Annotation of src/usr.bin/ssh/sshconnect2.c, Revision 1.88
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"
1.88 ! deraadt 26: RCSID("$OpenBSD: sshconnect2.c,v 1.87 2001/12/05 10:06:13 deraadt 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"
1.57 provos 48: #include "dh.h"
1.17 markus 49: #include "authfd.h"
1.37 markus 50: #include "log.h"
51: #include "readconf.h"
52: #include "readpass.h"
1.53 markus 53: #include "match.h"
1.61 markus 54: #include "dispatch.h"
1.68 markus 55: #include "canohost.h"
1.22 provos 56:
1.1 markus 57: /* import */
58: extern char *client_version_string;
59: extern char *server_version_string;
60: extern Options options;
61:
62: /*
63: * SSH2 key exchange
64: */
65:
1.32 markus 66: u_char *session_id2 = NULL;
1.1 markus 67: int session_id2_len = 0;
68:
1.61 markus 69: char *xxx_host;
70: struct sockaddr *xxx_hostaddr;
71:
1.63 markus 72: Kex *xxx_kex = NULL;
73:
1.76 itojun 74: static int
1.75 markus 75: verify_host_key_callback(Key *hostkey)
1.61 markus 76: {
1.75 markus 77: if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
1.83 markus 78: fatal("Host key verification failed.");
1.61 markus 79: return 0;
80: }
81:
1.1 markus 82: void
1.22 provos 83: ssh_kex2(char *host, struct sockaddr *hostaddr)
84: {
85: Kex *kex;
1.61 markus 86:
87: xxx_host = host;
88: xxx_hostaddr = hostaddr;
1.22 provos 89:
1.29 markus 90: if (options.ciphers == (char *)-1) {
91: log("No valid ciphers for protocol version 2 given, using defaults.");
92: options.ciphers = NULL;
1.24 markus 93: }
1.22 provos 94: if (options.ciphers != NULL) {
95: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
96: myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
97: }
1.60 stevesk 98: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
99: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
100: myproposal[PROPOSAL_ENC_ALGS_STOC] =
101: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1.22 provos 102: if (options.compression) {
1.47 markus 103: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.22 provos 104: myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
105: } else {
1.47 markus 106: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.22 provos 107: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1.47 markus 108: }
109: if (options.macs != NULL) {
110: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
111: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1.22 provos 112: }
1.70 markus 113: if (options.hostkeyalgorithms != NULL)
1.88 ! deraadt 114: myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
1.70 markus 115: options.hostkeyalgorithms;
1.22 provos 116:
1.65 markus 117: /* start key exchange */
1.64 markus 118: kex = kex_setup(myproposal);
1.61 markus 119: kex->client_version_string=client_version_string;
120: kex->server_version_string=server_version_string;
1.75 markus 121: kex->verify_host_key=&verify_host_key_callback;
1.63 markus 122:
123: xxx_kex = kex;
1.22 provos 124:
1.66 markus 125: dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1.62 markus 126:
127: session_id2 = kex->session_id;
128: session_id2_len = kex->session_id_len;
1.22 provos 129:
130: #ifdef DEBUG_KEXDH
131: /* send 1st encrypted/maced/compressed message */
132: packet_start(SSH2_MSG_IGNORE);
133: packet_put_cstring("markus");
134: packet_send();
135: packet_write_wait();
136: #endif
1.61 markus 137: debug("done: ssh_kex2.");
1.1 markus 138: }
1.11 markus 139:
1.1 markus 140: /*
141: * Authenticate user
142: */
1.20 markus 143:
144: typedef struct Authctxt Authctxt;
145: typedef struct Authmethod Authmethod;
146:
147: typedef int sign_cb_fn(
148: Authctxt *authctxt, Key *key,
1.32 markus 149: u_char **sigp, int *lenp, u_char *data, int datalen);
1.20 markus 150:
151: struct Authctxt {
152: const char *server_user;
1.68 markus 153: const char *local_user;
1.20 markus 154: const char *host;
155: const char *service;
1.23 markus 156: Authmethod *method;
