Annotation of src/usr.bin/ssh/sshconnect1.c, Revision 1.49
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"
1.49 ! markus 16: RCSID("$OpenBSD: sshconnect1.c,v 1.48 2002/02/11 16:15:46 markus Exp $");
1.1 markus 17:
18: #include <openssl/bn.h>
1.48 markus 19: #include <openssl/md5.h>
1.1 markus 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);
1.49 ! markus 462: if (auth.length >= MAX_KTXT_LEN)
! 463: fatal("Kerberos v4: Malformed response from server");
1.1 markus 464: memcpy(auth.dat, reply, auth.length);
465: xfree(reply);
1.42 deraadt 466:
1.45 markus 467: packet_check_eom();
1.42 deraadt 468:
1.1 markus 469: /*
470: * If his response isn't properly encrypted with the session
471: * key, and the decrypted checksum fails to match, he's
472: * bogus. Bail out.
473: */
474: r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session,
1.37 dugsong 475: &foreign, &local, &msg_data);
1.1 markus 476: if (r != KSUCCESS) {
1.37 dugsong 477: debug("Kerberos v4 krb_rd_priv failed: %s",
478: krb_err_txt[r]);
479: packet_disconnect("Kerberos v4 challenge failed!");
1.1 markus 480: }
481: /* Fetch the (incremented) checksum that we supplied in the request. */
1.37 dugsong 482: memcpy((char *)&cksum, (char *)msg_data.app_data,
483: sizeof(cksum));
1.1 markus 484: cksum = ntohl(cksum);
1.42 deraadt 485:
1.1 markus 486: /* If it matches, we're golden. */
487: if (cksum == checksum + 1) {
1.37 dugsong 488: debug("Kerberos v4 challenge successful.");
1.1 markus 489: return 1;
490: } else
1.37 dugsong 491: packet_disconnect("Kerberos v4 challenge failed!");
1.1 markus 492: break;
1.42 deraadt 493:
1.1 markus 494: default:
1.37 dugsong 495: packet_disconnect("Protocol error on Kerberos v4 response: %d", type);
1.1 markus 496: }
497: return 0;
498: }
499:
500: #endif /* KRB4 */
501:
1.37 dugsong 502: #ifdef KRB5
503: static int
504: try_krb5_authentication(krb5_context *context, krb5_auth_context *auth_context)
505: {
506: krb5_error_code problem;
507: const char *tkfile;
508: struct stat buf;
509: krb5_ccache ccache = NULL;
510: const char *remotehost;
511: krb5_data ap;
1.47 markus 512: int type;
1.37 dugsong 513: krb5_ap_rep_enc_part *reply = NULL;
514: int ret;
1.42 deraadt 515:
1.37 dugsong 516: memset(&ap, 0, sizeof(ap));
1.42 deraadt 517:
1.37 dugsong 518: problem = krb5_init_context(context);
519: if (problem) {
520: debug("Kerberos v5: krb5_init_context failed");
521: ret = 0;
522: goto out;
523: }
1.42 deraadt 524:
1.37 dugsong 525: tkfile = krb5_cc_default_name(*context);
526: if (strncmp(tkfile, "FILE:", 5) == 0)
527: tkfile += 5;
1.42 deraadt 528:
1.37 dugsong 529: if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) {
530: debug("Kerberos v5: could not get default ccache (permission denied).");
531: ret = 0;
532: goto out;
533: }
1.42 deraadt 534:
1.37 dugsong 535: problem = krb5_cc_default(*context, &ccache);
536: if (problem) {
537: debug("Kerberos v5: krb5_cc_default failed: %s",
538: krb5_get_err_text(*context, problem));
539: ret = 0;
540: goto out;
541: }
1.42 deraadt 542:
1.37 dugsong 543: remotehost = get_canonical_hostname(1);
1.42 deraadt 544:
1.37 dugsong 545: problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED,
546: "host", remotehost, NULL, ccache, &ap);
547: if (problem) {
548: debug("Kerberos v5: krb5_mk_req failed: %s",
549: krb5_get_err_text(*context, problem));
550: ret = 0;
551: goto out;
552: }
1.42 deraadt 553:
1.37 dugsong 554: packet_start(SSH_CMSG_AUTH_KERBEROS);
555: packet_put_string((char *) ap.data, ap.length);
