Annotation of src/usr.bin/ssh/sshconnect1.c, Revision 1.47
1.1 markus 1: /*
2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
5: * Code to connect to a remote host, and to perform the client side of the
6: * login (authentication) dialog.
7: *
1.6 deraadt 8: * As far as I am concerned, the code I have written for this software
9: * can be used freely for any purpose. Any derived versions of this
10: * software must be clearly marked as such, and if the derived work is
11: * incompatible with the protocol description in the RFC file, it must be
12: * called by a name other than "ssh" or "Secure Shell".
1.1 markus 13: */
14:
15: #include "includes.h"
1.47 ! markus 16: RCSID("$OpenBSD: sshconnect1.c,v 1.46 2001/12/28 13:57:33 markus Exp $");
1.1 markus 17:
18: #include <openssl/bn.h>
19: #include <openssl/evp.h>
20:
1.18 markus 21: #ifdef KRB4
22: #include <krb.h>
23: #endif
1.37 dugsong 24: #ifdef KRB5
25: #include <krb5.h>
26: #endif
1.18 markus 27: #ifdef AFS
28: #include <kafs.h>
1.19 markus 29: #include "radix.h"
1.18 markus 30: #endif
31:
32: #include "ssh.h"
33: #include "ssh1.h"
1.1 markus 34: #include "xmalloc.h"
35: #include "rsa.h"
36: #include "buffer.h"
37: #include "packet.h"
38: #include "mpaux.h"
39: #include "uidswap.h"
1.18 markus 40: #include "log.h"
1.1 markus 41: #include "readconf.h"
42: #include "key.h"
1.4 markus 43: #include "authfd.h"
1.1 markus 44: #include "sshconnect.h"
45: #include "authfile.h"
1.18 markus 46: #include "readpass.h"
47: #include "cipher.h"
48: #include "canohost.h"
1.37 dugsong 49: #include "auth.h"
1.1 markus 50:
51: /* Session id for the current session. */
1.13 markus 52: u_char session_id[16];
53: u_int supported_authentications = 0;
1.1 markus 54:
55: extern Options options;
56: extern char *__progname;
57:
58: /*
59: * Checks if the user has an authentication agent, and if so, tries to
60: * authenticate using the agent.
61: */
1.35 itojun 62: static int
1.24 itojun 63: try_agent_authentication(void)
1.1 markus 64: {
1.5 markus 65: int type;
1.1 markus 66: char *comment;
67: AuthenticationConnection *auth;
1.13 markus 68: u_char response[16];
69: u_int i;
1.5 markus 70: Key *key;
71: BIGNUM *challenge;
1.1 markus 72:
73: /* Get connection to the agent. */
74: auth = ssh_get_authentication_connection();
75: if (!auth)
76: return 0;
77:
1.43 markus 78: if ((challenge = BN_new()) == NULL)
79: fatal("try_agent_authentication: BN_new failed");
1.1 markus 80: /* Loop through identities served by the agent. */
1.5 markus 81: for (key = ssh_get_first_identity(auth, &comment, 1);
1.42 deraadt 82: key != NULL;
83: key = ssh_get_next_identity(auth, &comment, 1)) {
1.1 markus 84:
85: /* Try this identity. */
86: debug("Trying RSA authentication via agent with '%.100s'", comment);
87: xfree(comment);
88:
89: /* Tell the server that we are willing to authenticate using this key. */
90: packet_start(SSH_CMSG_AUTH_RSA);
1.5 markus 91: packet_put_bignum(key->rsa->n);
1.1 markus 92: packet_send();
93: packet_write_wait();
94:
95: /* Wait for server's response. */
1.47 ! markus 96: type = packet_read();
1.1 markus 97:
98: /* The server sends failure if it doesn\'t like our key or
99: does not support RSA authentication. */
100: if (type == SSH_SMSG_FAILURE) {
101: debug("Server refused our key.");
1.5 markus 102: key_free(key);
1.1 markus 103: continue;
104: }
105: /* Otherwise it should have sent a challenge. */
106: if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
107: packet_disconnect("Protocol error during RSA authentication: %d",
108: type);
109:
1.46 markus 110: packet_get_bignum(challenge);
1.45 markus 111: packet_check_eom();
1.1 markus 112:
113: debug("Received RSA challenge from server.");
114:
115: /* Ask the agent to decrypt the challenge. */
1.5 markus 116: if (!ssh_decrypt_challenge(auth, key, challenge, session_id, 1, response)) {
117: /*
118: * The agent failed to authenticate this identifier
119: * although it advertised it supports this. Just
120: * return a wrong value.
121: */
1.1 markus 122: log("Authentication agent failed to decrypt challenge.");
123: memset(response, 0, sizeof(response));
124: }
1.5 markus 125: key_free(key);
1.1 markus 126: debug("Sending response to RSA challenge.");
127:
128: /* Send the decrypted challenge back to the server. */
129: packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
130: for (i = 0; i < 16; i++)
131: packet_put_char(response[i]);
132: packet_send();
133: packet_write_wait();
134:
135: /* Wait for response from the server. */
1.47 ! markus 136: type = packet_read();
1.1 markus 137:
138: /* The server returns success if it accepted the authentication. */
139: if (type == SSH_SMSG_SUCCESS) {
1.14 markus 140: ssh_close_authentication_connection(auth);
1.5 markus 141: BN_clear_free(challenge);
1.1 markus 142: debug("RSA authentication accepted by server.");
143: return 1;
144: }
145: /* Otherwise it should return failure. */
146: if (type != SSH_SMSG_FAILURE)
147: packet_disconnect("Protocol error waiting RSA auth response: %d",
148: type);
149: }
1.14 markus 150: ssh_close_authentication_connection(auth);
1.1 markus 151: BN_clear_free(challenge);
152: debug("RSA authentication using agent refused.");
153: return 0;
154: }
155:
156: /*
157: * Computes the proper response to a RSA challenge, and sends the response to
158: * the server.
