Annotation of src/usr.bin/ssh/sshconnect2.c, Revision 1.68
1.1 markus 1: /*
2: * Copyright (c) 2000 Markus Friedl. All rights reserved.
3: *
4: * Redistribution and use in source and binary forms, with or without
5: * modification, are permitted provided that the following conditions
6: * are met:
7: * 1. Redistributions of source code must retain the above copyright
8: * notice, this list of conditions and the following disclaimer.
9: * 2. Redistributions in binary form must reproduce the above copyright
10: * notice, this list of conditions and the following disclaimer in the
11: * documentation and/or other materials provided with the distribution.
12: *
13: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23: */
24:
25: #include "includes.h"
1.68 ! markus 26: RCSID("$OpenBSD: sshconnect2.c,v 1.67 2001/04/05 10:42:56 markus Exp $");
1.1 markus 27:
28: #include <openssl/bn.h>
29: #include <openssl/md5.h>
30: #include <openssl/dh.h>
31: #include <openssl/hmac.h>
32:
33: #include "ssh.h"
1.37 markus 34: #include "ssh2.h"
1.1 markus 35: #include "xmalloc.h"
36: #include "rsa.h"
37: #include "buffer.h"
38: #include "packet.h"
39: #include "uidswap.h"
40: #include "compat.h"
41: #include "bufaux.h"
1.37 markus 42: #include "cipher.h"
1.1 markus 43: #include "kex.h"
44: #include "myproposal.h"
45: #include "key.h"
46: #include "sshconnect.h"
47: #include "authfile.h"
1.23 markus 48: #include "cli.h"
1.57 provos 49: #include "dh.h"
1.17 markus 50: #include "authfd.h"
1.37 markus 51: #include "log.h"
52: #include "readconf.h"
53: #include "readpass.h"
1.53 markus 54: #include "match.h"
1.61 markus 55: #include "dispatch.h"
1.68 ! markus 56: #include "canohost.h"
1.22 provos 57:
1.1 markus 58: /* import */
59: extern char *client_version_string;
60: extern char *server_version_string;
61: extern Options options;
62:
63: /*
64: * SSH2 key exchange
65: */
66:
1.32 markus 67: u_char *session_id2 = NULL;
1.1 markus 68: int session_id2_len = 0;
69:
1.61 markus 70: char *xxx_host;
71: struct sockaddr *xxx_hostaddr;
72:
1.63 markus 73: Kex *xxx_kex = NULL;
74:
1.61 markus 75: int
76: check_host_key_callback(Key *hostkey)
77: {
78: check_host_key(xxx_host, xxx_hostaddr, hostkey,
79: options.user_hostfile2, options.system_hostfile2);
80: return 0;
81: }
82:
1.1 markus 83: void
1.22 provos 84: ssh_kex2(char *host, struct sockaddr *hostaddr)
85: {
86: Kex *kex;
1.61 markus 87:
88: xxx_host = host;
89: xxx_hostaddr = hostaddr;
1.22 provos 90:
1.29 markus 91: if (options.ciphers == (char *)-1) {
92: log("No valid ciphers for protocol version 2 given, using defaults.");
93: options.ciphers = NULL;
1.24 markus 94: }
1.22 provos 95: if (options.ciphers != NULL) {
96: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
97: myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
98: }
1.60 stevesk 99: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
100: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
101: myproposal[PROPOSAL_ENC_ALGS_STOC] =
102: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1.22 provos 103: if (options.compression) {
1.47 markus 104: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.22 provos 105: myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
106: } else {
1.47 markus 107: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.22 provos 108: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1.47 markus 109: }
110: if (options.macs != NULL) {
111: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
112: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1.22 provos 113: }
114:
1.65 markus 115: /* start key exchange */
1.64 markus 116: kex = kex_setup(myproposal);
1.61 markus 117: kex->client_version_string=client_version_string;
118: kex->server_version_string=server_version_string;
119: kex->check_host_key=&check_host_key_callback;
1.63 markus 120:
121: xxx_kex = kex;
1.22 provos 122:
1.66 markus 123: dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1.62 markus 124:
125: session_id2 = kex->session_id;
126: session_id2_len = kex->session_id_len;
1.22 provos 127:
128: #ifdef DEBUG_KEXDH
129: /* send 1st encrypted/maced/compressed message */
130: packet_start(SSH2_MSG_IGNORE);
