crypto/openssh/sshconnect2.c

   1 /* $OpenBSD: sshconnect2.c,v 1.170 2008/11/04 08:22:13 djm Exp $ */
   2 /*
   3  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   4  * Copyright (c) 2008 Damien Miller.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "includes.h"
  28
  29 #include <sys/types.h>
  30 #include <sys/socket.h>
  31 #include <sys/wait.h>
  32 #include <sys/stat.h>
  33
  34 #include <errno.h>
  35 #include <netdb.h>
  36 #include <pwd.h>
  37 #include <signal.h>
  38 #include <stdarg.h>
  39 #include <stdio.h>
  40 #include <string.h>
  41 #include <unistd.h>
  42 #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H)
  43 #include <vis.h>
  44 #endif
  45
  46 #include "openbsd-compat/sys-queue.h"
  47
  48 #include "xmalloc.h"
  49 #include "ssh.h"
  50 #include "ssh2.h"
  51 #include "buffer.h"
  52 #include "packet.h"
  53 #include "compat.h"
  54 #include "cipher.h"
  55 #include "key.h"
  56 #include "kex.h"
  57 #include "myproposal.h"
  58 #include "sshconnect.h"
  59 #include "authfile.h"
  60 #include "dh.h"
  61 #include "authfd.h"
  62 #include "log.h"
  63 #include "readconf.h"
  64 #include "misc.h"
  65 #include "match.h"
  66 #include "dispatch.h"
  67 #include "canohost.h"
  68 #include "msg.h"
  69 #include "pathnames.h"
  70 #include "uidswap.h"
  71 #include "jpake.h"
  72
  73 #ifdef GSSAPI
  74 #include "ssh-gss.h"
  75 #endif
  76
  77 /* import */
  78 extern char *client_version_string;
  79 extern char *server_version_string;
  80 extern Options options;
  81
  82 /*
  83  * SSH2 key exchange
  84  */
  85
  86 u_char *session_id2 = NULL;
  87 u_int session_id2_len = 0;
  88
  89 char *xxx_host;
  90 struct sockaddr *xxx_hostaddr;
  91
  92 Kex *xxx_kex = NULL;
  93
  94 static int
  95 verify_host_key_callback(Key *hostkey)
  96 {
  97         if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
  98                 fatal("Host key verification failed.");
  99         return 0;
 100 }
 101
 102 void
 103 ssh_kex2(char *host, struct sockaddr *hostaddr)
 104 {
 105         Kex *kex;
 106
 107         xxx_host = host;
 108         xxx_hostaddr = hostaddr;
 109
 110         if (options.ciphers == (char *)-1) {
 111                 logit("No valid ciphers for protocol version 2 given, using defaults.");
 112                 options.ciphers = NULL;
 113         }
 114         if (options.ciphers != NULL) {
 115                 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 116                 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
 117         }
 118         myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 119             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
 120         myproposal[PROPOSAL_ENC_ALGS_STOC] =
 121             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
 122         if (options.compression) {
 123                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 124                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
 125         } else {
 126                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 127                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
 128         }
 129         if (options.macs != NULL) {
 130                 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
 131                 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
 132         }
 133         if (options.hostkeyalgorithms != NULL)
 134                 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
 135                     options.hostkeyalgorithms;
 136
 137         if (options.rekey_limit)
 138                 packet_set_rekey_limit((u_int32_t)options.rekey_limit);
 139
 140         /* start key exchange */
 141         kex = kex_setup(myproposal);
 142         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
 143         kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
 144         kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
 145         kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
 146         kex->client_version_string=client_version_string;
 147         kex->server_version_string=server_version_string;
 148         kex->verify_host_key=&verify_host_key_callback;
 149
 150         xxx_kex = kex;
 151
 152         dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
 153
 154         session_id2 = kex->session_id;
 155         session_id2_len = kex->session_id_len;
 156
 157 #ifdef DEBUG_KEXDH
 158         /* send 1st encrypted/maced/compressed message */
 159         packet_start(SSH2_MSG_IGNORE);
 160         packet_put_cstring("markus");
 161         packet_send();
 162         packet_write_wait();
 163 #endif
 164 }
 165
 166 /*
 167  * Authenticate user
 168  */
 169
 170 typedef struct Authctxt Authctxt;
 171 typedef struct Authmethod Authmethod;
 172 typedef struct identity Identity;
 173 typedef struct idlist Idlist;
 174
 175 struct identity {
 176         TAILQ_ENTRY(identity) next;
 177         AuthenticationConnection *ac;   /* set if agent supports key */
 178         Key     *key;                   /* public/private key */
 179         char    *filename;              /* comment for agent-only keys */
 180         int     tried;
 181         int     isprivate;              /* key points to the private key */
 182 };
 183 TAILQ_HEAD(idlist, identity);
 184
 185 struct Authctxt {
 186         const char *server_user;
 187         const char *local_user;
 188         const char *host;
 189         const char *service;
 190         Authmethod *method;
 191         int success;
 192         char *authlist;
 193         /* pubkey */
 194         Idlist keys;
 195         AuthenticationConnection *agent;
 196         /* hostbased */
 197         Sensitive *sensitive;
 198         /* kbd-interactive */
 199         int info_req_seen;
 200         /* generic */
 201         void *methoddata;
 202 };
 203 struct Authmethod {
 204         char    *name;          /* string to compare against server's list */
 205         int     (*userauth)(Authctxt *authctxt);
 206         void    (*cleanup)(Authctxt *authctxt);
 207         int     *enabled;       /* flag in option struct that enables method */
 208         int     *batch_flag;    /* flag in option struct that disables method */
 209 };
 210
 211 void    input_userauth_success(int, u_int32_t, void *);
 212 void    input_userauth_failure(int, u_int32_t, void *);
 213 void    input_userauth_banner(int, u_int32_t, void *);
 214 void    input_userauth_error(int, u_int32_t, void *);
 215 void    input_userauth_info_req(int, u_int32_t, void *);
 216 void    input_userauth_pk_ok(int, u_int32_t, void *);
 217 void    input_userauth_passwd_changereq(int, u_int32_t, void *);
 218 void    input_userauth_jpake_server_step1(int, u_int32_t, void *);
 219 void    input_userauth_jpake_server_step2(int, u_int32_t, void *);
 220 void    input_userauth_jpake_server_confirm(int, u_int32_t, void *);
 221
 222 int     userauth_none(Authctxt *);
 223 int     userauth_pubkey(Authctxt *);
 224 int     userauth_passwd(Authctxt *);
 225 int     userauth_kbdint(Authctxt *);
 226 int     userauth_hostbased(Authctxt *);
 227 int     userauth_jpake(Authctxt *);
 228
 229 void    userauth_jpake_cleanup(Authctxt *);
 230
 231 #ifdef GSSAPI
 232 int     userauth_gssapi(Authctxt *authctxt);
 233 void    input_gssapi_response(int type, u_int32_t, void *);
 234 void    input_gssapi_token(int type, u_int32_t, void *);
 235 void    input_gssapi_hash(int type, u_int32_t, void *);
 236 void    input_gssapi_error(int, u_int32_t, void *);
 237 void    input_gssapi_errtok(int, u_int32_t, void *);
 238 #endif
 239
 240 void    userauth(Authctxt *, char *);
 241
 242 static int sign_and_send_pubkey(Authctxt *, Identity *);
 243 static void pubkey_prepare(Authctxt *);
 244 static void pubkey_cleanup(Authctxt *);
 245 static Key *load_identity_file(char *);
 246
 247 static Authmethod *authmethod_get(char *authlist);
 248 static Authmethod *authmethod_lookup(const char *name);
 249 static char *authmethods_get(void);
 250
 251 Authmethod authmethods[] = {
 252 #ifdef GSSAPI
 253         {"gssapi-with-mic",
 254                 userauth_gssapi,
 255                 NULL,