1.20 markus 157: int success;
1.51 markus 158: char *authlist;
1.68 markus 159: /* pubkey */
1.51 markus 160: Key *last_key;
161: sign_cb_fn *last_key_sign;
162: int last_key_hint;
1.68 markus 163: AuthenticationConnection *agent;
164: /* hostbased */
165: Key **keys;
166: int nkeys;
1.82 markus 167: /* kbd-interactive */
168: int info_req_seen;
1.20 markus 169: };
170: struct Authmethod {
171: char *name; /* string to compare against server's list */
172: int (*userauth)(Authctxt *authctxt);
173: int *enabled; /* flag in option struct that enables method */
174: int *batch_flag; /* flag in option struct that disables method */
175: };
176:
1.86 itojun 177: void input_userauth_success(int, int, void *);
178: void input_userauth_failure(int, int, void *);
179: void input_userauth_banner(int, int, void *);
180: void input_userauth_error(int, int, void *);
181: void input_userauth_info_req(int, int, void *);
182: void input_userauth_pk_ok(int, int, void *);
183:
184: int userauth_none(Authctxt *);
185: int userauth_pubkey(Authctxt *);
186: int userauth_passwd(Authctxt *);
187: int userauth_kbdint(Authctxt *);
188: int userauth_hostbased(Authctxt *);
1.20 markus 189:
1.86 itojun 190: void userauth(Authctxt *, char *);
1.51 markus 191:
1.76 itojun 192: static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *);
193: static void clear_auth_state(Authctxt *);
194:
195: static Authmethod *authmethod_get(char *authlist);
196: static Authmethod *authmethod_lookup(const char *name);
197: static char *authmethods_get(void);
1.20 markus 198:
199: Authmethod authmethods[] = {
1.81 markus 200: {"hostbased",
201: userauth_hostbased,
202: &options.hostbased_authentication,
203: NULL},
1.20 markus 204: {"publickey",
205: userauth_pubkey,
1.28 markus 206: &options.pubkey_authentication,
1.20 markus 207: NULL},
1.81 markus 208: {"keyboard-interactive",
209: userauth_kbdint,
210: &options.kbd_interactive_authentication,
211: &options.batch_mode},
1.20 markus 212: {"password",
213: userauth_passwd,
214: &options.password_authentication,
1.23 markus 215: &options.batch_mode},
216: {"none",
217: userauth_none,
218: NULL,
219: NULL},
1.20 markus 220: {NULL, NULL, NULL, NULL}
221: };
222:
223: void
1.68 markus 224: ssh_userauth2(const char *local_user, const char *server_user, char *host,
225: Key **keys, int nkeys)
1.20 markus 226: {
227: Authctxt authctxt;
228: int type;
229: int plen;
1.39 markus 230:
1.73 markus 231: if (options.challenge_response_authentication)
1.39 markus 232: options.kbd_interactive_authentication = 1;
1.20 markus 233:
234: debug("send SSH2_MSG_SERVICE_REQUEST");
235: packet_start(SSH2_MSG_SERVICE_REQUEST);
236: packet_put_cstring("ssh-userauth");
237: packet_send();
238: packet_write_wait();
239: type = packet_read(&plen);
240: if (type != SSH2_MSG_SERVICE_ACCEPT) {
241: fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
242: }
243: if (packet_remaining() > 0) {
244: char *reply = packet_get_string(&plen);
245: debug("service_accept: %s", reply);
246: xfree(reply);
247: } else {
248: debug("buggy server: service_accept w/o service");
249: }
250: packet_done();
251: debug("got SSH2_MSG_SERVICE_ACCEPT");
252:
1.53 markus 253: if (options.preferred_authentications == NULL)
254: options.preferred_authentications = authmethods_get();
255:
1.20 markus 256: /* setup authentication context */
1.82 markus 257: memset(&authctxt, 0, sizeof(authctxt));
1.20 markus 258: authctxt.agent = ssh_get_authentication_connection();
259: authctxt.server_user = server_user;
1.68 markus 260: authctxt.local_user = local_user;
1.20 markus 261: authctxt.host = host;
262: authctxt.service = "ssh-connection"; /* service name */
263: authctxt.success = 0;
1.23 markus 264: authctxt.method = authmethod_lookup("none");
1.51 markus 265: authctxt.authlist = NULL;
1.68 markus 266: authctxt.keys = keys;
267: authctxt.nkeys = nkeys;
1.82 markus 268: authctxt.info_req_seen = 0;
1.23 markus 269: if (authctxt.method == NULL)