159: */
1.35 itojun 160: static void
1.1 markus 161: respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv)
162: {
1.13 markus 163: u_char buf[32], response[16];
1.1 markus 164: MD5_CTX md;
165: int i, len;
166:
167: /* Decrypt the challenge using the private key. */
1.21 markus 168: /* XXX think about Bleichenbacher, too */
169: if (rsa_private_decrypt(challenge, challenge, prv) <= 0)
170: packet_disconnect(
171: "respond_to_rsa_challenge: rsa_private_decrypt failed");
1.1 markus 172:
173: /* Compute the response. */
174: /* The response is MD5 of decrypted challenge plus session id. */
175: len = BN_num_bytes(challenge);
176: if (len <= 0 || len > sizeof(buf))
1.21 markus 177: packet_disconnect(
178: "respond_to_rsa_challenge: bad challenge length %d", len);
1.1 markus 179:
180: memset(buf, 0, sizeof(buf));
181: BN_bn2bin(challenge, buf + sizeof(buf) - len);
182: MD5_Init(&md);
183: MD5_Update(&md, buf, 32);
184: MD5_Update(&md, session_id, 16);
185: MD5_Final(response, &md);
186:
187: debug("Sending response to host key RSA challenge.");
188:
189: /* Send the response back to the server. */
190: packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
191: for (i = 0; i < 16; i++)
192: packet_put_char(response[i]);
193: packet_send();
194: packet_write_wait();
195:
196: memset(buf, 0, sizeof(buf));
197: memset(response, 0, sizeof(response));
198: memset(&md, 0, sizeof(md));
199: }
200:
201: /*
202: * Checks if the user has authentication file, and if so, tries to authenticate
203: * the user using it.
204: */
1.35 itojun 205: static int
1.38 markus 206: try_rsa_authentication(int idx)
1.1 markus 207: {
208: BIGNUM *challenge;
1.36 markus 209: Key *public, *private;
1.38 markus 210: char buf[300], *passphrase, *comment, *authfile;
1.47 ! markus 211: int i, type, quit;
1.1 markus 212:
1.38 markus 213: public = options.identity_keys[idx];
214: authfile = options.identity_files[idx];
215: comment = xstrdup(authfile);
216:
1.1 markus 217: debug("Trying RSA authentication with key '%.100s'", comment);
218:
219: /* Tell the server that we are willing to authenticate using this key. */
220: packet_start(SSH_CMSG_AUTH_RSA);
221: packet_put_bignum(public->rsa->n);
222: packet_send();
223: packet_write_wait();
224:
225: /* Wait for server's response. */
1.47 ! markus 226: type = packet_read();
1.1 markus 227:
228: /*
229: * The server responds with failure if it doesn\'t like our key or
230: * doesn\'t support RSA authentication.
231: */
232: if (type == SSH_SMSG_FAILURE) {
233: debug("Server refused our key.");
234: xfree(comment);
235: return 0;
236: }
237: /* Otherwise, the server should respond with a challenge. */
238: if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
239: packet_disconnect("Protocol error during RSA authentication: %d", type);
240:
241: /* Get the challenge from the packet. */
1.43 markus 242: if ((challenge = BN_new()) == NULL)
243: fatal("try_rsa_authentication: BN_new failed");
1.46 markus 244: packet_get_bignum(challenge);
1.45 markus 245: packet_check_eom();
1.1 markus 246:
247: debug("Received RSA challenge from server.");
248:
249: /*
1.38 markus 250: * If the key is not stored in external hardware, we have to
251: * load the private key. Try first with empty passphrase; if it
1.1 markus 252: * fails, ask for a passphrase.
253: */
1.38 markus 254: if (public->flags && KEY_FLAG_EXT)
255: private = public;
256: else
257: private = key_load_private_type(KEY_RSA1, authfile, "", NULL);
1.36 markus 258: if (private == NULL && !options.batch_mode) {
259: snprintf(buf, sizeof(buf),
260: "Enter passphrase for RSA key '%.100s': ", comment);
261: for (i = 0; i < options.number_of_password_prompts; i++) {
1.1 markus 262: passphrase = read_passphrase(buf, 0);
1.36 markus 263: if (strcmp(passphrase, "") != 0) {
264: private = key_load_private_type(KEY_RSA1,
265: authfile, passphrase, NULL);
266: quit = 0;
267: } else {
268: debug2("no passphrase given, try next key");
269: quit = 1;
270: }
1.1 markus 271: memset(passphrase, 0, strlen(passphrase));
272: xfree(passphrase);
1.36 markus 273: if (private != NULL || quit)
274: break;
275: debug2("bad passphrase given, try again...");
1.1 markus 276: }
277: }
278: /* We no longer need the comment. */
279: xfree(comment);
1.36 markus 280:
281: if (private == NULL) {
282: if (!options.batch_mode)
283: error("Bad passphrase.");
284:
285: /* Send a dummy response packet to avoid protocol error. */
286: packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
287: for (i = 0; i < 16; i++)
288: packet_put_char(0);
289: packet_send();
290: packet_write_wait();
291:
292: /* Expect the server to reject it... */
1.47 ! markus 293: packet_read_expect(SSH_SMSG_FAILURE);
1.36 markus 294: BN_clear_free(challenge);
295: return 0;
296: }
1.1 markus 297:
298: /* Compute and send a response to the challenge. */
299: respond_to_rsa_challenge(challenge, private->rsa);
300:
1.38 markus 301: /* Destroy the private key unless it in external hardware. */
302: if (!(private->flags & KEY_FLAG_EXT))
303: key_free(private);
1.1 markus 304:
305: /* We no longer need the challenge. */
306: BN_clear_free(challenge);
307:
308: /* Wait for response from the server. */
1.47 ! markus 309: type = packet_read();
1.1 markus 310: if (type == SSH_SMSG_SUCCESS) {
311: debug("RSA authentication accepted by server.");
312: return 1;
313: }
314: if (type != SSH_SMSG_FAILURE)
315: packet_disconnect("Protocol error waiting RSA auth response: %d", type);
316: debug("RSA authentication refused.");
317: return 0;
318: }
319:
320: /*
321: * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv
322: * authentication and RSA host authentication.
