monitor.c

   1 /* $OpenBSD: monitor.c,v 1.82 2006/07/22 20:48:23 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 #include <string.h>
  42
  43 #ifdef SKEY
  44 #include <skey.h>
  45 #endif
  46
  47 #include <openssl/dh.h>
  48
  49 #include "ssh.h"
  50 #include "auth.h"
  51 #include "kex.h"
  52 #include "dh.h"
  53 #ifdef TARGET_OS_MAC    /* XXX Broken krb5 headers on Mac */
  54 #undef TARGET_OS_MAC
  55 #include "zlib.h"
  56 #define TARGET_OS_MAC 1
  57 #else
  58 #include "zlib.h"
  59 #endif
  60 #include "packet.h"
  61 #include "auth-options.h"
  62 #include "sshpty.h"
  63 #include "channels.h"
  64 #include "session.h"
  65 #include "sshlogin.h"
  66 #include "canohost.h"
  67 #include "log.h"
  68 #include "servconf.h"
  69 #include "monitor.h"
  70 #include "monitor_mm.h"
  71 #include "monitor_wrap.h"
  72 #include "monitor_fdpass.h"
  73 #include "xmalloc.h"
  74 #include "misc.h"
  75 #include "buffer.h"
  76 #include "bufaux.h"
  77 #include "compat.h"
  78 #include "ssh2.h"
  79
  80 #ifdef GSSAPI
  81 #include "ssh-gss.h"
  82 static Gssctxt *gsscontext = NULL;
  83 #endif
  84
  85 /* Imports */
  86 extern ServerOptions options;
  87 extern u_int utmp_len;
  88 extern Newkeys *current_keys[];
  89 extern z_stream incoming_stream;
  90 extern z_stream outgoing_stream;
  91 extern u_char session_id[];
  92 extern Buffer input, output;
  93 extern Buffer auth_debug;
  94 extern int auth_debug_init;
  95 extern Buffer loginmsg;
  96
  97 /* State exported from the child */
  98
  99 struct {
 100         z_stream incoming;
 101         z_stream outgoing;
 102         u_char *keyin;
 103         u_int keyinlen;
 104         u_char *keyout;
 105         u_int keyoutlen;
 106         u_char *ivin;
 107         u_int ivinlen;
 108         u_char *ivout;
 109         u_int ivoutlen;
 110         u_char *ssh1key;
 111         u_int ssh1keylen;
 112         int ssh1cipher;
 113         int ssh1protoflags;
 114         u_char *input;
 115         u_int ilen;
 116         u_char *output;
 117         u_int olen;
 118 } child_state;
 119
 120 /* Functions on the monitor that answer unprivileged requests */
 121
 122 int mm_answer_moduli(int, Buffer *);
 123 int mm_answer_sign(int, Buffer *);
 124 int mm_answer_pwnamallow(int, Buffer *);
 125 int mm_answer_auth2_read_banner(int, Buffer *);
 126 int mm_answer_authserv(int, Buffer *);
 127 int mm_answer_authpassword(int, Buffer *);
 128 int mm_answer_bsdauthquery(int, Buffer *);
 129 int mm_answer_bsdauthrespond(int, Buffer *);
 130 int mm_answer_skeyquery(int, Buffer *);
 131 int mm_answer_skeyrespond(int, Buffer *);
 132 int mm_answer_keyallowed(int, Buffer *);
 133 int mm_answer_keyverify(int, Buffer *);
 134 int mm_answer_pty(int, Buffer *);
 135 int mm_answer_pty_cleanup(int, Buffer *);
 136 int mm_answer_term(int, Buffer *);
 137 int mm_answer_rsa_keyallowed(int, Buffer *);
 138 int mm_answer_rsa_challenge(int, Buffer *);
 139 int mm_answer_rsa_response(int, Buffer *);
 140 int mm_answer_sesskey(int, Buffer *);
 141 int mm_answer_sessid(int, Buffer *);
 142
 143 #ifdef USE_PAM
 144 int mm_answer_pam_start(int, Buffer *);
 145 int mm_answer_pam_account(int, Buffer *);
 146 int mm_answer_pam_init_ctx(int, Buffer *);
 147 int mm_answer_pam_query(int, Buffer *);
 148 int mm_answer_pam_respond(int, Buffer *);
 149 int mm_answer_pam_free_ctx(int, Buffer *);
 150 #endif
 151
 152 #ifdef GSSAPI
 153 int mm_answer_gss_setup_ctx(int, Buffer *);
 154 int mm_answer_gss_accept_ctx(int, Buffer *);
 155 int mm_answer_gss_userok(int, Buffer *);
 156 int mm_answer_gss_checkmic(int, Buffer *);
 157 #endif
 158
 159 #ifdef SSH_AUDIT_EVENTS
 160 int mm_answer_audit_event(int, Buffer *);
 161 int mm_answer_audit_command(int, Buffer *);
 162 #endif
 163
 164 static Authctxt *authctxt;
 165 static BIGNUM *ssh1_challenge = NULL;   /* used for ssh1 rsa auth */
 166
 167 /* local state for key verify */
 168 static u_char *key_blob = NULL;
 169 static u_int key_bloblen = 0;
 170 static int key_blobtype = MM_NOKEY;
 171 static char *hostbased_cuser = NULL;
 172 static char *hostbased_chost = NULL;
 173 static char *auth_method = "unknown";
 174 static u_int session_id2_len = 0;
 175 static u_char *session_id2 = NULL;
 176 static pid_t monitor_child_pid;
 177
 178 struct mon_table {
 179         enum monitor_reqtype type;
 180         int flags;
 181         int (*f)(int, Buffer *);
 182 };
 183
 184 #define MON_ISAUTH      0x0004  /* Required for Authentication */
 185 #define MON_AUTHDECIDE  0x0008  /* Decides Authentication */
 186 #define MON_ONCE        0x0010  /* Disable after calling */
 187 #define MON_ALOG        0x0020  /* Log auth attempt without authenticating */
 188
 189 #define MON_AUTH        (MON_ISAUTH|MON_AUTHDECIDE)
 190
 191 #define MON_PERMIT      0x1000  /* Request is permitted */
 192
 193 struct mon_table mon_dispatch_proto20[] = {
 194     {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli},
 195     {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
 196     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
 197     {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
 198     {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
 199     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 200 #ifdef USE_PAM
 201     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
 202     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
 203     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
 204     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
 205     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
 206     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 207 #endif
 208 #ifdef SSH_AUDIT_EVENTS
 209     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 210 #endif
 211 #ifdef BSD_AUTH
 212     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
 213     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
 214 #endif
 215 #ifdef SKEY
 216     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
 217     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
 218 #endif
 219     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
 220     {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
 221 #ifdef GSSAPI
 222     {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx},
 223     {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx},
 224     {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok},
 225     {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic},
 226 #endif
 227     {0, 0, NULL}
 228 };
 229
 230 struct mon_table mon_dispatch_postauth20[] = {
 231     {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
 232     {MONITOR_REQ_SIGN, 0, mm_answer_sign},
 233     {MONITOR_REQ_PTY, 0, mm_answer_pty},
 234     {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
 235     {MONITOR_REQ_TERM, 0, mm_answer_term},
 236 #ifdef SSH_AUDIT_EVENTS
 237     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 238     {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
 239 #endif
 240     {0, 0, NULL}
 241 };
 242
 243 struct mon_table mon_dispatch_proto15[] = {
 244     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
 245     {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey},
 246     {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid},
 247     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 248     {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_rsa_keyallowed},
 249     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_keyallowed},
 250     {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge},
 251     {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response},
 252 #ifdef BSD_AUTH
 253     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
 254     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
 255 #endif
 256 #ifdef SKEY
 257     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
 258     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
 259 #endif
 260 #ifdef USE_PAM
 261     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
 262     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
 263     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
 264     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
