Annotation of src/usr.bin/ssh/sshconnect2.c, Revision 1.95
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"
1.95 ! markus 26: RCSID("$OpenBSD: sshconnect2.c,v 1.94 2002/01/25 21:00:24 markus Exp $");
1.1 markus 27:
28: #include "ssh.h"
1.37 markus 29: #include "ssh2.h"
1.1 markus 30: #include "xmalloc.h"
31: #include "buffer.h"
32: #include "packet.h"
33: #include "compat.h"
34: #include "bufaux.h"
1.37 markus 35: #include "cipher.h"
1.1 markus 36: #include "kex.h"
37: #include "myproposal.h"
38: #include "sshconnect.h"
39: #include "authfile.h"
1.57 provos 40: #include "dh.h"
1.17 markus 41: #include "authfd.h"
1.37 markus 42: #include "log.h"
43: #include "readconf.h"
44: #include "readpass.h"
1.53 markus 45: #include "match.h"
1.61 markus 46: #include "dispatch.h"
1.68 markus 47: #include "canohost.h"
1.22 provos 48:
1.1 markus 49: /* import */
50: extern char *client_version_string;
51: extern char *server_version_string;
52: extern Options options;
53:
54: /*
55: * SSH2 key exchange
56: */
57:
1.32 markus 58: u_char *session_id2 = NULL;
1.1 markus 59: int session_id2_len = 0;
60:
1.61 markus 61: char *xxx_host;
62: struct sockaddr *xxx_hostaddr;
63:
1.63 markus 64: Kex *xxx_kex = NULL;
65:
1.76 itojun 66: static int
1.75 markus 67: verify_host_key_callback(Key *hostkey)
1.61 markus 68: {
1.75 markus 69: if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
1.83 markus 70: fatal("Host key verification failed.");
1.61 markus 71: return 0;
72: }
73:
1.1 markus 74: void
1.22 provos 75: ssh_kex2(char *host, struct sockaddr *hostaddr)
76: {
77: Kex *kex;
1.61 markus 78:
79: xxx_host = host;
80: xxx_hostaddr = hostaddr;
1.22 provos 81:
1.29 markus 82: if (options.ciphers == (char *)-1) {
83: log("No valid ciphers for protocol version 2 given, using defaults.");
84: options.ciphers = NULL;
1.24 markus 85: }
1.22 provos 86: if (options.ciphers != NULL) {
87: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
88: myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
89: }
1.60 stevesk 90: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
91: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
92: myproposal[PROPOSAL_ENC_ALGS_STOC] =
93: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1.22 provos 94: if (options.compression) {
1.47 markus 95: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.22 provos 96: myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
97: } else {
1.47 markus 98: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.22 provos 99: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1.47 markus 100: }
101: if (options.macs != NULL) {
102: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
103: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1.22 provos 104: }
1.70 markus 105: if (options.hostkeyalgorithms != NULL)
1.88 deraadt 106: myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
1.70 markus 107: options.hostkeyalgorithms;
1.22 provos 108:
1.65 markus 109: /* start key exchange */
1.64 markus 110: kex = kex_setup(myproposal);
1.61 markus 111: kex->client_version_string=client_version_string;
112: kex->server_version_string=server_version_string;
1.75 markus 113: kex->verify_host_key=&verify_host_key_callback;
1.63 markus 114:
115: xxx_kex = kex;
1.22 provos 116:
1.66 markus 117: dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1.62 markus 118:
119: session_id2 = kex->session_id;
120: session_id2_len = kex->session_id_len;
1.22 provos 121:
122: #ifdef DEBUG_KEXDH
123: /* send 1st encrypted/maced/compressed message */
124: packet_start(SSH2_MSG_IGNORE);
125: packet_put_cstring("markus");
126: packet_send();
127: packet_write_wait();
128: #endif
1.61 markus 129: debug("done: ssh_kex2.");
1.1 markus 130: }
1.11 markus 131:
1.1 markus 132: /*
133: * Authenticate user
134: */
1.20 markus 135:
136: typedef struct Authctxt Authctxt;
137: typedef struct Authmethod Authmethod;
138:
139: typedef int sign_cb_fn(
140: Authctxt *authctxt, Key *key,
1.32 markus 141: u_char **sigp, int *lenp, u_char *data, int datalen);
1.20 markus 142:
143: struct Authctxt {
144: const char *server_user;
1.68 markus 145: const char *local_user;
1.20 markus 146: const char *host;
