Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2000 Markus Friedl. All rights reserved. |
| 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * 1. Redistributions of source code must retain the above copyright |
| 8 | * notice, this list of conditions and the following disclaimer. |
| 9 | * 2. Redistributions in binary form must reproduce the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer in the |
| 11 | * documentation and/or other materials provided with the distribution. |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 12 | * |
| 13 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 14 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 15 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 16 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 17 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 18 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 19 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 20 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 22 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 23 | */ |
| 24 | |
| 25 | #include "includes.h" |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 26 | RCSID("$OpenBSD: sshconnect2.c,v 1.20 2000/09/21 11:25:07 markus Exp $"); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 27 | |
| 28 | #include <openssl/bn.h> |
| 29 | #include <openssl/rsa.h> |
| 30 | #include <openssl/dsa.h> |
| 31 | #include <openssl/md5.h> |
| 32 | #include <openssl/dh.h> |
| 33 | #include <openssl/hmac.h> |
| 34 | |
| 35 | #include "ssh.h" |
| 36 | #include "xmalloc.h" |
| 37 | #include "rsa.h" |
| 38 | #include "buffer.h" |
| 39 | #include "packet.h" |
| 40 | #include "cipher.h" |
| 41 | #include "uidswap.h" |
| 42 | #include "compat.h" |
| 43 | #include "readconf.h" |
| 44 | #include "bufaux.h" |
| 45 | #include "ssh2.h" |
| 46 | #include "kex.h" |
| 47 | #include "myproposal.h" |
| 48 | #include "key.h" |
| 49 | #include "dsa.h" |
| 50 | #include "sshconnect.h" |
| 51 | #include "authfile.h" |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 52 | #include "dispatch.h" |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 53 | #include "authfd.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 54 | |
| 55 | /* import */ |
| 56 | extern char *client_version_string; |
| 57 | extern char *server_version_string; |
| 58 | extern Options options; |
| 59 | |
| 60 | /* |
| 61 | * SSH2 key exchange |
| 62 | */ |
| 63 | |
| 64 | unsigned char *session_id2 = NULL; |
| 65 | int session_id2_len = 0; |
| 66 | |
| 67 | void |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 68 | ssh_kex_dh(Kex *kex, char *host, struct sockaddr *hostaddr, |
| 69 | Buffer *client_kexinit, Buffer *server_kexinit) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 70 | { |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 71 | #ifdef DEBUG_KEXDH |
| 72 | int i; |
| 73 | #endif |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 74 | int plen, dlen; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 75 | unsigned int klen, kout; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 76 | char *signature = NULL; |
| 77 | unsigned int slen; |
| 78 | char *server_host_key_blob = NULL; |
| 79 | Key *server_host_key; |
| 80 | unsigned int sbloblen; |
| 81 | DH *dh; |
| 82 | BIGNUM *dh_server_pub = 0; |
| 83 | BIGNUM *shared_secret = 0; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 84 | unsigned char *kbuf; |
| 85 | unsigned char *hash; |
| 86 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 87 | debug("Sending SSH2_MSG_KEXDH_INIT."); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 88 | /* generate and send 'e', client DH public key */ |
| 89 | dh = dh_new_group1(); |
| 90 | packet_start(SSH2_MSG_KEXDH_INIT); |
| 91 | packet_put_bignum2(dh->pub_key); |
| 92 | packet_send(); |
| 93 | packet_write_wait(); |
| 94 | |
| 95 | #ifdef DEBUG_KEXDH |