 265     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
 266     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 267 #endif
 268 #ifdef SSH_AUDIT_EVENTS
 269     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 270 #endif
 271     {0, 0, NULL}
 272 };
 273
 274 struct mon_table mon_dispatch_postauth15[] = {
 275     {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty},
 276     {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup},
 277     {MONITOR_REQ_TERM, 0, mm_answer_term},
 278 #ifdef SSH_AUDIT_EVENTS
 279     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
 280     {MONITOR_REQ_AUDIT_COMMAND, MON_ONCE, mm_answer_audit_command},
 281 #endif
 282     {0, 0, NULL}
 283 };
 284
 285 struct mon_table *mon_dispatch;
 286
 287 /* Specifies if a certain message is allowed at the moment */
 288
 289 static void
 290 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit)
 291 {
 292         while (ent->f != NULL) {
 293                 if (ent->type == type) {
 294                         ent->flags &= ~MON_PERMIT;
 295                         ent->flags |= permit ? MON_PERMIT : 0;
 296                         return;
 297                 }
 298                 ent++;
 299         }
 300 }
 301
 302 static void
 303 monitor_permit_authentications(int permit)
 304 {
 305         struct mon_table *ent = mon_dispatch;
 306
 307         while (ent->f != NULL) {
 308                 if (ent->flags & MON_AUTH) {
 309                         ent->flags &= ~MON_PERMIT;
 310                         ent->flags |= permit ? MON_PERMIT : 0;
 311                 }
 312                 ent++;
 313         }
 314 }
 315
 316 void
 317 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
 318 {
 319         struct mon_table *ent;
 320         int authenticated = 0;
 321
 322         debug3("preauth child monitor started");
 323
 324         authctxt = _authctxt;
 325         memset(authctxt, 0, sizeof(*authctxt));
 326
 327         authctxt->loginmsg = &loginmsg;
 328
 329         if (compat20) {
 330                 mon_dispatch = mon_dispatch_proto20;
 331
 332                 /* Permit requests for moduli and signatures */
 333                 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 334                 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 335         } else {
 336                 mon_dispatch = mon_dispatch_proto15;
 337
 338                 monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1);
 339         }
 340
 341         /* The first few requests do not require asynchronous access */
 342         while (!authenticated) {
 343                 auth_method = "unknown";
 344                 authenticated = monitor_read(pmonitor, mon_dispatch, &ent);
 345                 if (authenticated) {
 346                         if (!(ent->flags & MON_AUTHDECIDE))
 347                                 fatal("%s: unexpected authentication from %d",
 348                                     __func__, ent->type);
 349                         if (authctxt->pw->pw_uid == 0 &&
 350                             !auth_root_allowed(auth_method))
 351                                 authenticated = 0;
 352 #ifdef USE_PAM
 353                         /* PAM needs to perform account checks after auth */
 354                         if (options.use_pam && authenticated) {
 355                                 Buffer m;
 356
 357                                 buffer_init(&m);
 358                                 mm_request_receive_expect(pmonitor->m_sendfd,
 359                                     MONITOR_REQ_PAM_ACCOUNT, &m);
 360                                 authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m);
 361                                 buffer_free(&m);
 362                         }
 363 #endif
 364                 }
 365
 366                 if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
 367                         auth_log(authctxt, authenticated, auth_method,
 368                             compat20 ? " ssh2" : "");
 369                         if (!authenticated)
 370                                 authctxt->failures++;
 371                 }
 372         }
 373
 374         if (!authctxt->valid)
 375                 fatal("%s: authenticated invalid user", __func__);
 376         if (strcmp(auth_method, "unknown") == 0)
 377                 fatal("%s: authentication method name unknown", __func__);
 378
 379         debug("%s: %s has been authenticated by privileged process",
 380             __func__, authctxt->user);
 381
 382         mm_get_keystate(pmonitor);
 383 }
 384
 385 static void
 386 monitor_set_child_handler(pid_t pid)
 387 {
 388         monitor_child_pid = pid;
 389 }
 390
 391 static void
 392 monitor_child_handler(int sig)
 393 {
 394         kill(monitor_child_pid, sig);
 395 }
 396
 397 void
 398 monitor_child_postauth(struct monitor *pmonitor)
 399 {
 400         monitor_set_child_handler(pmonitor->m_pid);
 401         signal(SIGHUP, &monitor_child_handler);
 402         signal(SIGTERM, &monitor_child_handler);
 403
 404         if (compat20) {
 405                 mon_dispatch = mon_dispatch_postauth20;
 406
 407                 /* Permit requests for moduli and signatures */
 408                 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
 409                 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
 410                 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
 411         } else {
 412                 mon_dispatch = mon_dispatch_postauth15;
 413                 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
 414         }
 415         if (!no_pty_flag) {
 416                 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
 417                 monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1);
 418         }
 419
 420         for (;;)
 421                 monitor_read(pmonitor, mon_dispatch, NULL);
 422 }
 423
 424 void
 425 monitor_sync(struct monitor *pmonitor)
 426 {
 427         if (options.compression) {
 428                 /* The member allocation is not visible, so sync it */
 429                 mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback);
 430         }
 431 }
 432
 433 int
 434 monitor_read(struct monitor *pmonitor, struct mon_table *ent,
 435     struct mon_table **pent)
 436 {
 437         Buffer m;
 438         int ret;
 439         u_char type;
 440
 441         buffer_init(&m);
 442
 443         mm_request_receive(pmonitor->m_sendfd, &m);
 444         type = buffer_get_char(&m);
 445
 446         debug3("%s: checking request %d", __func__, type);
 447
 448         while (ent->f != NULL) {
 449                 if (ent->type == type)
 450                         break;
 451                 ent++;
 452         }
 453
 454         if (ent->f != NULL) {
 455                 if (!(ent->flags & MON_PERMIT))
 456                         fatal("%s: unpermitted request %d", __func__,
 457                             type);
 458                 ret = (*ent->f)(pmonitor->m_sendfd, &m);
 459                 buffer_free(&m);
 460
 461                 /* The child may use this request only once, disable it */
 462                 if (ent->flags & MON_ONCE) {
 463                         debug2("%s: %d used once, disabling now", __func__,
 464                             type);
 465                         ent->flags &= ~MON_PERMIT;
 466                 }
 467
 468                 if (pent != NULL)
 469                         *pent = ent;
 470
 471                 return ret;
 472         }
 473
 474         fatal("%s: unsupported request: %d", __func__, type);
 475
 476         /* NOTREACHED */
 477         return (-1);
 478 }
 479
 480 /* allowed key state */
 481 static int
 482 monitor_allowed_key(u_char *blob, u_int bloblen)
 483 {
 484         /* make sure key is allowed */
 485         if (key_blob == NULL || key_bloblen != bloblen ||
 486             memcmp(key_blob, blob, key_bloblen))
 487                 return (0);
 488         return (1);
 489 }
 490
 491 static void
 492 monitor_reset_key_state(void)
 493 {
 494         /* reset state */
 495         if (key_blob != NULL)
 496                 xfree(key_blob);
 497         if (hostbased_cuser != NULL)
