crypto/openssh/sshconnect2.c

   1 /* $OpenBSD: sshconnect2.c,v 1.201 2014/01/09 23:20:00 djm Exp $ */
   2 /* $FreeBSD$ */
   3 /*
   4  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   5  * Copyright (c) 2008 Damien Miller.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "includes.h"
  29
  30 #include <sys/types.h>
  31 #include <sys/socket.h>
  32 #include <sys/wait.h>
  33 #include <sys/stat.h>
  34
  35 #include <errno.h>
  36 #include <fcntl.h>
  37 #include <netdb.h>
  38 #include <pwd.h>
  39 #include <signal.h>
  40 #include <stdarg.h>
  41 #include <stdio.h>
  42 #include <string.h>
  43 #include <unistd.h>
  44 #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS)
  45 #include <vis.h>
  46 #endif
  47
  48 #include "openbsd-compat/sys-queue.h"
  49
  50 #include "xmalloc.h"
  51 #include "ssh.h"
  52 #include "ssh2.h"
  53 #include "buffer.h"
  54 #include "packet.h"
  55 #include "compat.h"
  56 #include "cipher.h"
  57 #include "key.h"
  58 #include "kex.h"
  59 #include "myproposal.h"
  60 #include "sshconnect.h"
  61 #include "authfile.h"
  62 #include "dh.h"
  63 #include "authfd.h"
  64 #include "log.h"
  65 #include "readconf.h"
  66 #include "misc.h"
  67 #include "match.h"
  68 #include "dispatch.h"
  69 #include "canohost.h"
  70 #include "msg.h"
  71 #include "pathnames.h"
  72 #include "uidswap.h"
  73 #include "hostfile.h"
  74 #include "schnorr.h"
  75 #include "jpake.h"
  76
  77 #ifdef GSSAPI
  78 #include "ssh-gss.h"
  79 #endif
  80
  81 /* import */
  82 extern char *client_version_string;
  83 extern char *server_version_string;
  84 extern Options options;
  85 #ifdef  NONE_CIPHER_ENABLED
  86 extern Kex *xxx_kex;
  87
  88 /*
  89  * tty_flag is set in ssh.c so we can use it here.  If set then prevent
  90  * the switch to the null cipher.
  91  */
  92
  93 extern int tty_flag;
  94 #endif
  95
  96 /*
  97  * SSH2 key exchange
  98  */
  99
 100 u_char *session_id2 = NULL;
 101 u_int session_id2_len = 0;
 102
 103 char *xxx_host;
 104 struct sockaddr *xxx_hostaddr;
 105
 106 Kex *xxx_kex = NULL;
 107
 108 static int
 109 verify_host_key_callback(Key *hostkey)
 110 {
 111         if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
 112                 fatal("Host key verification failed.");
 113         return 0;
 114 }
 115
 116 static char *
 117 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port)
 118 {
 119         char *oavail, *avail, *first, *last, *alg, *hostname, *ret;
 120         size_t maxlen;
 121         struct hostkeys *hostkeys;
 122         int ktype;
 123         u_int i;
 124
 125         /* Find all hostkeys for this hostname */
 126         get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL);
 127         hostkeys = init_hostkeys();
 128         for (i = 0; i < options.num_user_hostfiles; i++)
 129                 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]);
 130         for (i = 0; i < options.num_system_hostfiles; i++)
 131                 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]);
 132
 133         oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG);
 134         maxlen = strlen(avail) + 1;
 135         first = xmalloc(maxlen);
 136         last = xmalloc(maxlen);
 137         *first = *last = '\0';
 138
 139 #define ALG_APPEND(to, from) \
 140         do { \
 141                 if (*to != '\0') \
 142                         strlcat(to, ",", maxlen); \
 143                 strlcat(to, from, maxlen); \
 144         } while (0)
 145
 146         while ((alg = strsep(&avail, ",")) && *alg != '\0') {
 147                 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC)
 148                         fatal("%s: unknown alg %s", __func__, alg);
 149                 if (lookup_key_in_hostkeys_by_type(hostkeys,
 150                     key_type_plain(ktype), NULL))
 151                         ALG_APPEND(first, alg);
 152                 else
 153                         ALG_APPEND(last, alg);
 154         }
 155 #undef ALG_APPEND
 156         xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last);
 157         if (*first != '\0')
 158                 debug3("%s: prefer hostkeyalgs: %s", __func__, first);
 159
 160         free(first);
 161         free(last);
 162         free(hostname);
 163         free(oavail);
 164         free_hostkeys(hostkeys);
 165
 166         return ret;
 167 }
 168
 169 void
 170 ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
 171 {
 172         Kex *kex;
 173
 174         xxx_host = host;
 175         xxx_hostaddr = hostaddr;
 176
 177         if (options.ciphers == (char *)-1) {
 178                 logit("No valid ciphers for protocol version 2 given, using defaults.");
 179                 options.ciphers = NULL;
 180         }
 181         if (options.ciphers != NULL) {
 182                 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 183                 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
 184         }
 185         myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 186             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
 187         myproposal[PROPOSAL_ENC_ALGS_STOC] =
 188             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
 189         if (options.compression) {
 190                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 191                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
 192         } else {
 193                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 194                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
 195         }
 196         if (options.macs != NULL) {
 197                 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
 198                 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
 199         }
 200         if (options.hostkeyalgorithms != NULL)
 201                 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
 202                     compat_pkalg_proposal(options.hostkeyalgorithms);
 203         else {
 204                 /* Prefer algorithms that we already have keys for */
 205                 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
 206                     compat_pkalg_proposal(
 207                     order_hostkeyalgs(host, hostaddr, port));
 208         }
 209         if (options.kex_algorithms != NULL)
 210                 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms;
 211
 212         if (options.rekey_limit || options.rekey_interval)
 213                 packet_set_rekey_limits((u_int32_t)options.rekey_limit,
 214                     (time_t)options.rekey_interval);
 215
 216         /* start key exchange */
 217         kex = kex_setup(myproposal);
 218         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
 219         kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
 220         kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
 221         kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
 222         kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
 223         kex->kex[KEX_C25519_SHA256] = kexc25519_client;
 224         kex->client_version_string=client_version_string;
 225         kex->server_version_string=server_version_string;
 226         kex->verify_host_key=&verify_host_key_callback;
 227
 228         xxx_kex = kex;
 229
 230         dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
 231
 232         if (options.use_roaming && !kex->roaming) {
 233                 debug("Roaming not allowed by server");
 234                 options.use_roaming = 0;
 235         }
 236
 237         session_id2 = kex->session_id;
 238         session_id2_len = kex->session_id_len;
 239
 240 #ifdef DEBUG_KEXDH
 241         /* send 1st encrypted/maced/compressed message */
 242         packet_start(SSH2_MSG_IGNORE);
 243         packet_put_cstring("markus");