147: const char *service;
1.23 markus 148: Authmethod *method;
1.20 markus 149: int success;
1.51 markus 150: char *authlist;
1.68 markus 151: /* pubkey */
1.51 markus 152: Key *last_key;
153: sign_cb_fn *last_key_sign;
154: int last_key_hint;
1.68 markus 155: AuthenticationConnection *agent;
156: /* hostbased */
157: Key **keys;
158: int nkeys;
1.82 markus 159: /* kbd-interactive */
160: int info_req_seen;
1.20 markus 161: };
162: struct Authmethod {
163: char *name; /* string to compare against server's list */
164: int (*userauth)(Authctxt *authctxt);
165: int *enabled; /* flag in option struct that enables method */
166: int *batch_flag; /* flag in option struct that disables method */
167: };
168:
1.92 markus 169: void input_userauth_success(int, u_int32_t, void *);
170: void input_userauth_failure(int, u_int32_t, void *);
171: void input_userauth_banner(int, u_int32_t, void *);
172: void input_userauth_error(int, u_int32_t, void *);
173: void input_userauth_info_req(int, u_int32_t, void *);
174: void input_userauth_pk_ok(int, u_int32_t, void *);
1.86 itojun 175:
176: int userauth_none(Authctxt *);
177: int userauth_pubkey(Authctxt *);
178: int userauth_passwd(Authctxt *);
179: int userauth_kbdint(Authctxt *);
180: int userauth_hostbased(Authctxt *);
1.20 markus 181:
1.86 itojun 182: void userauth(Authctxt *, char *);
1.51 markus 183:
1.76 itojun 184: static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *);
185: static void clear_auth_state(Authctxt *);
186:
187: static Authmethod *authmethod_get(char *authlist);
188: static Authmethod *authmethod_lookup(const char *name);
189: static char *authmethods_get(void);
1.20 markus 190:
191: Authmethod authmethods[] = {
1.81 markus 192: {"hostbased",
193: userauth_hostbased,
194: &options.hostbased_authentication,
195: NULL},
1.20 markus 196: {"publickey",
197: userauth_pubkey,
1.28 markus 198: &options.pubkey_authentication,
1.20 markus 199: NULL},
1.81 markus 200: {"keyboard-interactive",
201: userauth_kbdint,
202: &options.kbd_interactive_authentication,
203: &options.batch_mode},
1.20 markus 204: {"password",
205: userauth_passwd,
206: &options.password_authentication,
1.23 markus 207: &options.batch_mode},
208: {"none",
209: userauth_none,
210: NULL,
211: NULL},
1.20 markus 212: {NULL, NULL, NULL, NULL}
213: };
214:
215: void
1.68 markus 216: ssh_userauth2(const char *local_user, const char *server_user, char *host,
217: Key **keys, int nkeys)
1.20 markus 218: {
219: Authctxt authctxt;
220: int type;
1.39 markus 221:
1.73 markus 222: if (options.challenge_response_authentication)
1.39 markus 223: options.kbd_interactive_authentication = 1;
1.20 markus 224:
225: debug("send SSH2_MSG_SERVICE_REQUEST");
226: packet_start(SSH2_MSG_SERVICE_REQUEST);
227: packet_put_cstring("ssh-userauth");
228: packet_send();
229: packet_write_wait();
1.91 markus 230: type = packet_read();
1.20 markus 231: if (type != SSH2_MSG_SERVICE_ACCEPT) {
232: fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
233: }
234: if (packet_remaining() > 0) {
1.91 markus 235: char *reply = packet_get_string(NULL);
1.20 markus 236: debug("service_accept: %s", reply);
237: xfree(reply);
238: } else {
239: debug("buggy server: service_accept w/o service");
240: }
1.90 markus 241: packet_check_eom();
1.20 markus 242: debug("got SSH2_MSG_SERVICE_ACCEPT");
243:
1.53 markus 244: if (options.preferred_authentications == NULL)
245: options.preferred_authentications = authmethods_get();
246:
1.20 markus 247: /* setup authentication context */
1.82 markus 248: memset(&authctxt, 0, sizeof(authctxt));
1.20 markus 249: authctxt.agent = ssh_get_authentication_connection();
250: authctxt.server_user = server_user;
1.68 markus 251: authctxt.local_user = local_user;
1.20 markus 252: authctxt.host = host;
253: authctxt.service = "ssh-connection"; /* service name */
254: authctxt.success = 0;
1.23 markus 255: authctxt.method = authmethod_lookup("none");
1.51 markus 256: authctxt.authlist = NULL;
1.68 markus 257: authctxt.keys = keys;
258: authctxt.nkeys = nkeys;
1.82 markus 259: authctxt.info_req_seen = 0;
1.23 markus 260: if (authctxt.method == NULL)