 498                 xfree(hostbased_cuser);
 499         if (hostbased_chost != NULL)
 500                 xfree(hostbased_chost);
 501         key_blob = NULL;
 502         key_bloblen = 0;
 503         key_blobtype = MM_NOKEY;
 504         hostbased_cuser = NULL;
 505         hostbased_chost = NULL;
 506 }
 507
 508 int
 509 mm_answer_moduli(int sock, Buffer *m)
 510 {
 511         DH *dh;
 512         int min, want, max;
 513
 514         min = buffer_get_int(m);
 515         want = buffer_get_int(m);
 516         max = buffer_get_int(m);
 517
 518         debug3("%s: got parameters: %d %d %d",
 519             __func__, min, want, max);
 520         /* We need to check here, too, in case the child got corrupted */
 521         if (max < min || want < min || max < want)
 522                 fatal("%s: bad parameters: %d %d %d",
 523                     __func__, min, want, max);
 524
 525         buffer_clear(m);
 526
 527         dh = choose_dh(min, want, max);
 528         if (dh == NULL) {
 529                 buffer_put_char(m, 0);
 530                 return (0);
 531         } else {
 532                 /* Send first bignum */
 533                 buffer_put_char(m, 1);
 534                 buffer_put_bignum2(m, dh->p);
 535                 buffer_put_bignum2(m, dh->g);
 536
 537                 DH_free(dh);
 538         }
 539         mm_request_send(sock, MONITOR_ANS_MODULI, m);
 540         return (0);
 541 }
 542
 543 int
 544 mm_answer_sign(int sock, Buffer *m)
 545 {
 546         Key *key;
 547         u_char *p;
 548         u_char *signature;
 549         u_int siglen, datlen;
 550         int keyid;
 551
 552         debug3("%s", __func__);
 553
 554         keyid = buffer_get_int(m);
 555         p = buffer_get_string(m, &datlen);
 556
 557         /*
 558          * Supported KEX types will only return SHA1 (20 byte) or
 559          * SHA256 (32 byte) hashes
 560          */
 561         if (datlen != 20 && datlen != 32)
 562                 fatal("%s: data length incorrect: %u", __func__, datlen);
 563
 564         /* save session id, it will be passed on the first call */
 565         if (session_id2_len == 0) {
 566                 session_id2_len = datlen;
 567                 session_id2 = xmalloc(session_id2_len);
 568                 memcpy(session_id2, p, session_id2_len);
 569         }
 570
 571         if ((key = get_hostkey_by_index(keyid)) == NULL)
 572                 fatal("%s: no hostkey from index %d", __func__, keyid);
 573         if (key_sign(key, &signature, &siglen, p, datlen) < 0)
 574                 fatal("%s: key_sign failed", __func__);
 575
 576         debug3("%s: signature %p(%u)", __func__, signature, siglen);
 577
 578         buffer_clear(m);
 579         buffer_put_string(m, signature, siglen);
 580
 581         xfree(p);
 582         xfree(signature);
 583
 584         mm_request_send(sock, MONITOR_ANS_SIGN, m);
 585
 586         /* Turn on permissions for getpwnam */
 587         monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
 588
 589         return (0);
 590 }
 591
 592 /* Retrieves the password entry and also checks if the user is permitted */
 593
 594 int
 595 mm_answer_pwnamallow(int sock, Buffer *m)
 596 {
 597         char *username;
 598         struct passwd *pwent;
 599         int allowed = 0;
 600
 601         debug3("%s", __func__);
 602
 603         if (authctxt->attempt++ != 0)
 604                 fatal("%s: multiple attempts for getpwnam", __func__);
 605
 606         username = buffer_get_string(m, NULL);
 607
 608         pwent = getpwnamallow(username);
 609
 610         authctxt->user = xstrdup(username);
 611         setproctitle("%s [priv]", pwent ? username : "unknown");
 612         xfree(username);
 613
 614         buffer_clear(m);
 615
 616         if (pwent == NULL) {
 617                 buffer_put_char(m, 0);
 618                 authctxt->pw = fakepw();
 619                 goto out;
 620         }
 621
 622         allowed = 1;
 623         authctxt->pw = pwent;
 624         authctxt->valid = 1;
 625
 626         buffer_put_char(m, 1);
 627         buffer_put_string(m, pwent, sizeof(struct passwd));
 628         buffer_put_cstring(m, pwent->pw_name);
 629         buffer_put_cstring(m, "*");
 630         buffer_put_cstring(m, pwent->pw_gecos);
 631 #ifdef HAVE_PW_CLASS_IN_PASSWD
 632         buffer_put_cstring(m, pwent->pw_class);
 633 #endif
 634         buffer_put_cstring(m, pwent->pw_dir);
 635         buffer_put_cstring(m, pwent->pw_shell);
 636
 637  out:
 638         debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed);
 639         mm_request_send(sock, MONITOR_ANS_PWNAM, m);
 640
 641         /* For SSHv1 allow authentication now */
 642         if (!compat20)
 643                 monitor_permit_authentications(1);
 644         else {
 645                 /* Allow service/style information on the auth context */
 646                 monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
 647                 monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
 648         }
 649
 650 #ifdef USE_PAM
 651         if (options.use_pam)
 652                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
 653 #endif
 654 #ifdef SSH_AUDIT_EVENTS
 655         monitor_permit(mon_dispatch, MONITOR_REQ_AUDIT_COMMAND, 1);
 656 #endif
 657
 658         return (0);
 659 }
 660
 661 int mm_answer_auth2_read_banner(int sock, Buffer *m)
 662 {
 663         char *banner;
 664
 665         buffer_clear(m);
 666         banner = auth2_read_banner();
 667         buffer_put_cstring(m, banner != NULL ? banner : "");
 668         mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m);
 669
 670         if (banner != NULL)
 671                 xfree(banner);
 672
 673         return (0);
 674 }
 675
 676 int
 677 mm_answer_authserv(int sock, Buffer *m)
 678 {
 679         monitor_permit_authentications(1);
 680
 681         authctxt->service = buffer_get_string(m, NULL);
 682         authctxt->style = buffer_get_string(m, NULL);
 683         debug3("%s: service=%s, style=%s",
 684             __func__, authctxt->service, authctxt->style);
 685
 686         if (strlen(authctxt->style) == 0) {
 687                 xfree(authctxt->style);
 688                 authctxt->style = NULL;
 689         }
 690
 691         return (0);
 692 }
 693
 694 int
 695 mm_answer_authpassword(int sock, Buffer *m)
 696 {
 697         static int call_count;
 698         char *passwd;
 699         int authenticated;
 700         u_int plen;
 701
 702         passwd = buffer_get_string(m, &plen);
 703         /* Only authenticate if the context is valid */
 704         authenticated = options.password_authentication &&
 705             auth_password(authctxt, passwd);
 706         memset(passwd, 0, strlen(passwd));
 707         xfree(passwd);
 708
 709         buffer_clear(m);
 710         buffer_put_int(m, authenticated);
 711
 712         debug3("%s: sending result %d", __func__, authenticated);
 713         mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m);
 714
 715         call_count++;
 716         if (plen == 0 && call_count == 1)
 717                 auth_method = "none";
 718         else
 719                 auth_method = "password";
 720
 721         /* Causes monitor loop to terminate if authenticated */
 722         return (authenticated);
 723 }
 724
 725 #ifdef BSD_AUTH
 726 int
 727 mm_answer_bsdauthquery(int sock, Buffer *m)
 728 {
 729         char *name, *infotxt;
 730         u_int numprompts;
 731         u_int *echo_on;
 732         char **prompts;
 733         u_int success;
 734
 735         success = bsdauth_query(authctxt, &name, &infotxt, &numprompts,
 736             &prompts, &echo_on) < 0 ? 0 : 1;
 737
 738         buffer_clear(m);
 739         buffer_put_int(m, success);
 740         if (success)
 741                 buffer_put_cstring(m, prompts[0]);
 742
 743         debug3("%s: sending challenge success: %u", __func__, success);
 744         mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m);
 745
 746         if (success) {
 747                 xfree(name);
 748                 xfree(infotxt);
 749                 xfree(prompts);
 750                 xfree(echo_on);
 751         }
 752
 753         return (0);
 754 }
 755
 756 int
