Annotation of src/usr.bin/ssh/sshconnect1.c, Revision 1.43
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"
1.43 ! markus 16: RCSID("$OpenBSD: sshconnect1.c,v 1.42 2001/12/19 07:18:56 deraadt 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: int plen, clen;
71: Key *key;
72: BIGNUM *challenge;
1.1 markus 73:
74: /* Get connection to the agent. */
75: auth = ssh_get_authentication_connection();
76: if (!auth)
77: return 0;
78:
1.43 ! markus 79: if ((challenge = BN_new()) == NULL)
! 80: fatal("try_agent_authentication: BN_new failed");
1.1 markus 81: /* Loop through identities served by the agent. */
1.5 markus 82: for (key = ssh_get_first_identity(auth, &comment, 1);
1.42 deraadt 83: key != NULL;
84: key = ssh_get_next_identity(auth, &comment, 1)) {
1.1 markus 85:
86: /* Try this identity. */
87: debug("Trying RSA authentication via agent with '%.100s'", comment);
88: xfree(comment);
89:
90: /* Tell the server that we are willing to authenticate using this key. */
91: packet_start(SSH_CMSG_AUTH_RSA);
1.5 markus 92: packet_put_bignum(key->rsa->n);
1.1 markus 93: packet_send();
94: packet_write_wait();
95:
96: /* Wait for server's response. */
97: type = packet_read(&plen);
98:
99: /* The server sends failure if it doesn\'t like our key or
100: does not support RSA authentication. */
101: if (type == SSH_SMSG_FAILURE) {
102: debug("Server refused our key.");
1.5 markus 103: key_free(key);
1.1 markus 104: continue;
105: }
106: /* Otherwise it should have sent a challenge. */
107: if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
108: packet_disconnect("Protocol error during RSA authentication: %d",
109: type);
110:
111: packet_get_bignum(challenge, &clen);
112:
113: packet_integrity_check(plen, clen, type);
114:
115: debug("Received RSA challenge from server.");
116:
117: /* Ask the agent to decrypt the challenge. */
1.5 markus 118: if (!ssh_decrypt_challenge(auth, key, challenge, session_id, 1, response)) {
119: /*
120: * The agent failed to authenticate this identifier
121: * although it advertised it supports this. Just
122: * return a wrong value.
123: */
1.1 markus 124: log("Authentication agent failed to decrypt challenge.");
125: memset(response, 0, sizeof(response));
126: }
1.5 markus 127: key_free(key);
1.1 markus 128: debug("Sending response to RSA challenge.");
129:
130: /* Send the decrypted challenge back to the server. */
131: packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
132: for (i = 0; i < 16; i++)
133: packet_put_char(response[i]);
134: packet_send();
135: packet_write_wait();
136:
137: /* Wait for response from the server. */
138: type = packet_read(&plen);
139:
140: /* The server returns success if it accepted the authentication. */
141: if (type == SSH_SMSG_SUCCESS) {
1.14 markus 142: ssh_close_authentication_connection(auth);
1.5 markus 143: BN_clear_free(challenge);
1.1 markus 144: debug("RSA authentication accepted by server.");
145: return 1;
146: }
147: /* Otherwise it should return failure. */
148: if (type != SSH_SMSG_FAILURE)
149: packet_disconnect("Protocol error waiting RSA auth response: %d",
150: type);
151: }
1.14 markus 152: ssh_close_authentication_connection(auth);
1.1 markus 153: BN_clear_free(challenge);
154: debug("RSA authentication using agent refused.");
155: return 0;
156: }
157:
158: /*
159: * Computes the proper response to a RSA challenge, and sends the response to
160: * the server.
161: */
1.35 itojun 162: static void
1.1 markus 163: respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv)
164: {
1.13 markus 165: u_char buf[32], response[16];
1.1 markus 166: MD5_CTX md;
167: int i, len;
168:
169: /* Decrypt the challenge using the private key. */
1.21 markus 170: /* XXX think about Bleichenbacher, too */
171: if (rsa_private_decrypt(challenge, challenge, prv) <= 0)
172: packet_disconnect(
173: "respond_to_rsa_challenge: rsa_private_decrypt failed");
1.1 markus 174:
175: /* Compute the response. */
176: /* The response is MD5 of decrypted challenge plus session id. */
177: len = BN_num_bytes(challenge);
178: if (len <= 0 || len > sizeof(buf))
1.21 markus 179: packet_disconnect(
180: "respond_to_rsa_challenge: bad challenge length %d", len);
1.1 markus 181:
182: memset(buf, 0, sizeof(buf));
183: BN_bn2bin(challenge, buf + sizeof(buf) - len);
184: MD5_Init(&md);
185: MD5_Update(&md, buf, 32);
186: MD5_Update(&md, session_id, 16);
187: MD5_Final(response, &md);
188:
189: debug("Sending response to host key RSA challenge.");
190:
191: /* Send the response back to the server. */
192: packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
193: for (i = 0; i < 16; i++)
194: packet_put_char(response[i]);
195: packet_send();
196: packet_write_wait();
197:
198: memset(buf, 0, sizeof(buf));
199: memset(response, 0, sizeof(response));
200: memset(&md, 0, sizeof(md));
201: }
202:
203: /*
204: * Checks if the user has authentication file, and if so, tries to authenticate
205: * the user using it.
206: */
1.35 itojun 207: static int
1.38 markus 208: try_rsa_authentication(int idx)
1.1 markus 209: {
210: BIGNUM *challenge;
1.36 markus 211: Key *public, *private;
1.38 markus 212: char buf[300], *passphrase, *comment, *authfile;
1.36 markus 213: int i, type, quit, plen, clen;
1.1 markus 214:
1.38 markus 215: public = options.identity_keys[idx];
216: authfile = options.identity_files[idx];
217: comment = xstrdup(authfile);
218:
1.1 markus 219: debug("Trying RSA authentication with key '%.100s'", comment);
220:
221: /* Tell the server that we are willing to authenticate using this key. */
222: packet_start(SSH_CMSG_AUTH_RSA);
223: packet_put_bignum(public->rsa->n);
224: packet_send();
225: packet_write_wait();
226:
227: /* Wait for server's response. */
228: type = packet_read(&plen);
229:
230: /*
231: * The server responds with failure if it doesn\'t like our key or
232: * doesn\'t support RSA authentication.