270: fatal("ssh_userauth2: internal error: cannot send userauth none request");
1.20 markus 271:
272: /* initial userauth request */
1.23 markus 273: userauth_none(&authctxt);
1.20 markus 274:
1.65 markus 275: dispatch_init(&input_userauth_error);
1.20 markus 276: dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
277: dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
1.35 markus 278: dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
1.20 markus 279: dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
280:
281: if (authctxt.agent != NULL)
282: ssh_close_authentication_connection(authctxt.agent);
283:
1.34 markus 284: debug("ssh-userauth2 successful: method %s", authctxt.method->name);
1.20 markus 285: }
286: void
1.51 markus 287: userauth(Authctxt *authctxt, char *authlist)
288: {
289: if (authlist == NULL) {
290: authlist = authctxt->authlist;
291: } else {
292: if (authctxt->authlist)
293: xfree(authctxt->authlist);
294: authctxt->authlist = authlist;
295: }
296: for (;;) {
297: Authmethod *method = authmethod_get(authlist);
298: if (method == NULL)
299: fatal("Permission denied (%s).", authlist);
300: authctxt->method = method;
301: if (method->userauth(authctxt) != 0) {
302: debug2("we sent a %s packet, wait for reply", method->name);
303: break;
304: } else {
305: debug2("we did not send a packet, disable method");
306: method->enabled = NULL;
307: }
308: }
309: }
310: void
1.20 markus 311: input_userauth_error(int type, int plen, void *ctxt)
312: {
1.35 markus 313: fatal("input_userauth_error: bad message during authentication: "
314: "type %d", type);
315: }
316: void
317: input_userauth_banner(int type, int plen, void *ctxt)
318: {
319: char *msg, *lang;
320: debug3("input_userauth_banner");
321: msg = packet_get_string(NULL);
322: lang = packet_get_string(NULL);
323: fprintf(stderr, "%s", msg);
324: xfree(msg);
325: xfree(lang);
1.20 markus 326: }
327: void
328: input_userauth_success(int type, int plen, void *ctxt)
329: {
330: Authctxt *authctxt = ctxt;
331: if (authctxt == NULL)
332: fatal("input_userauth_success: no authentication context");
1.51 markus 333: if (authctxt->authlist)
334: xfree(authctxt->authlist);
335: clear_auth_state(authctxt);
1.20 markus 336: authctxt->success = 1; /* break out */
337: }
338: void
339: input_userauth_failure(int type, int plen, void *ctxt)
340: {
341: Authctxt *authctxt = ctxt;
342: char *authlist = NULL;
343: int partial;
344:
345: if (authctxt == NULL)
346: fatal("input_userauth_failure: no authentication context");
347:
1.23 markus 348: authlist = packet_get_string(NULL);
1.20 markus 349: partial = packet_get_char();
350: packet_done();
351:
352: if (partial != 0)
1.45 markus 353: log("Authenticated with partial success.");
1.20 markus 354: debug("authentications that can continue: %s", authlist);
355:
1.51 markus 356: clear_auth_state(authctxt);
357: userauth(authctxt, authlist);
358: }
359: void
360: input_userauth_pk_ok(int type, int plen, void *ctxt)
361: {
362: Authctxt *authctxt = ctxt;
363: Key *key = NULL;
364: Buffer b;
1.69 markus 365: int alen, blen, sent = 0;
1.54 markus 366: char *pkalg, *pkblob, *fp;
1.51 markus 367:
368: if (authctxt == NULL)
369: fatal("input_userauth_pk_ok: no authentication context");
370: if (datafellows & SSH_BUG_PKOK) {
371: /* this is similar to SSH_BUG_PKAUTH */
372: debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
373: pkblob = packet_get_string(&blen);
374: buffer_init(&b);
375: buffer_append(&b, pkblob, blen);
376: pkalg = buffer_get_string(&b, &alen);
377: buffer_free(&b);
378: } else {
379: pkalg = packet_get_string(&alen);
380: pkblob = packet_get_string(&blen);
381: }
382: packet_done();
383:
384: debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
385: pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
386:
387: do {
388: if (authctxt->last_key == NULL ||
389: authctxt->last_key_sign == NULL) {
390: debug("no last key or no sign cb");
391: break;
392: }
