openssh/sshconnect2.c

   1 /* $OpenBSD: sshconnect2.c,v 1.170 2008/11/04 08:22:13 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 "jpake.h"
  72
  73 #ifdef GSSAPI
  74 #include "ssh-gss.h"
  75 #endif
  76
  77 /* import */
  78 extern char *client_version_string;
  79 extern char *server_version_string;
  80 extern Options options;
  81 extern Kex *xxx_kex;
  82
  83 /* tty_flag is set in ssh.c. use this in ssh_userauth2 */
  84 /* if it is set then prevent the switch to the null cipher */
  85
  86 extern int tty_flag;
  87
  88 /* tty_flag is set in ssh.c. use this in ssh_userauth2 */
  89 /* if it is set then prevent the switch to the null cipher */
  90
  91 extern int tty_flag;
  92
  93 /* tty_flag is set in ssh.c. use this in ssh_userauth2 */
  94 /* if it is set then prevent the switch to the null cipher */
  95
  96 extern int tty_flag;
  97
  98 /*
  99  * SSH2 key exchange
 100  */
 101
 102 u_char *session_id2 = NULL;
 103 u_int session_id2_len = 0;
 104
 105 char *xxx_host;
 106 struct sockaddr *xxx_hostaddr;
 107
 108 Kex *xxx_kex = NULL;
 109
 110 static int
 111 verify_host_key_callback(Key *hostkey)
 112 {
 113         if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
 114                 fatal("Host key verification failed.");
 115         return 0;
 116 }
 117
 118 void
 119 ssh_kex2(char *host, struct sockaddr *hostaddr)
 120 {
 121         Kex *kex;
 122
 123 #ifdef GSSAPI
 124         char *orig = NULL, *gss = NULL;
 125         char *gss_host = NULL;
 126 #endif
 127
 128         xxx_host = host;
 129         xxx_hostaddr = hostaddr;
 130
 131 #ifdef GSSAPI
 132         if (options.gss_keyex) {
 133                 /* Add the GSSAPI mechanisms currently supported on this
 134                  * client to the key exchange algorithm proposal */
 135                 orig = myproposal[PROPOSAL_KEX_ALGS];
 136
 137                 if (options.gss_trust_dns)
 138                         gss_host = (char *)get_canonical_hostname(1);
 139                 else
 140                         gss_host = host;
 141
 142                 gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity);
 143                 if (gss) {
 144                         debug("Offering GSSAPI proposal: %s", gss);
 145                         xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
 146                             "%s,%s", gss, orig);
 147                 }
 148         }
 149 #endif
 150
 151         if (options.ciphers == (char *)-1) {
 152                 logit("No valid ciphers for protocol version 2 given, using defaults.");
 153                 options.ciphers = NULL;
 154         }
 155         if (options.ciphers != NULL) {
 156                 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 157                 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
 158         }
 159         myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 160             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
 161         myproposal[PROPOSAL_ENC_ALGS_STOC] =
 162             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
 163         if (options.compression) {
 164                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 165                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
 166         } else {
 167                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 168                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
 169         }
 170         if (options.macs != NULL) {
 171                 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
 172                 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
 173         }
 174         if (options.hostkeyalgorithms != NULL)
 175                 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
 176                     options.hostkeyalgorithms;
 177
 178 #ifdef GSSAPI
 179         /* If we've got GSSAPI algorithms, then we also support the
 180          * 'null' hostkey, as a last resort */
 181         if (options.gss_keyex && gss) {
 182                 orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
 183                 xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],
 184                     "%s,null", orig);
 185                 xfree(gss);
 186         }
 187 #endif
 188
 189         if (options.rekey_limit)
 190                 packet_set_rekey_limit((u_int32_t)options.rekey_limit);
 191
 192         /* start key exchange */
 193         kex = kex_setup(myproposal);
 194         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
 195         kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
 196         kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
 197         kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
 198 #ifdef GSSAPI
 199         if (options.gss_keyex) {
 200                 kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
 201                 kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client;
 202                 kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client;
 203         }
 204 #endif
 205         kex->client_version_string=client_version_string;
 206         kex->server_version_string=server_version_string;
 207         kex->verify_host_key=&verify_host_key_callback;
 208
 209 #ifdef GSSAPI
 210         if (options.gss_keyex) {
 211                 kex->gss_deleg_creds = options.gss_deleg_creds;
 212                 kex->gss_trust_dns = options.gss_trust_dns;
 213                 kex->gss_client = options.gss_client_identity;
 214                 kex->gss_host = gss_host;
 215         }
 216 #endif
 217
 218         xxx_kex = kex;
 219
 220         dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
 221
 222         session_id2 = kex->session_id;
 223         session_id2_len = kex->session_id_len;
 224
 225 #ifdef DEBUG_KEXDH
 226         /* send 1st encrypted/maced/compressed message */
 227         packet_start(SSH2_MSG_IGNORE);
 228         packet_put_cstring("markus");
 229         packet_send();
 230         packet_write_wait();
 231 #endif
 232 }
 233
 234 /*
 235  * Authenticate user
 236  */
 237
 238 typedef struct Authctxt Authctxt;
 239 typedef struct Authmethod Authmethod;
 240 typedef struct identity Identity;
 241 typedef struct idlist Idlist;
 242
 243 struct identity {
 244         TAILQ_ENTRY(identity) next;
 245         AuthenticationConnection *ac;   /* set if agent supports key */
 246         Key     *key;                   /* public/private key */
 247         char    *filename;              /* comment for agent-only keys */
 248         int     tried;
 249         int     isprivate;              /* key points to the private key */
 250 };
 251 TAILQ_HEAD(idlist, identity);
 252
 253 struct Authctxt {
 254         const char *server_user;
 255         const char *local_user;
 256         const char *host;
 257         const char *service;
 258         Authmethod *method;
 259         int success;
 260         char *authlist;
 261         /* pubkey */
 262         Idlist keys;
 263         AuthenticationConnection *agent;
 264         /* hostbased */
 265         Sensitive *sensitive;
 266         /* kbd-interactive */
 267         int info_req_seen;
 268         /* generic */
 269         void *methoddata;
 270 };
 271 struct Authmethod {
 272         char    *name;          /* string to compare against server's list */
 273         int     (*userauth)(Authctxt *authctxt);
 274         void    (*cleanup)(Authctxt *authctxt);
 275         int     *enabled;       /* flag in option struct that enables method */
 276         int     *batch_flag;    /* flag in option struct that disables method */
 277 };
 278
 279 void    input_userauth_success(int, u_int32_t, void *);
 280 void    input_userauth_failure(int, u_int32_t, void *);
 281 void    input_userauth_banner(int, u_int32_t, void *);
 282 void    input_userauth_error(int, u_int32_t, void *);
 283 void    input_userauth_info_req(int, u_int32_t, void *);
 284 void    input_userauth_pk_ok(int, u_int32_t, void *);
 285 void    input_userauth_passwd_changereq(int, u_int32_t, void *);
 286 void    input_userauth_jpake_server_step1(int, u_int32_t, void *);
 287 void    input_userauth_jpake_server_step2(int, u_int32_t, void *);
 288 void    input_userauth_jpake_server_confirm(int, u_int32_t, void *);
 289
 290 int     userauth_none(Authctxt *);
 291 int     userauth_pubkey(Authctxt *);
 292 int     userauth_passwd(Authctxt *);
 293 int     userauth_kbdint(Authctxt *);
 294 int     userauth_hostbased(Authctxt *);
 295 int     userauth_jpake(Authctxt *);
 296
 297 void    userauth_jpake_cleanup(Authctxt *);
 298
 299 #ifdef GSSAPI
 300 int     userauth_external(Authctxt *authctxt);
 301 int     userauth_gssapi(Authctxt *authctxt);
 302 int     userauth_gssapi_with_mic(Authctxt *authctxt);
 303 int     userauth_gssapi_without_mic(Authctxt *authctxt);
 304 void    input_gssapi_response(int type, u_int32_t, void *);
 305 void    input_gssapi_token(int type, u_int32_t, void *);
 306 void    input_gssapi_hash(int type, u_int32_t, void *);
 307 void    input_gssapi_error(int, u_int32_t, void *);
 308 void    input_gssapi_errtok(int, u_int32_t, void *);
 309 int     userauth_gsskeyex(Authctxt *authctxt);
 310 #endif
 311
 312 void    userauth(Authctxt *, char *);
 313
 314 static int sign_and_send_pubkey(Authctxt *, Identity *);
 315 static void pubkey_prepare(Authctxt *);
 316 static void pubkey_cleanup(Authctxt *);
 317 static Key *load_identity_file(char *);
 318
 319 static Authmethod *authmethod_get(char *authlist);
 320 static Authmethod *authmethod_lookup(const char *name);