 757 mm_answer_bsdauthrespond(int sock, Buffer *m)
 758 {
 759         char *response;
 760         int authok;
 761
 762         if (authctxt->as == 0)
 763                 fatal("%s: no bsd auth session", __func__);
 764
 765         response = buffer_get_string(m, NULL);
 766         authok = options.challenge_response_authentication &&
 767             auth_userresponse(authctxt->as, response, 0);
 768         authctxt->as = NULL;
 769         debug3("%s: <%s> = <%d>", __func__, response, authok);
 770         xfree(response);
 771
 772         buffer_clear(m);
 773         buffer_put_int(m, authok);
 774
 775         debug3("%s: sending authenticated: %d", __func__, authok);
 776         mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
 777
 778         auth_method = "bsdauth";
 779
 780         return (authok != 0);
 781 }
 782 #endif
 783
 784 #ifdef SKEY
 785 int
 786 mm_answer_skeyquery(int sock, Buffer *m)
 787 {
 788         struct skey skey;
 789         char challenge[1024];
 790         u_int success;
 791
 792         success = _compat_skeychallenge(&skey, authctxt->user, challenge,
 793             sizeof(challenge)) < 0 ? 0 : 1;
 794
 795         buffer_clear(m);
 796         buffer_put_int(m, success);
 797         if (success)
 798                 buffer_put_cstring(m, challenge);
 799
 800         debug3("%s: sending challenge success: %u", __func__, success);
 801         mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m);
 802
 803         return (0);
 804 }
 805
 806 int
 807 mm_answer_skeyrespond(int sock, Buffer *m)
 808 {
 809         char *response;
 810         int authok;
 811
 812         response = buffer_get_string(m, NULL);
 813
 814         authok = (options.challenge_response_authentication &&
 815             authctxt->valid &&
 816             skey_haskey(authctxt->pw->pw_name) == 0 &&
 817             skey_passcheck(authctxt->pw->pw_name, response) != -1);
 818
 819         xfree(response);
 820
 821         buffer_clear(m);
 822         buffer_put_int(m, authok);
 823
 824         debug3("%s: sending authenticated: %d", __func__, authok);
 825         mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m);
 826
 827         auth_method = "skey";
 828
 829         return (authok != 0);
 830 }
 831 #endif
 832
 833 #ifdef USE_PAM
 834 int
 835 mm_answer_pam_start(int sock, Buffer *m)
 836 {
 837         if (!options.use_pam)
 838                 fatal("UsePAM not set, but ended up in %s anyway", __func__);
 839
 840         start_pam(authctxt);
 841
 842         monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1);
 843
 844         return (0);
 845 }
 846
 847 int
 848 mm_answer_pam_account(int sock, Buffer *m)
 849 {
 850         u_int ret;
 851
 852         if (!options.use_pam)
 853                 fatal("UsePAM not set, but ended up in %s anyway", __func__);
 854
 855         ret = do_pam_account();
 856
 857         buffer_put_int(m, ret);
 858         buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
 859
 860         mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m);
 861
 862         return (ret);
 863 }
 864
 865 static void *sshpam_ctxt, *sshpam_authok;
 866 extern KbdintDevice sshpam_device;
 867
 868 int
 869 mm_answer_pam_init_ctx(int sock, Buffer *m)
 870 {
 871
 872         debug3("%s", __func__);
 873         authctxt->user = buffer_get_string(m, NULL);
 874         sshpam_ctxt = (sshpam_device.init_ctx)(authctxt);
 875         sshpam_authok = NULL;
 876         buffer_clear(m);
 877         if (sshpam_ctxt != NULL) {
 878                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
 879                 buffer_put_int(m, 1);
 880         } else {
 881                 buffer_put_int(m, 0);
 882         }
 883         mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m);
 884         return (0);
 885 }
 886
 887 int
 888 mm_answer_pam_query(int sock, Buffer *m)
 889 {
 890         char *name, *info, **prompts;
 891         u_int i, num, *echo_on;
 892         int ret;
 893
 894         debug3("%s", __func__);
 895         sshpam_authok = NULL;
 896         ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, &num, &prompts, &echo_on);
 897         if (ret == 0 && num == 0)
 898                 sshpam_authok = sshpam_ctxt;
 899         if (num > 1 || name == NULL || info == NULL)
 900                 ret = -1;
 901         buffer_clear(m);
 902         buffer_put_int(m, ret);
 903         buffer_put_cstring(m, name);
 904         xfree(name);
 905         buffer_put_cstring(m, info);
 906         xfree(info);
 907         buffer_put_int(m, num);
 908         for (i = 0; i < num; ++i) {
 909                 buffer_put_cstring(m, prompts[i]);
 910                 xfree(prompts[i]);
 911                 buffer_put_int(m, echo_on[i]);
 912         }
 913         if (prompts != NULL)
 914                 xfree(prompts);
 915         if (echo_on != NULL)
 916                 xfree(echo_on);
 917         auth_method = "keyboard-interactive/pam";
 918         mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m);
 919         return (0);
 920 }
 921
 922 int
 923 mm_answer_pam_respond(int sock, Buffer *m)
 924 {
 925         char **resp;
 926         u_int i, num;
 927         int ret;
 928
 929         debug3("%s", __func__);
 930         sshpam_authok = NULL;
 931         num = buffer_get_int(m);
 932         if (num > 0) {
 933                 resp = xcalloc(num, sizeof(char *));
 934                 for (i = 0; i < num; ++i)
 935                         resp[i] = buffer_get_string(m, NULL);
 936                 ret = (sshpam_device.respond)(sshpam_ctxt, num, resp);
 937                 for (i = 0; i < num; ++i)
 938                         xfree(resp[i]);
 939                 xfree(resp);
 940         } else {
 941                 ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL);
 942         }
 943         buffer_clear(m);
 944         buffer_put_int(m, ret);
 945         mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m);
 946         auth_method = "keyboard-interactive/pam";
 947         if (ret == 0)
 948                 sshpam_authok = sshpam_ctxt;
 949         return (0);
 950 }
 951
 952 int
 953 mm_answer_pam_free_ctx(int sock, Buffer *m)
 954 {
 955
 956         debug3("%s", __func__);
 957         (sshpam_device.free_ctx)(sshpam_ctxt);
 958         buffer_clear(m);
 959         mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m);
 960         auth_method = "keyboard-interactive/pam";
 961         return (sshpam_authok == sshpam_ctxt);
 962 }
 963 #endif
 964
 965 static void
 966 mm_append_debug(Buffer *m)
 967 {
 968         if (auth_debug_init && buffer_len(&auth_debug)) {
 969                 debug3("%s: Appending debug messages for child", __func__);
 970                 buffer_append(m, buffer_ptr(&auth_debug),
 971                     buffer_len(&auth_debug));
 972                 buffer_clear(&auth_debug);
 973         }
 974 }
 975
 976 int
 977 mm_answer_keyallowed(int sock, Buffer *m)
 978 {
 979         Key *key;
 980         char *cuser, *chost;
 981         u_char *blob;
 982         u_int bloblen;
 983         enum mm_keytype type = 0;
 984         int allowed = 0;
 985
 986         debug3("%s entering", __func__);
 987
 988         type = buffer_get_int(m);
 989         cuser = buffer_get_string(m, NULL);
 990         chost = buffer_get_string(m, NULL);
 991         blob = buffer_get_string(m, &bloblen);
 992
 993         key = key_from_blob(blob, bloblen);
 994
 995         if ((compat20 && type == MM_RSAHOSTKEY) ||
 996             (!compat20 && type != MM_RSAHOSTKEY))
 997                 fatal("%s: key type and protocol mismatch", __func__);
 998
 999         debug3("%s: key_from_blob: %p", __func__, key);
1000
1001         if (key != NULL && authctxt->valid) {
1002                 switch (type) {
1003                 case MM_USERKEY:
1004                         allowed = options.pubkey_authentication &&
1005                             user_key_allowed(authctxt->pw, key);
1006                         auth_method = "publickey";
1007                         break;
1008                 case MM_HOSTKEY:
1009                         allowed = options.hostbased_authentication &&