233: */
234: if (type == SSH_SMSG_FAILURE) {
235: debug("Server refused our key.");
236: xfree(comment);
237: return 0;
238: }
239: /* Otherwise, the server should respond with a challenge. */
240: if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
241: packet_disconnect("Protocol error during RSA authentication: %d", type);
242:
243: /* Get the challenge from the packet. */
1.43 ! markus 244: if ((challenge = BN_new()) == NULL)
! 245: fatal("try_rsa_authentication: BN_new failed");
1.1 markus 246: packet_get_bignum(challenge, &clen);
247:
248: packet_integrity_check(plen, clen, type);
249:
250: debug("Received RSA challenge from server.");
251:
252: /*
1.38 markus 253: * If the key is not stored in external hardware, we have to
254: * load the private key. Try first with empty passphrase; if it
1.1 markus 255: * fails, ask for a passphrase.
256: */
1.38 markus 257: if (public->flags && KEY_FLAG_EXT)
258: private = public;
259: else
260: private = key_load_private_type(KEY_RSA1, authfile, "", NULL);
1.36 markus 261: if (private == NULL && !options.batch_mode) {
262: snprintf(buf, sizeof(buf),
263: "Enter passphrase for RSA key '%.100s': ", comment);
264: for (i = 0; i < options.number_of_password_prompts; i++) {
1.1 markus 265: passphrase = read_passphrase(buf, 0);
1.36 markus 266: if (strcmp(passphrase, "") != 0) {
267: private = key_load_private_type(KEY_RSA1,
268: authfile, passphrase, NULL);
269: quit = 0;
270: } else {
271: debug2("no passphrase given, try next key");
272: quit = 1;
273: }
1.1 markus 274: memset(passphrase, 0, strlen(passphrase));
275: xfree(passphrase);
1.36 markus 276: if (private != NULL || quit)
277: break;
278: debug2("bad passphrase given, try again...");
1.1 markus 279: }
280: }
281: /* We no longer need the comment. */
282: xfree(comment);
1.36 markus 283:
284: if (private == NULL) {
285: if (!options.batch_mode)
286: error("Bad passphrase.");
287:
288: /* Send a dummy response packet to avoid protocol error. */
289: packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
290: for (i = 0; i < 16; i++)
291: packet_put_char(0);
292: packet_send();
293: packet_write_wait();
294:
295: /* Expect the server to reject it... */
296: packet_read_expect(&plen, SSH_SMSG_FAILURE);
297: BN_clear_free(challenge);
298: return 0;
299: }
1.1 markus 300:
301: /* Compute and send a response to the challenge. */
302: respond_to_rsa_challenge(challenge, private->rsa);
303:
1.38 markus 304: /* Destroy the private key unless it in external hardware. */
305: if (!(private->flags & KEY_FLAG_EXT))
306: key_free(private);
1.1 markus 307:
308: /* We no longer need the challenge. */
309: BN_clear_free(challenge);
310:
311: /* Wait for response from the server. */
312: type = packet_read(&plen);
313: if (type == SSH_SMSG_SUCCESS) {
314: debug("RSA authentication accepted by server.");
315: return 1;
316: }
317: if (type != SSH_SMSG_FAILURE)
318: packet_disconnect("Protocol error waiting RSA auth response: %d", type);
319: debug("RSA authentication refused.");
320: return 0;
321: }
322:
323: /*
324: * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv
325: * authentication and RSA host authentication.
326: */
1.35 itojun 327: static int
1.29 markus 328: try_rhosts_rsa_authentication(const char *local_user, Key * host_key)
1.1 markus 329: {
330: int type;
331: BIGNUM *challenge;
332: int plen, clen;
333:
334: debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication.");
335:
336: /* Tell the server that we are willing to authenticate using this key. */
337: packet_start(SSH_CMSG_AUTH_RHOSTS_RSA);
1.33 markus 338: packet_put_cstring(local_user);
1.29 markus 339: packet_put_int(BN_num_bits(host_key->rsa->n));
340: packet_put_bignum(host_key->rsa->e);
341: packet_put_bignum(host_key->rsa->n);
1.1 markus 342: packet_send();
343: packet_write_wait();
344:
345: /* Wait for server's response. */
346: type = packet_read(&plen);
347:
348: /* The server responds with failure if it doesn't admit our
349: .rhosts authentication or doesn't know our host key. */
350: if (type == SSH_SMSG_FAILURE) {
351: debug("Server refused our rhosts authentication or host key.");
352: return 0;
353: }
354: /* Otherwise, the server should respond with a challenge. */
355: if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
356: packet_disconnect("Protocol error during RSA authentication: %d", type);
357:
358: /* Get the challenge from the packet. */
1.43 ! markus 359: if ((challenge = BN_new()) == NULL)
! 360: fatal("try_rhosts_rsa_authentication: BN_new failed");
1.1 markus 361: packet_get_bignum(challenge, &clen);
362:
363: packet_integrity_check(plen, clen, type);
364:
365: debug("Received RSA challenge for host key from server.");
366:
367: /* Compute a response to the challenge. */
1.29 markus 368: respond_to_rsa_challenge(challenge, host_key->rsa);
1.1 markus 369:
370: /* We no longer need the challenge. */
371: BN_clear_free(challenge);
372:
373: /* Wait for response from the server. */