 321 static char *authmethods_get(void);
 322
 323 Authmethod authmethods[] = {
 324 #ifdef GSSAPI
 325         {"gssapi-keyex",
 326                 userauth_gsskeyex,
 327                 NULL,
 328                 &options.gss_authentication,
 329                 NULL},
 330         {"external-keyx",
 331                 userauth_external,
 332                 NULL,
 333                 &options.gss_authentication,
 334                 NULL},
 335         {"gssapi-with-mic",
 336                 userauth_gssapi,
 337                 NULL,
 338                 &options.gss_authentication,
 339                 NULL},
 340         {"gssapi",
 341                 userauth_gssapi,
 342                 NULL,
 343                 &options.gss_authentication,
 344                 NULL},
 345 #endif
 346         {"hostbased",
 347                 userauth_hostbased,
 348                 NULL,
 349                 &options.hostbased_authentication,
 350                 NULL},
 351         {"publickey",
 352                 userauth_pubkey,
 353                 NULL,
 354                 &options.pubkey_authentication,
 355                 NULL},
 356 #ifdef JPAKE
 357         {"jpake-01@openssh.com",
 358                 userauth_jpake,
 359                 userauth_jpake_cleanup,
 360                 &options.zero_knowledge_password_authentication,
 361                 &options.batch_mode},
 362 #endif
 363         {"keyboard-interactive",
 364                 userauth_kbdint,
 365                 NULL,
 366                 &options.kbd_interactive_authentication,
 367                 &options.batch_mode},
 368         {"password",
 369                 userauth_passwd,
 370                 NULL,
 371                 &options.password_authentication,
 372                 &options.batch_mode},
 373         {"none",
 374                 userauth_none,
 375                 NULL,
 376                 NULL,
 377                 NULL},
 378         {NULL, NULL, NULL, NULL, NULL}
 379 };
 380
 381 void
 382 ssh_userauth2(const char *local_user, const char *server_user, char *host,
 383     Sensitive *sensitive)
 384 {
 385         Authctxt authctxt;
 386         int type;
 387
 388         if (options.challenge_response_authentication)
 389                 options.kbd_interactive_authentication = 1;
 390
 391         packet_start(SSH2_MSG_SERVICE_REQUEST);
 392         packet_put_cstring("ssh-userauth");
 393         packet_send();
 394         debug("SSH2_MSG_SERVICE_REQUEST sent");
 395         packet_write_wait();
 396         type = packet_read();
 397         if (type != SSH2_MSG_SERVICE_ACCEPT)
 398                 fatal("Server denied authentication request: %d", type);
 399         if (packet_remaining() > 0) {
 400                 char *reply = packet_get_string(NULL);
 401                 debug2("service_accept: %s", reply);
 402                 xfree(reply);
 403         } else {
 404                 debug2("buggy server: service_accept w/o service");
 405         }
 406         packet_check_eom();
 407         debug("SSH2_MSG_SERVICE_ACCEPT received");
 408
 409         if (options.preferred_authentications == NULL)
 410                 options.preferred_authentications = authmethods_get();
 411
 412         /* setup authentication context */
 413         memset(&authctxt, 0, sizeof(authctxt));
 414         pubkey_prepare(&authctxt);
 415         authctxt.server_user = server_user;
 416         authctxt.local_user = local_user;
 417         authctxt.host = host;
 418         authctxt.service = "ssh-connection";            /* service name */
 419         authctxt.success = 0;
 420         authctxt.method = authmethod_lookup("none");
 421         authctxt.authlist = NULL;
 422         authctxt.methoddata = NULL;
 423         authctxt.sensitive = sensitive;
 424         authctxt.info_req_seen = 0;
 425         if (authctxt.method == NULL)
 426                 fatal("ssh_userauth2: internal error: cannot send userauth none request");
 427
 428         /* initial userauth request */
 429         userauth_none(&authctxt);
 430
 431         dispatch_init(&input_userauth_error);
 432         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
 433         dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
 434         dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
 435         dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt);     /* loop until success */
 436
 437         pubkey_cleanup(&authctxt);
 438         dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
 439
 440         /* if the user wants to use the none cipher do it */
 441         /* post authentication and only if the right conditions are met */
 442         /* both of the NONE commands must be true and there must be no */
 443         /* tty allocated */
 444         if ((options.none_switch == 1) && (options.none_enabled == 1))
 445         {
 446                 if (!tty_flag) /* no null on tty sessions */
 447                 {
 448                         debug("Requesting none rekeying...");
 449                         myproposal[PROPOSAL_ENC_ALGS_STOC] = "none";
 450                         myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none";
 451                         kex_prop2buf(&xxx_kex->my,myproposal);
 452                         packet_request_rekeying();
 453                         fprintf(stderr, "WARNING: ENABLED NONE CIPHER\n");
 454                 }
 455                 else
 456                 {
 457                         /* requested NONE cipher when in a tty */
 458                         debug("Cannot switch to NONE cipher with tty allocated");
 459                         fprintf(stderr, "NONE cipher switch disabled when a TTY is allocated\n");
 460                 }
 461         }
 462         debug("Authentication succeeded (%s).", authctxt.method->name);
 463 }
 464
 465 void
 466 userauth(Authctxt *authctxt, char *authlist)
 467 {
 468         if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
 469                 authctxt->method->cleanup(authctxt);
 470
 471         if (authctxt->methoddata) {
 472                 xfree(authctxt->methoddata);
 473                 authctxt->methoddata = NULL;
 474         }
 475         if (authlist == NULL) {
 476                 authlist = authctxt->authlist;
 477         } else {
 478                 if (authctxt->authlist)
 479                         xfree(authctxt->authlist);
 480                 authctxt->authlist = authlist;
 481         }
 482         for (;;) {
 483                 Authmethod *method = authmethod_get(authlist);
 484                 if (method == NULL)
 485                         fatal("Permission denied (%s).", authlist);
 486                 authctxt->method = method;
 487
 488                 /* reset the per method handler */
 489                 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
 490                     SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
 491
 492                 /* and try new method */
 493                 if (method->userauth(authctxt) != 0) {
 494                         debug2("we sent a %s packet, wait for reply", method->name);
 495                         break;
 496                 } else {
 497                         debug2("we did not send a packet, disable method");
 498                         method->enabled = NULL;
 499                 }
 500         }
 501 }
 502
 503 /* ARGSUSED */
 504 void
 505 input_userauth_error(int type, u_int32_t seq, void *ctxt)
 506 {
 507         fatal("input_userauth_error: bad message during authentication: "
 508             "type %d", type);
 509 }
 510
 511 /* ARGSUSED */
 512 void
 513 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
 514 {
 515         char *msg, *raw, *lang;
 516         u_int len;
 517
 518         debug3("input_userauth_banner");
 519         raw = packet_get_string(&len);
 520         lang = packet_get_string(NULL);
 521         if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) {
 522                 if (len > 65536)
 523                         len = 65536;
 524                 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */
 525                 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL);
 526                 fprintf(stderr, "%s", msg);
 527                 xfree(msg);
 528         }
 529         xfree(raw);
 530         xfree(lang);
 531 }
 532
 533 /* ARGSUSED */
 534 void
 535 input_userauth_success(int type, u_int32_t seq, void *ctxt)
 536 {
 537         Authctxt *authctxt = ctxt;
 538         if (authctxt == NULL)
 539                 fatal("input_userauth_success: no authentication context");
 540         if (authctxt->authlist) {
 541                 xfree(authctxt->authlist);
 542                 authctxt->authlist = NULL;
 543         }
 544         if (authctxt->methoddata) {
 545                 xfree(authctxt->methoddata);
 546                 authctxt->methoddata = NULL;
 547         }
 548         authctxt->success = 1;                  /* break out */
 549 }
 550
 551 /* ARGSUSED */
 552 void
 553 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
 554 {
 555         Authctxt *authctxt = ctxt;
 556         char *authlist = NULL;
 557         int partial;
 558
 559         if (authctxt == NULL)
 560                 fatal("input_userauth_failure: no authentication context");
 561
 562         authlist = packet_get_string(NULL);
 563         partial = packet_get_char();
 564         packet_check_eom();
 565
 566         if (partial != 0)
 567                 logit("Authenticated with partial success.");
