openssh/sshconnect2.c

   1 /* $OpenBSD: sshconnect2.c,v 1.171 2009/03/05 07:18:19 djm Exp $ */
   2 /*
   3  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   4  * Copyright (c) 2008 Damien Miller.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "includes.h"
  28
  29 #include <sys/types.h>
  30 #include <sys/socket.h>
  31 #include <sys/wait.h>
  32 #include <sys/stat.h>
  33
  34 #include <errno.h>
  35 #include <netdb.h>
  36 #include <pwd.h>
  37 #include <signal.h>
  38 #include <stdarg.h>
  39 #include <stdio.h>
  40 #include <string.h>
  41 #include <unistd.h>
  42 #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H)
  43 #include <vis.h>
  44 #endif
  45
  46 #include "openbsd-compat/sys-queue.h"
  47
  48 #include "xmalloc.h"
  49 #include "ssh.h"
  50 #include "ssh2.h"
  51 #include "buffer.h"
  52 #include "packet.h"
  53 #include "compat.h"
  54 #include "cipher.h"
  55 #include "key.h"
  56 #include "kex.h"
  57 #include "myproposal.h"
  58 #include "sshconnect.h"
  59 #include "authfile.h"
  60 #include "dh.h"
  61 #include "authfd.h"
  62 #include "log.h"
  63 #include "readconf.h"
  64 #include "misc.h"
  65 #include "match.h"
  66 #include "dispatch.h"
  67 #include "canohost.h"
  68 #include "msg.h"
  69 #include "pathnames.h"
  70 #include "uidswap.h"
  71 #include "schnorr.h"
  72 #include "jpake.h"
  73
  74 #ifdef GSSAPI
  75 #include "ssh-gss.h"
  76 #endif
  77
  78 /* import */
  79 extern char *client_version_string;
  80 extern char *server_version_string;
  81 extern Options options;
  82 extern Kex *xxx_kex;
  83
  84 /* tty_flag is set in ssh.c. use this in ssh_userauth2 */
  85 /* if it is set then prevent the switch to the null cipher */
  86
  87 extern int tty_flag;
  88
  89 /* tty_flag is set in ssh.c. use this in ssh_userauth2 */
  90 /* if it is set then prevent the switch to the null cipher */
  91
  92 extern int tty_flag;
  93
  94 /* tty_flag is set in ssh.c. use this in ssh_userauth2 */
  95 /* if it is set then prevent the switch to the null cipher */
  96
  97 extern int tty_flag;
  98
  99 /*
 100  * SSH2 key exchange
 101  */
 102
 103 u_char *session_id2 = NULL;
 104 u_int session_id2_len = 0;
 105
 106 char *xxx_host;
 107 struct sockaddr *xxx_hostaddr;
 108
 109 Kex *xxx_kex = NULL;
 110
 111 static int
 112 verify_host_key_callback(Key *hostkey)
 113 {
 114         if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
 115                 fatal("Host key verification failed.");
 116         return 0;
 117 }
 118
 119 void
 120 ssh_kex2(char *host, struct sockaddr *hostaddr)
 121 {
 122         Kex *kex;
 123
 124 #ifdef GSSAPI
 125         char *orig = NULL, *gss = NULL;
 126         char *gss_host = NULL;
 127 #endif
 128
 129         xxx_host = host;
 130         xxx_hostaddr = hostaddr;
 131
 132 #ifdef GSSAPI
 133         if (options.gss_keyex) {
 134                 /* Add the GSSAPI mechanisms currently supported on this
 135                  * client to the key exchange algorithm proposal */
 136                 orig = myproposal[PROPOSAL_KEX_ALGS];
 137
 138                 if (options.gss_trust_dns)
 139                         gss_host = (char *)get_canonical_hostname(1);
 140                 else
 141                         gss_host = host;
 142
 143                 gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity);
 144                 if (gss) {
 145                         debug("Offering GSSAPI proposal: %s", gss);
 146                         xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
 147                             "%s,%s", gss, orig);
 148                 }
 149         }
 150 #endif
 151
 152         if (options.ciphers == (char *)-1) {
 153                 logit("No valid ciphers for protocol version 2 given, using defaults.");
 154                 options.ciphers = NULL;
 155         }
 156         if (options.ciphers != NULL) {
 157                 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 158                 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
 159         }
 160         myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 161             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
 162         myproposal[PROPOSAL_ENC_ALGS_STOC] =
 163             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
 164         if (options.compression) {
 165                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 166                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
 167         } else {
 168                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 169                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
 170         }
 171         if (options.macs != NULL) {
 172                 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
 173                 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
 174         }
 175         if (options.hostkeyalgorithms != NULL)
 176                 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
 177                     options.hostkeyalgorithms;
 178
 179 #ifdef GSSAPI
 180         /* If we've got GSSAPI algorithms, then we also support the
 181          * 'null' hostkey, as a last resort */
 182         if (options.gss_keyex && gss) {
 183                 orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
 184                 xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],
 185                     "%s,null", orig);
 186                 xfree(gss);
 187         }
 188 #endif
 189
 190         if (options.rekey_limit)
 191                 packet_set_rekey_limit((u_int32_t)options.rekey_limit);
 192
 193         /* start key exchange */
 194         kex = kex_setup(myproposal);
 195         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
 196         kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
 197         kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
 198         kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
 199 #ifdef GSSAPI
 200         if (options.gss_keyex) {
 201                 kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
 202                 kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client;
 203                 kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client;
 204         }
 205 #endif
 206         kex->client_version_string=client_version_string;
 207         kex->server_version_string=server_version_string;
 208         kex->verify_host_key=&verify_host_key_callback;
 209
 210 #ifdef GSSAPI
 211         if (options.gss_keyex) {
 212                 kex->gss_deleg_creds = options.gss_deleg_creds;
 213                 kex->gss_trust_dns = options.gss_trust_dns;
 214                 kex->gss_client = options.gss_client_identity;
 215                 kex->gss_host = gss_host;
 216         }
 217 #endif
 218
 219         xxx_kex = kex;
 220
 221         dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
 222
 223         session_id2 = kex->session_id;
 224         session_id2_len = kex->session_id_len;
 225
 226 #ifdef DEBUG_KEXDH
 227         /* send 1st encrypted/maced/compressed message */
 228         packet_start(SSH2_MSG_IGNORE);
 229         packet_put_cstring("markus");
 230         packet_send();
 231         packet_write_wait();
 232 #endif
 233 }
 234
 235 /*
 236  * Authenticate user
 237  */
 238
 239 typedef struct Authctxt Authctxt;
 240 typedef struct Authmethod Authmethod;
 241 typedef struct identity Identity;
 242 typedef struct idlist Idlist;
 243
 244 struct identity {
 245         TAILQ_ENTRY(identity) next;
 246         AuthenticationConnection *ac;   /* set if agent supports key */
 247         Key     *key;                   /* public/private key */
 248         char    *filename;              /* comment for agent-only keys */
 249         int     tried;
 250         int     isprivate;              /* key points to the private key */
 251 };
 252 TAILQ_HEAD(idlist, identity);
 253
 254 struct Authctxt {
 255         const char *server_user;
 256         const char *local_user;
 257         const char *host;
 258         const char *service;
 259         Authmethod *method;
 260         int success;
 261         char *authlist;
 262         /* pubkey */
 263         Idlist keys;
 264         AuthenticationConnection *agent;
 265         /* hostbased */
 266         Sensitive *sensitive;
 267         /* kbd-interactive */
 268         int info_req_seen;
 269         /* generic */
 270         void *methoddata;
 271 };
 272 struct Authmethod {
 273         char    *name;          /* string to compare against server's list */
 274         int     (*userauth)(Authctxt *authctxt);
 275         void    (*cleanup)(Authctxt *authctxt);
 276         int     *enabled;       /* flag in option struct that enables method */
 277         int     *batch_flag;    /* flag in option struct that disables method */
 278 };
 279
 280 void    input_userauth_success(int, u_int32_t, void *);
 281 void    input_userauth_failure(int, u_int32_t, void *);
 282 void    input_userauth_banner(int, u_int32_t, void *);
 283 void    input_userauth_error(int, u_int32_t, void *);
 284 void    input_userauth_info_req(int, u_int32_t, void *);
 285 void    input_userauth_pk_ok(int, u_int32_t, void *);
 286 void    input_userauth_passwd_changereq(int, u_int32_t, void *);
 287 void    input_userauth_jpake_server_step1(int, u_int32_t, void *);
 288 void    input_userauth_jpake_server_step2(int, u_int32_t, void *);
 289 void    input_userauth_jpake_server_confirm(int, u_int32_t, void *);
 290
 291 int     userauth_none(Authctxt *);
 292 int     userauth_pubkey(Authctxt *);
 293 int     userauth_passwd(Authctxt *);
 294 int     userauth_kbdint(Authctxt *);
 295 int     userauth_hostbased(Authctxt *);
 296 int     userauth_jpake(Authctxt *);
 297
 298 void    userauth_jpake_cleanup(Authctxt *);
 299
