Annotation of src/usr.bin/ssh/sshconnect2.c, Revision 1.92
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"
1.92 ! markus 26: RCSID("$OpenBSD: sshconnect2.c,v 1.91 2001/12/28 14:50:54 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"
1.57 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:
1.92 ! markus 177: void input_userauth_success(int, u_int32_t, void *);
! 178: void input_userauth_failure(int, u_int32_t, void *);
! 179: void input_userauth_banner(int, u_int32_t, void *);
! 180: void input_userauth_error(int, u_int32_t, void *);
! 181: void input_userauth_info_req(int, u_int32_t, void *);
! 182: void input_userauth_pk_ok(int, u_int32_t, void *);
1.86 itojun 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;
1.39 markus 229:
1.73 markus 230: if (options.challenge_response_authentication)
1.39 markus 231: options.kbd_interactive_authentication = 1;
1.20 markus 232:
233: debug("send SSH2_MSG_SERVICE_REQUEST");
234: packet_start(SSH2_MSG_SERVICE_REQUEST);
235: packet_put_cstring("ssh-userauth");
236: packet_send();
237: packet_write_wait();
1.91 markus 238: type = packet_read();
1.20 markus 239: if (type != SSH2_MSG_SERVICE_ACCEPT) {
240: fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
241: }
242: if (packet_remaining() > 0) {
1.91 markus 243: char *reply = packet_get_string(NULL);
1.20 markus 244: debug("service_accept: %s", reply);
245: xfree(reply);
246: } else {
247: debug("buggy server: service_accept w/o service");
248: }
1.90 markus 249: packet_check_eom();
1.20 markus 250: debug("got SSH2_MSG_SERVICE_ACCEPT");
251:
1.53 markus 252: if (options.preferred_authentications == NULL)
253: options.preferred_authentications = authmethods_get();
254:
1.20 markus 255: /* setup authentication context */
1.82 markus 256: memset(&authctxt, 0, sizeof(authctxt));
1.20 markus 257: authctxt.agent = ssh_get_authentication_connection();
258: authctxt.server_user = server_user;
1.68 markus 259: authctxt.local_user = local_user;
1.20 markus 260: authctxt.host = host;
261: authctxt.service = "ssh-connection"; /* service name */
262: authctxt.success = 0;
1.23 markus 263: authctxt.method = authmethod_lookup("none");
1.51 markus 264: authctxt.authlist = NULL;
1.68 markus 265: authctxt.keys = keys;
266: authctxt.nkeys = nkeys;
1.82 markus 267: authctxt.info_req_seen = 0;
1.23 markus 268: if (authctxt.method == NULL)
269: fatal("ssh_userauth2: internal error: cannot send userauth none request");
1.20 markus 270:
271: /* initial userauth request */
1.23 markus 272: userauth_none(&authctxt);
1.20 markus 273:
1.65 markus 274: dispatch_init(&input_userauth_error);
1.20 markus 275: dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
276: dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
1.35 markus 277: dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
1.20 markus 278: dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
279:
280: if (authctxt.agent != NULL)
281: ssh_close_authentication_connection(authctxt.agent);
282:
1.34 markus 283: debug("ssh-userauth2 successful: method %s", authctxt.method->name);
1.20 markus 284: }
285: void
1.51 markus 286: userauth(Authctxt *authctxt, char *authlist)
287: {
288: if (authlist == NULL) {
289: authlist = authctxt->authlist;
290: } else {
291: if (authctxt->authlist)
292: xfree(authctxt->authlist);
293: authctxt->authlist = authlist;
294: }
295: for (;;) {
296: Authmethod *method = authmethod_get(authlist);
297: if (method == NULL)
298: fatal("Permission denied (%s).", authlist);