 244         packet_send();
 245         packet_write_wait();
 246 #endif
 247 }
 248
 249 /*
 250  * Authenticate user
 251  */
 252
 253 typedef struct Authctxt Authctxt;
 254 typedef struct Authmethod Authmethod;
 255 typedef struct identity Identity;
 256 typedef struct idlist Idlist;
 257
 258 struct identity {
 259         TAILQ_ENTRY(identity) next;
 260         AuthenticationConnection *ac;   /* set if agent supports key */
 261         Key     *key;                   /* public/private key */
 262         char    *filename;              /* comment for agent-only keys */
 263         int     tried;
 264         int     isprivate;              /* key points to the private key */
 265         int     userprovided;
 266 };
 267 TAILQ_HEAD(idlist, identity);
 268
 269 struct Authctxt {
 270         const char *server_user;
 271         const char *local_user;
 272         const char *host;
 273         const char *service;
 274         Authmethod *method;
 275         sig_atomic_t success;
 276         char *authlist;
 277         /* pubkey */
 278         Idlist keys;
 279         AuthenticationConnection *agent;
 280         /* hostbased */
 281         Sensitive *sensitive;
 282         /* kbd-interactive */
 283         int info_req_seen;
 284         /* generic */
 285         void *methoddata;
 286 };
 287 struct Authmethod {
 288         char    *name;          /* string to compare against server's list */
 289         int     (*userauth)(Authctxt *authctxt);
 290         void    (*cleanup)(Authctxt *authctxt);
 291         int     *enabled;       /* flag in option struct that enables method */
 292         int     *batch_flag;    /* flag in option struct that disables method */
 293 };
 294
 295 void    input_userauth_success(int, u_int32_t, void *);
 296 void    input_userauth_success_unexpected(int, u_int32_t, void *);
 297 void    input_userauth_failure(int, u_int32_t, void *);
 298 void    input_userauth_banner(int, u_int32_t, void *);
 299 void    input_userauth_error(int, u_int32_t, void *);
 300 void    input_userauth_info_req(int, u_int32_t, void *);
 301 void    input_userauth_pk_ok(int, u_int32_t, void *);
 302 void    input_userauth_passwd_changereq(int, u_int32_t, void *);
 303 void    input_userauth_jpake_server_step1(int, u_int32_t, void *);
 304 void    input_userauth_jpake_server_step2(int, u_int32_t, void *);
 305 void    input_userauth_jpake_server_confirm(int, u_int32_t, void *);
 306
 307 int     userauth_none(Authctxt *);
 308 int     userauth_pubkey(Authctxt *);
 309 int     userauth_passwd(Authctxt *);
 310 int     userauth_kbdint(Authctxt *);
 311 int     userauth_hostbased(Authctxt *);
 312 int     userauth_jpake(Authctxt *);
 313
 314 void    userauth_jpake_cleanup(Authctxt *);
 315
 316 #ifdef GSSAPI
 317 int     userauth_gssapi(Authctxt *authctxt);
 318 void    input_gssapi_response(int type, u_int32_t, void *);
 319 void    input_gssapi_token(int type, u_int32_t, void *);
 320 void    input_gssapi_hash(int type, u_int32_t, void *);
 321 void    input_gssapi_error(int, u_int32_t, void *);
 322 void    input_gssapi_errtok(int, u_int32_t, void *);
 323 #endif
 324
 325 void    userauth(Authctxt *, char *);
 326
 327 static int sign_and_send_pubkey(Authctxt *, Identity *);
 328 static void pubkey_prepare(Authctxt *);
 329 static void pubkey_cleanup(Authctxt *);
 330 static Key *load_identity_file(char *, int);
 331
 332 static Authmethod *authmethod_get(char *authlist);
 333 static Authmethod *authmethod_lookup(const char *name);
 334 static char *authmethods_get(void);
 335
 336 Authmethod authmethods[] = {
 337 #ifdef GSSAPI
 338         {"gssapi-with-mic",
 339                 userauth_gssapi,
 340                 NULL,
 341                 &options.gss_authentication,
 342                 NULL},
 343 #endif
 344         {"hostbased",
 345                 userauth_hostbased,
 346                 NULL,
 347                 &options.hostbased_authentication,
 348                 NULL},
 349         {"publickey",
 350                 userauth_pubkey,
 351                 NULL,
 352                 &options.pubkey_authentication,
 353                 NULL},
 354 #ifdef JPAKE
 355         {"jpake-01@openssh.com",
 356                 userauth_jpake,
 357                 userauth_jpake_cleanup,
 358                 &options.zero_knowledge_password_authentication,
 359                 &options.batch_mode},
 360 #endif
 361         {"keyboard-interactive",
 362                 userauth_kbdint,
 363                 NULL,
 364                 &options.kbd_interactive_authentication,
 365                 &options.batch_mode},
 366         {"password",
 367                 userauth_passwd,
 368                 NULL,
 369                 &options.password_authentication,
 370                 &options.batch_mode},
 371         {"none",
 372                 userauth_none,
 373                 NULL,
 374                 NULL,
 375                 NULL},
 376         {NULL, NULL, NULL, NULL, NULL}
 377 };
 378
 379 void
 380 ssh_userauth2(const char *local_user, const char *server_user, char *host,
 381     Sensitive *sensitive)
 382 {
 383         Authctxt authctxt;
 384         int type;
 385
 386         if (options.challenge_response_authentication)
 387                 options.kbd_interactive_authentication = 1;
 388
 389         packet_start(SSH2_MSG_SERVICE_REQUEST);
 390         packet_put_cstring("ssh-userauth");
 391         packet_send();
 392         debug("SSH2_MSG_SERVICE_REQUEST sent");
 393         packet_write_wait();
 394         type = packet_read();
 395         if (type != SSH2_MSG_SERVICE_ACCEPT)
 396                 fatal("Server denied authentication request: %d", type);
 397         if (packet_remaining() > 0) {
 398                 char *reply = packet_get_string(NULL);
 399                 debug2("service_accept: %s", reply);
 400                 free(reply);
 401         } else {
 402                 debug2("buggy server: service_accept w/o service");
 403         }
 404         packet_check_eom();
 405         debug("SSH2_MSG_SERVICE_ACCEPT received");
 406
 407         if (options.preferred_authentications == NULL)
 408                 options.preferred_authentications = authmethods_get();
 409
 410         /* setup authentication context */
 411         memset(&authctxt, 0, sizeof(authctxt));
 412         pubkey_prepare(&authctxt);
 413         authctxt.server_user = server_user;
 414         authctxt.local_user = local_user;
 415         authctxt.host = host;
 416         authctxt.service = "ssh-connection";            /* service name */
 417         authctxt.success = 0;
 418         authctxt.method = authmethod_lookup("none");
 419         authctxt.authlist = NULL;
 420         authctxt.methoddata = NULL;
 421         authctxt.sensitive = sensitive;
 422         authctxt.info_req_seen = 0;
 423         if (authctxt.method == NULL)
 424                 fatal("ssh_userauth2: internal error: cannot send userauth none request");
 425
 426         /* initial userauth request */
 427         userauth_none(&authctxt);
 428
 429         dispatch_init(&input_userauth_error);
 430         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
 431         dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
 432         dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
 433         dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt);     /* loop until success */
 434
 435         pubkey_cleanup(&authctxt);
 436         dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
 437
 438 #ifdef  NONE_CIPHER_ENABLED
 439         /*
 440          * If the user explicitly requests to use the none cipher enable it
 441          * post authentication and only if the right conditions are met: both
 442          * of the NONE switches must be true and there must be no tty allocated.