261: fatal("ssh_userauth2: internal error: cannot send userauth none request");
1.20 markus 262:
263: /* initial userauth request */
1.23 markus 264: userauth_none(&authctxt);
1.20 markus 265:
1.65 markus 266: dispatch_init(&input_userauth_error);
1.20 markus 267: dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
268: dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
1.35 markus 269: dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
1.20 markus 270: dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
271:
272: if (authctxt.agent != NULL)
273: ssh_close_authentication_connection(authctxt.agent);
274:
1.34 markus 275: debug("ssh-userauth2 successful: method %s", authctxt.method->name);
1.20 markus 276: }
277: void
1.51 markus 278: userauth(Authctxt *authctxt, char *authlist)
279: {
280: if (authlist == NULL) {
281: authlist = authctxt->authlist;
282: } else {
283: if (authctxt->authlist)
284: xfree(authctxt->authlist);
285: authctxt->authlist = authlist;
286: }
287: for (;;) {
288: Authmethod *method = authmethod_get(authlist);
289: if (method == NULL)
290: fatal("Permission denied (%s).", authlist);
291: authctxt->method = method;
292: if (method->userauth(authctxt) != 0) {
293: debug2("we sent a %s packet, wait for reply", method->name);
294: break;
295: } else {
296: debug2("we did not send a packet, disable method");
297: method->enabled = NULL;
298: }
299: }
300: }
301: void
1.92 markus 302: input_userauth_error(int type, u_int32_t seq, void *ctxt)
1.20 markus 303: {
1.35 markus 304: fatal("input_userauth_error: bad message during authentication: "
305: "type %d", type);
306: }
307: void
1.92 markus 308: input_userauth_banner(int type, u_int32_t seq, void *ctxt)
1.35 markus 309: {
310: char *msg, *lang;
311: debug3("input_userauth_banner");
312: msg = packet_get_string(NULL);
313: lang = packet_get_string(NULL);
314: fprintf(stderr, "%s", msg);
315: xfree(msg);
316: xfree(lang);
1.20 markus 317: }
318: void
1.92 markus 319: input_userauth_success(int type, u_int32_t seq, void *ctxt)
1.20 markus 320: {
321: Authctxt *authctxt = ctxt;
322: if (authctxt == NULL)
323: fatal("input_userauth_success: no authentication context");
1.51 markus 324: if (authctxt->authlist)
325: xfree(authctxt->authlist);
326: clear_auth_state(authctxt);
1.20 markus 327: authctxt->success = 1; /* break out */
328: }
329: void
1.92 markus 330: input_userauth_failure(int type, u_int32_t seq, void *ctxt)
1.20 markus 331: {
332: Authctxt *authctxt = ctxt;
333: char *authlist = NULL;
334: int partial;
335:
336: if (authctxt == NULL)
337: fatal("input_userauth_failure: no authentication context");
338:
1.23 markus 339: authlist = packet_get_string(NULL);
1.20 markus 340: partial = packet_get_char();
1.90 markus 341: packet_check_eom();
1.20 markus 342:
343: if (partial != 0)
1.45 markus 344: log("Authenticated with partial success.");
1.20 markus 345: debug("authentications that can continue: %s", authlist);
346:
1.51 markus 347: clear_auth_state(authctxt);
348: userauth(authctxt, authlist);
349: }
350: void
1.92 markus 351: input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
1.51 markus 352: {
353: Authctxt *authctxt = ctxt;
354: Key *key = NULL;
355: Buffer b;
1.95 ! markus 356: int pktype, alen, blen, sent = 0;
1.54 markus 357: char *pkalg, *pkblob, *fp;
1.51 markus 358:
359: if (authctxt == NULL)
360: fatal("input_userauth_pk_ok: no authentication context");
361: if (datafellows & SSH_BUG_PKOK) {
362: /* this is similar to SSH_BUG_PKAUTH */
363: debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
364: pkblob = packet_get_string(&blen);
365: buffer_init(&b);
366: buffer_append(&b, pkblob, blen);
367: pkalg = buffer_get_string(&b, &alen);
368: buffer_free(&b);
369: } else {
370: pkalg = packet_get_string(&alen);
371: pkblob = packet_get_string(&blen);
372: }
1.90 markus 373: packet_check_eom();
1.51 markus 374:
375: debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
376: pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
377:
378: do {
379: if (authctxt->last_key == NULL ||
380: authctxt->last_key_sign == NULL) {
381: debug("no last key or no sign cb");
382: break;
383: }
1.95 ! markus 384: if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
