sshconnect2.c

   1 /* $OpenBSD: sshconnect2.c,v 1.188 2011/05/24 07:15:47 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 <fcntl.h>
  36 #include <netdb.h>
  37 #include <pwd.h>
  38 #include <signal.h>
  39 #include <stdarg.h>
  40 #include <stdio.h>
  41 #include <string.h>
  42 #include <unistd.h>
  43 #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H)
  44 #include <vis.h>
  45 #endif
  46
  47 #include "openbsd-compat/sys-queue.h"
  48
  49 #include "xmalloc.h"
  50 #include "ssh.h"
  51 #include "ssh2.h"
  52 #include "buffer.h"
  53 #include "packet.h"
  54 #include "compat.h"
  55 #include "cipher.h"
  56 #include "key.h"
  57 #include "kex.h"
  58 #include "myproposal.h"
  59 #include "sshconnect.h"
  60 #include "authfile.h"
  61 #include "dh.h"
  62 #include "authfd.h"
  63 #include "log.h"
  64 #include "readconf.h"
  65 #include "misc.h"
  66 #include "match.h"
  67 #include "dispatch.h"
  68 #include "canohost.h"
  69 #include "msg.h"
  70 #include "pathnames.h"
  71 #include "uidswap.h"
  72 #include "hostfile.h"
  73 #include "schnorr.h"
  74 #include "jpake.h"
  75
  76 #ifdef GSSAPI
  77 #include "ssh-gss.h"
  78 #endif
  79
  80 /* import */
  81 extern char *client_version_string;
  82 extern char *server_version_string;
  83 extern Options options;
  84
  85 /*
  86  * SSH2 key exchange
  87  */
  88
  89 u_char *session_id2 = NULL;
  90 u_int session_id2_len = 0;
  91
  92 char *xxx_host;
  93 struct sockaddr *xxx_hostaddr;
  94
  95 Kex *xxx_kex = NULL;
  96
  97 static int
  98 verify_host_key_callback(Key *hostkey)
  99 {
 100         if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
 101                 fatal("Host key verification failed.");
 102         return 0;
 103 }
 104
 105 static char *
 106 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port)
 107 {
 108         char *oavail, *avail, *first, *last, *alg, *hostname, *ret;
 109         size_t maxlen;
 110         struct hostkeys *hostkeys;
 111         int ktype;
 112         u_int i;
 113
 114         /* Find all hostkeys for this hostname */
 115         get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL);
 116         hostkeys = init_hostkeys();
 117         for (i = 0; i < options.num_user_hostfiles; i++)
 118                 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]);
 119         for (i = 0; i < options.num_system_hostfiles; i++)
 120                 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]);
 121
 122         oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG);
 123         maxlen = strlen(avail) + 1;
 124         first = xmalloc(maxlen);
 125         last = xmalloc(maxlen);
 126         *first = *last = '\0';
 127
 128 #define ALG_APPEND(to, from) \
 129         do { \
 130                 if (*to != '\0') \
 131                         strlcat(to, ",", maxlen); \
 132                 strlcat(to, from, maxlen); \
 133         } while (0)
 134
 135         while ((alg = strsep(&avail, ",")) && *alg != '\0') {
 136                 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC)
 137                         fatal("%s: unknown alg %s", __func__, alg);
 138                 if (lookup_key_in_hostkeys_by_type(hostkeys,
 139                     key_type_plain(ktype), NULL))
 140                         ALG_APPEND(first, alg);
 141                 else
 142                         ALG_APPEND(last, alg);
 143         }
 144 #undef ALG_APPEND
 145         xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last);
 146         if (*first != '\0')
 147                 debug3("%s: prefer hostkeyalgs: %s", __func__, first);
 148
 149         xfree(first);
 150         xfree(last);
 151         xfree(hostname);
 152         xfree(oavail);
 153         free_hostkeys(hostkeys);
 154
 155         return ret;
 156 }
 157
 158 void
 159 ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
 160 {
 161         Kex *kex;
 162
 163 #ifdef GSSAPI
 164         char *orig = NULL, *gss = NULL;
 165         char *gss_host = NULL;
 166 #endif
 167
 168         xxx_host = host;
 169         xxx_hostaddr = hostaddr;
 170
 171 #ifdef GSSAPI
 172         if (options.gss_keyex) {
 173                 /* Add the GSSAPI mechanisms currently supported on this
 174                  * client to the key exchange algorithm proposal */
 175                 orig = myproposal[PROPOSAL_KEX_ALGS];
 176
 177                 if (options.gss_trust_dns)
 178                         gss_host = (char *)get_canonical_hostname(1);
 179                 else
 180                         gss_host = host;
 181
 182                 gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity);
 183                 if (gss) {
 184                         debug("Offering GSSAPI proposal: %s", gss);
 185                         xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
 186                             "%s,%s", gss, orig);
 187                 }
 188         }
 189 #endif
 190
 191         if (options.ciphers == (char *)-1) {
 192                 logit("No valid ciphers for protocol version 2 given, using defaults.");
 193                 options.ciphers = NULL;
 194         }
 195         if (options.ciphers != NULL) {
 196                 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 197                 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
 198         }
 199         myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 200             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
 201         myproposal[PROPOSAL_ENC_ALGS_STOC] =
 202             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
 203         if (options.compression) {
 204                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 205                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
 206         } else {
 207                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 208                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
 209         }
 210         if (options.macs != NULL) {
 211                 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
 212                 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
 213         }
 214         if (options.hostkeyalgorithms != NULL)
 215                 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
 216                     options.hostkeyalgorithms;
 217         else {
 218                 /* Prefer algorithms that we already have keys for */
 219                 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
 220                     order_hostkeyalgs(host, hostaddr, port);
 221         }
 222         if (options.kex_algorithms != NULL)
 223                 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms;
 224
 225 #ifdef GSSAPI
 226         /* If we've got GSSAPI algorithms, then we also support the
 227          * 'null' hostkey, as a last resort */
 228         if (options.gss_keyex && gss) {
 229                 orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
 230                 xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],
 231                     "%s,null", orig);
 232                 xfree(gss);
 233         }
 234 #endif
 235
 236         if (options.rekey_limit)
 237                 packet_set_rekey_limit((u_int32_t)options.rekey_limit);
 238
 239         /* start key exchange */
 240         kex = kex_setup(myproposal);
 241         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
 242         kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
 243         kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
 244         kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
 245         kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
 246 #ifdef GSSAPI
 247         if (options.gss_keyex) {
 248                 kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
 249                 kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client;
 250                 kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client;
 251         }
 252 #endif
 253         kex->client_version_string=client_version_string;
 254         kex->server_version_string=server_version_string;
 255         kex->verify_host_key=&verify_host_key_callback;
 256
 257 #ifdef GSSAPI
 258         if (options.gss_keyex) {
 259                 kex->gss_deleg_creds = options.gss_deleg_creds;
 260                 kex->gss_trust_dns = options.gss_trust_dns;
 261                 kex->gss_client = options.gss_client_identity;
 262                 if (options.gss_server_identity) {
 263                         kex->gss_host = options.gss_server_identity;
 264                 } else {
 265                         kex->gss_host = gss_host;
 266         }
 267         }
 268 #endif
 269
 270         xxx_kex = kex;
 271
 272         dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
 273
 274         if (options.use_roaming && !kex->roaming) {
 275                 debug("Roaming not allowed by server");
 276                 options.use_roaming = 0;
 277         }
 278
 279         session_id2 = kex->session_id;
 280         session_id2_len = kex->session_id_len;
 281
 282 #ifdef DEBUG_KEXDH
 283         /* send 1st encrypted/maced/compressed message */
 284         packet_start(SSH2_MSG_IGNORE);
 285         packet_put_cstring("markus");
 286         packet_send();
 287         packet_write_wait();
 288 #endif
 289 }
 290
 291 /*
 292  * Authenticate user
 293  */
 294
 295 typedef struct Authctxt Authctxt;
 296 typedef struct Authmethod Authmethod;
 297 typedef struct identity Identity;
 298 typedef struct idlist Idlist;
 299
 300 struct identity {
 301         TAILQ_ENTRY(identity) next;
