| 1 | /* $OpenBSD: sshconnect2.c,v 1.166 2008/07/17 08:48:00 djm Exp $ */ |
| 2 | /* |
| 3 | * Copyright (c) 2000 Markus Friedl. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * |
| 14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 15 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 16 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 17 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 18 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 19 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 20 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 21 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 23 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 24 | */ |
| 25 | |
| 26 | #include "includes.h" |
| 27 | |
| 28 | #include <sys/types.h> |
| 29 | #include <sys/socket.h> |
| 30 | #include <sys/wait.h> |
| 31 | #include <sys/stat.h> |
| 32 | |
| 33 | #include <errno.h> |
| 34 | #include <netdb.h> |
| 35 | #include <pwd.h> |
| 36 | #include <signal.h> |
| 37 | #include <stdarg.h> |
| 38 | #include <stdio.h> |
| 39 | #include <string.h> |
| 40 | #include <unistd.h> |
| 41 | #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) |
| 42 | #include <vis.h> |
| 43 | #endif |
| 44 | |
| 45 | #include "openbsd-compat/sys-queue.h" |
| 46 | |
| 47 | #include "xmalloc.h" |
| 48 | #include "ssh.h" |
| 49 | #include "ssh2.h" |
| 50 | #include "buffer.h" |
| 51 | #include "packet.h" |
| 52 | #include "compat.h" |
| 53 | #include "cipher.h" |
| 54 | #include "key.h" |
| 55 | #include "kex.h" |
| 56 | #include "myproposal.h" |
| 57 | #include "sshconnect.h" |
| 58 | #include "authfile.h" |
| 59 | #include "dh.h" |
| 60 | #include "authfd.h" |
| 61 | #include "log.h" |
| 62 | #include "readconf.h" |
| 63 | #include "misc.h" |
| 64 | #include "match.h" |
| 65 | #include "dispatch.h" |
| 66 | #include "canohost.h" |
| 67 | #include "msg.h" |
| 68 | #include "pathnames.h" |
| 69 | #include "uidswap.h" |
| 70 | |
| 71 | #ifdef GSSAPI |
| 72 | #include "ssh-gss.h" |
| 73 | #endif |
| 74 | |
| 75 | /* import */ |
| 76 | extern char *client_version_string; |
| 77 | extern char *server_version_string; |
| 78 | extern Options options; |
| 79 | |
| 80 | /* |
| 81 | * SSH2 key exchange |
| 82 | */ |
| 83 | |
| 84 | u_char *session_id2 = NULL; |
| 85 | u_int session_id2_len = 0; |
| 86 | |
| 87 | char *xxx_host; |
| 88 | struct sockaddr *xxx_hostaddr; |
| 89 | |
| 90 | Kex *xxx_kex = NULL; |
| 91 | |
| 92 | static int |
| 93 | verify_host_key_callback(Key *hostkey) |
| 94 | { |
| 95 | if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) |
| 96 | fatal("Host key verification failed."); |
| 97 | return 0; |
| 98 | } |
| 99 | |
| 100 | void |
| 101 | ssh_kex2(char *host, struct sockaddr *hostaddr) |
| 102 | { |
| 103 | Kex *kex; |
| 104 | |
| 105 | xxx_host = host; |
| 106 | xxx_hostaddr = hostaddr; |
| 107 | |
| 108 | if (options.ciphers == (char *)-1) { |
| 109 | logit("No valid ciphers for protocol version 2 given, using defaults."); |
| 110 | options.ciphers = NULL; |
| 111 | } |
| 112 | if (options.ciphers != NULL) { |
| 113 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
| 114 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
| 115 | } |
| 116 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
| 117 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); |
| 118 | myproposal[PROPOSAL_ENC_ALGS_STOC] = |
| 119 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); |
| 120 | if (options.compression) { |
| 121 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
| 122 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; |
| 123 | } else { |
| 124 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
| 125 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; |
| 126 | } |
| 127 | if (options.macs != NULL) { |
| 128 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = |
| 129 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; |
| 130 | } |
| 131 | if (options.hostkeyalgorithms != NULL) |
| 132 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = |
| 133 | options.hostkeyalgorithms; |
| 134 | |
| 135 | if (options.rekey_limit) |
| 136 | packet_set_rekey_limit((u_int32_t)options.rekey_limit); |
| 137 | |
| 138 | /* start key exchange */ |
| 139 | kex = kex_setup(myproposal); |
| 140 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; |
| 141 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; |
| 142 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; |
| 143 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; |
| 144 | kex->client_version_string=client_version_string; |
| 145 | kex->server_version_string=server_version_string; |
| 146 | kex->verify_host_key=&verify_host_key_callback; |
| 147 | |
| 148 | xxx_kex = kex; |
| 149 | |
| 150 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
| 151 | |
| 152 | session_id2 = kex->session_id; |
| 153 | session_id2_len = kex->session_id_len; |
| 154 | |
| 155 | #ifdef DEBUG_KEXDH |
| 156 | /* send 1st encrypted/maced/compressed message */ |
| 157 | packet_start(SSH2_MSG_IGNORE); |
| 158 | packet_put_cstring("markus"); |
| 159 | packet_send(); |
| 160 | packet_write_wait(); |
| 161 | #endif |
| 162 | } |
| 163 | |
| 164 | /* |
| 165 | * Authenticate user |
| 166 | */ |
| 167 | |
| 168 | typedef struct Authctxt Authctxt; |
| 169 | typedef struct Authmethod Authmethod; |
| 170 | typedef struct identity Identity; |
| 171 | typedef struct idlist Idlist; |
| 172 | |
| 173 | struct identity { |
| 174 | TAILQ_ENTRY(identity) next; |
| 175 | AuthenticationConnection *ac; /* set if agent supports key */ |
| 176 | Key *key; /* public/private key */ |
| 177 | char *filename; /* comment for agent-only keys */ |
| 178 | int tried; |
| 179 | int isprivate; /* key points to the private key */ |
| 180 | }; |
| 181 | TAILQ_HEAD(idlist, identity); |
| 182 | |
| 183 | struct Authctxt { |
| 184 | const char *server_user; |
| 185 | const char *local_user; |
| 186 | const char *host; |
| 187 | const char *service; |
| 188 | Authmethod *method; |
| 189 | int success; |
| 190 | char *authlist; |
| 191 | /* pubkey */ |
| 192 | Idlist keys; |
| 193 | AuthenticationConnection *agent; |
| 194 | /* hostbased */ |
| 195 | Sensitive *sensitive; |
| 196 | /* kbd-interactive */ |
| 197 | int info_req_seen; |
| 198 | /* generic */ |
| 199 | void *methoddata; |
| 200 | }; |
| 201 | struct Authmethod { |
| 202 | char *name; /* string to compare against server's list */ |
| 203 | int (*userauth)(Authctxt *authctxt); |