 300 #ifdef GSSAPI
 301 int     userauth_external(Authctxt *authctxt);
 302 int     userauth_gssapi(Authctxt *authctxt);
 303 int     userauth_gssapi_with_mic(Authctxt *authctxt);
 304 int     userauth_gssapi_without_mic(Authctxt *authctxt);
 305 void    input_gssapi_response(int type, u_int32_t, void *);
 306 void    input_gssapi_token(int type, u_int32_t, void *);
 307 void    input_gssapi_hash(int type, u_int32_t, void *);
 308 void    input_gssapi_error(int, u_int32_t, void *);
 309 void    input_gssapi_errtok(int, u_int32_t, void *);
 310 int     userauth_gsskeyex(Authctxt *authctxt);
 311 #endif
 312
 313 void    userauth(Authctxt *, char *);
 314
 315 static int sign_and_send_pubkey(Authctxt *, Identity *);
 316 static void pubkey_prepare(Authctxt *);
 317 static void pubkey_cleanup(Authctxt *);
 318 static Key *load_identity_file(char *);
 319
 320 static Authmethod *authmethod_get(char *authlist);
 321 static Authmethod *authmethod_lookup(const char *name);
 322 static char *authmethods_get(void);
 323
 324 Authmethod authmethods[] = {
 325 #ifdef GSSAPI
 326         {"gssapi-keyex",
 327                 userauth_gsskeyex,
 328                 NULL,
 329                 &options.gss_authentication,
 330                 NULL},
 331         {"external-keyx",
 332                 userauth_external,
 333                 NULL,
 334                 &options.gss_authentication,
 335                 NULL},
 336         {"gssapi-with-mic",
 337                 userauth_gssapi,
 338                 NULL,
 339                 &options.gss_authentication,
 340                 NULL},
 341         {"gssapi",
 342                 userauth_gssapi,
 343                 NULL,
 344                 &options.gss_authentication,
 345                 NULL},
 346 #endif
 347         {"hostbased",
 348                 userauth_hostbased,
 349                 NULL,
 350                 &options.hostbased_authentication,
 351                 NULL},
 352         {"publickey",
 353                 userauth_pubkey,
 354                 NULL,
 355                 &options.pubkey_authentication,
 356                 NULL},
 357 #ifdef JPAKE
 358         {"jpake-01@openssh.com",
 359                 userauth_jpake,
 360                 userauth_jpake_cleanup,
 361                 &options.zero_knowledge_password_authentication,
 362                 &options.batch_mode},
 363 #endif
 364         {"keyboard-interactive",
 365                 userauth_kbdint,
 366                 NULL,
 367                 &options.kbd_interactive_authentication,
 368                 &options.batch_mode},
 369         {"password",
 370                 userauth_passwd,
 371                 NULL,
 372                 &options.password_authentication,
 373                 &options.batch_mode},
 374         {"none",
 375                 userauth_none,
 376                 NULL,
 377                 NULL,
 378                 NULL},
 379         {NULL, NULL, NULL, NULL, NULL}
 380 };
 381
 382 void
 383 ssh_userauth2(const char *local_user, const char *server_user, char *host,
 384     Sensitive *sensitive)
 385 {
 386         Authctxt authctxt;
 387         int type;
 388
 389         if (options.challenge_response_authentication)
 390                 options.kbd_interactive_authentication = 1;
 391
 392         packet_start(SSH2_MSG_SERVICE_REQUEST);
 393         packet_put_cstring("ssh-userauth");
 394         packet_send();
 395         debug("SSH2_MSG_SERVICE_REQUEST sent");
 396         packet_write_wait();
 397         type = packet_read();
 398         if (type != SSH2_MSG_SERVICE_ACCEPT)
 399                 fatal("Server denied authentication request: %d", type);
 400         if (packet_remaining() > 0) {
 401                 char *reply = packet_get_string(NULL);
 402                 debug2("service_accept: %s", reply);
 403                 xfree(reply);
 404         } else {
 405                 debug2("buggy server: service_accept w/o service");
 406         }
 407         packet_check_eom();
 408         debug("SSH2_MSG_SERVICE_ACCEPT received");
 409
 410         if (options.preferred_authentications == NULL)
 411                 options.preferred_authentications = authmethods_get();
 412
 413         /* setup authentication context */
 414         memset(&authctxt, 0, sizeof(authctxt));
 415         pubkey_prepare(&authctxt);
 416         authctxt.server_user = server_user;
 417         authctxt.local_user = local_user;
 418         authctxt.host = host;
 419         authctxt.service = "ssh-connection";            /* service name */
 420         authctxt.success = 0;
 421         authctxt.method = authmethod_lookup("none");
 422         authctxt.authlist = NULL;
 423         authctxt.methoddata = NULL;
 424         authctxt.sensitive = sensitive;
 425         authctxt.info_req_seen = 0;
 426         if (authctxt.method == NULL)
 427                 fatal("ssh_userauth2: internal error: cannot send userauth none request");
 428
 429         /* initial userauth request */
 430         userauth_none(&authctxt);
 431
 432         dispatch_init(&input_userauth_error);
 433         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
 434         dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
 435         dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
 436         dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt);     /* loop until success */
 437
 438         pubkey_cleanup(&authctxt);
 439         dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
 440
 441         /* if the user wants to use the none cipher do it */
 442         /* post authentication and only if the right conditions are met */
 443         /* both of the NONE commands must be true and there must be no */
 444         /* tty allocated */
 445         if ((options.none_switch == 1) && (options.none_enabled == 1))
 446         {
 447                 if (!tty_flag) /* no null on tty sessions */
 448                 {
 449                         debug("Requesting none rekeying...");
 450                         myproposal[PROPOSAL_ENC_ALGS_STOC] = "none";
 451                         myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none";
 452                         kex_prop2buf(&xxx_kex->my,myproposal);
 453                         packet_request_rekeying();
 454                         fprintf(stderr, "WARNING: ENABLED NONE CIPHER\n");
 455                 }
 456                 else
 457                 {
 458                         /* requested NONE cipher when in a tty */
 459                         debug("Cannot switch to NONE cipher with tty allocated");
 460                         fprintf(stderr, "NONE cipher switch disabled when a TTY is allocated\n");
 461                 }
 462         }
 463         debug("Authentication succeeded (%s).", authctxt.method->name);
 464 }
 465
 466 void
 467 userauth(Authctxt *authctxt, char *authlist)
 468 {
 469         if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
 470                 authctxt->method->cleanup(authctxt);
 471
 472         if (authctxt->methoddata) {
 473                 xfree(authctxt->methoddata);
 474                 authctxt->methoddata = NULL;
 475         }
 476         if (authlist == NULL) {
 477                 authlist = authctxt->authlist;
 478         } else {
 479                 if (authctxt->authlist)
 480                         xfree(authctxt->authlist);
 481                 authctxt->authlist = authlist;
 482         }
 483         for (;;) {
 484                 Authmethod *method = authmethod_get(authlist);
 485                 if (method == NULL)
 486                         fatal("Permission denied (%s).", authlist);
 487                 authctxt->method = method;
 488
 489                 /* reset the per method handler */
 490                 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
 491                     SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
 492
 493                 /* and try new method */
 494                 if (method->userauth(authctxt) != 0) {
 495                         debug2("we sent a %s packet, wait for reply", method->name);
 496                         break;
 497                 } else {
 498                         debug2("we did not send a packet, disable method");
 499                         method->enabled = NULL;
 500                 }
 501         }
 502 }
 503
 504 /* ARGSUSED */
 505 void
 506 input_userauth_error(int type, u_int32_t seq, void *ctxt)
 507 {
 508         fatal("input_userauth_error: bad message during authentication: "
 509             "type %d", type);
 510 }
 511
 512 /* ARGSUSED */
 513 void
 514 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
 515 {
 516         char *msg, *raw, *lang;
 517         u_int len;
 518
 519         debug3("input_userauth_banner");
 520         raw = packet_get_string(&len);
 521         lang = packet_get_string(NULL);
 522         if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) {
 523                 if (len > 65536)
 524                         len = 65536;
 525                 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */
 526                 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL);
 527                 fprintf(stderr, "%s", msg);
 528                 xfree(msg);
 529         }
 530         xfree(raw);
 531         xfree(lang);
 532 }
 533
 534 /* ARGSUSED */
 535 void
 536 input_userauth_success(int type, u_int32_t seq, void *ctxt)
 537 {
 538         Authctxt *authctxt = ctxt;
 539         if (authctxt == NULL)
 540                 fatal("input_userauth_success: no authentication context");
 541         if (authctxt->authlist) {
 542                 xfree(authctxt->authlist);
 543                 authctxt->authlist = NULL;
 544         }
 545         if (authctxt->methoddata) {
 546                 xfree(authctxt->methoddata);