 568         debug("Authentications that can continue: %s", authlist);
 569
 570         userauth(authctxt, authlist);
 571 }
 572
 573 /* ARGSUSED */
 574 void
 575 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
 576 {
 577         Authctxt *authctxt = ctxt;
 578         Key *key = NULL;
 579         Identity *id = NULL;
 580         Buffer b;
 581         int pktype, sent = 0;
 582         u_int alen, blen;
 583         char *pkalg, *fp;
 584         u_char *pkblob;
 585
 586         if (authctxt == NULL)
 587                 fatal("input_userauth_pk_ok: no authentication context");
 588         if (datafellows & SSH_BUG_PKOK) {
 589                 /* this is similar to SSH_BUG_PKAUTH */
 590                 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
 591                 pkblob = packet_get_string(&blen);
 592                 buffer_init(&b);
 593                 buffer_append(&b, pkblob, blen);
 594                 pkalg = buffer_get_string(&b, &alen);
 595                 buffer_free(&b);
 596         } else {
 597                 pkalg = packet_get_string(&alen);
 598                 pkblob = packet_get_string(&blen);
 599         }
 600         packet_check_eom();
 601
 602         debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
 603
 604         if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
 605                 debug("unknown pkalg %s", pkalg);
 606                 goto done;
 607         }
 608         if ((key = key_from_blob(pkblob, blen)) == NULL) {
 609                 debug("no key from blob. pkalg %s", pkalg);
 610                 goto done;
 611         }
 612         if (key->type != pktype) {
 613                 error("input_userauth_pk_ok: type mismatch "
 614                     "for decoded key (received %d, expected %d)",
 615                     key->type, pktype);
 616                 goto done;
 617         }
 618         fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
 619         debug2("input_userauth_pk_ok: fp %s", fp);
 620         xfree(fp);
 621
 622         /*
 623          * search keys in the reverse order, because last candidate has been
 624          * moved to the end of the queue.  this also avoids confusion by
 625          * duplicate keys
 626          */
 627         TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
 628                 if (key_equal(key, id->key)) {
 629                         sent = sign_and_send_pubkey(authctxt, id);
 630                         break;
 631                 }
 632         }
 633 done:
 634         if (key != NULL)
 635                 key_free(key);
 636         xfree(pkalg);
 637         xfree(pkblob);
 638
 639         /* try another method if we did not send a packet */
 640         if (sent == 0)
 641                 userauth(authctxt, NULL);
 642 }
 643
 644 #ifdef GSSAPI
 645 int
 646 userauth_gssapi(Authctxt *authctxt)
 647 {
 648         Gssctxt *gssctxt = NULL;
 649         static gss_OID_set gss_supported = NULL;
 650         static u_int mech = 0;
 651         OM_uint32 min;
 652         int ok = 0;
 653         char *gss_host = NULL;
 654
 655         if (!options.gss_authentication) {
 656                 verbose("GSSAPI authentication disabled.");
 657                 return 0;
 658         }
 659
 660         if (options.gss_trust_dns)
 661                 gss_host = (char *)get_canonical_hostname(1);
 662         else
 663                 gss_host = (char *)authctxt->host;
 664
 665         /* Try one GSSAPI method at a time, rather than sending them all at
 666          * once. */
 667
 668         if (gss_supported == NULL)
 669                 if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) {
 670                         gss_supported = NULL;
 671                         return 0;
 672                 }
 673
 674         /* Check to see if the mechanism is usable before we offer it */
 675         while (mech < gss_supported->count && !ok) {
 676                 /* My DER encoding requires length<128 */
 677                 if (gss_supported->elements[mech].length < 128 &&
 678                     ssh_gssapi_check_mechanism(&gssctxt,
 679                     &gss_supported->elements[mech], gss_host,
 680                     options.gss_client_identity)) {
 681                         ok = 1; /* Mechanism works */
 682                 } else {
 683                         mech++;
 684                 }
 685         }
 686
 687         if (!ok)
 688                 return 0;
 689
 690         authctxt->methoddata=(void *)gssctxt;
 691
 692         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 693         packet_put_cstring(authctxt->server_user);
 694         packet_put_cstring(authctxt->service);
 695         packet_put_cstring(authctxt->method->name);
 696
 697         packet_put_int(1);
 698
 699         packet_put_int((gss_supported->elements[mech].length) + 2);
 700         packet_put_char(SSH_GSS_OIDTYPE);
 701         packet_put_char(gss_supported->elements[mech].length);
 702         packet_put_raw(gss_supported->elements[mech].elements,
 703             gss_supported->elements[mech].length);
 704
 705         packet_send();
 706
 707         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
 708         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
 709         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
 710         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
 711
 712         mech++; /* Move along to next candidate */
 713
 714         return 1;
 715 }
 716
 717 static OM_uint32
 718 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
 719 {
 720         Authctxt *authctxt = ctxt;
 721         Gssctxt *gssctxt = authctxt->methoddata;
 722         gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
 723         gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
 724         gss_buffer_desc gssbuf;
 725         OM_uint32 status, ms, flags;
 726         Buffer b;
 727
 728         status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
 729             recv_tok, &send_tok, &flags);
 730
 731         if (send_tok.length > 0) {
 732                 if (GSS_ERROR(status))
 733                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
 734                 else
 735                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
 736
 737                 packet_put_string(send_tok.value, send_tok.length);
 738                 packet_send();
 739                 gss_release_buffer(&ms, &send_tok);
 740         }
 741
 742         if (status == GSS_S_COMPLETE) {
 743                 /* send either complete or MIC, depending on mechanism */
 744                 if (strcmp(authctxt->method->name,"gssapi")==0 ||
 745                     (!(flags & GSS_C_INTEG_FLAG))) {
 746                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
 747                         packet_send();
 748                 } else {
 749                         ssh_gssapi_buildmic(&b, authctxt->server_user,
 750                             authctxt->service, "gssapi-with-mic");
 751
 752                         gssbuf.value = buffer_ptr(&b);
 753                         gssbuf.length = buffer_len(&b);
 754
 755                         status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
 756
 757                         if (!GSS_ERROR(status)) {
 758                                 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
 759                                 packet_put_string(mic.value, mic.length);
 760
 761                                 packet_send();
 762                         }
 763
 764                         buffer_free(&b);
 765                         gss_release_buffer(&ms, &mic);
 766                 }
 767         }
 768
 769         return status;
 770 }
 771
 772 /* ARGSUSED */
 773 void
 774 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
 775 {
 776         Authctxt *authctxt = ctxt;
 777         Gssctxt *gssctxt;
 778         u_int oidlen;
 779         u_char *oidv;
 780
 781         if (authctxt == NULL)
 782                 fatal("input_gssapi_response: no authentication context");
 783         gssctxt = authctxt->methoddata;
 784
 785         /* Setup our OID */
 786         oidv = packet_get_string(&oidlen);
 787
 788         if (oidlen <= 2 ||
 789             oidv[0] != SSH_GSS_OIDTYPE ||
 790             oidv[1] != oidlen - 2) {
 791                 xfree(oidv);
 792                 debug("Badly encoded mechanism OID received");
 793                 userauth(authctxt, NULL);
 794                 return;
 795         }
 796
 797         if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
 798                 fatal("Server returned different OID than expected");
 799
 800         packet_check_eom();
 801
 802         xfree(oidv);
 803
 804         if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
 805                 /* Start again with next method on list */
 806                 debug("Trying to start again");
 807                 userauth(authctxt, NULL);
 808                 return;
 809         }
 810 }
 811
 812 /* ARGSUSED */
 813 void
 814 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
 815 {
 816         Authctxt *authctxt = ctxt;
 817         gss_buffer_desc recv_tok;
 818         OM_uint32 status;
 819         u_int slen;
 820
 821         if (authctxt == NULL)
 822                 fatal("input_gssapi_response: no authentication context");
 823
 824         recv_tok.value = packet_get_string(&slen);
 825         recv_tok.length = slen; /* safe typecast */
 826
 827         packet_check_eom();
 828