| 204 | int *enabled; /* flag in option struct that enables method */ |
| 205 | int *batch_flag; /* flag in option struct that disables method */ |
| 206 | }; |
| 207 | |
| 208 | void input_userauth_success(int, u_int32_t, void *); |
| 209 | void input_userauth_failure(int, u_int32_t, void *); |
| 210 | void input_userauth_banner(int, u_int32_t, void *); |
| 211 | void input_userauth_error(int, u_int32_t, void *); |
| 212 | void input_userauth_info_req(int, u_int32_t, void *); |
| 213 | void input_userauth_pk_ok(int, u_int32_t, void *); |
| 214 | void input_userauth_passwd_changereq(int, u_int32_t, void *); |
| 215 | |
| 216 | int userauth_none(Authctxt *); |
| 217 | int userauth_pubkey(Authctxt *); |
| 218 | int userauth_passwd(Authctxt *); |
| 219 | int userauth_kbdint(Authctxt *); |
| 220 | int userauth_hostbased(Authctxt *); |
| 221 | int userauth_kerberos(Authctxt *); |
| 222 | |
| 223 | #ifdef GSSAPI |
| 224 | int userauth_gssapi(Authctxt *authctxt); |
| 225 | void input_gssapi_response(int type, u_int32_t, void *); |
| 226 | void input_gssapi_token(int type, u_int32_t, void *); |
| 227 | void input_gssapi_hash(int type, u_int32_t, void *); |
| 228 | void input_gssapi_error(int, u_int32_t, void *); |
| 229 | void input_gssapi_errtok(int, u_int32_t, void *); |
| 230 | #endif |
| 231 | |
| 232 | void userauth(Authctxt *, char *); |
| 233 | |
| 234 | static int sign_and_send_pubkey(Authctxt *, Identity *); |
| 235 | static void pubkey_prepare(Authctxt *); |
| 236 | static void pubkey_cleanup(Authctxt *); |
| 237 | static Key *load_identity_file(char *); |
| 238 | |
| 239 | static Authmethod *authmethod_get(char *authlist); |
| 240 | static Authmethod *authmethod_lookup(const char *name); |
| 241 | static char *authmethods_get(void); |
| 242 | |
| 243 | Authmethod authmethods[] = { |
| 244 | #ifdef GSSAPI |
| 245 | {"gssapi-with-mic", |
| 246 | userauth_gssapi, |
| 247 | &options.gss_authentication, |
| 248 | NULL}, |
| 249 | #endif |
| 250 | {"hostbased", |
| 251 | userauth_hostbased, |
| 252 | &options.hostbased_authentication, |
| 253 | NULL}, |
| 254 | {"publickey", |
| 255 | userauth_pubkey, |
| 256 | &options.pubkey_authentication, |
| 257 | NULL}, |
| 258 | {"keyboard-interactive", |
| 259 | userauth_kbdint, |
| 260 | &options.kbd_interactive_authentication, |
| 261 | &options.batch_mode}, |
| 262 | {"password", |
| 263 | userauth_passwd, |
| 264 | &options.password_authentication, |
| 265 | &options.batch_mode}, |
| 266 | {"none", |
| 267 | userauth_none, |
| 268 | NULL, |
| 269 | NULL}, |
| 270 | {NULL, NULL, NULL, NULL} |
| 271 | }; |
| 272 | |
| 273 | void |
| 274 | ssh_userauth2(const char *local_user, const char *server_user, char *host, |
| 275 | Sensitive *sensitive) |
| 276 | { |
| 277 | Authctxt authctxt; |
| 278 | int type; |
| 279 | |
| 280 | if (options.challenge_response_authentication) |
| 281 | options.kbd_interactive_authentication = 1; |
| 282 | |
| 283 | packet_start(SSH2_MSG_SERVICE_REQUEST); |
| 284 | packet_put_cstring("ssh-userauth"); |
| 285 | packet_send(); |
| 286 | debug("SSH2_MSG_SERVICE_REQUEST sent"); |
| 287 | packet_write_wait(); |
| 288 | type = packet_read(); |
| 289 | if (type != SSH2_MSG_SERVICE_ACCEPT) |
| 290 | fatal("Server denied authentication request: %d", type); |
| 291 | if (packet_remaining() > 0) { |
| 292 | char *reply = packet_get_string(NULL); |
| 293 | debug2("service_accept: %s", reply); |
| 294 | xfree(reply); |
| 295 | } else { |
| 296 | debug2("buggy server: service_accept w/o service"); |
| 297 | } |
| 298 | packet_check_eom(); |
| 299 | debug("SSH2_MSG_SERVICE_ACCEPT received"); |
| 300 | |
| 301 | if (options.preferred_authentications == NULL) |
| 302 | options.preferred_authentications = authmethods_get(); |
| 303 | |
| 304 | /* setup authentication context */ |
| 305 | memset(&authctxt, 0, sizeof(authctxt)); |
| 306 | pubkey_prepare(&authctxt); |
| 307 | authctxt.server_user = server_user; |
| 308 | authctxt.local_user = local_user; |
| 309 | authctxt.host = host; |
| 310 | authctxt.service = "ssh-connection"; /* service name */ |
| 311 | authctxt.success = 0; |
| 312 | authctxt.method = authmethod_lookup("none"); |
| 313 | authctxt.authlist = NULL; |
| 314 | authctxt.methoddata = NULL; |
| 315 | authctxt.sensitive = sensitive; |
| 316 | authctxt.info_req_seen = 0; |
| 317 | if (authctxt.method == NULL) |
| 318 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); |
| 319 | |
| 320 | /* initial userauth request */ |
| 321 | userauth_none(&authctxt); |
| 322 | |
| 323 | dispatch_init(&input_userauth_error); |
| 324 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); |
| 325 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); |
| 326 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
| 327 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
| 328 | |
| 329 | pubkey_cleanup(&authctxt); |
| 330 | dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); |
| 331 | |
| 332 | debug("Authentication succeeded (%s).", authctxt.method->name); |
| 333 | } |
| 334 | |
| 335 | void |
| 336 | userauth(Authctxt *authctxt, char *authlist) |
| 337 | { |
| 338 | if (authctxt->methoddata) { |
| 339 | xfree(authctxt->methoddata); |
| 340 | authctxt->methoddata = NULL; |
| 341 | } |
| 342 | if (authlist == NULL) { |
| 343 | authlist = authctxt->authlist; |
| 344 | } else { |
| 345 | if (authctxt->authlist) |
| 346 | xfree(authctxt->authlist); |
| 347 | authctxt->authlist = authlist; |
| 348 | } |
| 349 | for (;;) { |
| 350 | Authmethod *method = authmethod_get(authlist); |
| 351 | if (method == NULL) |
| 352 | fatal("Permission denied (%s).", authlist); |
| 353 | authctxt->method = method; |
| 354 | |
| 355 | /* reset the per method handler */ |
| 356 | dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, |
| 357 | SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); |
| 358 | |
| 359 | /* and try new method */ |
| 360 | if (method->userauth(authctxt) != 0) { |
| 361 | debug2("we sent a %s packet, wait for reply", method->name); |
| 362 | break; |
| 363 | } else { |
| 364 | debug2("we did not send a packet, disable method"); |
| 365 | method->enabled = NULL; |
| 366 | } |
| 367 | } |
| 368 | } |
| 369 | |
| 370 | void |
| 371 | input_userauth_error(int type, u_int32_t seq, void *ctxt) |
| 372 | { |
| 373 | fatal("input_userauth_error: bad message during authentication: " |
| 374 | "type %d", type); |
| 375 | } |
| 376 | |
| 377 | void |
| 378 | input_userauth_banner(int type, u_int32_t seq, void *ctxt) |
| 379 | { |
| 380 | char *msg, *raw, *lang; |
| 381 | u_int len; |