1010                             hostbased_key_allowed(authctxt->pw,
1011                             cuser, chost, key);
1012                         auth_method = "hostbased";
1013                         break;
1014                 case MM_RSAHOSTKEY:
1015                         key->type = KEY_RSA1; /* XXX */
1016                         allowed = options.rhosts_rsa_authentication &&
1017                             auth_rhosts_rsa_key_allowed(authctxt->pw,
1018                             cuser, chost, key);
1019                         auth_method = "rsa";
1020                         break;
1021                 default:
1022                         fatal("%s: unknown key type %d", __func__, type);
1023                         break;
1024                 }
1025         }
1026         if (key != NULL)
1027                 key_free(key);
1028
1029         /* clear temporarily storage (used by verify) */
1030         monitor_reset_key_state();
1031
1032         if (allowed) {
1033                 /* Save temporarily for comparison in verify */
1034                 key_blob = blob;
1035                 key_bloblen = bloblen;
1036                 key_blobtype = type;
1037                 hostbased_cuser = cuser;
1038                 hostbased_chost = chost;
1039         } else {
1040                 /* Log failed attempt */
1041                 auth_log(authctxt, 0, auth_method, compat20 ? " ssh2" : "");
1042                 xfree(blob);
1043                 xfree(cuser);
1044                 xfree(chost);
1045         }
1046
1047         debug3("%s: key %p is %s",
1048             __func__, key, allowed ? "allowed" : "disallowed");
1049
1050         buffer_clear(m);
1051         buffer_put_int(m, allowed);
1052         buffer_put_int(m, forced_command != NULL);
1053
1054         mm_append_debug(m);
1055
1056         mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m);
1057
1058         if (type == MM_RSAHOSTKEY)
1059                 monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1060
1061         return (0);
1062 }
1063
1064 static int
1065 monitor_valid_userblob(u_char *data, u_int datalen)
1066 {
1067         Buffer b;
1068         char *p;
1069         u_int len;
1070         int fail = 0;
1071
1072         buffer_init(&b);
1073         buffer_append(&b, data, datalen);
1074
1075         if (datafellows & SSH_OLD_SESSIONID) {
1076                 p = buffer_ptr(&b);
1077                 len = buffer_len(&b);
1078                 if ((session_id2 == NULL) ||
1079                     (len < session_id2_len) ||
1080                     (memcmp(p, session_id2, session_id2_len) != 0))
1081                         fail++;
1082                 buffer_consume(&b, session_id2_len);
1083         } else {
1084                 p = buffer_get_string(&b, &len);
1085                 if ((session_id2 == NULL) ||
1086                     (len != session_id2_len) ||
1087                     (memcmp(p, session_id2, session_id2_len) != 0))
1088                         fail++;
1089                 xfree(p);
1090         }
1091         if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1092                 fail++;
1093         p = buffer_get_string(&b, NULL);
1094         if (strcmp(authctxt->user, p) != 0) {
1095                 logit("wrong user name passed to monitor: expected %s != %.100s",
1096                     authctxt->user, p);
1097                 fail++;
1098         }
1099         xfree(p);
1100         buffer_skip_string(&b);
1101         if (datafellows & SSH_BUG_PKAUTH) {
1102                 if (!buffer_get_char(&b))
1103                         fail++;
1104         } else {
1105                 p = buffer_get_string(&b, NULL);
1106                 if (strcmp("publickey", p) != 0)
1107                         fail++;
1108                 xfree(p);
1109                 if (!buffer_get_char(&b))
1110                         fail++;
1111                 buffer_skip_string(&b);
1112         }
1113         buffer_skip_string(&b);
1114         if (buffer_len(&b) != 0)
1115                 fail++;
1116         buffer_free(&b);
1117         return (fail == 0);
1118 }
1119
1120 static int
1121 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser,
1122     char *chost)
1123 {
1124         Buffer b;
1125         char *p;
1126         u_int len;
1127         int fail = 0;
1128
1129         buffer_init(&b);
1130         buffer_append(&b, data, datalen);
1131
1132         p = buffer_get_string(&b, &len);
1133         if ((session_id2 == NULL) ||
1134             (len != session_id2_len) ||
1135             (memcmp(p, session_id2, session_id2_len) != 0))
1136                 fail++;
1137         xfree(p);
1138
1139         if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1140                 fail++;
1141         p = buffer_get_string(&b, NULL);
1142         if (strcmp(authctxt->user, p) != 0) {
1143                 logit("wrong user name passed to monitor: expected %s != %.100s",
1144                     authctxt->user, p);
1145                 fail++;
1146         }
1147         xfree(p);
1148         buffer_skip_string(&b); /* service */
1149         p = buffer_get_string(&b, NULL);
1150         if (strcmp(p, "hostbased") != 0)
1151                 fail++;
1152         xfree(p);
1153         buffer_skip_string(&b); /* pkalg */
1154         buffer_skip_string(&b); /* pkblob */
1155
1156         /* verify client host, strip trailing dot if necessary */
1157         p = buffer_get_string(&b, NULL);
1158         if (((len = strlen(p)) > 0) && p[len - 1] == '.')
1159                 p[len - 1] = '\0';
1160         if (strcmp(p, chost) != 0)
1161                 fail++;
1162         xfree(p);
1163
1164         /* verify client user */
1165         p = buffer_get_string(&b, NULL);
1166         if (strcmp(p, cuser) != 0)
1167                 fail++;
1168         xfree(p);
1169
1170         if (buffer_len(&b) != 0)
1171                 fail++;
1172         buffer_free(&b);
1173         return (fail == 0);
1174 }
1175
1176 int
1177 mm_answer_keyverify(int sock, Buffer *m)
1178 {
1179         Key *key;
1180         u_char *signature, *data, *blob;
1181         u_int signaturelen, datalen, bloblen;
1182         int verified = 0;
1183         int valid_data = 0;
1184
1185         blob = buffer_get_string(m, &bloblen);
1186         signature = buffer_get_string(m, &signaturelen);
1187         data = buffer_get_string(m, &datalen);
1188
1189         if (hostbased_cuser == NULL || hostbased_chost == NULL ||
1190           !monitor_allowed_key(blob, bloblen))
1191                 fatal("%s: bad key, not previously allowed", __func__);
1192
1193         key = key_from_blob(blob, bloblen);
1194         if (key == NULL)
1195                 fatal("%s: bad public key blob", __func__);
1196
1197         switch (key_blobtype) {
1198         case MM_USERKEY:
1199                 valid_data = monitor_valid_userblob(data, datalen);
1200                 break;
1201         case MM_HOSTKEY:
1202                 valid_data = monitor_valid_hostbasedblob(data, datalen,
1203                     hostbased_cuser, hostbased_chost);
1204                 break;
1205         default:
1206                 valid_data = 0;
1207                 break;
1208         }
1209         if (!valid_data)
1210                 fatal("%s: bad signature data blob", __func__);
1211
1212         verified = key_verify(key, signature, signaturelen, data, datalen);
1213         debug3("%s: key %p signature %s",
1214             __func__, key, verified ? "verified" : "unverified");
1215
1216         key_free(key);
1217         xfree(blob);
1218         xfree(signature);
1219         xfree(data);
1220
1221         auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased";
1222
1223         monitor_reset_key_state();
1224
1225         buffer_clear(m);
1226         buffer_put_int(m, verified);
1227         mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m);
1228
1229         return (verified);
1230 }
1231
1232 static void
1233 mm_record_login(Session *s, struct passwd *pw)
1234 {
1235         socklen_t fromlen;
1236         struct sockaddr_storage from;
1237
1238         /*
1239          * Get IP address of client. If the connection is not a socket, let
1240          * the address be 0.0.0.0.