1.51 markus 385: debug("unknown pkalg %s", pkalg);
386: break;
387: }
388: if ((key = key_from_blob(pkblob, blen)) == NULL) {
389: debug("no key from blob. pkalg %s", pkalg);
1.95 ! markus 390: break;
! 391: }
! 392: if (key->type != pktype) {
! 393: error("input_userauth_pk_ok: type mismatch "
! 394: "for decoded key (received %d, expected %d)",
! 395: key->type, pktype);
1.51 markus 396: break;
397: }
1.54 markus 398: fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
399: debug2("input_userauth_pk_ok: fp %s", fp);
400: xfree(fp);
1.51 markus 401: if (!key_equal(key, authctxt->last_key)) {
402: debug("key != last_key");
1.20 markus 403: break;
404: }
1.51 markus 405: sent = sign_and_send_pubkey(authctxt, key,
406: authctxt->last_key_sign);
1.87 deraadt 407: } while (0);
1.51 markus 408:
409: if (key != NULL)
410: key_free(key);
411: xfree(pkalg);
412: xfree(pkblob);
413:
414: /* unregister */
415: clear_auth_state(authctxt);
416: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
417:
418: /* try another method if we did not send a packet*/
419: if (sent == 0)
420: userauth(authctxt, NULL);
421:
1.20 markus 422: }
423:
1.1 markus 424: int
1.23 markus 425: userauth_none(Authctxt *authctxt)
426: {
427: /* initial userauth request */
428: packet_start(SSH2_MSG_USERAUTH_REQUEST);
429: packet_put_cstring(authctxt->server_user);
430: packet_put_cstring(authctxt->service);
431: packet_put_cstring(authctxt->method->name);
432: packet_send();
433: return 1;
434: }
435:
436: int
1.20 markus 437: userauth_passwd(Authctxt *authctxt)
1.1 markus 438: {
1.6 markus 439: static int attempt = 0;
1.1 markus 440: char prompt[80];
441: char *password;
1.6 markus 442:
1.13 todd 443: if (attempt++ >= options.number_of_password_prompts)
1.6 markus 444: return 0;
1.13 todd 445:
1.87 deraadt 446: if (attempt != 1)
1.13 todd 447: error("Permission denied, please try again.");
1.1 markus 448:
1.43 itojun 449: snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1.20 markus 450: authctxt->server_user, authctxt->host);
1.1 markus 451: password = read_passphrase(prompt, 0);
452: packet_start(SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 453: packet_put_cstring(authctxt->server_user);
454: packet_put_cstring(authctxt->service);
1.23 markus 455: packet_put_cstring(authctxt->method->name);
1.1 markus 456: packet_put_char(0);
1.49 markus 457: packet_put_cstring(password);
1.1 markus 458: memset(password, 0, strlen(password));
459: xfree(password);
1.85 markus 460: packet_add_padding(64);
1.1 markus 461: packet_send();
462: return 1;
463: }
464:
1.79 stevesk 465: static void
1.51 markus 466: clear_auth_state(Authctxt *authctxt)
467: {
468: /* XXX clear authentication state */
469: if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
470: debug3("clear_auth_state: key_free %p", authctxt->last_key);
471: key_free(authctxt->last_key);
472: }
473: authctxt->last_key = NULL;
474: authctxt->last_key_hint = -2;
475: authctxt->last_key_sign = NULL;
476: }
477:
1.76 itojun 478: static int
1.20 markus 479: sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
1.1 markus 480: {
481: Buffer b;
1.32 markus 482: u_char *blob, *signature;
1.1 markus 483: int bloblen, slen;
1.14 markus 484: int skip = 0;
1.17 markus 485: int ret = -1;
1.23 markus 486: int have_sig = 1;
1.1 markus 487:
1.30 markus 488: debug3("sign_and_send_pubkey");
1.51 markus 489:
1.28 markus 490: if (key_to_blob(k, &blob, &bloblen) == 0) {
491: /* we cannot handle this key */
1.30 markus 492: debug3("sign_and_send_pubkey: cannot handle key");
1.28 markus 493: return 0;
494: }
1.1 markus 495: /* data to be signed */
496: buffer_init(&b);
1.26 markus 497: if (datafellows & SSH_OLD_SESSIONID) {
498: buffer_append(&b, session_id2, session_id2_len);
1.41 stevesk 499: skip = session_id2_len;
1.26 markus 500: } else {
1.14 markus 501: buffer_put_string(&b, session_id2, session_id2_len);
502: skip = buffer_len(&b);
503: }
1.1 markus 504: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 505: buffer_put_cstring(&b, authctxt->server_user);
1.10 markus 506: buffer_put_cstring(&b,
1.30 markus 507: datafellows & SSH_BUG_PKSERVICE ?