1.69 markus 393: if (key_type_from_name(pkalg) == KEY_UNSPEC) {
1.51 markus 394: debug("unknown pkalg %s", pkalg);
395: break;
396: }
397: if ((key = key_from_blob(pkblob, blen)) == NULL) {
398: debug("no key from blob. pkalg %s", pkalg);
399: break;
400: }
1.54 markus 401: fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
402: debug2("input_userauth_pk_ok: fp %s", fp);
403: xfree(fp);
1.51 markus 404: if (!key_equal(key, authctxt->last_key)) {
405: debug("key != last_key");
1.20 markus 406: break;
407: }
1.51 markus 408: sent = sign_and_send_pubkey(authctxt, key,
409: authctxt->last_key_sign);
1.87 deraadt 410: } while (0);
1.51 markus 411:
412: if (key != NULL)
413: key_free(key);
414: xfree(pkalg);
415: xfree(pkblob);
416:
417: /* unregister */
418: clear_auth_state(authctxt);
419: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
420:
421: /* try another method if we did not send a packet*/
422: if (sent == 0)
423: userauth(authctxt, NULL);
424:
1.20 markus 425: }
426:
1.1 markus 427: int
1.23 markus 428: userauth_none(Authctxt *authctxt)
429: {
430: /* initial userauth request */
431: packet_start(SSH2_MSG_USERAUTH_REQUEST);
432: packet_put_cstring(authctxt->server_user);
433: packet_put_cstring(authctxt->service);
434: packet_put_cstring(authctxt->method->name);
435: packet_send();
436: return 1;
437: }
438:
439: int
1.20 markus 440: userauth_passwd(Authctxt *authctxt)
1.1 markus 441: {
1.6 markus 442: static int attempt = 0;
1.1 markus 443: char prompt[80];
444: char *password;
1.6 markus 445:
1.13 todd 446: if (attempt++ >= options.number_of_password_prompts)
1.6 markus 447: return 0;
1.13 todd 448:
1.87 deraadt 449: if (attempt != 1)
1.13 todd 450: error("Permission denied, please try again.");
1.1 markus 451:
1.43 itojun 452: snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1.20 markus 453: authctxt->server_user, authctxt->host);
1.1 markus 454: password = read_passphrase(prompt, 0);
455: packet_start(SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 456: packet_put_cstring(authctxt->server_user);
457: packet_put_cstring(authctxt->service);
1.23 markus 458: packet_put_cstring(authctxt->method->name);
1.1 markus 459: packet_put_char(0);
1.49 markus 460: packet_put_cstring(password);
1.1 markus 461: memset(password, 0, strlen(password));
462: xfree(password);
1.85 markus 463: packet_add_padding(64);
1.1 markus 464: packet_send();
465: return 1;
466: }
467:
1.79 stevesk 468: static void
1.51 markus 469: clear_auth_state(Authctxt *authctxt)
470: {
471: /* XXX clear authentication state */
472: if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
473: debug3("clear_auth_state: key_free %p", authctxt->last_key);
474: key_free(authctxt->last_key);
475: }
476: authctxt->last_key = NULL;
477: authctxt->last_key_hint = -2;
478: authctxt->last_key_sign = NULL;
479: }
480:
1.76 itojun 481: static int
1.20 markus 482: sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
1.1 markus 483: {
484: Buffer b;
1.32 markus 485: u_char *blob, *signature;
1.1 markus 486: int bloblen, slen;
1.14 markus 487: int skip = 0;
1.17 markus 488: int ret = -1;
1.23 markus 489: int have_sig = 1;
1.1 markus 490:
1.30 markus 491: debug3("sign_and_send_pubkey");
1.51 markus 492:
1.28 markus 493: if (key_to_blob(k, &blob, &bloblen) == 0) {
494: /* we cannot handle this key */
1.30 markus 495: debug3("sign_and_send_pubkey: cannot handle key");
1.28 markus 496: return 0;
497: }
1.1 markus 498: /* data to be signed */
499: buffer_init(&b);
1.26 markus 500: if (datafellows & SSH_OLD_SESSIONID) {
501: buffer_append(&b, session_id2, session_id2_len);
1.41 stevesk 502: skip = session_id2_len;
1.26 markus 503: } else {
1.14 markus 504: buffer_put_string(&b, session_id2, session_id2_len);
505: skip = buffer_len(&b);
506: }
1.1 markus 507: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 508: buffer_put_cstring(&b, authctxt->server_user);
1.10 markus 509: buffer_put_cstring(&b,
1.30 markus 510: datafellows & SSH_BUG_PKSERVICE ?