556: packet_send();
557: packet_write_wait();
1.42 deraadt 558:
1.37 dugsong 559: xfree(ap.data);
560: ap.length = 0;
1.42 deraadt 561:
1.47 markus 562: type = packet_read();
1.37 dugsong 563: switch (type) {
1.42 deraadt 564: case SSH_SMSG_FAILURE:
565: /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */
566: debug("Kerberos v5 authentication failed.");
567: ret = 0;
568: break;
569:
1.37 dugsong 570: case SSH_SMSG_AUTH_KERBEROS_RESPONSE:
1.42 deraadt 571: /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */
572: debug("Kerberos v5 authentication accepted.");
573:
574: /* Get server's response. */
575: ap.data = packet_get_string((unsigned int *) &ap.length);
1.45 markus 576: packet_check_eom();
1.42 deraadt 577: /* XXX je to dobre? */
578:
579: problem = krb5_rd_rep(*context, *auth_context, &ap, &reply);
580: if (problem) {
1.37 dugsong 581: ret = 0;
582: }
583: ret = 1;
584: break;
1.42 deraadt 585:
1.37 dugsong 586: default:
587: packet_disconnect("Protocol error on Kerberos v5 response: %d",
588: type);
589: ret = 0;
590: break;
1.42 deraadt 591:
1.37 dugsong 592: }
1.42 deraadt 593:
1.37 dugsong 594: out:
595: if (ccache != NULL)
596: krb5_cc_close(*context, ccache);
597: if (reply != NULL)
598: krb5_free_ap_rep_enc_part(*context, reply);
599: if (ap.length > 0)
600: krb5_data_free(&ap);
1.42 deraadt 601:
1.37 dugsong 602: return (ret);
603: }
604:
605: static void
606: send_krb5_tgt(krb5_context context, krb5_auth_context auth_context)
607: {
1.47 markus 608: int fd, type;
1.37 dugsong 609: krb5_error_code problem;
610: krb5_data outbuf;
611: krb5_ccache ccache = NULL;
612: krb5_creds creds;
613: krb5_kdc_flags flags;
614: const char *remotehost;
1.42 deraadt 615:
1.37 dugsong 616: memset(&creds, 0, sizeof(creds));
617: memset(&outbuf, 0, sizeof(outbuf));
1.42 deraadt 618:
1.37 dugsong 619: fd = packet_get_connection_in();
1.42 deraadt 620:
1.37 dugsong 621: problem = krb5_auth_con_setaddrs_from_fd(context, auth_context, &fd);
622: if (problem)
623: goto out;
1.42 deraadt 624:
1.37 dugsong 625: problem = krb5_cc_default(context, &ccache);
626: if (problem)
627: goto out;
1.42 deraadt 628:
1.37 dugsong 629: problem = krb5_cc_get_principal(context, ccache, &creds.client);
630: if (problem)
631: goto out;
1.42 deraadt 632:
1.37 dugsong 633: problem = krb5_build_principal(context, &creds.server,
634: strlen(creds.client->realm), creds.client->realm,
635: "krbtgt", creds.client->realm, NULL);
636: if (problem)
637: goto out;
1.42 deraadt 638:
1.37 dugsong 639: creds.times.endtime = 0;
1.42 deraadt 640:
1.37 dugsong 641: flags.i = 0;
642: flags.b.forwarded = 1;
643: flags.b.forwardable = krb5_config_get_bool(context, NULL,
644: "libdefaults", "forwardable", NULL);
1.42 deraadt 645:
1.37 dugsong 646: remotehost = get_canonical_hostname(1);
1.42 deraadt 647:
1.37 dugsong 648: problem = krb5_get_forwarded_creds(context, auth_context,
649: ccache, flags.i, remotehost, &creds, &outbuf);
650: if (problem)
651: goto out;
1.42 deraadt 652:
1.37 dugsong 653: packet_start(SSH_CMSG_HAVE_KERBEROS_TGT);
654: packet_put_string((char *)outbuf.data, outbuf.length);
655: packet_send();
656: packet_write_wait();
1.42 deraadt 657:
1.47 markus 658: type = packet_read();
1.42 deraadt 659:
1.37 dugsong 660: if (type == SSH_SMSG_SUCCESS) {
661: char *pname;
1.42 deraadt 662:
1.37 dugsong 663: krb5_unparse_name(context, creds.client, &pname);
664: debug("Kerberos v5 TGT forwarded (%s).", pname);
665: xfree(pname);
666: } else
667: debug("Kerberos v5 TGT forwarding failed.");