323: */
1.35 itojun 324: static int
1.29 markus 325: try_rhosts_rsa_authentication(const char *local_user, Key * host_key)
1.1 markus 326: {
327: int type;
328: BIGNUM *challenge;
329:
330: debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication.");
331:
332: /* Tell the server that we are willing to authenticate using this key. */
333: packet_start(SSH_CMSG_AUTH_RHOSTS_RSA);
1.33 markus 334: packet_put_cstring(local_user);
1.29 markus 335: packet_put_int(BN_num_bits(host_key->rsa->n));
336: packet_put_bignum(host_key->rsa->e);
337: packet_put_bignum(host_key->rsa->n);
1.1 markus 338: packet_send();
339: packet_write_wait();
340:
341: /* Wait for server's response. */
1.47 ! markus 342: type = packet_read();
1.1 markus 343:
344: /* The server responds with failure if it doesn't admit our
345: .rhosts authentication or doesn't know our host key. */
346: if (type == SSH_SMSG_FAILURE) {
347: debug("Server refused our rhosts authentication or host key.");
348: return 0;
349: }
350: /* Otherwise, the server should respond with a challenge. */
351: if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
352: packet_disconnect("Protocol error during RSA authentication: %d", type);
353:
354: /* Get the challenge from the packet. */
1.43 markus 355: if ((challenge = BN_new()) == NULL)
356: fatal("try_rhosts_rsa_authentication: BN_new failed");
1.46 markus 357: packet_get_bignum(challenge);
1.45 markus 358: packet_check_eom();
1.1 markus 359:
360: debug("Received RSA challenge for host key from server.");
361:
362: /* Compute a response to the challenge. */
1.29 markus 363: respond_to_rsa_challenge(challenge, host_key->rsa);
1.1 markus 364:
365: /* We no longer need the challenge. */
366: BN_clear_free(challenge);
367:
368: /* Wait for response from the server. */
1.47 ! markus 369: type = packet_read();
1.1 markus 370: if (type == SSH_SMSG_SUCCESS) {
371: debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server.");
372: return 1;
373: }
374: if (type != SSH_SMSG_FAILURE)
375: packet_disconnect("Protocol error waiting RSA auth response: %d", type);
376: debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused.");
377: return 0;
378: }
379:
380: #ifdef KRB4
1.35 itojun 381: static int
1.37 dugsong 382: try_krb4_authentication(void)
1.1 markus 383: {
384: KTEXT_ST auth; /* Kerberos data */
385: char *reply;
386: char inst[INST_SZ];
387: char *realm;
388: CREDENTIALS cred;
1.47 ! markus 389: int r, type;
1.1 markus 390: socklen_t slen;
391: Key_schedule schedule;
392: u_long checksum, cksum;
393: MSG_DAT msg_data;
394: struct sockaddr_in local, foreign;
395: struct stat st;
396:
397: /* Don't do anything if we don't have any tickets. */
398: if (stat(tkt_string(), &st) < 0)
399: return 0;
1.42 deraadt 400:
1.37 dugsong 401: strlcpy(inst, (char *)krb_get_phost(get_canonical_hostname(1)),
402: INST_SZ);
1.42 deraadt 403:
1.37 dugsong 404: realm = (char *)krb_realmofhost(get_canonical_hostname(1));
1.1 markus 405: if (!realm) {
1.37 dugsong 406: debug("Kerberos v4: no realm for %s", get_canonical_hostname(1));
1.1 markus 407: return 0;
408: }
409: /* This can really be anything. */
1.37 dugsong 410: checksum = (u_long)getpid();
1.42 deraadt 411:
1.1 markus 412: r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum);
413: if (r != KSUCCESS) {
1.37 dugsong 414: debug("Kerberos v4 krb_mk_req failed: %s", krb_err_txt[r]);
1.1 markus 415: return 0;
416: }
417: /* Get session key to decrypt the server's reply with. */
418: r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred);
419: if (r != KSUCCESS) {
420: debug("get_cred failed: %s", krb_err_txt[r]);
421: return 0;
422: }
423: des_key_sched((des_cblock *) cred.session, schedule);
1.42 deraadt 424:
1.1 markus 425: /* Send authentication info to server. */
426: packet_start(SSH_CMSG_AUTH_KERBEROS);
427: packet_put_string((char *) auth.dat, auth.length);
428: packet_send();
429: packet_write_wait();
1.42 deraadt 430:
1.1 markus 431: /* Zero the buffer. */
432: (void) memset(auth.dat, 0, MAX_KTXT_LEN);
1.42 deraadt 433:
1.1 markus 434: slen = sizeof(local);
435: memset(&local, 0, sizeof(local));
436: if (getsockname(packet_get_connection_in(),
1.37 dugsong 437: (struct sockaddr *)&local, &slen) < 0)
1.1 markus 438: debug("getsockname failed: %s", strerror(errno));
1.42 deraadt 439:
1.1 markus 440: slen = sizeof(foreign);
441: memset(&foreign, 0, sizeof(foreign));
442: if (getpeername(packet_get_connection_in(),
1.37 dugsong 443: (struct sockaddr *)&foreign, &slen) < 0) {
1.1 markus 444: debug("getpeername failed: %s", strerror(errno));
445: fatal_cleanup();
446: }
447: /* Get server reply. */
1.47 ! markus 448: type = packet_read();
1.1 markus 449: switch (type) {
450: case SSH_SMSG_FAILURE:
451: /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */
1.37 dugsong 452: debug("Kerberos v4 authentication failed.");
1.1 markus 453: return 0;
454: break;
1.42 deraadt 455:
1.1 markus 456: case SSH_SMSG_AUTH_KERBEROS_RESPONSE:
457: /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */
1.37 dugsong 458: debug("Kerberos v4 authentication accepted.");
1.42 deraadt 459:
1.1 markus 460: /* Get server's response. */
1.13 markus 461: reply = packet_get_string((u_int *) &auth.length);
1.1 markus 462: memcpy(auth.dat, reply, auth.length);
463: xfree(reply);
1.42 deraadt 464:
1.45 markus 465: packet_check_eom();
1.42 deraadt 466:
1.1 markus 467: /*
468: * If his response isn't properly encrypted with the session
469: * key, and the decrypted checksum fails to match, he's
470: * bogus. Bail out.