 547                 authctxt->methoddata = NULL;
 548         }
 549         authctxt->success = 1;                  /* break out */
 550 }
 551
 552 /* ARGSUSED */
 553 void
 554 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
 555 {
 556         Authctxt *authctxt = ctxt;
 557         char *authlist = NULL;
 558         int partial;
 559
 560         if (authctxt == NULL)
 561                 fatal("input_userauth_failure: no authentication context");
 562
 563         authlist = packet_get_string(NULL);
 564         partial = packet_get_char();
 565         packet_check_eom();
 566
 567         if (partial != 0)
 568                 logit("Authenticated with partial success.");
 569         debug("Authentications that can continue: %s", authlist);
 570
 571         userauth(authctxt, authlist);
 572 }
 573
 574 /* ARGSUSED */
 575 void
 576 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
 577 {
 578         Authctxt *authctxt = ctxt;
 579         Key *key = NULL;
 580         Identity *id = NULL;
 581         Buffer b;
 582         int pktype, sent = 0;
 583         u_int alen, blen;
 584         char *pkalg, *fp;
 585         u_char *pkblob;
 586
 587         if (authctxt == NULL)
 588                 fatal("input_userauth_pk_ok: no authentication context");
 589         if (datafellows & SSH_BUG_PKOK) {
 590                 /* this is similar to SSH_BUG_PKAUTH */
 591                 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
 592                 pkblob = packet_get_string(&blen);
 593                 buffer_init(&b);
 594                 buffer_append(&b, pkblob, blen);
 595                 pkalg = buffer_get_string(&b, &alen);
 596                 buffer_free(&b);
 597         } else {
 598                 pkalg = packet_get_string(&alen);
 599                 pkblob = packet_get_string(&blen);
 600         }
 601         packet_check_eom();
 602
 603         debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
 604
 605         if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
 606                 debug("unknown pkalg %s", pkalg);
 607                 goto done;
 608         }
 609         if ((key = key_from_blob(pkblob, blen)) == NULL) {
 610                 debug("no key from blob. pkalg %s", pkalg);
 611                 goto done;
 612         }
 613         if (key->type != pktype) {
 614                 error("input_userauth_pk_ok: type mismatch "
 615                     "for decoded key (received %d, expected %d)",
 616                     key->type, pktype);
 617                 goto done;
 618         }
 619         fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
 620         debug2("input_userauth_pk_ok: fp %s", fp);
 621         xfree(fp);
 622
 623         /*
 624          * search keys in the reverse order, because last candidate has been
 625          * moved to the end of the queue.  this also avoids confusion by
 626          * duplicate keys
 627          */
 628         TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
 629                 if (key_equal(key, id->key)) {
 630                         sent = sign_and_send_pubkey(authctxt, id);
 631                         break;
 632                 }
 633         }
 634 done:
 635         if (key != NULL)
 636                 key_free(key);
 637         xfree(pkalg);
 638         xfree(pkblob);
 639
 640         /* try another method if we did not send a packet */
 641         if (sent == 0)
 642                 userauth(authctxt, NULL);
 643 }
 644
 645 #ifdef GSSAPI
 646 int
 647 userauth_gssapi(Authctxt *authctxt)
 648 {
 649         Gssctxt *gssctxt = NULL;
 650         static gss_OID_set gss_supported = NULL;
 651         static u_int mech = 0;
 652         OM_uint32 min;
 653         int ok = 0;
 654         char *gss_host = NULL;
 655
 656         if (!options.gss_authentication) {
 657                 verbose("GSSAPI authentication disabled.");
 658                 return 0;
 659         }
 660
 661         if (options.gss_trust_dns)
 662                 gss_host = (char *)get_canonical_hostname(1);
 663         else
 664                 gss_host = (char *)authctxt->host;
 665
 666         /* Try one GSSAPI method at a time, rather than sending them all at
 667          * once. */
 668
 669         if (gss_supported == NULL)
 670                 if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) {
 671                         gss_supported = NULL;
 672                         return 0;
 673                 }
 674
 675         /* Check to see if the mechanism is usable before we offer it */
 676         while (mech < gss_supported->count && !ok) {
 677                 /* My DER encoding requires length<128 */
 678                 if (gss_supported->elements[mech].length < 128 &&
 679                     ssh_gssapi_check_mechanism(&gssctxt,
 680                     &gss_supported->elements[mech], gss_host,
 681                     options.gss_client_identity)) {
 682                         ok = 1; /* Mechanism works */
 683                 } else {
 684                         mech++;
 685                 }
 686         }
 687
 688         if (!ok)
 689                 return 0;
 690
 691         authctxt->methoddata=(void *)gssctxt;
 692
 693         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 694         packet_put_cstring(authctxt->server_user);
 695         packet_put_cstring(authctxt->service);
 696         packet_put_cstring(authctxt->method->name);
 697
 698         packet_put_int(1);
 699
 700         packet_put_int((gss_supported->elements[mech].length) + 2);
 701         packet_put_char(SSH_GSS_OIDTYPE);
 702         packet_put_char(gss_supported->elements[mech].length);
 703         packet_put_raw(gss_supported->elements[mech].elements,
 704             gss_supported->elements[mech].length);
 705
 706         packet_send();
 707
 708         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
 709         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
 710         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
 711         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
 712
 713         mech++; /* Move along to next candidate */
 714
 715         return 1;
 716 }
 717
 718 static OM_uint32
 719 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
 720 {
 721         Authctxt *authctxt = ctxt;
 722         Gssctxt *gssctxt = authctxt->methoddata;
 723         gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
 724         gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
 725         gss_buffer_desc gssbuf;
 726         OM_uint32 status, ms, flags;
 727         Buffer b;
 728
 729         status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
 730             recv_tok, &send_tok, &flags);
 731
 732         if (send_tok.length > 0) {
 733                 if (GSS_ERROR(status))
 734                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
 735                 else
 736                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
 737
 738                 packet_put_string(send_tok.value, send_tok.length);
 739                 packet_send();
 740                 gss_release_buffer(&ms, &send_tok);
 741         }
 742
 743         if (status == GSS_S_COMPLETE) {
 744                 /* send either complete or MIC, depending on mechanism */
 745                 if (strcmp(authctxt->method->name,"gssapi")==0 ||
 746                     (!(flags & GSS_C_INTEG_FLAG))) {
 747                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
 748                         packet_send();
 749                 } else {
 750                         ssh_gssapi_buildmic(&b, authctxt->server_user,
 751                             authctxt->service, "gssapi-with-mic");
 752
 753                         gssbuf.value = buffer_ptr(&b);
 754                         gssbuf.length = buffer_len(&b);
 755
 756                         status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
 757
 758                         if (!GSS_ERROR(status)) {
 759                                 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
 760                                 packet_put_string(mic.value, mic.length);
 761
 762                                 packet_send();
 763                         }
 764
 765                         buffer_free(&b);
 766                         gss_release_buffer(&ms, &mic);
 767                 }
 768         }
 769
 770         return status;
 771 }
 772
 773 /* ARGSUSED */
 774 void
 775 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
 776 {
 777         Authctxt *authctxt = ctxt;
 778         Gssctxt *gssctxt;
 779         u_int oidlen;
 780         u_char *oidv;
 781
 782         if (authctxt == NULL)
 783                 fatal("input_gssapi_response: no authentication context");
 784         gssctxt = authctxt->methoddata;
 785
 786         /* Setup our OID */
 787         oidv = packet_get_string(&oidlen);
 788
 789         if (oidlen <= 2 ||
 790             oidv[0] != SSH_GSS_OIDTYPE ||
 791             oidv[1] != oidlen - 2) {
 792                 xfree(oidv);
 793                 debug("Badly encoded mechanism OID received");
 794                 userauth(authctxt, NULL);
 795                 return;
 796         }
 797
 798         if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
 799                 fatal("Server returned different OID than expected");
 800
 801         packet_check_eom();
 802
 803         xfree(oidv);
 804
 805         if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
 806                 /* Start again with next method on list */
 807                 debug("Trying to start again");
 808                 userauth(authctxt, NULL);
 809                 return;
 810         }
 811 }
 812
 813 /* ARGSUSED */
 814 void