| 96 | fprintf(stderr, "\np= "); |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 97 | BN_print_fp(stderr, dh->p); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 98 | fprintf(stderr, "\ng= "); |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 99 | BN_print_fp(stderr, dh->g); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 100 | fprintf(stderr, "\npub= "); |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 101 | BN_print_fp(stderr, dh->pub_key); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 102 | fprintf(stderr, "\n"); |
| 103 | DHparams_print_fp(stderr, dh); |
| 104 | #endif |
| 105 | |
| 106 | debug("Wait SSH2_MSG_KEXDH_REPLY."); |
| 107 | |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 108 | packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 109 | |
| 110 | debug("Got SSH2_MSG_KEXDH_REPLY."); |
| 111 | |
| 112 | /* key, cert */ |
| 113 | server_host_key_blob = packet_get_string(&sbloblen); |
| 114 | server_host_key = dsa_key_from_blob(server_host_key_blob, sbloblen); |
| 115 | if (server_host_key == NULL) |
| 116 | fatal("cannot decode server_host_key_blob"); |
| 117 | |
| 118 | check_host_key(host, hostaddr, server_host_key, |
| 119 | options.user_hostfile2, options.system_hostfile2); |
| 120 | |
| 121 | /* DH paramter f, server public DH key */ |
| 122 | dh_server_pub = BN_new(); |
| 123 | if (dh_server_pub == NULL) |
| 124 | fatal("dh_server_pub == NULL"); |
| 125 | packet_get_bignum2(dh_server_pub, &dlen); |
| 126 | |
| 127 | #ifdef DEBUG_KEXDH |
| 128 | fprintf(stderr, "\ndh_server_pub= "); |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 129 | BN_print_fp(stderr, dh_server_pub); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 130 | fprintf(stderr, "\n"); |
| 131 | debug("bits %d", BN_num_bits(dh_server_pub)); |
| 132 | #endif |
| 133 | |
| 134 | /* signed H */ |
| 135 | signature = packet_get_string(&slen); |
| 136 | packet_done(); |
| 137 | |
| 138 | if (!dh_pub_is_valid(dh, dh_server_pub)) |
| 139 | packet_disconnect("bad server public DH value"); |
| 140 | |
| 141 | klen = DH_size(dh); |
| 142 | kbuf = xmalloc(klen); |
| 143 | kout = DH_compute_key(kbuf, dh_server_pub, dh); |
| 144 | #ifdef DEBUG_KEXDH |
| 145 | debug("shared secret: len %d/%d", klen, kout); |
| 146 | fprintf(stderr, "shared secret == "); |
| 147 | for (i = 0; i< kout; i++) |
| 148 | fprintf(stderr, "%02x", (kbuf[i])&0xff); |
| 149 | fprintf(stderr, "\n"); |
| 150 | #endif |
| 151 | shared_secret = BN_new(); |
| 152 | |
| 153 | BN_bin2bn(kbuf, kout, shared_secret); |
| 154 | memset(kbuf, 0, klen); |
| 155 | xfree(kbuf); |
| 156 | |
| 157 | /* calc and verify H */ |
| 158 | hash = kex_hash( |
| 159 | client_version_string, |
| 160 | server_version_string, |
| 161 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), |
| 162 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), |
| 163 | server_host_key_blob, sbloblen, |
| 164 | dh->pub_key, |
| 165 | dh_server_pub, |
| 166 | shared_secret |
| 167 | ); |
| 168 | xfree(server_host_key_blob); |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 169 | DH_free(dh); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 170 | #ifdef DEBUG_KEXDH |
| 171 | fprintf(stderr, "hash == "); |
| 172 | for (i = 0; i< 20; i++) |
| 173 | fprintf(stderr, "%02x", (hash[i])&0xff); |
| 174 | fprintf(stderr, "\n"); |
| 175 | #endif |
| 176 | if (dsa_verify(server_host_key, (unsigned char *)signature, slen, hash, 20) != 1) |
| 177 | fatal("dsa_verify failed for server_host_key"); |
| 178 | key_free(server_host_key); |
| 179 | |
| 180 | kex_derive_keys(kex, hash, shared_secret); |
| 181 | packet_set_kex(kex); |
| 182 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 183 | /* save session id */ |
| 184 | session_id2_len = 20; |
| 185 | session_id2 = xmalloc(session_id2_len); |
| 186 | memcpy(session_id2, hash, session_id2_len); |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 187 | } |