471: */
472: r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session,
1.37 dugsong 473: &foreign, &local, &msg_data);
1.1 markus 474: if (r != KSUCCESS) {
1.37 dugsong 475: debug("Kerberos v4 krb_rd_priv failed: %s",
476: krb_err_txt[r]);
477: packet_disconnect("Kerberos v4 challenge failed!");
1.1 markus 478: }
479: /* Fetch the (incremented) checksum that we supplied in the request. */
1.37 dugsong 480: memcpy((char *)&cksum, (char *)msg_data.app_data,
481: sizeof(cksum));
1.1 markus 482: cksum = ntohl(cksum);
1.42 deraadt 483:
1.1 markus 484: /* If it matches, we're golden. */
485: if (cksum == checksum + 1) {
1.37 dugsong 486: debug("Kerberos v4 challenge successful.");
1.1 markus 487: return 1;
488: } else
1.37 dugsong 489: packet_disconnect("Kerberos v4 challenge failed!");
1.1 markus 490: break;
1.42 deraadt 491:
1.1 markus 492: default:
1.37 dugsong 493: packet_disconnect("Protocol error on Kerberos v4 response: %d", type);
1.1 markus 494: }
495: return 0;
496: }
497:
498: #endif /* KRB4 */
499:
1.37 dugsong 500: #ifdef KRB5
501: static int
502: try_krb5_authentication(krb5_context *context, krb5_auth_context *auth_context)
503: {
504: krb5_error_code problem;
505: const char *tkfile;
506: struct stat buf;
507: krb5_ccache ccache = NULL;
508: const char *remotehost;
509: krb5_data ap;
1.47 ! markus 510: int type;
1.37 dugsong 511: krb5_ap_rep_enc_part *reply = NULL;
512: int ret;
1.42 deraadt 513:
1.37 dugsong 514: memset(&ap, 0, sizeof(ap));
1.42 deraadt 515:
1.37 dugsong 516: problem = krb5_init_context(context);
517: if (problem) {
518: debug("Kerberos v5: krb5_init_context failed");
519: ret = 0;
520: goto out;
521: }
1.42 deraadt 522:
1.37 dugsong 523: tkfile = krb5_cc_default_name(*context);
524: if (strncmp(tkfile, "FILE:", 5) == 0)
525: tkfile += 5;
1.42 deraadt 526:
1.37 dugsong 527: if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) {
528: debug("Kerberos v5: could not get default ccache (permission denied).");
529: ret = 0;
530: goto out;
531: }
1.42 deraadt 532:
1.37 dugsong 533: problem = krb5_cc_default(*context, &ccache);
534: if (problem) {
535: debug("Kerberos v5: krb5_cc_default failed: %s",
536: krb5_get_err_text(*context, problem));
537: ret = 0;
538: goto out;
539: }
1.42 deraadt 540:
1.37 dugsong 541: remotehost = get_canonical_hostname(1);
1.42 deraadt 542:
1.37 dugsong 543: problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED,
544: "host", remotehost, NULL, ccache, &ap);
545: if (problem) {
546: debug("Kerberos v5: krb5_mk_req failed: %s",
547: krb5_get_err_text(*context, problem));
548: ret = 0;
549: goto out;
550: }
1.42 deraadt 551:
1.37 dugsong 552: packet_start(SSH_CMSG_AUTH_KERBEROS);
553: packet_put_string((char *) ap.data, ap.length);
554: packet_send();
555: packet_write_wait();
1.42 deraadt 556:
1.37 dugsong 557: xfree(ap.data);
558: ap.length = 0;
1.42 deraadt 559:
1.47 ! markus 560: type = packet_read();
1.37 dugsong 561: switch (type) {
1.42 deraadt 562: case SSH_SMSG_FAILURE:
563: /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */
564: debug("Kerberos v5 authentication failed.");
565: ret = 0;
566: break;
567:
1.37 dugsong 568: case SSH_SMSG_AUTH_KERBEROS_RESPONSE:
1.42 deraadt 569: /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */
570: debug("Kerberos v5 authentication accepted.");
571:
572: /* Get server's response. */
573: ap.data = packet_get_string((unsigned int *) &ap.length);
1.45 markus 574: packet_check_eom();
1.42 deraadt 575: /* XXX je to dobre? */
576:
577: problem = krb5_rd_rep(*context, *auth_context, &ap, &reply);
578: if (problem) {
1.37 dugsong 579: ret = 0;
580: }
581: ret = 1;
582: break;
1.42 deraadt 583:
1.37 dugsong 584: default:
585: packet_disconnect("Protocol error on Kerberos v5 response: %d",
586: type);
587: ret = 0;
588: break;
1.42 deraadt 589:
1.37 dugsong 590: }
1.42 deraadt 591:
1.37 dugsong 592: out:
593: if (ccache != NULL)
594: krb5_cc_close(*context, ccache);
595: if (reply != NULL)
596: krb5_free_ap_rep_enc_part(*context, reply);
597: if (ap.length > 0)
598: krb5_data_free(&ap);
1.42 deraadt 599:
1.37 dugsong 600: return (ret);
601: }
602:
603: static void
604: send_krb5_tgt(krb5_context context, krb5_auth_context auth_context)
605: {
1.47 ! markus 606: int fd, type;
1.37 dugsong 607: krb5_error_code problem;
608: krb5_data outbuf;
609: krb5_ccache ccache = NULL;
610: krb5_creds creds;
611: krb5_kdc_flags flags;
612: const char *remotehost;
1.42 deraadt 613:
1.37 dugsong 614: memset(&creds, 0, sizeof(creds));
615: memset(&outbuf, 0, sizeof(outbuf));
1.42 deraadt 616:
1.37 dugsong 617: fd = packet_get_connection_in();
1.42 deraadt 618:
1.37 dugsong 619: problem = krb5_auth_con_setaddrs_from_fd(context, auth_context, &fd);
620: if (problem)
621: goto out;
1.42 deraadt 622:
1.37 dugsong 623: problem = krb5_cc_default(context, &ccache);
624: if (problem)
625: goto out;
1.42 deraadt 626:
1.37 dugsong 627: problem = krb5_cc_get_principal(context, ccache, &creds.client);
628: if (problem)
629: goto out;
1.42 deraadt 630:
1.37 dugsong 631: problem = krb5_build_principal(context, &creds.server,
632: strlen(creds.client->realm), creds.client->realm,
633: "krbtgt", creds.client->realm, NULL);
634: if (problem)
635: goto out;
1.42 deraadt 636:
1.37 dugsong 637: creds.times.endtime = 0;
1.42 deraadt 638:
1.37 dugsong 639: flags.i = 0;
640: flags.b.forwarded = 1;
641: flags.b.forwardable = krb5_config_get_bool(context, NULL,
642: "libdefaults", "forwardable", NULL);
1.42 deraadt 643:
1.37 dugsong 644: remotehost = get_canonical_hostname(1);
1.42 deraadt 645:
1.37 dugsong 646: problem = krb5_get_forwarded_creds(context, auth_context,
647: ccache, flags.i, remotehost, &creds, &outbuf);
648: if (problem)
649: goto out;
1.42 deraadt 650:
1.37 dugsong 651: packet_start(SSH_CMSG_HAVE_KERBEROS_TGT);
652: packet_put_string((char *)outbuf.data, outbuf.length);
653: packet_send();
654: packet_write_wait();
1.42 deraadt 655:
1.47 ! markus 656: type = packet_read();
1.42 deraadt 657:
1.37 dugsong 658: if (type == SSH_SMSG_SUCCESS) {
659: char *pname;
1.42 deraadt 660:
1.37 dugsong 661: krb5_unparse_name(context, creds.client, &pname);
662: debug("Kerberos v5 TGT forwarded (%s).", pname);
663: xfree(pname);
664: } else
665: debug("Kerberos v5 TGT forwarding failed.");
1.42 deraadt 666:
1.37 dugsong 667: return;
1.42 deraadt 668:
1.37 dugsong 669: out:
670: if (problem)
671: debug("Kerberos v5 TGT forwarding failed: %s",
672: krb5_get_err_text(context, problem));
673: if (creds.client)
674: krb5_free_principal(context, creds.client);
675: if (creds.server)
676: krb5_free_principal(context, creds.server);
677: if (ccache)
678: krb5_cc_close(context, ccache);
679: if (outbuf.data)
680: xfree(outbuf.data);
681: }
682: #endif /* KRB5 */
683:
1.1 markus 684: #ifdef AFS
1.37 dugsong 685: static void
686: send_krb4_tgt(void)
1.1 markus 687: {
688: CREDENTIALS *creds;
689: struct stat st;
1.37 dugsong 690: char buffer[4096], pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ];
1.47 ! markus 691: int problem, type;
1.42 deraadt 692:
1.1 markus 693: /* Don't do anything if we don't have any tickets. */
694: if (stat(tkt_string(), &st) < 0)
1.37 dugsong 695: return;
1.42 deraadt 696:
1.1 markus 697: creds = xmalloc(sizeof(*creds));
1.42 deraadt 698:
1.37 dugsong 699: problem = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm);
700: if (problem)
701: goto out;
1.42 deraadt 702:
1.37 dugsong 703: problem = krb_get_cred("krbtgt", prealm, prealm, creds);
704: if (problem)
705: goto out;
1.42 deraadt 706:
1.1 markus 707: if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) {
1.37 dugsong 708: problem = RD_AP_EXP;
709: goto out;
1.1 markus 710: }
1.37 dugsong 711: creds_to_radix(creds, (u_char *)buffer, sizeof(buffer));
1.42 deraadt 712:
1.1 markus 713: packet_start(SSH_CMSG_HAVE_KERBEROS_TGT);
1.33 markus 714: packet_put_cstring(buffer);
1.1 markus 715: packet_send();
716: packet_write_wait();
1.42 deraadt 717:
1.47 ! markus 718: type = packet_read();
1.42 deraadt 719:
1.37 dugsong 720: if (type == SSH_SMSG_SUCCESS)
721: debug("Kerberos v4 TGT forwarded (%s%s%s@%s).",
722: creds->pname, creds->pinst[0] ? "." : "",
723: creds->pinst, creds->realm);
724: else
725: debug("Kerberos v4 TGT rejected.");
1.42 deraadt 726:
1.37 dugsong 727: xfree(creds);
728: return;
1.42 deraadt 729:
1.37 dugsong 730: out:
731: debug("Kerberos v4 TGT passing failed: %s", krb_err_txt[problem]);
732: xfree(creds);
1.1 markus 733: }
734:
1.35 itojun 735: static void
1.1 markus 736: send_afs_tokens(void)
737: {
738: CREDENTIALS creds;
739: struct ViceIoctl parms;
740: struct ClearToken ct;
1.37 dugsong 741: int i, type, len;
1.1 markus 742: char buf[2048], *p, *server_cell;
743: char buffer[8192];
1.42 deraadt 744:
1.1 markus 745: /* Move over ktc_GetToken, here's something leaner. */
746: for (i = 0; i < 100; i++) { /* just in case */
747: parms.in = (char *) &i;
748: parms.in_size = sizeof(i);
749: parms.out = buf;
750: parms.out_size = sizeof(buf);
751: if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0)
752: break;
753: p = buf;
1.42 deraadt 754:
1.1 markus 755: /* Get secret token. */
1.13 markus 756: memcpy(&creds.ticket_st.length, p, sizeof(u_int));
1.1 markus 757: if (creds.ticket_st.length > MAX_KTXT_LEN)
758: break;
1.13 markus 759: p += sizeof(u_int);
1.1 markus 760: memcpy(creds.ticket_st.dat, p, creds.ticket_st.length);
761: p += creds.ticket_st.length;
1.42 deraadt 762:
1.1 markus 763: /* Get clear token. */
764: memcpy(&len, p, sizeof(len));
765: if (len != sizeof(struct ClearToken))
766: break;
767: p += sizeof(len);
768: memcpy(&ct, p, len);
769: p += len;
770: p += sizeof(len); /* primary flag */
771: server_cell = p;
1.42 deraadt 772:
1.1 markus 773: /* Flesh out our credentials. */
1.37 dugsong 774: strlcpy(creds.service, "afs", sizeof(creds.service));
1.1 markus 775: creds.instance[0] = '\0';
776: strlcpy(creds.realm, server_cell, REALM_SZ);
777: memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ);
778: creds.issue_date = ct.BeginTimestamp;
1.37 dugsong 779: creds.lifetime = krb_time_to_life(creds.issue_date,
780: ct.EndTimestamp);
1.1 markus 781: creds.kvno = ct.AuthHandle;
782: snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId);
783: creds.pinst[0] = '\0';
1.42 deraadt 784:
1.1 markus 785: /* Encode token, ship it off. */
1.37 dugsong 786: if (creds_to_radix(&creds, (u_char *)buffer,
787: sizeof(buffer)) <= 0)
1.1 markus 788: break;
789: packet_start(SSH_CMSG_HAVE_AFS_TOKEN);
1.33 markus 790: packet_put_cstring(buffer);
1.1 markus 791: packet_send();
792: packet_write_wait();
793:
794: /* Roger, Roger. Clearance, Clarence. What's your vector,
795: Victor? */
1.47 ! markus 796: type = packet_read();
1.42 deraadt 797:
1.1 markus 798: if (type == SSH_SMSG_FAILURE)
799: debug("AFS token for cell %s rejected.", server_cell);
800: else if (type != SSH_SMSG_SUCCESS)
801: packet_disconnect("Protocol error on AFS token response: %d", type);
802: }
803: }
804:
805: #endif /* AFS */
806:
807: /*
808: * Tries to authenticate with any string-based challenge/response system.
809: * Note that the client code is not tied to s/key or TIS.