 302         AuthenticationConnection *ac;   /* set if agent supports key */
 303         Key     *key;                   /* public/private key */
 304         char    *filename;              /* comment for agent-only keys */
 305         int     tried;
 306         int     isprivate;              /* key points to the private key */
 307 };
 308 TAILQ_HEAD(idlist, identity);
 309
 310 struct Authctxt {
 311         const char *server_user;
 312         const char *local_user;
 313         const char *host;
 314         const char *service;
 315         Authmethod *method;
 316         sig_atomic_t success;
 317         char *authlist;
 318         /* pubkey */
 319         Idlist keys;
 320         AuthenticationConnection *agent;
 321         /* hostbased */
 322         Sensitive *sensitive;
 323         /* kbd-interactive */
 324         int info_req_seen;
 325         /* generic */
 326         void *methoddata;
 327 };
 328 struct Authmethod {
 329         char    *name;          /* string to compare against server's list */
 330         int     (*userauth)(Authctxt *authctxt);
 331         void    (*cleanup)(Authctxt *authctxt);
 332         int     *enabled;       /* flag in option struct that enables method */
 333         int     *batch_flag;    /* flag in option struct that disables method */
 334 };
 335
 336 void    input_userauth_success(int, u_int32_t, void *);
 337 void    input_userauth_success_unexpected(int, u_int32_t, void *);
 338 void    input_userauth_failure(int, u_int32_t, void *);
 339 void    input_userauth_banner(int, u_int32_t, void *);
 340 void    input_userauth_error(int, u_int32_t, void *);
 341 void    input_userauth_info_req(int, u_int32_t, void *);
 342 void    input_userauth_pk_ok(int, u_int32_t, void *);
 343 void    input_userauth_passwd_changereq(int, u_int32_t, void *);
 344 void    input_userauth_jpake_server_step1(int, u_int32_t, void *);
 345 void    input_userauth_jpake_server_step2(int, u_int32_t, void *);
 346 void    input_userauth_jpake_server_confirm(int, u_int32_t, void *);
 347
 348 int     userauth_none(Authctxt *);
 349 int     userauth_pubkey(Authctxt *);
 350 int     userauth_passwd(Authctxt *);
 351 int     userauth_kbdint(Authctxt *);
 352 int     userauth_hostbased(Authctxt *);
 353 int     userauth_jpake(Authctxt *);
 354
 355 void    userauth_jpake_cleanup(Authctxt *);
 356
 357 #ifdef GSSAPI
 358 int     userauth_gssapi(Authctxt *authctxt);
 359 void    input_gssapi_response(int type, u_int32_t, void *);
 360 void    input_gssapi_token(int type, u_int32_t, void *);
 361 void    input_gssapi_hash(int type, u_int32_t, void *);
 362 void    input_gssapi_error(int, u_int32_t, void *);
 363 void    input_gssapi_errtok(int, u_int32_t, void *);
 364 int     userauth_gsskeyex(Authctxt *authctxt);
 365 #endif
 366
 367 void    userauth(Authctxt *, char *);
 368
 369 static int sign_and_send_pubkey(Authctxt *, Identity *);
 370 static void pubkey_prepare(Authctxt *);
 371 static void pubkey_cleanup(Authctxt *);
 372 static Key *load_identity_file(char *);
 373
 374 static Authmethod *authmethod_get(char *authlist);
 375 static Authmethod *authmethod_lookup(const char *name);
 376 static char *authmethods_get(void);
 377
 378 Authmethod authmethods[] = {
 379 #ifdef GSSAPI
 380         {"gssapi-keyex",
 381                 userauth_gsskeyex,
 382                 NULL,
 383                 &options.gss_authentication,
 384                 NULL},
 385         {"gssapi-with-mic",
 386                 userauth_gssapi,
 387                 NULL,
 388                 &options.gss_authentication,
 389                 NULL},
 390 #endif
 391         {"hostbased",
 392                 userauth_hostbased,
 393                 NULL,
 394                 &options.hostbased_authentication,
 395                 NULL},
 396         {"publickey",
 397                 userauth_pubkey,
 398                 NULL,
 399                 &options.pubkey_authentication,
 400                 NULL},
 401 #ifdef JPAKE
 402         {"jpake-01@openssh.com",
 403                 userauth_jpake,
 404                 userauth_jpake_cleanup,
 405                 &options.zero_knowledge_password_authentication,
 406                 &options.batch_mode},
 407 #endif
 408         {"keyboard-interactive",
 409                 userauth_kbdint,
 410                 NULL,
 411                 &options.kbd_interactive_authentication,
 412                 &options.batch_mode},
 413         {"password",
 414                 userauth_passwd,
 415                 NULL,
 416                 &options.password_authentication,
 417                 &options.batch_mode},
 418         {"none",
 419                 userauth_none,
 420                 NULL,
 421                 NULL,
 422                 NULL},
 423         {NULL, NULL, NULL, NULL, NULL}
 424 };
 425
 426 void
 427 ssh_userauth2(const char *local_user, const char *server_user, char *host,
 428     Sensitive *sensitive)
 429 {
 430         Authctxt authctxt;
 431         int type;
 432
 433         if (options.challenge_response_authentication)
 434                 options.kbd_interactive_authentication = 1;
 435
 436         packet_start(SSH2_MSG_SERVICE_REQUEST);
 437         packet_put_cstring("ssh-userauth");
 438         packet_send();
 439         debug("SSH2_MSG_SERVICE_REQUEST sent");
 440         packet_write_wait();
 441         type = packet_read();
 442         if (type != SSH2_MSG_SERVICE_ACCEPT)
 443                 fatal("Server denied authentication request: %d", type);
 444         if (packet_remaining() > 0) {
 445                 char *reply = packet_get_string(NULL);
 446                 debug2("service_accept: %s", reply);
 447                 xfree(reply);
 448         } else {
 449                 debug2("buggy server: service_accept w/o service");
 450         }
 451         packet_check_eom();
 452         debug("SSH2_MSG_SERVICE_ACCEPT received");
 453
 454         if (options.preferred_authentications == NULL)
 455                 options.preferred_authentications = authmethods_get();
 456
 457         /* setup authentication context */
 458         memset(&authctxt, 0, sizeof(authctxt));
 459         pubkey_prepare(&authctxt);
 460         authctxt.server_user = server_user;
 461         authctxt.local_user = local_user;
 462         authctxt.host = host;
 463         authctxt.service = "ssh-connection";            /* service name */
 464         authctxt.success = 0;
 465         authctxt.method = authmethod_lookup("none");
 466         authctxt.authlist = NULL;
 467         authctxt.methoddata = NULL;
 468         authctxt.sensitive = sensitive;
 469         authctxt.info_req_seen = 0;
 470         if (authctxt.method == NULL)
 471                 fatal("ssh_userauth2: internal error: cannot send userauth none request");
 472
 473         /* initial userauth request */
 474         userauth_none(&authctxt);
 475
 476         dispatch_init(&input_userauth_error);
 477         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
 478         dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
 479         dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
 480         dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt);     /* loop until success */
 481
 482         pubkey_cleanup(&authctxt);
 483         dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
 484
 485         debug("Authentication succeeded (%s).", authctxt.method->name);
 486 }
 487
 488 void
 489 userauth(Authctxt *authctxt, char *authlist)
 490 {
 491         if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
 492                 authctxt->method->cleanup(authctxt);
 493
 494         if (authctxt->methoddata) {
 495                 xfree(authctxt->methoddata);
 496                 authctxt->methoddata = NULL;
 497         }
 498         if (authlist == NULL) {
 499                 authlist = authctxt->authlist;
 500         } else {
 501                 if (authctxt->authlist)
 502                         xfree(authctxt->authlist);
 503                 authctxt->authlist = authlist;
 504         }
 505         for (;;) {
 506                 Authmethod *method = authmethod_get(authlist);
 507                 if (method == NULL)
 508                         fatal("Permission denied (%s).", authlist);
 509                 authctxt->method = method;
 510
 511                 /* reset the per method handler */
 512                 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
 513                     SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
 514
 515                 /* and try new method */
 516                 if (method->userauth(authctxt) != 0) {
 517                         debug2("we sent a %s packet, wait for reply", method->name);
 518                         break;
 519                 } else {
 520                         debug2("we did not send a packet, disable method");
 521                         method->enabled = NULL;
 522                 }
 523         }
 524 }
 525
 526 /* ARGSUSED */
 527 void
 528 input_userauth_error(int type, u_int32_t seq, void *ctxt)
 529 {
 530         fatal("input_userauth_error: bad message during authentication: "
 531             "type %d", type);
 532 }
 533
 534 /* ARGSUSED */
 535 void
 536 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
 537 {
 538         char *msg, *raw, *lang;
 539         u_int len;
 540
 541         debug3("input_userauth_banner");
 542         raw = packet_get_string(&len);
 543         lang = packet_get_string(NULL);
 544         if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) {
 545                 if (len > 65536)
 546                         len = 65536;
 547                 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */
 548                 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH);
 549                 fprintf(stderr, "%s", msg);
 550                 xfree(msg);
 551         }
 552         xfree(raw);
 553         xfree(lang);
 554 }
 555
 556 /* ARGSUSED */
 557 void
 558 input_userauth_success(int type, u_int32_t seq, void *ctxt)
 559 {
 560         Authctxt *authctxt = ctxt;
 561
 562         if (authctxt == NULL)
 563                 fatal("input_userauth_success: no authentication context");
 564         if (authctxt->authlist) {
 565                 xfree(authctxt->authlist);
 566                 authctxt->authlist = NULL;
 567         }
 568         if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
 569                 authctxt->method->cleanup(authctxt);
 570         if (authctxt->methoddata) {
 571                 xfree(authctxt->methoddata);
 572                 authctxt->methoddata = NULL;
 573         }
 574         authctxt->success = 1;                  /* break out */
 575 }
 576
 577 void
 578 input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt)
 579 {
 580         Authctxt *authctxt = ctxt;
 581
 582         if (authctxt == NULL)
 583                 fatal("%s: no authentication context", __func__);
 584
 585         fatal("Unexpected authentication success during %s.",
 586             authctxt->method->name);
 587 }
 588
 589 /* ARGSUSED */
 590 void
 591 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
 592 {
 593         Authctxt *authctxt = ctxt;
 594         char *authlist = NULL;
 595         int partial;
 596
 597         if (authctxt == NULL)
 598                 fatal("input_userauth_failure: no authentication context");
 599
 600         authlist = packet_get_string(NULL);
 601         partial = packet_get_char();
 602         packet_check_eom();
 603
 604         if (partial != 0)
 605                 logit("Authenticated with partial success.");
 606         debug("Authentications that can continue: %s", authlist);
 607
 608         userauth(authctxt, authlist);
 609 }
 610
 611 /* ARGSUSED */
 612 void
 613 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
 614 {
 615         Authctxt *authctxt = ctxt;
 616         Key *key = NULL;
 617         Identity *id = NULL;
 618         Buffer b;
 619         int pktype, sent = 0;
 620         u_int alen, blen;
 621         char *pkalg, *fp;
 622         u_char *pkblob;
 623
 624         if (authctxt == NULL)
 625                 fatal("input_userauth_pk_ok: no authentication context");
 626         if (datafellows & SSH_BUG_PKOK) {
 627                 /* this is similar to SSH_BUG_PKAUTH */
 628                 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
 629                 pkblob = packet_get_string(&blen);
 630                 buffer_init(&b);
 631                 buffer_append(&b, pkblob, blen);
 632                 pkalg = buffer_get_string(&b, &alen);
 633                 buffer_free(&b);
 634         } else {
 635                 pkalg = packet_get_string(&alen);
 636                 pkblob = packet_get_string(&blen);
 637         }
 638         packet_check_eom();
 639
 640         debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
 641
 642         if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
 643                 debug("unknown pkalg %s", pkalg);
 644                 goto done;
 645         }
 646         if ((key = key_from_blob(pkblob, blen)) == NULL) {
 647                 debug("no key from blob. pkalg %s", pkalg);
 648                 goto done;
 649         }
 650         if (key->type != pktype) {
 651                 error("input_userauth_pk_ok: type mismatch "
 652                     "for decoded key (received %d, expected %d)",
 653                     key->type, pktype);
 654                 goto done;
 655         }
 656         fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
 657         debug2("input_userauth_pk_ok: fp %s", fp);
 658         xfree(fp);
 659
 660         /*
 661          * search keys in the reverse order, because last candidate has been
 662          * moved to the end of the queue.  this also avoids confusion by
 663          * duplicate keys
 664          */
 665         TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
 666                 if (key_equal(key, id->key)) {
 667                         sent = sign_and_send_pubkey(authctxt, id);
 668                         break;
 669                 }
 670         }
 671 done:
 672         if (key != NULL)
 673                 key_free(key);
 674         xfree(pkalg);
 675         xfree(pkblob);
 676
 677         /* try another method if we did not send a packet */
 678         if (sent == 0)
 679                 userauth(authctxt, NULL);
 680 }
 681
 682 #ifdef GSSAPI
 683 int
 684 userauth_gssapi(Authctxt *authctxt)
 685 {
 686         Gssctxt *gssctxt = NULL;
 687         static gss_OID_set gss_supported = NULL;
 688         static u_int mech = 0;
 689         OM_uint32 min;
 690         int ok = 0;
 691         const char *gss_host;
 692
 693         if (options.gss_server_identity)
 694                 gss_host = options.gss_server_identity;
 695         else if (options.gss_trust_dns)
 696                 gss_host = get_canonical_hostname(1);
 697         else
 698                 gss_host = authctxt->host;
 699
 700         /* Try one GSSAPI method at a time, rather than sending them all at
 701          * once. */
 702
 703         if (gss_supported == NULL)
 704                 if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) {
 705                         gss_supported = NULL;
 706                         return 0;
 707                 }
 708
 709         /* Check to see if the mechanism is usable before we offer it */
 710         while (mech < gss_supported->count && !ok) {
 711                 /* My DER encoding requires length<128 */
 712                 if (gss_supported->elements[mech].length < 128 &&
 713                     ssh_gssapi_check_mechanism(&gssctxt,
 714                     &gss_supported->elements[mech], gss_host,
 715                     options.gss_client_identity)) {
 716                         ok = 1; /* Mechanism works */
 717                 } else {
 718                         mech++;
 719                 }
 720         }
 721
 722         if (!ok)
 723                 return 0;
 724
 725         authctxt->methoddata=(void *)gssctxt;
 726
 727         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 728         packet_put_cstring(authctxt->server_user);
 729         packet_put_cstring(authctxt->service);
 730         packet_put_cstring(authctxt->method->name);
 731
 732         packet_put_int(1);
 733
 734         packet_put_int((gss_supported->elements[mech].length) + 2);
 735         packet_put_char(SSH_GSS_OIDTYPE);
 736         packet_put_char(gss_supported->elements[mech].length);
 737         packet_put_raw(gss_supported->elements[mech].elements,
 738             gss_supported->elements[mech].length);
 739
 740         packet_send();
 741
 742         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
 743         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
 744         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
 745         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
 746
 747         mech++; /* Move along to next candidate */
 748
 749         return 1;
 750 }
 751
 752 static OM_uint32
 753 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
 754 {
 755         Authctxt *authctxt = ctxt;
 756         Gssctxt *gssctxt = authctxt->methoddata;
 757         gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
 758         gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
 759         gss_buffer_desc gssbuf;
 760         OM_uint32 status, ms, flags;
 761         Buffer b;
 762
 763         status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
 764             recv_tok, &send_tok, &flags);
 765
 766         if (send_tok.length > 0) {
 767                 if (GSS_ERROR(status))
 768                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
 769                 else
 770                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
 771
 772                 packet_put_string(send_tok.value, send_tok.length);
 773                 packet_send();
 774                 gss_release_buffer(&ms, &send_tok);
 775         }
 776
 777         if (status == GSS_S_COMPLETE) {
 778                 /* send either complete or MIC, depending on mechanism */
 779                 if (!(flags & GSS_C_INTEG_FLAG)) {
 780                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
 781                         packet_send();
 782                 } else {
 783                         ssh_gssapi_buildmic(&b, authctxt->server_user,
 784                             authctxt->service, "gssapi-with-mic");
 785
 786                         gssbuf.value = buffer_ptr(&b);
 787                         gssbuf.length = buffer_len(&b);
 788
 789                         status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
 790
 791                         if (!GSS_ERROR(status)) {
 792                                 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
 793                                 packet_put_string(mic.value, mic.length);
 794
 795                                 packet_send();
 796                         }
 797
 798                         buffer_free(&b);
 799                         gss_release_buffer(&ms, &mic);
 800                 }
 801         }
 802
 803         return status;
 804 }
 805
 806 /* ARGSUSED */
 807 void
 808 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
 809 {
 810         Authctxt *authctxt = ctxt;