 256                 &options.gss_authentication,
 257                 NULL},
 258 #endif
 259         {"hostbased",
 260                 userauth_hostbased,
 261                 NULL,
 262                 &options.hostbased_authentication,
 263                 NULL},
 264         {"publickey",
 265                 userauth_pubkey,
 266                 NULL,
 267                 &options.pubkey_authentication,
 268                 NULL},
 269 #ifdef JPAKE
 270         {"jpake-01@openssh.com",
 271                 userauth_jpake,
 272                 userauth_jpake_cleanup,
 273                 &options.zero_knowledge_password_authentication,
 274                 &options.batch_mode},
 275 #endif
 276         {"keyboard-interactive",
 277                 userauth_kbdint,
 278                 NULL,
 279                 &options.kbd_interactive_authentication,
 280                 &options.batch_mode},
 281         {"password",
 282                 userauth_passwd,
 283                 NULL,
 284                 &options.password_authentication,
 285                 &options.batch_mode},
 286         {"none",
 287                 userauth_none,
 288                 NULL,
 289                 NULL,
 290                 NULL},
 291         {NULL, NULL, NULL, NULL, NULL}
 292 };
 293
 294 void
 295 ssh_userauth2(const char *local_user, const char *server_user, char *host,
 296     Sensitive *sensitive)
 297 {
 298         Authctxt authctxt;
 299         int type;
 300
 301         if (options.challenge_response_authentication)
 302                 options.kbd_interactive_authentication = 1;
 303
 304         packet_start(SSH2_MSG_SERVICE_REQUEST);
 305         packet_put_cstring("ssh-userauth");
 306         packet_send();
 307         debug("SSH2_MSG_SERVICE_REQUEST sent");
 308         packet_write_wait();
 309         type = packet_read();
 310         if (type != SSH2_MSG_SERVICE_ACCEPT)
 311                 fatal("Server denied authentication request: %d", type);
 312         if (packet_remaining() > 0) {
 313                 char *reply = packet_get_string(NULL);
 314                 debug2("service_accept: %s", reply);
 315                 xfree(reply);
 316         } else {
 317                 debug2("buggy server: service_accept w/o service");
 318         }
 319         packet_check_eom();
 320         debug("SSH2_MSG_SERVICE_ACCEPT received");
 321
 322         if (options.preferred_authentications == NULL)
 323                 options.preferred_authentications = authmethods_get();
 324
 325         /* setup authentication context */
 326         memset(&authctxt, 0, sizeof(authctxt));
 327         pubkey_prepare(&authctxt);
 328         authctxt.server_user = server_user;
 329         authctxt.local_user = local_user;
 330         authctxt.host = host;
 331         authctxt.service = "ssh-connection";            /* service name */
 332         authctxt.success = 0;
 333         authctxt.method = authmethod_lookup("none");
 334         authctxt.authlist = NULL;
 335         authctxt.methoddata = NULL;
 336         authctxt.sensitive = sensitive;
 337         authctxt.info_req_seen = 0;
 338         if (authctxt.method == NULL)
 339                 fatal("ssh_userauth2: internal error: cannot send userauth none request");
 340
 341         /* initial userauth request */
 342         userauth_none(&authctxt);
 343
 344         dispatch_init(&input_userauth_error);
 345         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
 346         dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
 347         dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
 348         dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt);     /* loop until success */
 349
 350         pubkey_cleanup(&authctxt);
 351         dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
 352
 353         debug("Authentication succeeded (%s).", authctxt.method->name);
 354 }
 355
 356 void
 357 userauth(Authctxt *authctxt, char *authlist)
 358 {
 359         if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
 360                 authctxt->method->cleanup(authctxt);
 361
 362         if (authctxt->methoddata) {
 363                 xfree(authctxt->methoddata);
 364                 authctxt->methoddata = NULL;
 365         }
 366         if (authlist == NULL) {
 367                 authlist = authctxt->authlist;
 368         } else {
 369                 if (authctxt->authlist)
 370                         xfree(authctxt->authlist);
 371                 authctxt->authlist = authlist;
 372         }
 373         for (;;) {
 374                 Authmethod *method = authmethod_get(authlist);
 375                 if (method == NULL)
 376                         fatal("Permission denied (%s).", authlist);
 377                 authctxt->method = method;
 378
 379                 /* reset the per method handler */
 380                 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
 381                     SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
 382
 383                 /* and try new method */
 384                 if (method->userauth(authctxt) != 0) {
 385                         debug2("we sent a %s packet, wait for reply", method->name);
 386                         break;
 387                 } else {
 388                         debug2("we did not send a packet, disable method");
 389                         method->enabled = NULL;
 390                 }
 391         }
 392 }
 393
 394 /* ARGSUSED */
 395 void
 396 input_userauth_error(int type, u_int32_t seq, void *ctxt)
 397 {
 398         fatal("input_userauth_error: bad message during authentication: "
 399             "type %d", type);
 400 }
 401
 402 /* ARGSUSED */
 403 void
 404 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
 405 {
 406         char *msg, *raw, *lang;
 407         u_int len;
 408
 409         debug3("input_userauth_banner");
 410         raw = packet_get_string(&len);
 411         lang = packet_get_string(NULL);
 412         if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) {
 413                 if (len > 65536)
 414                         len = 65536;
 415                 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */
 416                 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL);
 417                 fprintf(stderr, "%s", msg);
 418                 xfree(msg);
 419         }
 420         xfree(raw);
 421         xfree(lang);
 422 }
 423
 424 /* ARGSUSED */
 425 void
 426 input_userauth_success(int type, u_int32_t seq, void *ctxt)
 427 {
 428         Authctxt *authctxt = ctxt;
 429         if (authctxt == NULL)
 430                 fatal("input_userauth_success: no authentication context");
 431         if (authctxt->authlist) {
 432                 xfree(authctxt->authlist);
 433                 authctxt->authlist = NULL;
 434         }
 435         if (authctxt->methoddata) {
 436                 xfree(authctxt->methoddata);
 437                 authctxt->methoddata = NULL;
 438         }
 439         authctxt->success = 1;                  /* break out */
 440 }
 441
 442 /* ARGSUSED */
 443 void
 444 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
 445 {
 446         Authctxt *authctxt = ctxt;
 447         char *authlist = NULL;
 448         int partial;
 449
 450         if (authctxt == NULL)
 451                 fatal("input_userauth_failure: no authentication context");
 452
 453         authlist = packet_get_string(NULL);
 454         partial = packet_get_char();
 455         packet_check_eom();
 456
 457         if (partial != 0)
 458                 logit("Authenticated with partial success.");
 459         debug("Authentications that can continue: %s", authlist);
 460
 461         userauth(authctxt, authlist);
 462 }
 463
 464 /* ARGSUSED */
 465 void
 466 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
 467 {
 468         Authctxt *authctxt = ctxt;
 469         Key *key = NULL;
 470         Identity *id = NULL;
 471         Buffer b;
 472         int pktype, sent = 0;
 473         u_int alen, blen;
 474         char *pkalg, *fp;
 475         u_char *pkblob;
 476
 477         if (authctxt == NULL)
 478                 fatal("input_userauth_pk_ok: no authentication context");
