, &blen);
1454         if (!monitor_allowed_key(blob, blen))
1455                 fatal("%s: bad key, not previously allowed", __func__);
1456         if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1457                 fatal("%s: key type mismatch", __func__);
1458         if ((key = key_from_blob(blob, blen)) == NULL)
1459                 fatal("%s: received bad key", __func__);
1460
1461         if (ssh1_challenge)
1462                 BN_clear_free(ssh1_challenge);
1463         ssh1_challenge = auth_rsa_generate_challenge(key);
1464
1465         buffer_clear(m);
1466         buffer_put_bignum2(m, ssh1_challenge);
1467
1468         debug3("%s sending reply", __func__);
1469         mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m);
1470
1471         monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1);
1472
1473         xfree(blob);
1474         key_free(key);
1475         return (0);
1476 }
1477
1478 int
1479 mm_answer_rsa_response(int sock, Buffer *m)
1480 {
1481         Key *key = NULL;
1482         u_char *blob, *response;
1483         u_int blen, len;
1484         int success;
1485
1486         debug3("%s entering", __func__);
1487
1488         if (!authctxt->valid)
1489                 fatal("%s: authctxt not valid", __func__);
1490         if (ssh1_challenge == NULL)
1491                 fatal("%s: no ssh1_challenge", __func__);
1492
1493         blob = buffer_get_string(m, &blen);
1494         if (!monitor_allowed_key(blob, blen))
1495                 fatal("%s: bad key, not previously allowed", __func__);
1496         if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1497                 fatal("%s: key type mismatch: %d", __func__, key_blobtype);
1498         if ((key = key_from_blob(blob, blen)) == NULL)
1499                 fatal("%s: received bad key", __func__);
1500         response = buffer_get_string(m, &len);
1501         if (len != 16)
1502                 fatal("%s: received bad response to challenge", __func__);
1503         success = auth_rsa_verify_response(key, ssh1_challenge, response);
1504
1505         xfree(blob);
1506         key_free(key);
1507         xfree(response);
1508
1509         auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa";
1510
1511         /* reset state */
1512         BN_clear_free(ssh1_challenge);
1513         ssh1_challenge = NULL;
1514         monitor_reset_key_state();
1515
1516         buffer_clear(m);
1517         buffer_put_int(m, success);
1518         mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m);
1519
1520         return (success);
1521 }
1522
1523 int
1524 mm_answer_term(int sock, Buffer *req)
1525 {
1526         extern struct monitor *pmonitor;
1527         int res, status;
1528
1529         debug3("%s: tearing down sessions", __func__);
1530
1531         /* The child is terminating */
1532         session_destroy_all(&mm_session_close);
1533
1534         while (waitpid(pmonitor->m_pid, &status, 0) == -1)
1535                 if (errno != EINTR)
1536                         exit(1);
1537
1538         res = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
1539
1540         /* Terminate process */
1541         exit(res);
1542 }
1543
1544 #ifdef SSH_AUDIT_EVENTS
1545 /* Report that an audit event occurred */
1546 int
1547 mm_answer_audit_event(int socket, Buffer *m)
1548 {
1549         ssh_audit_event_t event;
1550
1551         debug3("%s entering", __func__);
1552
1553         event = buffer_get_int(m);
1554         switch(event) {
1555         case SSH_AUTH_FAIL_PUBKEY:
1556         case SSH_AUTH_FAIL_HOSTBASED:
1557         case SSH_AUTH_FAIL_GSSAPI:
1558         case SSH_LOGIN_EXCEED_MAXTRIES:
1559         case SSH_LOGIN_ROOT_DENIED:
1560         case SSH_CONNECTION_CLOSE:
1561         case SSH_INVALID_USER:
1562                 audit_event(event);
1563                 break;
1564         default:
1565                 fatal("Audit event type %d not permitted", event);
1566         }
1567
1568         return (0);
1569 }
1570
1571 int
1572 mm_answer_audit_command(int socket, Buffer *m)
1573 {
1574         u_int len;
1575         char *cmd;
1576
1577         debug3("%s entering", __func__);
1578         cmd = buffer_get_string(m, &len);