1.42 deraadt 668:
1.37 dugsong 669: return;
1.42 deraadt 670:
1.37 dugsong 671: out:
672: if (problem)
673: debug("Kerberos v5 TGT forwarding failed: %s",
674: krb5_get_err_text(context, problem));
675: if (creds.client)
676: krb5_free_principal(context, creds.client);
677: if (creds.server)
678: krb5_free_principal(context, creds.server);
679: if (ccache)
680: krb5_cc_close(context, ccache);
681: if (outbuf.data)
682: xfree(outbuf.data);
683: }
684: #endif /* KRB5 */
685:
1.1 markus 686: #ifdef AFS
1.37 dugsong 687: static void
688: send_krb4_tgt(void)
1.1 markus 689: {
690: CREDENTIALS *creds;
691: struct stat st;
1.37 dugsong 692: char buffer[4096], pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ];
1.47 markus 693: int problem, type;
1.42 deraadt 694:
1.1 markus 695: /* Don't do anything if we don't have any tickets. */
696: if (stat(tkt_string(), &st) < 0)
1.37 dugsong 697: return;
1.42 deraadt 698:
1.1 markus 699: creds = xmalloc(sizeof(*creds));
1.42 deraadt 700:
1.37 dugsong 701: problem = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm);
702: if (problem)
703: goto out;
1.42 deraadt 704:
1.37 dugsong 705: problem = krb_get_cred("krbtgt", prealm, prealm, creds);
706: if (problem)
707: goto out;
1.42 deraadt 708:
1.1 markus 709: if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) {
1.37 dugsong 710: problem = RD_AP_EXP;
711: goto out;
1.1 markus 712: }
1.37 dugsong 713: creds_to_radix(creds, (u_char *)buffer, sizeof(buffer));
1.42 deraadt 714:
1.1 markus 715: packet_start(SSH_CMSG_HAVE_KERBEROS_TGT);
1.33 markus 716: packet_put_cstring(buffer);
1.1 markus 717: packet_send();
718: packet_write_wait();
1.42 deraadt 719:
1.47 markus 720: type = packet_read();
1.42 deraadt 721:
1.37 dugsong 722: if (type == SSH_SMSG_SUCCESS)
723: debug("Kerberos v4 TGT forwarded (%s%s%s@%s).",
724: creds->pname, creds->pinst[0] ? "." : "",
725: creds->pinst, creds->realm);
726: else
727: debug("Kerberos v4 TGT rejected.");
1.42 deraadt 728:
1.37 dugsong 729: xfree(creds);
730: return;
1.42 deraadt 731:
1.37 dugsong 732: out:
733: debug("Kerberos v4 TGT passing failed: %s", krb_err_txt[problem]);
734: xfree(creds);
1.1 markus 735: }
736:
1.35 itojun 737: static void
1.1 markus 738: send_afs_tokens(void)
739: {
740: CREDENTIALS creds;
741: struct ViceIoctl parms;
742: struct ClearToken ct;
1.37 dugsong 743: int i, type, len;
1.1 markus 744: char buf[2048], *p, *server_cell;
745: char buffer[8192];
1.42 deraadt 746:
1.1 markus 747: /* Move over ktc_GetToken, here's something leaner. */
748: for (i = 0; i < 100; i++) { /* just in case */
749: parms.in = (char *) &i;
750: parms.in_size = sizeof(i);
751: parms.out = buf;
752: parms.out_size = sizeof(buf);
753: if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0)
754: break;
755: p = buf;
1.42 deraadt 756:
1.1 markus 757: /* Get secret token. */
1.13 markus 758: memcpy(&creds.ticket_st.length, p, sizeof(u_int));
1.1 markus 759: if (creds.ticket_st.length > MAX_KTXT_LEN)
760: break;
1.13 markus 761: p += sizeof(u_int);
1.1 markus 762: memcpy(creds.ticket_st.dat, p, creds.ticket_st.length);
763: p += creds.ticket_st.length;
1.42 deraadt 764:
1.1 markus 765: /* Get clear token. */
766: memcpy(&len, p, sizeof(len));
767: if (len != sizeof(struct ClearToken))
768: break;
769: p += sizeof(len);
770: memcpy(&ct, p, len);
771: p += len;
772: p += sizeof(len); /* primary flag */
773: server_cell = p;
1.42 deraadt 774:
1.1 markus 775: /* Flesh out our credentials. */