299: authctxt->method = method;
300: if (method->userauth(authctxt) != 0) {
301: debug2("we sent a %s packet, wait for reply", method->name);
302: break;
303: } else {
304: debug2("we did not send a packet, disable method");
305: method->enabled = NULL;
306: }
307: }
308: }
309: void
1.92 ! markus 310: input_userauth_error(int type, u_int32_t seq, void *ctxt)
1.20 markus 311: {
1.35 markus 312: fatal("input_userauth_error: bad message during authentication: "
313: "type %d", type);
314: }
315: void
1.92 ! markus 316: input_userauth_banner(int type, u_int32_t seq, void *ctxt)
1.35 markus 317: {
318: char *msg, *lang;
319: debug3("input_userauth_banner");
320: msg = packet_get_string(NULL);
321: lang = packet_get_string(NULL);
322: fprintf(stderr, "%s", msg);
323: xfree(msg);
324: xfree(lang);
1.20 markus 325: }
326: void
1.92 ! markus 327: input_userauth_success(int type, u_int32_t seq, void *ctxt)
1.20 markus 328: {
329: Authctxt *authctxt = ctxt;
330: if (authctxt == NULL)
331: fatal("input_userauth_success: no authentication context");
1.51 markus 332: if (authctxt->authlist)
333: xfree(authctxt->authlist);
334: clear_auth_state(authctxt);
1.20 markus 335: authctxt->success = 1; /* break out */
336: }
337: void
1.92 ! markus 338: input_userauth_failure(int type, u_int32_t seq, void *ctxt)
1.20 markus 339: {
340: Authctxt *authctxt = ctxt;
341: char *authlist = NULL;
342: int partial;
343:
344: if (authctxt == NULL)
345: fatal("input_userauth_failure: no authentication context");
346:
1.23 markus 347: authlist = packet_get_string(NULL);
1.20 markus 348: partial = packet_get_char();
1.90 markus 349: packet_check_eom();
1.20 markus 350:
351: if (partial != 0)
1.45 markus 352: log("Authenticated with partial success.");
1.20 markus 353: debug("authentications that can continue: %s", authlist);
354:
1.51 markus 355: clear_auth_state(authctxt);
356: userauth(authctxt, authlist);
357: }
358: void
1.92 ! markus 359: input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
1.51 markus 360: {
361: Authctxt *authctxt = ctxt;
362: Key *key = NULL;
363: Buffer b;
1.69 markus 364: int alen, blen, sent = 0;
1.54 markus 365: char *pkalg, *pkblob, *fp;
1.51 markus 366:
367: if (authctxt == NULL)
368: fatal("input_userauth_pk_ok: no authentication context");
369: if (datafellows & SSH_BUG_PKOK) {
370: /* this is similar to SSH_BUG_PKAUTH */
371: debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
372: pkblob = packet_get_string(&blen);
373: buffer_init(&b);
374: buffer_append(&b, pkblob, blen);
375: pkalg = buffer_get_string(&b, &alen);
376: buffer_free(&b);
377: } else {
378: pkalg = packet_get_string(&alen);
379: pkblob = packet_get_string(&blen);
380: }
1.90 markus 381: packet_check_eom();
1.51 markus 382:
383: debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
384: pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
385:
386: do {
387: if (authctxt->last_key == NULL ||
388: authctxt->last_key_sign == NULL) {
389: debug("no last key or no sign cb");
390: break;
391: }
1.69 markus 392: if (key_type_from_name(pkalg) == KEY_UNSPEC) {
1.51 markus 393: debug("unknown pkalg %s", pkalg);
394: break;
395: }
396: if ((key = key_from_blob(pkblob, blen)) == NULL) {
397: debug("no key from blob. pkalg %s", pkalg);
398: break;
399: }
1.54 markus 400: fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
401: debug2("input_userauth_pk_ok: fp %s", fp);
402: xfree(fp);
1.51 markus 403: if (!key_equal(key, authctxt->last_key)) {
404: debug("key != last_key");