| 382 | |
| 383 | debug3("input_userauth_banner"); |
| 384 | raw = packet_get_string(&len); |
| 385 | lang = packet_get_string(NULL); |
| 386 | if (options.log_level >= SYSLOG_LEVEL_INFO) { |
| 387 | if (len > 65536) |
| 388 | len = 65536; |
| 389 | msg = xmalloc(len * 4); /* max expansion from strnvis() */ |
| 390 | strnvis(msg, raw, len * 4, VIS_SAFE|VIS_OCTAL); |
| 391 | fprintf(stderr, "%s", msg); |
| 392 | xfree(msg); |
| 393 | } |
| 394 | xfree(raw); |
| 395 | xfree(lang); |
| 396 | } |
| 397 | |
| 398 | void |
| 399 | input_userauth_success(int type, u_int32_t seq, void *ctxt) |
| 400 | { |
| 401 | Authctxt *authctxt = ctxt; |
| 402 | if (authctxt == NULL) |
| 403 | fatal("input_userauth_success: no authentication context"); |
| 404 | if (authctxt->authlist) { |
| 405 | xfree(authctxt->authlist); |
| 406 | authctxt->authlist = NULL; |
| 407 | } |
| 408 | if (authctxt->methoddata) { |
| 409 | xfree(authctxt->methoddata); |
| 410 | authctxt->methoddata = NULL; |
| 411 | } |
| 412 | authctxt->success = 1; /* break out */ |
| 413 | } |
| 414 | |
| 415 | void |
| 416 | input_userauth_failure(int type, u_int32_t seq, void *ctxt) |
| 417 | { |
| 418 | Authctxt *authctxt = ctxt; |
| 419 | char *authlist = NULL; |
| 420 | int partial; |
| 421 | |
| 422 | if (authctxt == NULL) |
| 423 | fatal("input_userauth_failure: no authentication context"); |
| 424 | |
| 425 | authlist = packet_get_string(NULL); |
| 426 | partial = packet_get_char(); |
| 427 | packet_check_eom(); |
| 428 | |
| 429 | if (partial != 0) |
| 430 | logit("Authenticated with partial success."); |
| 431 | debug("Authentications that can continue: %s", authlist); |
| 432 | |
| 433 | userauth(authctxt, authlist); |
| 434 | } |
| 435 | void |
| 436 | input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) |
| 437 | { |
| 438 | Authctxt *authctxt = ctxt; |
| 439 | Key *key = NULL; |
| 440 | Identity *id = NULL; |
| 441 | Buffer b; |
| 442 | int pktype, sent = 0; |
| 443 | u_int alen, blen; |
| 444 | char *pkalg, *fp; |
| 445 | u_char *pkblob; |
| 446 | |
| 447 | if (authctxt == NULL) |
| 448 | fatal("input_userauth_pk_ok: no authentication context"); |
| 449 | if (datafellows & SSH_BUG_PKOK) { |
| 450 | /* this is similar to SSH_BUG_PKAUTH */ |
| 451 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); |
| 452 | pkblob = packet_get_string(&blen); |
| 453 | buffer_init(&b); |
| 454 | buffer_append(&b, pkblob, blen); |
| 455 | pkalg = buffer_get_string(&b, &alen); |
| 456 | buffer_free(&b); |
| 457 | } else { |
| 458 | pkalg = packet_get_string(&alen); |
| 459 | pkblob = packet_get_string(&blen); |
| 460 | } |
| 461 | packet_check_eom(); |
| 462 | |
| 463 | debug("Server accepts key: pkalg %s blen %u", pkalg, blen); |
| 464 | |
| 465 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { |
| 466 | debug("unknown pkalg %s", pkalg); |
| 467 | goto done; |
| 468 | } |
| 469 | if ((key = key_from_blob(pkblob, blen)) == NULL) { |
| 470 | debug("no key from blob. pkalg %s", pkalg); |
| 471 | goto done; |
| 472 | } |
| 473 | if (key->type != pktype) { |
| 474 | error("input_userauth_pk_ok: type mismatch " |
| 475 | "for decoded key (received %d, expected %d)", |
| 476 | key->type, pktype); |
| 477 | goto done; |
| 478 | } |
| 479 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
| 480 | debug2("input_userauth_pk_ok: fp %s", fp); |
| 481 | xfree(fp); |
| 482 | |
| 483 | /* |
| 484 | * search keys in the reverse order, because last candidate has been |
| 485 | * moved to the end of the queue. this also avoids confusion by |
| 486 | * duplicate keys |
| 487 | */ |
| 488 | TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { |
| 489 | if (key_equal(key, id->key)) { |
| 490 | sent = sign_and_send_pubkey(authctxt, id); |
| 491 | break; |
| 492 | } |
| 493 | } |
| 494 | done: |
| 495 | if (key != NULL) |
| 496 | key_free(key); |
| 497 | xfree(pkalg); |
| 498 | xfree(pkblob); |
| 499 | |
| 500 | /* try another method if we did not send a packet */ |
| 501 | if (sent == 0) |
| 502 | userauth(authctxt, NULL); |
| 503 | } |
| 504 | |
| 505 | #ifdef GSSAPI |
| 506 | int |
| 507 | userauth_gssapi(Authctxt *authctxt) |
| 508 | { |
| 509 | Gssctxt *gssctxt = NULL; |
| 510 | static gss_OID_set gss_supported = NULL; |
| 511 | static u_int mech = 0; |
| 512 | OM_uint32 min; |
| 513 | int ok = 0; |
| 514 | |
| 515 | /* Try one GSSAPI method at a time, rather than sending them all at |
| 516 | * once. */ |
| 517 | |
| 518 | if (gss_supported == NULL) |
| 519 | gss_indicate_mechs(&min, &gss_supported); |
| 520 | |
| 521 | /* Check to see if the mechanism is usable before we offer it */ |
| 522 | while (mech < gss_supported->count && !ok) { |
| 523 | /* My DER encoding requires length<128 */ |
| 524 | if (gss_supported->elements[mech].length < 128 && |
| 525 | ssh_gssapi_check_mechanism(&gssctxt, |
| 526 | &gss_supported->elements[mech], authctxt->host)) { |
| 527 | ok = 1; /* Mechanism works */ |
| 528 | } else { |
| 529 | mech++; |
| 530 | } |
| 531 | } |
| 532 | |
| 533 | if (!ok) |
| 534 | return 0; |
| 535 | |
| 536 | authctxt->methoddata=(void *)gssctxt; |
| 537 | |
| 538 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| 539 | packet_put_cstring(authctxt->server_user); |
| 540 | packet_put_cstring(authctxt->service); |
| 541 | packet_put_cstring(authctxt->method->name); |
| 542 | |
| 543 | packet_put_int(1); |
| 544 | |
| 545 | packet_put_int((gss_supported->elements[mech].length) + 2); |
| 546 | packet_put_char(SSH_GSS_OIDTYPE); |
| 547 | packet_put_char(gss_supported->elements[mech].length); |
| 548 | packet_put_raw(gss_supported->elements[mech].elements, |
| 549 | gss_supported->elements[mech].length); |
| 550 | |
| 551 | packet_send(); |
| 552 | |
| 553 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); |
| 554 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); |
| 555 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); |
| 556 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); |
| 557 | |
| 558 | mech++; /* Move along to next candidate */ |
| 559 | |
| 560 | return 1; |
| 561 | } |
| 562 | |
| 563 | static OM_uint32 |
| 564 | process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) |
| 565 | { |
| 566 | Authctxt *authctxt = ctxt; |
| 567 | Gssctxt *gssctxt = authctxt->methoddata; |
| 568 | gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; |
| 569 | gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; |
| 570 | gss_buffer_desc gssbuf; |
| 571 | OM_uint32 status, ms, flags; |
| 572 | Buffer b; |
| 573 | |