| 188 | |
| 189 | void |
| 190 | ssh_kex2(char *host, struct sockaddr *hostaddr) |
| 191 | { |
| 192 | int i, plen; |
| 193 | Kex *kex; |
| 194 | Buffer *client_kexinit, *server_kexinit; |
| 195 | char *sprop[PROPOSAL_MAX]; |
| 196 | |
| 197 | if (options.ciphers != NULL) { |
| 198 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
| 199 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
| 200 | } else if (options.cipher == SSH_CIPHER_3DES) { |
| 201 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
| 202 | myproposal[PROPOSAL_ENC_ALGS_STOC] = |
| 203 | (char *) cipher_name(SSH_CIPHER_3DES_CBC); |
| 204 | } else if (options.cipher == SSH_CIPHER_BLOWFISH) { |
| 205 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
| 206 | myproposal[PROPOSAL_ENC_ALGS_STOC] = |
| 207 | (char *) cipher_name(SSH_CIPHER_BLOWFISH_CBC); |
| 208 | } |
| 209 | if (options.compression) { |
| 210 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = "zlib"; |
| 211 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; |
| 212 | } else { |
| 213 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = "none"; |
| 214 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
| 215 | } |
| 216 | |
| 217 | /* buffers with raw kexinit messages */ |
| 218 | server_kexinit = xmalloc(sizeof(*server_kexinit)); |
| 219 | buffer_init(server_kexinit); |
| 220 | client_kexinit = kex_init(myproposal); |
| 221 | |
| 222 | /* algorithm negotiation */ |
| 223 | kex_exchange_kexinit(client_kexinit, server_kexinit, sprop); |
| 224 | kex = kex_choose_conf(myproposal, sprop, 0); |
| 225 | for (i = 0; i < PROPOSAL_MAX; i++) |
| 226 | xfree(sprop[i]); |
| 227 | |
| 228 | /* server authentication and session key agreement */ |
| 229 | ssh_kex_dh(kex, host, hostaddr, client_kexinit, server_kexinit); |
| 230 | |
| 231 | buffer_free(client_kexinit); |
| 232 | buffer_free(server_kexinit); |
| 233 | xfree(client_kexinit); |
| 234 | xfree(server_kexinit); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 235 | |
| 236 | debug("Wait SSH2_MSG_NEWKEYS."); |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 237 | packet_read_expect(&plen, SSH2_MSG_NEWKEYS); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 238 | packet_done(); |
| 239 | debug("GOT SSH2_MSG_NEWKEYS."); |
| 240 | |
| 241 | debug("send SSH2_MSG_NEWKEYS."); |
| 242 | packet_start(SSH2_MSG_NEWKEYS); |
| 243 | packet_send(); |
| 244 | packet_write_wait(); |
| 245 | debug("done: send SSH2_MSG_NEWKEYS."); |
| 246 | |
| 247 | #ifdef DEBUG_KEXDH |
| 248 | /* send 1st encrypted/maced/compressed message */ |
| 249 | packet_start(SSH2_MSG_IGNORE); |
| 250 | packet_put_cstring("markus"); |
| 251 | packet_send(); |
| 252 | packet_write_wait(); |
| 253 | #endif |
| 254 | debug("done: KEX2."); |
| 255 | } |
Damien Miller | b1715dc | 2000-05-30 13:44:51 +1000 | [diff] [blame] | 256 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 257 | /* |
| 258 | * Authenticate user |
| 259 | */ |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 260 | |
| 261 | typedef struct Authctxt Authctxt; |
| 262 | typedef struct Authmethod Authmethod; |
| 263 | |
| 264 | typedef int sign_cb_fn( |
| 265 | Authctxt *authctxt, Key *key, |
| 266 | unsigned char **sigp, int *lenp, unsigned char *data, int datalen); |
| 267 | |
| 268 | struct Authctxt { |
| 269 | const char *server_user; |
| 270 | const char *host; |
| 271 | const char *service; |
| 272 | AuthenticationConnection *agent; |
| 273 | int success; |
| 274 | Authmethod *method; |
| 275 | }; |
| 276 | struct Authmethod { |
| 277 | char *name; /* string to compare against server's list */ |
| 278 | int (*userauth)(Authctxt *authctxt); |
| 279 | int *enabled; /* flag in option struct that enables method */ |
| 280 | int *batch_flag; /* flag in option struct that disables method */ |
| 281 | }; |
| 282 | |
| 283 | void input_userauth_success(int type, int plen, void *ctxt); |