1.20 markus 405: break;
406: }
1.51 markus 407: sent = sign_and_send_pubkey(authctxt, key,
408: authctxt->last_key_sign);
1.87 deraadt 409: } while (0);
1.51 markus 410:
411: if (key != NULL)
412: key_free(key);
413: xfree(pkalg);
414: xfree(pkblob);
415:
416: /* unregister */
417: clear_auth_state(authctxt);
418: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
419:
420: /* try another method if we did not send a packet*/
421: if (sent == 0)
422: userauth(authctxt, NULL);
423:
1.20 markus 424: }
425:
1.1 markus 426: int
1.23 markus 427: userauth_none(Authctxt *authctxt)
428: {
429: /* initial userauth request */
430: packet_start(SSH2_MSG_USERAUTH_REQUEST);
431: packet_put_cstring(authctxt->server_user);
432: packet_put_cstring(authctxt->service);
433: packet_put_cstring(authctxt->method->name);
434: packet_send();
435: return 1;
436: }
437:
438: int
1.20 markus 439: userauth_passwd(Authctxt *authctxt)
1.1 markus 440: {
1.6 markus 441: static int attempt = 0;
1.1 markus 442: char prompt[80];
443: char *password;
1.6 markus 444:
1.13 todd 445: if (attempt++ >= options.number_of_password_prompts)
1.6 markus 446: return 0;
1.13 todd 447:
1.87 deraadt 448: if (attempt != 1)
1.13 todd 449: error("Permission denied, please try again.");
1.1 markus 450:
1.43 itojun 451: snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1.20 markus 452: authctxt->server_user, authctxt->host);
1.1 markus 453: password = read_passphrase(prompt, 0);
454: packet_start(SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 455: packet_put_cstring(authctxt->server_user);
456: packet_put_cstring(authctxt->service);
1.23 markus 457: packet_put_cstring(authctxt->method->name);
1.1 markus 458: packet_put_char(0);
1.49 markus 459: packet_put_cstring(password);
1.1 markus 460: memset(password, 0, strlen(password));
461: xfree(password);
1.85 markus 462: packet_add_padding(64);
1.1 markus 463: packet_send();
464: return 1;
465: }
466:
1.79 stevesk 467: static void
1.51 markus 468: clear_auth_state(Authctxt *authctxt)
469: {
470: /* XXX clear authentication state */
471: if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
472: debug3("clear_auth_state: key_free %p", authctxt->last_key);
473: key_free(authctxt->last_key);
474: }
475: authctxt->last_key = NULL;
476: authctxt->last_key_hint = -2;
477: authctxt->last_key_sign = NULL;
478: }
479:
1.76 itojun 480: static int
1.20 markus 481: sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
1.1 markus 482: {
483: Buffer b;
1.32 markus 484: u_char *blob, *signature;
1.1 markus 485: int bloblen, slen;
1.14 markus 486: int skip = 0;
1.17 markus 487: int ret = -1;
1.23 markus 488: int have_sig = 1;
1.1 markus 489:
1.30 markus 490: debug3("sign_and_send_pubkey");
1.51 markus 491:
1.28 markus 492: if (key_to_blob(k, &blob, &bloblen) == 0) {
493: /* we cannot handle this key */
1.30 markus 494: debug3("sign_and_send_pubkey: cannot handle key");
1.28 markus 495: return 0;
496: }
1.1 markus 497: /* data to be signed */
498: buffer_init(&b);
1.26 markus 499: if (datafellows & SSH_OLD_SESSIONID) {
500: buffer_append(&b, session_id2, session_id2_len);
1.41 stevesk 501: skip = session_id2_len;
1.26 markus 502: } else {
1.14 markus 503: buffer_put_string(&b, session_id2, session_id2_len);
504: skip = buffer_len(&b);
505: }
1.1 markus 506: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 507: buffer_put_cstring(&b, authctxt->server_user);
1.10 markus 508: buffer_put_cstring(&b,
1.30 markus 509: datafellows & SSH_BUG_PKSERVICE ?