 815 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
 816 {
 817         Authctxt *authctxt = ctxt;
 818         gss_buffer_desc recv_tok;
 819         OM_uint32 status;
 820         u_int slen;
 821
 822         if (authctxt == NULL)
 823                 fatal("input_gssapi_response: no authentication context");
 824
 825         recv_tok.value = packet_get_string(&slen);
 826         recv_tok.length = slen; /* safe typecast */
 827
 828         packet_check_eom();
 829
 830         status = process_gssapi_token(ctxt, &recv_tok);
 831
 832         xfree(recv_tok.value);
 833
 834         if (GSS_ERROR(status)) {
 835                 /* Start again with the next method in the list */
 836                 userauth(authctxt, NULL);
 837                 return;
 838         }
 839 }
 840
 841 /* ARGSUSED */
 842 void
 843 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
 844 {
 845         Authctxt *authctxt = ctxt;
 846         Gssctxt *gssctxt;
 847         gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
 848         gss_buffer_desc recv_tok;
 849         OM_uint32 status, ms;
 850         u_int len;
 851
 852         if (authctxt == NULL)
 853                 fatal("input_gssapi_response: no authentication context");
 854         gssctxt = authctxt->methoddata;
 855
 856         recv_tok.value = packet_get_string(&len);
 857         recv_tok.length = len;
 858
 859         packet_check_eom();
 860
 861         /* Stick it into GSSAPI and see what it says */
 862         status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
 863             &recv_tok, &send_tok, NULL);
 864
 865         xfree(recv_tok.value);
 866         gss_release_buffer(&ms, &send_tok);
 867
 868         /* Server will be returning a failed packet after this one */
 869 }
 870
 871 /* ARGSUSED */
 872 void
 873 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
 874 {
 875         OM_uint32 maj, min;
 876         char *msg;
 877         char *lang;
 878
 879         maj=packet_get_int();
 880         min=packet_get_int();
 881         msg=packet_get_string(NULL);
 882         lang=packet_get_string(NULL);
 883
 884         packet_check_eom();
 885
 886         debug("Server GSSAPI Error:\n%s", msg);
 887         xfree(msg);
 888         xfree(lang);
 889 }
 890
 891 #ifdef GSI
 892 extern
 893 const gss_OID_desc * const              gss_mech_globus_gssapi_openssl;
 894 #define is_gsi_oid(oid) \
 895   (oid->length == gss_mech_globus_gssapi_openssl->length && \
 896    (memcmp(oid->elements, gss_mech_globus_gssapi_openssl->elements, \
 897            oid->length) == 0))
 898 #endif
 899
 900 int
 901 userauth_external(Authctxt *authctxt)
 902 {
 903     static int attempt = 0;
 904
 905     if (attempt++ >= 1)
 906         return 0;
 907
 908         /* The client MUST NOT try this method if initial key exchange
 909            was not performed using a GSSAPI-based key exchange
 910            method. */
 911         if (gss_kex_context == NULL) {
 912                 debug2("gsskex not performed, skipping external-keyx");
 913                 return 0;
 914         }
 915
 916     debug2("userauth_external");
 917     packet_start(SSH2_MSG_USERAUTH_REQUEST);
 918 #ifdef GSI
 919     if (options.implicit && is_gsi_oid(gss_kex_context->oid)) {
 920         packet_put_cstring("");
 921         } else {
 922 #endif
 923     packet_put_cstring(authctxt->server_user);
 924 #ifdef GSI
 925         }
 926 #endif
 927     packet_put_cstring(authctxt->service);
 928     packet_put_cstring(authctxt->method->name);
 929     packet_send();
 930     packet_write_wait();
 931     return 1;
 932 }
 933 int
 934 userauth_gsskeyex(Authctxt *authctxt)
 935 {
 936         Buffer b;
 937         gss_buffer_desc gssbuf;
 938         gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
 939         OM_uint32 ms;
 940
 941         static int attempt = 0;
 942         if (attempt++ >= 1)
 943                 return (0);
 944
 945         if (gss_kex_context == NULL) {
 946                 debug("No valid Key exchange context");
 947                 return (0);
 948         }
 949
 950 #ifdef GSI
 951     if (options.implicit && is_gsi_oid(gss_kex_context->oid)) {
 952         ssh_gssapi_buildmic(&b, "", authctxt->service, "gssapi-keyex");
 953         } else {
 954 #endif
 955         ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service,
 956                             "gssapi-keyex");
 957 #ifdef GSI
 958         }
 959 #endif
 960
 961         gssbuf.value = buffer_ptr(&b);
 962         gssbuf.length = buffer_len(&b);
 963
 964         if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) {
 965                 buffer_free(&b);
 966                 return (0);
 967         }
 968
 969         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 970 #ifdef GSI
 971     if (options.implicit && is_gsi_oid(gss_kex_context->oid)) {
 972         packet_put_cstring("");
 973         } else {
 974 #endif
 975         packet_put_cstring(authctxt->server_user);
 976 #ifdef GSI
 977         }
 978 #endif
 979         packet_put_cstring(authctxt->service);
 980         packet_put_cstring(authctxt->method->name);
 981         packet_put_string(mic.value, mic.length);
 982         packet_send();
 983
 984         buffer_free(&b);
 985         gss_release_buffer(&ms, &mic);
 986
 987         return (1);
 988 }
 989
 990 #endif /* GSSAPI */
 991
 992 int
 993 userauth_none(Authctxt *authctxt)
 994 {
 995         /* initial userauth request */
 996         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 997         packet_put_cstring(authctxt->server_user);
 998         packet_put_cstring(authctxt->service);
 999         packet_put_cstring(authctxt->method->name);
1000         packet_send();
1001         return 1;
1002 }
1003
1004 int
1005 userauth_passwd(Authctxt *authctxt)
1006 {
1007         static int attempt = 0;
1008         char prompt[150];
1009         char *password;
1010
1011         if (attempt++ >= options.number_of_password_prompts)
1012                 return 0;
1013
1014         if (attempt != 1)
1015                 error("Permission denied, please try again.");
1016
1017         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1018             authctxt->server_user, authctxt->host);
1019         password = read_passphrase(prompt, 0);
1020         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1021         packet_put_cstring(authctxt->server_user);
1022         packet_put_cstring(authctxt->service);
1023         packet_put_cstring(authctxt->method->name);
1024         packet_put_char(0);
1025         packet_put_cstring(password);
1026         memset(password, 0, strlen(password));
1027         xfree(password);
1028         packet_add_padding(64);
1029         packet_send();
1030
1031         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
1032             &input_userauth_passwd_changereq);
1033
1034         return 1;
1035 }
1036
1037 /*
1038  * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
1039  */
1040 /* ARGSUSED */
1041 void
1042 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
1043 {
1044         Authctxt *authctxt = ctxt;
1045         char *info, *lang, *password = NULL, *retype = NULL;
1046         char prompt[150];
1047
1048         debug2("input_userauth_passwd_changereq");
1049
1050         if (authctxt == NULL)
1051                 fatal("input_userauth_passwd_changereq: "
1052                     "no authentication context");
1053
1054         info = packet_get_string(NULL);
1055         lang = packet_get_string(NULL);
1056         if (strlen(info) > 0)
1057                 logit("%s", info);
1058         xfree(info);
1059         xfree(lang);
1060         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1061         packet_put_cstring(authctxt->server_user);
1062         packet_put_cstring(authctxt->service);
1063         packet_put_cstring(authctxt->method->name);
1064         packet_put_char(1);                     /* additional info */
1065         snprintf(prompt, sizeof(prompt),
1066             "Enter %.30s@%.128s's old password: ",
1067             authctxt->server_user, authctxt->host);
1068         password = read_passphrase(prompt, 0);
1069         packet_put_cstring(password);
1070         memset(password, 0, strlen(password));
1071         xfree(password);
1072         password = NULL;
1073         while (password == NULL) {
1074                 snprintf(prompt, sizeof(prompt),
1075                     "Enter %.30s@%.128s's new password: ",
1076                     authctxt->server_user, authctxt->host);
1077                 password = read_passphrase(prompt, RP_ALLOW_EOF);
1078                 if (password == NULL) {
1079                         /* bail out */
1080                         return;
1081                 }
1082                 snprintf(prompt, sizeof(prompt),
1083                     "Retype %.30s@%.128s's new password: ",
1084                     authctxt->server_user, authctxt->host);
1085                 retype = read_passphrase(prompt, 0);
1086                 if (strcmp(password, retype) != 0) {
1087                         memset(password, 0, strlen(password));
1088                         xfree(password);
1089                         logit("Mismatch; try again, EOF to quit.");
1090                         password = NULL;
1091                 }
1092                 memset(retype, 0, strlen(retype));
1093                 xfree(retype);
1094         }
1095         packet_put_cstring(password);
1096         memset(password, 0, strlen(password));
1097         xfree(password);
1098         packet_add_padding(64);
1099         packet_send();
1100
1101         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
1102             &input_userauth_passwd_changereq);
1103 }
1104
1105 #ifdef JPAKE
1106 static char *
1107 pw_encrypt(const char *password, const char *crypt_scheme, const char *salt)