1579         /* sanity check command, if so how? */
1580         audit_run_command(cmd);
1581         xfree(cmd);
1582         return (0);
1583 }
1584 #endif /* SSH_AUDIT_EVENTS */
1585
1586 void
1587 monitor_apply_keystate(struct monitor *pmonitor)
1588 {
1589         if (compat20) {
1590                 set_newkeys(MODE_IN);
1591                 set_newkeys(MODE_OUT);
1592         } else {
1593                 packet_set_protocol_flags(child_state.ssh1protoflags);
1594                 packet_set_encryption_key(child_state.ssh1key,
1595                     child_state.ssh1keylen, child_state.ssh1cipher);
1596                 xfree(child_state.ssh1key);
1597         }
1598
1599         /* for rc4 and other stateful ciphers */
1600         packet_set_keycontext(MODE_OUT, child_state.keyout);
1601         xfree(child_state.keyout);
1602         packet_set_keycontext(MODE_IN, child_state.keyin);
1603         xfree(child_state.keyin);
1604
1605         if (!compat20) {
1606                 packet_set_iv(MODE_OUT, child_state.ivout);
1607                 xfree(child_state.ivout);
1608                 packet_set_iv(MODE_IN, child_state.ivin);
1609                 xfree(child_state.ivin);
1610         }
1611
1612         memcpy(&incoming_stream, &child_state.incoming,
1613             sizeof(incoming_stream));
1614         memcpy(&outgoing_stream, &child_state.outgoing,
1615             sizeof(outgoing_stream));
1616
1617         /* Update with new address */
1618         if (options.compression)
1619                 mm_init_compression(pmonitor->m_zlib);
1620
1621         /* Network I/O buffers */
1622         /* XXX inefficient for large buffers, need: buffer_init_from_string */
1623         buffer_clear(&input);
1624         buffer_append(&input, child_state.input, child_state.ilen);
1625         memset(child_state.input, 0, child_state.ilen);
1626         xfree(child_state.input);
1627
1628         buffer_clear(&output);
1629         buffer_append(&output, child_state.output, child_state.olen);
1630         memset(child_state.output, 0, child_state.olen);
1631         xfree(child_state.output);
1632 }
1633
1634 static Kex *
1635 mm_get_kex(Buffer *m)
1636 {
1637         Kex *kex;
1638         void *blob;
1639         u_int bloblen;
1640
1641         kex = xcalloc(1, sizeof(*kex));
1642         kex->session_id = buffer_get_string(m, &kex->session_id_len);
1643         if ((session_id2 == NULL) ||
1644             (kex->session_id_len != session_id2_len) ||
1645             (memcmp(kex->session_id, session_id2, session_id2_len) != 0))
1646                 fatal("mm_get_get: internal error: bad session id");
1647         kex->we_need = buffer_get_int(m);
1648         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1649         kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1650         kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1651         kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1652         kex->server = 1;
1653         kex->hostkey_type = buffer_get_int(m);
1654         kex->kex_type = buffer_get_int(m);
1655         blob = buffer_get_string(m, &bloblen);
1656         buffer_init(&kex->my);
1657         buffer_append(&kex->my, blob, bloblen);
1658         xfree(blob);
1659         blob = buffer_get_string(m, &bloblen);
1660         buffer_init(&kex->peer);
1661         buffer_append(&kex->peer, blob, bloblen);
1662         xfree(blob);
1663         kex->done = 1;
1664         kex->flags = buffer_get_int(m);
1665         kex->client_version_string = buffer_get_string(m, NULL);
1666         kex->server_version_string = buffer_get_string(m, NULL);
1667         kex->load_host_key=&get_hostkey_by_type;
1668         kex->host_key_index=&get_hostkey_index;
1669
1670         return (kex);
1671 }
1672
1673 /* This function requries careful sanity checking */
1674
1675 void
1676 mm_get_keystate(struct monitor *pmonitor)
1677 {
1678         Buffer m;
1679         u_char *blob, *p;
1680         u_int bloblen, plen;
1681         u_int32_t seqnr, packets;
1682         u_int64_t blocks;
1683
1684         debug3("%s: Waiting for new keys", __func__);
1685
1686         buffer_init(&m);