| 284 | void input_userauth_failure(int type, int plen, void *ctxt); |
| 285 | void input_userauth_error(int type, int plen, void *ctxt); |
| 286 | int userauth_pubkey(Authctxt *authctxt); |
| 287 | int userauth_passwd(Authctxt *authctxt); |
| 288 | |
| 289 | void authmethod_clear(); |
| 290 | Authmethod *authmethod_get(char *auth_list); |
| 291 | |
| 292 | Authmethod authmethods[] = { |
| 293 | {"publickey", |
| 294 | userauth_pubkey, |
| 295 | &options.dsa_authentication, |
| 296 | NULL}, |
| 297 | {"password", |
| 298 | userauth_passwd, |
| 299 | &options.password_authentication, |
| 300 | &options.batch_mode}, |
| 301 | {NULL, NULL, NULL, NULL} |
| 302 | }; |
| 303 | |
| 304 | void |
| 305 | ssh_userauth2(const char *server_user, char *host) |
| 306 | { |
| 307 | Authctxt authctxt; |
| 308 | int type; |
| 309 | int plen; |
| 310 | |
| 311 | debug("send SSH2_MSG_SERVICE_REQUEST"); |
| 312 | packet_start(SSH2_MSG_SERVICE_REQUEST); |
| 313 | packet_put_cstring("ssh-userauth"); |
| 314 | packet_send(); |
| 315 | packet_write_wait(); |
| 316 | type = packet_read(&plen); |
| 317 | if (type != SSH2_MSG_SERVICE_ACCEPT) { |
| 318 | fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); |
| 319 | } |
| 320 | if (packet_remaining() > 0) { |
| 321 | char *reply = packet_get_string(&plen); |
| 322 | debug("service_accept: %s", reply); |
| 323 | xfree(reply); |
| 324 | packet_done(); |
| 325 | } else { |
| 326 | debug("buggy server: service_accept w/o service"); |
| 327 | } |
| 328 | packet_done(); |
| 329 | debug("got SSH2_MSG_SERVICE_ACCEPT"); |
| 330 | |
| 331 | /* setup authentication context */ |
| 332 | authctxt.agent = ssh_get_authentication_connection(); |
| 333 | authctxt.server_user = server_user; |
| 334 | authctxt.host = host; |
| 335 | authctxt.service = "ssh-connection"; /* service name */ |
| 336 | authctxt.success = 0; |
| 337 | authctxt.method = NULL; |
| 338 | |
| 339 | /* initial userauth request */ |
| 340 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| 341 | packet_put_cstring(authctxt.server_user); |
| 342 | packet_put_cstring(authctxt.service); |
| 343 | packet_put_cstring("none"); |
| 344 | packet_send(); |
| 345 | packet_write_wait(); |
| 346 | |
| 347 | authmethod_clear(); |
| 348 | |
| 349 | dispatch_init(&input_userauth_error); |
| 350 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); |
| 351 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); |
| 352 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
| 353 | |
| 354 | if (authctxt.agent != NULL) |
| 355 | ssh_close_authentication_connection(authctxt.agent); |
| 356 | |
| 357 | debug("ssh-userauth2 successfull"); |
| 358 | } |
| 359 | void |
| 360 | input_userauth_error(int type, int plen, void *ctxt) |
| 361 | { |
| 362 | fatal("input_userauth_error: bad message during authentication"); |
| 363 | } |
| 364 | void |
| 365 | input_userauth_success(int type, int plen, void *ctxt) |
| 366 | { |
| 367 | Authctxt *authctxt = ctxt; |
| 368 | if (authctxt == NULL) |
| 369 | fatal("input_userauth_success: no authentication context"); |
| 370 | authctxt->success = 1; /* break out */ |
| 371 | } |
| 372 | void |
| 373 | input_userauth_failure(int type, int plen, void *ctxt) |
| 374 | { |
| 375 | Authmethod *method = NULL; |
| 376 | Authctxt *authctxt = ctxt; |
| 377 | char *authlist = NULL; |
| 378 | int partial; |
| 379 | int dlen; |
| 380 | |
| 381 | if (authctxt == NULL) |
| 382 | fatal("input_userauth_failure: no authentication context"); |
| 383 | |
| 384 | authlist = packet_get_string(&dlen); |
| 385 | partial = packet_get_char(); |
| 386 | packet_done(); |
| 387 | |
| 388 | if (partial != 0) |
| 389 | debug("partial success"); |
| 390 | debug("authentications that can continue: %s", authlist); |
| 391 | |
| 392 | for (;;) { |
| 393 | /* try old method or get next method */ |
| 394 | method = authmethod_get(authlist); |
| 395 | if (method == NULL) |
| 396 | fatal("Unable to find an authentication method"); |