 829         status = process_gssapi_token(ctxt, &recv_tok);
 830
 831         xfree(recv_tok.value);
 832
 833         if (GSS_ERROR(status)) {
 834                 /* Start again with the next method in the list */
 835                 userauth(authctxt, NULL);
 836                 return;
 837         }
 838 }
 839
 840 /* ARGSUSED */
 841 void
 842 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
 843 {
 844         Authctxt *authctxt = ctxt;
 845         Gssctxt *gssctxt;
 846         gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
 847         gss_buffer_desc recv_tok;
 848         OM_uint32 status, ms;
 849         u_int len;
 850
 851         if (authctxt == NULL)
 852                 fatal("input_gssapi_response: no authentication context");
 853         gssctxt = authctxt->methoddata;
 854
 855         recv_tok.value = packet_get_string(&len);
 856         recv_tok.length = len;
 857
 858         packet_check_eom();
 859
 860         /* Stick it into GSSAPI and see what it says */
 861         status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
 862             &recv_tok, &send_tok, NULL);
 863
 864         xfree(recv_tok.value);
 865         gss_release_buffer(&ms, &send_tok);
 866
 867         /* Server will be returning a failed packet after this one */
 868 }
 869
 870 /* ARGSUSED */
 871 void
 872 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
 873 {
 874         OM_uint32 maj, min;
 875         char *msg;
 876         char *lang;
 877
 878         maj=packet_get_int();
 879         min=packet_get_int();
 880         msg=packet_get_string(NULL);
 881         lang=packet_get_string(NULL);
 882
 883         packet_check_eom();
 884
 885         debug("Server GSSAPI Error:\n%s", msg);
 886         xfree(msg);
 887         xfree(lang);
 888 }
 889
 890 #ifdef GSI
 891 extern
 892 const gss_OID_desc * const              gss_mech_globus_gssapi_openssl;
 893 #define is_gsi_oid(oid) \
 894   (oid->length == gss_mech_globus_gssapi_openssl->length && \
 895    (memcmp(oid->elements, gss_mech_globus_gssapi_openssl->elements, \
 896            oid->length) == 0))
 897 #endif
 898
 899 int
 900 userauth_external(Authctxt *authctxt)
 901 {
 902     static int attempt = 0;
 903
 904     if (attempt++ >= 1)
 905         return 0;
 906
 907         /* The client MUST NOT try this method if initial key exchange
 908            was not performed using a GSSAPI-based key exchange
 909            method. */
 910         if (gss_kex_context == NULL) {
 911                 debug2("gsskex not performed, skipping external-keyx");
 912                 return 0;
 913         }
 914
 915     debug2("userauth_external");
 916     packet_start(SSH2_MSG_USERAUTH_REQUEST);
 917 #ifdef GSI
 918     if (options.implicit && is_gsi_oid(gss_kex_context->oid)) {
 919         packet_put_cstring("");
 920         } else {
 921 #endif
 922     packet_put_cstring(authctxt->server_user);
 923 #ifdef GSI
 924         }
 925 #endif
 926     packet_put_cstring(authctxt->service);
 927     packet_put_cstring(authctxt->method->name);
 928     packet_send();
 929     packet_write_wait();
 930     return 1;
 931 }
 932 int
 933 userauth_gsskeyex(Authctxt *authctxt)
 934 {
 935         Buffer b;
 936         gss_buffer_desc gssbuf;
 937         gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
 938         OM_uint32 ms;
 939
 940         static int attempt = 0;
 941         if (attempt++ >= 1)
 942                 return (0);
 943
 944         if (gss_kex_context == NULL) {
 945                 debug("No valid Key exchange context");
 946                 return (0);
 947         }
 948
 949 #ifdef GSI
 950     if (options.implicit && is_gsi_oid(gss_kex_context->oid)) {
 951         ssh_gssapi_buildmic(&b, "", authctxt->service, "gssapi-keyex");
 952         } else {
 953 #endif
 954         ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service,
 955                             "gssapi-keyex");
 956 #ifdef GSI
 957         }
 958 #endif
 959
 960         gssbuf.value = buffer_ptr(&b);
 961         gssbuf.length = buffer_len(&b);
 962
 963         if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) {
 964                 buffer_free(&b);
 965                 return (0);
 966         }
 967
 968         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 969 #ifdef GSI
 970     if (options.implicit && is_gsi_oid(gss_kex_context->oid)) {
 971         packet_put_cstring("");
 972         } else {
 973 #endif
 974         packet_put_cstring(authctxt->server_user);
 975 #ifdef GSI
 976         }
 977 #endif
 978         packet_put_cstring(authctxt->service);
 979         packet_put_cstring(authctxt->method->name);
 980         packet_put_string(mic.value, mic.length);
 981         packet_send();
 982
 983         buffer_free(&b);
 984         gss_release_buffer(&ms, &mic);
 985
 986         return (1);
 987 }
 988
 989 #endif /* GSSAPI */
 990
 991 int
 992 userauth_none(Authctxt *authctxt)
 993 {
 994         /* initial userauth request */
 995         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 996         packet_put_cstring(authctxt->server_user);
 997         packet_put_cstring(authctxt->service);
 998         packet_put_cstring(authctxt->method->name);
 999         packet_send();
1000         return 1;
1001 }
1002
1003 int
1004 userauth_passwd(Authctxt *authctxt)
1005 {
1006         static int attempt = 0;
1007         char prompt[150];
1008         char *password;
1009
1010         if (attempt++ >= options.number_of_password_prompts)
1011                 return 0;
1012
1013         if (attempt != 1)
1014                 error("Permission denied, please try again.");
1015
1016         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1017             authctxt->server_user, authctxt->host);
1018         password = read_passphrase(prompt, 0);
1019         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1020         packet_put_cstring(authctxt->server_user);
1021         packet_put_cstring(authctxt->service);
1022         packet_put_cstring(authctxt->method->name);
1023         packet_put_char(0);
1024         packet_put_cstring(password);
1025         memset(password, 0, strlen(password));
1026         xfree(password);
1027         packet_add_padding(64);
1028         packet_send();
1029
1030         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
1031             &input_userauth_passwd_changereq);
1032
1033         return 1;
1034 }
1035
1036 /*
1037  * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
1038  */
1039 /* ARGSUSED */
1040 void
1041 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
1042 {
1043         Authctxt *authctxt = ctxt;
1044         char *info, *lang, *password = NULL, *retype = NULL;
1045         char prompt[150];
1046
1047         debug2("input_userauth_passwd_changereq");
1048
1049         if (authctxt == NULL)
1050                 fatal("input_userauth_passwd_changereq: "
1051                     "no authentication context");
1052
1053         info = packet_get_string(NULL);
1054         lang = packet_get_string(NULL);
1055         if (strlen(info) > 0)
1056                 logit("%s", info);
1057         xfree(info);
1058         xfree(lang);
1059         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1060         packet_put_cstring(authctxt->server_user);
1061         packet_put_cstring(authctxt->service);
1062         packet_put_cstring(authctxt->method->name);
1063         packet_put_char(1);                     /* additional info */
1064         snprintf(prompt, sizeof(prompt),
1065             "Enter %.30s@%.128s's old password: ",
1066             authctxt->server_user, authctxt->host);
1067         password = read_passphrase(prompt, 0);
1068         packet_put_cstring(password);
1069         memset(password, 0, strlen(password));
1070         xfree(password);
1071         password = NULL;
1072         while (password == NULL) {
1073                 snprintf(prompt, sizeof(prompt),
1074                     "Enter %.30s@%.128s's new password: ",
1075                     authctxt->server_user, authctxt->host);
1076                 password = read_passphrase(prompt, RP_ALLOW_EOF);
1077                 if (password == NULL) {
1078                         /* bail out */
1079                         return;
1080                 }
1081                 snprintf(prompt, sizeof(prompt),
1082                     "Retype %.30s@%.128s's new password: ",
1083                     authctxt->server_user, authctxt->host);
1084                 retype = read_passphrase(prompt, 0);
1085                 if (strcmp(password, retype) != 0) {
1086                         memset(password, 0, strlen(password));
1087                         xfree(password);
1088                         logit("Mismatch; try again, EOF to quit.");
1089                         password = NULL;
1090                 }
1091                 memset(retype, 0, strlen(retype));
1092                 xfree(retype);
1093         }
1094         packet_put_cstring(password);
1095         memset(password, 0, strlen(password));
1096         xfree(password);
1097         packet_add_padding(64);
1098         packet_send();
1099
1100         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
1101             &input_userauth_passwd_changereq);
1102 }
1103
1104 #ifdef JPAKE
1105 static char *
1106 pw_encrypt(const char *password, const char *crypt_scheme, const char *salt)
1107 {
1108         /* OpenBSD crypt(3) handles all of these */
1109         if (strcmp(crypt_scheme, "crypt") == 0 ||
1110             strcmp(crypt_scheme, "bcrypt") == 0 ||
1111             strcmp(crypt_scheme, "md5crypt") == 0 ||