1.10 markus 508: "ssh-userauth" :
1.20 markus 509: authctxt->service);
1.30 markus 510: if (datafellows & SSH_BUG_PKAUTH) {
511: buffer_put_char(&b, have_sig);
512: } else {
513: buffer_put_cstring(&b, authctxt->method->name);
514: buffer_put_char(&b, have_sig);
1.41 stevesk 515: buffer_put_cstring(&b, key_ssh_name(k));
1.30 markus 516: }
1.1 markus 517: buffer_put_string(&b, blob, bloblen);
518:
519: /* generate signature */
1.51 markus 520: ret = (*sign_callback)(authctxt, k, &signature, &slen,
521: buffer_ptr(&b), buffer_len(&b));
1.17 markus 522: if (ret == -1) {
523: xfree(blob);
524: buffer_free(&b);
525: return 0;
526: }
1.28 markus 527: #ifdef DEBUG_PK
1.1 markus 528: buffer_dump(&b);
529: #endif
1.30 markus 530: if (datafellows & SSH_BUG_PKSERVICE) {
1.10 markus 531: buffer_clear(&b);
532: buffer_append(&b, session_id2, session_id2_len);
1.51 markus 533: skip = session_id2_len;
1.10 markus 534: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 535: buffer_put_cstring(&b, authctxt->server_user);
536: buffer_put_cstring(&b, authctxt->service);
1.23 markus 537: buffer_put_cstring(&b, authctxt->method->name);
538: buffer_put_char(&b, have_sig);
1.30 markus 539: if (!(datafellows & SSH_BUG_PKAUTH))
1.41 stevesk 540: buffer_put_cstring(&b, key_ssh_name(k));
1.10 markus 541: buffer_put_string(&b, blob, bloblen);
542: }
543: xfree(blob);
1.51 markus 544:
1.1 markus 545: /* append signature */
546: buffer_put_string(&b, signature, slen);
547: xfree(signature);
548:
549: /* skip session id and packet type */
1.14 markus 550: if (buffer_len(&b) < skip + 1)
1.20 markus 551: fatal("userauth_pubkey: internal error");
1.14 markus 552: buffer_consume(&b, skip + 1);
1.1 markus 553:
554: /* put remaining data from buffer into packet */
555: packet_start(SSH2_MSG_USERAUTH_REQUEST);
556: packet_put_raw(buffer_ptr(&b), buffer_len(&b));
557: buffer_free(&b);
558: packet_send();
1.17 markus 559:
560: return 1;
1.16 markus 561: }
562:
1.76 itojun 563: static int
1.51 markus 564: send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
565: int hint)
1.20 markus 566: {
1.51 markus 567: u_char *blob;
568: int bloblen, have_sig = 0;
1.20 markus 569:
1.51 markus 570: debug3("send_pubkey_test");
1.16 markus 571:
1.51 markus 572: if (key_to_blob(k, &blob, &bloblen) == 0) {
573: /* we cannot handle this key */
574: debug3("send_pubkey_test: cannot handle key");
1.16 markus 575: return 0;
576: }
1.51 markus 577: /* register callback for USERAUTH_PK_OK message */
578: authctxt->last_key_sign = sign_callback;
579: authctxt->last_key_hint = hint;
580: authctxt->last_key = k;
581: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
582:
583: packet_start(SSH2_MSG_USERAUTH_REQUEST);
584: packet_put_cstring(authctxt->server_user);
585: packet_put_cstring(authctxt->service);
586: packet_put_cstring(authctxt->method->name);
587: packet_put_char(have_sig);
588: if (!(datafellows & SSH_BUG_PKAUTH))
589: packet_put_cstring(key_ssh_name(k));
590: packet_put_string(blob, bloblen);
591: xfree(blob);
592: packet_send();
593: return 1;
594: }
595:
1.76 itojun 596: static Key *
1.51 markus 597: load_identity_file(char *filename)
598: {
599: Key *private;
600: char prompt[300], *passphrase;
1.56 markus 601: int quit, i;
1.52 markus 602: struct stat st;
1.16 markus 603:
1.52 markus 604: if (stat(filename, &st) < 0) {
605: debug3("no such identity: %s", filename);
606: return NULL;
607: }
1.56 markus 608: private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
609: if (private == NULL) {
610: if (options.batch_mode)
1.51 markus 611: return NULL;
1.16 markus 612: snprintf(prompt, sizeof prompt,
1.88 deraadt 613: "Enter passphrase for key '%.100s': ", filename);
1.20 markus 614: for (i = 0; i < options.number_of_password_prompts; i++) {
615: passphrase = read_passphrase(prompt, 0);
616: if (strcmp(passphrase, "") != 0) {
1.56 markus 617: private = key_load_private_type(KEY_UNSPEC, filename,
618: passphrase, NULL);
1.51 markus 619: quit = 0;
1.20 markus 620: } else {
621: debug2("no passphrase given, try next key");
1.51 markus 622: quit = 1;
1.20 markus 623: }
624: memset(passphrase, 0, strlen(passphrase));
625: xfree(passphrase);