131: packet_put_cstring("markus");
132: packet_send();
133: packet_write_wait();
134: #endif
1.61 markus 135: debug("done: ssh_kex2.");
1.1 markus 136: }
1.11 markus 137:
1.1 markus 138: /*
139: * Authenticate user
140: */
1.20 markus 141:
142: typedef struct Authctxt Authctxt;
143: typedef struct Authmethod Authmethod;
144:
145: typedef int sign_cb_fn(
146: Authctxt *authctxt, Key *key,
1.32 markus 147: u_char **sigp, int *lenp, u_char *data, int datalen);
1.20 markus 148:
149: struct Authctxt {
150: const char *server_user;
1.68 ! markus 151: const char *local_user;
1.20 markus 152: const char *host;
153: const char *service;
1.23 markus 154: Authmethod *method;
1.20 markus 155: int success;
1.51 markus 156: char *authlist;
1.68 ! markus 157: /* pubkey */
1.51 markus 158: Key *last_key;
159: sign_cb_fn *last_key_sign;
160: int last_key_hint;
1.68 ! markus 161: AuthenticationConnection *agent;
! 162: /* hostbased */
! 163: Key **keys;
! 164: int nkeys;
1.20 markus 165: };
166: struct Authmethod {
167: char *name; /* string to compare against server's list */
168: int (*userauth)(Authctxt *authctxt);
169: int *enabled; /* flag in option struct that enables method */
170: int *batch_flag; /* flag in option struct that disables method */
171: };
172:
173: void input_userauth_success(int type, int plen, void *ctxt);
174: void input_userauth_failure(int type, int plen, void *ctxt);
1.35 markus 175: void input_userauth_banner(int type, int plen, void *ctxt);
1.20 markus 176: void input_userauth_error(int type, int plen, void *ctxt);
1.23 markus 177: void input_userauth_info_req(int type, int plen, void *ctxt);
1.51 markus 178: void input_userauth_pk_ok(int type, int plen, void *ctxt);
1.23 markus 179:
180: int userauth_none(Authctxt *authctxt);
1.20 markus 181: int userauth_pubkey(Authctxt *authctxt);
182: int userauth_passwd(Authctxt *authctxt);
1.23 markus 183: int userauth_kbdint(Authctxt *authctxt);
1.68 ! markus 184: int userauth_hostbased(Authctxt *authctxt);
1.20 markus 185:
1.51 markus 186: void userauth(Authctxt *authctxt, char *authlist);
187:
188: int
189: sign_and_send_pubkey(Authctxt *authctxt, Key *k,
190: sign_cb_fn *sign_callback);
191: void clear_auth_state(Authctxt *authctxt);
192:
1.23 markus 193: Authmethod *authmethod_get(char *authlist);
194: Authmethod *authmethod_lookup(const char *name);
1.53 markus 195: char *authmethods_get(void);
1.20 markus 196:
197: Authmethod authmethods[] = {
198: {"publickey",
199: userauth_pubkey,
1.28 markus 200: &options.pubkey_authentication,
1.20 markus 201: NULL},
202: {"password",
203: userauth_passwd,
204: &options.password_authentication,
205: &options.batch_mode},
1.23 markus 206: {"keyboard-interactive",
207: userauth_kbdint,
208: &options.kbd_interactive_authentication,
209: &options.batch_mode},
1.68 ! markus 210: {"hostbased",
! 211: userauth_hostbased,
! 212: &options.hostbased_authentication,
! 213: NULL},
1.23 markus 214: {"none",
215: userauth_none,
216: NULL,
217: NULL},
1.20 markus 218: {NULL, NULL, NULL, NULL}
219: };
220:
221: void
1.68 ! markus 222: ssh_userauth2(const char *local_user, const char *server_user, char *host,
! 223: Key **keys, int nkeys)
1.20 markus 224: {
225: Authctxt authctxt;
226: int type;
227: int plen;
1.39 markus 228:
229: if (options.challenge_reponse_authentication)
230: options.kbd_interactive_authentication = 1;
1.20 markus 231:
232: debug("send SSH2_MSG_SERVICE_REQUEST");
233: packet_start(SSH2_MSG_SERVICE_REQUEST);
234: packet_put_cstring("ssh-userauth");
235: packet_send();
236: packet_write_wait();
237: type = packet_read(&plen);
238: if (type != SSH2_MSG_SERVICE_ACCEPT) {
239: fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
240: }
241: if (packet_remaining() > 0) {
242: char *reply = packet_get_string(&plen);
243: debug("service_accept: %s", reply);
244: xfree(reply);
245: } else {
246: debug("buggy server: service_accept w/o service");
247: }
248: packet_done();
249: debug("got SSH2_MSG_SERVICE_ACCEPT");
250:
1.53 markus 251: if (options.preferred_authentications == NULL)
252: options.preferred_authentications = authmethods_get();
253:
1.20 markus 254: /* setup authentication context */