1241          */
1242         memset(&from, 0, sizeof(from));
1243         fromlen = sizeof(from);
1244         if (packet_connection_is_on_socket()) {
1245                 if (getpeername(packet_get_connection_in(),
1246                     (struct sockaddr *)&from, &fromlen) < 0) {
1247                         debug("getpeername: %.100s", strerror(errno));
1248                         cleanup_exit(255);
1249                 }
1250         }
1251         /* Record that there was a login on that tty from the remote host. */
1252         record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
1253             get_remote_name_or_ip(utmp_len, options.use_dns),
1254             (struct sockaddr *)&from, fromlen);
1255 }
1256
1257 static void
1258 mm_session_close(Session *s)
1259 {
1260         debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid);
1261         if (s->ttyfd != -1) {
1262                 debug3("%s: tty %s ptyfd %d",  __func__, s->tty, s->ptyfd);
1263                 session_pty_cleanup2(s);
1264         }
1265         s->used = 0;
1266 }
1267
1268 int
1269 mm_answer_pty(int sock, Buffer *m)
1270 {
1271         extern struct monitor *pmonitor;
1272         Session *s;
1273         int res, fd0;
1274
1275         debug3("%s entering", __func__);
1276
1277         buffer_clear(m);
1278         s = session_new();
1279         if (s == NULL)
1280                 goto error;
1281         s->authctxt = authctxt;
1282         s->pw = authctxt->pw;
1283         s->pid = pmonitor->m_pid;
1284         res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
1285         if (res == 0)
1286                 goto error;
1287         pty_setowner(authctxt->pw, s->tty);
1288
1289         buffer_put_int(m, 1);
1290         buffer_put_cstring(m, s->tty);
1291
1292         /* We need to trick ttyslot */
1293         if (dup2(s->ttyfd, 0) == -1)
1294                 fatal("%s: dup2", __func__);
1295
1296         mm_record_login(s, authctxt->pw);
1297
1298         /* Now we can close the file descriptor again */
1299         close(0);
1300
1301         /* send messages generated by record_login */
1302         buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
1303         buffer_clear(&loginmsg);
1304
1305         mm_request_send(sock, MONITOR_ANS_PTY, m);
1306
1307         mm_send_fd(sock, s->ptyfd);
1308         mm_send_fd(sock, s->ttyfd);
1309
1310         /* make sure nothing uses fd 0 */
1311         if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0)
1312                 fatal("%s: open(/dev/null): %s", __func__, strerror(errno));
1313         if (fd0 != 0)
1314                 error("%s: fd0 %d != 0", __func__, fd0);
1315
1316         /* slave is not needed */
1317         close(s->ttyfd);
1318         s->ttyfd = s->ptyfd;
1319         /* no need to dup() because nobody closes ptyfd */
1320         s->ptymaster = s->ptyfd;
1321
1322         debug3("%s: tty %s ptyfd %d",  __func__, s->tty, s->ttyfd);
1323
1324         return (0);
1325
1326  error:
1327         if (s != NULL)
1328                 mm_session_close(s);
1329         buffer_put_int(m, 0);
1330         mm_request_send(sock, MONITOR_ANS_PTY, m);
1331         return (0);
1332 }
1333
1334 int
1335 mm_answer_pty_cleanup(int sock, Buffer *m)
1336 {
1337         Session *s;
1338         char *tty;
1339
1340         debug3("%s entering", __func__);
1341
1342         tty = buffer_get_string(m, NULL);
1343         if ((s = session_by_tty(tty)) != NULL)
1344                 mm_session_close(s);
1345         buffer_clear(m);
1346         xfree(tty);
1347         return (0);
1348 }
1349
1350 int
1351 mm_answer_sesskey(int sock, Buffer *m)
1352 {
1353         BIGNUM *p;
1354         int rsafail;
1355
1356         /* Turn off permissions */
1357         monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0);
1358
1359         if ((p = BN_new()) == NULL)
1360                 fatal("%s: BN_new", __func__);
1361
1362         buffer_get_bignum2(m, p);
1363
1364         rsafail = ssh1_session_key(p);
1365
1366         buffer_clear(m);
1367         buffer_put_int(m, rsafail);
1368         buffer_put_bignum2(m, p);
1369
1370         BN_clear_free(p);
1371
1372         mm_request_send(sock, MONITOR_ANS_SESSKEY, m);
1373
1374         /* Turn on permissions for sessid passing */
1375         monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1);
1376
1377         return (0);
1378 }
1379
1380 int
1381 mm_answer_sessid(int sock, Buffer *m)
1382 {
1383         int i;
1384
1385         debug3("%s entering", __func__);
1386
1387         if (buffer_len(m) != 16)
1388                 fatal("%s: bad ssh1 session id", __func__);
1389         for (i = 0; i < 16; i++)
1390                 session_id[i] = buffer_get_char(m);
1391
1392         /* Turn on permissions for getpwnam */
1393         monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
1394
1395         return (0);
1396 }
1397
1398 int
1399 mm_answer_rsa_keyallowed(int sock, Buffer *m)
1400 {
1401         BIGNUM *client_n;
1402         Key *key = NULL;
1403         u_char *blob = NULL;
1404         u_int blen = 0;
1405         int allowed = 0;
1406
1407         debug3("%s entering", __func__);
1408
1409         auth_method = "rsa";
1410         if (options.rsa_authentication && authctxt->valid) {
1411                 if ((client_n = BN_new()) == NULL)
1412                         fatal("%s: BN_new", __func__);
1413                 buffer_get_bignum2(m, client_n);
1414                 allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key);
1415                 BN_clear_free(client_n);
1416         }
1417         buffer_clear(m);
1418         buffer_put_int(m, allowed);
1419         buffer_put_int(m, forced_command != NULL);
1420
1421         /* clear temporarily storage (used by generate challenge) */
1422         monitor_reset_key_state();
1423
1424         if (allowed && key != NULL) {
1425                 key->type = KEY_RSA;    /* cheat for key_to_blob */
1426                 if (key_to_blob(key, &blob, &blen) == 0)
1427                         fatal("%s: key_to_blob failed", __func__);
1428                 buffer_put_string(m, blob, blen);
1429
1430                 /* Save temporarily for comparison in verify */
1431                 key_blob = blob;
1432                 key_bloblen = blen;
1433                 key_blobtype = MM_RSAUSERKEY;
1434         }
1435         if (key != NULL)
1436                 key_free(key);
1437
1438         mm_append_debug(m);
1439
1440         mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m);
1441
1442         monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1443         monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0);
1444         return (0);
1445 }
1446
1447 int
1448 mm_answer_rsa_challenge(int sock, Buffer *m)
1449 {
1450         Key *key = NULL;
1451         u_char *blob;
1452         u_int blen;
1453
1454         debug3("%s entering", __func__);
1455
1456         if (!authctxt->valid)
1457                 fatal("%s: authctxt not valid", __func__);
1458         blob = buffer_get_string(m, &blen);
1459         if (!monitor_allowed_key(blob, blen))
1460                 fatal("%s: bad key, not previously allowed", __func__);
1461         if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1462                 fatal("%s: key type mismatch", __func__);
1463         if ((key = key_from_blob(blob, blen)) == NULL)
1464                 fatal("%s: received bad key", __func__);
1465
1466         if (ssh1_challenge)
1467                 BN_clear_free(ssh1_challenge);
1468         ssh1_challenge = auth_rsa_generate_challenge(key);
1469
1470         buffer_clear(m);
1471         buffer_put_bignum2(m, ssh1_challenge);
1472
1473         debug3("%s sending reply", __func__);
1474         mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m);
1475
1476         monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1);
1477
1478         xfree(blob);