1.56 markus 626: if (private != NULL || quit)
1.20 markus 627: break;
628: debug2("bad passphrase given, try again...");
1.16 markus 629: }
630: }
1.51 markus 631: return private;
632: }
633:
1.76 itojun 634: static int
1.51 markus 635: identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
636: u_char *data, int datalen)
637: {
638: Key *private;
639: int idx, ret;
640:
641: idx = authctxt->last_key_hint;
642: if (idx < 0)
643: return -1;
1.80 markus 644:
645: /* private key is stored in external hardware */
1.88 deraadt 646: if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
1.80 markus 647: return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
648:
1.51 markus 649: private = load_identity_file(options.identity_files[idx]);
650: if (private == NULL)
651: return -1;
652: ret = key_sign(private, sigp, lenp, data, datalen);
653: key_free(private);
1.17 markus 654: return ret;
655: }
656:
1.76 itojun 657: static int
658: agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
1.32 markus 659: u_char *data, int datalen)
1.17 markus 660: {
1.20 markus 661: return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
1.17 markus 662: }
663:
1.76 itojun 664: static int
665: key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
1.51 markus 666: u_char *data, int datalen)
667: {
1.67 markus 668: return key_sign(key, sigp, lenp, data, datalen);
1.51 markus 669: }
670:
1.76 itojun 671: static int
1.20 markus 672: userauth_pubkey_agent(Authctxt *authctxt)
1.17 markus 673: {
674: static int called = 0;
1.28 markus 675: int ret = 0;
1.17 markus 676: char *comment;
677: Key *k;
678:
679: if (called == 0) {
1.28 markus 680: if (ssh_get_num_identities(authctxt->agent, 2) == 0)
681: debug2("userauth_pubkey_agent: no keys at all");
1.20 markus 682: called = 1;
1.17 markus 683: }
1.28 markus 684: k = ssh_get_next_identity(authctxt->agent, &comment, 2);
1.20 markus 685: if (k == NULL) {
1.28 markus 686: debug2("userauth_pubkey_agent: no more keys");
687: } else {
1.51 markus 688: debug("userauth_pubkey_agent: testing agent key %s", comment);
1.28 markus 689: xfree(comment);
1.51 markus 690: ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
691: if (ret == 0)
692: key_free(k);
1.20 markus 693: }
1.28 markus 694: if (ret == 0)
695: debug2("userauth_pubkey_agent: no message sent");
1.17 markus 696: return ret;
1.1 markus 697: }
698:
1.20 markus 699: int
700: userauth_pubkey(Authctxt *authctxt)
701: {
702: static int idx = 0;
703: int sent = 0;
1.51 markus 704: Key *key;
705: char *filename;
1.20 markus 706:
1.28 markus 707: if (authctxt->agent != NULL) {
708: do {
709: sent = userauth_pubkey_agent(authctxt);
1.87 deraadt 710: } while (!sent && authctxt->agent->howmany > 0);
1.28 markus 711: }
712: while (!sent && idx < options.num_identity_files) {
1.51 markus 713: key = options.identity_keys[idx];
714: filename = options.identity_files[idx];
715: if (key == NULL) {
716: debug("try privkey: %s", filename);
717: key = load_identity_file(filename);
718: if (key != NULL) {
719: sent = sign_and_send_pubkey(authctxt, key,
720: key_sign_cb);
721: key_free(key);
722: }
723: } else if (key->type != KEY_RSA1) {
724: debug("try pubkey: %s", filename);
725: sent = send_pubkey_test(authctxt, key,
726: identity_sign_cb, idx);
727: }
1.28 markus 728: idx++;
729: }
1.20 markus 730: return sent;
731: }
732:
1.23 markus 733: /*
734: * Send userauth request message specifying keyboard-interactive method.
735: */
736: int
737: userauth_kbdint(Authctxt *authctxt)
738: {
739: static int attempt = 0;
740:
741: if (attempt++ >= options.number_of_password_prompts)
742: return 0;
1.82 markus 743: /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
744: if (attempt > 1 && !authctxt->info_req_seen) {
745: debug3("userauth_kbdint: disable: no info_req_seen");
746: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
747: return 0;
748: }
1.23 markus 749:
750: debug2("userauth_kbdint");
751: packet_start(SSH2_MSG_USERAUTH_REQUEST);
752: packet_put_cstring(authctxt->server_user);
753: packet_put_cstring(authctxt->service);
754: packet_put_cstring(authctxt->method->name);
755: packet_put_cstring(""); /* lang */
756: packet_put_cstring(options.kbd_interactive_devices ?