1112             strcmp(crypt_scheme, "crypt-extended") == 0)
1113                 return xstrdup(crypt(password, salt));
1114         error("%s: unsupported password encryption scheme \"%.100s\"",
1115             __func__, crypt_scheme);
1116         return NULL;
1117 }
1118
1119 static BIGNUM *
1120 jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme,
1121     const char *salt)
1122 {
1123         char prompt[256], *password, *crypted;
1124         u_char *secret;
1125         u_int secret_len;
1126         BIGNUM *ret;
1127
1128         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ",
1129             authctxt->server_user, authctxt->host);
1130         password = read_passphrase(prompt, 0);
1131
1132         if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) {
1133                 logit("Disabling %s authentication", authctxt->method->name);
1134                 authctxt->method->enabled = NULL;
1135                 /* Continue with an empty password to fail gracefully */
1136                 crypted = xstrdup("");
1137         }
1138
1139 #ifdef JPAKE_DEBUG
1140         debug3("%s: salt = %s", __func__, salt);
1141         debug3("%s: scheme = %s", __func__, crypt_scheme);
1142         debug3("%s: crypted = %s", __func__, crypted);
1143 #endif
1144
1145         if (hash_buffer(crypted, strlen(crypted), EVP_sha256(),
1146             &secret, &secret_len) != 0)
1147                 fatal("%s: hash_buffer", __func__);
1148
1149         bzero(password, strlen(password));
1150         bzero(crypted, strlen(crypted));
1151         xfree(password);
1152         xfree(crypted);
1153
1154         if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL)
1155                 fatal("%s: BN_bin2bn (secret)", __func__);
1156         bzero(secret, secret_len);
1157         xfree(secret);
1158
1159         return ret;
1160 }
1161
1162 /* ARGSUSED */
1163 void
1164 input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt)
1165 {
1166         Authctxt *authctxt = ctxt;
1167         struct jpake_ctx *pctx = authctxt->methoddata;
1168         u_char *x3_proof, *x4_proof, *x2_s_proof;
1169         u_int x3_proof_len, x4_proof_len, x2_s_proof_len;
1170         char *crypt_scheme, *salt;
1171
1172         /* Disable this message */
1173         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL);
1174
1175         if ((pctx->g_x3 = BN_new()) == NULL ||
1176             (pctx->g_x4 = BN_new()) == NULL)
1177                 fatal("%s: BN_new", __func__);
1178
1179         /* Fetch step 1 values */
1180         crypt_scheme = packet_get_string(NULL);
1181         salt = packet_get_string(NULL);
1182         pctx->server_id = packet_get_string(&pctx->server_id_len);
1183         packet_get_bignum2(pctx->g_x3);
1184         packet_get_bignum2(pctx->g_x4);
1185         x3_proof = packet_get_string(&x3_proof_len);
1186         x4_proof = packet_get_string(&x4_proof_len);
1187         packet_check_eom();
1188
1189         JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__));
1190
1191         /* Obtain password and derive secret */
1192         pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt);
1193         bzero(crypt_scheme, strlen(crypt_scheme));
1194         bzero(salt, strlen(salt));
1195         xfree(crypt_scheme);
1196         xfree(salt);
1197         JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__));
1198
1199         /* Calculate step 2 values */
1200         jpake_step2(pctx->grp, pctx->s, pctx->g_x1,
1201             pctx->g_x3, pctx->g_x4, pctx->x2,
1202             pctx->server_id, pctx->server_id_len,
1203             pctx->client_id, pctx->client_id_len,
1204             x3_proof, x3_proof_len,
1205             x4_proof, x4_proof_len,
1206             &pctx->a,
1207             &x2_s_proof, &x2_s_proof_len);
1208
1209         bzero(x3_proof, x3_proof_len);
1210         bzero(x4_proof, x4_proof_len);
1211         xfree(x3_proof);
1212         xfree(x4_proof);
1213
1214         JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__));
1215
1216         /* Send values for step 2 */
1217         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2);
1218         packet_put_bignum2(pctx->a);
1219         packet_put_string(x2_s_proof, x2_s_proof_len);
1220         packet_send();
1221
1222         bzero(x2_s_proof, x2_s_proof_len);
1223         xfree(x2_s_proof);
1224
1225         /* Expect step 2 packet from peer */
1226         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2,
1227             input_userauth_jpake_server_step2);
1228 }
1229
1230 /* ARGSUSED */
1231 void
1232 input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt)
1233 {
1234         Authctxt *authctxt = ctxt;
1235         struct jpake_ctx *pctx = authctxt->methoddata;
1236         u_char *x4_s_proof;
1237         u_int x4_s_proof_len;
1238
1239         /* Disable this message */
1240         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL);
1241
1242         if ((pctx->b = BN_new()) == NULL)
1243                 fatal("%s: BN_new", __func__);
1244
1245         /* Fetch step 2 values */
1246         packet_get_bignum2(pctx->b);
1247         x4_s_proof = packet_get_string(&x4_s_proof_len);
1248         packet_check_eom();
1249
1250         JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__));
1251
1252         /* Derive shared key and calculate confirmation hash */
1253         jpake_key_confirm(pctx->grp, pctx->s, pctx->b,
1254             pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4,
1255             pctx->client_id, pctx->client_id_len,
1256             pctx->server_id, pctx->server_id_len,
1257             session_id2, session_id2_len,
1258             x4_s_proof, x4_s_proof_len,
1259             &pctx->k,
1260             &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len);
1261
1262         bzero(x4_s_proof, x4_s_proof_len);
1263         xfree(x4_s_proof);
1264
1265         JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__));
1266
1267         /* Send key confirmation proof */
1268         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM);
1269         packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len);
1270         packet_send();
1271
1272         /* Expect confirmation from peer */
1273         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM,
1274             input_userauth_jpake_server_confirm);
1275 }
1276
1277 /* ARGSUSED */
1278 void
1279 input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt)
1280 {
1281         Authctxt *authctxt = ctxt;
1282         struct jpake_ctx *pctx = authctxt->methoddata;
1283
1284         /* Disable this message */
1285         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL);
1286
1287         pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len);
1288         packet_check_eom();
1289
1290         JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__));
1291
1292         /* Verify expected confirmation hash */
1293         if (jpake_check_confirm(pctx->k,
1294             pctx->server_id, pctx->server_id_len,
1295             session_id2, session_id2_len,
1296             pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1)
1297                 debug("%s: %s success", __func__, authctxt->method->name);
1298         else {
1299                 debug("%s: confirmation mismatch", __func__);
1300                 /* XXX stash this so if auth succeeds then we can warn/kill */
1301         }
1302
1303         userauth_jpake_cleanup(authctxt);
1304 }
1305 #endif /* JPAKE */
1306
1307 static int
1308 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
1309     u_char *data, u_int datalen)
1310 {
1311         Key *prv;
1312         int ret;
1313
1314         /* the agent supports this key */
1315         if (id->ac)
1316                 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
1317                     data, datalen));
1318         /*
1319          * we have already loaded the private key or
1320          * the private key is stored in external hardware
1321          */
1322         if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
1323                 return (key_sign(id->key, sigp, lenp, data, datalen));
1324         /* load the private key from the file */
1325         if ((prv = load_identity_file(id->filename)) == NULL)
1326                 return (-1);
1327         ret = key_sign(prv, sigp, lenp, data, datalen);
1328         key_free(prv);
1329         return (ret);
1330 }
1331
1332 static int
1333 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
1334 {
1335         Buffer b;
1336         u_char *blob, *signature;
1337         u_int bloblen, slen;
1338         u_int skip = 0;
1339         int ret = -1;
1340         int have_sig = 1;
1341
1342         debug3("sign_and_send_pubkey");
1343
1344         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1345                 /* we cannot handle this key */
1346                 debug3("sign_and_send_pubkey: cannot handle key");
1347                 return 0;
1348         }
1349         /* data to be signed */
1350         buffer_init(&b);
1351         if (datafellows & SSH_OLD_SESSIONID) {
1352                 buffer_append(&b, session_id2, session_id2_len);
1353                 skip = session_id2_len;
1354         } else {
1355                 buffer_put_string(&b, session_id2, session_id2_len);
1356                 skip = buffer_len(&b);
1357         }
1358         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1359         buffer_put_cstring(&b, authctxt->server_user);
1360         buffer_put_cstring(&b,
1361             datafellows & SSH_BUG_PKSERVICE ?