1.10 markus 510: "ssh-userauth" :
1.20 markus 511: authctxt->service);
1.30 markus 512: if (datafellows & SSH_BUG_PKAUTH) {
513: buffer_put_char(&b, have_sig);
514: } else {
515: buffer_put_cstring(&b, authctxt->method->name);
516: buffer_put_char(&b, have_sig);
1.41 stevesk 517: buffer_put_cstring(&b, key_ssh_name(k));
1.30 markus 518: }
1.1 markus 519: buffer_put_string(&b, blob, bloblen);
520:
521: /* generate signature */
1.51 markus 522: ret = (*sign_callback)(authctxt, k, &signature, &slen,
523: buffer_ptr(&b), buffer_len(&b));
1.17 markus 524: if (ret == -1) {
525: xfree(blob);
526: buffer_free(&b);
527: return 0;
528: }
1.28 markus 529: #ifdef DEBUG_PK
1.1 markus 530: buffer_dump(&b);
531: #endif
1.30 markus 532: if (datafellows & SSH_BUG_PKSERVICE) {
1.10 markus 533: buffer_clear(&b);
534: buffer_append(&b, session_id2, session_id2_len);
1.51 markus 535: skip = session_id2_len;
1.10 markus 536: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 537: buffer_put_cstring(&b, authctxt->server_user);
538: buffer_put_cstring(&b, authctxt->service);
1.23 markus 539: buffer_put_cstring(&b, authctxt->method->name);
540: buffer_put_char(&b, have_sig);
1.30 markus 541: if (!(datafellows & SSH_BUG_PKAUTH))
1.41 stevesk 542: buffer_put_cstring(&b, key_ssh_name(k));
1.10 markus 543: buffer_put_string(&b, blob, bloblen);
544: }
545: xfree(blob);
1.51 markus 546:
1.1 markus 547: /* append signature */
548: buffer_put_string(&b, signature, slen);
549: xfree(signature);
550:
551: /* skip session id and packet type */
1.14 markus 552: if (buffer_len(&b) < skip + 1)
1.20 markus 553: fatal("userauth_pubkey: internal error");
1.14 markus 554: buffer_consume(&b, skip + 1);
1.1 markus 555:
556: /* put remaining data from buffer into packet */
557: packet_start(SSH2_MSG_USERAUTH_REQUEST);
558: packet_put_raw(buffer_ptr(&b), buffer_len(&b));
559: buffer_free(&b);
560: packet_send();
1.17 markus 561:
562: return 1;
1.16 markus 563: }
564:
1.76 itojun 565: static int
1.51 markus 566: send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
567: int hint)
1.20 markus 568: {
1.51 markus 569: u_char *blob;
570: int bloblen, have_sig = 0;
1.20 markus 571:
1.51 markus 572: debug3("send_pubkey_test");
1.16 markus 573:
1.51 markus 574: if (key_to_blob(k, &blob, &bloblen) == 0) {
575: /* we cannot handle this key */
576: debug3("send_pubkey_test: cannot handle key");
1.16 markus 577: return 0;
578: }
1.51 markus 579: /* register callback for USERAUTH_PK_OK message */
580: authctxt->last_key_sign = sign_callback;
581: authctxt->last_key_hint = hint;
582: authctxt->last_key = k;
583: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
584:
585: packet_start(SSH2_MSG_USERAUTH_REQUEST);
586: packet_put_cstring(authctxt->server_user);
587: packet_put_cstring(authctxt->service);
588: packet_put_cstring(authctxt->method->name);
589: packet_put_char(have_sig);
590: if (!(datafellows & SSH_BUG_PKAUTH))
591: packet_put_cstring(key_ssh_name(k));
592: packet_put_string(blob, bloblen);
593: xfree(blob);
594: packet_send();
595: return 1;
596: }
597:
1.76 itojun 598: static Key *
1.51 markus 599: load_identity_file(char *filename)
600: {
601: Key *private;
602: char prompt[300], *passphrase;
1.56 markus 603: int quit, i;
1.52 markus 604: struct stat st;
1.16 markus 605:
1.52 markus 606: if (stat(filename, &st) < 0) {
607: debug3("no such identity: %s", filename);
608: return NULL;
609: }
1.56 markus 610: private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
611: if (private == NULL) {
612: if (options.batch_mode)
1.51 markus 613: return NULL;
1.16 markus 614: snprintf(prompt, sizeof prompt,
1.88 deraadt 615: "Enter passphrase for key '%.100s': ", filename);
1.20 markus 616: for (i = 0; i < options.number_of_password_prompts; i++) {
617: passphrase = read_passphrase(prompt, 0);