374: type = packet_read(&plen);
375: if (type == SSH_SMSG_SUCCESS) {
376: debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server.");
377: return 1;
378: }
379: if (type != SSH_SMSG_FAILURE)
380: packet_disconnect("Protocol error waiting RSA auth response: %d", type);
381: debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused.");
382: return 0;
383: }
384:
385: #ifdef KRB4
1.35 itojun 386: static int
1.37 dugsong 387: try_krb4_authentication(void)
1.1 markus 388: {
389: KTEXT_ST auth; /* Kerberos data */
390: char *reply;
391: char inst[INST_SZ];
392: char *realm;
393: CREDENTIALS cred;
394: int r, type, plen;
395: socklen_t slen;
396: Key_schedule schedule;
397: u_long checksum, cksum;
398: MSG_DAT msg_data;
399: struct sockaddr_in local, foreign;
400: struct stat st;
401:
402: /* Don't do anything if we don't have any tickets. */
403: if (stat(tkt_string(), &st) < 0)
404: return 0;
1.42 deraadt 405:
1.37 dugsong 406: strlcpy(inst, (char *)krb_get_phost(get_canonical_hostname(1)),
407: INST_SZ);
1.42 deraadt 408:
1.37 dugsong 409: realm = (char *)krb_realmofhost(get_canonical_hostname(1));
1.1 markus 410: if (!realm) {
1.37 dugsong 411: debug("Kerberos v4: no realm for %s", get_canonical_hostname(1));
1.1 markus 412: return 0;
413: }
414: /* This can really be anything. */
1.37 dugsong 415: checksum = (u_long)getpid();
1.42 deraadt 416:
1.1 markus 417: r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum);
418: if (r != KSUCCESS) {
1.37 dugsong 419: debug("Kerberos v4 krb_mk_req failed: %s", krb_err_txt[r]);
1.1 markus 420: return 0;
421: }
422: /* Get session key to decrypt the server's reply with. */
423: r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred);
424: if (r != KSUCCESS) {
425: debug("get_cred failed: %s", krb_err_txt[r]);
426: return 0;
427: }
428: des_key_sched((des_cblock *) cred.session, schedule);
1.42 deraadt 429:
1.1 markus 430: /* Send authentication info to server. */
431: packet_start(SSH_CMSG_AUTH_KERBEROS);
432: packet_put_string((char *) auth.dat, auth.length);
433: packet_send();
434: packet_write_wait();
1.42 deraadt 435:
1.1 markus 436: /* Zero the buffer. */
437: (void) memset(auth.dat, 0, MAX_KTXT_LEN);
1.42 deraadt 438:
1.1 markus 439: slen = sizeof(local);
440: memset(&local, 0, sizeof(local));
441: if (getsockname(packet_get_connection_in(),
1.37 dugsong 442: (struct sockaddr *)&local, &slen) < 0)
1.1 markus 443: debug("getsockname failed: %s", strerror(errno));
1.42 deraadt 444:
1.1 markus 445: slen = sizeof(foreign);
446: memset(&foreign, 0, sizeof(foreign));
447: if (getpeername(packet_get_connection_in(),
1.37 dugsong 448: (struct sockaddr *)&foreign, &slen) < 0) {
1.1 markus 449: debug("getpeername failed: %s", strerror(errno));
450: fatal_cleanup();
451: }
452: /* Get server reply. */
453: type = packet_read(&plen);
454: switch (type) {
455: case SSH_SMSG_FAILURE:
456: /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */
1.37 dugsong 457: debug("Kerberos v4 authentication failed.");
1.1 markus 458: return 0;
459: break;
1.42 deraadt 460:
1.1 markus 461: case SSH_SMSG_AUTH_KERBEROS_RESPONSE:
462: /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */
1.37 dugsong 463: debug("Kerberos v4 authentication accepted.");
1.42 deraadt 464:
1.1 markus 465: /* Get server's response. */
1.13 markus 466: reply = packet_get_string((u_int *) &auth.length);
1.1 markus 467: memcpy(auth.dat, reply, auth.length);
468: xfree(reply);
1.42 deraadt 469:
1.1 markus 470: packet_integrity_check(plen, 4 + auth.length, type);
1.42 deraadt 471:
1.1 markus 472: /*
473: * If his response isn't properly encrypted with the session
474: * key, and the decrypted checksum fails to match, he's
475: * bogus. Bail out.
476: */
477: r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session,
1.37 dugsong 478: &foreign, &local, &msg_data);
1.1 markus 479: if (r != KSUCCESS) {
1.37 dugsong 480: debug("Kerberos v4 krb_rd_priv failed: %s",
481: krb_err_txt[r]);
482: packet_disconnect("Kerberos v4 challenge failed!");
1.1 markus 483: }
484: /* Fetch the (incremented) checksum that we supplied in the request. */
1.37 dugsong 485: memcpy((char *)&cksum, (char *)msg_data.app_data,
486: sizeof(cksum));
1.1 markus 487: cksum = ntohl(cksum);
1.42 deraadt 488:
1.1 markus 489: /* If it matches, we're golden. */
490: if (cksum == checksum + 1) {
1.37 dugsong 491: debug("Kerberos v4 challenge successful.");
1.1 markus 492: return 1;
493: } else
1.37 dugsong 494: packet_disconnect("Kerberos v4 challenge failed!");
1.1 markus 495: break;
1.42 deraadt 496:
1.1 markus 497: default:
1.37 dugsong 498: packet_disconnect("Protocol error on Kerberos v4 response: %d", type);
1.1 markus 499: }
500: return 0;
501: }
502:
503: #endif /* KRB4 */
504:
1.37 dugsong 505: #ifdef KRB5
506: static int
507: try_krb5_authentication(krb5_context *context, krb5_auth_context *auth_context)
508: {
509: krb5_error_code problem;
510: const char *tkfile;