 479         if (datafellows & SSH_BUG_PKOK) {
 480                 /* this is similar to SSH_BUG_PKAUTH */
 481                 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
 482                 pkblob = packet_get_string(&blen);
 483                 buffer_init(&b);
 484                 buffer_append(&b, pkblob, blen);
 485                 pkalg = buffer_get_string(&b, &alen);
 486                 buffer_free(&b);
 487         } else {
 488                 pkalg = packet_get_string(&alen);
 489                 pkblob = packet_get_string(&blen);
 490         }
 491         packet_check_eom();
 492
 493         debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
 494
 495         if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
 496                 debug("unknown pkalg %s", pkalg);
 497                 goto done;
 498         }
 499         if ((key = key_from_blob(pkblob, blen)) == NULL) {
 500                 debug("no key from blob. pkalg %s", pkalg);
 501                 goto done;
 502         }
 503         if (key->type != pktype) {
 504                 error("input_userauth_pk_ok: type mismatch "
 505                     "for decoded key (received %d, expected %d)",
 506                     key->type, pktype);
 507                 goto done;
 508         }
 509         fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
 510         debug2("input_userauth_pk_ok: fp %s", fp);
 511         xfree(fp);
 512
 513         /*
 514          * search keys in the reverse order, because last candidate has been
 515          * moved to the end of the queue.  this also avoids confusion by
 516          * duplicate keys
 517          */
 518         TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
 519                 if (key_equal(key, id->key)) {
 520                         sent = sign_and_send_pubkey(authctxt, id);
 521                         break;
 522                 }
 523         }
 524 done:
 525         if (key != NULL)
 526                 key_free(key);
 527         xfree(pkalg);
 528         xfree(pkblob);
 529
 530         /* try another method if we did not send a packet */
 531         if (sent == 0)
 532                 userauth(authctxt, NULL);
 533 }
 534
 535 #ifdef GSSAPI
 536 int
 537 userauth_gssapi(Authctxt *authctxt)
 538 {
 539         Gssctxt *gssctxt = NULL;
 540         static gss_OID_set gss_supported = NULL;
 541         static u_int mech = 0;
 542         OM_uint32 min;
 543         int ok = 0;
 544
 545         /* Try one GSSAPI method at a time, rather than sending them all at
 546          * once. */
 547
 548         if (gss_supported == NULL)
 549                 gss_indicate_mechs(&min, &gss_supported);
 550
 551         /* Check to see if the mechanism is usable before we offer it */
 552         while (mech < gss_supported->count && !ok) {
 553                 /* My DER encoding requires length<128 */
 554                 if (gss_supported->elements[mech].length < 128 &&
 555                     ssh_gssapi_check_mechanism(&gssctxt,
 556                     &gss_supported->elements[mech], authctxt->host)) {
 557                         ok = 1; /* Mechanism works */
 558                 } else {
 559                         mech++;
 560                 }
 561         }
 562
 563         if (!ok)
 564                 return 0;
 565
 566         authctxt->methoddata=(void *)gssctxt;
 567
 568         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 569         packet_put_cstring(authctxt->server_user);
 570         packet_put_cstring(authctxt->service);
 571         packet_put_cstring(authctxt->method->name);
 572
 573         packet_put_int(1);
 574
 575         packet_put_int((gss_supported->elements[mech].length) + 2);
 576         packet_put_char(SSH_GSS_OIDTYPE);
 577         packet_put_char(gss_supported->elements[mech].length);
 578         packet_put_raw(gss_supported->elements[mech].elements,
 579             gss_supported->elements[mech].length);
 580
 581         packet_send();
 582
 583         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
 584         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
 585         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
 586         dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
 587
 588         mech++; /* Move along to next candidate */
 589
 590         return 1;
 591 }
 592
 593 static OM_uint32
 594 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
 595 {
 596         Authctxt *authctxt = ctxt;
 597         Gssctxt *gssctxt = authctxt->methoddata;
 598         gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
 599         gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
 600         gss_buffer_desc gssbuf;
 601         OM_uint32 status, ms, flags;
 602         Buffer b;
 603
 604         status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
 605             recv_tok, &send_tok, &flags);
 606
 607         if (send_tok.length > 0) {
 608                 if (GSS_ERROR(status))
 609                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
 610                 else
 611                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
 612
 613                 packet_put_string(send_tok.value, send_tok.length);
 614                 packet_send();
 615                 gss_release_buffer(&ms, &send_tok);
 616         }
 617
 618         if (status == GSS_S_COMPLETE) {
 619                 /* send either complete or MIC, depending on mechanism */
 620                 if (!(flags & GSS_C_INTEG_FLAG)) {
 621                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
 622                         packet_send();
 623                 } else {
 624                         ssh_gssapi_buildmic(&b, authctxt->server_user,
 625                             authctxt->service, "gssapi-with-mic");
 626
 627                         gssbuf.value = buffer_ptr(&b);
 628                         gssbuf.length = buffer_len(&b);
 629
 630                         status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
 631
 632                         if (!GSS_ERROR(status)) {
 633                                 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
 634                                 packet_put_string(mic.value, mic.length);
 635
 636                                 packet_send();
 637                         }
 638
 639                         buffer_free(&b);
 640                         gss_release_buffer(&ms, &mic);
 641                 }
 642         }
 643
 644         return status;
 645 }
 646
 647 /* ARGSUSED */
 648 void
 649 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
 650 {
 651         Authctxt *authctxt = ctxt;
 652         Gssctxt *gssctxt;
 653         int oidlen;
 654         char *oidv;
 655
 656         if (authctxt == NULL)
 657                 fatal("input_gssapi_response: no authentication context");
 658         gssctxt = authctxt->methoddata;
 659
 660         /* Setup our OID */
 661         oidv = packet_get_string(&oidlen);
 662
 663         if (oidlen <= 2 ||
 664             oidv[0] != SSH_GSS_OIDTYPE ||
 665             oidv[1] != oidlen - 2) {
 666                 xfree(oidv);
 667                 debug("Badly encoded mechanism OID received");
 668                 userauth(authctxt, NULL);
 669                 return;
 670         }
 671
 672         if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
 673                 fatal("Server returned different OID than expected");
 674
 675         packet_check_eom();
 676
 677         xfree(oidv);
 678
 679         if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
 680                 /* Start again with next method on list */
 681                 debug("Trying to start again");
 682                 userauth(authctxt, NULL);
 683                 return;
 684         }
 685 }
 686
 687 /* ARGSUSED */
 688 void
 689 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
 690 {
 691         Authctxt *authctxt = ctxt;
 692         gss_buffer_desc recv_tok;
 693         OM_uint32 status;
 694         u_int slen;
 695
 696         if (authctxt == NULL)