1108 {
1109         /* OpenBSD crypt(3) handles all of these */
1110         if (strcmp(crypt_scheme, "crypt") == 0 ||
1111             strcmp(crypt_scheme, "bcrypt") == 0 ||
1112             strcmp(crypt_scheme, "md5crypt") == 0 ||
1113             strcmp(crypt_scheme, "crypt-extended") == 0)
1114                 return xstrdup(crypt(password, salt));
1115         error("%s: unsupported password encryption scheme \"%.100s\"",
1116             __func__, crypt_scheme);
1117         return NULL;
1118 }
1119
1120 static BIGNUM *
1121 jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme,
1122     const char *salt)
1123 {
1124         char prompt[256], *password, *crypted;
1125         u_char *secret;
1126         u_int secret_len;
1127         BIGNUM *ret;
1128
1129         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ",
1130             authctxt->server_user, authctxt->host);
1131         password = read_passphrase(prompt, 0);
1132
1133         if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) {
1134                 logit("Disabling %s authentication", authctxt->method->name);
1135                 authctxt->method->enabled = NULL;
1136                 /* Continue with an empty password to fail gracefully */
1137                 crypted = xstrdup("");
1138         }
1139
1140 #ifdef JPAKE_DEBUG
1141         debug3("%s: salt = %s", __func__, salt);
1142         debug3("%s: scheme = %s", __func__, crypt_scheme);
1143         debug3("%s: crypted = %s", __func__, crypted);
1144 #endif
1145
1146         if (hash_buffer(crypted, strlen(crypted), EVP_sha256(),
1147             &secret, &secret_len) != 0)
1148                 fatal("%s: hash_buffer", __func__);
1149
1150         bzero(password, strlen(password));
1151         bzero(crypted, strlen(crypted));
1152         xfree(password);
1153         xfree(crypted);
1154
1155         if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL)
1156                 fatal("%s: BN_bin2bn (secret)", __func__);
1157         bzero(secret, secret_len);
1158         xfree(secret);
1159
1160         return ret;
1161 }
1162
1163 /* ARGSUSED */
1164 void
1165 input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt)
1166 {
1167         Authctxt *authctxt = ctxt;
1168         struct jpake_ctx *pctx = authctxt->methoddata;
1169         u_char *x3_proof, *x4_proof, *x2_s_proof;
1170         u_int x3_proof_len, x4_proof_len, x2_s_proof_len;
1171         char *crypt_scheme, *salt;
1172
1173         /* Disable this message */
1174         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL);
1175
1176         if ((pctx->g_x3 = BN_new()) == NULL ||
1177             (pctx->g_x4 = BN_new()) == NULL)
1178                 fatal("%s: BN_new", __func__);
1179
1180         /* Fetch step 1 values */
1181         crypt_scheme = packet_get_string(NULL);
1182         salt = packet_get_string(NULL);
1183         pctx->server_id = packet_get_string(&pctx->server_id_len);
1184         packet_get_bignum2(pctx->g_x3);
1185         packet_get_bignum2(pctx->g_x4);
1186         x3_proof = packet_get_string(&x3_proof_len);
1187         x4_proof = packet_get_string(&x4_proof_len);
1188         packet_check_eom();
1189
1190         JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__));
1191
1192         /* Obtain password and derive secret */
1193         pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt);
1194         bzero(crypt_scheme, strlen(crypt_scheme));
1195         bzero(salt, strlen(salt));
1196         xfree(crypt_scheme);
1197         xfree(salt);
1198         JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__));
1199
1200         /* Calculate step 2 values */
1201         jpake_step2(pctx->grp, pctx->s, pctx->g_x1,
1202             pctx->g_x3, pctx->g_x4, pctx->x2,
1203             pctx->server_id, pctx->server_id_len,
1204             pctx->client_id, pctx->client_id_len,
1205             x3_proof, x3_proof_len,
1206             x4_proof, x4_proof_len,
1207             &pctx->a,
1208             &x2_s_proof, &x2_s_proof_len);
1209
1210         bzero(x3_proof, x3_proof_len);
1211         bzero(x4_proof, x4_proof_len);
1212         xfree(x3_proof);
1213         xfree(x4_proof);
1214
1215         JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__));
1216
1217         /* Send values for step 2 */
1218         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2);
1219         packet_put_bignum2(pctx->a);
1220         packet_put_string(x2_s_proof, x2_s_proof_len);
1221         packet_send();
1222
1223         bzero(x2_s_proof, x2_s_proof_len);
1224         xfree(x2_s_proof);
1225
1226         /* Expect step 2 packet from peer */
1227         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2,
1228             input_userauth_jpake_server_step2);
1229 }
1230
1231 /* ARGSUSED */
1232 void
1233 input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt)
1234 {
1235         Authctxt *authctxt = ctxt;
1236         struct jpake_ctx *pctx = authctxt->methoddata;
1237         u_char *x4_s_proof;
1238         u_int x4_s_proof_len;
1239
1240         /* Disable this message */
1241         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL);
1242
1243         if ((pctx->b = BN_new()) == NULL)
1244                 fatal("%s: BN_new", __func__);
1245
1246         /* Fetch step 2 values */
1247         packet_get_bignum2(pctx->b);
1248         x4_s_proof = packet_get_string(&x4_s_proof_len);
1249         packet_check_eom();
1250
1251         JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__));
1252
1253         /* Derive shared key and calculate confirmation hash */
1254         jpake_key_confirm(pctx->grp, pctx->s, pctx->b,
1255             pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4,
1256             pctx->client_id, pctx->client_id_len,
1257             pctx->server_id, pctx->server_id_len,
1258             session_id2, session_id2_len,
1259             x4_s_proof, x4_s_proof_len,
1260             &pctx->k,
1261             &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len);
1262
1263         bzero(x4_s_proof, x4_s_proof_len);
1264         xfree(x4_s_proof);
1265
1266         JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__));
1267
1268         /* Send key confirmation proof */
1269         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM);
1270         packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len);
1271         packet_send();
1272
1273         /* Expect confirmation from peer */
1274         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM,
1275             input_userauth_jpake_server_confirm);
1276 }
1277
1278 /* ARGSUSED */
1279 void
1280 input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt)
1281 {
1282         Authctxt *authctxt = ctxt;
1283         struct jpake_ctx *pctx = authctxt->methoddata;
1284
1285         /* Disable this message */
1286         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL);
1287
1288         pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len);
1289         packet_check_eom();
1290
1291         JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__));
1292
1293         /* Verify expected confirmation hash */
1294         if (jpake_check_confirm(pctx->k,
1295             pctx->server_id, pctx->server_id_len,
1296             session_id2, session_id2_len,
1297             pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1)
1298                 debug("%s: %s success", __func__, authctxt->method->name);
1299         else {
1300                 debug("%s: confirmation mismatch", __func__);
1301                 /* XXX stash this so if auth succeeds then we can warn/kill */
1302         }
1303
1304         userauth_jpake_cleanup(authctxt);
1305 }
1306 #endif /* JPAKE */
1307
1308 static int
1309 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
1310     u_char *data, u_int datalen)
1311 {
1312         Key *prv;
1313         int ret;
1314
1315         /* the agent supports this key */
1316         if (id->ac)
1317                 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
1318                     data, datalen));
1319         /*
1320          * we have already loaded the private key or
1321          * the private key is stored in external hardware
1322          */
1323         if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
1324                 return (key_sign(id->key, sigp, lenp, data, datalen));
1325         /* load the private key from the file */
1326         if ((prv = load_identity_file(id->filename)) == NULL)
1327                 return (-1);
1328         ret = key_sign(prv, sigp, lenp, data, datalen);
1329         key_free(prv);
1330         return (ret);
1331 }
1332
1333 static int
1334 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
1335 {
1336         Buffer b;
1337         u_char *blob, *signature;
1338         u_int bloblen, slen;
1339         u_int skip = 0;
1340         int ret = -1;
1341         int have_sig = 1;
1342
1343         debug3("sign_and_send_pubkey");
1344
1345         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1346                 /* we cannot handle this key */
1347                 debug3("sign_and_send_pubkey: cannot handle key");
1348                 return 0;
1349         }
1350         /* data to be signed */
1351         buffer_init(&b);
1352         if (datafellows & SSH_OLD_SESSIONID) {
1353                 buffer_append(&b, session_id2, session_id2_len);
1354                 skip = session_id2_len;
1355         } else {
1356                 buffer_put_string(&b, session_id2, session_id2_len);
1357                 skip = buffer_len(&b);
1358         }
1359         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1360         buffer_put_cstring(&b, authctxt->server_user);
1361         buffer_put_cstring(&b,
1362             datafellows & SSH_BUG_PKSERVICE ?