| 397 | if (method->userauth(authctxt) != 0) { |
| 398 | debug2("we sent a packet, wait for reply"); |
| 399 | break; |
| 400 | } else { |
| 401 | debug2("we did not send a packet, disable method"); |
| 402 | method->enabled = NULL; |
| 403 | } |
| 404 | } |
| 405 | xfree(authlist); |
| 406 | } |
| 407 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 408 | int |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 409 | userauth_passwd(Authctxt *authctxt) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 410 | { |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 411 | static int attempt = 0; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 412 | char prompt[80]; |
| 413 | char *password; |
| 414 | |
Damien Miller | d3a1857 | 2000-06-07 19:55:44 +1000 | [diff] [blame] | 415 | if (attempt++ >= options.number_of_password_prompts) |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 416 | return 0; |
| 417 | |
Damien Miller | d3a1857 | 2000-06-07 19:55:44 +1000 | [diff] [blame] | 418 | if(attempt != 1) |
| 419 | error("Permission denied, please try again."); |
| 420 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 421 | snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ", |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 422 | authctxt->server_user, authctxt->host); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 423 | password = read_passphrase(prompt, 0); |
| 424 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 425 | packet_put_cstring(authctxt->server_user); |
| 426 | packet_put_cstring(authctxt->service); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 427 | packet_put_cstring("password"); |
| 428 | packet_put_char(0); |
| 429 | packet_put_cstring(password); |
| 430 | memset(password, 0, strlen(password)); |
| 431 | xfree(password); |
| 432 | packet_send(); |
| 433 | packet_write_wait(); |
| 434 | return 1; |
| 435 | } |
| 436 | |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 437 | int |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 438 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 439 | { |
| 440 | Buffer b; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 441 | unsigned char *blob, *signature; |
| 442 | int bloblen, slen; |
Damien Miller | 6536c7d | 2000-06-22 21:32:31 +1000 | [diff] [blame] | 443 | int skip = 0; |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 444 | int ret = -1; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 445 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 446 | dsa_make_key_blob(k, &blob, &bloblen); |
| 447 | |
| 448 | /* data to be signed */ |
| 449 | buffer_init(&b); |
Damien Miller | 6536c7d | 2000-06-22 21:32:31 +1000 | [diff] [blame] | 450 | if (datafellows & SSH_COMPAT_SESSIONID_ENCODING) { |
| 451 | buffer_put_string(&b, session_id2, session_id2_len); |
| 452 | skip = buffer_len(&b); |
| 453 | } else { |
| 454 | buffer_append(&b, session_id2, session_id2_len); |
| 455 | skip = session_id2_len; |
| 456 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 457 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 458 | buffer_put_cstring(&b, authctxt->server_user); |
Damien Miller | 30c3d42 | 2000-05-09 11:02:59 +1000 | [diff] [blame] | 459 | buffer_put_cstring(&b, |
| 460 | datafellows & SSH_BUG_PUBKEYAUTH ? |
| 461 | "ssh-userauth" : |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 462 | authctxt->service); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 463 | buffer_put_cstring(&b, "publickey"); |
| 464 | buffer_put_char(&b, 1); |
| 465 | buffer_put_cstring(&b, KEX_DSS); |
| 466 | buffer_put_string(&b, blob, bloblen); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 467 | |
| 468 | /* generate signature */ |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 469 | ret = (*sign_callback)(authctxt, k, &signature, &slen, buffer_ptr(&b), buffer_len(&b)); |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 470 | if (ret == -1) { |