 811         Gssctxt *gssctxt;
 812         u_int oidlen;
 813         u_char *oidv;
 814
 815         if (authctxt == NULL)
 816                 fatal("input_gssapi_response: no authentication context");
 817         gssctxt = authctxt->methoddata;
 818
 819         /* Setup our OID */
 820         oidv = packet_get_string(&oidlen);
 821
 822         if (oidlen <= 2 ||
 823             oidv[0] != SSH_GSS_OIDTYPE ||
 824             oidv[1] != oidlen - 2) {
 825                 xfree(oidv);
 826                 debug("Badly encoded mechanism OID received");
 827                 userauth(authctxt, NULL);
 828                 return;
 829         }
 830
 831         if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
 832                 fatal("Server returned different OID than expected");
 833
 834         packet_check_eom();
 835
 836         xfree(oidv);
 837
 838         if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
 839                 /* Start again with next method on list */
 840                 debug("Trying to start again");
 841                 userauth(authctxt, NULL);
 842                 return;
 843         }
 844 }
 845
 846 /* ARGSUSED */
 847 void
 848 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
 849 {
 850         Authctxt *authctxt = ctxt;
 851         gss_buffer_desc recv_tok;
 852         OM_uint32 status;
 853         u_int slen;
 854
 855         if (authctxt == NULL)
 856                 fatal("input_gssapi_response: no authentication context");
 857
 858         recv_tok.value = packet_get_string(&slen);
 859         recv_tok.length = slen; /* safe typecast */
 860
 861         packet_check_eom();
 862
 863         status = process_gssapi_token(ctxt, &recv_tok);
 864
 865         xfree(recv_tok.value);
 866
 867         if (GSS_ERROR(status)) {
 868                 /* Start again with the next method in the list */
 869                 userauth(authctxt, NULL);
 870                 return;
 871         }
 872 }
 873
 874 /* ARGSUSED */
 875 void
 876 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
 877 {
 878         Authctxt *authctxt = ctxt;
 879         Gssctxt *gssctxt;
 880         gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
 881         gss_buffer_desc recv_tok;
 882         OM_uint32 status, ms;
 883         u_int len;
 884
 885         if (authctxt == NULL)
 886                 fatal("input_gssapi_response: no authentication context");
 887         gssctxt = authctxt->methoddata;
 888
 889         recv_tok.value = packet_get_string(&len);
 890         recv_tok.length = len;
 891
 892         packet_check_eom();
 893
 894         /* Stick it into GSSAPI and see what it says */
 895         status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
 896             &recv_tok, &send_tok, NULL);
 897
 898         xfree(recv_tok.value);
 899         gss_release_buffer(&ms, &send_tok);
 900
 901         /* Server will be returning a failed packet after this one */
 902 }
 903
 904 /* ARGSUSED */
 905 void
 906 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
 907 {
 908         OM_uint32 maj, min;
 909         char *msg;
 910         char *lang;
 911
 912         maj=packet_get_int();
 913         min=packet_get_int();
 914         msg=packet_get_string(NULL);
 915         lang=packet_get_string(NULL);
 916
 917         packet_check_eom();
 918
 919         debug("Server GSSAPI Error:\n%s", msg);
 920         xfree(msg);
 921         xfree(lang);
 922 }
 923
 924 int
 925 userauth_gsskeyex(Authctxt *authctxt)
 926 {
 927         Buffer b;
 928         gss_buffer_desc gssbuf;
 929         gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
 930         OM_uint32 ms;
 931
 932         static int attempt = 0;
 933         if (attempt++ >= 1)
 934                 return (0);
 935
 936         if (gss_kex_context == NULL) {
 937                 debug("No valid Key exchange context");
 938                 return (0);
 939         }
 940
 941         ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service,
 942             "gssapi-keyex");
 943
 944         gssbuf.value = buffer_ptr(&b);
 945         gssbuf.length = buffer_len(&b);
 946
 947         if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) {
 948                 buffer_free(&b);
 949                 return (0);
 950         }
 951
 952         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 953         packet_put_cstring(authctxt->server_user);
 954         packet_put_cstring(authctxt->service);
 955         packet_put_cstring(authctxt->method->name);
 956         packet_put_string(mic.value, mic.length);
 957         packet_send();
 958
 959         buffer_free(&b);
 960         gss_release_buffer(&ms, &mic);
 961
 962         return (1);
 963 }
 964
 965 #endif /* GSSAPI */
 966
 967 int
 968 userauth_none(Authctxt *authctxt)
 969 {
 970         /* initial userauth request */
 971         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 972         packet_put_cstring(authctxt->server_user);
 973         packet_put_cstring(authctxt->service);
 974         packet_put_cstring(authctxt->method->name);
 975         packet_send();
 976         return 1;
 977 }
 978
 979 int
 980 userauth_passwd(Authctxt *authctxt)
 981 {
 982         static int attempt = 0;
 983         char prompt[150];
 984         char *password;
 985         const char *host = options.host_key_alias ?  options.host_key_alias :
 986             authctxt->host;
 987
 988         if (attempt++ >= options.number_of_password_prompts)
 989                 return 0;
 990
 991         if (attempt != 1)
 992                 error("Permission denied, please try again.");
 993
 994         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
 995             authctxt->server_user, host);
 996         password = read_passphrase(prompt, 0);
 997         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 998         packet_put_cstring(authctxt->server_user);
 999         packet_put_cstring(authctxt->service);
1000         packet_put_cstring(authctxt->method->name);
1001         packet_put_char(0);
1002         packet_put_cstring(password);
1003         memset(password, 0, strlen(password));
1004         xfree(password);
1005         packet_add_padding(64);
1006         packet_send();
1007
1008         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
1009             &input_userauth_passwd_changereq);
1010
1011         return 1;
1012 }
1013
1014 /*
1015  * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
1016  */
1017 /* ARGSUSED */
1018 void
1019 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
1020 {
1021         Authctxt *authctxt = ctxt;
1022         char *info, *lang, *password = NULL, *retype = NULL;
1023         char prompt[150];
1024         const char *host = options.host_key_alias ? options.host_key_alias :
1025             authctxt->host;
1026
1027         debug2("input_userauth_passwd_changereq");
1028
1029         if (authctxt == NULL)
1030                 fatal("input_userauth_passwd_changereq: "
1031                     "no authentication context");
1032
1033         info = packet_get_string(NULL);
1034         lang = packet_get_string(NULL);
1035         if (strlen(info) > 0)
1036                 logit("%s", info);
1037         xfree(info);
1038         xfree(lang);
1039         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1040         packet_put_cstring(authctxt->server_user);
1041         packet_put_cstring(authctxt->service);
1042         packet_put_cstring(authctxt->method->name);
1043         packet_put_char(1);                     /* additional info */
1044         snprintf(prompt, sizeof(prompt),
1045             "Enter %.30s@%.128s's old password: ",
1046             authctxt->server_user, host);
1047         password = read_passphrase(prompt, 0);
1048         packet_put_cstring(password);
1049         memset(password, 0, strlen(password));
1050         xfree(password);
1051         password = NULL;
1052         while (password == NULL) {
1053                 snprintf(prompt, sizeof(prompt),
1054                     "Enter %.30s@%.128s's new password: ",
1055                     authctxt->server_user, host);
1056                 password = read_passphrase(prompt, RP_ALLOW_EOF);
1057                 if (password == NULL) {
1058                         /* bail out */
1059                         return;
1060                 }
1061                 snprintf(prompt, sizeof(prompt),
1062                     "Retype %.30s@%.128s's new password: ",
1063                     authctxt->server_user, host);
1064                 retype = read_passphrase(prompt, 0);
1065                 if (strcmp(password, retype) != 0) {
1066                         memset(password, 0, strlen(password));
1067                         xfree(password);
1068                         logit("Mismatch; try again, EOF to quit.");
1069                         password = NULL;
1070                 }
1071                 memset(retype, 0, strlen(retype));
1072                 xfree(retype);
1073         }
1074         packet_put_cstring(password);
1075         memset(password, 0, strlen(password));
1076         xfree(password);
1077         packet_add_padding(64);
1078         packet_send();
1079
1080         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
1081             &input_userauth_passwd_changereq);
1082 }
1083
1084 #ifdef JPAKE
1085 static char *
1086 pw_encrypt(const char *password, const char *crypt_scheme, const char *salt)
1087 {
1088         /* OpenBSD crypt(3) handles all of these */
1089         if (strcmp(crypt_scheme, "crypt") == 0 ||
1090             strcmp(crypt_scheme, "bcrypt") == 0 ||
1091             strcmp(crypt_scheme, "md5crypt") == 0 ||