1363             "ssh-userauth" :
1364             authctxt->service);
1365         if (datafellows & SSH_BUG_PKAUTH) {
1366                 buffer_put_char(&b, have_sig);
1367         } else {
1368                 buffer_put_cstring(&b, authctxt->method->name);
1369                 buffer_put_char(&b, have_sig);
1370                 buffer_put_cstring(&b, key_ssh_name(id->key));
1371         }
1372         buffer_put_string(&b, blob, bloblen);
1373
1374         /* generate signature */
1375         ret = identity_sign(id, &signature, &slen,
1376             buffer_ptr(&b), buffer_len(&b));
1377         if (ret == -1) {
1378                 xfree(blob);
1379                 buffer_free(&b);
1380                 return 0;
1381         }
1382 #ifdef DEBUG_PK
1383         buffer_dump(&b);
1384 #endif
1385         if (datafellows & SSH_BUG_PKSERVICE) {
1386                 buffer_clear(&b);
1387                 buffer_append(&b, session_id2, session_id2_len);
1388                 skip = session_id2_len;
1389                 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1390                 buffer_put_cstring(&b, authctxt->server_user);
1391                 buffer_put_cstring(&b, authctxt->service);
1392                 buffer_put_cstring(&b, authctxt->method->name);
1393                 buffer_put_char(&b, have_sig);
1394                 if (!(datafellows & SSH_BUG_PKAUTH))
1395                         buffer_put_cstring(&b, key_ssh_name(id->key));
1396                 buffer_put_string(&b, blob, bloblen);
1397         }
1398         xfree(blob);
1399
1400         /* append signature */
1401         buffer_put_string(&b, signature, slen);
1402         xfree(signature);
1403
1404         /* skip session id and packet type */
1405         if (buffer_len(&b) < skip + 1)
1406                 fatal("userauth_pubkey: internal error");
1407         buffer_consume(&b, skip + 1);
1408
1409         /* put remaining data from buffer into packet */
1410         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1411         packet_put_raw(buffer_ptr(&b), buffer_len(&b));
1412         buffer_free(&b);
1413         packet_send();
1414
1415         return 1;
1416 }
1417
1418 static int
1419 send_pubkey_test(Authctxt *authctxt, Identity *id)
1420 {
1421         u_char *blob;
1422         u_int bloblen, have_sig = 0;
1423
1424         debug3("send_pubkey_test");
1425
1426         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1427                 /* we cannot handle this key */
1428                 debug3("send_pubkey_test: cannot handle key");
1429                 return 0;
1430         }
1431         /* register callback for USERAUTH_PK_OK message */
1432         dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
1433
1434         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1435         packet_put_cstring(authctxt->server_user);
1436         packet_put_cstring(authctxt->service);
1437         packet_put_cstring(authctxt->method->name);
1438         packet_put_char(have_sig);
1439         if (!(datafellows & SSH_BUG_PKAUTH))
1440                 packet_put_cstring(key_ssh_name(id->key));
1441         packet_put_string(blob, bloblen);
1442         xfree(blob);
1443         packet_send();
1444         return 1;
1445 }
1446
1447 static Key *
1448 load_identity_file(char *filename)
1449 {
1450         Key *private;
1451         char prompt[300], *passphrase;
1452         int perm_ok, quit, i;
1453         struct stat st;
1454
1455         if (stat(filename, &st) < 0) {
1456                 debug3("no such identity: %s", filename);
1457                 return NULL;
1458         }
1459         private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
1460         if (!perm_ok)
1461                 return NULL;
1462         if (private == NULL) {
1463                 if (options.batch_mode)
1464                         return NULL;
1465                 snprintf(prompt, sizeof prompt,
1466                     "Enter passphrase for key '%.100s': ", filename);
1467                 for (i = 0; i < options.number_of_password_prompts; i++) {
1468                         passphrase = read_passphrase(prompt, 0);
1469                         if (strcmp(passphrase, "") != 0) {
1470                                 private = key_load_private_type(KEY_UNSPEC,
1471                                     filename, passphrase, NULL, NULL);
1472                                 quit = 0;
1473                         } else {
1474                                 debug2("no passphrase given, try next key");
1475                                 quit = 1;
1476                         }
1477                         memset(passphrase, 0, strlen(passphrase));
1478                         xfree(passphrase);
1479                         if (private != NULL || quit)
1480                                 break;
1481                         debug2("bad passphrase given, try again...");
1482                 }
1483         }
1484         return private;
1485 }
1486
1487 /*
1488  * try keys in the following order:
1489  *      1. agent keys that are found in the config file
1490  *      2. other agent keys
1491  *      3. keys that are only listed in the config file
1492  */
1493 static void
1494 pubkey_prepare(Authctxt *authctxt)
1495 {
1496         Identity *id;
1497         Idlist agent, files, *preferred;
1498         Key *key;
1499         AuthenticationConnection *ac;
1500         char *comment;
1501         int i, found;
1502
1503         TAILQ_INIT(&agent);     /* keys from the agent */
1504         TAILQ_INIT(&files);     /* keys from the config file */
1505         preferred = &authctxt->keys;
1506         TAILQ_INIT(preferred);  /* preferred order of keys */
1507
1508         /* list of keys stored in the filesystem */
1509         for (i = 0; i < options.num_identity_files; i++) {
1510                 key = options.identity_keys[i];
1511                 if (key && key->type == KEY_RSA1)
1512                         continue;
1513                 options.identity_keys[i] = NULL;
1514                 id = xcalloc(1, sizeof(*id));
1515                 id->key = key;
1516                 id->filename = xstrdup(options.identity_files[i]);
1517                 TAILQ_INSERT_TAIL(&files, id, next);
1518         }
1519         /* list of keys supported by the agent */
1520         if ((ac = ssh_get_authentication_connection())) {
1521                 for (key = ssh_get_first_identity(ac, &comment, 2);
1522                     key != NULL;
1523                     key = ssh_get_next_identity(ac, &comment, 2)) {
1524                         found = 0;
1525                         TAILQ_FOREACH(id, &files, next) {
1526                                 /* agent keys from the config file are preferred */
1527                                 if (key_equal(key, id->key)) {
1528                                         key_free(key);
1529                                         xfree(comment);
1530                                         TAILQ_REMOVE(&files, id, next);
1531                                         TAILQ_INSERT_TAIL(preferred, id, next);
1532                                         id->ac = ac;
1533                                         found = 1;
1534                                         break;
1535                                 }
1536                         }
1537                         if (!found && !options.identities_only) {
1538                                 id = xcalloc(1, sizeof(*id));
1539                                 id->key = key;
1540                                 id->filename = comment;
1541                                 id->ac = ac;
1542                                 TAILQ_INSERT_TAIL(&agent, id, next);
1543                         }
1544                 }
1545                 /* append remaining agent keys */
1546                 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1547                         TAILQ_REMOVE(&agent, id, next);
1548                         TAILQ_INSERT_TAIL(preferred, id, next);
1549                 }
1550                 authctxt->agent = ac;
1551         }
1552         /* append remaining keys from the config file */
1553         for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1554                 TAILQ_REMOVE(&files, id, next);
1555                 TAILQ_INSERT_TAIL(preferred, id, next);
1556         }
1557         TAILQ_FOREACH(id, preferred, next) {
1558                 debug2("key: %s (%p)", id->filename, id->key);
1559         }
1560 }
1561
1562 static void
1563 pubkey_cleanup(Authctxt *authctxt)
1564 {
1565         Identity *id;
1566
1567         if (authctxt->agent != NULL)
1568                 ssh_close_authentication_connection(authctxt->agent);
1569         for (id = TAILQ_FIRST(&authctxt->keys); id;
1570             id = TAILQ_FIRST(&authctxt->keys)) {
1571                 TAILQ_REMOVE(&authctxt->keys, id, next);
1572                 if (id->key)
1573                         key_free(id->key);
1574                 if (id->filename)
1575                         xfree(id->filename);
1576                 xfree(id);
1577         }
1578 }
1579
1580 int
1581 userauth_pubkey(Authctxt *authctxt)
1582 {
1583         Identity *id;
1584         int sent = 0;
1585
1586         while ((id = TAILQ_FIRST(&authctxt->keys))) {
1587                 if (id->tried++)
1588                         return (0);
1589                 /* move key to the end of the queue */
1590                 TAILQ_REMOVE(&authctxt->keys, id, next);
1591                 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1592                 /*
1593                  * send a test message if we have the public key. for
1594                  * encrypted keys we cannot do this and have to load the
1595                  * private key instead
1596                  */
1597                 if (id->key && id->key->type != KEY_RSA1) {
1598                         debug("Offering public key: %s", id->filename);
1599                         sent = send_pubkey_test(authctxt, id);
1600                 } else if (id->key == NULL) {
1601                         debug("Trying private key: %s", id->filename);
1602                         id->key = load_identity_file(id->filename);
1603                         if (id->key != NULL) {
1604                                 id->isprivate = 1;
1605                                 sent = sign_and_send_pubkey(authctxt, id);
1606                                 key_free(id->key);
1607                                 id->key = NULL;
1608                         }
1609                 }
1610                 if (sent)
1611                         return (sent);
1612         }
1613         return (0);
1614 }
1615
1616 /*
1617  * Send userauth request message specifying keyboard-interactive method.