511: struct stat buf;
512: krb5_ccache ccache = NULL;
513: const char *remotehost;
514: krb5_data ap;
515: int type, payload_len;
516: krb5_ap_rep_enc_part *reply = NULL;
517: int ret;
1.42 deraadt 518:
1.37 dugsong 519: memset(&ap, 0, sizeof(ap));
1.42 deraadt 520:
1.37 dugsong 521: problem = krb5_init_context(context);
522: if (problem) {
523: debug("Kerberos v5: krb5_init_context failed");
524: ret = 0;
525: goto out;
526: }
1.42 deraadt 527:
1.37 dugsong 528: tkfile = krb5_cc_default_name(*context);
529: if (strncmp(tkfile, "FILE:", 5) == 0)
530: tkfile += 5;
1.42 deraadt 531:
1.37 dugsong 532: if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) {
533: debug("Kerberos v5: could not get default ccache (permission denied).");
534: ret = 0;
535: goto out;
536: }
1.42 deraadt 537:
1.37 dugsong 538: problem = krb5_cc_default(*context, &ccache);
539: if (problem) {
540: debug("Kerberos v5: krb5_cc_default failed: %s",
541: krb5_get_err_text(*context, problem));
542: ret = 0;
543: goto out;
544: }
1.42 deraadt 545:
1.37 dugsong 546: remotehost = get_canonical_hostname(1);
1.42 deraadt 547:
1.37 dugsong 548: problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED,
549: "host", remotehost, NULL, ccache, &ap);
550: if (problem) {
551: debug("Kerberos v5: krb5_mk_req failed: %s",
552: krb5_get_err_text(*context, problem));
553: ret = 0;
554: goto out;
555: }
1.42 deraadt 556:
1.37 dugsong 557: packet_start(SSH_CMSG_AUTH_KERBEROS);
558: packet_put_string((char *) ap.data, ap.length);
559: packet_send();
560: packet_write_wait();
1.42 deraadt 561:
1.37 dugsong 562: xfree(ap.data);
563: ap.length = 0;
1.42 deraadt 564:
1.37 dugsong 565: type = packet_read(&payload_len);
566: switch (type) {
1.42 deraadt 567: case SSH_SMSG_FAILURE:
568: /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */
569: debug("Kerberos v5 authentication failed.");
570: ret = 0;
571: break;
572:
1.37 dugsong 573: case SSH_SMSG_AUTH_KERBEROS_RESPONSE:
1.42 deraadt 574: /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */
575: debug("Kerberos v5 authentication accepted.");
576:
577: /* Get server's response. */
578: ap.data = packet_get_string((unsigned int *) &ap.length);
579:
580: packet_integrity_check(payload_len, 4 + ap.length, type);
581: /* XXX je to dobre? */
582:
583: problem = krb5_rd_rep(*context, *auth_context, &ap, &reply);
584: if (problem) {
1.37 dugsong 585: ret = 0;
586: }
587: ret = 1;
588: break;
1.42 deraadt 589:
1.37 dugsong 590: default:
591: packet_disconnect("Protocol error on Kerberos v5 response: %d",
592: type);
593: ret = 0;
594: break;
1.42 deraadt 595:
1.37 dugsong 596: }
1.42 deraadt 597:
1.37 dugsong 598: out:
599: if (ccache != NULL)
600: krb5_cc_close(*context, ccache);
601: if (reply != NULL)
602: krb5_free_ap_rep_enc_part(*context, reply);
603: if (ap.length > 0)
604: krb5_data_free(&ap);
1.42 deraadt 605:
1.37 dugsong 606: return (ret);
607: }
608:
609: static void
610: send_krb5_tgt(krb5_context context, krb5_auth_context auth_context)
611: {
612: int fd, type, payload_len;
613: krb5_error_code problem;
614: krb5_data outbuf;
615: krb5_ccache ccache = NULL;
616: krb5_creds creds;
617: krb5_kdc_flags flags;
618: const char *remotehost;
1.42 deraadt 619:
1.37 dugsong 620: memset(&creds, 0, sizeof(creds));
621: memset(&outbuf, 0, sizeof(outbuf));
1.42 deraadt 622:
1.37 dugsong 623: fd = packet_get_connection_in();
1.42 deraadt 624:
1.37 dugsong 625: problem = krb5_auth_con_setaddrs_from_fd(context, auth_context, &fd);
626: if (problem)
627: goto out;
1.42 deraadt 628:
1.37 dugsong 629: problem = krb5_cc_default(context, &ccache);
630: if (problem)
631: goto out;
1.42 deraadt 632:
1.37 dugsong 633: problem = krb5_cc_get_principal(context, ccache, &creds.client);
634: if (problem)
635: goto out;
1.42 deraadt 636:
1.37 dugsong 637: problem = krb5_build_principal(context, &creds.server,
638: strlen(creds.client->realm), creds.client->realm,
639: "krbtgt", creds.client->realm, NULL);
640: if (problem)
641: goto out;
1.42 deraadt 642:
1.37 dugsong 643: creds.times.endtime = 0;
1.42 deraadt 644:
1.37 dugsong 645: flags.i = 0;
646: flags.b.forwarded = 1;
647: flags.b.forwardable = krb5_config_get_bool(context, NULL,
648: "libdefaults", "forwardable", NULL);
1.42 deraadt 649:
1.37 dugsong 650: remotehost = get_canonical_hostname(1);
1.42 deraadt 651:
1.37 dugsong 652: problem = krb5_get_forwarded_creds(context, auth_context,
653: ccache, flags.i, remotehost, &creds, &outbuf);
654: if (problem)
655: goto out;
1.42 deraadt 656:
1.37 dugsong 657: packet_start(SSH_CMSG_HAVE_KERBEROS_TGT);
658: packet_put_string((char *)outbuf.data, outbuf.length);
659: packet_send();
660: packet_write_wait();
1.42 deraadt 661:
1.37 dugsong 662: type = packet_read(&payload_len);
1.42 deraadt 663:
1.37 dugsong 664: if (type == SSH_SMSG_SUCCESS) {
665: char *pname;
1.42 deraadt 666:
1.37 dugsong 667: krb5_unparse_name(context, creds.client, &pname);
668: debug("Kerberos v5 TGT forwarded (%s).", pname);