810: */
1.35 itojun 811: static int
1.32 markus 812: try_challenge_response_authentication(void)
1.1 markus 813: {
814: int type, i;
1.13 markus 815: u_int clen;
1.12 markus 816: char prompt[1024];
1.1 markus 817: char *challenge, *response;
1.40 markus 818:
819: debug("Doing challenge response authentication.");
820:
1.12 markus 821: for (i = 0; i < options.number_of_password_prompts; i++) {
822: /* request a challenge */
823: packet_start(SSH_CMSG_AUTH_TIS);
824: packet_send();
825: packet_write_wait();
1.1 markus 826:
1.47 ! markus 827: type = packet_read();
1.12 markus 828: if (type != SSH_SMSG_FAILURE &&
829: type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
830: packet_disconnect("Protocol error: got %d in response "
1.20 markus 831: "to SSH_CMSG_AUTH_TIS", type);
1.12 markus 832: }
833: if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
1.20 markus 834: debug("No challenge.");
1.12 markus 835: return 0;
836: }
837: challenge = packet_get_string(&clen);
1.45 markus 838: packet_check_eom();
1.16 markus 839: snprintf(prompt, sizeof prompt, "%s%s", challenge,
1.42 deraadt 840: strchr(challenge, '\n') ? "" : "\nResponse: ");
1.12 markus 841: xfree(challenge);
1.1 markus 842: if (i != 0)
843: error("Permission denied, please try again.");
1.12 markus 844: if (options.cipher == SSH_CIPHER_NONE)
845: log("WARNING: Encryption is disabled! "
846: "Reponse will be transmitted in clear text.");
847: response = read_passphrase(prompt, 0);
848: if (strcmp(response, "") == 0) {
849: xfree(response);
850: break;
851: }
1.1 markus 852: packet_start(SSH_CMSG_AUTH_TIS_RESPONSE);
1.27 markus 853: ssh_put_password(response);
1.1 markus 854: memset(response, 0, strlen(response));
855: xfree(response);
856: packet_send();
857: packet_write_wait();
1.47 ! markus 858: type = packet_read();
1.1 markus 859: if (type == SSH_SMSG_SUCCESS)
860: return 1;
861: if (type != SSH_SMSG_FAILURE)
862: packet_disconnect("Protocol error: got %d in response "
1.20 markus 863: "to SSH_CMSG_AUTH_TIS_RESPONSE", type);
1.1 markus 864: }
865: /* failure */
866: return 0;
867: }
868:
869: /*
870: * Tries to authenticate with plain passwd authentication.
871: */
1.35 itojun 872: static int
1.1 markus 873: try_password_authentication(char *prompt)
874: {
1.47 ! markus 875: int type, i;
1.1 markus 876: char *password;
877:
878: debug("Doing password authentication.");
879: if (options.cipher == SSH_CIPHER_NONE)
880: log("WARNING: Encryption is disabled! Password will be transmitted in clear text.");
881: for (i = 0; i < options.number_of_password_prompts; i++) {
882: if (i != 0)
883: error("Permission denied, please try again.");
884: password = read_passphrase(prompt, 0);
885: packet_start(SSH_CMSG_AUTH_PASSWORD);
1.27 markus 886: ssh_put_password(password);
1.1 markus 887: memset(password, 0, strlen(password));
888: xfree(password);
889: packet_send();
890: packet_write_wait();
891:
1.47 ! markus 892: type = packet_read();
1.1 markus 893: if (type == SSH_SMSG_SUCCESS)
894: return 1;
895: if (type != SSH_SMSG_FAILURE)
896: packet_disconnect("Protocol error: got %d in response to passwd auth", type);
897: }
898: /* failure */
899: return 0;
900: }
901:
902: /*
903: * SSH1 key exchange
904: */
905: void
906: ssh_kex(char *host, struct sockaddr *hostaddr)
907: {
908: int i;
909: BIGNUM *key;
1.43 markus 910: Key *host_key, *server_key;
1.1 markus 911: int bits, rbits;
912: int ssh_cipher_default = SSH_CIPHER_3DES;
1.13 markus 913: u_char session_key[SSH_SESSION_KEY_LENGTH];
914: u_char cookie[8];
915: u_int supported_ciphers;
916: u_int server_flags, client_flags;
1.1 markus 917: u_int32_t rand = 0;
918:
919: debug("Waiting for server public key.");
920:
921: /* Wait for a public key packet from the server. */
1.47 ! markus 922: packet_read_expect(SSH_SMSG_PUBLIC_KEY);
1.1 markus 923:
924: /* Get cookie from the packet. */
925: for (i = 0; i < 8; i++)
926: cookie[i] = packet_get_char();
927:
928: /* Get the public key. */
1.43 markus 929: server_key = key_new(KEY_RSA1);
930: bits = packet_get_int();
1.46 markus 931: packet_get_bignum(server_key->rsa->e);
932: packet_get_bignum(server_key->rsa->n);
1.1 markus 933:
1.43 markus 934: rbits = BN_num_bits(server_key->rsa->n);
1.1 markus 935: if (bits != rbits) {
936: log("Warning: Server lies about size of server public key: "
937: "actual size is %d bits vs. announced %d.", rbits, bits);
938: log("Warning: This may be due to an old implementation of ssh.");
939: }
940: /* Get the host key. */
1.43 markus 941: host_key = key_new(KEY_RSA1);
942: bits = packet_get_int();
1.46 markus 943: packet_get_bignum(host_key->rsa->e);
944: packet_get_bignum(host_key->rsa->n);
1.1 markus 945:
1.43 markus 946: rbits = BN_num_bits(host_key->rsa->n);
1.1 markus 947: if (bits != rbits) {
948: log("Warning: Server lies about size of server host key: "
949: "actual size is %d bits vs. announced %d.", rbits, bits);
950: log("Warning: This may be due to an old implementation of ssh.");
951: }
952:
953: /* Get protocol flags. */
954: server_flags = packet_get_int();
955: packet_set_protocol_flags(server_flags);
956:
957: supported_ciphers = packet_get_int();
958: supported_authentications = packet_get_int();
1.45 markus 959: packet_check_eom();
1.1 markus 960:
961: debug("Received server public key (%d bits) and host key (%d bits).",
1.43 markus 962: BN_num_bits(server_key->rsa->n), BN_num_bits(host_key->rsa->n));
1.1 markus 963:
1.43 markus 964: if (verify_host_key(host, hostaddr, host_key) == -1)
1.41 markus 965: fatal("Host key verification failed.");
1.1 markus 966:
967: client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN;
968:
1.43 markus 969: compute_session_id(session_id, cookie, host_key->rsa->n, server_key->rsa->n);
1.1 markus 970:
971: /* Generate a session key. */
972: arc4random_stir();
973:
974: /*
975: * Generate an encryption key for the session. The key is a 256 bit
976: * random number, interpreted as a 32-byte key, with the least
977: * significant 8 bits being the first byte of the key.