| 574 | status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, |
| 575 | recv_tok, &send_tok, &flags); |
| 576 | |
| 577 | if (send_tok.length > 0) { |
| 578 | if (GSS_ERROR(status)) |
| 579 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); |
| 580 | else |
| 581 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); |
| 582 | |
| 583 | packet_put_string(send_tok.value, send_tok.length); |
| 584 | packet_send(); |
| 585 | gss_release_buffer(&ms, &send_tok); |
| 586 | } |
| 587 | |
| 588 | if (status == GSS_S_COMPLETE) { |
| 589 | /* send either complete or MIC, depending on mechanism */ |
| 590 | if (!(flags & GSS_C_INTEG_FLAG)) { |
| 591 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); |
| 592 | packet_send(); |
| 593 | } else { |
| 594 | ssh_gssapi_buildmic(&b, authctxt->server_user, |
| 595 | authctxt->service, "gssapi-with-mic"); |
| 596 | |
| 597 | gssbuf.value = buffer_ptr(&b); |
| 598 | gssbuf.length = buffer_len(&b); |
| 599 | |
| 600 | status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); |
| 601 | |
| 602 | if (!GSS_ERROR(status)) { |
| 603 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); |
| 604 | packet_put_string(mic.value, mic.length); |
| 605 | |
| 606 | packet_send(); |
| 607 | } |
| 608 | |
| 609 | buffer_free(&b); |
| 610 | gss_release_buffer(&ms, &mic); |
| 611 | } |
| 612 | } |
| 613 | |
| 614 | return status; |
| 615 | } |
| 616 | |
| 617 | void |
| 618 | input_gssapi_response(int type, u_int32_t plen, void *ctxt) |
| 619 | { |
| 620 | Authctxt *authctxt = ctxt; |
| 621 | Gssctxt *gssctxt; |
| 622 | int oidlen; |
| 623 | char *oidv; |
| 624 | |
| 625 | if (authctxt == NULL) |
| 626 | fatal("input_gssapi_response: no authentication context"); |
| 627 | gssctxt = authctxt->methoddata; |
| 628 | |
| 629 | /* Setup our OID */ |
| 630 | oidv = packet_get_string(&oidlen); |
| 631 | |
| 632 | if (oidlen <= 2 || |
| 633 | oidv[0] != SSH_GSS_OIDTYPE || |
| 634 | oidv[1] != oidlen - 2) { |
| 635 | xfree(oidv); |
| 636 | debug("Badly encoded mechanism OID received"); |
| 637 | userauth(authctxt, NULL); |
| 638 | return; |
| 639 | } |
| 640 | |
| 641 | if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) |
| 642 | fatal("Server returned different OID than expected"); |
| 643 | |
| 644 | packet_check_eom(); |
| 645 | |
| 646 | xfree(oidv); |
| 647 | |
| 648 | if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { |
| 649 | /* Start again with next method on list */ |
| 650 | debug("Trying to start again"); |
| 651 | userauth(authctxt, NULL); |
| 652 | return; |
| 653 | } |
| 654 | } |
| 655 | |
| 656 | void |
| 657 | input_gssapi_token(int type, u_int32_t plen, void *ctxt) |
| 658 | { |
| 659 | Authctxt *authctxt = ctxt; |
| 660 | gss_buffer_desc recv_tok; |
| 661 | OM_uint32 status; |
| 662 | u_int slen; |
| 663 | |
| 664 | if (authctxt == NULL) |
| 665 | fatal("input_gssapi_response: no authentication context"); |
| 666 | |
| 667 | recv_tok.value = packet_get_string(&slen); |
| 668 | recv_tok.length = slen; /* safe typecast */ |
| 669 | |
| 670 | packet_check_eom(); |
| 671 | |
| 672 | status = process_gssapi_token(ctxt, &recv_tok); |
| 673 | |
| 674 | xfree(recv_tok.value); |
| 675 | |
| 676 | if (GSS_ERROR(status)) { |
| 677 | /* Start again with the next method in the list */ |
| 678 | userauth(authctxt, NULL); |
| 679 | return; |
| 680 | } |
| 681 | } |
| 682 | |
| 683 | void |
| 684 | input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) |
| 685 | { |
| 686 | Authctxt *authctxt = ctxt; |
| 687 | Gssctxt *gssctxt; |
| 688 | gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; |
| 689 | gss_buffer_desc recv_tok; |
| 690 | OM_uint32 status, ms; |
| 691 | u_int len; |
| 692 | |
| 693 | if (authctxt == NULL) |
| 694 | fatal("input_gssapi_response: no authentication context"); |
| 695 | gssctxt = authctxt->methoddata; |
| 696 | |
| 697 | recv_tok.value = packet_get_string(&len); |
| 698 | recv_tok.length = len; |
| 699 | |
| 700 | packet_check_eom(); |
| 701 | |
| 702 | /* Stick it into GSSAPI and see what it says */ |
| 703 | status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, |
| 704 | &recv_tok, &send_tok, NULL); |
| 705 | |
| 706 | xfree(recv_tok.value); |
| 707 | gss_release_buffer(&ms, &send_tok); |
| 708 | |
| 709 | /* Server will be returning a failed packet after this one */ |
| 710 | } |
| 711 | |
| 712 | void |
| 713 | input_gssapi_error(int type, u_int32_t plen, void *ctxt) |
| 714 | { |
| 715 | OM_uint32 maj, min; |
| 716 | char *msg; |
| 717 | char *lang; |
| 718 | |
| 719 | maj=packet_get_int(); |
| 720 | min=packet_get_int(); |
| 721 | msg=packet_get_string(NULL); |
| 722 | lang=packet_get_string(NULL); |
| 723 | |
| 724 | packet_check_eom(); |
| 725 | |
| 726 | debug("Server GSSAPI Error:\n%s", msg); |
| 727 | xfree(msg); |
| 728 | xfree(lang); |
| 729 | } |
| 730 | #endif /* GSSAPI */ |
| 731 | |
| 732 | int |
| 733 | userauth_none(Authctxt *authctxt) |
| 734 | { |
| 735 | /* initial userauth request */ |
| 736 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| 737 | packet_put_cstring(authctxt->server_user); |
| 738 | packet_put_cstring(authctxt->service); |
| 739 | packet_put_cstring(authctxt->method->name); |
| 740 | packet_send(); |
| 741 | return 1; |
| 742 | } |
| 743 | |
| 744 | int |
| 745 | userauth_passwd(Authctxt *authctxt) |
| 746 | { |
| 747 | static int attempt = 0; |
| 748 | char prompt[150]; |
| 749 | char *password; |
| 750 | |
| 751 | if (attempt++ >= options.number_of_password_prompts) |
| 752 | return 0; |
| 753 | |
| 754 | if (attempt != 1) |
| 755 | error("Permission denied, please try again."); |
| 756 | |
| 757 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
| 758 | authctxt->server_user, authctxt->host); |
| 759 | password = read_passphrase(prompt, 0); |
| 760 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| 761 | packet_put_cstring(authctxt->server_user); |
| 762 | packet_put_cstring(authctxt->service); |
| 763 | packet_put_cstring(authctxt->method->name); |
| 764 | packet_put_char(0); |
| 765 | packet_put_cstring(password); |
| 766 | memset(password, 0, strlen(password)); |
| 767 | xfree(password); |
| 768 | packet_add_padding(64); |
| 769 | packet_send(); |
| 770 | |
| 771 | dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, |
| 772 | &input_userauth_passwd_changereq); |
| 773 | |
| 774 | return 1; |
| 775 | } |
| 776 | /* |
| 777 | * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST |
| 778 | */ |
| 779 | void |
| 780 | input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) |