1.10 markus 511: "ssh-userauth" :
1.20 markus 512: authctxt->service);
1.30 markus 513: if (datafellows & SSH_BUG_PKAUTH) {
514: buffer_put_char(&b, have_sig);
515: } else {
516: buffer_put_cstring(&b, authctxt->method->name);
517: buffer_put_char(&b, have_sig);
1.41 stevesk 518: buffer_put_cstring(&b, key_ssh_name(k));
1.30 markus 519: }
1.1 markus 520: buffer_put_string(&b, blob, bloblen);
521:
522: /* generate signature */
1.51 markus 523: ret = (*sign_callback)(authctxt, k, &signature, &slen,
524: buffer_ptr(&b), buffer_len(&b));
1.17 markus 525: if (ret == -1) {
526: xfree(blob);
527: buffer_free(&b);
528: return 0;
529: }
1.28 markus 530: #ifdef DEBUG_PK
1.1 markus 531: buffer_dump(&b);
532: #endif
1.30 markus 533: if (datafellows & SSH_BUG_PKSERVICE) {
1.10 markus 534: buffer_clear(&b);
535: buffer_append(&b, session_id2, session_id2_len);
1.51 markus 536: skip = session_id2_len;
1.10 markus 537: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 538: buffer_put_cstring(&b, authctxt->server_user);
539: buffer_put_cstring(&b, authctxt->service);
1.23 markus 540: buffer_put_cstring(&b, authctxt->method->name);
541: buffer_put_char(&b, have_sig);
1.30 markus 542: if (!(datafellows & SSH_BUG_PKAUTH))
1.41 stevesk 543: buffer_put_cstring(&b, key_ssh_name(k));
1.10 markus 544: buffer_put_string(&b, blob, bloblen);
545: }
546: xfree(blob);
1.51 markus 547:
1.1 markus 548: /* append signature */
549: buffer_put_string(&b, signature, slen);
550: xfree(signature);
551:
552: /* skip session id and packet type */
1.14 markus 553: if (buffer_len(&b) < skip + 1)
1.20 markus 554: fatal("userauth_pubkey: internal error");
1.14 markus 555: buffer_consume(&b, skip + 1);
1.1 markus 556:
557: /* put remaining data from buffer into packet */
558: packet_start(SSH2_MSG_USERAUTH_REQUEST);
559: packet_put_raw(buffer_ptr(&b), buffer_len(&b));
560: buffer_free(&b);
561: packet_send();
1.17 markus 562:
563: return 1;
1.16 markus 564: }
565:
1.76 itojun 566: static int
1.51 markus 567: send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
568: int hint)
1.20 markus 569: {
1.51 markus 570: u_char *blob;
571: int bloblen, have_sig = 0;
1.20 markus 572:
1.51 markus 573: debug3("send_pubkey_test");
1.16 markus 574:
1.51 markus 575: if (key_to_blob(k, &blob, &bloblen) == 0) {
576: /* we cannot handle this key */
577: debug3("send_pubkey_test: cannot handle key");
1.16 markus 578: return 0;
579: }
1.51 markus 580: /* register callback for USERAUTH_PK_OK message */
581: authctxt->last_key_sign = sign_callback;
582: authctxt->last_key_hint = hint;
583: authctxt->last_key = k;
584: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
585:
586: packet_start(SSH2_MSG_USERAUTH_REQUEST);
587: packet_put_cstring(authctxt->server_user);
588: packet_put_cstring(authctxt->service);
589: packet_put_cstring(authctxt->method->name);
590: packet_put_char(have_sig);
591: if (!(datafellows & SSH_BUG_PKAUTH))
592: packet_put_cstring(key_ssh_name(k));
593: packet_put_string(blob, bloblen);
594: xfree(blob);
595: packet_send();
596: return 1;
597: }
598:
1.76 itojun 599: static Key *
1.51 markus 600: load_identity_file(char *filename)
601: {
602: Key *private;
603: char prompt[300], *passphrase;
1.56 markus 604: int quit, i;
1.52 markus 605: struct stat st;
1.16 markus 606:
1.52 markus 607: if (stat(filename, &st) < 0) {
608: debug3("no such identity: %s", filename);
609: return NULL;
610: }
1.56 markus 611: private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
612: if (private == NULL) {
613: if (options.batch_mode)
1.51 markus 614: return NULL;
1.16 markus 615: snprintf(prompt, sizeof prompt,
1.88 ! deraadt 616: "Enter passphrase for key '%.100s': ", filename);
1.20 markus 617: for (i = 0; i < options.number_of_password_prompts; i++) {
618: passphrase = read_passphrase(prompt, 0);
619: if (strcmp(passphrase, "") != 0) {
1.56 markus 620: private = key_load_private_type(KEY_UNSPEC, filename,
621: passphrase, NULL);
1.51 markus 622: quit = 0;
1.20 markus 623: } else {
624: debug2("no passphrase given, try next key");
1.51 markus 625: quit = 1;
1.20 markus 626: }
627: memset(passphrase, 0, strlen(passphrase));
628: xfree(passphrase);