669: xfree(pname);
670: } else
671: debug("Kerberos v5 TGT forwarding failed.");
1.42 deraadt 672:
1.37 dugsong 673: return;
1.42 deraadt 674:
1.37 dugsong 675: out:
676: if (problem)
677: debug("Kerberos v5 TGT forwarding failed: %s",
678: krb5_get_err_text(context, problem));
679: if (creds.client)
680: krb5_free_principal(context, creds.client);
681: if (creds.server)
682: krb5_free_principal(context, creds.server);
683: if (ccache)
684: krb5_cc_close(context, ccache);
685: if (outbuf.data)
686: xfree(outbuf.data);
687: }
688: #endif /* KRB5 */
689:
1.1 markus 690: #ifdef AFS
1.37 dugsong 691: static void
692: send_krb4_tgt(void)
1.1 markus 693: {
694: CREDENTIALS *creds;
695: struct stat st;
1.37 dugsong 696: char buffer[4096], pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ];
697: int problem, type, len;
1.42 deraadt 698:
1.1 markus 699: /* Don't do anything if we don't have any tickets. */
700: if (stat(tkt_string(), &st) < 0)
1.37 dugsong 701: return;
1.42 deraadt 702:
1.1 markus 703: creds = xmalloc(sizeof(*creds));
1.42 deraadt 704:
1.37 dugsong 705: problem = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm);
706: if (problem)
707: goto out;
1.42 deraadt 708:
1.37 dugsong 709: problem = krb_get_cred("krbtgt", prealm, prealm, creds);
710: if (problem)
711: goto out;
1.42 deraadt 712:
1.1 markus 713: if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) {
1.37 dugsong 714: problem = RD_AP_EXP;
715: goto out;
1.1 markus 716: }
1.37 dugsong 717: creds_to_radix(creds, (u_char *)buffer, sizeof(buffer));
1.42 deraadt 718:
1.1 markus 719: packet_start(SSH_CMSG_HAVE_KERBEROS_TGT);
1.33 markus 720: packet_put_cstring(buffer);
1.1 markus 721: packet_send();
722: packet_write_wait();
1.42 deraadt 723:
1.37 dugsong 724: type = packet_read(&len);
1.42 deraadt 725:
1.37 dugsong 726: if (type == SSH_SMSG_SUCCESS)
727: debug("Kerberos v4 TGT forwarded (%s%s%s@%s).",
728: creds->pname, creds->pinst[0] ? "." : "",
729: creds->pinst, creds->realm);
730: else
731: debug("Kerberos v4 TGT rejected.");
1.42 deraadt 732:
1.37 dugsong 733: xfree(creds);
734: return;
1.42 deraadt 735:
1.37 dugsong 736: out:
737: debug("Kerberos v4 TGT passing failed: %s", krb_err_txt[problem]);
738: xfree(creds);
1.1 markus 739: }
740:
1.35 itojun 741: static void
1.1 markus 742: send_afs_tokens(void)
743: {
744: CREDENTIALS creds;
745: struct ViceIoctl parms;
746: struct ClearToken ct;
1.37 dugsong 747: int i, type, len;
1.1 markus 748: char buf[2048], *p, *server_cell;
749: char buffer[8192];
1.42 deraadt 750:
1.1 markus 751: /* Move over ktc_GetToken, here's something leaner. */
752: for (i = 0; i < 100; i++) { /* just in case */
753: parms.in = (char *) &i;
754: parms.in_size = sizeof(i);
755: parms.out = buf;
756: parms.out_size = sizeof(buf);
757: if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0)
758: break;
759: p = buf;
1.42 deraadt 760:
1.1 markus 761: /* Get secret token. */
1.13 markus 762: memcpy(&creds.ticket_st.length, p, sizeof(u_int));
1.1 markus 763: if (creds.ticket_st.length > MAX_KTXT_LEN)
764: break;
1.13 markus 765: p += sizeof(u_int);
1.1 markus 766: memcpy(creds.ticket_st.dat, p, creds.ticket_st.length);
767: p += creds.ticket_st.length;
1.42 deraadt 768:
1.1 markus 769: /* Get clear token. */
770: memcpy(&len, p, sizeof(len));
771: if (len != sizeof(struct ClearToken))
772: break;
773: p += sizeof(len);
774: memcpy(&ct, p, len);
775: p += len;
776: p += sizeof(len); /* primary flag */
777: server_cell = p;
1.42 deraadt 778:
1.1 markus 779: /* Flesh out our credentials. */
1.37 dugsong 780: strlcpy(creds.service, "afs", sizeof(creds.service));
1.1 markus 781: creds.instance[0] = '\0';
782: strlcpy(creds.realm, server_cell, REALM_SZ);
783: memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ);
784: creds.issue_date = ct.BeginTimestamp;
1.37 dugsong 785: creds.lifetime = krb_time_to_life(creds.issue_date,
786: ct.EndTimestamp);
1.1 markus 787: creds.kvno = ct.AuthHandle;
788: snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId);
789: creds.pinst[0] = '\0';
1.42 deraadt 790:
1.1 markus 791: /* Encode token, ship it off. */
1.37 dugsong 792: if (creds_to_radix(&creds, (u_char *)buffer,
793: sizeof(buffer)) <= 0)
1.1 markus 794: break;
795: packet_start(SSH_CMSG_HAVE_AFS_TOKEN);
1.33 markus 796: packet_put_cstring(buffer);
1.1 markus 797: packet_send();
798: packet_write_wait();
799:
800: /* Roger, Roger. Clearance, Clarence. What's your vector,
801: Victor? */
1.37 dugsong 802: type = packet_read(&len);
1.42 deraadt 803:
1.1 markus 804: if (type == SSH_SMSG_FAILURE)
805: debug("AFS token for cell %s rejected.", server_cell);
806: else if (type != SSH_SMSG_SUCCESS)
807: packet_disconnect("Protocol error on AFS token response: %d", type);
808: }
809: }
810:
811: #endif /* AFS */
812:
813: /*
814: * Tries to authenticate with any string-based challenge/response system.
815: * Note that the client code is not tied to s/key or TIS.