1362             "ssh-userauth" :
1363             authctxt->service);
1364         if (datafellows & SSH_BUG_PKAUTH) {
1365                 buffer_put_char(&b, have_sig);
1366         } else {
1367                 buffer_put_cstring(&b, authctxt->method->name);
1368                 buffer_put_char(&b, have_sig);
1369                 buffer_put_cstring(&b, key_ssh_name(id->key));
1370         }
1371         buffer_put_string(&b, blob, bloblen);
1372
1373         /* generate signature */
1374         ret = identity_sign(id, &signature, &slen,
1375             buffer_ptr(&b), buffer_len(&b));
1376         if (ret == -1) {
1377                 xfree(blob);
1378                 buffer_free(&b);
1379                 return 0;
1380         }
1381 #ifdef DEBUG_PK
1382         buffer_dump(&b);
1383 #endif
1384         if (datafellows & SSH_BUG_PKSERVICE) {
1385                 buffer_clear(&b);
1386                 buffer_append(&b, session_id2, session_id2_len);
1387                 skip = session_id2_len;
1388                 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1389                 buffer_put_cstring(&b, authctxt->server_user);
1390                 buffer_put_cstring(&b, authctxt->service);
1391                 buffer_put_cstring(&b, authctxt->method->name);
1392                 buffer_put_char(&b, have_sig);
1393                 if (!(datafellows & SSH_BUG_PKAUTH))
1394                         buffer_put_cstring(&b, key_ssh_name(id->key));
1395                 buffer_put_string(&b, blob, bloblen);
1396         }
1397         xfree(blob);
1398
1399         /* append signature */
1400         buffer_put_string(&b, signature, slen);
1401         xfree(signature);
1402
1403         /* skip session id and packet type */
1404         if (buffer_len(&b) < skip + 1)
1405                 fatal("userauth_pubkey: internal error");
1406         buffer_consume(&b, skip + 1);
1407
1408         /* put remaining data from buffer into packet */
1409         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1410         packet_put_raw(buffer_ptr(&b), buffer_len(&b));
1411         buffer_free(&b);
1412         packet_send();
1413
1414         return 1;
1415 }
1416
1417 static int
1418 send_pubkey_test(Authctxt *authctxt, Identity *id)
1419 {
1420         u_char *blob;
1421         u_int bloblen, have_sig = 0;
1422
1423         debug3("send_pubkey_test");
1424
1425         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1426                 /* we cannot handle this key */
1427                 debug3("send_pubkey_test: cannot handle key");
1428                 return 0;
1429         }
1430         /* register callback for USERAUTH_PK_OK message */
1431         dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
1432
1433         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1434         packet_put_cstring(authctxt->server_user);
1435         packet_put_cstring(authctxt->service);
1436         packet_put_cstring(authctxt->method->name);
1437         packet_put_char(have_sig);
1438         if (!(datafellows & SSH_BUG_PKAUTH))
1439                 packet_put_cstring(key_ssh_name(id->key));
1440         packet_put_string(blob, bloblen);
1441         xfree(blob);
1442         packet_send();
1443         return 1;
1444 }
1445
1446 static Key *
1447 load_identity_file(char *filename)
1448 {
1449         Key *private;
1450         char prompt[300], *passphrase;
1451         int perm_ok, quit, i;
1452         struct stat st;
1453
1454         if (stat(filename, &st) < 0) {
1455                 debug3("no such identity: %s", filename);
1456                 return NULL;
1457         }
1458         private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
1459         if (!perm_ok)
1460                 return NULL;
1461         if (private == NULL) {
1462                 if (options.batch_mode)
1463                         return NULL;
1464                 snprintf(prompt, sizeof prompt,
1465                     "Enter passphrase for key '%.100s': ", filename);
1466                 for (i = 0; i < options.number_of_password_prompts; i++) {
1467                         passphrase = read_passphrase(prompt, 0);
1468                         if (strcmp(passphrase, "") != 0) {
1469                                 private = key_load_private_type(KEY_UNSPEC,
1470                                     filename, passphrase, NULL, NULL);
1471                                 quit = 0;
1472                         } else {
1473                                 debug2("no passphrase given, try next key");
1474                                 quit = 1;
1475                         }
1476                         memset(passphrase, 0, strlen(passphrase));
1477                         xfree(passphrase);
1478                         if (private != NULL || quit)
1479                                 break;
1480                         debug2("bad passphrase given, try again...");
1481                 }
1482         }
1483         return private;
1484 }
1485
1486 /*
1487  * try keys in the following order:
1488  *      1. agent keys that are found in the config file
1489  *      2. other agent keys
1490  *      3. keys that are only listed in the config file
1491  */
1492 static void
1493 pubkey_prepare(Authctxt *authctxt)
1494 {
1495         Identity *id;
1496         Idlist agent, files, *preferred;
1497         Key *key;
1498         AuthenticationConnection *ac;
1499         char *comment;
1500         int i, found;
1501
1502         TAILQ_INIT(&agent);     /* keys from the agent */
1503         TAILQ_INIT(&files);     /* keys from the config file */
1504         preferred = &authctxt->keys;
1505         TAILQ_INIT(preferred);  /* preferred order of keys */
1506
1507         /* list of keys stored in the filesystem */
1508         for (i = 0; i < options.num_identity_files; i++) {
1509                 key = options.identity_keys[i];
1510                 if (key && key->type == KEY_RSA1)
1511                         continue;
1512                 options.identity_keys[i] = NULL;
1513                 id = xcalloc(1, sizeof(*id));
1514                 id->key = key;
1515                 id->filename = xstrdup(options.identity_files[i]);
1516                 TAILQ_INSERT_TAIL(&files, id, next);
1517         }
1518         /* list of keys supported by the agent */
1519         if ((ac = ssh_get_authentication_connection())) {
1520                 for (key = ssh_get_first_identity(ac, &comment, 2);
1521                     key != NULL;
1522                     key = ssh_get_next_identity(ac, &comment, 2)) {
1523                         found = 0;
1524                         TAILQ_FOREACH(id, &files, next) {
1525                                 /* agent keys from the config file are preferred */
1526                                 if (key_equal(key, id->key)) {
1527                                         key_free(key);
1528                                         xfree(comment);
1529                                         TAILQ_REMOVE(&files, id, next);
1530                                         TAILQ_INSERT_TAIL(preferred, id, next);
1531                                         id->ac = ac;
1532                                         found = 1;
1533                                         break;
1534                                 }
1535                         }
1536                         if (!found && !options.identities_only) {
1537                                 id = xcalloc(1, sizeof(*id));
1538                                 id->key = key;
1539                                 id->filename = comment;
1540                                 id->ac = ac;
1541                                 TAILQ_INSERT_TAIL(&agent, id, next);
1542                         }
1543                 }
1544                 /* append remaining agent keys */
1545                 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1546                         TAILQ_REMOVE(&agent, id, next);
1547                         TAILQ_INSERT_TAIL(preferred, id, next);
1548                 }
1549                 authctxt->agent = ac;
1550         }
1551         /* append remaining keys from the config file */
1552         for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1553                 TAILQ_REMOVE(&files, id, next);
1554                 TAILQ_INSERT_TAIL(preferred, id, next);
1555         }
1556         TAILQ_FOREACH(id, preferred, next) {
1557                 debug2("key: %s (%p)", id->filename, id->key);
1558         }
1559 }
1560
1561 static void
1562 pubkey_cleanup(Authctxt *authctxt)
1563 {
1564         Identity *id;
1565
1566         if (authctxt->agent != NULL)
1567                 ssh_close_authentication_connection(authctxt->agent);
1568         for (id = TAILQ_FIRST(&authctxt->keys); id;
1569             id = TAILQ_FIRST(&authctxt->keys)) {
1570                 TAILQ_REMOVE(&authctxt->keys, id, next);
1571                 if (id->key)
1572                         key_free(id->key);
1573                 if (id->filename)
1574                         xfree(id->filename);
1575                 xfree(id);
1576         }
1577 }
1578
1579 int
1580 userauth_pubkey(Authctxt *authctxt)
1581 {
1582         Identity *id;
1583         int sent = 0;
1584
1585         while ((id = TAILQ_FIRST(&authctxt->keys))) {
1586                 if (id->tried++)
1587                         return (0);
1588                 /* move key to the end of the queue */
1589                 TAILQ_REMOVE(&authctxt->keys, id, next);
1590                 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1591                 /*
1592                  * send a test message if we have the public key. for
1593                  * encrypted keys we cannot do this and have to load the
1594                  * private key instead
1595                  */
1596                 if (id->key && id->key->type != KEY_RSA1) {
1597                         debug("Offering public key: %s", id->filename);
1598                         sent = send_pubkey_test(authctxt, id);
1599                 } else if (id->key == NULL) {
1600                         debug("Trying private key: %s", id->filename);
1601                         id->key = load_identity_file(id->filename);
1602                         if (id->key != NULL) {
1603                                 id->isprivate = 1;
1604                                 sent = sign_and_send_pubkey(authctxt, id);
1605                                 key_free(id->key);
1606                                 id->key = NULL;
1607                         }
1608                 }
1609                 if (sent)
1610                         return (sent);
1611         }
1612         return (0);
1613 }
1614
1615 /*
1616  * Send userauth request message specifying keyboard-interactive method.