255: authctxt.agent = ssh_get_authentication_connection();
256: authctxt.server_user = server_user;
1.68 ! markus 257: authctxt.local_user = local_user;
1.20 markus 258: authctxt.host = host;
259: authctxt.service = "ssh-connection"; /* service name */
260: authctxt.success = 0;
1.23 markus 261: authctxt.method = authmethod_lookup("none");
1.51 markus 262: authctxt.authlist = NULL;
1.68 ! markus 263: authctxt.keys = keys;
! 264: authctxt.nkeys = nkeys;
1.23 markus 265: if (authctxt.method == NULL)
266: fatal("ssh_userauth2: internal error: cannot send userauth none request");
1.20 markus 267:
268: /* initial userauth request */
1.23 markus 269: userauth_none(&authctxt);
1.20 markus 270:
1.65 markus 271: dispatch_init(&input_userauth_error);
1.20 markus 272: dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
273: dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
1.35 markus 274: dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
1.20 markus 275: dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
276:
277: if (authctxt.agent != NULL)
278: ssh_close_authentication_connection(authctxt.agent);
279:
1.34 markus 280: debug("ssh-userauth2 successful: method %s", authctxt.method->name);
1.20 markus 281: }
282: void
1.51 markus 283: userauth(Authctxt *authctxt, char *authlist)
284: {
285: if (authlist == NULL) {
286: authlist = authctxt->authlist;
287: } else {
288: if (authctxt->authlist)
289: xfree(authctxt->authlist);
290: authctxt->authlist = authlist;
291: }
292: for (;;) {
293: Authmethod *method = authmethod_get(authlist);
294: if (method == NULL)
295: fatal("Permission denied (%s).", authlist);
296: authctxt->method = method;
297: if (method->userauth(authctxt) != 0) {
298: debug2("we sent a %s packet, wait for reply", method->name);
299: break;
300: } else {
301: debug2("we did not send a packet, disable method");
302: method->enabled = NULL;
303: }
304: }
305: }
306: void
1.20 markus 307: input_userauth_error(int type, int plen, void *ctxt)
308: {
1.35 markus 309: fatal("input_userauth_error: bad message during authentication: "
310: "type %d", type);
311: }
312: void
313: input_userauth_banner(int type, int plen, void *ctxt)
314: {
315: char *msg, *lang;
316: debug3("input_userauth_banner");
317: msg = packet_get_string(NULL);
318: lang = packet_get_string(NULL);
319: fprintf(stderr, "%s", msg);
320: xfree(msg);
321: xfree(lang);
1.20 markus 322: }
323: void
324: input_userauth_success(int type, int plen, void *ctxt)
325: {
326: Authctxt *authctxt = ctxt;
327: if (authctxt == NULL)
328: fatal("input_userauth_success: no authentication context");
1.51 markus 329: if (authctxt->authlist)
330: xfree(authctxt->authlist);
331: clear_auth_state(authctxt);
1.20 markus 332: authctxt->success = 1; /* break out */
333: }
334: void
335: input_userauth_failure(int type, int plen, void *ctxt)
336: {
337: Authctxt *authctxt = ctxt;
338: char *authlist = NULL;
339: int partial;
340:
341: if (authctxt == NULL)
342: fatal("input_userauth_failure: no authentication context");
343:
1.23 markus 344: authlist = packet_get_string(NULL);
1.20 markus 345: partial = packet_get_char();
346: packet_done();
347:
348: if (partial != 0)
1.45 markus 349: log("Authenticated with partial success.");
1.20 markus 350: debug("authentications that can continue: %s", authlist);
351:
1.51 markus 352: clear_auth_state(authctxt);
353: userauth(authctxt, authlist);
354: }
355: void
356: input_userauth_pk_ok(int type, int plen, void *ctxt)
357: {
358: Authctxt *authctxt = ctxt;
359: Key *key = NULL;
360: Buffer b;
361: int alen, blen, pktype, sent = 0;
1.54 markus 362: char *pkalg, *pkblob, *fp;
1.51 markus 363:
364: if (authctxt == NULL)
365: fatal("input_userauth_pk_ok: no authentication context");
366: if (datafellows & SSH_BUG_PKOK) {
367: /* this is similar to SSH_BUG_PKAUTH */
368: debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
369: pkblob = packet_get_string(&blen);
370: buffer_init(&b);
371: buffer_append(&b, pkblob, blen);
372: pkalg = buffer_get_string(&b, &alen);
373: buffer_free(&b);
374: } else {
375: pkalg = packet_get_string(&alen);
376: pkblob = packet_get_string(&blen);
377: }
378: packet_done();
379:
380: debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
381: pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
382:
383: do {
384: if (authctxt->last_key == NULL ||
385: authctxt->last_key_sign == NULL) {
386: debug("no last key or no sign cb");
387: break;
388: }
389: if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
390: debug("unknown pkalg %s", pkalg);
391: break;
392: }
393: if ((key = key_from_blob(pkblob, blen)) == NULL) {
394: debug("no key from blob. pkalg %s", pkalg);
395: break;
396: }
1.54 markus 397: fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
398: debug2("input_userauth_pk_ok: fp %s", fp);
399: xfree(fp);
1.51 markus 400: if (!key_equal(key, authctxt->last_key)) {
401: debug("key != last_key");
1.20 markus 402: break;
403: }
1.51 markus 404: sent = sign_and_send_pubkey(authctxt, key,
405: authctxt->last_key_sign);
406: } while(0);
407:
408: if (key != NULL)
409: key_free(key);
410: xfree(pkalg);
411: xfree(pkblob);
412:
413: /* unregister */
414: clear_auth_state(authctxt);
415: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
416:
417: /* try another method if we did not send a packet*/
418: if (sent == 0)
419: userauth(authctxt, NULL);
420:
1.20 markus 421: }
422:
1.1 markus 423: int
1.23 markus 424: userauth_none(Authctxt *authctxt)
425: {
426: /* initial userauth request */
427: packet_start(SSH2_MSG_USERAUTH_REQUEST);
428: packet_put_cstring(authctxt->server_user);
429: packet_put_cstring(authctxt->service);
430: packet_put_cstring(authctxt->method->name);
431: packet_send();
432: return 1;
433: }
434:
435: int
1.20 markus 436: userauth_passwd(Authctxt *authctxt)
1.1 markus 437: {
1.6 markus 438: static int attempt = 0;
1.1 markus 439: char prompt[80];
440: char *password;
1.6 markus 441:
1.13 todd 442: if (attempt++ >= options.number_of_password_prompts)
1.6 markus 443: return 0;
1.13 todd 444:
445: if(attempt != 1)
446: error("Permission denied, please try again.");
1.1 markus 447:
1.43 itojun 448: snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1.20 markus 449: authctxt->server_user, authctxt->host);
1.1 markus 450: password = read_passphrase(prompt, 0);
451: packet_start(SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 452: packet_put_cstring(authctxt->server_user);
453: packet_put_cstring(authctxt->service);
1.23 markus 454: packet_put_cstring(authctxt->method->name);
1.1 markus 455: packet_put_char(0);
1.49 markus 456: packet_put_cstring(password);
1.1 markus 457: memset(password, 0, strlen(password));
458: xfree(password);
1.49 markus 459: packet_inject_ignore(64);
1.1 markus 460: packet_send();
461: return 1;
462: }
463:
1.51 markus 464: void
465: clear_auth_state(Authctxt *authctxt)
466: {
467: /* XXX clear authentication state */
468: if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
469: debug3("clear_auth_state: key_free %p", authctxt->last_key);
470: key_free(authctxt->last_key);
471: }
472: authctxt->last_key = NULL;
473: authctxt->last_key_hint = -2;
474: authctxt->last_key_sign = NULL;
475: }
476:
1.17 markus 477: int
1.20 markus 478: sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
1.1 markus 479: {
480: Buffer b;
1.32 markus 481: u_char *blob, *signature;
1.1 markus 482: int bloblen, slen;
1.14 markus 483: int skip = 0;
1.17 markus 484: int ret = -1;
1.23 markus 485: int have_sig = 1;
1.1 markus 486:
1.30 markus 487: debug3("sign_and_send_pubkey");
1.51 markus 488:
1.28 markus 489: if (key_to_blob(k, &blob, &bloblen) == 0) {
490: /* we cannot handle this key */
1.30 markus 491: debug3("sign_and_send_pubkey: cannot handle key");
1.28 markus 492: return 0;
493: }
1.1 markus 494: /* data to be signed */
495: buffer_init(&b);
1.26 markus 496: if (datafellows & SSH_OLD_SESSIONID) {
497: buffer_append(&b, session_id2, session_id2_len);
1.41 stevesk 498: skip = session_id2_len;
1.26 markus 499: } else {
1.14 markus 500: buffer_put_string(&b, session_id2, session_id2_len);
501: skip = buffer_len(&b);
502: }
1.1 markus 503: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 504: buffer_put_cstring(&b, authctxt->server_user);
1.10 markus 505: buffer_put_cstring(&b,
1.30 markus 506: datafellows & SSH_BUG_PKSERVICE ?