1618  */
1619 int
1620 userauth_kbdint(Authctxt *authctxt)
1621 {
1622         static int attempt = 0;
1623
1624         if (attempt++ >= options.number_of_password_prompts)
1625                 return 0;
1626         /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1627         if (attempt > 1 && !authctxt->info_req_seen) {
1628                 debug3("userauth_kbdint: disable: no info_req_seen");
1629                 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1630                 return 0;
1631         }
1632
1633         debug2("userauth_kbdint");
1634         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1635         packet_put_cstring(authctxt->server_user);
1636         packet_put_cstring(authctxt->service);
1637         packet_put_cstring(authctxt->method->name);
1638         packet_put_cstring("");                                 /* lang */
1639         packet_put_cstring(options.kbd_interactive_devices ?
1640             options.kbd_interactive_devices : "");
1641         packet_send();
1642
1643         dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1644         return 1;
1645 }
1646
1647 /*
1648  * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1649  */
1650 void
1651 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1652 {
1653         Authctxt *authctxt = ctxt;
1654         char *name, *inst, *lang, *prompt, *response;
1655         u_int num_prompts, i;
1656         int echo = 0;
1657
1658         debug2("input_userauth_info_req");
1659
1660         if (authctxt == NULL)
1661                 fatal("input_userauth_info_req: no authentication context");
1662
1663         authctxt->info_req_seen = 1;
1664
1665         name = packet_get_string(NULL);
1666         inst = packet_get_string(NULL);
1667         lang = packet_get_string(NULL);
1668         if (strlen(name) > 0)
1669                 logit("%s", name);
1670         if (strlen(inst) > 0)
1671                 logit("%s", inst);
1672         xfree(name);
1673         xfree(inst);
1674         xfree(lang);
1675
1676         num_prompts = packet_get_int();
1677         /*
1678          * Begin to build info response packet based on prompts requested.
1679          * We commit to providing the correct number of responses, so if
1680          * further on we run into a problem that prevents this, we have to
1681          * be sure and clean this up and send a correct error response.
1682          */
1683         packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1684         packet_put_int(num_prompts);
1685
1686         debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1687         for (i = 0; i < num_prompts; i++) {
1688                 prompt = packet_get_string(NULL);
1689                 echo = packet_get_char();
1690
1691                 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1692
1693                 packet_put_cstring(response);
1694                 memset(response, 0, strlen(response));
1695                 xfree(response);
1696                 xfree(prompt);
1697         }
1698         packet_check_eom(); /* done with parsing incoming message. */
1699
1700         packet_add_padding(64);
1701         packet_send();
1702 }
1703
1704 static int
1705 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1706     u_char *data, u_int datalen)
1707 {
1708         Buffer b;
1709         struct stat st;
1710         pid_t pid;
1711         int to[2], from[2], status, version = 2;
1712
1713         debug2("ssh_keysign called");
1714
1715         if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1716                 error("ssh_keysign: no installed: %s", strerror(errno));
1717                 return -1;
1718         }
1719         if (fflush(stdout) != 0)
1720                 error("ssh_keysign: fflush: %s", strerror(errno));
1721         if (pipe(to) < 0) {
1722                 error("ssh_keysign: pipe: %s", strerror(errno));
1723                 return -1;
1724         }
1725         if (pipe(from) < 0) {
1726                 error("ssh_keysign: pipe: %s", strerror(errno));
1727                 return -1;
1728         }
1729         if ((pid = fork()) < 0) {
1730                 error("ssh_keysign: fork: %s", strerror(errno));
1731                 return -1;
1732         }
1733         if (pid == 0) {
1734                 permanently_drop_suid(getuid());
1735                 close(from[0]);
1736                 if (dup2(from[1], STDOUT_FILENO) < 0)
1737                         fatal("ssh_keysign: dup2: %s", strerror(errno));
1738                 close(to[1]);
1739                 if (dup2(to[0], STDIN_FILENO) < 0)
1740                         fatal("ssh_keysign: dup2: %s", strerror(errno));
1741                 close(from[1]);
1742                 close(to[0]);
1743                 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1744                 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1745                     strerror(errno));
1746         }
1747         close(from[1]);
1748         close(to[0]);
1749
1750         buffer_init(&b);
1751         buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1752         buffer_put_string(&b, data, datalen);
1753         if (ssh_msg_send(to[1], version, &b) == -1)
1754                 fatal("ssh_keysign: couldn't send request");
1755
1756         if (ssh_msg_recv(from[0], &b) < 0) {
1757                 error("ssh_keysign: no reply");
1758                 buffer_free(&b);
1759                 return -1;
1760         }
1761         close(from[0]);
1762         close(to[1]);
1763
1764         while (waitpid(pid, &status, 0) < 0)
1765                 if (errno != EINTR)
1766                         break;
1767
1768         if (buffer_get_char(&b) != version) {
1769                 error("ssh_keysign: bad version");
1770                 buffer_free(&b);
1771                 return -1;
1772         }
1773         *sigp = buffer_get_string(&b, lenp);
1774         buffer_free(&b);
1775
1776         return 0;
1777 }
1778
1779 int
1780 userauth_hostbased(Authctxt *authctxt)
1781 {
1782         Key *private = NULL;
1783         Sensitive *sensitive = authctxt->sensitive;
1784         Buffer b;
1785         u_char *signature, *blob;
1786         char *chost, *pkalg, *p, myname[NI_MAXHOST];
1787         const char *service;
1788         u_int blen, slen;
1789         int ok, i, len, found = 0;
1790
1791         /* check for a useful key */
1792         for (i = 0; i < sensitive->nkeys; i++) {
1793                 private = sensitive->keys[i];
1794                 if (private && private->type != KEY_RSA1) {
1795                         found = 1;
1796                         /* we take and free the key */
1797                         sensitive->keys[i] = NULL;
1798                         break;
1799                 }
1800         }
1801         if (!found) {
1802                 debug("No more client hostkeys for hostbased authentication.");
1803                 return 0;
1804         }
1805         if (key_to_blob(private, &blob, &blen) == 0) {
1806                 key_free(private);
1807                 return 0;
1808         }
1809         /* figure out a name for the client host */
1810         p = NULL;
1811         if (packet_connection_is_on_socket())
1812                 p = get_local_name(packet_get_connection_in());
1813         if (p == NULL) {
1814                 if (gethostname(myname, sizeof(myname)) == -1) {
1815                         verbose("userauth_hostbased: gethostname: %s",
1816                             strerror(errno));
1817                 } else
1818                         p = xstrdup(myname);
1819         }
1820         if (p == NULL) {
1821                 error("userauth_hostbased: cannot get local ipaddr/name");
1822                 key_free(private);
1823                 xfree(blob);
1824                 return 0;
1825         }
1826         len = strlen(p) + 2;
1827         xasprintf(&chost, "%s.", p);
1828         debug2("userauth_hostbased: chost %s", chost);
1829         xfree(p);
1830
1831         service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1832             authctxt->service;
1833         pkalg = xstrdup(key_ssh_name(private));
1834         buffer_init(&b);
1835         /* construct data */
1836         buffer_put_string(&b, session_id2, session_id2_len);