 697                 fatal("input_gssapi_response: no authentication context");
 698
 699         recv_tok.value = packet_get_string(&slen);
 700         recv_tok.length = slen; /* safe typecast */
 701
 702         packet_check_eom();
 703
 704         status = process_gssapi_token(ctxt, &recv_tok);
 705
 706         xfree(recv_tok.value);
 707
 708         if (GSS_ERROR(status)) {
 709                 /* Start again with the next method in the list */
 710                 userauth(authctxt, NULL);
 711                 return;
 712         }
 713 }
 714
 715 /* ARGSUSED */
 716 void
 717 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
 718 {
 719         Authctxt *authctxt = ctxt;
 720         Gssctxt *gssctxt;
 721         gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
 722         gss_buffer_desc recv_tok;
 723         OM_uint32 status, ms;
 724         u_int len;
 725
 726         if (authctxt == NULL)
 727                 fatal("input_gssapi_response: no authentication context");
 728         gssctxt = authctxt->methoddata;
 729
 730         recv_tok.value = packet_get_string(&len);
 731         recv_tok.length = len;
 732
 733         packet_check_eom();
 734
 735         /* Stick it into GSSAPI and see what it says */
 736         status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
 737             &recv_tok, &send_tok, NULL);
 738
 739         xfree(recv_tok.value);
 740         gss_release_buffer(&ms, &send_tok);
 741
 742         /* Server will be returning a failed packet after this one */
 743 }
 744
 745 /* ARGSUSED */
 746 void
 747 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
 748 {
 749         OM_uint32 maj, min;
 750         char *msg;
 751         char *lang;
 752
 753         maj=packet_get_int();
 754         min=packet_get_int();
 755         msg=packet_get_string(NULL);
 756         lang=packet_get_string(NULL);
 757
 758         packet_check_eom();
 759
 760         debug("Server GSSAPI Error:\n%s", msg);
 761         xfree(msg);
 762         xfree(lang);
 763 }
 764 #endif /* GSSAPI */
 765
 766 int
 767 userauth_none(Authctxt *authctxt)
 768 {
 769         /* initial userauth request */
 770         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 771         packet_put_cstring(authctxt->server_user);
 772         packet_put_cstring(authctxt->service);
 773         packet_put_cstring(authctxt->method->name);
 774         packet_send();
 775         return 1;
 776 }
 777
 778 int
 779 userauth_passwd(Authctxt *authctxt)
 780 {
 781         static int attempt = 0;
 782         char prompt[150];
 783         char *password;
 784
 785         if (attempt++ >= options.number_of_password_prompts)
 786                 return 0;
 787
 788         if (attempt != 1)
 789                 error("Permission denied, please try again.");
 790
 791         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
 792             authctxt->server_user, authctxt->host);
 793         password = read_passphrase(prompt, 0);
 794         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 795         packet_put_cstring(authctxt->server_user);
 796         packet_put_cstring(authctxt->service);
 797         packet_put_cstring(authctxt->method->name);
 798         packet_put_char(0);
 799         packet_put_cstring(password);
 800         memset(password, 0, strlen(password));
 801         xfree(password);
 802         packet_add_padding(64);
 803         packet_send();
 804
 805         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
 806             &input_userauth_passwd_changereq);
 807
 808         return 1;
 809 }
 810
 811 /*
 812  * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
 813  */
 814 /* ARGSUSED */
 815 void
 816 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
 817 {
 818         Authctxt *authctxt = ctxt;
 819         char *info, *lang, *password = NULL, *retype = NULL;
 820         char prompt[150];
 821
 822         debug2("input_userauth_passwd_changereq");
 823
 824         if (authctxt == NULL)
 825                 fatal("input_userauth_passwd_changereq: "
 826                     "no authentication context");
 827
 828         info = packet_get_string(NULL);
 829         lang = packet_get_string(NULL);
 830         if (strlen(info) > 0)
 831                 logit("%s", info);
 832         xfree(info);
 833         xfree(lang);
 834         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 835         packet_put_cstring(authctxt->server_user);
 836         packet_put_cstring(authctxt->service);
 837         packet_put_cstring(authctxt->method->name);
 838         packet_put_char(1);                     /* additional info */
 839         snprintf(prompt, sizeof(prompt),
 840             "Enter %.30s@%.128s's old password: ",
 841             authctxt->server_user, authctxt->host);
 842         password = read_passphrase(prompt, 0);
 843         packet_put_cstring(password);
 844         memset(password, 0, strlen(password));
 845         xfree(password);
 846         password = NULL;
 847         while (password == NULL) {
 848                 snprintf(prompt, sizeof(prompt),
 849                     "Enter %.30s@%.128s's new password: ",
 850                     authctxt->server_user, authctxt->host);
 851                 password = read_passphrase(prompt, RP_ALLOW_EOF);
 852                 if (password == NULL) {
 853                         /* bail out */
 854                         return;
 855                 }
 856                 snprintf(prompt, sizeof(prompt),
 857                     "Retype %.30s@%.128s's new password: ",
 858                     authctxt->server_user, authctxt->host);
 859                 retype = read_passphrase(prompt, 0);
 860                 if (strcmp(password, retype) != 0) {
 861                         memset(password, 0, strlen(password));
 862                         xfree(password);
 863                         logit("Mismatch; try again, EOF to quit.");
 864                         password = NULL;
 865                 }
 866                 memset(retype, 0, strlen(retype));
 867                 xfree(retype);
 868         }
 869         packet_put_cstring(password);
 870         memset(password, 0, strlen(password));
 871         xfree(password);
 872         packet_add_padding(64);
 873         packet_send();
 874
 875         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
 876             &input_userauth_passwd_changereq);
 877 }
 878
 879 #ifdef JPAKE
 880 static char *
 881 pw_encrypt(const char *password, const char *crypt_scheme, const char *salt)
 882 {
 883         /* OpenBSD crypt(3) handles all of these */
 884         if (strcmp(crypt_scheme, "crypt") == 0 ||
 885             strcmp(crypt_scheme, "bcrypt") == 0 ||
 886             strcmp(crypt_scheme, "md5crypt") == 0 ||
 887             strcmp(crypt_scheme, "crypt-extended") == 0)
 888                 return xstrdup(crypt(password, salt));
 889         error("%s: unsupported password encryption scheme \"%.100s\"",
 890             __func__, crypt_scheme);
 891         return NULL;
 892 }
 893
 894 static BIGNUM *
 895 jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme,
 896     const char *salt)
 897 {
 898         char prompt[256], *password, *crypted;
 899         u_char *secret;
 900         u_int secret_len;
 901         BIGNUM *ret;
 902
 903         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ",
 904             authctxt->server_user, authctxt->host);
 905         password = read_passphrase(prompt, 0);
 906
 907         if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) {
 908                 logit("Disabling %s authentication", authctxt->method->name);
 909                 authctxt->method->enabled = NULL;
 910                 /* Continue with an empty password to fail gracefully */
 911                 crypted = xstrdup("");
 912         }
 913
 914 #ifdef JPAKE_DEBUG
 915         debug3("%s: salt = %s", __func__, salt);
 916         debug3("%s: scheme = %s", __func__, crypt_scheme);
 917         debug3("%s: crypted = %s", __func__, crypted);
 918 #endif
 919
 920         if (hash_buffer(crypted, strlen(crypted), EVP_sha256(),
 921             &secret, &secret_len) != 0)