816: */
1.35 itojun 817: static int
1.32 markus 818: try_challenge_response_authentication(void)
1.1 markus 819: {
820: int type, i;
821: int payload_len;
1.13 markus 822: u_int clen;
1.12 markus 823: char prompt[1024];
1.1 markus 824: char *challenge, *response;
1.40 markus 825:
826: debug("Doing challenge response authentication.");
827:
1.12 markus 828: for (i = 0; i < options.number_of_password_prompts; i++) {
829: /* request a challenge */
830: packet_start(SSH_CMSG_AUTH_TIS);
831: packet_send();
832: packet_write_wait();
1.1 markus 833:
1.12 markus 834: type = packet_read(&payload_len);
835: if (type != SSH_SMSG_FAILURE &&
836: type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
837: packet_disconnect("Protocol error: got %d in response "
1.20 markus 838: "to SSH_CMSG_AUTH_TIS", type);
1.12 markus 839: }
840: if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
1.20 markus 841: debug("No challenge.");
1.12 markus 842: return 0;
843: }
844: challenge = packet_get_string(&clen);
845: packet_integrity_check(payload_len, (4 + clen), type);
1.16 markus 846: snprintf(prompt, sizeof prompt, "%s%s", challenge,
1.42 deraadt 847: strchr(challenge, '\n') ? "" : "\nResponse: ");
1.12 markus 848: xfree(challenge);
1.1 markus 849: if (i != 0)
850: error("Permission denied, please try again.");
1.12 markus 851: if (options.cipher == SSH_CIPHER_NONE)
852: log("WARNING: Encryption is disabled! "
853: "Reponse will be transmitted in clear text.");
854: response = read_passphrase(prompt, 0);
855: if (strcmp(response, "") == 0) {
856: xfree(response);
857: break;
858: }
1.1 markus 859: packet_start(SSH_CMSG_AUTH_TIS_RESPONSE);
1.27 markus 860: ssh_put_password(response);
1.1 markus 861: memset(response, 0, strlen(response));
862: xfree(response);
863: packet_send();
864: packet_write_wait();
865: type = packet_read(&payload_len);
866: if (type == SSH_SMSG_SUCCESS)
867: return 1;
868: if (type != SSH_SMSG_FAILURE)
869: packet_disconnect("Protocol error: got %d in response "
1.20 markus 870: "to SSH_CMSG_AUTH_TIS_RESPONSE", type);
1.1 markus 871: }
872: /* failure */
873: return 0;
874: }
875:
876: /*
877: * Tries to authenticate with plain passwd authentication.
878: */
1.35 itojun 879: static int
1.1 markus 880: try_password_authentication(char *prompt)
881: {
882: int type, i, payload_len;
883: char *password;
884:
885: debug("Doing password authentication.");
886: if (options.cipher == SSH_CIPHER_NONE)
887: log("WARNING: Encryption is disabled! Password will be transmitted in clear text.");
888: for (i = 0; i < options.number_of_password_prompts; i++) {
889: if (i != 0)
890: error("Permission denied, please try again.");
891: password = read_passphrase(prompt, 0);
892: packet_start(SSH_CMSG_AUTH_PASSWORD);
1.27 markus 893: ssh_put_password(password);
1.1 markus 894: memset(password, 0, strlen(password));
895: xfree(password);
896: packet_send();
897: packet_write_wait();
898:
899: type = packet_read(&payload_len);
900: if (type == SSH_SMSG_SUCCESS)
901: return 1;
902: if (type != SSH_SMSG_FAILURE)
903: packet_disconnect("Protocol error: got %d in response to passwd auth", type);
904: }
905: /* failure */
906: return 0;
907: }
908:
909: /*
910: * SSH1 key exchange
911: */
912: void
913: ssh_kex(char *host, struct sockaddr *hostaddr)
914: {
915: int i;
916: BIGNUM *key;
1.43 ! markus 917: Key *host_key, *server_key;
1.1 markus 918: int bits, rbits;
919: int ssh_cipher_default = SSH_CIPHER_3DES;
1.13 markus 920: u_char session_key[SSH_SESSION_KEY_LENGTH];
921: u_char cookie[8];
922: u_int supported_ciphers;
923: u_int server_flags, client_flags;
1.1 markus 924: int payload_len, clen, sum_len = 0;
925: u_int32_t rand = 0;
926:
927: debug("Waiting for server public key.");
928:
929: /* Wait for a public key packet from the server. */
930: packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY);
931:
932: /* Get cookie from the packet. */
933: for (i = 0; i < 8; i++)
934: cookie[i] = packet_get_char();
935:
936: /* Get the public key. */
1.43 ! markus 937: server_key = key_new(KEY_RSA1);
! 938: bits = packet_get_int();
! 939: packet_get_bignum(server_key->rsa->e, &clen);
1.1 markus 940: sum_len += clen;
1.43 ! markus 941: packet_get_bignum(server_key->rsa->n, &clen);
1.1 markus 942: sum_len += clen;
943:
1.43 ! markus 944: rbits = BN_num_bits(server_key->rsa->n);
1.1 markus 945: if (bits != rbits) {
946: log("Warning: Server lies about size of server public key: "
947: "actual size is %d bits vs. announced %d.", rbits, bits);
948: log("Warning: This may be due to an old implementation of ssh.");
949: }
950: /* Get the host key. */
1.43 ! markus 951: host_key = key_new(KEY_RSA1);
! 952: bits = packet_get_int();
! 953: packet_get_bignum(host_key->rsa->e, &clen);
1.1 markus 954: sum_len += clen;
1.43 ! markus 955: packet_get_bignum(host_key->rsa->n, &clen);
1.1 markus 956: sum_len += clen;
957:
1.43 ! markus 958: rbits = BN_num_bits(host_key->rsa->n);
1.1 markus 959: if (bits != rbits) {
960: log("Warning: Server lies about size of server host key: "
961: "actual size is %d bits vs. announced %d.", rbits, bits);
962: log("Warning: This may be due to an old implementation of ssh.");
963: }
964:
965: /* Get protocol flags. */
966: server_flags = packet_get_int();
967: packet_set_protocol_flags(server_flags);
968:
969: supported_ciphers = packet_get_int();
970: supported_authentications = packet_get_int();
971:
972: debug("Received server public key (%d bits) and host key (%d bits).",
1.43 ! markus 973: BN_num_bits(server_key->rsa->n), BN_num_bits(host_key->rsa->n));
1.1 markus 974:
975: packet_integrity_check(payload_len,
1.42 deraadt 976: 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4,
977: SSH_SMSG_PUBLIC_KEY);
1.43 ! markus 978: if (verify_host_key(host, hostaddr, host_key) == -1)
1.41 markus 979: fatal("Host key verification failed.");
1.1 markus 980:
981: client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN;
982:
1.43 ! markus 983: compute_session_id(session_id, cookie, host_key->rsa->n, server_key->rsa->n);
1.1 markus 984:
985: /* Generate a session key. */
986: arc4random_stir();
987:
988: /*
989: * Generate an encryption key for the session. The key is a 256 bit
990: * random number, interpreted as a 32-byte key, with the least
991: * significant 8 bits being the first byte of the key.