1092             strcmp(crypt_scheme, "crypt-extended") == 0)
1093                 return xstrdup(crypt(password, salt));
1094         error("%s: unsupported password encryption scheme \"%.100s\"",
1095             __func__, crypt_scheme);
1096         return NULL;
1097 }
1098
1099 static BIGNUM *
1100 jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme,
1101     const char *salt)
1102 {
1103         char prompt[256], *password, *crypted;
1104         u_char *secret;
1105         u_int secret_len;
1106         BIGNUM *ret;
1107
1108         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ",
1109             authctxt->server_user, authctxt->host);
1110         password = read_passphrase(prompt, 0);
1111
1112         if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) {
1113                 logit("Disabling %s authentication", authctxt->method->name);
1114                 authctxt->method->enabled = NULL;
1115                 /* Continue with an empty password to fail gracefully */
1116                 crypted = xstrdup("");
1117         }
1118
1119 #ifdef JPAKE_DEBUG
1120         debug3("%s: salt = %s", __func__, salt);
1121         debug3("%s: scheme = %s", __func__, crypt_scheme);
1122         debug3("%s: crypted = %s", __func__, crypted);
1123 #endif
1124
1125         if (hash_buffer(crypted, strlen(crypted), EVP_sha256(),
1126             &secret, &secret_len) != 0)
1127                 fatal("%s: hash_buffer", __func__);
1128
1129         bzero(password, strlen(password));
1130         bzero(crypted, strlen(crypted));
1131         xfree(password);
1132         xfree(crypted);
1133
1134         if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL)
1135                 fatal("%s: BN_bin2bn (secret)", __func__);
1136         bzero(secret, secret_len);
1137         xfree(secret);
1138
1139         return ret;
1140 }
1141
1142 /* ARGSUSED */
1143 void
1144 input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt)
1145 {
1146         Authctxt *authctxt = ctxt;
1147         struct jpake_ctx *pctx = authctxt->methoddata;
1148         u_char *x3_proof, *x4_proof, *x2_s_proof;
1149         u_int x3_proof_len, x4_proof_len, x2_s_proof_len;
1150         char *crypt_scheme, *salt;
1151
1152         /* Disable this message */
1153         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL);
1154
1155         if ((pctx->g_x3 = BN_new()) == NULL ||
1156             (pctx->g_x4 = BN_new()) == NULL)
1157                 fatal("%s: BN_new", __func__);
1158
1159         /* Fetch step 1 values */
1160         crypt_scheme = packet_get_string(NULL);
1161         salt = packet_get_string(NULL);
1162         pctx->server_id = packet_get_string(&pctx->server_id_len);
1163         packet_get_bignum2(pctx->g_x3);
1164         packet_get_bignum2(pctx->g_x4);
1165         x3_proof = packet_get_string(&x3_proof_len);
1166         x4_proof = packet_get_string(&x4_proof_len);
1167         packet_check_eom();
1168
1169         JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__));
1170
1171         /* Obtain password and derive secret */
1172         pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt);
1173         bzero(crypt_scheme, strlen(crypt_scheme));
1174         bzero(salt, strlen(salt));
1175         xfree(crypt_scheme);
1176         xfree(salt);
1177         JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__));
1178
1179         /* Calculate step 2 values */
1180         jpake_step2(pctx->grp, pctx->s, pctx->g_x1,
1181             pctx->g_x3, pctx->g_x4, pctx->x2,
1182             pctx->server_id, pctx->server_id_len,
1183             pctx->client_id, pctx->client_id_len,
1184             x3_proof, x3_proof_len,
1185             x4_proof, x4_proof_len,
1186             &pctx->a,
1187             &x2_s_proof, &x2_s_proof_len);
1188
1189         bzero(x3_proof, x3_proof_len);
1190         bzero(x4_proof, x4_proof_len);
1191         xfree(x3_proof);
1192         xfree(x4_proof);
1193
1194         JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__));
1195
1196         /* Send values for step 2 */
1197         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2);
1198         packet_put_bignum2(pctx->a);
1199         packet_put_string(x2_s_proof, x2_s_proof_len);
1200         packet_send();
1201
1202         bzero(x2_s_proof, x2_s_proof_len);
1203         xfree(x2_s_proof);
1204
1205         /* Expect step 2 packet from peer */
1206         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2,
1207             input_userauth_jpake_server_step2);
1208 }
1209
1210 /* ARGSUSED */
1211 void
1212 input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt)
1213 {
1214         Authctxt *authctxt = ctxt;
1215         struct jpake_ctx *pctx = authctxt->methoddata;
1216         u_char *x4_s_proof;
1217         u_int x4_s_proof_len;
1218
1219         /* Disable this message */
1220         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL);
1221
1222         if ((pctx->b = BN_new()) == NULL)
1223                 fatal("%s: BN_new", __func__);
1224
1225         /* Fetch step 2 values */
1226         packet_get_bignum2(pctx->b);
1227         x4_s_proof = packet_get_string(&x4_s_proof_len);
1228         packet_check_eom();
1229
1230         JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__));
1231
1232         /* Derive shared key and calculate confirmation hash */
1233         jpake_key_confirm(pctx->grp, pctx->s, pctx->b,
1234             pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4,
1235             pctx->client_id, pctx->client_id_len,
1236             pctx->server_id, pctx->server_id_len,
1237             session_id2, session_id2_len,
1238             x4_s_proof, x4_s_proof_len,
1239             &pctx->k,
1240             &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len);
1241
1242         bzero(x4_s_proof, x4_s_proof_len);
1243         xfree(x4_s_proof);
1244
1245         JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__));
1246
1247         /* Send key confirmation proof */
1248         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM);
1249         packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len);
1250         packet_send();
1251
1252         /* Expect confirmation from peer */
1253         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM,
1254             input_userauth_jpake_server_confirm);
1255 }
1256
1257 /* ARGSUSED */
1258 void
1259 input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt)
1260 {
1261         Authctxt *authctxt = ctxt;
1262         struct jpake_ctx *pctx = authctxt->methoddata;
1263
1264         /* Disable this message */
1265         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL);
1266
1267         pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len);
1268         packet_check_eom();
1269
1270         JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__));
1271
1272         /* Verify expected confirmation hash */
1273         if (jpake_check_confirm(pctx->k,
1274             pctx->server_id, pctx->server_id_len,
1275             session_id2, session_id2_len,
1276             pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1)
1277                 debug("%s: %s success", __func__, authctxt->method->name);
1278         else {
1279                 debug("%s: confirmation mismatch", __func__);
1280                 /* XXX stash this so if auth succeeds then we can warn/kill */
1281         }
1282
1283         userauth_jpake_cleanup(authctxt);
1284 }
1285 #endif /* JPAKE */
1286
1287 static int
1288 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
1289     u_char *data, u_int datalen)
1290 {
1291         Key *prv;
1292         int ret;
1293
1294         /* the agent supports this key */
1295         if (id->ac)
1296                 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
1297                     data, datalen));
1298         /*
1299          * we have already loaded the private key or
1300          * the private key is stored in external hardware
1301          */
1302         if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
1303                 return (key_sign(id->key, sigp, lenp, data, datalen));
1304         /* load the private key from the file */
1305         if ((prv = load_identity_file(id->filename)) == NULL)
1306                 return (-1);
1307         ret = key_sign(prv, sigp, lenp, data, datalen);
1308         key_free(prv);
1309         return (ret);
1310 }
1311
1312 static int
1313 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
1314 {
1315         Buffer b;
1316         u_char *blob, *signature;
1317         u_int bloblen, slen;
1318         u_int skip = 0;
1319         int ret = -1;
1320         int have_sig = 1;
1321         char *fp;
1322
1323         fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
1324         debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp);
1325         xfree(fp);
1326
1327         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1328                 /* we cannot handle this key */
1329                 debug3("sign_and_send_pubkey: cannot handle key");
1330                 return 0;
1331         }
1332         /* data to be signed */
1333         buffer_init(&b);
1334         if (datafellows & SSH_OLD_SESSIONID) {
1335                 buffer_append(&b, session_id2, session_id2_len);
1336                 skip = session_id2_len;
1337         } else {
1338                 buffer_put_string(&b, session_id2, session_id2_len);
1339                 skip = buffer_len(&b);
1340         }
1341         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1342         buffer_put_cstring(&b, authctxt->server_user);
1343         buffer_put_cstring(&b,
1344             datafellows & SSH_BUG_PKSERVICE ?