 443          */
 444         if (options.none_switch == 1 && options.none_enabled == 1) {
 445                 if (!tty_flag) {
 446                         debug("Requesting none cipher re-keying...");
 447                         myproposal[PROPOSAL_ENC_ALGS_STOC] = "none";
 448                         myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none";
 449                         kex_prop2buf(&xxx_kex->my, myproposal);
 450                         packet_request_rekeying();
 451                         fprintf(stderr, "WARNING: enabled NONE cipher\n");
 452                 } else {
 453                         /* Requested NONE cipher on an interactive session. */
 454                         debug("Cannot switch to NONE cipher with tty "
 455                             "allocated");
 456                         fprintf(stderr, "NONE cipher switch disabled given "
 457                             "a TTY is allocated\n");
 458                 }
 459         }
 460 #endif
 461         debug("Authentication succeeded (%s).", authctxt.method->name);
 462 }
 463
 464 void
 465 userauth(Authctxt *authctxt, char *authlist)
 466 {
 467         if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
 468                 authctxt->method->cleanup(authctxt);
 469
 470         free(authctxt->methoddata);
 471         authctxt->methoddata = NULL;
 472         if (authlist == NULL) {
 473                 authlist = authctxt->authlist;
 474         } else {
 475                 free(authctxt->authlist);
 476                 authctxt->authlist = authlist;
 477         }
 478         for (;;) {
 479                 Authmethod *method = authmethod_get(authlist);
 480                 if (method == NULL)
 481                         fatal("Permission denied (%s).", authlist);
 482                 authctxt->method = method;
 483
 484                 /* reset the per method handler */
 485                 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
 486                     SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
 487
 488                 /* and try new method */
 489                 if (method->userauth(authctxt) != 0) {
 490                         debug2("we sent a %s packet, wait for reply", method->name);
 491                         break;
 492                 } else {
 493                         debug2("we did not send a packet, disable method");
 494                         method->enabled = NULL;
 495                 }
 496         }
 497 }
 498
 499 /* ARGSUSED */
 500 void
 501 input_userauth_error(int type, u_int32_t seq, void *ctxt)
 502 {
 503         fatal("input_userauth_error: bad message during authentication: "
 504             "type %d", type);
 505 }
 506
 507 /* ARGSUSED */
 508 void
 509 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
 510 {
 511         char *msg, *raw, *lang;
 512         u_int len;
 513
 514         debug3("input_userauth_banner");
 515         raw = packet_get_string(&len);
 516         lang = packet_get_string(NULL);
 517         if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) {
 518                 if (len > 65536)
 519                         len = 65536;
 520                 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */
 521                 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH);
 522                 fprintf(stderr, "%s", msg);
 523                 free(msg);
 524         }
 525         free(raw);
 526         free(lang);
 527 }
 528
 529 /* ARGSUSED */
 530 void
 531 input_userauth_success(int type, u_int32_t seq, void *ctxt)
 532 {
 533         Authctxt *authctxt = ctxt;
 534
 535         if (authctxt == NULL)
 536                 fatal("input_userauth_success: no authentication context");
 537         free(authctxt->authlist);
 538         authctxt->authlist = NULL;
 539         if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
 540                 authctxt->method->cleanup(authctxt);
 541         free(authctxt->methoddata);
 542         authctxt->methoddata = NULL;
 543         authctxt->success = 1;                  /* break out */
 544 }
 545
 546 void
 547 input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt)
 548 {
 549         Authctxt *authctxt = ctxt;
 550
 551         if (authctxt == NULL)
 552                 fatal("%s: no authentication context", __func__);
 553
 554         fatal("Unexpected authentication success during %s.",
 555             authctxt->method->name);
 556 }
 557
 558 /* ARGSUSED */
 559 void
 560 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
 561 {
 562         Authctxt *authctxt = ctxt;
 563         char *authlist = NULL;
 564         int partial;
 565
 566         if (authctxt == NULL)
 567                 fatal("input_userauth_failure: no authentication context");
 568
 569         authlist = packet_get_string(NULL);
 570         partial = packet_get_char();
 571         packet_check_eom();
 572
 573         if (partial != 0) {
 574                 logit("Authenticated with partial success.");
 575                 /* reset state */
 576                 pubkey_cleanup(authctxt);
 577                 pubkey_prepare(authctxt);
 578         }
 579         debug("Authentications that can continue: %s", authlist);
 580
 581         userauth(authctxt, authlist);
 582 }
 583
 584 /* ARGSUSED */
 585 void
 586 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
 587 {
 588         Authctxt *authctxt = ctxt;
 589         Key *key = NULL;
 590         Identity *id = NULL;
 591         Buffer b;
 592         int pktype, sent = 0;
 593         u_int alen, blen;
 594         char *pkalg, *fp;
 595         u_char *pkblob;
 596
 597         if (authctxt == NULL)
 598                 fatal("input_userauth_pk_ok: no authentication context");
 599         if (datafellows & SSH_BUG_PKOK) {
 600                 /* this is similar to SSH_BUG_PKAUTH */
 601                 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
 602                 pkblob = packet_get_string(&blen);
 603                 buffer_init(&b);
 604                 buffer_append(&b, pkblob, blen);
 605                 pkalg = buffer_get_string(&b, &alen);
 606                 buffer_free(&b);
 607         } else {
 608                 pkalg = packet_get_string(&alen);
 609                 pkblob = packet_get_string(&blen);
 610         }
 611         packet_check_eom();
 612
 613         debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
 614
 615         if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
 616                 debug("unknown pkalg %s", pkalg);
 617                 goto done;
 618         }
 619         if ((key = key_from_blob(pkblob, blen)) == NULL) {
 620                 debug("no key from blob. pkalg %s", pkalg);
 621                 goto done;
 622         }
 623         if (key->type != pktype) {
 624                 error("input_userauth_pk_ok: type mismatch "
 625                     "for decoded key (received %d, expected %d)",
 626                     key->type, pktype);
 627                 goto done;
 628         }
 629         fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
 630         debug2("input_userauth_pk_ok: fp %s", fp);
 631         free(fp);
 632
 633         /*
 634          * search keys in the reverse order, because last candidate has been
 635          * moved to the end of the queue.  this also avoids confusion by
 636          * duplicate keys
 637          */
 638         TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
 639                 if (key_equal(key, id->key)) {
 640                         sent = sign_and_send_pubkey(authctxt, id);
 641                         break;
 642                 }
 643         }
 644 done:
 645         if (key != NULL)
 646                 key_free(key);
 647         free(pkalg);
 648         free(pkblob);
 649
 650         /* try another method if we did not send a packet */
 651         if (sent == 0)
 652                 userauth(authctxt, NULL);
 653 }
 654
 655 #ifdef GSSAPI
 656 int
 657 userauth_gssapi(Authctxt *authctxt)
 658 {
 659         Gssctxt *gssctxt = NULL;
 660         static gss_OID_set gss_supported = NULL;
 661         static u_int mech = 0;
 662         OM_uint32 min;
 663         int ok = 0;
 664
 665         /* Try one GSSAPI method at a time, rather than sending them all at
 666          * once. */
 667
 668         if (gss_supported == NULL)
 669                 gss_indicate_mechs(&min, &gss_supported);
 670
 671         /* Check to see if the mechanism is usable before we offer it */
 672         while (mech < gss_supported->count && !ok) {
 673                 /* My DER encoding requires length<128 */
 674                 if (gss_supported->elements[mech].length < 128 &&
 675                     ssh_gssapi_check_mechanism(&gssctxt,
 676                     &gss_supported->elements[mech], authctxt->host)) {
 677                         ok = 1; /* Mechanism works */
 678                 } else {
 679                         mech++;
 680                 }
 681         }
 682
 683         if (!ok)
 684                 return 0;
 685
 686         authctxt->methoddata=(void *)gssctxt;
 687
 688         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 689         packet_put_cstring(authctxt->server_user);
 690         packet_put_cstring(authctxt->service);
 691         packet_put_cstring(authctxt->method->name);
 692
 693         packet_put_int(1);
 694
 695         packet_put_int((gss_supported->elements[mech].length) + 2);
 696         packet_put_char(SSH_GSS_OIDTYPE);
 697         packet_put_char(gss_supported->elements[mech].length);
 698         packet_put_raw(gss_supported->elements[mech].elements,
 699             gss_supported->elements[mech].length);
 700
 701         packet_send();
 702
 703         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
 704         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
 705         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
 706         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
 707
 708         mech++; /* Move along to next candidate */
 709
 710         return 1;
 711 }
 712
 713 static OM_uint32
 714 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