| 781 | { |
| 782 | Authctxt *authctxt = ctxt; |
| 783 | char *info, *lang, *password = NULL, *retype = NULL; |
| 784 | char prompt[150]; |
| 785 | |
| 786 | debug2("input_userauth_passwd_changereq"); |
| 787 | |
| 788 | if (authctxt == NULL) |
| 789 | fatal("input_userauth_passwd_changereq: " |
| 790 | "no authentication context"); |
| 791 | |
| 792 | info = packet_get_string(NULL); |
| 793 | lang = packet_get_string(NULL); |
| 794 | if (strlen(info) > 0) |
| 795 | logit("%s", info); |
| 796 | xfree(info); |
| 797 | xfree(lang); |
| 798 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| 799 | packet_put_cstring(authctxt->server_user); |
| 800 | packet_put_cstring(authctxt->service); |
| 801 | packet_put_cstring(authctxt->method->name); |
| 802 | packet_put_char(1); /* additional info */ |
| 803 | snprintf(prompt, sizeof(prompt), |
| 804 | "Enter %.30s@%.128s's old password: ", |
| 805 | authctxt->server_user, authctxt->host); |
| 806 | password = read_passphrase(prompt, 0); |
| 807 | packet_put_cstring(password); |
| 808 | memset(password, 0, strlen(password)); |
| 809 | xfree(password); |
| 810 | password = NULL; |
| 811 | while (password == NULL) { |
| 812 | snprintf(prompt, sizeof(prompt), |
| 813 | "Enter %.30s@%.128s's new password: ", |
| 814 | authctxt->server_user, authctxt->host); |
| 815 | password = read_passphrase(prompt, RP_ALLOW_EOF); |
| 816 | if (password == NULL) { |
| 817 | /* bail out */ |
| 818 | return; |
| 819 | } |
| 820 | snprintf(prompt, sizeof(prompt), |
| 821 | "Retype %.30s@%.128s's new password: ", |
| 822 | authctxt->server_user, authctxt->host); |
| 823 | retype = read_passphrase(prompt, 0); |
| 824 | if (strcmp(password, retype) != 0) { |
| 825 | memset(password, 0, strlen(password)); |
| 826 | xfree(password); |
| 827 | logit("Mismatch; try again, EOF to quit."); |
| 828 | password = NULL; |
| 829 | } |
| 830 | memset(retype, 0, strlen(retype)); |
| 831 | xfree(retype); |
| 832 | } |
| 833 | packet_put_cstring(password); |
| 834 | memset(password, 0, strlen(password)); |
| 835 | xfree(password); |
| 836 | packet_add_padding(64); |
| 837 | packet_send(); |
| 838 | |
| 839 | dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, |
| 840 | &input_userauth_passwd_changereq); |
| 841 | } |
| 842 | |
| 843 | static int |
| 844 | identity_sign(Identity *id, u_char **sigp, u_int *lenp, |
| 845 | u_char *data, u_int datalen) |
| 846 | { |
| 847 | Key *prv; |
| 848 | int ret; |
| 849 | |
| 850 | /* the agent supports this key */ |
| 851 | if (id->ac) |
| 852 | return (ssh_agent_sign(id->ac, id->key, sigp, lenp, |
| 853 | data, datalen)); |
| 854 | /* |
| 855 | * we have already loaded the private key or |
| 856 | * the private key is stored in external hardware |
| 857 | */ |
| 858 | if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) |
| 859 | return (key_sign(id->key, sigp, lenp, data, datalen)); |
| 860 | /* load the private key from the file */ |
| 861 | if ((prv = load_identity_file(id->filename)) == NULL) |
| 862 | return (-1); |
| 863 | ret = key_sign(prv, sigp, lenp, data, datalen); |
| 864 | key_free(prv); |
| 865 | return (ret); |
| 866 | } |
| 867 | |
| 868 | static int |
| 869 | sign_and_send_pubkey(Authctxt *authctxt, Identity *id) |
| 870 | { |
| 871 | Buffer b; |
| 872 | u_char *blob, *signature; |
| 873 | u_int bloblen, slen; |
| 874 | u_int skip = 0; |
| 875 | int ret = -1; |
| 876 | int have_sig = 1; |
| 877 | |
| 878 | debug3("sign_and_send_pubkey"); |
| 879 | |
| 880 | if (key_to_blob(id->key, &blob, &bloblen) == 0) { |
| 881 | /* we cannot handle this key */ |
| 882 | debug3("sign_and_send_pubkey: cannot handle key"); |
| 883 | return 0; |
| 884 | } |
| 885 | /* data to be signed */ |
| 886 | buffer_init(&b); |
| 887 | if (datafellows & SSH_OLD_SESSIONID) { |
| 888 | buffer_append(&b, session_id2, session_id2_len); |
| 889 | skip = session_id2_len; |
| 890 | } else { |
| 891 | buffer_put_string(&b, session_id2, session_id2_len); |
| 892 | skip = buffer_len(&b); |
| 893 | } |
| 894 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
| 895 | buffer_put_cstring(&b, authctxt->server_user); |
| 896 | buffer_put_cstring(&b, |
| 897 | datafellows & SSH_BUG_PKSERVICE ? |
| 898 | "ssh-userauth" : |
| 899 | authctxt->service); |
| 900 | if (datafellows & SSH_BUG_PKAUTH) { |
| 901 | buffer_put_char(&b, have_sig); |
| 902 | } else { |
| 903 | buffer_put_cstring(&b, authctxt->method->name); |
| 904 | buffer_put_char(&b, have_sig); |
| 905 | buffer_put_cstring(&b, key_ssh_name(id->key)); |
| 906 | } |
| 907 | buffer_put_string(&b, blob, bloblen); |
| 908 | |
| 909 | /* generate signature */ |
| 910 | ret = identity_sign(id, &signature, &slen, |
| 911 | buffer_ptr(&b), buffer_len(&b)); |
| 912 | if (ret == -1) { |
| 913 | xfree(blob); |
| 914 | buffer_free(&b); |
| 915 | return 0; |
| 916 | } |
| 917 | #ifdef DEBUG_PK |
| 918 | buffer_dump(&b); |
| 919 | #endif |
| 920 | if (datafellows & SSH_BUG_PKSERVICE) { |
| 921 | buffer_clear(&b); |
| 922 | buffer_append(&b, session_id2, session_id2_len); |
| 923 | skip = session_id2_len; |
| 924 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
| 925 | buffer_put_cstring(&b, authctxt->server_user); |
| 926 | buffer_put_cstring(&b, authctxt->service); |
| 927 | buffer_put_cstring(&b, authctxt->method->name); |
| 928 | buffer_put_char(&b, have_sig); |
| 929 | if (!(datafellows & SSH_BUG_PKAUTH)) |
| 930 | buffer_put_cstring(&b, key_ssh_name(id->key)); |
| 931 | buffer_put_string(&b, blob, bloblen); |
| 932 | } |
| 933 | xfree(blob); |
| 934 | |
| 935 | /* append signature */ |
| 936 | buffer_put_string(&b, signature, slen); |
| 937 | xfree(signature); |
| 938 | |
| 939 | /* skip session id and packet type */ |
| 940 | if (buffer_len(&b) < skip + 1) |
| 941 | fatal("userauth_pubkey: internal error"); |
| 942 | buffer_consume(&b, skip + 1); |
| 943 | |
| 944 | /* put remaining data from buffer into packet */ |
| 945 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| 946 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); |
| 947 | buffer_free(&b); |
| 948 | packet_send(); |
| 949 | |
| 950 | return 1; |
| 951 | } |
| 952 | |
| 953 | static int |
| 954 | send_pubkey_test(Authctxt *authctxt, Identity *id) |
| 955 | { |
| 956 | u_char *blob; |
| 957 | u_int bloblen, have_sig = 0; |
| 958 | |
| 959 | debug3("send_pubkey_test"); |
| 960 | |
| 961 | if (key_to_blob(id->key, &blob, &bloblen) == 0) { |
| 962 | /* we cannot handle this key */ |
| 963 | debug3("send_pubkey_test: cannot handle key"); |