| 471 | xfree(blob); |
| 472 | buffer_free(&b); |
| 473 | return 0; |
| 474 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 475 | #ifdef DEBUG_DSS |
| 476 | buffer_dump(&b); |
| 477 | #endif |
Damien Miller | 30c3d42 | 2000-05-09 11:02:59 +1000 | [diff] [blame] | 478 | if (datafellows & SSH_BUG_PUBKEYAUTH) { |
Damien Miller | 30c3d42 | 2000-05-09 11:02:59 +1000 | [diff] [blame] | 479 | buffer_clear(&b); |
| 480 | buffer_append(&b, session_id2, session_id2_len); |
| 481 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 482 | buffer_put_cstring(&b, authctxt->server_user); |
| 483 | buffer_put_cstring(&b, authctxt->service); |
Damien Miller | 30c3d42 | 2000-05-09 11:02:59 +1000 | [diff] [blame] | 484 | buffer_put_cstring(&b, "publickey"); |
| 485 | buffer_put_char(&b, 1); |
| 486 | buffer_put_cstring(&b, KEX_DSS); |
| 487 | buffer_put_string(&b, blob, bloblen); |
| 488 | } |
| 489 | xfree(blob); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 490 | /* append signature */ |
| 491 | buffer_put_string(&b, signature, slen); |
| 492 | xfree(signature); |
| 493 | |
| 494 | /* skip session id and packet type */ |
Damien Miller | 6536c7d | 2000-06-22 21:32:31 +1000 | [diff] [blame] | 495 | if (buffer_len(&b) < skip + 1) |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 496 | fatal("userauth_pubkey: internal error"); |
Damien Miller | 6536c7d | 2000-06-22 21:32:31 +1000 | [diff] [blame] | 497 | buffer_consume(&b, skip + 1); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 498 | |
| 499 | /* put remaining data from buffer into packet */ |
| 500 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
| 501 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); |
| 502 | buffer_free(&b); |
| 503 | |
| 504 | /* send */ |
| 505 | packet_send(); |
| 506 | packet_write_wait(); |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 507 | |
| 508 | return 1; |
Damien Miller | 994cf14 | 2000-07-21 10:19:44 +1000 | [diff] [blame] | 509 | } |
| 510 | |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 511 | /* sign callback */ |
| 512 | int dsa_sign_cb(Authctxt *authctxt, Key *key, unsigned char **sigp, int *lenp, |
| 513 | unsigned char *data, int datalen) |
| 514 | { |
| 515 | return dsa_sign(key, sigp, lenp, data, datalen); |
| 516 | } |
| 517 | |
Damien Miller | 994cf14 | 2000-07-21 10:19:44 +1000 | [diff] [blame] | 518 | int |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 519 | userauth_pubkey_identity(Authctxt *authctxt, char *filename) |
Damien Miller | 994cf14 | 2000-07-21 10:19:44 +1000 | [diff] [blame] | 520 | { |
| 521 | Key *k; |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 522 | int i, ret, try_next; |
Damien Miller | 994cf14 | 2000-07-21 10:19:44 +1000 | [diff] [blame] | 523 | struct stat st; |
| 524 | |
| 525 | if (stat(filename, &st) != 0) { |
| 526 | debug("key does not exist: %s", filename); |
| 527 | return 0; |
| 528 | } |
| 529 | debug("try pubkey: %s", filename); |
| 530 | |
| 531 | k = key_new(KEY_DSA); |
| 532 | if (!load_private_key(filename, "", k, NULL)) { |
| 533 | int success = 0; |
| 534 | char *passphrase; |
| 535 | char prompt[300]; |
| 536 | snprintf(prompt, sizeof prompt, |
| 537 | "Enter passphrase for DSA key '%.100s': ", |
| 538 | filename); |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 539 | for (i = 0; i < options.number_of_password_prompts; i++) { |
| 540 | passphrase = read_passphrase(prompt, 0); |
| 541 | if (strcmp(passphrase, "") != 0) { |
| 542 | success = load_private_key(filename, passphrase, k, NULL); |
| 543 | try_next = 0; |
| 544 | } else { |
| 545 | debug2("no passphrase given, try next key"); |
| 546 | try_next = 1; |
| 547 | } |
| 548 | memset(passphrase, 0, strlen(passphrase)); |
| 549 | xfree(passphrase); |
| 550 | if (success || try_next) |
| 551 | break; |
| 552 | debug2("bad passphrase given, try again..."); |