1.37 dugsong 776: strlcpy(creds.service, "afs", sizeof(creds.service));
1.1 markus 777: creds.instance[0] = '\0';
778: strlcpy(creds.realm, server_cell, REALM_SZ);
779: memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ);
780: creds.issue_date = ct.BeginTimestamp;
1.37 dugsong 781: creds.lifetime = krb_time_to_life(creds.issue_date,
782: ct.EndTimestamp);
1.1 markus 783: creds.kvno = ct.AuthHandle;
784: snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId);
785: creds.pinst[0] = '\0';
1.42 deraadt 786:
1.1 markus 787: /* Encode token, ship it off. */
1.37 dugsong 788: if (creds_to_radix(&creds, (u_char *)buffer,
789: sizeof(buffer)) <= 0)
1.1 markus 790: break;
791: packet_start(SSH_CMSG_HAVE_AFS_TOKEN);
1.33 markus 792: packet_put_cstring(buffer);
1.1 markus 793: packet_send();
794: packet_write_wait();
795:
796: /* Roger, Roger. Clearance, Clarence. What's your vector,
797: Victor? */
1.47 markus 798: type = packet_read();
1.42 deraadt 799:
1.1 markus 800: if (type == SSH_SMSG_FAILURE)
801: debug("AFS token for cell %s rejected.", server_cell);
802: else if (type != SSH_SMSG_SUCCESS)
803: packet_disconnect("Protocol error on AFS token response: %d", type);
804: }
805: }
806:
807: #endif /* AFS */
808:
809: /*
810: * Tries to authenticate with any string-based challenge/response system.
811: * Note that the client code is not tied to s/key or TIS.
812: */
1.35 itojun 813: static int
1.32 markus 814: try_challenge_response_authentication(void)
1.1 markus 815: {
816: int type, i;
1.13 markus 817: u_int clen;
1.12 markus 818: char prompt[1024];
1.1 markus 819: char *challenge, *response;
1.40 markus 820:
821: debug("Doing challenge response authentication.");
822:
1.12 markus 823: for (i = 0; i < options.number_of_password_prompts; i++) {
824: /* request a challenge */
825: packet_start(SSH_CMSG_AUTH_TIS);
826: packet_send();
827: packet_write_wait();
1.1 markus 828:
1.47 markus 829: type = packet_read();
1.12 markus 830: if (type != SSH_SMSG_FAILURE &&
831: type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
832: packet_disconnect("Protocol error: got %d in response "
1.20 markus 833: "to SSH_CMSG_AUTH_TIS", type);
1.12 markus 834: }
835: if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
1.20 markus 836: debug("No challenge.");
1.12 markus 837: return 0;
838: }
839: challenge = packet_get_string(&clen);
1.45 markus 840: packet_check_eom();
1.16 markus 841: snprintf(prompt, sizeof prompt, "%s%s", challenge,
1.42 deraadt 842: strchr(challenge, '\n') ? "" : "\nResponse: ");
1.12 markus 843: xfree(challenge);
1.1 markus 844: if (i != 0)
845: error("Permission denied, please try again.");
1.12 markus 846: if (options.cipher == SSH_CIPHER_NONE)
847: log("WARNING: Encryption is disabled! "
848: "Reponse will be transmitted in clear text.");
849: response = read_passphrase(prompt, 0);
850: if (strcmp(response, "") == 0) {
851: xfree(response);
852: break;
853: }
1.1 markus 854: packet_start(SSH_CMSG_AUTH_TIS_RESPONSE);
1.27 markus 855: ssh_put_password(response);
1.1 markus 856: memset(response, 0, strlen(response));
857: xfree(response);
858: packet_send();
859: packet_write_wait();
1.47 markus 860: type = packet_read();
1.1 markus 861: if (type == SSH_SMSG_SUCCESS)
862: return 1;
863: if (type != SSH_SMSG_FAILURE)
864: packet_disconnect("Protocol error: got %d in response "
1.20 markus 865: "to SSH_CMSG_AUTH_TIS_RESPONSE", type);
1.1 markus 866: }
867: /* failure */
868: return 0;
869: }
870:
871: /*
872: * Tries to authenticate with plain passwd authentication.