 715 {
 716         Authctxt *authctxt = ctxt;
 717         Gssctxt *gssctxt = authctxt->methoddata;
 718         gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
 719         gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
 720         gss_buffer_desc gssbuf;
 721         OM_uint32 status, ms, flags;
 722         Buffer b;
 723
 724         status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
 725             recv_tok, &send_tok, &flags);
 726
 727         if (send_tok.length > 0) {
 728                 if (GSS_ERROR(status))
 729                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
 730                 else
 731                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
 732
 733                 packet_put_string(send_tok.value, send_tok.length);
 734                 packet_send();
 735                 gss_release_buffer(&ms, &send_tok);
 736         }
 737
 738         if (status == GSS_S_COMPLETE) {
 739                 /* send either complete or MIC, depending on mechanism */
 740                 if (!(flags & GSS_C_INTEG_FLAG)) {
 741                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
 742                         packet_send();
 743                 } else {
 744                         ssh_gssapi_buildmic(&b, authctxt->server_user,
 745                             authctxt->service, "gssapi-with-mic");
 746
 747                         gssbuf.value = buffer_ptr(&b);
 748                         gssbuf.length = buffer_len(&b);
 749
 750                         status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
 751
 752                         if (!GSS_ERROR(status)) {
 753                                 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
 754                                 packet_put_string(mic.value, mic.length);
 755
 756                                 packet_send();
 757                         }
 758
 759                         buffer_free(&b);
 760                         gss_release_buffer(&ms, &mic);
 761                 }
 762         }
 763
 764         return status;
 765 }
 766
 767 /* ARGSUSED */
 768 void
 769 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
 770 {
 771         Authctxt *authctxt = ctxt;
 772         Gssctxt *gssctxt;
 773         int oidlen;
 774         char *oidv;
 775
 776         if (authctxt == NULL)
 777                 fatal("input_gssapi_response: no authentication context");
 778         gssctxt = authctxt->methoddata;
 779
 780         /* Setup our OID */
 781         oidv = packet_get_string(&oidlen);
 782
 783         if (oidlen <= 2 ||
 784             oidv[0] != SSH_GSS_OIDTYPE ||
 785             oidv[1] != oidlen - 2) {
 786                 free(oidv);
 787                 debug("Badly encoded mechanism OID received");
 788                 userauth(authctxt, NULL);
 789                 return;
 790         }
 791
 792         if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
 793                 fatal("Server returned different OID than expected");
 794
 795         packet_check_eom();
 796
 797         free(oidv);
 798
 799         if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
 800                 /* Start again with next method on list */
 801                 debug("Trying to start again");
 802                 userauth(authctxt, NULL);
 803                 return;
 804         }
 805 }
 806
 807 /* ARGSUSED */
 808 void
 809 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
 810 {
 811         Authctxt *authctxt = ctxt;
 812         gss_buffer_desc recv_tok;
 813         OM_uint32 status;
 814         u_int slen;
 815
 816         if (authctxt == NULL)
 817                 fatal("input_gssapi_response: no authentication context");
 818
 819         recv_tok.value = packet_get_string(&slen);
 820         recv_tok.length = slen; /* safe typecast */
 821
 822         packet_check_eom();
 823
 824         status = process_gssapi_token(ctxt, &recv_tok);
 825
 826         free(recv_tok.value);
 827
 828         if (GSS_ERROR(status)) {
 829                 /* Start again with the next method in the list */
 830                 userauth(authctxt, NULL);
 831                 return;
 832         }
 833 }
 834
 835 /* ARGSUSED */
 836 void
 837 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
 838 {
 839         Authctxt *authctxt = ctxt;
 840         Gssctxt *gssctxt;
 841         gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
 842         gss_buffer_desc recv_tok;
 843         OM_uint32 ms;
 844         u_int len;
 845
 846         if (authctxt == NULL)
 847                 fatal("input_gssapi_response: no authentication context");
 848         gssctxt = authctxt->methoddata;
 849
 850         recv_tok.value = packet_get_string(&len);
 851         recv_tok.length = len;
 852
 853         packet_check_eom();
 854
 855         /* Stick it into GSSAPI and see what it says */
 856         (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
 857             &recv_tok, &send_tok, NULL);
 858
 859         free(recv_tok.value);
 860         gss_release_buffer(&ms, &send_tok);
 861
 862         /* Server will be returning a failed packet after this one */
 863 }
 864
 865 /* ARGSUSED */
 866 void
 867 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
 868 {
 869         char *msg;
 870         char *lang;
 871
 872         /* maj */(void)packet_get_int();
 873         /* min */(void)packet_get_int();
 874         msg=packet_get_string(NULL);
 875         lang=packet_get_string(NULL);
 876
 877         packet_check_eom();
 878
 879         debug("Server GSSAPI Error:\n%s", msg);
 880         free(msg);
 881         free(lang);
 882 }
 883 #endif /* GSSAPI */
 884
 885 int
 886 userauth_none(Authctxt *authctxt)
 887 {
 888         /* initial userauth request */
 889         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 890         packet_put_cstring(authctxt->server_user);
 891         packet_put_cstring(authctxt->service);
 892         packet_put_cstring(authctxt->method->name);
 893         packet_send();
 894         return 1;
 895 }
 896
 897 int
 898 userauth_passwd(Authctxt *authctxt)
 899 {
 900         static int attempt = 0;
 901         char prompt[150];
 902         char *password;
 903         const char *host = options.host_key_alias ?  options.host_key_alias :
 904             authctxt->host;
 905
 906         if (attempt++ >= options.number_of_password_prompts)
 907                 return 0;
 908
 909         if (attempt != 1)
 910                 error("Permission denied, please try again.");
 911
 912         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
 913             authctxt->server_user, host);
 914         password = read_passphrase(prompt, 0);
 915         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 916         packet_put_cstring(authctxt->server_user);
 917         packet_put_cstring(authctxt->service);
 918         packet_put_cstring(authctxt->method->name);
 919         packet_put_char(0);
 920         packet_put_cstring(password);
 921         memset(password, 0, strlen(password));
 922         free(password);
 923         packet_add_padding(64);
 924         packet_send();
 925
 926         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
 927             &input_userauth_passwd_changereq);
 928
 929         return 1;
 930 }
 931
 932 /*
 933  * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
 934  */
 935 /* ARGSUSED */
 936 void
 937 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
 938 {
 939         Authctxt *authctxt = ctxt;
 940         char *info, *lang, *password = NULL, *retype = NULL;
 941         char prompt[150];
 942         const char *host = options.host_key_alias ? options.host_key_alias :
 943             authctxt->host;
 944
 945         debug2("input_userauth_passwd_changereq");
 946
 947         if (authctxt == NULL)
 948                 fatal("input_userauth_passwd_changereq: "
 949                     "no authentication context");
 950
 951         info = packet_get_string(NULL);
 952         lang = packet_get_string(NULL);
 953         if (strlen(info) > 0)
 954                 logit("%s", info);
 955         free(info);
 956         free(lang);
 957         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 958         packet_put_cstring(authctxt->server_user);
 959         packet_put_cstring(authctxt->service);
 960         packet_put_cstring(authctxt->method->name);
 961         packet_put_char(1);                     /* additional info */
 962         snprintf(prompt, sizeof(prompt),
 963             "Enter %.30s@%.128s's old password: ",
 964             authctxt->server_user, host);
 965         password = read_passphrase(prompt, 0);
 966         packet_put_cstring(password);
 967         memset(password, 0, strlen(password));
 968         free(password);
 969         password = NULL;
 970         while (password == NULL) {
 971                 snprintf(prompt, sizeof(prompt),
 972                     "Enter %.30s@%.128s's new password: ",
 973                     authctxt->server_user, host);
 974                 password = read_passphrase(prompt, RP_ALLOW_EOF);
 975                 if (password == NULL) {
 976                         /* bail out */
 977                         return;
 978                 }
 979                 snprintf(prompt, sizeof(prompt),
 980                     "Retype %.30s@%.128s's new password: ",
 981                     authctxt->server_user, host);
 982                 retype = read_passphrase(prompt, 0);
 983                 if (strcmp(password, retype) != 0) {
 984                         memset(password, 0, strlen(password));
 985                         free(password);
 986                         logit("Mismatch; try again, EOF to quit.");
 987                         password = NULL;
 988                 }
 989                 memset(retype, 0, strlen(retype));
 990                 free(retype);
 991         }
 992         packet_put_cstring(password);
 993         memset(password, 0, strlen(password));
 994         free(password);
 995         packet_add_padding(64);
 996         packet_send();
 997