1.10 markus 507: "ssh-userauth" :
1.20 markus 508: authctxt->service);
1.30 markus 509: if (datafellows & SSH_BUG_PKAUTH) {
510: buffer_put_char(&b, have_sig);
511: } else {
512: buffer_put_cstring(&b, authctxt->method->name);
513: buffer_put_char(&b, have_sig);
1.41 stevesk 514: buffer_put_cstring(&b, key_ssh_name(k));
1.30 markus 515: }
1.1 markus 516: buffer_put_string(&b, blob, bloblen);
517:
518: /* generate signature */
1.51 markus 519: ret = (*sign_callback)(authctxt, k, &signature, &slen,
520: buffer_ptr(&b), buffer_len(&b));
1.17 markus 521: if (ret == -1) {
522: xfree(blob);
523: buffer_free(&b);
524: return 0;
525: }
1.28 markus 526: #ifdef DEBUG_PK
1.1 markus 527: buffer_dump(&b);
528: #endif
1.30 markus 529: if (datafellows & SSH_BUG_PKSERVICE) {
1.10 markus 530: buffer_clear(&b);
531: buffer_append(&b, session_id2, session_id2_len);
1.51 markus 532: skip = session_id2_len;
1.10 markus 533: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 534: buffer_put_cstring(&b, authctxt->server_user);
535: buffer_put_cstring(&b, authctxt->service);
1.23 markus 536: buffer_put_cstring(&b, authctxt->method->name);
537: buffer_put_char(&b, have_sig);
1.30 markus 538: if (!(datafellows & SSH_BUG_PKAUTH))
1.41 stevesk 539: buffer_put_cstring(&b, key_ssh_name(k));
1.10 markus 540: buffer_put_string(&b, blob, bloblen);
541: }
542: xfree(blob);
1.51 markus 543:
1.1 markus 544: /* append signature */
545: buffer_put_string(&b, signature, slen);
546: xfree(signature);
547:
548: /* skip session id and packet type */
1.14 markus 549: if (buffer_len(&b) < skip + 1)
1.20 markus 550: fatal("userauth_pubkey: internal error");
1.14 markus 551: buffer_consume(&b, skip + 1);
1.1 markus 552:
553: /* put remaining data from buffer into packet */
554: packet_start(SSH2_MSG_USERAUTH_REQUEST);
555: packet_put_raw(buffer_ptr(&b), buffer_len(&b));
556: buffer_free(&b);
557: packet_send();
1.17 markus 558:
559: return 1;
1.16 markus 560: }
561:
1.51 markus 562: int
563: send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
564: int hint)
1.20 markus 565: {
1.51 markus 566: u_char *blob;
567: int bloblen, have_sig = 0;
1.20 markus 568:
1.51 markus 569: debug3("send_pubkey_test");
1.16 markus 570:
1.51 markus 571: if (key_to_blob(k, &blob, &bloblen) == 0) {
572: /* we cannot handle this key */
573: debug3("send_pubkey_test: cannot handle key");
1.16 markus 574: return 0;
575: }
1.51 markus 576: /* register callback for USERAUTH_PK_OK message */
577: authctxt->last_key_sign = sign_callback;
578: authctxt->last_key_hint = hint;
579: authctxt->last_key = k;
580: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
581:
582: packet_start(SSH2_MSG_USERAUTH_REQUEST);
583: packet_put_cstring(authctxt->server_user);
584: packet_put_cstring(authctxt->service);
585: packet_put_cstring(authctxt->method->name);
586: packet_put_char(have_sig);
587: if (!(datafellows & SSH_BUG_PKAUTH))
588: packet_put_cstring(key_ssh_name(k));
589: packet_put_string(blob, bloblen);
590: xfree(blob);
591: packet_send();
592: return 1;
593: }
594:
595: Key *
596: load_identity_file(char *filename)
597: {
598: Key *private;
599: char prompt[300], *passphrase;
1.56 markus 600: int quit, i;
1.52 markus 601: struct stat st;
1.16 markus 602:
1.52 markus 603: if (stat(filename, &st) < 0) {
604: debug3("no such identity: %s", filename);
605: return NULL;
606: }
1.56 markus 607: private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
608: if (private == NULL) {
609: if (options.batch_mode)
1.51 markus 610: return NULL;
1.16 markus 611: snprintf(prompt, sizeof prompt,
1.28 markus 612: "Enter passphrase for key '%.100s': ", filename);
1.20 markus 613: for (i = 0; i < options.number_of_password_prompts; i++) {
614: passphrase = read_passphrase(prompt, 0);
615: if (strcmp(passphrase, "") != 0) {
1.56 markus 616: private = key_load_private_type(KEY_UNSPEC, filename,