 922                 fatal("%s: hash_buffer", __func__);
 923
 924         bzero(password, strlen(password));
 925         bzero(crypted, strlen(crypted));
 926         xfree(password);
 927         xfree(crypted);
 928
 929         if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL)
 930                 fatal("%s: BN_bin2bn (secret)", __func__);
 931         bzero(secret, secret_len);
 932         xfree(secret);
 933
 934         return ret;
 935 }
 936
 937 /* ARGSUSED */
 938 void
 939 input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt)
 940 {
 941         Authctxt *authctxt = ctxt;
 942         struct jpake_ctx *pctx = authctxt->methoddata;
 943         u_char *x3_proof, *x4_proof, *x2_s_proof;
 944         u_int x3_proof_len, x4_proof_len, x2_s_proof_len;
 945         char *crypt_scheme, *salt;
 946
 947         /* Disable this message */
 948         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL);
 949
 950         if ((pctx->g_x3 = BN_new()) == NULL ||
 951             (pctx->g_x4 = BN_new()) == NULL)
 952                 fatal("%s: BN_new", __func__);
 953
 954         /* Fetch step 1 values */
 955         crypt_scheme = packet_get_string(NULL);
 956         salt = packet_get_string(NULL);
 957         pctx->server_id = packet_get_string(&pctx->server_id_len);
 958         packet_get_bignum2(pctx->g_x3);
 959         packet_get_bignum2(pctx->g_x4);
 960         x3_proof = packet_get_string(&x3_proof_len);
 961         x4_proof = packet_get_string(&x4_proof_len);
 962         packet_check_eom();
 963
 964         JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__));
 965
 966         /* Obtain password and derive secret */
 967         pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt);
 968         bzero(crypt_scheme, strlen(crypt_scheme));
 969         bzero(salt, strlen(salt));
 970         xfree(crypt_scheme);
 971         xfree(salt);
 972         JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__));
 973
 974         /* Calculate step 2 values */
 975         jpake_step2(pctx->grp, pctx->s, pctx->g_x1,
 976             pctx->g_x3, pctx->g_x4, pctx->x2,
 977             pctx->server_id, pctx->server_id_len,
 978             pctx->client_id, pctx->client_id_len,
 979             x3_proof, x3_proof_len,
 980             x4_proof, x4_proof_len,
 981             &pctx->a,
 982             &x2_s_proof, &x2_s_proof_len);
 983
 984         bzero(x3_proof, x3_proof_len);
 985         bzero(x4_proof, x4_proof_len);
 986         xfree(x3_proof);
 987         xfree(x4_proof);
 988
 989         JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__));
 990
 991         /* Send values for step 2 */
 992         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2);
 993         packet_put_bignum2(pctx->a);
 994         packet_put_string(x2_s_proof, x2_s_proof_len);
 995         packet_send();
 996
 997         bzero(x2_s_proof, x2_s_proof_len);
 998         xfree(x2_s_proof);
 999
1000         /* Expect step 2 packet from peer */
1001         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2,
1002             input_userauth_jpake_server_step2);
1003 }
1004
1005 /* ARGSUSED */
1006 void
1007 input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt)
1008 {
1009         Authctxt *authctxt = ctxt;
1010         struct jpake_ctx *pctx = authctxt->methoddata;
1011         u_char *x4_s_proof;
1012         u_int x4_s_proof_len;
1013
1014         /* Disable this message */
1015         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL);
1016
1017         if ((pctx->b = BN_new()) == NULL)
1018                 fatal("%s: BN_new", __func__);
1019
1020         /* Fetch step 2 values */
1021         packet_get_bignum2(pctx->b);
1022         x4_s_proof = packet_get_string(&x4_s_proof_len);
1023         packet_check_eom();
1024
1025         JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__));
1026
1027         /* Derive shared key and calculate confirmation hash */
1028         jpake_key_confirm(pctx->grp, pctx->s, pctx->b,
1029             pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4,
1030             pctx->client_id, pctx->client_id_len,
1031             pctx->server_id, pctx->server_id_len,
1032             session_id2, session_id2_len,
1033             x4_s_proof, x4_s_proof_len,
1034             &pctx->k,
1035             &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len);
1036
1037         bzero(x4_s_proof, x4_s_proof_len);
1038         xfree(x4_s_proof);
1039
1040         JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__));
1041
1042         /* Send key confirmation proof */
1043         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM);
1044         packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len);
1045         packet_send();
1046
1047         /* Expect confirmation from peer */
1048         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM,
1049             input_userauth_jpake_server_confirm);
1050 }
1051
1052 /* ARGSUSED */
1053 void
1054 input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt)
1055 {
1056         Authctxt *authctxt = ctxt;
1057         struct jpake_ctx *pctx = authctxt->methoddata;
1058
1059         /* Disable this message */
1060         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL);
1061
1062         pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len);
1063         packet_check_eom();
1064
1065         JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__));
1066
1067         /* Verify expected confirmation hash */
1068         if (jpake_check_confirm(pctx->k,
1069             pctx->server_id, pctx->server_id_len,
1070             session_id2, session_id2_len,
1071             pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1)
1072                 debug("%s: %s success", __func__, authctxt->method->name);
1073         else {
1074                 debug("%s: confirmation mismatch", __func__);
1075                 /* XXX stash this so if auth succeeds then we can warn/kill */
1076         }
1077
1078         userauth_jpake_cleanup(authctxt);
1079 }
1080 #endif /* JPAKE */
1081
1082 static int
1083 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
1084     u_char *data, u_int datalen)
1085 {
1086         Key *prv;
1087         int ret;
1088
1089         /* the agent supports this key */
1090         if (id->ac)
1091                 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
1092                     data, datalen));
1093         /*
1094          * we have already loaded the private key or
1095          * the private key is stored in external hardware
1096          */
1097         if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
1098                 return (key_sign(id->key, sigp, lenp, data, datalen));
1099         /* load the private key from the file */
1100         if ((prv = load_identity_file(id->filename)) == NULL)
1101                 return (-1);
1102         ret = key_sign(prv, sigp, lenp, data, datalen);
1103         key_free(prv);
1104         return (ret);
1105 }
1106
1107 static int
1108 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
1109 {
1110         Buffer b;
1111         u_char *blob, *signature;
1112         u_int bloblen, slen;
1113         u_int skip = 0;
1114         int ret = -1;
1115         int have_sig = 1;
1116
1117         debug3("sign_and_send_pubkey");
1118
1119         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1120                 /* we cannot handle this key */
1121                 debug3("sign_and_send_pubkey: cannot handle key");
1122                 return 0;
1123         }
1124         /* data to be signed */
1125         buffer_init(&b);
1126         if (datafellows & SSH_OLD_SESSIONID) {
1127                 buffer_append(&b, session_id2, session_id2_len);
1128                 skip = session_id2_len;
1129         } else {
1130                 buffer_put_string(&b, session_id2, session_id2_len);
1131                 skip = buffer_len(&b);
1132         }
1133         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1134         buffer_put_cstring(&b, authctxt->server_user);
1135         buffer_put_cstring(&b,
1136             datafellows & SSH_BUG_PKSERVICE ?