1345             "ssh-userauth" :
1346             authctxt->service);
1347         if (datafellows & SSH_BUG_PKAUTH) {
1348                 buffer_put_char(&b, have_sig);
1349         } else {
1350                 buffer_put_cstring(&b, authctxt->method->name);
1351                 buffer_put_char(&b, have_sig);
1352                 buffer_put_cstring(&b, key_ssh_name(id->key));
1353         }
1354         buffer_put_string(&b, blob, bloblen);
1355
1356         /* generate signature */
1357         ret = identity_sign(id, &signature, &slen,
1358             buffer_ptr(&b), buffer_len(&b));
1359         if (ret == -1) {
1360                 xfree(blob);
1361                 buffer_free(&b);
1362                 return 0;
1363         }
1364 #ifdef DEBUG_PK
1365         buffer_dump(&b);
1366 #endif
1367         if (datafellows & SSH_BUG_PKSERVICE) {
1368                 buffer_clear(&b);
1369                 buffer_append(&b, session_id2, session_id2_len);
1370                 skip = session_id2_len;
1371                 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1372                 buffer_put_cstring(&b, authctxt->server_user);
1373                 buffer_put_cstring(&b, authctxt->service);
1374                 buffer_put_cstring(&b, authctxt->method->name);
1375                 buffer_put_char(&b, have_sig);
1376                 if (!(datafellows & SSH_BUG_PKAUTH))
1377                         buffer_put_cstring(&b, key_ssh_name(id->key));
1378                 buffer_put_string(&b, blob, bloblen);
1379         }
1380         xfree(blob);
1381
1382         /* append signature */
1383         buffer_put_string(&b, signature, slen);
1384         xfree(signature);
1385
1386         /* skip session id and packet type */
1387         if (buffer_len(&b) < skip + 1)
1388                 fatal("userauth_pubkey: internal error");
1389         buffer_consume(&b, skip + 1);
1390
1391         /* put remaining data from buffer into packet */
1392         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1393         packet_put_raw(buffer_ptr(&b), buffer_len(&b));
1394         buffer_free(&b);
1395         packet_send();
1396
1397         return 1;
1398 }
1399
1400 static int
1401 send_pubkey_test(Authctxt *authctxt, Identity *id)
1402 {
1403         u_char *blob;
1404         u_int bloblen, have_sig = 0;
1405
1406         debug3("send_pubkey_test");
1407
1408         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1409                 /* we cannot handle this key */
1410                 debug3("send_pubkey_test: cannot handle key");
1411                 return 0;
1412         }
1413         /* register callback for USERAUTH_PK_OK message */
1414         dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
1415
1416         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1417         packet_put_cstring(authctxt->server_user);
1418         packet_put_cstring(authctxt->service);
1419         packet_put_cstring(authctxt->method->name);
1420         packet_put_char(have_sig);
1421         if (!(datafellows & SSH_BUG_PKAUTH))
1422                 packet_put_cstring(key_ssh_name(id->key));
1423         packet_put_string(blob, bloblen);
1424         xfree(blob);
1425         packet_send();
1426         return 1;
1427 }
1428
1429 static Key *
1430 load_identity_file(char *filename)
1431 {
1432         Key *private;
1433         char prompt[300], *passphrase;
1434         int perm_ok = 0, quit, i;
1435         struct stat st;
1436
1437         if (stat(filename, &st) < 0) {
1438                 debug3("no such identity: %s", filename);
1439                 return NULL;
1440         }
1441         private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
1442         if (!perm_ok)
1443                 return NULL;
1444         if (private == NULL) {
1445                 if (options.batch_mode)
1446                         return NULL;
1447                 snprintf(prompt, sizeof prompt,
1448                     "Enter passphrase for key '%.100s': ", filename);
1449                 for (i = 0; i < options.number_of_password_prompts; i++) {
1450                         passphrase = read_passphrase(prompt, 0);
1451                         if (strcmp(passphrase, "") != 0) {
1452                                 private = key_load_private_type(KEY_UNSPEC,
1453                                     filename, passphrase, NULL, NULL);
1454                                 quit = 0;
1455                         } else {
1456                                 debug2("no passphrase given, try next key");
1457                                 quit = 1;
1458                         }
1459                         memset(passphrase, 0, strlen(passphrase));
1460                         xfree(passphrase);
1461                         if (private != NULL || quit)
1462                                 break;
1463                         debug2("bad passphrase given, try again...");
1464                 }
1465         }
1466         return private;
1467 }
1468
1469 /*
1470  * try keys in the following order:
1471  *      1. agent keys that are found in the config file
1472  *      2. other agent keys
1473  *      3. keys that are only listed in the config file
1474  */
1475 static void
1476 pubkey_prepare(Authctxt *authctxt)
1477 {
1478         Identity *id;
1479         Idlist agent, files, *preferred;
1480         Key *key;
1481         AuthenticationConnection *ac;
1482         char *comment;
1483         int i, found;
1484
1485         TAILQ_INIT(&agent);     /* keys from the agent */
1486         TAILQ_INIT(&files);     /* keys from the config file */
1487         preferred = &authctxt->keys;
1488         TAILQ_INIT(preferred);  /* preferred order of keys */
1489
1490         /* list of keys stored in the filesystem */
1491         for (i = 0; i < options.num_identity_files; i++) {
1492                 key = options.identity_keys[i];
1493                 if (key && key->type == KEY_RSA1)
1494                         continue;
1495                 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER)
1496                         continue;
1497                 options.identity_keys[i] = NULL;
1498                 id = xcalloc(1, sizeof(*id));
1499                 id->key = key;
1500                 id->filename = xstrdup(options.identity_files[i]);
1501                 TAILQ_INSERT_TAIL(&files, id, next);
1502         }
1503         /* list of keys supported by the agent */
1504         if ((ac = ssh_get_authentication_connection())) {
1505                 for (key = ssh_get_first_identity(ac, &comment, 2);
1506                     key != NULL;
1507                     key = ssh_get_next_identity(ac, &comment, 2)) {
1508                         found = 0;
1509                         TAILQ_FOREACH(id, &files, next) {
1510                                 /* agent keys from the config file are preferred */
1511                                 if (key_equal(key, id->key)) {
1512                                         key_free(key);
1513                                         xfree(comment);
1514                                         TAILQ_REMOVE(&files, id, next);
1515                                         TAILQ_INSERT_TAIL(preferred, id, next);
1516                                         id->ac = ac;
1517                                         found = 1;
1518                                         break;
1519                                 }
1520                         }
1521                         if (!found && !options.identities_only) {
1522                                 id = xcalloc(1, sizeof(*id));
1523                                 id->key = key;
1524                                 id->filename = comment;
1525                                 id->ac = ac;
1526                                 TAILQ_INSERT_TAIL(&agent, id, next);
1527                         }
1528                 }
1529                 /* append remaining agent keys */
1530                 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1531                         TAILQ_REMOVE(&agent, id, next);
1532                         TAILQ_INSERT_TAIL(preferred, id, next);
1533                 }
1534                 authctxt->agent = ac;
1535         }
1536         /* append remaining keys from the config file */
1537         for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1538                 TAILQ_REMOVE(&files, id, next);
1539                 TAILQ_INSERT_TAIL(preferred, id, next);
1540         }
1541         TAILQ_FOREACH(id, preferred, next) {
1542                 debug2("key: %s (%p)", id->filename, id->key);
1543         }
1544 }
1545
1546 static void
1547 pubkey_cleanup(Authctxt *authctxt)
1548 {
1549         Identity *id;
1550
1551         if (authctxt->agent != NULL)
1552                 ssh_close_authentication_connection(authctxt->agent);
1553         for (id = TAILQ_FIRST(&authctxt->keys); id;
1554             id = TAILQ_FIRST(&authctxt->keys)) {
1555                 TAILQ_REMOVE(&authctxt->keys, id, next);
1556                 if (id->key)
1557                         key_free(id->key);
1558                 if (id->filename)
1559                         xfree(id->filename);
1560                 xfree(id);
1561         }
1562 }
1563
1564 int
1565 userauth_pubkey(Authctxt *authctxt)
1566 {
1567         Identity *id;
1568         int sent = 0;
1569
1570         while ((id = TAILQ_FIRST(&authctxt->keys))) {
1571                 if (id->tried++)
1572                         return (0);
1573                 /* move key to the end of the queue */
1574                 TAILQ_REMOVE(&authctxt->keys, id, next);
1575                 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1576                 /*
1577                  * send a test message if we have the public key. for
1578                  * encrypted keys we cannot do this and have to load the
1579                  * private key instead
1580                  */
1581                 if (id->key && id->key->type != KEY_RSA1) {
1582                         debug("Offering %s public key: %s", key_type(id->key),
1583                             id->filename);
1584                         sent = send_pubkey_test(authctxt, id);
1585                 } else if (id->key == NULL) {
1586                         debug("Trying private key: %s", id->filename);
1587                         id->key = load_identity_file(id->filename);
1588                         if (id->key != NULL) {
1589                                 id->isprivate = 1;
1590                                 sent = sign_and_send_pubkey(authctxt, id);
1591                                 key_free(id->key);
1592                                 id->key = NULL;
1593                         }
1594                 }
1595                 if (sent)
1596                         return (sent);
1597         }
1598         return (0);
1599 }
1600
1601 /*
1602  * Send userauth request message specifying keyboard-interactive method.