1837         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1838         buffer_put_cstring(&b, authctxt->server_user);
1839         buffer_put_cstring(&b, service);
1840         buffer_put_cstring(&b, authctxt->method->name);
1841         buffer_put_cstring(&b, pkalg);
1842         buffer_put_string(&b, blob, blen);
1843         buffer_put_cstring(&b, chost);
1844         buffer_put_cstring(&b, authctxt->local_user);
1845 #ifdef DEBUG_PK
1846         buffer_dump(&b);
1847 #endif
1848         if (sensitive->external_keysign)
1849                 ok = ssh_keysign(private, &signature, &slen,
1850                     buffer_ptr(&b), buffer_len(&b));
1851         else
1852                 ok = key_sign(private, &signature, &slen,
1853                     buffer_ptr(&b), buffer_len(&b));
1854         key_free(private);
1855         buffer_free(&b);
1856         if (ok != 0) {
1857                 error("key_sign failed");
1858                 xfree(chost);
1859                 xfree(pkalg);
1860                 xfree(blob);
1861                 return 0;
1862         }
1863         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1864         packet_put_cstring(authctxt->server_user);
1865         packet_put_cstring(authctxt->service);
1866         packet_put_cstring(authctxt->method->name);
1867         packet_put_cstring(pkalg);
1868         packet_put_string(blob, blen);
1869         packet_put_cstring(chost);
1870         packet_put_cstring(authctxt->local_user);
1871         packet_put_string(signature, slen);
1872         memset(signature, 's', slen);
1873         xfree(signature);
1874         xfree(chost);
1875         xfree(pkalg);
1876         xfree(blob);
1877
1878         packet_send();
1879         return 1;
1880 }
1881
1882 #ifdef JPAKE
1883 int
1884 userauth_jpake(Authctxt *authctxt)
1885 {
1886         struct jpake_ctx *pctx;
1887         u_char *x1_proof, *x2_proof;
1888         u_int x1_proof_len, x2_proof_len;
1889         static int attempt = 0; /* XXX share with userauth_password's? */
1890
1891         if (attempt++ >= options.number_of_password_prompts)
1892                 return 0;
1893         if (attempt != 1)
1894                 error("Permission denied, please try again.");
1895
1896         if (authctxt->methoddata != NULL)
1897                 fatal("%s: authctxt->methoddata already set (%p)",
1898                     __func__, authctxt->methoddata);
1899
1900         authctxt->methoddata = pctx = jpake_new();
1901
1902         /*
1903          * Send request immediately, to get the protocol going while
1904          * we do the initial computations.
1905          */
1906         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1907         packet_put_cstring(authctxt->server_user);
1908         packet_put_cstring(authctxt->service);
1909         packet_put_cstring(authctxt->method->name);
1910         packet_send();
1911         packet_write_wait();
1912
1913         jpake_step1(pctx->grp,
1914             &pctx->client_id, &pctx->client_id_len,
1915             &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2,
1916             &x1_proof, &x1_proof_len,
1917             &x2_proof, &x2_proof_len);
1918
1919         JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__));
1920
1921         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1);
1922         packet_put_string(pctx->client_id, pctx->client_id_len);
1923         packet_put_bignum2(pctx->g_x1);
1924         packet_put_bignum2(pctx->g_x2);
1925         packet_put_string(x1_proof, x1_proof_len);
1926         packet_put_string(x2_proof, x2_proof_len);
1927         packet_send();
1928
1929         bzero(x1_proof, x1_proof_len);
1930         bzero(x2_proof, x2_proof_len);
1931         xfree(x1_proof);
1932         xfree(x2_proof);
1933
1934         /* Expect step 1 packet from peer */
1935         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1,
1936             input_userauth_jpake_server_step1);
1937
1938         return 1;
1939 }
1940
1941 void
1942 userauth_jpake_cleanup(Authctxt *authctxt)
1943 {
1944         debug3("%s: clean up", __func__);
1945         if (authctxt->methoddata != NULL) {
1946                 jpake_free(authctxt->methoddata);
1947                 authctxt->methoddata = NULL;
1948         }
1949 }
1950 #endif /* JPAKE */
1951
1952 /* find auth method */
1953
1954 /*
1955  * given auth method name, if configurable options permit this method fill
1956  * in auth_ident field and return true, otherwise return false.
1957  */
1958 static int
1959 authmethod_is_enabled(Authmethod *method)
1960 {
1961         if (method == NULL)
1962                 return 0;
1963         /* return false if options indicate this method is disabled */
1964         if  (method->enabled == NULL || *method->enabled == 0)
1965                 return 0;
1966         /* return false if batch mode is enabled but method needs interactive mode */
1967         if  (method->batch_flag != NULL && *method->batch_flag != 0)
1968                 return 0;
1969         return 1;
1970 }
1971
1972 static Authmethod *
1973 authmethod_lookup(const char *name)
1974 {
1975         Authmethod *method = NULL;
1976         if (name != NULL)
1977                 for (method = authmethods; method->name != NULL; method++)
1978                         if (strcmp(name, method->name) == 0)
1979                                 return method;
1980         debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1981         return NULL;
1982 }
1983
1984 /* XXX internal state */
1985 static Authmethod *current = NULL;
1986 static char *supported = NULL;
1987 static char *preferred = NULL;
1988
1989 /*
1990  * Given the authentication method list sent by the server, return the
1991  * next method we should try.  If the server initially sends a nil list,
1992  * use a built-in default list.
1993  */
1994 static Authmethod *
1995 authmethod_get(char *authlist)
1996 {
1997         char *name = NULL;
1998         u_int next;
1999
2000         /* Use a suitable default if we're passed a nil list.  */
2001         if (authlist == NULL || strlen(authlist) == 0)
2002                 authlist = options.preferred_authentications;
2003
2004         if (supported == NULL || strcmp(authlist, supported) != 0) {
2005                 debug3("start over, passed a different list %s", authlist);
2006                 if (supported != NULL)
2007                         xfree(supported);
2008                 supported = xstrdup(authlist);
2009                 preferred = options.preferred_authentications;
2010                 debug3("preferred %s", preferred);
2011                 current = NULL;
2012         } else if (current != NULL && authmethod_is_enabled(current))
2013                 return current;
2014
2015         for (;;) {
2016                 if ((name = match_list(preferred, supported, &next)) == NULL) {
2017                         debug("No more authentication methods to try.");
2018                         current = NULL;
2019                         return NULL;
2020                 }
2021                 preferred += next;
2022                 debug3("authmethod_lookup %s", name);
2023                 debug3("remaining preferred: %s", preferred);
2024                 if ((current = authmethod_lookup(name)) != NULL &&
2025                     authmethod_is_enabled(current)) {
2026                         debug3("authmethod_is_enabled %s", name);
2027                         debug("Next authentication method: %s", name);
2028                         return current;
2029                 }
2030         }
2031 }
2032
2033 static char *
2034 authmethods_get(void)
2035 {
2036         Authmethod *method = NULL;
2037         Buffer b;
2038         char *list;
2039
2040         buffer_init(&b);
2041         for (method = authmethods; method->name != NULL; method++) {
2042                 if (authmethod_is_enabled(method)) {
2043                         if (buffer_len(&b) > 0)
2044                                 buffer_append(&b, ",", 1);
2045                         buffer_append(&b, method->name, strlen(method->name));
2046                 }
2047         }
2048         buffer_append(&b, "\0", 1);
2049         list = xstrdup(buffer_ptr(&b));
2050         buffer_free(&b);
2051         return list;
2052 }
2053