1479         key_free(key);
1480         return (0);
1481 }
1482
1483 int
1484 mm_answer_rsa_response(int sock, Buffer *m)
1485 {
1486         Key *key = NULL;
1487         u_char *blob, *response;
1488         u_int blen, len;
1489         int success;
1490
1491         debug3("%s entering", __func__);
1492
1493         if (!authctxt->valid)
1494                 fatal("%s: authctxt not valid", __func__);
1495         if (ssh1_challenge == NULL)
1496                 fatal("%s: no ssh1_challenge", __func__);
1497
1498         blob = buffer_get_string(m, &blen);
1499         if (!monitor_allowed_key(blob, blen))
1500                 fatal("%s: bad key, not previously allowed", __func__);
1501         if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1502                 fatal("%s: key type mismatch: %d", __func__, key_blobtype);
1503         if ((key = key_from_blob(blob, blen)) == NULL)
1504                 fatal("%s: received bad key", __func__);
1505         response = buffer_get_string(m, &len);
1506         if (len != 16)
1507                 fatal("%s: received bad response to challenge", __func__);
1508         success = auth_rsa_verify_response(key, ssh1_challenge, response);
1509
1510         xfree(blob);
1511         key_free(key);
1512         xfree(response);
1513
1514         auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa";
1515
1516         /* reset state */
1517         BN_clear_free(ssh1_challenge);
1518         ssh1_challenge = NULL;
1519         monitor_reset_key_state();
1520
1521         buffer_clear(m);
1522         buffer_put_int(m, success);
1523         mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m);
1524
1525         return (success);
1526 }
1527
1528 int
1529 mm_answer_term(int sock, Buffer *req)
1530 {
1531         extern struct monitor *pmonitor;
1532         int res, status;
1533
1534         debug3("%s: tearing down sessions", __func__);
1535
1536         /* The child is terminating */
1537         session_destroy_all(&mm_session_close);
1538
1539         while (waitpid(pmonitor->m_pid, &status, 0) == -1)
1540                 if (errno != EINTR)
1541                         exit(1);
1542
1543         res = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
1544
1545         /* Terminate process */
1546         exit(res);
1547 }
1548
1549 #ifdef SSH_AUDIT_EVENTS
1550 /* Report that an audit event occurred */
1551 int
1552 mm_answer_audit_event(int socket, Buffer *m)
1553 {
1554         ssh_audit_event_t event;
1555
1556         debug3("%s entering", __func__);
1557
1558         event = buffer_get_int(m);
1559         switch(event) {
1560         case SSH_AUTH_FAIL_PUBKEY:
1561         case SSH_AUTH_FAIL_HOSTBASED:
1562         case SSH_AUTH_FAIL_GSSAPI:
1563         case SSH_LOGIN_EXCEED_MAXTRIES:
1564         case SSH_LOGIN_ROOT_DENIED:
1565         case SSH_CONNECTION_CLOSE:
1566         case SSH_INVALID_USER:
1567                 audit_event(event);
1568                 break;
1569         default:
1570                 fatal("Audit event type %d not permitted", event);
1571         }
1572
1573         return (0);
1574 }
1575
1576 int
1577 mm_answer_audit_command(int socket, Buffer *m)
1578 {
1579         u_int len;
1580         char *cmd;
1581
1582         debug3("%s entering", __func__);
1583         cmd = buffer_get_string(m, &len);
1584         /* sanity check command, if so how? */
1585         audit_run_command(cmd);
1586         xfree(cmd);
1587         return (0);
1588 }
1589 #endif /* SSH_AUDIT_EVENTS */
1590
1591 void
1592 monitor_apply_keystate(struct monitor *pmonitor)
1593 {
1594         if (compat20) {
1595                 set_newkeys(MODE_IN);
1596                 set_newkeys(MODE_OUT);
1597         } else {
1598                 packet_set_protocol_flags(child_state.ssh1protoflags);
1599                 packet_set_encryption_key(child_state.ssh1key,
1600                     child_state.ssh1keylen, child_state.ssh1cipher);
1601                 xfree(child_state.ssh1key);
1602         }
1603
1604         /* for rc4 and other stateful ciphers */
1605         packet_set_keycontext(MODE_OUT, child_state.keyout);
1606         xfree(child_state.keyout);
1607         packet_set_keycontext(MODE_IN, child_state.keyin);
1608         xfree(child_state.keyin);
1609
1610         if (!compat20) {
1611                 packet_set_iv(MODE_OUT, child_state.ivout);
1612                 xfree(child_state.ivout);
1613                 packet_set_iv(MODE_IN, child_state.ivin);
1614                 xfree(child_state.ivin);
1615         }
1616
1617         memcpy(&incoming_stream, &child_state.incoming,
1618             sizeof(incoming_stream));
1619         memcpy(&outgoing_stream, &child_state.outgoing,
1620             sizeof(outgoing_stream));
1621
1622         /* Update with new address */
1623         if (options.compression)
1624                 mm_init_compression(pmonitor->m_zlib);
1625
1626         /* Network I/O buffers */
1627         /* XXX inefficient for large buffers, need: buffer_init_from_string */
1628         buffer_clear(&input);
1629         buffer_append(&input, child_state.input, child_state.ilen);
1630         memset(child_state.input, 0, child_state.ilen);
1631         xfree(child_state.input);
1632
1633         buffer_clear(&output);
1634         buffer_append(&output, child_state.output, child_state.olen);
1635         memset(child_state.output, 0, child_state.olen);
1636         xfree(child_state.output);
1637 }
1638
1639 static Kex *
1640 mm_get_kex(Buffer *m)
1641 {
1642         Kex *kex;
1643         void *blob;
1644         u_int bloblen;
1645
1646         kex = xcalloc(1, sizeof(*kex));
1647         kex->session_id = buffer_get_string(m, &kex->session_id_len);
1648         if ((session_id2 == NULL) ||
1649             (kex->session_id_len != session_id2_len) ||
1650             (memcmp(kex->session_id, session_id2, session_id2_len) != 0))
1651                 fatal("mm_get_get: internal error: bad session id");
1652         kex->we_need = buffer_get_int(m);
1653         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1654         kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1655         kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1656         kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1657         kex->server = 1;
1658         kex->hostkey_type = buffer_get_int(m);
1659         kex->kex_type = buffer_get_int(m);
1660         blob = buffer_get_string(m, &bloblen);
1661         buffer_init(&kex->my);
1662         buffer_append(&kex->my, blob, bloblen);
1663         xfree(blob);
1664         blob = buffer_get_string(m, &bloblen);
1665         buffer_init(&kex->peer);
1666         buffer_append(&kex->peer, blob, bloblen);
1667         xfree(blob);
1668         kex->done = 1;
1669         kex->flags = buffer_get_int(m);
1670         kex->client_version_string = buffer_get_string(m, NULL);
1671         kex->server_version_string = buffer_get_string(m, NULL);
1672         kex->load_host_key=&get_hostkey_by_type;
1673         kex->host_key_index=&get_hostkey_index;
1674
1675         return (kex);
1676 }
1677
1678 /* This function requries careful sanity checking */
1679
1680 void
1681 mm_get_keystate(struct monitor *pmonitor)
1682 {
1683         Buffer m;
1684         u_char *blob, *p;
1685         u_int bloblen, plen;
1686         u_int32_t seqnr, packets;
1687         u_int64_t blocks;
1688
1689         debug3("%s: Waiting for new keys", __func__);
1690
1691         buffer_init(&m);
1692         mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, &m);
1693         if (!compat20) {
1694                 child_state.ssh1protoflags = buffer_get_int(&m);
1695                 child_state.ssh1cipher = buffer_get_int(&m);
1696                 child_state.ssh1key = buffer_get_string(&m,
1697                     &child_state.ssh1keylen);
1698                 child_state.ivout = buffer_get_string(&m,