| 553 | } |
Damien Miller | 994cf14 | 2000-07-21 10:19:44 +1000 | [diff] [blame] | 554 | if (!success) { |
| 555 | key_free(k); |
| 556 | return 0; |
| 557 | } |
| 558 | } |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 559 | ret = sign_and_send_pubkey(authctxt, k, dsa_sign_cb); |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 560 | key_free(k); |
| 561 | return ret; |
| 562 | } |
| 563 | |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 564 | /* sign callback */ |
| 565 | int agent_sign_cb(Authctxt *authctxt, Key *key, unsigned char **sigp, int *lenp, |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 566 | unsigned char *data, int datalen) |
| 567 | { |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 568 | return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 569 | } |
| 570 | |
| 571 | int |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 572 | userauth_pubkey_agent(Authctxt *authctxt) |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 573 | { |
| 574 | static int called = 0; |
| 575 | char *comment; |
| 576 | Key *k; |
| 577 | int ret; |
| 578 | |
| 579 | if (called == 0) { |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 580 | k = ssh_get_first_identity(authctxt->agent, &comment, 2); |
| 581 | called = 1; |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 582 | } else { |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 583 | k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 584 | } |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 585 | if (k == NULL) { |
| 586 | debug2("no more DSA keys from agent"); |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 587 | return 0; |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 588 | } |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 589 | debug("trying DSA agent key %s", comment); |
| 590 | xfree(comment); |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 591 | ret = sign_and_send_pubkey(authctxt, k, agent_sign_cb); |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 592 | key_free(k); |
| 593 | return ret; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 594 | } |
| 595 | |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 596 | int |
| 597 | userauth_pubkey(Authctxt *authctxt) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 598 | { |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 599 | static int idx = 0; |
| 600 | int sent = 0; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 601 | |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 602 | if (authctxt->agent != NULL) |
| 603 | sent = userauth_pubkey_agent(authctxt); |
| 604 | while (sent == 0 && idx < options.num_identity_files2) |
| 605 | sent = userauth_pubkey_identity(authctxt, options.identity_files2[idx++]); |
| 606 | return sent; |
| 607 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 608 | |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 609 | |
| 610 | /* find auth method */ |
| 611 | |
| 612 | #define DELIM "," |
| 613 | |
| 614 | static char *def_authlist = "publickey,password"; |
| 615 | static char *authlist_current = NULL; /* clean copy used for comparison */ |
| 616 | static char *authname_current = NULL; /* last used auth method */ |
| 617 | static char *authlist_working = NULL; /* copy that gets modified by strtok_r() */ |
| 618 | static char *authlist_state = NULL; /* state variable for strtok_r() */ |
| 619 | |
| 620 | /* |
| 621 | * Before starting to use a new authentication method list sent by the |
| 622 | * server, reset internal variables. This should also be called when |
| 623 | * finished processing server list to free resources. |
| 624 | */ |
| 625 | void |
| 626 | authmethod_clear() |
| 627 | { |
| 628 | if (authlist_current != NULL) { |
| 629 | xfree(authlist_current); |
| 630 | authlist_current = NULL; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 631 | } |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 632 | if (authlist_working != NULL) { |