1137             "ssh-userauth" :
1138             authctxt->service);
1139         if (datafellows & SSH_BUG_PKAUTH) {
1140                 buffer_put_char(&b, have_sig);
1141         } else {
1142                 buffer_put_cstring(&b, authctxt->method->name);
1143                 buffer_put_char(&b, have_sig);
1144                 buffer_put_cstring(&b, key_ssh_name(id->key));
1145         }
1146         buffer_put_string(&b, blob, bloblen);
1147
1148         /* generate signature */
1149         ret = identity_sign(id, &signature, &slen,
1150             buffer_ptr(&b), buffer_len(&b));
1151         if (ret == -1) {
1152                 xfree(blob);
1153                 buffer_free(&b);
1154                 return 0;
1155         }
1156 #ifdef DEBUG_PK
1157         buffer_dump(&b);
1158 #endif
1159         if (datafellows & SSH_BUG_PKSERVICE) {
1160                 buffer_clear(&b);
1161                 buffer_append(&b, session_id2, session_id2_len);
1162                 skip = session_id2_len;
1163                 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1164                 buffer_put_cstring(&b, authctxt->server_user);
1165                 buffer_put_cstring(&b, authctxt->service);
1166                 buffer_put_cstring(&b, authctxt->method->name);
1167                 buffer_put_char(&b, have_sig);
1168                 if (!(datafellows & SSH_BUG_PKAUTH))
1169                         buffer_put_cstring(&b, key_ssh_name(id->key));
1170                 buffer_put_string(&b, blob, bloblen);
1171         }
1172         xfree(blob);
1173
1174         /* append signature */
1175         buffer_put_string(&b, signature, slen);
1176         xfree(signature);
1177
1178         /* skip session id and packet type */
1179         if (buffer_len(&b) < skip + 1)
1180                 fatal("userauth_pubkey: internal error");
1181         buffer_consume(&b, skip + 1);
1182
1183         /* put remaining data from buffer into packet */
1184         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1185         packet_put_raw(buffer_ptr(&b), buffer_len(&b));
1186         buffer_free(&b);
1187         packet_send();
1188
1189         return 1;
1190 }
1191
1192 static int
1193 send_pubkey_test(Authctxt *authctxt, Identity *id)
1194 {
1195         u_char *blob;
1196         u_int bloblen, have_sig = 0;
1197
1198         debug3("send_pubkey_test");
1199
1200         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1201                 /* we cannot handle this key */
1202                 debug3("send_pubkey_test: cannot handle key");
1203                 return 0;
1204         }
1205         /* register callback for USERAUTH_PK_OK message */
1206         dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
1207
1208         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1209         packet_put_cstring(authctxt->server_user);
1210         packet_put_cstring(authctxt->service);
1211         packet_put_cstring(authctxt->method->name);
1212         packet_put_char(have_sig);
1213         if (!(datafellows & SSH_BUG_PKAUTH))
1214                 packet_put_cstring(key_ssh_name(id->key));
1215         packet_put_string(blob, bloblen);
1216         xfree(blob);
1217         packet_send();
1218         return 1;
1219 }
1220
1221 static Key *
1222 load_identity_file(char *filename)
1223 {
1224         Key *private;
1225         char prompt[300], *passphrase;
1226         int perm_ok, quit, i;
1227         struct stat st;
1228
1229         if (stat(filename, &st) < 0) {
1230                 debug3("no such identity: %s", filename);
1231                 return NULL;
1232         }
1233         private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
1234         if (!perm_ok)
1235                 return NULL;
1236         if (private == NULL) {
1237                 if (options.batch_mode)
1238                         return NULL;
1239                 snprintf(prompt, sizeof prompt,
1240                     "Enter passphrase for key '%.100s': ", filename);
1241                 for (i = 0; i < options.number_of_password_prompts; i++) {
1242                         passphrase = read_passphrase(prompt, 0);
1243                         if (strcmp(passphrase, "") != 0) {
1244                                 private = key_load_private_type(KEY_UNSPEC,
1245                                     filename, passphrase, NULL, NULL);
1246                                 quit = 0;
1247                         } else {
1248                                 debug2("no passphrase given, try next key");
1249                                 quit = 1;
1250                         }
1251                         memset(passphrase, 0, strlen(passphrase));
1252                         xfree(passphrase);
1253                         if (private != NULL || quit)
1254                                 break;
1255                         debug2("bad passphrase given, try again...");
1256                 }
1257         }
1258         return private;
1259 }
1260
1261 /*
1262  * try keys in the following order:
1263  *      1. agent keys that are found in the config file
1264  *      2. other agent keys
1265  *      3. keys that are only listed in the config file
1266  */
1267 static void
1268 pubkey_prepare(Authctxt *authctxt)
1269 {
1270         Identity *id;
1271         Idlist agent, files, *preferred;
1272         Key *key;
1273         AuthenticationConnection *ac;
1274         char *comment;
1275         int i, found;
1276
1277         TAILQ_INIT(&agent);     /* keys from the agent */
1278         TAILQ_INIT(&files);     /* keys from the config file */
1279         preferred = &authctxt->keys;
1280         TAILQ_INIT(preferred);  /* preferred order of keys */
1281
1282         /* list of keys stored in the filesystem */
1283         for (i = 0; i < options.num_identity_files; i++) {
1284                 key = options.identity_keys[i];
1285                 if (key && key->type == KEY_RSA1)
1286                         continue;
1287                 options.identity_keys[i] = NULL;
1288                 id = xcalloc(1, sizeof(*id));
1289                 id->key = key;
1290                 id->filename = xstrdup(options.identity_files[i]);
1291                 TAILQ_INSERT_TAIL(&files, id, next);
1292         }
1293         /* list of keys supported by the agent */
1294         if ((ac = ssh_get_authentication_connection())) {
1295                 for (key = ssh_get_first_identity(ac, &comment, 2);
1296                     key != NULL;
1297                     key = ssh_get_next_identity(ac, &comment, 2)) {
1298                         found = 0;
1299                         TAILQ_FOREACH(id, &files, next) {
1300                                 /* agent keys from the config file are preferred */
1301                                 if (key_equal(key, id->key)) {
1302                                         key_free(key);
1303                                         xfree(comment);
1304                                         TAILQ_REMOVE(&files, id, next);
1305                                         TAILQ_INSERT_TAIL(preferred, id, next);
1306                                         id->ac = ac;
1307                                         found = 1;
1308                                         break;
1309                                 }
1310                         }
1311                         if (!found && !options.identities_only) {
1312                                 id = xcalloc(1, sizeof(*id));
1313                                 id->key = key;
1314                                 id->filename = comment;
1315                                 id->ac = ac;
1316                                 TAILQ_INSERT_TAIL(&agent, id, next);
1317                         }
1318                 }
1319                 /* append remaining agent keys */
1320                 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1321                         TAILQ_REMOVE(&agent, id, next);
1322                         TAILQ_INSERT_TAIL(preferred, id, next);
1323                 }
1324                 authctxt->agent = ac;
1325         }
1326         /* append remaining keys from the config file */
1327         for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1328                 TAILQ_REMOVE(&files, id, next);
1329                 TAILQ_INSERT_TAIL(preferred, id, next);
1330         }
1331         TAILQ_FOREACH(id, preferred, next) {
1332                 debug2("key: %s (%p)", id->filename, id->key);
1333         }
1334 }
1335
1336 static void
1337 pubkey_cleanup(Authctxt *authctxt)
1338 {
1339         Identity *id;
1340
1341         if (authctxt->agent != NULL)
1342                 ssh_close_authentication_connection(authctxt->agent);
1343         for (id = TAILQ_FIRST(&authctxt->keys); id;
1344             id = TAILQ_FIRST(&authctxt->keys)) {
1345                 TAILQ_REMOVE(&authctxt->keys, id, next);
1346                 if (id->key)
1347                         key_free(id->key);
1348                 if (id->filename)
1349                         xfree(id->filename);
1350                 xfree(id);
1351         }
1352 }
1353
1354 int
1355 userauth_pubkey(Authctxt *authctxt)
1356 {
1357         Identity *id;
1358         int sent = 0;
1359
1360         while ((id = TAILQ_FIRST(&authctxt->keys))) {
1361                 if (id->tried++)
1362                         return (0);
1363                 /* move key to the end of the queue */
1364                 TAILQ_REMOVE(&authctxt->keys, id, next);
1365                 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1366                 /*
1367                  * send a test message if we have the public key. for
1368                  * encrypted keys we cannot do this and have to load the
1369                  * private key instead
1370                  */
1371                 if (id->key && id->key->type != KEY_RSA1) {
1372                         debug("Offering public key: %s", id->filename);
1373                         sent = send_pubkey_test(authctxt, id);
1374                 } else if (id->key == NULL) {
1375                         debug("Trying private key: %s", id->filename);
1376                         id->key = load_identity_file(id->filename);
1377                         if (id->key != NULL) {
1378                                 id->isprivate = 1;
1379                                 sent = sign_and_send_pubkey(authctxt, id);
1380                                 key_free(id->key);
1381                                 id->key = NULL;
1382                         }
1383                 }
1384                 if (sent)
1385                         return (sent);
1386         }
1387         return (0);
1388 }
1389
1390 /*
1391  * Send userauth request message specifying keyboard-interactive method.