618: if (strcmp(passphrase, "") != 0) {
1.56 markus 619: private = key_load_private_type(KEY_UNSPEC, filename,
620: passphrase, NULL);
1.51 markus 621: quit = 0;
1.20 markus 622: } else {
623: debug2("no passphrase given, try next key");
1.51 markus 624: quit = 1;
1.20 markus 625: }
626: memset(passphrase, 0, strlen(passphrase));
627: xfree(passphrase);
1.56 markus 628: if (private != NULL || quit)
1.20 markus 629: break;
630: debug2("bad passphrase given, try again...");
1.16 markus 631: }
632: }
1.51 markus 633: return private;
634: }
635:
1.76 itojun 636: static int
1.51 markus 637: identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
638: u_char *data, int datalen)
639: {
640: Key *private;
641: int idx, ret;
642:
643: idx = authctxt->last_key_hint;
644: if (idx < 0)
645: return -1;
1.80 markus 646:
647: /* private key is stored in external hardware */
1.88 deraadt 648: if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
1.80 markus 649: return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
650:
1.51 markus 651: private = load_identity_file(options.identity_files[idx]);
652: if (private == NULL)
653: return -1;
654: ret = key_sign(private, sigp, lenp, data, datalen);
655: key_free(private);
1.17 markus 656: return ret;
657: }
658:
1.76 itojun 659: static int
660: agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
1.32 markus 661: u_char *data, int datalen)
1.17 markus 662: {
1.20 markus 663: return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
1.17 markus 664: }
665:
1.76 itojun 666: static int
667: key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
1.51 markus 668: u_char *data, int datalen)
669: {
1.67 markus 670: return key_sign(key, sigp, lenp, data, datalen);
1.51 markus 671: }
672:
1.76 itojun 673: static int
1.20 markus 674: userauth_pubkey_agent(Authctxt *authctxt)
1.17 markus 675: {
676: static int called = 0;
1.28 markus 677: int ret = 0;
1.17 markus 678: char *comment;
679: Key *k;
680:
681: if (called == 0) {
1.28 markus 682: if (ssh_get_num_identities(authctxt->agent, 2) == 0)
683: debug2("userauth_pubkey_agent: no keys at all");
1.20 markus 684: called = 1;
1.17 markus 685: }
1.28 markus 686: k = ssh_get_next_identity(authctxt->agent, &comment, 2);
1.20 markus 687: if (k == NULL) {
1.28 markus 688: debug2("userauth_pubkey_agent: no more keys");
689: } else {
1.51 markus 690: debug("userauth_pubkey_agent: testing agent key %s", comment);
1.28 markus 691: xfree(comment);
1.51 markus 692: ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
693: if (ret == 0)
694: key_free(k);
1.20 markus 695: }
1.28 markus 696: if (ret == 0)
697: debug2("userauth_pubkey_agent: no message sent");
1.17 markus 698: return ret;
1.1 markus 699: }
700:
1.20 markus 701: int
702: userauth_pubkey(Authctxt *authctxt)
703: {
704: static int idx = 0;
705: int sent = 0;
1.51 markus 706: Key *key;
707: char *filename;
1.20 markus 708:
1.28 markus 709: if (authctxt->agent != NULL) {
710: do {
711: sent = userauth_pubkey_agent(authctxt);
1.87 deraadt 712: } while (!sent && authctxt->agent->howmany > 0);
1.28 markus 713: }
714: while (!sent && idx < options.num_identity_files) {
1.51 markus 715: key = options.identity_keys[idx];
716: filename = options.identity_files[idx];
717: if (key == NULL) {
718: debug("try privkey: %s", filename);
719: key = load_identity_file(filename);
720: if (key != NULL) {
721: sent = sign_and_send_pubkey(authctxt, key,
722: key_sign_cb);
723: key_free(key);
724: }
725: } else if (key->type != KEY_RSA1) {
726: debug("try pubkey: %s", filename);
727: sent = send_pubkey_test(authctxt, key,
728: identity_sign_cb, idx);
729: }
1.28 markus 730: idx++;
731: }
1.20 markus 732: return sent;
733: }
734:
1.23 markus 735: /*
736: * Send userauth request message specifying keyboard-interactive method.