1617  */
1618 int
1619 userauth_kbdint(Authctxt *authctxt)
1620 {
1621         static int attempt = 0;
1622
1623         if (attempt++ >= options.number_of_password_prompts)
1624                 return 0;
1625         /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1626         if (attempt > 1 && !authctxt->info_req_seen) {
1627                 debug3("userauth_kbdint: disable: no info_req_seen");
1628                 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1629                 return 0;
1630         }
1631
1632         debug2("userauth_kbdint");
1633         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1634         packet_put_cstring(authctxt->server_user);
1635         packet_put_cstring(authctxt->service);
1636         packet_put_cstring(authctxt->method->name);
1637         packet_put_cstring("");                                 /* lang */
1638         packet_put_cstring(options.kbd_interactive_devices ?
1639             options.kbd_interactive_devices : "");
1640         packet_send();
1641
1642         dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1643         return 1;
1644 }
1645
1646 /*
1647  * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1648  */
1649 void
1650 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1651 {
1652         Authctxt *authctxt = ctxt;
1653         char *name, *inst, *lang, *prompt, *response;
1654         u_int num_prompts, i;
1655         int echo = 0;
1656
1657         debug2("input_userauth_info_req");
1658
1659         if (authctxt == NULL)
1660                 fatal("input_userauth_info_req: no authentication context");
1661
1662         authctxt->info_req_seen = 1;
1663
1664         name = packet_get_string(NULL);
1665         inst = packet_get_string(NULL);
1666         lang = packet_get_string(NULL);
1667         if (strlen(name) > 0)
1668                 logit("%s", name);
1669         if (strlen(inst) > 0)
1670                 logit("%s", inst);
1671         xfree(name);
1672         xfree(inst);
1673         xfree(lang);
1674
1675         num_prompts = packet_get_int();
1676         /*
1677          * Begin to build info response packet based on prompts requested.
1678          * We commit to providing the correct number of responses, so if
1679          * further on we run into a problem that prevents this, we have to
1680          * be sure and clean this up and send a correct error response.
1681          */
1682         packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1683         packet_put_int(num_prompts);
1684
1685         debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1686         for (i = 0; i < num_prompts; i++) {
1687                 prompt = packet_get_string(NULL);
1688                 echo = packet_get_char();
1689
1690                 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1691
1692                 packet_put_cstring(response);
1693                 memset(response, 0, strlen(response));
1694                 xfree(response);
1695                 xfree(prompt);
1696         }
1697         packet_check_eom(); /* done with parsing incoming message. */
1698
1699         packet_add_padding(64);
1700         packet_send();
1701 }
1702
1703 static int
1704 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1705     u_char *data, u_int datalen)
1706 {
1707         Buffer b;
1708         struct stat st;
1709         pid_t pid;
1710         int to[2], from[2], status, version = 2;
1711
1712         debug2("ssh_keysign called");
1713
1714         if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1715                 error("ssh_keysign: no installed: %s", strerror(errno));
1716                 return -1;
1717         }
1718         if (fflush(stdout) != 0)
1719                 error("ssh_keysign: fflush: %s", strerror(errno));
1720         if (pipe(to) < 0) {
1721                 error("ssh_keysign: pipe: %s", strerror(errno));
1722                 return -1;
1723         }
1724         if (pipe(from) < 0) {
1725                 error("ssh_keysign: pipe: %s", strerror(errno));
1726                 return -1;
1727         }
1728         if ((pid = fork()) < 0) {
1729                 error("ssh_keysign: fork: %s", strerror(errno));
1730                 return -1;
1731         }
1732         if (pid == 0) {
1733                 permanently_drop_suid(getuid());
1734                 close(from[0]);
1735                 if (dup2(from[1], STDOUT_FILENO) < 0)
1736                         fatal("ssh_keysign: dup2: %s", strerror(errno));
1737                 close(to[1]);
1738                 if (dup2(to[0], STDIN_FILENO) < 0)
1739                         fatal("ssh_keysign: dup2: %s", strerror(errno));
1740                 close(from[1]);
1741                 close(to[0]);
1742                 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1743                 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1744                     strerror(errno));
1745         }
1746         close(from[1]);
1747         close(to[0]);
1748
1749         buffer_init(&b);
1750         buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1751         buffer_put_string(&b, data, datalen);
1752         if (ssh_msg_send(to[1], version, &b) == -1)
1753                 fatal("ssh_keysign: couldn't send request");
1754
1755         if (ssh_msg_recv(from[0], &b) < 0) {
1756                 error("ssh_keysign: no reply");
1757                 buffer_free(&b);
1758                 return -1;
1759         }
1760         close(from[0]);
1761         close(to[1]);
1762
1763         while (waitpid(pid, &status, 0) < 0)
1764                 if (errno != EINTR)
1765                         break;
1766
1767         if (buffer_get_char(&b) != version) {
1768                 error("ssh_keysign: bad version");
1769                 buffer_free(&b);
1770                 return -1;
1771         }
1772         *sigp = buffer_get_string(&b, lenp);
1773         buffer_free(&b);
1774
1775         return 0;
1776 }
1777
1778 int
1779 userauth_hostbased(Authctxt *authctxt)
1780 {
1781         Key *private = NULL;
1782         Sensitive *sensitive = authctxt->sensitive;
1783         Buffer b;
1784         u_char *signature, *blob;
1785         char *chost, *pkalg, *p, myname[NI_MAXHOST];
1786         const char *service;
1787         u_int blen, slen;
1788         int ok, i, len, found = 0;
1789
1790         /* check for a useful key */
1791         for (i = 0; i < sensitive->nkeys; i++) {
1792                 private = sensitive->keys[i];
1793                 if (private && private->type != KEY_RSA1) {
1794                         found = 1;
1795                         /* we take and free the key */
1796                         sensitive->keys[i] = NULL;
1797                         break;
1798                 }
1799         }
1800         if (!found) {
1801                 debug("No more client hostkeys for hostbased authentication.");
1802                 return 0;
1803         }
1804         if (key_to_blob(private, &blob, &blen) == 0) {
1805                 key_free(private);
1806                 return 0;
1807         }
1808         /* figure out a name for the client host */
1809         p = NULL;
1810         if (packet_connection_is_on_socket())
1811                 p = get_local_name(packet_get_connection_in());
1812         if (p == NULL) {
1813                 if (gethostname(myname, sizeof(myname)) == -1) {
1814                         verbose("userauth_hostbased: gethostname: %s",
1815                             strerror(errno));
1816                 } else
1817                         p = xstrdup(myname);
1818         }
1819         if (p == NULL) {
1820                 error("userauth_hostbased: cannot get local ipaddr/name");
1821                 key_free(private);
1822                 xfree(blob);
1823                 return 0;
1824         }
1825         len = strlen(p) + 2;
1826         xasprintf(&chost, "%s.", p);
1827         debug2("userauth_hostbased: chost %s", chost);
1828         xfree(p);
1829
1830         service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1831             authctxt->service;
1832         pkalg = xstrdup(key_ssh_name(private));
1833         buffer_init(&b);
1834         /* construct data */
1835         buffer_put_string(&b, session_id2, session_id2_len);