 998         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
 999             &input_userauth_passwd_changereq);
1000 }
1001
1002 #ifdef JPAKE
1003 static char *
1004 pw_encrypt(const char *password, const char *crypt_scheme, const char *salt)
1005 {
1006         /* OpenBSD crypt(3) handles all of these */
1007         if (strcmp(crypt_scheme, "crypt") == 0 ||
1008             strcmp(crypt_scheme, "bcrypt") == 0 ||
1009             strcmp(crypt_scheme, "md5crypt") == 0 ||
1010             strcmp(crypt_scheme, "crypt-extended") == 0)
1011                 return xstrdup(crypt(password, salt));
1012         error("%s: unsupported password encryption scheme \"%.100s\"",
1013             __func__, crypt_scheme);
1014         return NULL;
1015 }
1016
1017 static BIGNUM *
1018 jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme,
1019     const char *salt)
1020 {
1021         char prompt[256], *password, *crypted;
1022         u_char *secret;
1023         u_int secret_len;
1024         BIGNUM *ret;
1025
1026         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ",
1027             authctxt->server_user, authctxt->host);
1028         password = read_passphrase(prompt, 0);
1029
1030         if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) {
1031                 logit("Disabling %s authentication", authctxt->method->name);
1032                 authctxt->method->enabled = NULL;
1033                 /* Continue with an empty password to fail gracefully */
1034                 crypted = xstrdup("");
1035         }
1036
1037 #ifdef JPAKE_DEBUG
1038         debug3("%s: salt = %s", __func__, salt);
1039         debug3("%s: scheme = %s", __func__, crypt_scheme);
1040         debug3("%s: crypted = %s", __func__, crypted);
1041 #endif
1042
1043         if (hash_buffer(crypted, strlen(crypted), SSH_DIGEST_SHA1,
1044             &secret, &secret_len) != 0)
1045                 fatal("%s: hash_buffer", __func__);
1046
1047         bzero(password, strlen(password));
1048         bzero(crypted, strlen(crypted));
1049         free(password);
1050         free(crypted);
1051
1052         if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL)
1053                 fatal("%s: BN_bin2bn (secret)", __func__);
1054         bzero(secret, secret_len);
1055         free(secret);
1056
1057         return ret;
1058 }
1059
1060 /* ARGSUSED */
1061 void
1062 input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt)
1063 {
1064         Authctxt *authctxt = ctxt;
1065         struct jpake_ctx *pctx = authctxt->methoddata;
1066         u_char *x3_proof, *x4_proof, *x2_s_proof;
1067         u_int x3_proof_len, x4_proof_len, x2_s_proof_len;
1068         char *crypt_scheme, *salt;
1069
1070         /* Disable this message */
1071         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL);
1072
1073         if ((pctx->g_x3 = BN_new()) == NULL ||
1074             (pctx->g_x4 = BN_new()) == NULL)
1075                 fatal("%s: BN_new", __func__);
1076
1077         /* Fetch step 1 values */
1078         crypt_scheme = packet_get_string(NULL);
1079         salt = packet_get_string(NULL);
1080         pctx->server_id = packet_get_string(&pctx->server_id_len);
1081         packet_get_bignum2(pctx->g_x3);
1082         packet_get_bignum2(pctx->g_x4);
1083         x3_proof = packet_get_string(&x3_proof_len);
1084         x4_proof = packet_get_string(&x4_proof_len);
1085         packet_check_eom();
1086
1087         JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__));
1088
1089         /* Obtain password and derive secret */
1090         pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt);
1091         bzero(crypt_scheme, strlen(crypt_scheme));
1092         bzero(salt, strlen(salt));
1093         free(crypt_scheme);
1094         free(salt);
1095         JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__));
1096
1097         /* Calculate step 2 values */
1098         jpake_step2(pctx->grp, pctx->s, pctx->g_x1,
1099             pctx->g_x3, pctx->g_x4, pctx->x2,
1100             pctx->server_id, pctx->server_id_len,
1101             pctx->client_id, pctx->client_id_len,
1102             x3_proof, x3_proof_len,
1103             x4_proof, x4_proof_len,
1104             &pctx->a,
1105             &x2_s_proof, &x2_s_proof_len);
1106
1107         bzero(x3_proof, x3_proof_len);
1108         bzero(x4_proof, x4_proof_len);
1109         free(x3_proof);
1110         free(x4_proof);
1111
1112         JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__));
1113
1114         /* Send values for step 2 */
1115         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2);
1116         packet_put_bignum2(pctx->a);
1117         packet_put_string(x2_s_proof, x2_s_proof_len);
1118         packet_send();
1119
1120         bzero(x2_s_proof, x2_s_proof_len);
1121         free(x2_s_proof);
1122
1123         /* Expect step 2 packet from peer */
1124         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2,
1125             input_userauth_jpake_server_step2);
1126 }
1127
1128 /* ARGSUSED */
1129 void
1130 input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt)
1131 {
1132         Authctxt *authctxt = ctxt;
1133         struct jpake_ctx *pctx = authctxt->methoddata;
1134         u_char *x4_s_proof;
1135         u_int x4_s_proof_len;
1136
1137         /* Disable this message */
1138         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL);
1139
1140         if ((pctx->b = BN_new()) == NULL)
1141                 fatal("%s: BN_new", __func__);
1142
1143         /* Fetch step 2 values */
1144         packet_get_bignum2(pctx->b);
1145         x4_s_proof = packet_get_string(&x4_s_proof_len);
1146         packet_check_eom();
1147
1148         JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__));
1149
1150         /* Derive shared key and calculate confirmation hash */
1151         jpake_key_confirm(pctx->grp, pctx->s, pctx->b,
1152             pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4,
1153             pctx->client_id, pctx->client_id_len,
1154             pctx->server_id, pctx->server_id_len,
1155             session_id2, session_id2_len,
1156             x4_s_proof, x4_s_proof_len,
1157             &pctx->k,
1158             &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len);
1159
1160         bzero(x4_s_proof, x4_s_proof_len);
1161         free(x4_s_proof);
1162
1163         JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__));
1164
1165         /* Send key confirmation proof */
1166         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM);
1167         packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len);
1168         packet_send();
1169
1170         /* Expect confirmation from peer */
1171         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM,
1172             input_userauth_jpake_server_confirm);
1173 }
1174
1175 /* ARGSUSED */
1176 void
1177 input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt)
1178 {
1179         Authctxt *authctxt = ctxt;
1180         struct jpake_ctx *pctx = authctxt->methoddata;
1181
1182         /* Disable this message */
1183         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL);
1184
1185         pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len);
1186         packet_check_eom();
1187
1188         JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__));
1189
1190         /* Verify expected confirmation hash */
1191         if (jpake_check_confirm(pctx->k,
1192             pctx->server_id, pctx->server_id_len,
1193             session_id2, session_id2_len,
1194             pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1)
1195                 debug("%s: %s success", __func__, authctxt->method->name);
1196         else {
1197                 debug("%s: confirmation mismatch", __func__);
1198                 /* XXX stash this so if auth succeeds then we can warn/kill */
1199         }
1200
1201         userauth_jpake_cleanup(authctxt);
1202 }
1203 #endif /* JPAKE */
1204
1205 static int
1206 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
1207     u_char *data, u_int datalen)
1208 {
1209         Key *prv;
1210         int ret;
1211
1212         /* the agent supports this key */
1213         if (id->ac)
1214                 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
1215                     data, datalen));
1216         /*
1217          * we have already loaded the private key or
1218          * the private key is stored in external hardware
1219          */
1220         if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
1221                 return (key_sign(id->key, sigp, lenp, data, datalen));
1222         /* load the private key from the file */
1223         if ((prv = load_identity_file(id->filename, id->userprovided)) == NULL)
1224                 return (-1);
1225         ret = key_sign(prv, sigp, lenp, data, datalen);
1226         key_free(prv);
1227         return (ret);
1228 }
1229
1230 static int
1231 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
1232 {
1233         Buffer b;
1234         u_char *blob, *signature;
1235         u_int bloblen, slen;
1236         u_int skip = 0;
1237         int ret = -1;
1238         int have_sig = 1;
1239         char *fp;
1240
1241         fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
1242         debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp);
1243         free(fp);
1244
1245         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1246                 /* we cannot handle this key */
1247                 debug3("sign_and_send_pubkey: cannot handle key");
1248                 return 0;
1249         }
1250         /* data to be signed */
1251         buffer_init(&b);
1252         if (datafellows & SSH_OLD_SESSIONID) {
1253                 buffer_append(&b, session_id2, session_id2_len);
1254                 skip = session_id2_len;
1255         } else {
1256                 buffer_put_string(&b, session_id2, session_id2_len);
1257                 skip = buffer_len(&b);
1258         }
1259         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1260         buffer_put_cstring(&b, authctxt->server_user);
1261         buffer_put_cstring(&b,
1262             datafellows & SSH_BUG_PKSERVICE ?