992: */
993: for (i = 0; i < 32; i++) {
994: if (i % 4 == 0)
995: rand = arc4random();
996: session_key[i] = rand & 0xff;
997: rand >>= 8;
998: }
999:
1000: /*
1001: * According to the protocol spec, the first byte of the session key
1002: * is the highest byte of the integer. The session key is xored with
1003: * the first 16 bytes of the session id.
1004: */
1.43 ! markus 1005: if ((key = BN_new()) == NULL)
! 1006: fatal("respond_to_rsa_challenge: BN_new failed");
1.1 markus 1007: BN_set_word(key, 0);
1008: for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
1009: BN_lshift(key, key, 8);
1010: if (i < 16)
1011: BN_add_word(key, session_key[i] ^ session_id[i]);
1012: else
1013: BN_add_word(key, session_key[i]);
1014: }
1015:
1016: /*
1017: * Encrypt the integer using the public key and host key of the
1018: * server (key with smaller modulus first).
1019: */
1.43 ! markus 1020: if (BN_cmp(server_key->rsa->n, host_key->rsa->n) < 0) {
1.1 markus 1021: /* Public key has smaller modulus. */
1.43 ! markus 1022: if (BN_num_bits(host_key->rsa->n) <
! 1023: BN_num_bits(server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
! 1024: fatal("respond_to_rsa_challenge: host_key %d < server_key %d + "
1.42 deraadt 1025: "SSH_KEY_BITS_RESERVED %d",
1.43 ! markus 1026: BN_num_bits(host_key->rsa->n),
! 1027: BN_num_bits(server_key->rsa->n),
1.42 deraadt 1028: SSH_KEY_BITS_RESERVED);
1.1 markus 1029: }
1.43 ! markus 1030: rsa_public_encrypt(key, key, server_key->rsa);
! 1031: rsa_public_encrypt(key, key, host_key->rsa);
1.1 markus 1032: } else {
1033: /* Host key has smaller modulus (or they are equal). */
1.43 ! markus 1034: if (BN_num_bits(server_key->rsa->n) <
! 1035: BN_num_bits(host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
! 1036: fatal("respond_to_rsa_challenge: server_key %d < host_key %d + "
1.42 deraadt 1037: "SSH_KEY_BITS_RESERVED %d",
1.43 ! markus 1038: BN_num_bits(server_key->rsa->n),
! 1039: BN_num_bits(host_key->rsa->n),
1.42 deraadt 1040: SSH_KEY_BITS_RESERVED);
1.1 markus 1041: }
1.43 ! markus 1042: rsa_public_encrypt(key, key, host_key->rsa);
! 1043: rsa_public_encrypt(key, key, server_key->rsa);
1.1 markus 1044: }
1045:
1046: /* Destroy the public keys since we no longer need them. */
1.43 ! markus 1047: key_free(server_key);
! 1048: key_free(host_key);
1.1 markus 1049:
1.11 markus 1050: if (options.cipher == SSH_CIPHER_NOT_SET) {
1051: if (cipher_mask_ssh1(1) & supported_ciphers & (1 << ssh_cipher_default))
1052: options.cipher = ssh_cipher_default;
1053: } else if (options.cipher == SSH_CIPHER_ILLEGAL ||
1.10 markus 1054: !(cipher_mask_ssh1(1) & (1 << options.cipher))) {
1.3 markus 1055: log("No valid SSH1 cipher, using %.100s instead.",
1.7 markus 1056: cipher_name(ssh_cipher_default));
1057: options.cipher = ssh_cipher_default;
1.1 markus 1058: }
1059: /* Check that the selected cipher is supported. */
1060: if (!(supported_ciphers & (1 << options.cipher)))
1061: fatal("Selected cipher type %.100s not supported by server.",
1.42 deraadt 1062: cipher_name(options.cipher));
1.1 markus 1063:
1064: debug("Encryption type: %.100s", cipher_name(options.cipher));
1065:
1066: /* Send the encrypted session key to the server. */
1067: packet_start(SSH_CMSG_SESSION_KEY);
1068: packet_put_char(options.cipher);
1069:
1070: /* Send the cookie back to the server. */
1071: for (i = 0; i < 8; i++)
1072: packet_put_char(cookie[i]);
1073:
1074: /* Send and destroy the encrypted encryption key integer. */
1075: packet_put_bignum(key);
1076: BN_clear_free(key);
1077:
1078: /* Send protocol flags. */
1079: packet_put_int(client_flags);
1080:
1081: /* Send the packet now. */
1082: packet_send();
1083: packet_write_wait();
1084:
1085: debug("Sent encrypted session key.");
1086:
1087: /* Set the encryption key. */
1088: packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher);
1089:
1090: /* We will no longer need the session key here. Destroy any extra copies. */
1091: memset(session_key, 0, sizeof(session_key));
1092:
1093: /*
1094: * Expect a success message from the server. Note that this message
1095: * will be received in encrypted form.
1096: */
1097: packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);
1098:
1099: debug("Received encrypted confirmation.");
1100: }
1101:
1102: /*
1103: * Authenticate user
1104: */
1105: void
1.30 markus 1106: ssh_userauth1(const char *local_user, const char *server_user, char *host,
1107: Key **keys, int nkeys)
1.1 markus 1108: {
1.37 dugsong 1109: #ifdef KRB5
1110: krb5_context context = NULL;
1111: krb5_auth_context auth_context = NULL;
1112: #endif
1.1 markus 1113: int i, type;
1114: int payload_len;
1.42 deraadt 1115:
1.1 markus 1116: if (supported_authentications == 0)
1.30 markus 1117: fatal("ssh_userauth1: server supports no auth methods");
1.1 markus 1118:
1119: /* Send the name of the user to log in as on the server. */
1120: packet_start(SSH_CMSG_USER);
1.33 markus 1121: packet_put_cstring(server_user);
1.1 markus 1122: packet_send();
1123: packet_write_wait();
1124:
1125: /*
1126: * The server should respond with success if no authentication is
1127: * needed (the user has no password). Otherwise the server responds
1128: * with failure.