1699                     &child_state.ivoutlen);
1700                 child_state.ivin = buffer_get_string(&m, &child_state.ivinlen);
1701                 goto skip;
1702         } else {
1703                 /* Get the Kex for rekeying */
1704                 *pmonitor->m_pkex = mm_get_kex(&m);
1705         }
1706
1707         blob = buffer_get_string(&m, &bloblen);
1708         current_keys[MODE_OUT] = mm_newkeys_from_blob(blob, bloblen);
1709         xfree(blob);
1710
1711         debug3("%s: Waiting for second key", __func__);
1712         blob = buffer_get_string(&m, &bloblen);
1713         current_keys[MODE_IN] = mm_newkeys_from_blob(blob, bloblen);
1714         xfree(blob);
1715
1716         /* Now get sequence numbers for the packets */
1717         seqnr = buffer_get_int(&m);
1718         blocks = buffer_get_int64(&m);
1719         packets = buffer_get_int(&m);
1720         packet_set_state(MODE_OUT, seqnr, blocks, packets);
1721         seqnr = buffer_get_int(&m);
1722         blocks = buffer_get_int64(&m);
1723         packets = buffer_get_int(&m);
1724         packet_set_state(MODE_IN, seqnr, blocks, packets);
1725
1726  skip:
1727         /* Get the key context */
1728         child_state.keyout = buffer_get_string(&m, &child_state.keyoutlen);
1729         child_state.keyin  = buffer_get_string(&m, &child_state.keyinlen);
1730
1731         debug3("%s: Getting compression state", __func__);
1732         /* Get compression state */
1733         p = buffer_get_string(&m, &plen);
1734         if (plen != sizeof(child_state.outgoing))
1735                 fatal("%s: bad request size", __func__);
1736         memcpy(&child_state.outgoing, p, sizeof(child_state.outgoing));
1737         xfree(p);
1738
1739         p = buffer_get_string(&m, &plen);
1740         if (plen != sizeof(child_state.incoming))
1741                 fatal("%s: bad request size", __func__);
1742         memcpy(&child_state.incoming, p, sizeof(child_state.incoming));
1743         xfree(p);
1744
1745         /* Network I/O buffers */
1746         debug3("%s: Getting Network I/O buffers", __func__);
1747         child_state.input = buffer_get_string(&m, &child_state.ilen);
1748         child_state.output = buffer_get_string(&m, &child_state.olen);
1749
1750         buffer_free(&m);
1751 }
1752
1753
1754 /* Allocation functions for zlib */
1755 void *
1756 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size)
1757 {
1758         size_t len = (size_t) size * ncount;
1759         void *address;
1760
1761         if (len == 0 || ncount > SIZE_T_MAX / size)
1762                 fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size);
1763
1764         address = mm_malloc(mm, len);
1765
1766         return (address);
1767 }
1768
1769 void
1770 mm_zfree(struct mm_master *mm, void *address)
1771 {
1772         mm_free(mm, address);
1773 }
1774
1775 void
1776 mm_init_compression(struct mm_master *mm)
1777 {
1778         outgoing_stream.zalloc = (alloc_func)mm_zalloc;
1779         outgoing_stream.zfree = (free_func)mm_zfree;
1780         outgoing_stream.opaque = mm;
1781
1782         incoming_stream.zalloc = (alloc_func)mm_zalloc;
1783         incoming_stream.zfree = (free_func)mm_zfree;
1784         incoming_stream.opaque = mm;
1785 }
1786
1787 /* XXX */
1788
1789 #define FD_CLOSEONEXEC(x) do { \
1790         if (fcntl(x, F_SETFD, 1) == -1) \
1791                 fatal("fcntl(%d, F_SETFD)", x); \
1792 } while (0)
1793
1794 static void
1795 monitor_socketpair(int *pair)
1796 {
1797 #ifdef HAVE_SOCKETPAIR
1798         if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
1799                 fatal("%s: socketpair", __func__);
1800 #else
1801         fatal("%s: UsePrivilegeSeparation=yes not supported",
1802             __func__);
1803 #endif
1804         FD_CLOSEONEXEC(pair[0]);
1805         FD_CLOSEONEXEC(pair[1]);
1806 }
1807
1808 #define MM_MEMSIZE      65536
1809
1810 struct monitor *
1811 monitor_init(void)
1812 {
1813         struct monitor *mon;
1814         int pair[2];
1815
1816         mon = xcalloc(1, sizeof(*mon));
1817
1818         monitor_socketpair(pair);
1819
1820         mon->m_recvfd = pair[0];
1821         mon->m_sendfd = pair[1];
1822
1823         /* Used to share zlib space across processes */
1824         if (options.compression) {
1825                 mon->m_zback = mm_create(NULL, MM_MEMSIZE);
1826                 mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE);
1827
1828                 /* Compression needs to share state across borders */
1829                 mm_init_compression(mon->m_zlib);
1830         }
1831
1832         return mon;
1833 }
1834
1835 void
1836 monitor_reinit(struct monitor *mon)
1837 {
1838         int pair[2];
1839
1840         monitor_socketpair(pair);
1841
1842         mon->m_recvfd = pair[0];
1843         mon->m_sendfd = pair[1];
1844 }
1845
1846 #ifdef GSSAPI
1847 int
1848 mm_answer_gss_setup_ctx(int sock, Buffer *m)
1849 {
1850         gss_OID_desc goid;
1851         OM_uint32 major;
1852         u_int len;
1853
1854         goid.elements = buffer_get_string(m, &len);
1855         goid.length = len;
1856
1857         major = ssh_gssapi_server_ctx(&gsscontext, &goid);
1858
1859         xfree(goid.elements);
1860
1861         buffer_clear(m);
1862         buffer_put_int(m, major);
1863
1864         mm_request_send(sock, MONITOR_ANS_GSSSETUP, m);
1865
1866         /* Now we have a context, enable the step */
1867         monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1);
1868
1869         return (0);
1870 }
1871
1872 int
1873 mm_answer_gss_accept_ctx(int sock, Buffer *m)
1874 {
1875         gss_buffer_desc in;
1876         gss_buffer_desc out = GSS_C_EMPTY_BUFFER;
1877         OM_uint32 major, minor;
1878         OM_uint32 flags = 0; /* GSI needs this */
1879         u_int len;
1880
1881         in.value = buffer_get_string(m, &len);
1882         in.length = len;
1883         major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
1884         xfree(in.value);
1885
1886         buffer_clear(m);
1887         buffer_put_int(m, major);
1888         buffer_put_string(m, out.value, out.length);
1889         buffer_put_int(m, flags);
1890         mm_request_send(sock, MONITOR_ANS_GSSSTEP, m);
1891
1892         gss_release_buffer(&minor, &out);
1893
1894         if (major == GSS_S_COMPLETE) {
1895                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
1896                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1897                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
1898         }
1899         return (0);
1900 }
1901
1902 int
1903 mm_answer_gss_checkmic(int sock, Buffer *m)
1904 {
1905         gss_buffer_desc gssbuf, mic;
1906         OM_uint32 ret;
1907         u_int len;
1908
1909         gssbuf.value = buffer_get_string(m, &len);
1910         gssbuf.length = len;
1911         mic.value = buffer_get_string(m, &len);
1912         mic.length = len;
1913
1914         ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic);
1915
1916         xfree(gssbuf.value);
1917         xfree(mic.value);
1918
1919         buffer_clear(m);
1920         buffer_put_int(m, ret);
1921
1922         mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m);
1923
1924         if (!GSS_ERROR(ret))
1925                 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
1926
1927         return (0);
1928 }
1929
1930 int
1931 mm_answer_gss_userok(int sock, Buffer *m)
1932 {
1933         int authenticated;
1934
1935         authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
1936
1937         buffer_clear(m);
1938         buffer_put_int(m, authenticated);
1939
1940         debug3("%s: sending result %d", __func__, authenticated);
1941         mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
1942
1943         auth_method = "gssapi-with-mic";
1944
1945         /* Monitor loop will terminate if authenticated */
1946         return (authenticated);
1947 }
1948 #endif /* GSSAPI */