1836         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1837         buffer_put_cstring(&b, authctxt->server_user);
1838         buffer_put_cstring(&b, service);
1839         buffer_put_cstring(&b, authctxt->method->name);
1840         buffer_put_cstring(&b, pkalg);
1841         buffer_put_string(&b, blob, blen);
1842         buffer_put_cstring(&b, chost);
1843         buffer_put_cstring(&b, authctxt->local_user);
1844 #ifdef DEBUG_PK
1845         buffer_dump(&b);
1846 #endif
1847         if (sensitive->external_keysign)
1848                 ok = ssh_keysign(private, &signature, &slen,
1849                     buffer_ptr(&b), buffer_len(&b));
1850         else
1851                 ok = key_sign(private, &signature, &slen,
1852                     buffer_ptr(&b), buffer_len(&b));
1853         key_free(private);
1854         buffer_free(&b);
1855         if (ok != 0) {
1856                 error("key_sign failed");
1857                 xfree(chost);
1858                 xfree(pkalg);
1859                 xfree(blob);
1860                 return 0;
1861         }
1862         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1863         packet_put_cstring(authctxt->server_user);
1864         packet_put_cstring(authctxt->service);
1865         packet_put_cstring(authctxt->method->name);
1866         packet_put_cstring(pkalg);
1867         packet_put_string(blob, blen);
1868         packet_put_cstring(chost);
1869         packet_put_cstring(authctxt->local_user);
1870         packet_put_string(signature, slen);
1871         memset(signature, 's', slen);
1872         xfree(signature);
1873         xfree(chost);
1874         xfree(pkalg);
1875         xfree(blob);
1876
1877         packet_send();
1878         return 1;
1879 }
1880
1881 #ifdef JPAKE
1882 int
1883 userauth_jpake(Authctxt *authctxt)
1884 {
1885         struct jpake_ctx *pctx;
1886         u_char *x1_proof, *x2_proof;
1887         u_int x1_proof_len, x2_proof_len;
1888         static int attempt = 0; /* XXX share with userauth_password's? */
1889
1890         if (attempt++ >= options.number_of_password_prompts)
1891                 return 0;
1892         if (attempt != 1)
1893                 error("Permission denied, please try again.");
1894
1895         if (authctxt->methoddata != NULL)
1896                 fatal("%s: authctxt->methoddata already set (%p)",
1897                     __func__, authctxt->methoddata);
1898
1899         authctxt->methoddata = pctx = jpake_new();
1900
1901         /*
1902          * Send request immediately, to get the protocol going while
1903          * we do the initial computations.
1904          */
1905         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1906         packet_put_cstring(authctxt->server_user);
1907         packet_put_cstring(authctxt->service);
1908         packet_put_cstring(authctxt->method->name);
1909         packet_send();
1910         packet_write_wait();
1911
1912         jpake_step1(pctx->grp,
1913             &pctx->client_id, &pctx->client_id_len,
1914             &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2,
1915             &x1_proof, &x1_proof_len,
1916             &x2_proof, &x2_proof_len);
1917
1918         JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__));
1919
1920         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1);
1921         packet_put_string(pctx->client_id, pctx->client_id_len);
1922         packet_put_bignum2(pctx->g_x1);
1923         packet_put_bignum2(pctx->g_x2);
1924         packet_put_string(x1_proof, x1_proof_len);
1925         packet_put_string(x2_proof, x2_proof_len);
1926         packet_send();
1927
1928         bzero(x1_proof, x1_proof_len);
1929         bzero(x2_proof, x2_proof_len);
1930         xfree(x1_proof);
1931         xfree(x2_proof);
1932
1933         /* Expect step 1 packet from peer */
1934         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1,
1935             input_userauth_jpake_server_step1);
1936
1937         return 1;
1938 }
1939
1940 void
1941 userauth_jpake_cleanup(Authctxt *authctxt)
1942 {
1943         debug3("%s: clean up", __func__);
1944         if (authctxt->methoddata != NULL) {
1945                 jpake_free(authctxt->methoddata);
1946                 authctxt->methoddata = NULL;
1947         }
1948 }
1949 #endif /* JPAKE */
1950
1951 /* find auth method */
1952
1953 /*
1954  * given auth method name, if configurable options permit this method fill
1955  * in auth_ident field and return true, otherwise return false.
1956  */
1957 static int
1958 authmethod_is_enabled(Authmethod *method)
1959 {
1960         if (method == NULL)
1961                 return 0;
1962         /* return false if options indicate this method is disabled */
1963         if  (method->enabled == NULL || *method->enabled == 0)
1964                 return 0;
1965         /* return false if batch mode is enabled but method needs interactive mode */
1966         if  (method->batch_flag != NULL && *method->batch_flag != 0)
1967                 return 0;
1968         return 1;
1969 }
1970
1971 static Authmethod *
1972 authmethod_lookup(const char *name)
1973 {
1974         Authmethod *method = NULL;
1975         if (name != NULL)
1976                 for (method = authmethods; method->name != NULL; method++)
1977                         if (strcmp(name, method->name) == 0)
1978                                 return method;
1979         debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1980         return NULL;
1981 }
1982
1983 /* XXX internal state */
1984 static Authmethod *current = NULL;
1985 static char *supported = NULL;
1986 static char *preferred = NULL;
1987
1988 /*
1989  * Given the authentication method list sent by the server, return the
1990  * next method we should try.  If the server initially sends a nil list,
1991  * use a built-in default list.
1992  */
1993 static Authmethod *
1994 authmethod_get(char *authlist)
1995 {
1996         char *name = NULL;
1997         u_int next;
1998
1999         /* Use a suitable default if we're passed a nil list.  */
2000         if (authlist == NULL || strlen(authlist) == 0)
2001                 authlist = options.preferred_authentications;
2002
2003         if (supported == NULL || strcmp(authlist, supported) != 0) {
2004                 debug3("start over, passed a different list %s", authlist);
2005                 if (supported != NULL)
2006                         xfree(supported);
2007                 supported = xstrdup(authlist);
2008                 preferred = options.preferred_authentications;
2009                 debug3("preferred %s", preferred);
2010                 current = NULL;
2011         } else if (current != NULL && authmethod_is_enabled(current))
2012                 return current;
2013
2014         for (;;) {
2015                 if ((name = match_list(preferred, supported, &next)) == NULL) {
2016                         debug("No more authentication methods to try.");
2017                         current = NULL;
2018                         return NULL;
2019                 }
2020                 preferred += next;
2021                 debug3("authmethod_lookup %s", name);
2022                 debug3("remaining preferred: %s", preferred);
2023                 if ((current = authmethod_lookup(name)) != NULL &&
2024                     authmethod_is_enabled(current)) {
2025                         debug3("authmethod_is_enabled %s", name);
2026                         debug("Next authentication method: %s", name);
2027                         return current;
2028                 }
2029         }
2030 }
2031
2032 static char *
2033 authmethods_get(void)
2034 {
2035         Authmethod *method = NULL;
2036         Buffer b;
2037         char *list;
2038
2039         buffer_init(&b);
2040         for (method = authmethods; method->name != NULL; method++) {
2041                 if (authmethod_is_enabled(method)) {
2042                         if (buffer_len(&b) > 0)
2043                                 buffer_append(&b, ",", 1);
2044                         buffer_append(&b, method->name, strlen(method->name));
2045                 }
2046         }
2047         buffer_append(&b, "\0", 1);
2048         list = xstrdup(buffer_ptr(&b));
2049         buffer_free(&b);
2050         return list;
2051 }
2052