617: passphrase, NULL);
1.51 markus 618: quit = 0;
1.20 markus 619: } else {
620: debug2("no passphrase given, try next key");
1.51 markus 621: quit = 1;
1.20 markus 622: }
623: memset(passphrase, 0, strlen(passphrase));
624: xfree(passphrase);
1.56 markus 625: if (private != NULL || quit)
1.20 markus 626: break;
627: debug2("bad passphrase given, try again...");
1.16 markus 628: }
629: }
1.51 markus 630: return private;
631: }
632:
633: int
634: identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
635: u_char *data, int datalen)
636: {
637: Key *private;
638: int idx, ret;
639:
640: idx = authctxt->last_key_hint;
641: if (idx < 0)
642: return -1;
643: private = load_identity_file(options.identity_files[idx]);
644: if (private == NULL)
645: return -1;
646: ret = key_sign(private, sigp, lenp, data, datalen);
647: key_free(private);
1.17 markus 648: return ret;
649: }
650:
1.32 markus 651: int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
652: u_char *data, int datalen)
1.17 markus 653: {
1.20 markus 654: return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
1.17 markus 655: }
656:
1.51 markus 657: int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
658: u_char *data, int datalen)
659: {
1.67 markus 660: return key_sign(key, sigp, lenp, data, datalen);
1.51 markus 661: }
662:
1.17 markus 663: int
1.20 markus 664: userauth_pubkey_agent(Authctxt *authctxt)
1.17 markus 665: {
666: static int called = 0;
1.28 markus 667: int ret = 0;
1.17 markus 668: char *comment;
669: Key *k;
670:
671: if (called == 0) {
1.28 markus 672: if (ssh_get_num_identities(authctxt->agent, 2) == 0)
673: debug2("userauth_pubkey_agent: no keys at all");
1.20 markus 674: called = 1;
1.17 markus 675: }
1.28 markus 676: k = ssh_get_next_identity(authctxt->agent, &comment, 2);
1.20 markus 677: if (k == NULL) {
1.28 markus 678: debug2("userauth_pubkey_agent: no more keys");
679: } else {
1.51 markus 680: debug("userauth_pubkey_agent: testing agent key %s", comment);
1.28 markus 681: xfree(comment);
1.51 markus 682: ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
683: if (ret == 0)
684: key_free(k);
1.20 markus 685: }
1.28 markus 686: if (ret == 0)
687: debug2("userauth_pubkey_agent: no message sent");
1.17 markus 688: return ret;
1.1 markus 689: }
690:
1.20 markus 691: int
692: userauth_pubkey(Authctxt *authctxt)
693: {
694: static int idx = 0;
695: int sent = 0;
1.51 markus 696: Key *key;
697: char *filename;
1.20 markus 698:
1.28 markus 699: if (authctxt->agent != NULL) {
700: do {
701: sent = userauth_pubkey_agent(authctxt);
702: } while(!sent && authctxt->agent->howmany > 0);
703: }
704: while (!sent && idx < options.num_identity_files) {
1.51 markus 705: key = options.identity_keys[idx];
706: filename = options.identity_files[idx];
707: if (key == NULL) {
708: debug("try privkey: %s", filename);
709: key = load_identity_file(filename);
710: if (key != NULL) {
711: sent = sign_and_send_pubkey(authctxt, key,
712: key_sign_cb);
713: key_free(key);
714: }
715: } else if (key->type != KEY_RSA1) {
716: debug("try pubkey: %s", filename);
717: sent = send_pubkey_test(authctxt, key,
718: identity_sign_cb, idx);
719: }
1.28 markus 720: idx++;
721: }
1.20 markus 722: return sent;
723: }
724:
1.23 markus 725: /*
726: * Send userauth request message specifying keyboard-interactive method.
727: */
728: int
729: userauth_kbdint(Authctxt *authctxt)
730: {
731: static int attempt = 0;
732:
733: if (attempt++ >= options.number_of_password_prompts)
734: return 0;
735:
736: debug2("userauth_kbdint");
737: packet_start(SSH2_MSG_USERAUTH_REQUEST);
738: packet_put_cstring(authctxt->server_user);
739: packet_put_cstring(authctxt->service);
740: packet_put_cstring(authctxt->method->name);
741: packet_put_cstring(""); /* lang */
742: packet_put_cstring(options.kbd_interactive_devices ?