| 633 | xfree(authlist_working); |
| 634 | authlist_working = NULL; |
| 635 | } |
| 636 | if (authname_current != NULL) { |
| 637 | xfree(authname_current); |
| 638 | authlist_state = NULL; |
| 639 | } |
| 640 | if (authlist_state != NULL) |
| 641 | authlist_state = NULL; |
| 642 | return; |
| 643 | } |
| 644 | |
| 645 | /* |
| 646 | * given auth method name, if configurable options permit this method fill |
| 647 | * in auth_ident field and return true, otherwise return false. |
| 648 | */ |
| 649 | int |
| 650 | authmethod_is_enabled(Authmethod *method) |
| 651 | { |
| 652 | if (method == NULL) |
| 653 | return 0; |
| 654 | /* return false if options indicate this method is disabled */ |
| 655 | if (method->enabled == NULL || *method->enabled == 0) |
| 656 | return 0; |
| 657 | /* return false if batch mode is enabled but method needs interactive mode */ |
| 658 | if (method->batch_flag != NULL && *method->batch_flag != 0) |
| 659 | return 0; |
| 660 | return 1; |
| 661 | } |
| 662 | |
| 663 | Authmethod * |
| 664 | authmethod_lookup(const char *name) |
| 665 | { |
| 666 | Authmethod *method = NULL; |
| 667 | if (name != NULL) |
| 668 | for (method = authmethods; method->name != NULL; method++) |
| 669 | if (strcmp(name, method->name) == 0) |
| 670 | return method; |
| 671 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); |
| 672 | return NULL; |
| 673 | } |
| 674 | |
| 675 | /* |
| 676 | * Given the authentication method list sent by the server, return the |
| 677 | * next method we should try. If the server initially sends a nil list, |
| 678 | * use a built-in default list. If the server sends a nil list after |
| 679 | * previously sending a valid list, continue using the list originally |
| 680 | * sent. |
| 681 | */ |
| 682 | |
| 683 | Authmethod * |
| 684 | authmethod_get(char *authlist) |
| 685 | { |
| 686 | char *name = NULL; |
| 687 | Authmethod *method = NULL; |
| 688 | |
| 689 | /* Use a suitable default if we're passed a nil list. */ |
| 690 | if (authlist == NULL || strlen(authlist) == 0) |
| 691 | authlist = def_authlist; |
| 692 | |
| 693 | if (authlist_current == NULL || strcmp(authlist, authlist_current) != 0) { |
| 694 | /* start over if passed a different list */ |
| 695 | authmethod_clear(); |
| 696 | authlist_current = xstrdup(authlist); |
| 697 | authlist_working = xstrdup(authlist); |
| 698 | name = strtok_r(authlist_working, DELIM, &authlist_state); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 699 | } else { |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 700 | /* |
| 701 | * try to use previously used authentication method |
| 702 | * or continue to use previously passed list |
| 703 | */ |
| 704 | name = (authname_current != NULL) ? |
| 705 | authname_current : strtok_r(NULL, DELIM, &authlist_state); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 706 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 707 | |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 708 | while (name != NULL) { |
| 709 | method = authmethod_lookup(name); |
| 710 | if (method != NULL && authmethod_is_enabled(method)) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 711 | break; |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 712 | name = strtok_r(NULL, DELIM, &authlist_state); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 713 | } |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame^] | 714 | |
| 715 | if (authname_current != NULL) |
| 716 | xfree(authname_current); |
| 717 | |
| 718 | if (name != NULL) { |
| 719 | debug("next auth method to try is %s", name); |
| 720 | authname_current = xstrdup(name); |
| 721 | return method; |
| 722 | } else { |
| 723 | debug("no more auth methods to try"); |
| 724 | authname_current = NULL; |
| 725 | return NULL; |
| 726 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 727 | } |