1.56 markus 629: if (private != NULL || quit)
1.20 markus 630: break;
631: debug2("bad passphrase given, try again...");
1.16 markus 632: }
633: }
1.51 markus 634: return private;
635: }
636:
1.76 itojun 637: static int
1.51 markus 638: identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
639: u_char *data, int datalen)
640: {
641: Key *private;
642: int idx, ret;
643:
644: idx = authctxt->last_key_hint;
645: if (idx < 0)
646: return -1;
1.80 markus 647:
648: /* private key is stored in external hardware */
1.88 ! deraadt 649: if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
1.80 markus 650: return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
651:
1.51 markus 652: private = load_identity_file(options.identity_files[idx]);
653: if (private == NULL)
654: return -1;
655: ret = key_sign(private, sigp, lenp, data, datalen);
656: key_free(private);
1.17 markus 657: return ret;
658: }
659:
1.76 itojun 660: static int
661: agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
1.32 markus 662: u_char *data, int datalen)
1.17 markus 663: {
1.20 markus 664: return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
1.17 markus 665: }
666:
1.76 itojun 667: static int
668: key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
1.51 markus 669: u_char *data, int datalen)
670: {
1.67 markus 671: return key_sign(key, sigp, lenp, data, datalen);
1.51 markus 672: }
673:
1.76 itojun 674: static int
1.20 markus 675: userauth_pubkey_agent(Authctxt *authctxt)
1.17 markus 676: {
677: static int called = 0;
1.28 markus 678: int ret = 0;
1.17 markus 679: char *comment;
680: Key *k;
681:
682: if (called == 0) {
1.28 markus 683: if (ssh_get_num_identities(authctxt->agent, 2) == 0)
684: debug2("userauth_pubkey_agent: no keys at all");
1.20 markus 685: called = 1;
1.17 markus 686: }
1.28 markus 687: k = ssh_get_next_identity(authctxt->agent, &comment, 2);
1.20 markus 688: if (k == NULL) {
1.28 markus 689: debug2("userauth_pubkey_agent: no more keys");
690: } else {
1.51 markus 691: debug("userauth_pubkey_agent: testing agent key %s", comment);
1.28 markus 692: xfree(comment);
1.51 markus 693: ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
694: if (ret == 0)
695: key_free(k);
1.20 markus 696: }
1.28 markus 697: if (ret == 0)
698: debug2("userauth_pubkey_agent: no message sent");
1.17 markus 699: return ret;
1.1 markus 700: }
701:
1.20 markus 702: int
703: userauth_pubkey(Authctxt *authctxt)
704: {
705: static int idx = 0;
706: int sent = 0;
1.51 markus 707: Key *key;
708: char *filename;
1.20 markus 709:
1.28 markus 710: if (authctxt->agent != NULL) {
711: do {
712: sent = userauth_pubkey_agent(authctxt);
1.87 deraadt 713: } while (!sent && authctxt->agent->howmany > 0);
1.28 markus 714: }
715: while (!sent && idx < options.num_identity_files) {
1.51 markus 716: key = options.identity_keys[idx];
717: filename = options.identity_files[idx];
718: if (key == NULL) {
719: debug("try privkey: %s", filename);
720: key = load_identity_file(filename);
721: if (key != NULL) {
722: sent = sign_and_send_pubkey(authctxt, key,
723: key_sign_cb);
724: key_free(key);
725: }
726: } else if (key->type != KEY_RSA1) {
727: debug("try pubkey: %s", filename);
728: sent = send_pubkey_test(authctxt, key,
729: identity_sign_cb, idx);
730: }
1.28 markus 731: idx++;
732: }
1.20 markus 733: return sent;
734: }
735:
1.23 markus 736: /*
737: * Send userauth request message specifying keyboard-interactive method.
738: */
739: int
740: userauth_kbdint(Authctxt *authctxt)
741: {
742: static int attempt = 0;
743:
744: if (attempt++ >= options.number_of_password_prompts)
745: return 0;
1.82 markus 746: /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
747: if (attempt > 1 && !authctxt->info_req_seen) {
748: debug3("userauth_kbdint: disable: no info_req_seen");
749: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
750: return 0;
751: }
1.23 markus 752:
753: debug2("userauth_kbdint");
754: packet_start(SSH2_MSG_USERAUTH_REQUEST);
755: packet_put_cstring(authctxt->server_user);
756: packet_put_cstring(authctxt->service);
757: packet_put_cstring(authctxt->method->name);
758: packet_put_cstring(""); /* lang */
759: packet_put_cstring(options.kbd_interactive_devices ?