873: */
1.35 itojun 874: static int
1.1 markus 875: try_password_authentication(char *prompt)
876: {
1.47 markus 877: int type, i;
1.1 markus 878: char *password;
879:
880: debug("Doing password authentication.");
881: if (options.cipher == SSH_CIPHER_NONE)
882: log("WARNING: Encryption is disabled! Password will be transmitted in clear text.");
883: for (i = 0; i < options.number_of_password_prompts; i++) {
884: if (i != 0)
885: error("Permission denied, please try again.");
886: password = read_passphrase(prompt, 0);
887: packet_start(SSH_CMSG_AUTH_PASSWORD);
1.27 markus 888: ssh_put_password(password);
1.1 markus 889: memset(password, 0, strlen(password));
890: xfree(password);
891: packet_send();
892: packet_write_wait();
893:
1.47 markus 894: type = packet_read();
1.1 markus 895: if (type == SSH_SMSG_SUCCESS)
896: return 1;
897: if (type != SSH_SMSG_FAILURE)
898: packet_disconnect("Protocol error: got %d in response to passwd auth", type);
899: }
900: /* failure */
901: return 0;
902: }
903:
904: /*
905: * SSH1 key exchange
906: */
907: void
908: ssh_kex(char *host, struct sockaddr *hostaddr)
909: {
910: int i;
911: BIGNUM *key;
1.43 markus 912: Key *host_key, *server_key;
1.1 markus 913: int bits, rbits;
914: int ssh_cipher_default = SSH_CIPHER_3DES;
1.13 markus 915: u_char session_key[SSH_SESSION_KEY_LENGTH];
916: u_char cookie[8];
917: u_int supported_ciphers;
918: u_int server_flags, client_flags;
1.1 markus 919: u_int32_t rand = 0;
920:
921: debug("Waiting for server public key.");
922:
923: /* Wait for a public key packet from the server. */
1.47 markus 924: packet_read_expect(SSH_SMSG_PUBLIC_KEY);
1.1 markus 925:
926: /* Get cookie from the packet. */
927: for (i = 0; i < 8; i++)
928: cookie[i] = packet_get_char();
929:
930: /* Get the public key. */
1.43 markus 931: server_key = key_new(KEY_RSA1);
932: bits = packet_get_int();
1.46 markus 933: packet_get_bignum(server_key->rsa->e);
934: packet_get_bignum(server_key->rsa->n);
1.1 markus 935:
1.43 markus 936: rbits = BN_num_bits(server_key->rsa->n);
1.1 markus 937: if (bits != rbits) {
938: log("Warning: Server lies about size of server public key: "
939: "actual size is %d bits vs. announced %d.", rbits, bits);
940: log("Warning: This may be due to an old implementation of ssh.");
941: }
942: /* Get the host key. */
1.43 markus 943: host_key = key_new(KEY_RSA1);
944: bits = packet_get_int();
1.46 markus 945: packet_get_bignum(host_key->rsa->e);
946: packet_get_bignum(host_key->rsa->n);
1.1 markus 947:
1.43 markus 948: rbits = BN_num_bits(host_key->rsa->n);
1.1 markus 949: if (bits != rbits) {
950: log("Warning: Server lies about size of server host key: "
951: "actual size is %d bits vs. announced %d.", rbits, bits);
952: log("Warning: This may be due to an old implementation of ssh.");
953: }
954:
955: /* Get protocol flags. */
956: server_flags = packet_get_int();
957: packet_set_protocol_flags(server_flags);
958:
959: supported_ciphers = packet_get_int();
960: supported_authentications = packet_get_int();
1.45 markus 961: packet_check_eom();
1.1 markus 962:
963: debug("Received server public key (%d bits) and host key (%d bits).",
1.43 markus 964: BN_num_bits(server_key->rsa->n), BN_num_bits(host_key->rsa->n));
1.1 markus 965:
1.43 markus 966: if (verify_host_key(host, hostaddr, host_key) == -1)
1.41 markus 967: fatal("Host key verification failed.");
1.1 markus 968:
969: client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN;
970:
1.43 markus 971: compute_session_id(session_id, cookie, host_key->rsa->n, server_key->rsa->n);
1.1 markus 972:
973: /* Generate a session key. */
974: arc4random_stir();
975:
976: /*
977: * Generate an encryption key for the session. The key is a 256 bit
978: * random number, interpreted as a 32-byte key, with the least
979: * significant 8 bits being the first byte of the key.