1392  */
1393 int
1394 userauth_kbdint(Authctxt *authctxt)
1395 {
1396         static int attempt = 0;
1397
1398         if (attempt++ >= options.number_of_password_prompts)
1399                 return 0;
1400         /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1401         if (attempt > 1 && !authctxt->info_req_seen) {
1402                 debug3("userauth_kbdint: disable: no info_req_seen");
1403                 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1404                 return 0;
1405         }
1406
1407         debug2("userauth_kbdint");
1408         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1409         packet_put_cstring(authctxt->server_user);
1410         packet_put_cstring(authctxt->service);
1411         packet_put_cstring(authctxt->method->name);
1412         packet_put_cstring("");                                 /* lang */
1413         packet_put_cstring(options.kbd_interactive_devices ?
1414             options.kbd_interactive_devices : "");
1415         packet_send();
1416
1417         dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1418         return 1;
1419 }
1420
1421 /*
1422  * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1423  */
1424 void
1425 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1426 {
1427         Authctxt *authctxt = ctxt;
1428         char *name, *inst, *lang, *prompt, *response;
1429         u_int num_prompts, i;
1430         int echo = 0;
1431
1432         debug2("input_userauth_info_req");
1433
1434         if (authctxt == NULL)
1435                 fatal("input_userauth_info_req: no authentication context");
1436
1437         authctxt->info_req_seen = 1;
1438
1439         name = packet_get_string(NULL);
1440         inst = packet_get_string(NULL);
1441         lang = packet_get_string(NULL);
1442         if (strlen(name) > 0)
1443                 logit("%s", name);
1444         if (strlen(inst) > 0)
1445                 logit("%s", inst);
1446         xfree(name);
1447         xfree(inst);
1448         xfree(lang);
1449
1450         num_prompts = packet_get_int();
1451         /*
1452          * Begin to build info response packet based on prompts requested.
1453          * We commit to providing the correct number of responses, so if
1454          * further on we run into a problem that prevents this, we have to
1455          * be sure and clean this up and send a correct error response.
1456          */
1457         packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1458         packet_put_int(num_prompts);
1459
1460         debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1461         for (i = 0; i < num_prompts; i++) {
1462                 prompt = packet_get_string(NULL);
1463                 echo = packet_get_char();
1464
1465                 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1466
1467                 packet_put_cstring(response);
1468                 memset(response, 0, strlen(response));
1469                 xfree(response);
1470                 xfree(prompt);
1471         }
1472         packet_check_eom(); /* done with parsing incoming message. */
1473
1474         packet_add_padding(64);
1475         packet_send();
1476 }
1477
1478 static int
1479 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1480     u_char *data, u_int datalen)
1481 {
1482         Buffer b;
1483         struct stat st;
1484         pid_t pid;
1485         int to[2], from[2], status, version = 2;
1486
1487         debug2("ssh_keysign called");
1488
1489         if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1490                 error("ssh_keysign: no installed: %s", strerror(errno));
1491                 return -1;
1492         }
1493         if (fflush(stdout) != 0)
1494                 error("ssh_keysign: fflush: %s", strerror(errno));
1495         if (pipe(to) < 0) {
1496                 error("ssh_keysign: pipe: %s", strerror(errno));
1497                 return -1;
1498         }
1499         if (pipe(from) < 0) {
1500                 error("ssh_keysign: pipe: %s", strerror(errno));
1501                 return -1;
1502         }
1503         if ((pid = fork()) < 0) {
1504                 error("ssh_keysign: fork: %s", strerror(errno));
1505                 return -1;
1506         }
1507         if (pid == 0) {
1508                 permanently_drop_suid(getuid());
1509                 close(from[0]);
1510                 if (dup2(from[1], STDOUT_FILENO) < 0)
1511                         fatal("ssh_keysign: dup2: %s", strerror(errno));
1512                 close(to[1]);
1513                 if (dup2(to[0], STDIN_FILENO) < 0)
1514                         fatal("ssh_keysign: dup2: %s", strerror(errno));
1515                 close(from[1]);
1516                 close(to[0]);
1517                 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1518                 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1519                     strerror(errno));
1520         }
1521         close(from[1]);
1522         close(to[0]);
1523
1524         buffer_init(&b);
1525         buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1526         buffer_put_string(&b, data, datalen);
1527         if (ssh_msg_send(to[1], version, &b) == -1)
1528                 fatal("ssh_keysign: couldn't send request");
1529
1530         if (ssh_msg_recv(from[0], &b) < 0) {
1531                 error("ssh_keysign: no reply");
1532                 buffer_free(&b);
1533                 return -1;
1534         }
1535         close(from[0]);
1536         close(to[1]);
1537
1538         while (waitpid(pid, &status, 0) < 0)
1539                 if (errno != EINTR)
1540                         break;
1541
1542         if (buffer_get_char(&b) != version) {
1543                 error("ssh_keysign: bad version");
1544                 buffer_free(&b);
1545                 return -1;
1546         }
1547         *sigp = buffer_get_string(&b, lenp);
1548         buffer_free(&b);
1549
1550         return 0;
1551 }
1552
1553 int
1554 userauth_hostbased(Authctxt *authctxt)
1555 {
1556         Key *private = NULL;
1557         Sensitive *sensitive = authctxt->sensitive;
1558         Buffer b;
1559         u_char *signature, *blob;
1560         char *chost, *pkalg, *p, myname[NI_MAXHOST];
1561         const char *service;
1562         u_int blen, slen;
1563         int ok, i, len, found = 0;
1564
1565         /* check for a useful key */
1566         for (i = 0; i < sensitive->nkeys; i++) {
1567                 private = sensitive->keys[i];
1568                 if (private && private->type != KEY_RSA1) {
1569                         found = 1;
1570                         /* we take and free the key */
1571                         sensitive->keys[i] = NULL;
1572                         break;
1573                 }
1574         }
1575         if (!found) {
1576                 debug("No more client hostkeys for hostbased authentication.");
1577                 return 0;
1578         }
1579         if (key_to_blob(private, &blob, &blen) == 0) {
1580                 key_free(private);
1581                 return 0;
1582         }
1583         /* figure out a name for the client host */
1584         p = NULL;
1585         if (packet_connection_is_on_socket())
1586                 p = get_local_name(packet_get_connection_in());
1587         if (p == NULL) {
1588                 if (gethostname(myname, sizeof(myname)) == -1) {
1589                         verbose("userauth_hostbased: gethostname: %s",
1590                             strerror(errno));
1591                 } else
1592                         p = xstrdup(myname);
1593         }
1594         if (p == NULL) {
1595                 error("userauth_hostbased: cannot get local ipaddr/name");
1596                 key_free(private);
1597                 xfree(blob);
1598                 return 0;
1599         }
1600         len = strlen(p) + 2;
1601         xasprintf(&chost, "%s.", p);
1602         debug2("userauth_hostbased: chost %s", chost);
1603         xfree(p);
1604
1605         service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1606             authctxt->service;
1607         pkalg = xstrdup(key_ssh_name(private));
1608         buffer_init(&b);
1609         /* construct data */
1610         buffer_put_string(&b, session_id2, session_id2_len);