1603  */
1604 int
1605 userauth_kbdint(Authctxt *authctxt)
1606 {
1607         static int attempt = 0;
1608
1609         if (attempt++ >= options.number_of_password_prompts)
1610                 return 0;
1611         /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1612         if (attempt > 1 && !authctxt->info_req_seen) {
1613                 debug3("userauth_kbdint: disable: no info_req_seen");
1614                 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1615                 return 0;
1616         }
1617
1618         debug2("userauth_kbdint");
1619         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1620         packet_put_cstring(authctxt->server_user);
1621         packet_put_cstring(authctxt->service);
1622         packet_put_cstring(authctxt->method->name);
1623         packet_put_cstring("");                                 /* lang */
1624         packet_put_cstring(options.kbd_interactive_devices ?
1625             options.kbd_interactive_devices : "");
1626         packet_send();
1627
1628         dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1629         return 1;
1630 }
1631
1632 /*
1633  * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1634  */
1635 void
1636 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1637 {
1638         Authctxt *authctxt = ctxt;
1639         char *name, *inst, *lang, *prompt, *response;
1640         u_int num_prompts, i;
1641         int echo = 0;
1642
1643         debug2("input_userauth_info_req");
1644
1645         if (authctxt == NULL)
1646                 fatal("input_userauth_info_req: no authentication context");
1647
1648         authctxt->info_req_seen = 1;
1649
1650         name = packet_get_string(NULL);
1651         inst = packet_get_string(NULL);
1652         lang = packet_get_string(NULL);
1653         if (strlen(name) > 0)
1654                 logit("%s", name);
1655         if (strlen(inst) > 0)
1656                 logit("%s", inst);
1657         xfree(name);
1658         xfree(inst);
1659         xfree(lang);
1660
1661         num_prompts = packet_get_int();
1662         /*
1663          * Begin to build info response packet based on prompts requested.
1664          * We commit to providing the correct number of responses, so if
1665          * further on we run into a problem that prevents this, we have to
1666          * be sure and clean this up and send a correct error response.
1667          */
1668         packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1669         packet_put_int(num_prompts);
1670
1671         debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1672         for (i = 0; i < num_prompts; i++) {
1673                 prompt = packet_get_string(NULL);
1674                 echo = packet_get_char();
1675
1676                 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1677
1678                 packet_put_cstring(response);
1679                 memset(response, 0, strlen(response));
1680                 xfree(response);
1681                 xfree(prompt);
1682         }
1683         packet_check_eom(); /* done with parsing incoming message. */
1684
1685         packet_add_padding(64);
1686         packet_send();
1687 }
1688
1689 static int
1690 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1691     u_char *data, u_int datalen)
1692 {
1693         Buffer b;
1694         struct stat st;
1695         pid_t pid;
1696         int to[2], from[2], status, version = 2;
1697
1698         debug2("ssh_keysign called");
1699
1700         if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1701                 error("ssh_keysign: not installed: %s", strerror(errno));
1702                 return -1;
1703         }
1704         if (fflush(stdout) != 0)
1705                 error("ssh_keysign: fflush: %s", strerror(errno));
1706         if (pipe(to) < 0) {
1707                 error("ssh_keysign: pipe: %s", strerror(errno));
1708                 return -1;
1709         }
1710         if (pipe(from) < 0) {
1711                 error("ssh_keysign: pipe: %s", strerror(errno));
1712                 return -1;
1713         }
1714         if ((pid = fork()) < 0) {
1715                 error("ssh_keysign: fork: %s", strerror(errno));
1716                 return -1;
1717         }
1718         if (pid == 0) {
1719                 /* keep the socket on exec */
1720                 fcntl(packet_get_connection_in(), F_SETFD, 0);
1721                 permanently_drop_suid(getuid());
1722                 close(from[0]);
1723                 if (dup2(from[1], STDOUT_FILENO) < 0)
1724                         fatal("ssh_keysign: dup2: %s", strerror(errno));
1725                 close(to[1]);
1726                 if (dup2(to[0], STDIN_FILENO) < 0)
1727                         fatal("ssh_keysign: dup2: %s", strerror(errno));
1728                 close(from[1]);
1729                 close(to[0]);
1730                 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1731                 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1732                     strerror(errno));
1733         }
1734         close(from[1]);
1735         close(to[0]);
1736
1737         buffer_init(&b);
1738         buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1739         buffer_put_string(&b, data, datalen);
1740         if (ssh_msg_send(to[1], version, &b) == -1)
1741                 fatal("ssh_keysign: couldn't send request");
1742
1743         if (ssh_msg_recv(from[0], &b) < 0) {
1744                 error("ssh_keysign: no reply");
1745                 buffer_free(&b);
1746                 return -1;
1747         }
1748         close(from[0]);
1749         close(to[1]);
1750
1751         while (waitpid(pid, &status, 0) < 0)
1752                 if (errno != EINTR)
1753                         break;
1754
1755         if (buffer_get_char(&b) != version) {
1756                 error("ssh_keysign: bad version");
1757                 buffer_free(&b);
1758                 return -1;
1759         }
1760         *sigp = buffer_get_string(&b, lenp);
1761         buffer_free(&b);
1762
1763         return 0;
1764 }
1765
1766 int
1767 userauth_hostbased(Authctxt *authctxt)
1768 {
1769         Key *private = NULL;
1770         Sensitive *sensitive = authctxt->sensitive;
1771         Buffer b;
1772         u_char *signature, *blob;
1773         char *chost, *pkalg, *p;
1774         const char *service;
1775         u_int blen, slen;
1776         int ok, i, found = 0;
1777
1778         /* check for a useful key */
1779         for (i = 0; i < sensitive->nkeys; i++) {
1780                 private = sensitive->keys[i];
1781                 if (private && private->type != KEY_RSA1) {
1782                         found = 1;
1783                         /* we take and free the key */
1784                         sensitive->keys[i] = NULL;
1785                         break;
1786                 }
1787         }
1788         if (!found) {
1789                 debug("No more client hostkeys for hostbased authentication.");
1790                 return 0;
1791         }
1792         if (key_to_blob(private, &blob, &blen) == 0) {
1793                 key_free(private);
1794                 return 0;
1795         }
1796         /* figure out a name for the client host */
1797         p = get_local_name(packet_get_connection_in());
1798         if (p == NULL) {
1799                 error("userauth_hostbased: cannot get local ipaddr/name");
1800                 key_free(private);
1801                 xfree(blob);
1802                 return 0;
1803         }
1804         xasprintf(&chost, "%s.", p);
1805         debug2("userauth_hostbased: chost %s", chost);
1806         xfree(p);
1807
1808         service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1809             authctxt->service;
1810         pkalg = xstrdup(key_ssh_name(private));
1811         buffer_init(&b);
1812         /* construct data */
1813         buffer_put_string(&b, session_id2, session_id2_len);
1814         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1815         buffer_put_cstring(&b, authctxt->server_user);
1816         buffer_put_cstring(&b, service);
1817         buffer_put_cstring(&b, authctxt->method->name);
1818         buffer_put_cstring(&b, pkalg);
1819         buffer_put_string(&b, blob, blen);