1687         mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, &m);
1688         if (!compat20) {
1689                 child_state.ssh1protoflags = buffer_get_int(&m);
1690                 child_state.ssh1cipher = buffer_get_int(&m);
1691                 child_state.ssh1key = buffer_get_string(&m,
1692                     &child_state.ssh1keylen);
1693                 child_state.ivout = buffer_get_string(&m,
1694                     &child_state.ivoutlen);
1695                 child_state.ivin = buffer_get_string(&m, &child_state.ivinlen);
1696                 goto skip;
1697         } else {
1698                 /* Get the Kex for rekeying */
1699                 *pmonitor->m_pkex = mm_get_kex(&m);
1700         }
1701
1702         blob = buffer_get_string(&m, &bloblen);
1703         current_keys[MODE_OUT] = mm_newkeys_from_blob(blob, bloblen);
1704         xfree(blob);
1705
1706         debug3("%s: Waiting for second key", __func__);
1707         blob = buffer_get_string(&m, &bloblen);
1708         current_keys[MODE_IN] = mm_newkeys_from_blob(blob, bloblen);
1709         xfree(blob);
1710
1711         /* Now get sequence numbers for the packets */
1712         seqnr = buffer_get_int(&m);
1713         blocks = buffer_get_int64(&m);
1714         packets = buffer_get_int(&m);
1715         packet_set_state(MODE_OUT, seqnr, blocks, packets);
1716         seqnr = buffer_get_int(&m);
1717         blocks = buffer_get_int64(&m);
1718         packets = buffer_get_int(&m);
1719         packet_set_state(MODE_IN, seqnr, blocks, packets);
1720
1721  skip:
1722         /* Get the key context */
1723         child_state.keyout = buffer_get_string(&m, &child_state.keyoutlen);
1724         child_state.keyin  = buffer_get_string(&m, &child_state.keyinlen);
1725
1726         debug3("%s: Getting compression state", __func__);
1727         /* Get compression state */
1728         p = buffer_get_string(&m, &plen);
1729         if (plen != sizeof(child_state.outgoing))
1730                 fatal("%s: bad request size", __func__);
1731         memcpy(&child_state.outgoing, p, sizeof(child_state.outgoing));
1732         xfree(p);
1733
1734         p = buffer_get_string(&m, &plen);
1735         if (plen != sizeof(child_state.incoming))
1736                 fatal("%s: bad request size", __func__);
1737         memcpy(&child_state.incoming, p, sizeof(child_state.incoming));
1738         xfree(p);
1739
1740         /* Network I/O buffers */
1741         debug3("%s: Getting Network I/O buffers", __func__);
1742         child_state.input = buffer_get_string(&m, &child_state.ilen);
1743         child_state.output = buffer_get_string(&m, &child_state.olen);
1744
1745         buffer_free(&m);
1746 }
1747
1748
1749 /* Allocation functions for zlib */
1750 void *
1751 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size)
1752 {
1753         size_t len = (size_t) size * ncount;
1754         void *address;
1755
1756         if (len == 0 || ncount > SIZE_T_MAX / size)
1757                 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size);
1758
1759         address = mm_malloc(mm, len);
1760
1761         return (address);
1762 }
1763
1764 void
1765 mm_zfree(struct mm_master *mm, void *address)
1766 {
1767         mm_free(mm, address);
1768 }
1769
1770 void
1771 mm_init_compression(struct mm_master *mm)
1772 {
1773         outgoing_stream.zalloc = (alloc_func)mm_zalloc;
1774         outgoing_stream.zfree = (free_func)mm_zfree;
1775         outgoing_stream.opaque = mm;
1776
1777         incoming_stream.zalloc = (alloc_func)mm_zalloc;
1778         incoming_stream.zfree = (free_func)mm_zfree;
1779         incoming_stream.opaque = mm;
1780 }
1781
1782 /* XXX */
1783
1784 #define FD_CLOSEONEXEC(x) do { \
1785         if (fcntl(x, F_SETFD, 1) == -1) \
1786                 fatal("fcntl(%d, F_SETFD)", x); \
1787 } while (0)
1788
1789 static void
1790 monitor_socketpair(int *pair)
1791 {
1792 #ifdef HAVE_SOCKETPAIR
1793         if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
1794                 fatal("%s: socketpair", __func__);
1795 #else
1796         fatal("%s: UsePrivilegeSeparation=yes not supported",
1797             __func__);
1798 #endif