980: */
981: for (i = 0; i < 32; i++) {
982: if (i % 4 == 0)
983: rand = arc4random();
984: session_key[i] = rand & 0xff;
985: rand >>= 8;
986: }
987:
988: /*
989: * According to the protocol spec, the first byte of the session key
990: * is the highest byte of the integer. The session key is xored with
991: * the first 16 bytes of the session id.
992: */
1.43 markus 993: if ((key = BN_new()) == NULL)
994: fatal("respond_to_rsa_challenge: BN_new failed");
1.1 markus 995: BN_set_word(key, 0);
996: for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
997: BN_lshift(key, key, 8);
998: if (i < 16)
999: BN_add_word(key, session_key[i] ^ session_id[i]);
1000: else
1001: BN_add_word(key, session_key[i]);
1002: }
1003:
1004: /*
1005: * Encrypt the integer using the public key and host key of the
1006: * server (key with smaller modulus first).
1007: */
1.43 markus 1008: if (BN_cmp(server_key->rsa->n, host_key->rsa->n) < 0) {
1.1 markus 1009: /* Public key has smaller modulus. */
1.43 markus 1010: if (BN_num_bits(host_key->rsa->n) <
1011: BN_num_bits(server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1012: fatal("respond_to_rsa_challenge: host_key %d < server_key %d + "
1.42 deraadt 1013: "SSH_KEY_BITS_RESERVED %d",
1.43 markus 1014: BN_num_bits(host_key->rsa->n),
1015: BN_num_bits(server_key->rsa->n),
1.42 deraadt 1016: SSH_KEY_BITS_RESERVED);
1.1 markus 1017: }
1.43 markus 1018: rsa_public_encrypt(key, key, server_key->rsa);
1019: rsa_public_encrypt(key, key, host_key->rsa);
1.1 markus 1020: } else {
1021: /* Host key has smaller modulus (or they are equal). */
1.43 markus 1022: if (BN_num_bits(server_key->rsa->n) <
1023: BN_num_bits(host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1024: fatal("respond_to_rsa_challenge: server_key %d < host_key %d + "
1.42 deraadt 1025: "SSH_KEY_BITS_RESERVED %d",
1.43 markus 1026: BN_num_bits(server_key->rsa->n),
1027: BN_num_bits(host_key->rsa->n),
1.42 deraadt 1028: SSH_KEY_BITS_RESERVED);
1.1 markus 1029: }
1.43 markus 1030: rsa_public_encrypt(key, key, host_key->rsa);
1031: rsa_public_encrypt(key, key, server_key->rsa);
1.1 markus 1032: }
1033:
1034: /* Destroy the public keys since we no longer need them. */
1.43 markus 1035: key_free(server_key);
1036: key_free(host_key);
1.1 markus 1037:
1.11 markus 1038: if (options.cipher == SSH_CIPHER_NOT_SET) {
1039: if (cipher_mask_ssh1(1) & supported_ciphers & (1 << ssh_cipher_default))
1040: options.cipher = ssh_cipher_default;
1041: } else if (options.cipher == SSH_CIPHER_ILLEGAL ||
1.10 markus 1042: !(cipher_mask_ssh1(1) & (1 << options.cipher))) {
1.3 markus 1043: log("No valid SSH1 cipher, using %.100s instead.",
1.7 markus 1044: cipher_name(ssh_cipher_default));
1045: options.cipher = ssh_cipher_default;
1.1 markus 1046: }
1047: /* Check that the selected cipher is supported. */
1048: if (!(supported_ciphers & (1 << options.cipher)))
1049: fatal("Selected cipher type %.100s not supported by server.",
1.42 deraadt 1050: cipher_name(options.cipher));
1.1 markus 1051:
1052: debug("Encryption type: %.100s", cipher_name(options.cipher));
1053:
1054: /* Send the encrypted session key to the server. */
1055: packet_start(SSH_CMSG_SESSION_KEY);
1056: packet_put_char(options.cipher);
1057:
1058: /* Send the cookie back to the server. */
1059: for (i = 0; i < 8; i++)
1060: packet_put_char(cookie[i]);
1061:
1062: /* Send and destroy the encrypted encryption key integer. */
1063: packet_put_bignum(key);
1064: BN_clear_free(key);
1065:
1066: /* Send protocol flags. */
1067: packet_put_int(client_flags);
1068:
1069: /* Send the packet now. */
1070: packet_send();
1071: packet_write_wait();
1072:
1073: debug("Sent encrypted session key.");
1074:
1075: /* Set the encryption key. */
1076: packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher);
1077:
1078: /* We will no longer need the session key here. Destroy any extra copies. */
1079: memset(session_key, 0, sizeof(session_key));
1080:
1081: /*
1082: * Expect a success message from the server. Note that this message
1083: * will be received in encrypted form.