760: options.kbd_interactive_devices : "");
761: packet_send();
762:
763: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
764: return 1;
765: }
766:
767: /*
1.46 markus 768: * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1.23 markus 769: */
770: void
771: input_userauth_info_req(int type, int plen, void *ctxt)
772: {
773: Authctxt *authctxt = ctxt;
1.46 markus 774: char *name, *inst, *lang, *prompt, *response;
1.32 markus 775: u_int num_prompts, i;
1.23 markus 776: int echo = 0;
777:
778: debug2("input_userauth_info_req");
779:
780: if (authctxt == NULL)
781: fatal("input_userauth_info_req: no authentication context");
1.82 markus 782:
783: authctxt->info_req_seen = 1;
1.23 markus 784:
785: name = packet_get_string(NULL);
786: inst = packet_get_string(NULL);
787: lang = packet_get_string(NULL);
788: if (strlen(name) > 0)
1.78 markus 789: log("%s", name);
1.23 markus 790: if (strlen(inst) > 0)
1.78 markus 791: log("%s", inst);
1.46 markus 792: xfree(name);
1.23 markus 793: xfree(inst);
1.46 markus 794: xfree(lang);
1.23 markus 795:
796: num_prompts = packet_get_int();
797: /*
798: * Begin to build info response packet based on prompts requested.
799: * We commit to providing the correct number of responses, so if
800: * further on we run into a problem that prevents this, we have to
801: * be sure and clean this up and send a correct error response.
802: */
803: packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
804: packet_put_int(num_prompts);
805:
1.73 markus 806: debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1.23 markus 807: for (i = 0; i < num_prompts; i++) {
808: prompt = packet_get_string(NULL);
809: echo = packet_get_char();
810:
1.77 markus 811: response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1.23 markus 812:
1.49 markus 813: packet_put_cstring(response);
1.23 markus 814: memset(response, 0, strlen(response));
815: xfree(response);
816: xfree(prompt);
817: }
818: packet_done(); /* done with parsing incoming message. */
819:
1.85 markus 820: packet_add_padding(64);
1.23 markus 821: packet_send();
1.68 markus 822: }
823:
824: /*
825: * this will be move to an external program (ssh-keysign) ASAP. ssh-keysign
826: * will be setuid-root and the sbit can be removed from /usr/bin/ssh.
827: */
828: int
829: userauth_hostbased(Authctxt *authctxt)
830: {
831: Key *private = NULL;
832: Buffer b;
833: u_char *signature, *blob;
834: char *chost, *pkalg, *p;
1.72 markus 835: const char *service;
1.68 markus 836: u_int blen, slen;
1.71 markus 837: int ok, i, len, found = 0;
1.68 markus 838:
839: /* check for a useful key */
840: for (i = 0; i < authctxt->nkeys; i++) {
841: private = authctxt->keys[i];
842: if (private && private->type != KEY_RSA1) {
843: found = 1;
844: /* we take and free the key */
845: authctxt->keys[i] = NULL;
846: break;
847: }
848: }
849: if (!found) {
1.84 markus 850: debug("userauth_hostbased: no more client hostkeys");
1.68 markus 851: return 0;
852: }
853: if (key_to_blob(private, &blob, &blen) == 0) {
854: key_free(private);
855: return 0;
856: }
1.84 markus 857: /* figure out a name for the client host */
858: p = get_local_name(packet_get_connection_in());
859: if (p == NULL) {
860: error("userauth_hostbased: cannot get local ipaddr/name");
861: key_free(private);
862: return 0;
863: }
864: len = strlen(p) + 2;
865: chost = xmalloc(len);
866: strlcpy(chost, p, len);
867: strlcat(chost, ".", len);
868: debug2("userauth_hostbased: chost %s", chost);
869:
1.72 markus 870: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
871: authctxt->service;
1.68 markus 872: pkalg = xstrdup(key_ssh_name(private));
873: buffer_init(&b);
874: /* construct data */
1.72 markus 875: buffer_put_string(&b, session_id2, session_id2_len);
1.68 markus 876: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
877: buffer_put_cstring(&b, authctxt->server_user);
1.72 markus 878: buffer_put_cstring(&b, service);
1.68 markus 879: buffer_put_cstring(&b, authctxt->method->name);
880: buffer_put_cstring(&b, pkalg);
881: buffer_put_string(&b, blob, blen);
882: buffer_put_cstring(&b, chost);
883: buffer_put_cstring(&b, authctxt->local_user);
884: #ifdef DEBUG_PK
885: buffer_dump(&b);
886: #endif
887: ok = key_sign(private, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
888: key_free(private);
889: buffer_free(&b);
890: if (ok != 0) {
891: error("key_sign failed");
892: xfree(chost);
893: xfree(pkalg);
894: return 0;
895: }
896: packet_start(SSH2_MSG_USERAUTH_REQUEST);
897: packet_put_cstring(authctxt->server_user);
898: packet_put_cstring(authctxt->service);
899: packet_put_cstring(authctxt->method->name);
900: packet_put_cstring(pkalg);
901: packet_put_string(blob, blen);
902: packet_put_cstring(chost);
903: packet_put_cstring(authctxt->local_user);
904: packet_put_string(signature, slen);
905: memset(signature, 's', slen);
906: xfree(signature);
907: xfree(chost);
908: xfree(pkalg);
909:
910: packet_send();
911: return 1;
1.23 markus 912: }
1.20 markus 913:
914: /* find auth method */
915:
916: /*
917: * given auth method name, if configurable options permit this method fill
918: * in auth_ident field and return true, otherwise return false.