1263             "ssh-userauth" :
1264             authctxt->service);
1265         if (datafellows & SSH_BUG_PKAUTH) {
1266                 buffer_put_char(&b, have_sig);
1267         } else {
1268                 buffer_put_cstring(&b, authctxt->method->name);
1269                 buffer_put_char(&b, have_sig);
1270                 buffer_put_cstring(&b, key_ssh_name(id->key));
1271         }
1272         buffer_put_string(&b, blob, bloblen);
1273
1274         /* generate signature */
1275         ret = identity_sign(id, &signature, &slen,
1276             buffer_ptr(&b), buffer_len(&b));
1277         if (ret == -1) {
1278                 free(blob);
1279                 buffer_free(&b);
1280                 return 0;
1281         }
1282 #ifdef DEBUG_PK
1283         buffer_dump(&b);
1284 #endif
1285         if (datafellows & SSH_BUG_PKSERVICE) {
1286                 buffer_clear(&b);
1287                 buffer_append(&b, session_id2, session_id2_len);
1288                 skip = session_id2_len;
1289                 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1290                 buffer_put_cstring(&b, authctxt->server_user);
1291                 buffer_put_cstring(&b, authctxt->service);
1292                 buffer_put_cstring(&b, authctxt->method->name);
1293                 buffer_put_char(&b, have_sig);
1294                 if (!(datafellows & SSH_BUG_PKAUTH))
1295                         buffer_put_cstring(&b, key_ssh_name(id->key));
1296                 buffer_put_string(&b, blob, bloblen);
1297         }
1298         free(blob);
1299
1300         /* append signature */
1301         buffer_put_string(&b, signature, slen);
1302         free(signature);
1303
1304         /* skip session id and packet type */
1305         if (buffer_len(&b) < skip + 1)
1306                 fatal("userauth_pubkey: internal error");
1307         buffer_consume(&b, skip + 1);
1308
1309         /* put remaining data from buffer into packet */
1310         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1311         packet_put_raw(buffer_ptr(&b), buffer_len(&b));
1312         buffer_free(&b);
1313         packet_send();
1314
1315         return 1;
1316 }
1317
1318 static int
1319 send_pubkey_test(Authctxt *authctxt, Identity *id)
1320 {
1321         u_char *blob;
1322         u_int bloblen, have_sig = 0;
1323
1324         debug3("send_pubkey_test");
1325
1326         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1327                 /* we cannot handle this key */
1328                 debug3("send_pubkey_test: cannot handle key");
1329                 return 0;
1330         }
1331         /* register callback for USERAUTH_PK_OK message */
1332         dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
1333
1334         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1335         packet_put_cstring(authctxt->server_user);
1336         packet_put_cstring(authctxt->service);
1337         packet_put_cstring(authctxt->method->name);
1338         packet_put_char(have_sig);
1339         if (!(datafellows & SSH_BUG_PKAUTH))
1340                 packet_put_cstring(key_ssh_name(id->key));
1341         packet_put_string(blob, bloblen);
1342         free(blob);
1343         packet_send();
1344         return 1;
1345 }
1346
1347 static Key *
1348 load_identity_file(char *filename, int userprovided)
1349 {
1350         Key *private;
1351         char prompt[300], *passphrase;
1352         int perm_ok = 0, quit, i;
1353         struct stat st;
1354
1355         if (stat(filename, &st) < 0) {
1356                 (userprovided ? logit : debug3)("no such identity: %s: %s",
1357                     filename, strerror(errno));
1358                 return NULL;
1359         }
1360         private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
1361         if (!perm_ok) {
1362                 if (private != NULL)
1363                         key_free(private);
1364                 return NULL;
1365         }
1366         if (private == NULL) {
1367                 if (options.batch_mode)
1368                         return NULL;
1369                 snprintf(prompt, sizeof prompt,
1370                     "Enter passphrase for key '%.100s': ", filename);
1371                 for (i = 0; i < options.number_of_password_prompts; i++) {
1372                         passphrase = read_passphrase(prompt, 0);
1373                         if (strcmp(passphrase, "") != 0) {
1374                                 private = key_load_private_type(KEY_UNSPEC,
1375                                     filename, passphrase, NULL, NULL);
1376                                 quit = 0;
1377                         } else {
1378                                 debug2("no passphrase given, try next key");
1379                                 quit = 1;
1380                         }
1381                         memset(passphrase, 0, strlen(passphrase));
1382                         free(passphrase);
1383                         if (private != NULL || quit)
1384                                 break;
1385                         debug2("bad passphrase given, try again...");
1386                 }
1387         }
1388         return private;
1389 }
1390
1391 /*
1392  * try keys in the following order:
1393  *      1. agent keys that are found in the config file
1394  *      2. other agent keys
1395  *      3. keys that are only listed in the config file
1396  */
1397 static void
1398 pubkey_prepare(Authctxt *authctxt)
1399 {
1400         Identity *id, *id2, *tmp;
1401         Idlist agent, files, *preferred;
1402         Key *key;
1403         AuthenticationConnection *ac;
1404         char *comment;
1405         int i, found;
1406
1407         TAILQ_INIT(&agent);     /* keys from the agent */
1408         TAILQ_INIT(&files);     /* keys from the config file */
1409         preferred = &authctxt->keys;
1410         TAILQ_INIT(preferred);  /* preferred order of keys */
1411
1412         /* list of keys stored in the filesystem and PKCS#11 */
1413         for (i = 0; i < options.num_identity_files; i++) {
1414                 key = options.identity_keys[i];
1415                 if (key && key->type == KEY_RSA1)
1416                         continue;
1417                 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER)
1418                         continue;
1419                 options.identity_keys[i] = NULL;
1420                 id = xcalloc(1, sizeof(*id));
1421                 id->key = key;
1422                 id->filename = xstrdup(options.identity_files[i]);
1423                 id->userprovided = options.identity_file_userprovided[i];
1424                 TAILQ_INSERT_TAIL(&files, id, next);
1425         }
1426         /* Prefer PKCS11 keys that are explicitly listed */
1427         TAILQ_FOREACH_SAFE(id, &files, next, tmp) {
1428                 if (id->key == NULL || (id->key->flags & KEY_FLAG_EXT) == 0)
1429                         continue;
1430                 found = 0;
1431                 TAILQ_FOREACH(id2, &files, next) {
1432                         if (id2->key == NULL ||
1433                             (id2->key->flags & KEY_FLAG_EXT) != 0)
1434                                 continue;
1435                         if (key_equal(id->key, id2->key)) {
1436                                 TAILQ_REMOVE(&files, id, next);
1437                                 TAILQ_INSERT_TAIL(preferred, id, next);
1438                                 found = 1;
1439                                 break;
1440                         }
1441                 }
1442                 /* If IdentitiesOnly set and key not found then don't use it */
1443                 if (!found && options.identities_only) {
1444                         TAILQ_REMOVE(&files, id, next);
1445                         bzero(id, sizeof(*id));
1446                         free(id);
1447                 }
1448         }
1449         /* list of keys supported by the agent */
1450         if ((ac = ssh_get_authentication_connection())) {
1451                 for (key = ssh_get_first_identity(ac, &comment, 2);
1452                     key != NULL;
1453                     key = ssh_get_next_identity(ac, &comment, 2)) {
1454                         found = 0;
1455                         TAILQ_FOREACH(id, &files, next) {
1456                                 /* agent keys from the config file are preferred */
1457                                 if (key_equal(key, id->key)) {
1458                                         key_free(key);
1459                                         free(comment);
1460                                         TAILQ_REMOVE(&files, id, next);
1461                                         TAILQ_INSERT_TAIL(preferred, id, next);
1462                                         id->ac = ac;
1463                                         found = 1;
1464                                         break;
1465                                 }
1466                         }
1467                         if (!found && !options.identities_only) {
1468                                 id = xcalloc(1, sizeof(*id));
1469                                 id->key = key;
1470                                 id->filename = comment;
1471                                 id->ac = ac;
1472                                 TAILQ_INSERT_TAIL(&agent, id, next);
1473                         }
1474                 }
1475                 /* append remaining agent keys */
1476                 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1477                         TAILQ_REMOVE(&agent, id, next);
1478                         TAILQ_INSERT_TAIL(preferred, id, next);
1479                 }
1480                 authctxt->agent = ac;
1481         }
1482         /* append remaining keys from the config file */
1483         for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1484                 TAILQ_REMOVE(&files, id, next);
1485                 TAILQ_INSERT_TAIL(preferred, id, next);
1486         }
1487         TAILQ_FOREACH(id, preferred, next) {
1488                 debug2("key: %s (%p),%s", id->filename, id->key,
1489                     id->userprovided ? " explicit" : "");
1490         }
1491 }
1492
1493 static void
1494 pubkey_cleanup(Authctxt *authctxt)
1495 {
1496         Identity *id;
1497
1498         if (authctxt->agent != NULL)
1499                 ssh_close_authentication_connection(authctxt->agent);
1500         for (id = TAILQ_FIRST(&authctxt->keys); id;
1501             id = TAILQ_FIRST(&authctxt->keys)) {
1502                 TAILQ_REMOVE(&authctxt->keys, id, next);
1503                 if (id->key)
1504                         key_free(id->key);
1505                 free(id->filename);
1506                 free(id);
1507         }
1508 }
1509
1510 int
1511 userauth_pubkey(Authctxt *authctxt)
1512 {
1513         Identity *id;
1514         int sent = 0;
1515
1516         while ((id = TAILQ_FIRST(&authctxt->keys))) {
1517                 if (id->tried++)
1518                         return (0);
1519                 /* move key to the end of the queue */
1520                 TAILQ_REMOVE(&authctxt->keys, id, next);
1521                 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1522                 /*
1523                  * send a test message if we have the public key. for
1524                  * encrypted keys we cannot do this and have to load the
1525                  * private key instead
1526                  */
1527                 if (id->key != NULL) {
1528                         if (key_type_plain(id->key->type) == KEY_RSA &&
1529                             (datafellows & SSH_BUG_RSASIGMD5) != 0) {
1530                                 debug("Skipped %s key %s for RSA/MD5 server",
1531                                     key_type(id->key), id->filename);
1532                         } else if (id->key->type != KEY_RSA1) {
1533                                 debug("Offering %s public key: %s",
1534                                     key_type(id->key), id->filename);
1535                                 sent = send_pubkey_test(authctxt, id);
1536                         }
1537                 } else {
1538                         debug("Trying private key: %s", id->filename);
1539                         id->key = load_identity_file(id->filename,
1540                             id->userprovided);
1541                         if (id->key != NULL) {
1542                                 id->isprivate = 1;
1543                                 if (key_type_plain(id->key->type) == KEY_RSA &&
1544                                     (datafellows & SSH_BUG_RSASIGMD5) != 0) {
1545                                         debug("Skipped %s key %s for RSA/MD5 "
1546                                             "server", key_type(id->key),
1547                                             id->filename);
1548                                 } else {
1549                                         sent = sign_and_send_pubkey(
1550                                             authctxt, id);
1551                                 }
1552                                 key_free(id->key);
1553                                 id->key = NULL;
1554                         }
1555                 }
1556                 if (sent)
1557                         return (sent);
1558         }
1559         return (0);
1560 }
1561
1562 /*
1563  * Send userauth request message specifying keyboard-interactive method.