1611         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1612         buffer_put_cstring(&b, authctxt->server_user);
1613         buffer_put_cstring(&b, service);
1614         buffer_put_cstring(&b, authctxt->method->name);
1615         buffer_put_cstring(&b, pkalg);
1616         buffer_put_string(&b, blob, blen);
1617         buffer_put_cstring(&b, chost);
1618         buffer_put_cstring(&b, authctxt->local_user);
1619 #ifdef DEBUG_PK
1620         buffer_dump(&b);
1621 #endif
1622         if (sensitive->external_keysign)
1623                 ok = ssh_keysign(private, &signature, &slen,
1624                     buffer_ptr(&b), buffer_len(&b));
1625         else
1626                 ok = key_sign(private, &signature, &slen,
1627                     buffer_ptr(&b), buffer_len(&b));
1628         key_free(private);
1629         buffer_free(&b);
1630         if (ok != 0) {
1631                 error("key_sign failed");
1632                 xfree(chost);
1633                 xfree(pkalg);
1634                 xfree(blob);
1635                 return 0;
1636         }
1637         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1638         packet_put_cstring(authctxt->server_user);
1639         packet_put_cstring(authctxt->service);
1640         packet_put_cstring(authctxt->method->name);
1641         packet_put_cstring(pkalg);
1642         packet_put_string(blob, blen);
1643         packet_put_cstring(chost);
1644         packet_put_cstring(authctxt->local_user);
1645         packet_put_string(signature, slen);
1646         memset(signature, 's', slen);
1647         xfree(signature);
1648         xfree(chost);
1649         xfree(pkalg);
1650         xfree(blob);
1651
1652         packet_send();
1653         return 1;
1654 }
1655
1656 #ifdef JPAKE
1657 int
1658 userauth_jpake(Authctxt *authctxt)
1659 {
1660         struct jpake_ctx *pctx;
1661         u_char *x1_proof, *x2_proof;
1662         u_int x1_proof_len, x2_proof_len;
1663         static int attempt = 0; /* XXX share with userauth_password's? */
1664
1665         if (attempt++ >= options.number_of_password_prompts)
1666                 return 0;
1667         if (attempt != 1)
1668                 error("Permission denied, please try again.");
1669
1670         if (authctxt->methoddata != NULL)
1671                 fatal("%s: authctxt->methoddata already set (%p)",
1672                     __func__, authctxt->methoddata);
1673
1674         authctxt->methoddata = pctx = jpake_new();
1675
1676         /*
1677          * Send request immediately, to get the protocol going while
1678          * we do the initial computations.
1679          */
1680         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1681         packet_put_cstring(authctxt->server_user);
1682         packet_put_cstring(authctxt->service);
1683         packet_put_cstring(authctxt->method->name);
1684         packet_send();
1685         packet_write_wait();
1686
1687         jpake_step1(pctx->grp,
1688             &pctx->client_id, &pctx->client_id_len,
1689             &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2,
1690             &x1_proof, &x1_proof_len,
1691             &x2_proof, &x2_proof_len);
1692
1693         JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__));
1694
1695         packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1);
1696         packet_put_string(pctx->client_id, pctx->client_id_len);
1697         packet_put_bignum2(pctx->g_x1);
1698         packet_put_bignum2(pctx->g_x2);
1699         packet_put_string(x1_proof, x1_proof_len);
1700         packet_put_string(x2_proof, x2_proof_len);
1701         packet_send();
1702
1703         bzero(x1_proof, x1_proof_len);
1704         bzero(x2_proof, x2_proof_len);
1705         xfree(x1_proof);
1706         xfree(x2_proof);
1707
1708         /* Expect step 1 packet from peer */
1709         dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1,
1710             input_userauth_jpake_server_step1);
1711
1712         return 1;
1713 }
1714
1715 void
1716 userauth_jpake_cleanup(Authctxt *authctxt)
1717 {
1718         debug3("%s: clean up", __func__);
1719         if (authctxt->methoddata != NULL) {
1720                 jpake_free(authctxt->methoddata);
1721                 authctxt->methoddata = NULL;
1722         }
1723 }
1724 #endif /* JPAKE */
1725
1726 /* find auth method */
1727
1728 /*
1729  * given auth method name, if configurable options permit this method fill
1730  * in auth_ident field and return true, otherwise return false.
1731  */
1732 static int
1733 authmethod_is_enabled(Authmethod *method)
1734 {
1735         if (method == NULL)
1736                 return 0;
1737         /* return false if options indicate this method is disabled */
1738         if  (method->enabled == NULL || *method->enabled == 0)
1739                 return 0;
1740         /* return false if batch mode is enabled but method needs interactive mode */
1741         if  (method->batch_flag != NULL && *method->batch_flag != 0)
1742                 return 0;
1743         return 1;
1744 }
1745
1746 static Authmethod *
1747 authmethod_lookup(const char *name)
1748 {
1749         Authmethod *method = NULL;
1750         if (name != NULL)
1751                 for (method = authmethods; method->name != NULL; method++)
1752                         if (strcmp(name, method->name) == 0)
1753                                 return method;
1754         debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1755         return NULL;
1756 }
1757
1758 /* XXX internal state */
1759 static Authmethod *current = NULL;
1760 static char *supported = NULL;
1761 static char *preferred = NULL;
1762
1763 /*
1764  * Given the authentication method list sent by the server, return the
1765  * next method we should try.  If the server initially sends a nil list,
1766  * use a built-in default list.
1767  */
1768 static Authmethod *
1769 authmethod_get(char *authlist)
1770 {
1771         char *name = NULL;
1772         u_int next;
1773
1774         /* Use a suitable default if we're passed a nil list.  */
1775         if (authlist == NULL || strlen(authlist) == 0)
1776                 authlist = options.preferred_authentications;
1777
1778         if (supported == NULL || strcmp(authlist, supported) != 0) {
1779                 debug3("start over, passed a different list %s", authlist);
1780                 if (supported != NULL)
1781                         xfree(supported);
1782                 supported = xstrdup(authlist);
1783                 preferred = options.preferred_authentications;
1784                 debug3("preferred %s", preferred);
1785                 current = NULL;
1786         } else if (current != NULL && authmethod_is_enabled(current))
1787                 return current;
1788
1789         for (;;) {
1790                 if ((name = match_list(preferred, supported, &next)) == NULL) {
1791                         debug("No more authentication methods to try.");
1792                         current = NULL;
1793                         return NULL;
1794                 }
1795                 preferred += next;
1796                 debug3("authmethod_lookup %s", name);
1797                 debug3("remaining preferred: %s", preferred);
1798                 if ((current = authmethod_lookup(name)) != NULL &&
1799                     authmethod_is_enabled(current)) {
1800                         debug3("authmethod_is_enabled %s", name);
1801                         debug("Next authentication method: %s", name);
1802                         return current;
1803                 }
1804         }
1805 }
1806
1807 static char *
1808 authmethods_get(void)
1809 {
1810         Authmethod *method = NULL;
1811         Buffer b;
1812         char *list;
1813
1814         buffer_init(&b);
1815         for (method = authmethods; method->name != NULL; method++) {
1816                 if (authmethod_is_enabled(method)) {
1817                         if (buffer_len(&b) > 0)
1818                                 buffer_append(&b, ",", 1);
1819                         buffer_append(&b, method->name, strlen(method->name));
1820                 }
1821         }
1822         buffer_append(&b, "\0", 1);
1823         list = xstrdup(buffer_ptr(&b));
1824         buffer_free(&b);
1825         return list;
1826 }
1827