1799         FD_CLOSEONEXEC(pair[0]);
1800         FD_CLOSEONEXEC(pair[1]);
1801 }
1802
1803 #define MM_MEMSIZE      65536
1804
1805 struct monitor *
1806 monitor_init(void)
1807 {
1808         struct monitor *mon;
1809         int pair[2];
1810
1811         mon = xcalloc(1, sizeof(*mon));
1812
1813         monitor_socketpair(pair);
1814
1815         mon->m_recvfd = pair[0];
1816         mon->m_sendfd = pair[1];
1817
1818         /* Used to share zlib space across processes */
1819         if (options.compression) {
1820                 mon->m_zback = mm_create(NULL, MM_MEMSIZE);
1821                 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE);
1822
1823                 /* Compression needs to share state across borders */
1824                 mm_init_compression(mon->m_zlib);
1825         }
1826
1827         return mon;
1828 }
1829
1830 void
1831 monitor_reinit(struct monitor *mon)
1832 {
1833         int pair[2];
1834
1835         monitor_socketpair(pair);
1836
1837         mon->m_recvfd = pair[0];
1838         mon->m_sendfd = pair[1];
1839 }
1840
1841 #ifdef GSSAPI
1842 int
1843 mm_answer_gss_setup_ctx(int sock, Buffer *m)
1844 {
1845         gss_OID_desc goid;
1846         OM_uint32 major;
1847         u_int len;
1848
1849         goid.elements = buffer_get_string(m, &len);
1850         goid.length = len;
1851
1852         major = ssh_gssapi_server_ctx(&gsscontext, &goid);
1853
1854         xfree(goid.elements);
1855
1856         buffer_clear(m);
1857         buffer_put_int(m, major);
1858
1859         mm_request_send(sock, MONITOR_ANS_GSSSETUP, m);
1860
1861         /* Now we have a context, enable the step */
1862         monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1);
1863
1864         return (0);
1865 }
1866
1867 int
1868 mm_answer_gss_accept_ctx(int sock, Buffer *m)
1869 {
1870         gss_buffer_desc in;
1871         gss_buffer_desc out = GSS_C_EMPTY_BUFFER;
1872         OM_uint32 major, minor;
1873         OM_uint32 flags = 0; /* GSI needs this */
1874         u_int len;
1875
1876         in.value = buffer_get_string(m, &len);
1877         in.length = len;
1878         major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
1879         xfree(in.value);
1880
1881         buffer_clear(m);
1882         buffer_put_int(m, major);
1883         buffer_put_string(m, out.value, out.length);
1884         buffer_put_int(m, flags);
1885         mm_request_send(sock, MONITOR_ANS_GSSSTEP, m);
1886
1887         gss_release_buffer(&minor, &out);
1888
1889         if (major == GSS_S_COMPLETE) {
1890                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
1891                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1892                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
1893         }
1894         return (0);
1895 }
1896
1897 int
1898 mm_answer_gss_checkmic(int sock, Buffer *m)
1899 {
1900         gss_buffer_desc gssbuf, mic;
1901         OM_uint32 ret;
1902         u_int len;
1903
1904         gssbuf.value = buffer_get_string(m, &len);
1905         gssbuf.length = len;
1906         mic.value = buffer_get_string(m, &len);
1907         mic.length = len;
1908
1909         ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic);
1910
1911         xfree(gssbuf.value);
1912         xfree(mic.value);
1913
1914         buffer_clear(m);
1915         buffer_put_int(m, ret);
1916
1917         mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m);
1918
1919         if (!GSS_ERROR(ret))
1920                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1921
1922         return (0);
1923 }
1924
1925 int
1926 mm_answer_gss_userok(int sock, Buffer *m)
1927 {
1928         int authenticated;
1929
1930         authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
1931
1932         buffer_clear(m);
1933         buffer_put_int(m, authenticated);
1934
1935         debug3("%s: sending result %d", __func__, authenticated);
1936         mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
1937
1938         auth_method = "gssapi-with-mic";
1939
1940         /* Monitor loop will terminate if authenticated */
1941         return (authenticated);
1942 }
1943 #endif /* GSSAPI */