743: options.kbd_interactive_devices : "");
744: packet_send();
745:
746: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
747: return 1;
748: }
749:
750: /*
1.46 markus 751: * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1.23 markus 752: */
753: void
754: input_userauth_info_req(int type, int plen, void *ctxt)
755: {
756: Authctxt *authctxt = ctxt;
1.46 markus 757: char *name, *inst, *lang, *prompt, *response;
1.32 markus 758: u_int num_prompts, i;
1.23 markus 759: int echo = 0;
760:
761: debug2("input_userauth_info_req");
762:
763: if (authctxt == NULL)
764: fatal("input_userauth_info_req: no authentication context");
765:
766: name = packet_get_string(NULL);
767: inst = packet_get_string(NULL);
768: lang = packet_get_string(NULL);
769: if (strlen(name) > 0)
770: cli_mesg(name);
771: if (strlen(inst) > 0)
772: cli_mesg(inst);
1.46 markus 773: xfree(name);
1.23 markus 774: xfree(inst);
1.46 markus 775: xfree(lang);
1.23 markus 776:
777: num_prompts = packet_get_int();
778: /*
779: * Begin to build info response packet based on prompts requested.
780: * We commit to providing the correct number of responses, so if
781: * further on we run into a problem that prevents this, we have to
782: * be sure and clean this up and send a correct error response.
783: */
784: packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
785: packet_put_int(num_prompts);
786:
787: for (i = 0; i < num_prompts; i++) {
788: prompt = packet_get_string(NULL);
789: echo = packet_get_char();
790:
791: response = cli_prompt(prompt, echo);
792:
1.49 markus 793: packet_put_cstring(response);
1.23 markus 794: memset(response, 0, strlen(response));
795: xfree(response);
796: xfree(prompt);
797: }
798: packet_done(); /* done with parsing incoming message. */
799:
1.49 markus 800: packet_inject_ignore(64);
1.23 markus 801: packet_send();
1.68 ! markus 802: }
! 803:
! 804: /*
! 805: * this will be move to an external program (ssh-keysign) ASAP. ssh-keysign
! 806: * will be setuid-root and the sbit can be removed from /usr/bin/ssh.
! 807: */
! 808: int
! 809: userauth_hostbased(Authctxt *authctxt)
! 810: {
! 811: Key *private = NULL;
! 812: Buffer b;
! 813: u_char *signature, *blob;
! 814: char *chost, *pkalg, *p;
! 815: u_int blen, slen;
! 816: int ok, i, found = 0;
! 817:
! 818: p = get_local_name(packet_get_connection_in());
! 819: if (p == NULL) {
! 820: error("userauth_hostbased: cannot get local ipaddr/name");
! 821: return 0;
! 822: }
! 823: chost = xstrdup(p);
! 824: debug2("userauth_hostbased: chost %s", chost);
! 825: /* check for a useful key */
! 826: for (i = 0; i < authctxt->nkeys; i++) {
! 827: private = authctxt->keys[i];
! 828: if (private && private->type != KEY_RSA1) {
! 829: found = 1;
! 830: /* we take and free the key */
! 831: authctxt->keys[i] = NULL;
! 832: break;
! 833: }
! 834: }
! 835: if (!found) {
! 836: xfree(chost);
! 837: return 0;
! 838: }
! 839: if (key_to_blob(private, &blob, &blen) == 0) {
! 840: key_free(private);
! 841: xfree(chost);
! 842: return 0;
! 843: }
! 844: pkalg = xstrdup(key_ssh_name(private));
! 845: buffer_init(&b);
! 846: if (datafellows & SSH_OLD_SESSIONID) {
! 847: buffer_append(&b, session_id2, session_id2_len);
! 848: } else {
! 849: buffer_put_string(&b, session_id2, session_id2_len);
! 850: }
! 851: /* construct data */
! 852: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
! 853: buffer_put_cstring(&b, authctxt->server_user);
! 854: buffer_put_cstring(&b,
! 855: datafellows & SSH_BUG_HBSERVICE ?