1084: */
1.47 markus 1085: packet_read_expect(SSH_SMSG_SUCCESS);
1.1 markus 1086:
1087: debug("Received encrypted confirmation.");
1088: }
1089:
1090: /*
1091: * Authenticate user
1092: */
1093: void
1.30 markus 1094: ssh_userauth1(const char *local_user, const char *server_user, char *host,
1095: Key **keys, int nkeys)
1.1 markus 1096: {
1.37 dugsong 1097: #ifdef KRB5
1098: krb5_context context = NULL;
1099: krb5_auth_context auth_context = NULL;
1100: #endif
1.1 markus 1101: int i, type;
1.42 deraadt 1102:
1.1 markus 1103: if (supported_authentications == 0)
1.30 markus 1104: fatal("ssh_userauth1: server supports no auth methods");
1.1 markus 1105:
1106: /* Send the name of the user to log in as on the server. */
1107: packet_start(SSH_CMSG_USER);
1.33 markus 1108: packet_put_cstring(server_user);
1.1 markus 1109: packet_send();
1110: packet_write_wait();
1111:
1112: /*
1113: * The server should respond with success if no authentication is
1114: * needed (the user has no password). Otherwise the server responds
1115: * with failure.
1116: */
1.47 markus 1117: type = packet_read();
1.1 markus 1118:
1119: /* check whether the connection was accepted without authentication. */
1120: if (type == SSH_SMSG_SUCCESS)
1.37 dugsong 1121: goto success;
1.1 markus 1122: if (type != SSH_SMSG_FAILURE)
1.37 dugsong 1123: packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", type);
1.42 deraadt 1124:
1.37 dugsong 1125: #ifdef KRB5
1126: if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) &&
1.42 deraadt 1127: options.kerberos_authentication) {
1.37 dugsong 1128: debug("Trying Kerberos v5 authentication.");
1.42 deraadt 1129:
1.37 dugsong 1130: if (try_krb5_authentication(&context, &auth_context)) {
1.47 markus 1131: type = packet_read();
1.37 dugsong 1132: if (type == SSH_SMSG_SUCCESS)
1133: goto success;
1134: if (type != SSH_SMSG_FAILURE)
1135: packet_disconnect("Protocol error: got %d in response to Kerberos v5 auth", type);
1136: }
1.1 markus 1137: }
1.37 dugsong 1138: #endif /* KRB5 */
1.42 deraadt 1139:
1.1 markus 1140: #ifdef KRB4
1141: if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) &&
1142: options.kerberos_authentication) {
1.37 dugsong 1143: debug("Trying Kerberos v4 authentication.");
1.42 deraadt 1144:
1.37 dugsong 1145: if (try_krb4_authentication()) {
1.47 markus 1146: type = packet_read();
1.1 markus 1147: if (type == SSH_SMSG_SUCCESS)
1.37 dugsong 1148: goto success;
1.1 markus 1149: if (type != SSH_SMSG_FAILURE)
1.37 dugsong 1150: packet_disconnect("Protocol error: got %d in response to Kerberos v4 auth", type);
1.1 markus 1151: }
1152: }
1153: #endif /* KRB4 */
1.42 deraadt 1154:
1.1 markus 1155: /*
1156: * Use rhosts authentication if running in privileged socket and we
1157: * do not wish to remain anonymous.