| 964 | return 0; |
| 965 | } |
| 966 | /* register callback for USERAUTH_PK_OK message */ |
| 967 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); |
| 968 | |
| 969 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| 970 | packet_put_cstring(authctxt->server_user); |
| 971 | packet_put_cstring(authctxt->service); |
| 972 | packet_put_cstring(authctxt->method->name); |
| 973 | packet_put_char(have_sig); |
| 974 | if (!(datafellows & SSH_BUG_PKAUTH)) |
| 975 | packet_put_cstring(key_ssh_name(id->key)); |
| 976 | packet_put_string(blob, bloblen); |
| 977 | xfree(blob); |
| 978 | packet_send(); |
| 979 | return 1; |
| 980 | } |
| 981 | |
| 982 | static Key * |
| 983 | load_identity_file(char *filename) |
| 984 | { |
| 985 | Key *private; |
| 986 | char prompt[300], *passphrase; |
| 987 | int perm_ok, quit, i; |
| 988 | struct stat st; |
| 989 | |
| 990 | if (stat(filename, &st) < 0) { |
| 991 | debug3("no such identity: %s", filename); |
| 992 | return NULL; |
| 993 | } |
| 994 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); |
| 995 | if (!perm_ok) |
| 996 | return NULL; |
| 997 | if (private == NULL) { |
| 998 | if (options.batch_mode) |
| 999 | return NULL; |
| 1000 | snprintf(prompt, sizeof prompt, |
| 1001 | "Enter passphrase for key '%.100s': ", filename); |
| 1002 | for (i = 0; i < options.number_of_password_prompts; i++) { |
| 1003 | passphrase = read_passphrase(prompt, 0); |
| 1004 | if (strcmp(passphrase, "") != 0) { |
| 1005 | private = key_load_private_type(KEY_UNSPEC, |
| 1006 | filename, passphrase, NULL, NULL); |
| 1007 | quit = 0; |
| 1008 | } else { |
| 1009 | debug2("no passphrase given, try next key"); |
| 1010 | quit = 1; |
| 1011 | } |
| 1012 | memset(passphrase, 0, strlen(passphrase)); |
| 1013 | xfree(passphrase); |
| 1014 | if (private != NULL || quit) |
| 1015 | break; |
| 1016 | debug2("bad passphrase given, try again..."); |
| 1017 | } |
| 1018 | } |
| 1019 | return private; |
| 1020 | } |
| 1021 | |
| 1022 | /* |
| 1023 | * try keys in the following order: |
| 1024 | * 1. agent keys that are found in the config file |
| 1025 | * 2. other agent keys |
| 1026 | * 3. keys that are only listed in the config file |
| 1027 | */ |
| 1028 | static void |
| 1029 | pubkey_prepare(Authctxt *authctxt) |
| 1030 | { |
| 1031 | Identity *id; |
| 1032 | Idlist agent, files, *preferred; |
| 1033 | Key *key; |
| 1034 | AuthenticationConnection *ac; |
| 1035 | char *comment; |
| 1036 | int i, found; |
| 1037 | |
| 1038 | TAILQ_INIT(&agent); /* keys from the agent */ |
| 1039 | TAILQ_INIT(&files); /* keys from the config file */ |
| 1040 | preferred = &authctxt->keys; |
| 1041 | TAILQ_INIT(preferred); /* preferred order of keys */ |
| 1042 | |
| 1043 | /* list of keys stored in the filesystem */ |
| 1044 | for (i = 0; i < options.num_identity_files; i++) { |
| 1045 | key = options.identity_keys[i]; |
| 1046 | if (key && key->type == KEY_RSA1) |
| 1047 | continue; |
| 1048 | options.identity_keys[i] = NULL; |
| 1049 | id = xcalloc(1, sizeof(*id)); |
| 1050 | id->key = key; |
| 1051 | id->filename = xstrdup(options.identity_files[i]); |
| 1052 | TAILQ_INSERT_TAIL(&files, id, next); |
| 1053 | } |
| 1054 | /* list of keys supported by the agent */ |
| 1055 | if ((ac = ssh_get_authentication_connection())) { |
| 1056 | for (key = ssh_get_first_identity(ac, &comment, 2); |
| 1057 | key != NULL; |
| 1058 | key = ssh_get_next_identity(ac, &comment, 2)) { |
| 1059 | found = 0; |
| 1060 | TAILQ_FOREACH(id, &files, next) { |
| 1061 | /* agent keys from the config file are preferred */ |
| 1062 | if (key_equal(key, id->key)) { |
| 1063 | key_free(key); |
| 1064 | xfree(comment); |
| 1065 | TAILQ_REMOVE(&files, id, next); |
| 1066 | TAILQ_INSERT_TAIL(preferred, id, next); |
| 1067 | id->ac = ac; |
| 1068 | found = 1; |
| 1069 | break; |
| 1070 | } |
| 1071 | } |
| 1072 | if (!found && !options.identities_only) { |
| 1073 | id = xcalloc(1, sizeof(*id)); |
| 1074 | id->key = key; |
| 1075 | id->filename = comment; |
| 1076 | id->ac = ac; |
| 1077 | TAILQ_INSERT_TAIL(&agent, id, next); |
| 1078 | } |
| 1079 | } |
| 1080 | /* append remaining agent keys */ |
| 1081 | for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { |
| 1082 | TAILQ_REMOVE(&agent, id, next); |
| 1083 | TAILQ_INSERT_TAIL(preferred, id, next); |
| 1084 | } |
| 1085 | authctxt->agent = ac; |
| 1086 | } |
| 1087 | /* append remaining keys from the config file */ |
| 1088 | for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { |
| 1089 | TAILQ_REMOVE(&files, id, next); |
| 1090 | TAILQ_INSERT_TAIL(preferred, id, next); |
| 1091 | } |
| 1092 | TAILQ_FOREACH(id, preferred, next) { |
| 1093 | debug2("key: %s (%p)", id->filename, id->key); |
| 1094 | } |
| 1095 | } |
| 1096 | |
| 1097 | static void |
| 1098 | pubkey_cleanup(Authctxt *authctxt) |
| 1099 | { |
| 1100 | Identity *id; |
| 1101 | |
| 1102 | if (authctxt->agent != NULL) |
| 1103 | ssh_close_authentication_connection(authctxt->agent); |
| 1104 | for (id = TAILQ_FIRST(&authctxt->keys); id; |
| 1105 | id = TAILQ_FIRST(&authctxt->keys)) { |
| 1106 | TAILQ_REMOVE(&authctxt->keys, id, next); |
| 1107 | if (id->key) |
| 1108 | key_free(id->key); |
| 1109 | if (id->filename) |
| 1110 | xfree(id->filename); |
| 1111 | xfree(id); |
| 1112 | } |
| 1113 | } |
| 1114 | |
| 1115 | int |
| 1116 | userauth_pubkey(Authctxt *authctxt) |
| 1117 | { |
| 1118 | Identity *id; |
| 1119 | int sent = 0; |
| 1120 | |
| 1121 | while ((id = TAILQ_FIRST(&authctxt->keys))) { |
| 1122 | if (id->tried++) |
| 1123 | return (0); |
| 1124 | /* move key to the end of the queue */ |
| 1125 | TAILQ_REMOVE(&authctxt->keys, id, next); |
| 1126 | TAILQ_INSERT_TAIL(&authctxt->keys, id, next); |
| 1127 | /* |
| 1128 | * send a test message if we have the public key. for |
| 1129 | * encrypted keys we cannot do this and have to load the |
| 1130 | * private key instead |
| 1131 | */ |
| 1132 | if (id->key && id->key->type != KEY_RSA1) { |
| 1133 | debug("Offering public key: %s", id->filename); |
| 1134 | sent = send_pubkey_test(authctxt, id); |
| 1135 | } else if (id->key == NULL) { |
| 1136 | debug("Trying private key: %s", id->filename); |
| 1137 | id->key = load_identity_file(id->filename); |
| 1138 | if (id->key != NULL) { |
| 1139 | id->isprivate = 1; |
| 1140 | sent = sign_and_send_pubkey(authctxt, id); |
| 1141 | key_free(id->key); |
| 1142 | id->key = NULL; |
| 1143 | } |
| 1144 | } |
| 1145 | if (sent) |
| 1146 | return (sent); |
| 1147 | } |
| 1148 | return (0); |
| 1149 | } |
| 1150 | |