1820         buffer_put_cstring(&b, chost);
1821         buffer_put_cstring(&b, authctxt->local_user);
1822 #ifdef DEBUG_PK
1823         buffer_dump(&b);
1824 #endif
1825         if (sensitive->external_keysign)
1826                 ok = ssh_keysign(private, &signature, &slen,
1827                     buffer_ptr(&b), buffer_len(&b));
1828         else
1829                 ok = key_sign(private, &signature, &slen,
1830                     buffer_ptr(&b), buffer_len(&b));
1831         key_free(private);
1832         buffer_free(&b);
1833         if (ok != 0) {
1834                 error("key_sign failed");
1835                 xfree(chost);
1836                 xfree(pkalg);
1837                 xfree(blob);
1838                 return 0;
1839         }
1840         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1841         packet_put_cstring(authctxt->server_user);
1842         packet_put_cstring(authctxt->service);
1843         packet_put_cstring(authctxt->method->name);
1844         packet_put_cstring(pkalg);
1845         packet_put_string(blob, blen);
1846         packet_put_cstring(chost);
1847         packet_put_cstring(authctxt->local_user);
1848         packet_put_string(signature, slen);
1849         memset(signature, 's', slen);
1850         xfree(signature);
1851         xfree(chost);
1852         xfree(pkalg);
1853         xfree(blob);
1854
1855         packet_send();
1856         return 1;
1857 }
1858
1859 #ifdef JPAKE
1860 int
1861 userauth_jpake(Authctxt *authctxt)
1862 {
1863         struct jpake_ctx *pctx;
1864         u_char *x1_proof, *x2_proof;
1865         u_int x1_proof_len, x2_proof_len;
1866         static int attempt = 0; /* XXX share with userauth_password's? */
1867
1868         if (attempt++ >= options.number_of_password_prompts)
1869                 return 0;
1870         if (attempt != 1)
1871                 error("Permission denied, please try again.");
1872
1873         if (authctxt->methoddata != NULL)
1874                 fatal("%s: authctxt->methoddata already set (%p)",
1875                     __func__, authctxt->methoddata);
1876
1877         authctxt->methoddata = pctx = jpake_new();
1878
1879         /*
1880          * Send request immediately, to get the protocol going while
1881          * we do the initial computations.
1882          */
1883         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1884         packet_put_cstring(authctxt->server_user);
1885         packet_put_cstring(authctxt->service);
1886         packet_put_cstring(authctxt->method->name);
1887         packet_send();
1888         packet_write_wait();
1889
1890         jpake_step1(pctx->grp,
1891             &pctx->client_id, &pctx->client_id_len,
1892             &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2,
1893             &x1_proof, &x1_proof_len,
1894             &x2_proof, &x2_proof_len);
1895
1896         JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__));
1897
1898         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1);
1899         packet_put_string(pctx->client_id, pctx->client_id_len);
1900         packet_put_bignum2(pctx->g_x1);
1901         packet_put_bignum2(pctx->g_x2);
1902         packet_put_string(x1_proof, x1_proof_len);
1903         packet_put_string(x2_proof, x2_proof_len);
1904         packet_send();
1905
1906         bzero(x1_proof, x1_proof_len);
1907         bzero(x2_proof, x2_proof_len);
1908         xfree(x1_proof);
1909         xfree(x2_proof);
1910
1911         /* Expect step 1 packet from peer */
1912         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1,
1913             input_userauth_jpake_server_step1);
1914         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS,
1915             &input_userauth_success_unexpected);
1916
1917         return 1;
1918 }
1919
1920 void
1921 userauth_jpake_cleanup(Authctxt *authctxt)
1922 {
1923         debug3("%s: clean up", __func__);
1924         if (authctxt->methoddata != NULL) {
1925                 jpake_free(authctxt->methoddata);
1926                 authctxt->methoddata = NULL;
1927         }
1928         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
1929 }
1930 #endif /* JPAKE */
1931
1932 /* find auth method */
1933
1934 /*
1935  * given auth method name, if configurable options permit this method fill
1936  * in auth_ident field and return true, otherwise return false.
1937  */
1938 static int
1939 authmethod_is_enabled(Authmethod *method)
1940 {
1941         if (method == NULL)
1942                 return 0;
1943         /* return false if options indicate this method is disabled */
1944         if  (method->enabled == NULL || *method->enabled == 0)
1945                 return 0;
1946         /* return false if batch mode is enabled but method needs interactive mode */
1947         if  (method->batch_flag != NULL && *method->batch_flag != 0)
1948                 return 0;
1949         return 1;
1950 }
1951
1952 static Authmethod *
1953 authmethod_lookup(const char *name)
1954 {
1955         Authmethod *method = NULL;
1956         if (name != NULL)
1957                 for (method = authmethods; method->name != NULL; method++)
1958                         if (strcmp(name, method->name) == 0)
1959                                 return method;
1960         debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1961         return NULL;
1962 }
1963
1964 /* XXX internal state */
1965 static Authmethod *current = NULL;
1966 static char *supported = NULL;
1967 static char *preferred = NULL;
1968
1969 /*
1970  * Given the authentication method list sent by the server, return the
1971  * next method we should try.  If the server initially sends a nil list,
1972  * use a built-in default list.
1973  */
1974 static Authmethod *
1975 authmethod_get(char *authlist)
1976 {
1977         char *name = NULL;
1978         u_int next;
1979
1980         /* Use a suitable default if we're passed a nil list.  */
1981         if (authlist == NULL || strlen(authlist) == 0)
1982                 authlist = options.preferred_authentications;
1983
1984         if (supported == NULL || strcmp(authlist, supported) != 0) {
1985                 debug3("start over, passed a different list %s", authlist);
1986                 if (supported != NULL)
1987                         xfree(supported);
1988                 supported = xstrdup(authlist);
1989                 preferred = options.preferred_authentications;
1990                 debug3("preferred %s", preferred);
1991                 current = NULL;
1992         } else if (current != NULL && authmethod_is_enabled(current))
1993                 return current;
1994
1995         for (;;) {
1996                 if ((name = match_list(preferred, supported, &next)) == NULL) {
1997                         debug("No more authentication methods to try.");
1998                         current = NULL;
1999                         return NULL;
2000                 }
2001                 preferred += next;
2002                 debug3("authmethod_lookup %s", name);
2003                 debug3("remaining preferred: %s", preferred);
2004                 if ((current = authmethod_lookup(name)) != NULL &&
2005                     authmethod_is_enabled(current)) {
2006                         debug3("authmethod_is_enabled %s", name);
2007                         debug("Next authentication method: %s", name);
2008                         xfree(name);
2009                         return current;
2010                 }
2011         }
2012         if (name != NULL)
2013                 xfree(name);
2014 }
2015
2016 static char *
2017 authmethods_get(void)
2018 {
2019         Authmethod *method = NULL;
2020         Buffer b;
2021         char *list;
2022
2023         buffer_init(&b);
2024         for (method = authmethods; method->name != NULL; method++) {
2025                 if (authmethod_is_enabled(method)) {
2026                         if (buffer_len(&b) > 0)
2027                                 buffer_append(&b, ",", 1);
2028                         buffer_append(&b, method->name, strlen(method->name));
2029                 }
2030         }
2031         buffer_append(&b, "\0", 1);
2032         list = xstrdup(buffer_ptr(&b));
2033         buffer_free(&b);
2034         return list;
2035 }
2036