978: */
979: for (i = 0; i < 32; i++) {
980: if (i % 4 == 0)
981: rand = arc4random();
982: session_key[i] = rand & 0xff;
983: rand >>= 8;
984: }
985:
986: /*
987: * According to the protocol spec, the first byte of the session key
988: * is the highest byte of the integer. The session key is xored with
989: * the first 16 bytes of the session id.
990: */
1.43 markus 991: if ((key = BN_new()) == NULL)
992: fatal("respond_to_rsa_challenge: BN_new failed");
1.1 markus 993: BN_set_word(key, 0);
994: for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
995: BN_lshift(key, key, 8);
996: if (i < 16)
997: BN_add_word(key, session_key[i] ^ session_id[i]);
998: else
999: BN_add_word(key, session_key[i]);
1000: }
1001:
1002: /*
1003: * Encrypt the integer using the public key and host key of the
1004: * server (key with smaller modulus first).
1005: */
1.43 markus 1006: if (BN_cmp(server_key->rsa->n, host_key->rsa->n) < 0) {
1.1 markus 1007: /* Public key has smaller modulus. */
1.43 markus 1008: if (BN_num_bits(host_key->rsa->n) <
1009: BN_num_bits(server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1010: fatal("respond_to_rsa_challenge: host_key %d < server_key %d + "
1.42 deraadt 1011: "SSH_KEY_BITS_RESERVED %d",
1.43 markus 1012: BN_num_bits(host_key->rsa->n),
1013: BN_num_bits(server_key->rsa->n),
1.42 deraadt 1014: SSH_KEY_BITS_RESERVED);
1.1 markus 1015: }
1.43 markus 1016: rsa_public_encrypt(key, key, server_key->rsa);
1017: rsa_public_encrypt(key, key, host_key->rsa);
1.1 markus 1018: } else {
1019: /* Host key has smaller modulus (or they are equal). */
1.43 markus 1020: if (BN_num_bits(server_key->rsa->n) <
1021: BN_num_bits(host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1022: fatal("respond_to_rsa_challenge: server_key %d < host_key %d + "
1.42 deraadt 1023: "SSH_KEY_BITS_RESERVED %d",
1.43 markus 1024: BN_num_bits(server_key->rsa->n),
1025: BN_num_bits(host_key->rsa->n),
1.42 deraadt 1026: SSH_KEY_BITS_RESERVED);
1.1 markus 1027: }
1.43 markus 1028: rsa_public_encrypt(key, key, host_key->rsa);
1029: rsa_public_encrypt(key, key, server_key->rsa);
1.1 markus 1030: }
1031:
1032: /* Destroy the public keys since we no longer need them. */
1.43 markus 1033: key_free(server_key);
1034: key_free(host_key);
1.1 markus 1035:
1.11 markus 1036: if (options.cipher == SSH_CIPHER_NOT_SET) {
1037: if (cipher_mask_ssh1(1) & supported_ciphers & (1 << ssh_cipher_default))
1038: options.cipher = ssh_cipher_default;
1039: } else if (options.cipher == SSH_CIPHER_ILLEGAL ||
1.10 markus 1040: !(cipher_mask_ssh1(1) & (1 << options.cipher))) {
1.3 markus 1041: log("No valid SSH1 cipher, using %.100s instead.",
1.7 markus 1042: cipher_name(ssh_cipher_default));
1043: options.cipher = ssh_cipher_default;
1.1 markus 1044: }
1045: /* Check that the selected cipher is supported. */
1046: if (!(supported_ciphers & (1 << options.cipher)))
1047: fatal("Selected cipher type %.100s not supported by server.",
1.42 deraadt 1048: cipher_name(options.cipher));
1.1 markus 1049:
1050: debug("Encryption type: %.100s", cipher_name(options.cipher));
1051:
1052: /* Send the encrypted session key to the server. */
1053: packet_start(SSH_CMSG_SESSION_KEY);
1054: packet_put_char(options.cipher);
1055:
1056: /* Send the cookie back to the server. */
1057: for (i = 0; i < 8; i++)
1058: packet_put_char(cookie[i]);
1059:
1060: /* Send and destroy the encrypted encryption key integer. */
1061: packet_put_bignum(key);
1062: BN_clear_free(key);
1063:
1064: /* Send protocol flags. */
1065: packet_put_int(client_flags);
1066:
1067: /* Send the packet now. */
1068: packet_send();
1069: packet_write_wait();
1070:
1071: debug("Sent encrypted session key.");
1072:
1073: /* Set the encryption key. */
1074: packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher);
1075:
1076: /* We will no longer need the session key here. Destroy any extra copies. */
1077: memset(session_key, 0, sizeof(session_key));
1078:
1079: /*
1080: * Expect a success message from the server. Note that this message
1081: * will be received in encrypted form.
1082: */
1.47 ! markus 1083: packet_read_expect(SSH_SMSG_SUCCESS);
1.1 markus 1084:
1085: debug("Received encrypted confirmation.");
1086: }
1087:
1088: /*
1089: * Authenticate user
1090: */
1091: void
1.30 markus 1092: ssh_userauth1(const char *local_user, const char *server_user, char *host,
1093: Key **keys, int nkeys)
1.1 markus 1094: {
1.37 dugsong 1095: #ifdef KRB5
1096: krb5_context context = NULL;
1097: krb5_auth_context auth_context = NULL;
1098: #endif
1.1 markus 1099: int i, type;
1.42 deraadt 1100:
1.1 markus 1101: if (supported_authentications == 0)
1.30 markus 1102: fatal("ssh_userauth1: server supports no auth methods");
1.1 markus 1103:
1104: /* Send the name of the user to log in as on the server. */
1105: packet_start(SSH_CMSG_USER);
1.33 markus 1106: packet_put_cstring(server_user);
1.1 markus 1107: packet_send();
1108: packet_write_wait();
1109:
1110: /*
1111: * The server should respond with success if no authentication is
1112: * needed (the user has no password). Otherwise the server responds
1113: * with failure.