1129: */
1130: type = packet_read(&payload_len);
1131:
1132: /* check whether the connection was accepted without authentication. */
1133: if (type == SSH_SMSG_SUCCESS)
1.37 dugsong 1134: goto success;
1.1 markus 1135: if (type != SSH_SMSG_FAILURE)
1.37 dugsong 1136: packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", type);
1.42 deraadt 1137:
1.37 dugsong 1138: #ifdef KRB5
1139: if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) &&
1.42 deraadt 1140: options.kerberos_authentication) {
1.37 dugsong 1141: debug("Trying Kerberos v5 authentication.");
1.42 deraadt 1142:
1.37 dugsong 1143: if (try_krb5_authentication(&context, &auth_context)) {
1144: type = packet_read(&payload_len);
1145: if (type == SSH_SMSG_SUCCESS)
1146: goto success;
1147: if (type != SSH_SMSG_FAILURE)
1148: packet_disconnect("Protocol error: got %d in response to Kerberos v5 auth", type);
1149: }
1.1 markus 1150: }
1.37 dugsong 1151: #endif /* KRB5 */
1.42 deraadt 1152:
1.1 markus 1153: #ifdef KRB4
1154: if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) &&
1155: options.kerberos_authentication) {
1.37 dugsong 1156: debug("Trying Kerberos v4 authentication.");
1.42 deraadt 1157:
1.37 dugsong 1158: if (try_krb4_authentication()) {
1.1 markus 1159: type = packet_read(&payload_len);
1160: if (type == SSH_SMSG_SUCCESS)
1.37 dugsong 1161: goto success;
1.1 markus 1162: if (type != SSH_SMSG_FAILURE)
1.37 dugsong 1163: packet_disconnect("Protocol error: got %d in response to Kerberos v4 auth", type);
1.1 markus 1164: }
1165: }
1166: #endif /* KRB4 */
1.42 deraadt 1167:
1.1 markus 1168: /*
1169: * Use rhosts authentication if running in privileged socket and we
1170: * do not wish to remain anonymous.
1171: */
1172: if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) &&
1173: options.rhosts_authentication) {
1174: debug("Trying rhosts authentication.");
1175: packet_start(SSH_CMSG_AUTH_RHOSTS);
1.33 markus 1176: packet_put_cstring(local_user);
1.1 markus 1177: packet_send();
1178: packet_write_wait();
1179:
1180: /* The server should respond with success or failure. */
1181: type = packet_read(&payload_len);
1182: if (type == SSH_SMSG_SUCCESS)
1.37 dugsong 1183: goto success;
1.1 markus 1184: if (type != SSH_SMSG_FAILURE)
1185: packet_disconnect("Protocol error: got %d in response to rhosts auth",
1186: type);
1187: }
1188: /*
1189: * Try .rhosts or /etc/hosts.equiv authentication with RSA host
1190: * authentication.
1191: */
1192: if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) &&
1.30 markus 1193: options.rhosts_rsa_authentication) {
1194: for (i = 0; i < nkeys; i++) {
1.31 markus 1195: if (keys[i] != NULL && keys[i]->type == KEY_RSA1 &&
1.30 markus 1196: try_rhosts_rsa_authentication(local_user, keys[i]))
1.37 dugsong 1197: goto success;
1.30 markus 1198: }
1.1 markus 1199: }
1200: /* Try RSA authentication if the server supports it. */
1201: if ((supported_authentications & (1 << SSH_AUTH_RSA)) &&
1202: options.rsa_authentication) {
1203: /*
1204: * Try RSA authentication using the authentication agent. The
1205: * agent is tried first because no passphrase is needed for
1206: * it, whereas identity files may require passphrases.
1207: */
1208: if (try_agent_authentication())
1.37 dugsong 1209: goto success;
1.1 markus 1210:
1211: /* Try RSA authentication for each identity. */
1212: for (i = 0; i < options.num_identity_files; i++)
1.28 markus 1213: if (options.identity_keys[i] != NULL &&
1214: options.identity_keys[i]->type == KEY_RSA1 &&
1.38 markus 1215: try_rsa_authentication(i))
1.37 dugsong 1216: goto success;
1.1 markus 1217: }
1.20 markus 1218: /* Try challenge response authentication if the server supports it. */
1.1 markus 1219: if ((supported_authentications & (1 << SSH_AUTH_TIS)) &&
1.32 markus 1220: options.challenge_response_authentication && !options.batch_mode) {
1221: if (try_challenge_response_authentication())
1.37 dugsong 1222: goto success;
1.1 markus 1223: }
1224: /* Try password authentication if the server supports it. */
1225: if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) &&
1226: options.password_authentication && !options.batch_mode) {
1227: char prompt[80];
1228:
1.23 itojun 1229: snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1.1 markus 1230: server_user, host);
1231: if (try_password_authentication(prompt))
1.37 dugsong 1232: goto success;
1.1 markus 1233: }
1234: /* All authentication methods have failed. Exit with an error message. */
1235: fatal("Permission denied.");
1236: /* NOTREACHED */
1.37 dugsong 1237:
1238: success:
1239: #ifdef KRB5
1240: /* Try Kerberos v5 TGT passing. */
1241: if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&
1242: options.kerberos_tgt_passing && context && auth_context) {
1243: if (options.cipher == SSH_CIPHER_NONE)
1244: log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");
1245: send_krb5_tgt(context, auth_context);
1246: }
1247: if (auth_context)
1248: krb5_auth_con_free(context, auth_context);
1249: if (context)
1250: krb5_free_context(context);
1251: #endif
1.42 deraadt 1252:
1.37 dugsong 1253: #ifdef AFS
1254: /* Try Kerberos v4 TGT passing if the server supports it. */
1255: if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&
1256: options.kerberos_tgt_passing) {
1257: if (options.cipher == SSH_CIPHER_NONE)
1258: log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");
1259: send_krb4_tgt();
1260: }
1261: /* Try AFS token passing if the server supports it. */
1262: if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) &&
1263: options.afs_token_passing && k_hasafs()) {
1264: if (options.cipher == SSH_CIPHER_NONE)
1265: log("WARNING: Encryption is disabled! Token will be transmitted in the clear!");
1266: send_afs_tokens();
1267: }
1268: #endif /* AFS */
1.39 stevesk 1269:
1270: return; /* need statement after label */
1.1 markus 1271: }
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