| 1151 | /* |
| 1152 | * Send userauth request message specifying keyboard-interactive method. |
| 1153 | */ |
| 1154 | int |
| 1155 | userauth_kbdint(Authctxt *authctxt) |
| 1156 | { |
| 1157 | static int attempt = 0; |
| 1158 | |
| 1159 | if (attempt++ >= options.number_of_password_prompts) |
| 1160 | return 0; |
| 1161 | /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ |
| 1162 | if (attempt > 1 && !authctxt->info_req_seen) { |
| 1163 | debug3("userauth_kbdint: disable: no info_req_seen"); |
| 1164 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); |
| 1165 | return 0; |
| 1166 | } |
| 1167 | |
| 1168 | debug2("userauth_kbdint"); |
| 1169 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| 1170 | packet_put_cstring(authctxt->server_user); |
| 1171 | packet_put_cstring(authctxt->service); |
| 1172 | packet_put_cstring(authctxt->method->name); |
| 1173 | packet_put_cstring(""); /* lang */ |
| 1174 | packet_put_cstring(options.kbd_interactive_devices ? |
| 1175 | options.kbd_interactive_devices : ""); |
| 1176 | packet_send(); |
| 1177 | |
| 1178 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); |
| 1179 | return 1; |
| 1180 | } |
| 1181 | |
| 1182 | /* |
| 1183 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
| 1184 | */ |
| 1185 | void |
| 1186 | input_userauth_info_req(int type, u_int32_t seq, void *ctxt) |
| 1187 | { |
| 1188 | Authctxt *authctxt = ctxt; |
| 1189 | char *name, *inst, *lang, *prompt, *response; |
| 1190 | u_int num_prompts, i; |
| 1191 | int echo = 0; |
| 1192 | |
| 1193 | debug2("input_userauth_info_req"); |
| 1194 | |
| 1195 | if (authctxt == NULL) |
| 1196 | fatal("input_userauth_info_req: no authentication context"); |
| 1197 | |
| 1198 | authctxt->info_req_seen = 1; |
| 1199 | |
| 1200 | name = packet_get_string(NULL); |
| 1201 | inst = packet_get_string(NULL); |
| 1202 | lang = packet_get_string(NULL); |
| 1203 | if (strlen(name) > 0) |
| 1204 | logit("%s", name); |
| 1205 | if (strlen(inst) > 0) |
| 1206 | logit("%s", inst); |
| 1207 | xfree(name); |
| 1208 | xfree(inst); |
| 1209 | xfree(lang); |
| 1210 | |
| 1211 | num_prompts = packet_get_int(); |
| 1212 | /* |
| 1213 | * Begin to build info response packet based on prompts requested. |
| 1214 | * We commit to providing the correct number of responses, so if |
| 1215 | * further on we run into a problem that prevents this, we have to |
| 1216 | * be sure and clean this up and send a correct error response. |
| 1217 | */ |
| 1218 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); |
| 1219 | packet_put_int(num_prompts); |
| 1220 | |
| 1221 | debug2("input_userauth_info_req: num_prompts %d", num_prompts); |
| 1222 | for (i = 0; i < num_prompts; i++) { |
| 1223 | prompt = packet_get_string(NULL); |
| 1224 | echo = packet_get_char(); |
| 1225 | |
| 1226 | response = read_passphrase(prompt, echo ? RP_ECHO : 0); |
| 1227 | |
| 1228 | packet_put_cstring(response); |
| 1229 | memset(response, 0, strlen(response)); |
| 1230 | xfree(response); |
| 1231 | xfree(prompt); |
| 1232 | } |
| 1233 | packet_check_eom(); /* done with parsing incoming message. */ |
| 1234 | |
| 1235 | packet_add_padding(64); |
| 1236 | packet_send(); |
| 1237 | } |
| 1238 | |
| 1239 | static int |
| 1240 | ssh_keysign(Key *key, u_char **sigp, u_int *lenp, |
| 1241 | u_char *data, u_int datalen) |
| 1242 | { |
| 1243 | Buffer b; |
| 1244 | struct stat st; |
| 1245 | pid_t pid; |
| 1246 | int to[2], from[2], status, version = 2; |
| 1247 | |
| 1248 | debug2("ssh_keysign called"); |
| 1249 | |
| 1250 | if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { |
| 1251 | error("ssh_keysign: no installed: %s", strerror(errno)); |
| 1252 | return -1; |
| 1253 | } |
| 1254 | if (fflush(stdout) != 0) |
| 1255 | error("ssh_keysign: fflush: %s", strerror(errno)); |
| 1256 | if (pipe(to) < 0) { |
| 1257 | error("ssh_keysign: pipe: %s", strerror(errno)); |
| 1258 | return -1; |
| 1259 | } |
| 1260 | if (pipe(from) < 0) { |
| 1261 | error("ssh_keysign: pipe: %s", strerror(errno)); |
| 1262 | return -1; |
| 1263 | } |
| 1264 | if ((pid = fork()) < 0) { |
| 1265 | error("ssh_keysign: fork: %s", strerror(errno)); |
| 1266 | return -1; |
| 1267 | } |
| 1268 | if (pid == 0) { |
| 1269 | permanently_drop_suid(getuid()); |
| 1270 | close(from[0]); |
| 1271 | if (dup2(from[1], STDOUT_FILENO) < 0) |
| 1272 | fatal("ssh_keysign: dup2: %s", strerror(errno)); |
| 1273 | close(to[1]); |
| 1274 | if (dup2(to[0], STDIN_FILENO) < 0) |
| 1275 | fatal("ssh_keysign: dup2: %s", strerror(errno)); |
| 1276 | close(from[1]); |
| 1277 | close(to[0]); |
| 1278 | execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); |
| 1279 | fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, |
| 1280 | strerror(errno)); |
| 1281 | } |
| 1282 | close(from[1]); |
| 1283 | close(to[0]); |
| 1284 | |
| 1285 | buffer_init(&b); |
| 1286 | buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ |
| 1287 | buffer_put_string(&b, data, datalen); |
| 1288 | if (ssh_msg_send(to[1], version, &b) == -1) |
| 1289 | fatal("ssh_keysign: couldn't send request"); |
| 1290 | |
| 1291 | if (ssh_msg_recv(from[0], &b) < 0) { |
| 1292 | error("ssh_keysign: no reply"); |
| 1293 | buffer_free(&b); |
| 1294 | return -1; |
| 1295 | } |
| 1296 | close(from[0]); |
| 1297 | close(to[1]); |
| 1298 | |
| 1299 | while (waitpid(pid, &status, 0) < 0) |
| 1300 | if (errno != EINTR) |
| 1301 | break; |
| 1302 | |
| 1303 | if (buffer_get_char(&b) != version) { |
| 1304 | error("ssh_keysign: bad version"); |
| 1305 | buffer_free(&b); |
| 1306 | return -1; |
| 1307 | } |
| 1308 | *sigp = buffer_get_string(&b, lenp); |
| 1309 | buffer_free(&b); |
| 1310 | |
| 1311 | return 0; |
| 1312 | } |
| 1313 | |
| 1314 | int |
| 1315 | userauth_hostbased(Authctxt *authctxt) |
| 1316 | { |
| 1317 | Key *private = NULL; |
| 1318 | Sensitive *sensitive = authctxt->sensitive; |
| 1319 | Buffer b; |
| 1320 | u_char *signature, *blob; |
| 1321 | char *chost, *pkalg, *p, myname[NI_MAXHOST]; |
| 1322 | const char *service; |
| 1323 | u_int blen, slen; |
| 1324 | int ok, i, len, found = 0; |
| 1325 | |
| 1326 | /* check for a useful key */ |
| 1327 | for (i = 0; i < sensitive->nkeys; i++) { |
| 1328 | private = sensitive->keys[i]; |
| 1329 | if (private && private->type != KEY_RSA1) { |
| 1330 | found = 1; |
| 1331 | /* we take and free the key */ |
| 1332 | sensitive->keys[i] = NULL; |
| 1333 | break; |
| 1334 | } |
| 1335 | } |
| 1336 | if (!found) { |
| 1337 | debug("No more client hostkeys for hostbased authentication."); |