1114: */
1.47 ! markus 1115: type = packet_read();
1.1 markus 1116:
1117: /* check whether the connection was accepted without authentication. */
1118: if (type == SSH_SMSG_SUCCESS)
1.37 dugsong 1119: goto success;
1.1 markus 1120: if (type != SSH_SMSG_FAILURE)
1.37 dugsong 1121: packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", type);
1.42 deraadt 1122:
1.37 dugsong 1123: #ifdef KRB5
1124: if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) &&
1.42 deraadt 1125: options.kerberos_authentication) {
1.37 dugsong 1126: debug("Trying Kerberos v5 authentication.");
1.42 deraadt 1127:
1.37 dugsong 1128: if (try_krb5_authentication(&context, &auth_context)) {
1.47 ! markus 1129: type = packet_read();
1.37 dugsong 1130: if (type == SSH_SMSG_SUCCESS)
1131: goto success;
1132: if (type != SSH_SMSG_FAILURE)
1133: packet_disconnect("Protocol error: got %d in response to Kerberos v5 auth", type);
1134: }
1.1 markus 1135: }
1.37 dugsong 1136: #endif /* KRB5 */
1.42 deraadt 1137:
1.1 markus 1138: #ifdef KRB4
1139: if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) &&
1140: options.kerberos_authentication) {
1.37 dugsong 1141: debug("Trying Kerberos v4 authentication.");
1.42 deraadt 1142:
1.37 dugsong 1143: if (try_krb4_authentication()) {
1.47 ! markus 1144: type = packet_read();
1.1 markus 1145: if (type == SSH_SMSG_SUCCESS)
1.37 dugsong 1146: goto success;
1.1 markus 1147: if (type != SSH_SMSG_FAILURE)
1.37 dugsong 1148: packet_disconnect("Protocol error: got %d in response to Kerberos v4 auth", type);
1.1 markus 1149: }
1150: }
1151: #endif /* KRB4 */
1.42 deraadt 1152:
1.1 markus 1153: /*
1154: * Use rhosts authentication if running in privileged socket and we
1155: * do not wish to remain anonymous.
1156: */
1157: if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) &&
1158: options.rhosts_authentication) {
1159: debug("Trying rhosts authentication.");
1160: packet_start(SSH_CMSG_AUTH_RHOSTS);
1.33 markus 1161: packet_put_cstring(local_user);
1.1 markus 1162: packet_send();
1163: packet_write_wait();
1164:
1165: /* The server should respond with success or failure. */
1.47 ! markus 1166: type = packet_read();
1.1 markus 1167: if (type == SSH_SMSG_SUCCESS)
1.37 dugsong 1168: goto success;
1.1 markus 1169: if (type != SSH_SMSG_FAILURE)
1170: packet_disconnect("Protocol error: got %d in response to rhosts auth",
1171: type);
1172: }
1173: /*
1174: * Try .rhosts or /etc/hosts.equiv authentication with RSA host
1175: * authentication.
1176: */
1177: if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) &&
1.30 markus 1178: options.rhosts_rsa_authentication) {
1179: for (i = 0; i < nkeys; i++) {
1.31 markus 1180: if (keys[i] != NULL && keys[i]->type == KEY_RSA1 &&
1.30 markus 1181: try_rhosts_rsa_authentication(local_user, keys[i]))
1.37 dugsong 1182: goto success;
1.30 markus 1183: }
1.1 markus 1184: }
1185: /* Try RSA authentication if the server supports it. */
1186: if ((supported_authentications & (1 << SSH_AUTH_RSA)) &&
1187: options.rsa_authentication) {
1188: /*
1189: * Try RSA authentication using the authentication agent. The
1190: * agent is tried first because no passphrase is needed for
1191: * it, whereas identity files may require passphrases.
1192: */
1193: if (try_agent_authentication())
1.37 dugsong 1194: goto success;
1.1 markus 1195:
1196: /* Try RSA authentication for each identity. */
1197: for (i = 0; i < options.num_identity_files; i++)
1.28 markus 1198: if (options.identity_keys[i] != NULL &&
1199: options.identity_keys[i]->type == KEY_RSA1 &&
1.38 markus 1200: try_rsa_authentication(i))
1.37 dugsong 1201: goto success;
1.1 markus 1202: }
1.20 markus 1203: /* Try challenge response authentication if the server supports it. */
1.1 markus 1204: if ((supported_authentications & (1 << SSH_AUTH_TIS)) &&
1.32 markus 1205: options.challenge_response_authentication && !options.batch_mode) {
1206: if (try_challenge_response_authentication())
1.37 dugsong 1207: goto success;
1.1 markus 1208: }
1209: /* Try password authentication if the server supports it. */
1210: if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) &&
1211: options.password_authentication && !options.batch_mode) {
1212: char prompt[80];
1213:
1.23 itojun 1214: snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1.1 markus 1215: server_user, host);
1216: if (try_password_authentication(prompt))
1.37 dugsong 1217: goto success;
1.1 markus 1218: }
1219: /* All authentication methods have failed. Exit with an error message. */
1220: fatal("Permission denied.");
1221: /* NOTREACHED */
1.37 dugsong 1222:
1223: success:
1224: #ifdef KRB5
1225: /* Try Kerberos v5 TGT passing. */
1226: if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&
1227: options.kerberos_tgt_passing && context && auth_context) {
1228: if (options.cipher == SSH_CIPHER_NONE)
1229: log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");
1230: send_krb5_tgt(context, auth_context);
1231: }
1232: if (auth_context)
1233: krb5_auth_con_free(context, auth_context);
1234: if (context)
1235: krb5_free_context(context);
1236: #endif
1.42 deraadt 1237:
1.37 dugsong 1238: #ifdef AFS
1239: /* Try Kerberos v4 TGT passing if the server supports it. */
1240: if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&
1241: options.kerberos_tgt_passing) {
1242: if (options.cipher == SSH_CIPHER_NONE)
1243: log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");
1244: send_krb4_tgt();
1245: }
1246: /* Try AFS token passing if the server supports it. */
1247: if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) &&
1248: options.afs_token_passing && k_hasafs()) {
1249: if (options.cipher == SSH_CIPHER_NONE)
1250: log("WARNING: Encryption is disabled! Token will be transmitted in the clear!");
1251: send_afs_tokens();
1252: }
1253: #endif /* AFS */
1.39 stevesk 1254:
1255: return; /* need statement after label */
1.1 markus 1256: }