1564  */
1565 int
1566 userauth_kbdint(Authctxt *authctxt)
1567 {
1568         static int attempt = 0;
1569
1570         if (attempt++ >= options.number_of_password_prompts)
1571                 return 0;
1572         /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1573         if (attempt > 1 && !authctxt->info_req_seen) {
1574                 debug3("userauth_kbdint: disable: no info_req_seen");
1575                 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1576                 return 0;
1577         }
1578
1579         debug2("userauth_kbdint");
1580         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1581         packet_put_cstring(authctxt->server_user);
1582         packet_put_cstring(authctxt->service);
1583         packet_put_cstring(authctxt->method->name);
1584         packet_put_cstring("");                                 /* lang */
1585         packet_put_cstring(options.kbd_interactive_devices ?
1586             options.kbd_interactive_devices : "");
1587         packet_send();
1588
1589         dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1590         return 1;
1591 }
1592
1593 /*
1594  * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1595  */
1596 void
1597 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1598 {
1599         Authctxt *authctxt = ctxt;
1600         char *name, *inst, *lang, *prompt, *response;
1601         u_int num_prompts, i;
1602         int echo = 0;
1603
1604         debug2("input_userauth_info_req");
1605
1606         if (authctxt == NULL)
1607                 fatal("input_userauth_info_req: no authentication context");
1608
1609         authctxt->info_req_seen = 1;
1610
1611         name = packet_get_string(NULL);
1612         inst = packet_get_string(NULL);
1613         lang = packet_get_string(NULL);
1614         if (strlen(name) > 0)
1615                 logit("%s", name);
1616         if (strlen(inst) > 0)
1617                 logit("%s", inst);
1618         free(name);
1619         free(inst);
1620         free(lang);
1621
1622         num_prompts = packet_get_int();
1623         /*
1624          * Begin to build info response packet based on prompts requested.
1625          * We commit to providing the correct number of responses, so if
1626          * further on we run into a problem that prevents this, we have to
1627          * be sure and clean this up and send a correct error response.
1628          */
1629         packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1630         packet_put_int(num_prompts);
1631
1632         debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1633         for (i = 0; i < num_prompts; i++) {
1634                 prompt = packet_get_string(NULL);
1635                 echo = packet_get_char();
1636
1637                 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1638
1639                 packet_put_cstring(response);
1640                 memset(response, 0, strlen(response));
1641                 free(response);
1642                 free(prompt);
1643         }
1644         packet_check_eom(); /* done with parsing incoming message. */
1645
1646         packet_add_padding(64);
1647         packet_send();
1648 }
1649
1650 static int
1651 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1652     u_char *data, u_int datalen)
1653 {
1654         Buffer b;
1655         struct stat st;
1656         pid_t pid;
1657         int to[2], from[2], status, version = 2;
1658
1659         debug2("ssh_keysign called");
1660
1661         if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1662                 error("ssh_keysign: not installed: %s", strerror(errno));
1663                 return -1;
1664         }
1665         if (fflush(stdout) != 0)
1666                 error("ssh_keysign: fflush: %s", strerror(errno));
1667         if (pipe(to) < 0) {
1668                 error("ssh_keysign: pipe: %s", strerror(errno));
1669                 return -1;
1670         }
1671         if (pipe(from) < 0) {
1672                 error("ssh_keysign: pipe: %s", strerror(errno));
1673                 return -1;
1674         }
1675         if ((pid = fork()) < 0) {
1676                 error("ssh_keysign: fork: %s", strerror(errno));
1677                 return -1;
1678         }
1679         if (pid == 0) {
1680                 /* keep the socket on exec */
1681                 fcntl(packet_get_connection_in(), F_SETFD, 0);
1682                 permanently_drop_suid(getuid());
1683                 close(from[0]);
1684                 if (dup2(from[1], STDOUT_FILENO) < 0)
1685                         fatal("ssh_keysign: dup2: %s", strerror(errno));
1686                 close(to[1]);
1687                 if (dup2(to[0], STDIN_FILENO) < 0)
1688                         fatal("ssh_keysign: dup2: %s", strerror(errno));
1689                 close(from[1]);
1690                 close(to[0]);
1691                 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1692                 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1693                     strerror(errno));
1694         }
1695         close(from[1]);
1696         close(to[0]);
1697
1698         buffer_init(&b);
1699         buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1700         buffer_put_string(&b, data, datalen);
1701         if (ssh_msg_send(to[1], version, &b) == -1)
1702                 fatal("ssh_keysign: couldn't send request");
1703
1704         if (ssh_msg_recv(from[0], &b) < 0) {
1705                 error("ssh_keysign: no reply");
1706                 buffer_free(&b);
1707                 return -1;
1708         }
1709         close(from[0]);
1710         close(to[1]);
1711
1712         while (waitpid(pid, &status, 0) < 0)
1713                 if (errno != EINTR)
1714                         break;
1715
1716         if (buffer_get_char(&b) != version) {
1717                 error("ssh_keysign: bad version");
1718                 buffer_free(&b);
1719                 return -1;
1720         }
1721         *sigp = buffer_get_string(&b, lenp);
1722         buffer_free(&b);
1723
1724         return 0;
1725 }
1726
1727 int
1728 userauth_hostbased(Authctxt *authctxt)
1729 {
1730         Key *private = NULL;
1731         Sensitive *sensitive = authctxt->sensitive;
1732         Buffer b;
1733         u_char *signature, *blob;
1734         char *chost, *pkalg, *p;
1735         const char *service;
1736         u_int blen, slen;
1737         int ok, i, found = 0;
1738
1739         /* check for a useful key */
1740         for (i = 0; i < sensitive->nkeys; i++) {
1741                 private = sensitive->keys[i];
1742                 if (private && private->type != KEY_RSA1) {
1743                         found = 1;
1744                         /* we take and free the key */
1745                         sensitive->keys[i] = NULL;
1746                         break;
1747                 }
1748         }
1749         if (!found) {
1750                 debug("No more client hostkeys for hostbased authentication.");
1751                 return 0;
1752         }
1753         if (key_to_blob(private, &blob, &blen) == 0) {
1754                 key_free(private);
1755                 return 0;
1756         }
1757         /* figure out a name for the client host */
1758         p = get_local_name(packet_get_connection_in());
1759         if (p == NULL) {
1760                 error("userauth_hostbased: cannot get local ipaddr/name");
1761                 key_free(private);
1762                 free(blob);
1763                 return 0;
1764         }
1765         xasprintf(&chost, "%s.", p);
1766         debug2("userauth_hostbased: chost %s", chost);
1767         free(p);
1768
1769         service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1770             authctxt->service;
1771         pkalg = xstrdup(key_ssh_name(private));
1772         buffer_init(&b);
1773         /* construct data */
1774         buffer_put_string(&b, session_id2, session_id2_len);
1775         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1776         buffer_put_cstring(&b, authctxt->server_user);
1777         buffer_put_cstring(&b, service);
1778         buffer_put_cstring(&b, authctxt->method->name);
1779         buffer_put_cstring(&b, pkalg);