757: options.kbd_interactive_devices : "");
758: packet_send();
759:
760: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
761: return 1;
762: }
763:
764: /*
1.46 markus 765: * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1.23 markus 766: */
767: void
1.92 markus 768: input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1.23 markus 769: {
770: Authctxt *authctxt = ctxt;
1.46 markus 771: char *name, *inst, *lang, *prompt, *response;
1.32 markus 772: u_int num_prompts, i;
1.23 markus 773: int echo = 0;
774:
775: debug2("input_userauth_info_req");
776:
777: if (authctxt == NULL)
778: fatal("input_userauth_info_req: no authentication context");
1.82 markus 779:
780: authctxt->info_req_seen = 1;
1.23 markus 781:
782: name = packet_get_string(NULL);
783: inst = packet_get_string(NULL);
784: lang = packet_get_string(NULL);
785: if (strlen(name) > 0)
1.78 markus 786: log("%s", name);
1.23 markus 787: if (strlen(inst) > 0)
1.78 markus 788: log("%s", inst);
1.46 markus 789: xfree(name);
1.23 markus 790: xfree(inst);
1.46 markus 791: xfree(lang);
1.23 markus 792:
793: num_prompts = packet_get_int();
794: /*
795: * Begin to build info response packet based on prompts requested.
796: * We commit to providing the correct number of responses, so if
797: * further on we run into a problem that prevents this, we have to
798: * be sure and clean this up and send a correct error response.
799: */
800: packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
801: packet_put_int(num_prompts);
802:
1.73 markus 803: debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1.23 markus 804: for (i = 0; i < num_prompts; i++) {
805: prompt = packet_get_string(NULL);
806: echo = packet_get_char();
807:
1.77 markus 808: response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1.23 markus 809:
1.49 markus 810: packet_put_cstring(response);
1.23 markus 811: memset(response, 0, strlen(response));
812: xfree(response);
813: xfree(prompt);
814: }
1.90 markus 815: packet_check_eom(); /* done with parsing incoming message. */
1.23 markus 816:
1.85 markus 817: packet_add_padding(64);
1.23 markus 818: packet_send();
1.68 markus 819: }
820:
821: /*
822: * this will be move to an external program (ssh-keysign) ASAP. ssh-keysign
823: * will be setuid-root and the sbit can be removed from /usr/bin/ssh.
824: */
825: int
826: userauth_hostbased(Authctxt *authctxt)
827: {
828: Key *private = NULL;
829: Buffer b;
830: u_char *signature, *blob;
831: char *chost, *pkalg, *p;
1.72 markus 832: const char *service;
1.68 markus 833: u_int blen, slen;
1.71 markus 834: int ok, i, len, found = 0;
1.68 markus 835:
836: /* check for a useful key */
837: for (i = 0; i < authctxt->nkeys; i++) {
838: private = authctxt->keys[i];
839: if (private && private->type != KEY_RSA1) {
840: found = 1;
841: /* we take and free the key */
842: authctxt->keys[i] = NULL;
843: break;
844: }
845: }
846: if (!found) {
1.84 markus 847: debug("userauth_hostbased: no more client hostkeys");
1.68 markus 848: return 0;
849: }
850: if (key_to_blob(private, &blob, &blen) == 0) {
851: key_free(private);
852: return 0;
853: }
1.84 markus 854: /* figure out a name for the client host */
855: p = get_local_name(packet_get_connection_in());
856: if (p == NULL) {
857: error("userauth_hostbased: cannot get local ipaddr/name");
858: key_free(private);
859: return 0;
860: }
861: len = strlen(p) + 2;
862: chost = xmalloc(len);
863: strlcpy(chost, p, len);
864: strlcat(chost, ".", len);
865: debug2("userauth_hostbased: chost %s", chost);
866:
1.72 markus 867: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
868: authctxt->service;
1.68 markus 869: pkalg = xstrdup(key_ssh_name(private));
870: buffer_init(&b);
871: /* construct data */
1.72 markus 872: buffer_put_string(&b, session_id2, session_id2_len);
1.68 markus 873: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
874: buffer_put_cstring(&b, authctxt->server_user);
1.72 markus 875: buffer_put_cstring(&b, service);
1.68 markus 876: buffer_put_cstring(&b, authctxt->method->name);
877: buffer_put_cstring(&b, pkalg);
878: buffer_put_string(&b, blob, blen);
879: buffer_put_cstring(&b, chost);
880: buffer_put_cstring(&b, authctxt->local_user);
881: #ifdef DEBUG_PK
882: buffer_dump(&b);
883: #endif
884: ok = key_sign(private, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
885: key_free(private);
886: buffer_free(&b);
887: if (ok != 0) {
888: error("key_sign failed");
889: xfree(chost);
890: xfree(pkalg);
891: return 0;
892: }
893: packet_start(SSH2_MSG_USERAUTH_REQUEST);
894: packet_put_cstring(authctxt->server_user);
895: packet_put_cstring(authctxt->service);
896: packet_put_cstring(authctxt->method->name);
897: packet_put_cstring(pkalg);
898: packet_put_string(blob, blen);
899: packet_put_cstring(chost);
900: packet_put_cstring(authctxt->local_user);
901: packet_put_string(signature, slen);
902: memset(signature, 's', slen);
903: xfree(signature);
904: xfree(chost);
905: xfree(pkalg);
906:
907: packet_send();
908: return 1;
1.23 markus 909: }
1.20 markus 910:
911: /* find auth method */
912:
913: /*
914: * given auth method name, if configurable options permit this method fill
915: * in auth_ident field and return true, otherwise return false.