1158: */
1159: if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) &&
1160: options.rhosts_authentication) {
1161: debug("Trying rhosts authentication.");
1162: packet_start(SSH_CMSG_AUTH_RHOSTS);
1.33 markus 1163: packet_put_cstring(local_user);
1.1 markus 1164: packet_send();
1165: packet_write_wait();
1166:
1167: /* The server should respond with success or failure. */
1.47 markus 1168: type = packet_read();
1.1 markus 1169: if (type == SSH_SMSG_SUCCESS)
1.37 dugsong 1170: goto success;
1.1 markus 1171: if (type != SSH_SMSG_FAILURE)
1172: packet_disconnect("Protocol error: got %d in response to rhosts auth",
1173: type);
1174: }
1175: /*
1176: * Try .rhosts or /etc/hosts.equiv authentication with RSA host
1177: * authentication.
1178: */
1179: if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) &&
1.30 markus 1180: options.rhosts_rsa_authentication) {
1181: for (i = 0; i < nkeys; i++) {
1.31 markus 1182: if (keys[i] != NULL && keys[i]->type == KEY_RSA1 &&
1.30 markus 1183: try_rhosts_rsa_authentication(local_user, keys[i]))
1.37 dugsong 1184: goto success;
1.30 markus 1185: }
1.1 markus 1186: }
1187: /* Try RSA authentication if the server supports it. */
1188: if ((supported_authentications & (1 << SSH_AUTH_RSA)) &&
1189: options.rsa_authentication) {
1190: /*
1191: * Try RSA authentication using the authentication agent. The
1192: * agent is tried first because no passphrase is needed for
1193: * it, whereas identity files may require passphrases.
1194: */
1195: if (try_agent_authentication())
1.37 dugsong 1196: goto success;
1.1 markus 1197:
1198: /* Try RSA authentication for each identity. */
1199: for (i = 0; i < options.num_identity_files; i++)
1.28 markus 1200: if (options.identity_keys[i] != NULL &&
1201: options.identity_keys[i]->type == KEY_RSA1 &&
1.38 markus 1202: try_rsa_authentication(i))
1.37 dugsong 1203: goto success;
1.1 markus 1204: }
1.20 markus 1205: /* Try challenge response authentication if the server supports it. */
1.1 markus 1206: if ((supported_authentications & (1 << SSH_AUTH_TIS)) &&
1.32 markus 1207: options.challenge_response_authentication && !options.batch_mode) {
1208: if (try_challenge_response_authentication())
1.37 dugsong 1209: goto success;
1.1 markus 1210: }
1211: /* Try password authentication if the server supports it. */
1212: if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) &&
1213: options.password_authentication && !options.batch_mode) {
1214: char prompt[80];
1215:
1.23 itojun 1216: snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1.1 markus 1217: server_user, host);
1218: if (try_password_authentication(prompt))
1.37 dugsong 1219: goto success;
1.1 markus 1220: }
1221: /* All authentication methods have failed. Exit with an error message. */
1222: fatal("Permission denied.");
1223: /* NOTREACHED */
1.37 dugsong 1224:
1225: success:
1226: #ifdef KRB5
1227: /* Try Kerberos v5 TGT passing. */
1228: if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&
1229: options.kerberos_tgt_passing && context && auth_context) {
1230: if (options.cipher == SSH_CIPHER_NONE)
1231: log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");
1232: send_krb5_tgt(context, auth_context);
1233: }
1234: if (auth_context)
1235: krb5_auth_con_free(context, auth_context);
1236: if (context)
1237: krb5_free_context(context);
1238: #endif
1.42 deraadt 1239:
1.37 dugsong 1240: #ifdef AFS
1241: /* Try Kerberos v4 TGT passing if the server supports it. */
1242: if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&
1243: options.kerberos_tgt_passing) {
1244: if (options.cipher == SSH_CIPHER_NONE)
1245: log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");
1246: send_krb4_tgt();
1247: }
1248: /* Try AFS token passing if the server supports it. */
1249: if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) &&
1250: options.afs_token_passing && k_hasafs()) {
1251: if (options.cipher == SSH_CIPHER_NONE)
1252: log("WARNING: Encryption is disabled! Token will be transmitted in the clear!");
1253: send_afs_tokens();
1254: }
1255: #endif /* AFS */
1.39 stevesk 1256:
1257: return; /* need statement after label */
1.1 markus 1258: }
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