| 1338 | return 0; |
| 1339 | } |
| 1340 | if (key_to_blob(private, &blob, &blen) == 0) { |
| 1341 | key_free(private); |
| 1342 | return 0; |
| 1343 | } |
| 1344 | /* figure out a name for the client host */ |
| 1345 | p = NULL; |
| 1346 | if (packet_connection_is_on_socket()) |
| 1347 | p = get_local_name(packet_get_connection_in()); |
| 1348 | if (p == NULL) { |
| 1349 | if (gethostname(myname, sizeof(myname)) == -1) { |
| 1350 | verbose("userauth_hostbased: gethostname: %s", |
| 1351 | strerror(errno)); |
| 1352 | } else |
| 1353 | p = xstrdup(myname); |
| 1354 | } |
| 1355 | if (p == NULL) { |
| 1356 | error("userauth_hostbased: cannot get local ipaddr/name"); |
| 1357 | key_free(private); |
| 1358 | xfree(blob); |
| 1359 | return 0; |
| 1360 | } |
| 1361 | len = strlen(p) + 2; |
| 1362 | xasprintf(&chost, "%s.", p); |
| 1363 | debug2("userauth_hostbased: chost %s", chost); |
| 1364 | xfree(p); |
| 1365 | |
| 1366 | service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : |
| 1367 | authctxt->service; |
| 1368 | pkalg = xstrdup(key_ssh_name(private)); |
| 1369 | buffer_init(&b); |
| 1370 | /* construct data */ |
| 1371 | buffer_put_string(&b, session_id2, session_id2_len); |
| 1372 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
| 1373 | buffer_put_cstring(&b, authctxt->server_user); |
| 1374 | buffer_put_cstring(&b, service); |
| 1375 | buffer_put_cstring(&b, authctxt->method->name); |
| 1376 | buffer_put_cstring(&b, pkalg); |
| 1377 | buffer_put_string(&b, blob, blen); |
| 1378 | buffer_put_cstring(&b, chost); |
| 1379 | buffer_put_cstring(&b, authctxt->local_user); |
| 1380 | #ifdef DEBUG_PK |
| 1381 | buffer_dump(&b); |
| 1382 | #endif |
| 1383 | if (sensitive->external_keysign) |
| 1384 | ok = ssh_keysign(private, &signature, &slen, |
| 1385 | buffer_ptr(&b), buffer_len(&b)); |
| 1386 | else |
| 1387 | ok = key_sign(private, &signature, &slen, |
| 1388 | buffer_ptr(&b), buffer_len(&b)); |
| 1389 | key_free(private); |
| 1390 | buffer_free(&b); |
| 1391 | if (ok != 0) { |
| 1392 | error("key_sign failed"); |
| 1393 | xfree(chost); |
| 1394 | xfree(pkalg); |
| 1395 | xfree(blob); |
| 1396 | return 0; |
| 1397 | } |
| 1398 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| 1399 | packet_put_cstring(authctxt->server_user); |
| 1400 | packet_put_cstring(authctxt->service); |
| 1401 | packet_put_cstring(authctxt->method->name); |
| 1402 | packet_put_cstring(pkalg); |
| 1403 | packet_put_string(blob, blen); |
| 1404 | packet_put_cstring(chost); |
| 1405 | packet_put_cstring(authctxt->local_user); |
| 1406 | packet_put_string(signature, slen); |
| 1407 | memset(signature, 's', slen); |
| 1408 | xfree(signature); |
| 1409 | xfree(chost); |
| 1410 | xfree(pkalg); |
| 1411 | xfree(blob); |
| 1412 | |
| 1413 | packet_send(); |
| 1414 | return 1; |
| 1415 | } |
| 1416 | |
| 1417 | /* find auth method */ |
| 1418 | |
| 1419 | /* |
| 1420 | * given auth method name, if configurable options permit this method fill |
| 1421 | * in auth_ident field and return true, otherwise return false. |
| 1422 | */ |
| 1423 | static int |
| 1424 | authmethod_is_enabled(Authmethod *method) |
| 1425 | { |
| 1426 | if (method == NULL) |
| 1427 | return 0; |
| 1428 | /* return false if options indicate this method is disabled */ |
| 1429 | if (method->enabled == NULL || *method->enabled == 0) |
| 1430 | return 0; |
| 1431 | /* return false if batch mode is enabled but method needs interactive mode */ |
| 1432 | if (method->batch_flag != NULL && *method->batch_flag != 0) |
| 1433 | return 0; |
| 1434 | return 1; |
| 1435 | } |
| 1436 | |
| 1437 | static Authmethod * |
| 1438 | authmethod_lookup(const char *name) |
| 1439 | { |
| 1440 | Authmethod *method = NULL; |
| 1441 | if (name != NULL) |
| 1442 | for (method = authmethods; method->name != NULL; method++) |
| 1443 | if (strcmp(name, method->name) == 0) |
| 1444 | return method; |
| 1445 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); |
| 1446 | return NULL; |
| 1447 | } |
| 1448 | |
| 1449 | /* XXX internal state */ |
| 1450 | static Authmethod *current = NULL; |
| 1451 | static char *supported = NULL; |
| 1452 | static char *preferred = NULL; |
| 1453 | |
| 1454 | /* |
| 1455 | * Given the authentication method list sent by the server, return the |
| 1456 | * next method we should try. If the server initially sends a nil list, |
| 1457 | * use a built-in default list. |
| 1458 | */ |
| 1459 | static Authmethod * |
| 1460 | authmethod_get(char *authlist) |
| 1461 | { |
| 1462 | char *name = NULL; |
| 1463 | u_int next; |
| 1464 | |
| 1465 | /* Use a suitable default if we're passed a nil list. */ |
| 1466 | if (authlist == NULL || strlen(authlist) == 0) |
| 1467 | authlist = options.preferred_authentications; |
| 1468 | |
| 1469 | if (supported == NULL || strcmp(authlist, supported) != 0) { |
| 1470 | debug3("start over, passed a different list %s", authlist); |
| 1471 | if (supported != NULL) |
| 1472 | xfree(supported); |
| 1473 | supported = xstrdup(authlist); |
| 1474 | preferred = options.preferred_authentications; |
| 1475 | debug3("preferred %s", preferred); |
| 1476 | current = NULL; |
| 1477 | } else if (current != NULL && authmethod_is_enabled(current)) |
| 1478 | return current; |
| 1479 | |
| 1480 | for (;;) { |
| 1481 | if ((name = match_list(preferred, supported, &next)) == NULL) { |
| 1482 | debug("No more authentication methods to try."); |
| 1483 | current = NULL; |
| 1484 | return NULL; |
| 1485 | } |
| 1486 | preferred += next; |
| 1487 | debug3("authmethod_lookup %s", name); |
| 1488 | debug3("remaining preferred: %s", preferred); |
| 1489 | if ((current = authmethod_lookup(name)) != NULL && |
| 1490 | authmethod_is_enabled(current)) { |
| 1491 | debug3("authmethod_is_enabled %s", name); |
| 1492 | debug("Next authentication method: %s", name); |
| 1493 | return current; |
| 1494 | } |
| 1495 | } |
| 1496 | } |
| 1497 | |
| 1498 | static char * |
| 1499 | authmethods_get(void) |
| 1500 | { |
| 1501 | Authmethod *method = NULL; |
| 1502 | Buffer b; |
| 1503 | char *list; |
| 1504 | |
| 1505 | buffer_init(&b); |
| 1506 | for (method = authmethods; method->name != NULL; method++) { |
| 1507 | if (authmethod_is_enabled(method)) { |
| 1508 | if (buffer_len(&b) > 0) |
| 1509 | buffer_append(&b, ",", 1); |
| 1510 | buffer_append(&b, method->name, strlen(method->name)); |
| 1511 | } |
| 1512 | } |
| 1513 | buffer_append(&b, "\0", 1); |
| 1514 | list = xstrdup(buffer_ptr(&b)); |
| 1515 | buffer_free(&b); |
| 1516 | return list; |
| 1517 | } |