916: */
1.76 itojun 917: static int
1.20 markus 918: authmethod_is_enabled(Authmethod *method)
919: {
920: if (method == NULL)
921: return 0;
922: /* return false if options indicate this method is disabled */
923: if (method->enabled == NULL || *method->enabled == 0)
924: return 0;
925: /* return false if batch mode is enabled but method needs interactive mode */
926: if (method->batch_flag != NULL && *method->batch_flag != 0)
927: return 0;
928: return 1;
929: }
930:
1.76 itojun 931: static Authmethod *
1.20 markus 932: authmethod_lookup(const char *name)
1.1 markus 933: {
1.20 markus 934: Authmethod *method = NULL;
935: if (name != NULL)
936: for (method = authmethods; method->name != NULL; method++)
937: if (strcmp(name, method->name) == 0)
938: return method;
939: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
940: return NULL;
941: }
1.1 markus 942:
1.53 markus 943: /* XXX internal state */
944: static Authmethod *current = NULL;
945: static char *supported = NULL;
946: static char *preferred = NULL;
1.20 markus 947: /*
948: * Given the authentication method list sent by the server, return the
949: * next method we should try. If the server initially sends a nil list,
1.67 markus 950: * use a built-in default list.
1.41 stevesk 951: */
1.76 itojun 952: static Authmethod *
1.20 markus 953: authmethod_get(char *authlist)
954: {
1.53 markus 955:
956: char *name = NULL;
957: int next;
1.41 stevesk 958:
1.20 markus 959: /* Use a suitable default if we're passed a nil list. */
960: if (authlist == NULL || strlen(authlist) == 0)
1.53 markus 961: authlist = options.preferred_authentications;
1.20 markus 962:
1.53 markus 963: if (supported == NULL || strcmp(authlist, supported) != 0) {
964: debug3("start over, passed a different list %s", authlist);
965: if (supported != NULL)
966: xfree(supported);
967: supported = xstrdup(authlist);
968: preferred = options.preferred_authentications;
969: debug3("preferred %s", preferred);
970: current = NULL;
971: } else if (current != NULL && authmethod_is_enabled(current))
972: return current;
1.20 markus 973:
1.53 markus 974: for (;;) {
975: if ((name = match_list(preferred, supported, &next)) == NULL) {
976: debug("no more auth methods to try");
977: current = NULL;
978: return NULL;
979: }
980: preferred += next;
1.23 markus 981: debug3("authmethod_lookup %s", name);
1.53 markus 982: debug3("remaining preferred: %s", preferred);
983: if ((current = authmethod_lookup(name)) != NULL &&
984: authmethod_is_enabled(current)) {
1.23 markus 985: debug3("authmethod_is_enabled %s", name);
1.53 markus 986: debug("next auth method to try is %s", name);
987: return current;
1.23 markus 988: }
1.1 markus 989: }
1.53 markus 990: }
1.1 markus 991:
1.79 stevesk 992: static char *
1.53 markus 993: authmethods_get(void)
994: {
995: Authmethod *method = NULL;
1.93 markus 996: Buffer b;
997: char *list;
1.27 provos 998:
1.93 markus 999: buffer_init(&b);
1.53 markus 1000: for (method = authmethods; method->name != NULL; method++) {
1001: if (authmethod_is_enabled(method)) {
1.93 markus 1002: if (buffer_len(&b) > 0)
1003: buffer_append(&b, ",", 1);
1004: buffer_append(&b, method->name, strlen(method->name));
1.53 markus 1005: }
1006: }
1.93 markus 1007: buffer_append(&b, "\0", 1);
1008: list = xstrdup(buffer_ptr(&b));
1009: buffer_free(&b);
1010: return list;
1.1 markus 1011: }
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