! 856: "ssh-userauth" :
! 857: authctxt->service);
! 858: buffer_put_cstring(&b, authctxt->method->name);
! 859: buffer_put_cstring(&b, pkalg);
! 860: buffer_put_string(&b, blob, blen);
! 861: buffer_put_cstring(&b, chost);
! 862: buffer_put_cstring(&b, authctxt->local_user);
! 863: #ifdef DEBUG_PK
! 864: buffer_dump(&b);
! 865: #endif
! 866: debug2("xxx: chost %s", chost);
! 867: ok = key_sign(private, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
! 868: key_free(private);
! 869: buffer_free(&b);
! 870: if (ok != 0) {
! 871: error("key_sign failed");
! 872: xfree(chost);
! 873: xfree(pkalg);
! 874: return 0;
! 875: }
! 876: packet_start(SSH2_MSG_USERAUTH_REQUEST);
! 877: packet_put_cstring(authctxt->server_user);
! 878: packet_put_cstring(authctxt->service);
! 879: packet_put_cstring(authctxt->method->name);
! 880: packet_put_cstring(pkalg);
! 881: packet_put_string(blob, blen);
! 882: packet_put_cstring(chost);
! 883: packet_put_cstring(authctxt->local_user);
! 884: packet_put_string(signature, slen);
! 885: memset(signature, 's', slen);
! 886: xfree(signature);
! 887: xfree(chost);
! 888: xfree(pkalg);
! 889:
! 890: packet_send();
! 891: return 1;
1.23 markus 892: }
1.20 markus 893:
894: /* find auth method */
895:
896: /*
897: * given auth method name, if configurable options permit this method fill
898: * in auth_ident field and return true, otherwise return false.
899: */
900: int
901: authmethod_is_enabled(Authmethod *method)
902: {
903: if (method == NULL)
904: return 0;
905: /* return false if options indicate this method is disabled */
906: if (method->enabled == NULL || *method->enabled == 0)
907: return 0;
908: /* return false if batch mode is enabled but method needs interactive mode */
909: if (method->batch_flag != NULL && *method->batch_flag != 0)
910: return 0;
911: return 1;
912: }
913:
914: Authmethod *
915: authmethod_lookup(const char *name)
1.1 markus 916: {
1.20 markus 917: Authmethod *method = NULL;
918: if (name != NULL)
919: for (method = authmethods; method->name != NULL; method++)
920: if (strcmp(name, method->name) == 0)
921: return method;
922: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
923: return NULL;
924: }
1.1 markus 925:
1.53 markus 926: /* XXX internal state */
927: static Authmethod *current = NULL;
928: static char *supported = NULL;
929: static char *preferred = NULL;
1.20 markus 930: /*
931: * Given the authentication method list sent by the server, return the
932: * next method we should try. If the server initially sends a nil list,
1.67 markus 933: * use a built-in default list.
1.41 stevesk 934: */
1.20 markus 935: Authmethod *
936: authmethod_get(char *authlist)
937: {
1.53 markus 938:
939: char *name = NULL;
940: int next;
1.41 stevesk 941:
1.20 markus 942: /* Use a suitable default if we're passed a nil list. */
943: if (authlist == NULL || strlen(authlist) == 0)
1.53 markus 944: authlist = options.preferred_authentications;
1.20 markus 945:
1.53 markus 946: if (supported == NULL || strcmp(authlist, supported) != 0) {
947: debug3("start over, passed a different list %s", authlist);
948: if (supported != NULL)
949: xfree(supported);
950: supported = xstrdup(authlist);
951: preferred = options.preferred_authentications;
952: debug3("preferred %s", preferred);
953: current = NULL;
954: } else if (current != NULL && authmethod_is_enabled(current))
955: return current;
1.20 markus 956:
1.53 markus 957: for (;;) {
958: if ((name = match_list(preferred, supported, &next)) == NULL) {
959: debug("no more auth methods to try");
960: current = NULL;
961: return NULL;
962: }
963: preferred += next;
1.23 markus 964: debug3("authmethod_lookup %s", name);
1.53 markus 965: debug3("remaining preferred: %s", preferred);
966: if ((current = authmethod_lookup(name)) != NULL &&
967: authmethod_is_enabled(current)) {
1.23 markus 968: debug3("authmethod_is_enabled %s", name);
1.53 markus 969: debug("next auth method to try is %s", name);
970: return current;
1.23 markus 971: }
1.1 markus 972: }
1.53 markus 973: }
1.1 markus 974:
1.27 provos 975:
1.53 markus 976: #define DELIM ","
977: char *
978: authmethods_get(void)
979: {
980: Authmethod *method = NULL;
981: char buf[1024];
1.27 provos 982:
1.53 markus 983: buf[0] = '\0';
984: for (method = authmethods; method->name != NULL; method++) {
985: if (authmethod_is_enabled(method)) {
986: if (buf[0] != '\0')
987: strlcat(buf, DELIM, sizeof buf);
988: strlcat(buf, method->name, sizeof buf);
989: }
990: }
991: return xstrdup(buf);
1.1 markus 992: }