1780         buffer_put_string(&b, blob, blen);
1781         buffer_put_cstring(&b, chost);
1782         buffer_put_cstring(&b, authctxt->local_user);
1783 #ifdef DEBUG_PK
1784         buffer_dump(&b);
1785 #endif
1786         if (sensitive->external_keysign)
1787                 ok = ssh_keysign(private, &signature, &slen,
1788                     buffer_ptr(&b), buffer_len(&b));
1789         else
1790                 ok = key_sign(private, &signature, &slen,
1791                     buffer_ptr(&b), buffer_len(&b));
1792         key_free(private);
1793         buffer_free(&b);
1794         if (ok != 0) {
1795                 error("key_sign failed");
1796                 free(chost);
1797                 free(pkalg);
1798                 free(blob);
1799                 return 0;
1800         }
1801         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1802         packet_put_cstring(authctxt->server_user);
1803         packet_put_cstring(authctxt->service);
1804         packet_put_cstring(authctxt->method->name);
1805         packet_put_cstring(pkalg);
1806         packet_put_string(blob, blen);
1807         packet_put_cstring(chost);
1808         packet_put_cstring(authctxt->local_user);
1809         packet_put_string(signature, slen);
1810         memset(signature, 's', slen);
1811         free(signature);
1812         free(chost);
1813         free(pkalg);
1814         free(blob);
1815
1816         packet_send();
1817         return 1;
1818 }
1819
1820 #ifdef JPAKE
1821 int
1822 userauth_jpake(Authctxt *authctxt)
1823 {
1824         struct jpake_ctx *pctx;
1825         u_char *x1_proof, *x2_proof;
1826         u_int x1_proof_len, x2_proof_len;
1827         static int attempt = 0; /* XXX share with userauth_password's? */
1828
1829         if (attempt++ >= options.number_of_password_prompts)
1830                 return 0;
1831         if (attempt != 1)
1832                 error("Permission denied, please try again.");
1833
1834         if (authctxt->methoddata != NULL)
1835                 fatal("%s: authctxt->methoddata already set (%p)",
1836                     __func__, authctxt->methoddata);
1837
1838         authctxt->methoddata = pctx = jpake_new();
1839
1840         /*
1841          * Send request immediately, to get the protocol going while
1842          * we do the initial computations.
1843          */
1844         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1845         packet_put_cstring(authctxt->server_user);
1846         packet_put_cstring(authctxt->service);
1847         packet_put_cstring(authctxt->method->name);
1848         packet_send();
1849         packet_write_wait();
1850
1851         jpake_step1(pctx->grp,
1852             &pctx->client_id, &pctx->client_id_len,
1853             &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2,
1854             &x1_proof, &x1_proof_len,
1855             &x2_proof, &x2_proof_len);
1856
1857         JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__));
1858
1859         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1);
1860         packet_put_string(pctx->client_id, pctx->client_id_len);
1861         packet_put_bignum2(pctx->g_x1);
1862         packet_put_bignum2(pctx->g_x2);
1863         packet_put_string(x1_proof, x1_proof_len);
1864         packet_put_string(x2_proof, x2_proof_len);
1865         packet_send();
1866
1867         bzero(x1_proof, x1_proof_len);
1868         bzero(x2_proof, x2_proof_len);
1869         free(x1_proof);
1870         free(x2_proof);
1871
1872         /* Expect step 1 packet from peer */
1873         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1,
1874             input_userauth_jpake_server_step1);
1875         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS,
1876             &input_userauth_success_unexpected);
1877
1878         return 1;
1879 }
1880
1881 void
1882 userauth_jpake_cleanup(Authctxt *authctxt)
1883 {
1884         debug3("%s: clean up", __func__);
1885         if (authctxt->methoddata != NULL) {
1886                 jpake_free(authctxt->methoddata);
1887                 authctxt->methoddata = NULL;
1888         }
1889         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
1890 }
1891 #endif /* JPAKE */
1892
1893 /* find auth method */
1894
1895 /*
1896  * given auth method name, if configurable options permit this method fill
1897  * in auth_ident field and return true, otherwise return false.
1898  */
1899 static int
1900 authmethod_is_enabled(Authmethod *method)
1901 {
1902         if (method == NULL)
1903                 return 0;
1904         /* return false if options indicate this method is disabled */
1905         if  (method->enabled == NULL || *method->enabled == 0)
1906                 return 0;
1907         /* return false if batch mode is enabled but method needs interactive mode */
1908         if  (method->batch_flag != NULL && *method->batch_flag != 0)
1909                 return 0;
1910         return 1;
1911 }
1912
1913 static Authmethod *
1914 authmethod_lookup(const char *name)
1915 {
1916         Authmethod *method = NULL;
1917         if (name != NULL)
1918                 for (method = authmethods; method->name != NULL; method++)
1919                         if (strcmp(name, method->name) == 0)
1920                                 return method;
1921         debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1922         return NULL;
1923 }
1924
1925 /* XXX internal state */
1926 static Authmethod *current = NULL;
1927 static char *supported = NULL;
1928 static char *preferred = NULL;
1929
1930 /*
1931  * Given the authentication method list sent by the server, return the
1932  * next method we should try.  If the server initially sends a nil list,
1933  * use a built-in default list.
1934  */
1935 static Authmethod *
1936 authmethod_get(char *authlist)
1937 {
1938         char *name = NULL;
1939         u_int next;
1940
1941         /* Use a suitable default if we're passed a nil list.  */
1942         if (authlist == NULL || strlen(authlist) == 0)
1943                 authlist = options.preferred_authentications;
1944
1945         if (supported == NULL || strcmp(authlist, supported) != 0) {
1946                 debug3("start over, passed a different list %s", authlist);
1947                 free(supported);
1948                 supported = xstrdup(authlist);
1949                 preferred = options.preferred_authentications;
1950                 debug3("preferred %s", preferred);
1951                 current = NULL;
1952         } else if (current != NULL && authmethod_is_enabled(current))
1953                 return current;
1954
1955         for (;;) {
1956                 if ((name = match_list(preferred, supported, &next)) == NULL) {
1957                         debug("No more authentication methods to try.");
1958                         current = NULL;
1959                         return NULL;
1960                 }
1961                 preferred += next;
1962                 debug3("authmethod_lookup %s", name);
1963                 debug3("remaining preferred: %s", preferred);
1964                 if ((current = authmethod_lookup(name)) != NULL &&
1965                     authmethod_is_enabled(current)) {
1966                         debug3("authmethod_is_enabled %s", name);
1967                         debug("Next authentication method: %s", name);
1968                         free(name);
1969                         return current;
1970                 }
1971                 free(name);
1972         }
1973 }
1974
1975 static char *
1976 authmethods_get(void)
1977 {
1978         Authmethod *method = NULL;
1979         Buffer b;
1980         char *list;
1981
1982         buffer_init(&b);
1983         for (method = authmethods; method->name != NULL; method++) {
1984                 if (authmethod_is_enabled(method)) {
1985                         if (buffer_len(&b) > 0)
1986                                 buffer_append(&b, ",", 1);
1987                         buffer_append(&b, method->name, strlen(method->name));
1988                 }
1989         }
1990         buffer_append(&b, "\0", 1);
1991         list = xstrdup(buffer_ptr(&b));
1992         buffer_free(&b);
1993         return list;
1994 }
1995