919: */
1.76 itojun 920: static int
1.20 markus 921: authmethod_is_enabled(Authmethod *method)
922: {
923: if (method == NULL)
924: return 0;
925: /* return false if options indicate this method is disabled */
926: if (method->enabled == NULL || *method->enabled == 0)
927: return 0;
928: /* return false if batch mode is enabled but method needs interactive mode */
929: if (method->batch_flag != NULL && *method->batch_flag != 0)
930: return 0;
931: return 1;
932: }
933:
1.76 itojun 934: static Authmethod *
1.20 markus 935: authmethod_lookup(const char *name)
1.1 markus 936: {
1.20 markus 937: Authmethod *method = NULL;
938: if (name != NULL)
939: for (method = authmethods; method->name != NULL; method++)
940: if (strcmp(name, method->name) == 0)
941: return method;
942: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
943: return NULL;
944: }
1.1 markus 945:
1.53 markus 946: /* XXX internal state */
947: static Authmethod *current = NULL;
948: static char *supported = NULL;
949: static char *preferred = NULL;
1.20 markus 950: /*
951: * Given the authentication method list sent by the server, return the
952: * next method we should try. If the server initially sends a nil list,
1.67 markus 953: * use a built-in default list.
1.41 stevesk 954: */
1.76 itojun 955: static Authmethod *
1.20 markus 956: authmethod_get(char *authlist)
957: {
1.53 markus 958:
959: char *name = NULL;
960: int next;
1.41 stevesk 961:
1.20 markus 962: /* Use a suitable default if we're passed a nil list. */
963: if (authlist == NULL || strlen(authlist) == 0)
1.53 markus 964: authlist = options.preferred_authentications;
1.20 markus 965:
1.53 markus 966: if (supported == NULL || strcmp(authlist, supported) != 0) {
967: debug3("start over, passed a different list %s", authlist);
968: if (supported != NULL)
969: xfree(supported);
970: supported = xstrdup(authlist);
971: preferred = options.preferred_authentications;
972: debug3("preferred %s", preferred);
973: current = NULL;
974: } else if (current != NULL && authmethod_is_enabled(current))
975: return current;
1.20 markus 976:
1.53 markus 977: for (;;) {
978: if ((name = match_list(preferred, supported, &next)) == NULL) {
979: debug("no more auth methods to try");
980: current = NULL;
981: return NULL;
982: }
983: preferred += next;
1.23 markus 984: debug3("authmethod_lookup %s", name);
1.53 markus 985: debug3("remaining preferred: %s", preferred);
986: if ((current = authmethod_lookup(name)) != NULL &&
987: authmethod_is_enabled(current)) {
1.23 markus 988: debug3("authmethod_is_enabled %s", name);
1.53 markus 989: debug("next auth method to try is %s", name);
990: return current;
1.23 markus 991: }
1.1 markus 992: }
1.53 markus 993: }
1.1 markus 994:
1.27 provos 995:
1.53 markus 996: #define DELIM ","
1.79 stevesk 997:
998: static char *
1.53 markus 999: authmethods_get(void)
1000: {
1001: Authmethod *method = NULL;
1002: char buf[1024];
1.27 provos 1003:
1.53 markus 1004: buf[0] = '\0';
1005: for (method = authmethods; method->name != NULL; method++) {
1006: if (authmethod_is_enabled(method)) {
1007: if (buf[0] != '\0')
1008: strlcat(buf, DELIM, sizeof buf);
1009: strlcat(buf, method->name, sizeof buf);
1010: }
1011: }
1012: return xstrdup(buf);
1.1 markus 1013: }
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