737: */
738: int
739: userauth_kbdint(Authctxt *authctxt)
740: {
741: static int attempt = 0;
742:
743: if (attempt++ >= options.number_of_password_prompts)
744: return 0;
1.82 markus 745: /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
746: if (attempt > 1 && !authctxt->info_req_seen) {
747: debug3("userauth_kbdint: disable: no info_req_seen");
748: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
749: return 0;
750: }
1.23 markus 751:
752: debug2("userauth_kbdint");
753: packet_start(SSH2_MSG_USERAUTH_REQUEST);
754: packet_put_cstring(authctxt->server_user);
755: packet_put_cstring(authctxt->service);
756: packet_put_cstring(authctxt->method->name);
757: packet_put_cstring(""); /* lang */
758: packet_put_cstring(options.kbd_interactive_devices ?
759: options.kbd_interactive_devices : "");
760: packet_send();
761:
762: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
763: return 1;
764: }
765:
766: /*
1.46 markus 767: * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1.23 markus 768: */
769: void
1.92 ! markus 770: input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1.23 markus 771: {
772: Authctxt *authctxt = ctxt;
1.46 markus 773: char *name, *inst, *lang, *prompt, *response;
1.32 markus 774: u_int num_prompts, i;
1.23 markus 775: int echo = 0;
776:
777: debug2("input_userauth_info_req");
778:
779: if (authctxt == NULL)
780: fatal("input_userauth_info_req: no authentication context");
1.82 markus 781:
782: authctxt->info_req_seen = 1;
1.23 markus 783:
784: name = packet_get_string(NULL);
785: inst = packet_get_string(NULL);
786: lang = packet_get_string(NULL);
787: if (strlen(name) > 0)
1.78 markus 788: log("%s", name);
1.23 markus 789: if (strlen(inst) > 0)
1.78 markus 790: log("%s", inst);
1.46 markus 791: xfree(name);
1.23 markus 792: xfree(inst);
1.46 markus 793: xfree(lang);
1.23 markus 794:
795: num_prompts = packet_get_int();
796: /*
797: * Begin to build info response packet based on prompts requested.
798: * We commit to providing the correct number of responses, so if
799: * further on we run into a problem that prevents this, we have to
800: * be sure and clean this up and send a correct error response.
801: */
802: packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
803: packet_put_int(num_prompts);
804:
1.73 markus 805: debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1.23 markus 806: for (i = 0; i < num_prompts; i++) {
807: prompt = packet_get_string(NULL);
808: echo = packet_get_char();
809:
1.77 markus 810: response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1.23 markus 811:
1.49 markus 812: packet_put_cstring(response);
1.23 markus 813: memset(response, 0, strlen(response));
814: xfree(response);
815: xfree(prompt);
816: }
1.90 markus 817: packet_check_eom(); /* done with parsing incoming message. */
1.23 markus 818:
1.85 markus 819: packet_add_padding(64);
1.23 markus 820: packet_send();
1.68 markus 821: }
822:
823: /*
824: * this will be move to an external program (ssh-keysign) ASAP. ssh-keysign
825: * will be setuid-root and the sbit can be removed from /usr/bin/ssh.
826: */
827: int
828: userauth_hostbased(Authctxt *authctxt)
829: {
830: Key *private = NULL;
831: Buffer b;
832: u_char *signature, *blob;
833: char *chost, *pkalg, *p;
1.72 markus 834: const char *service;
1.68 markus 835: u_int blen, slen;
1.71 markus 836: int ok, i, len, found = 0;
1.68 markus 837:
838: /* check for a useful key */
839: for (i = 0; i < authctxt->nkeys; i++) {
840: private = authctxt->keys[i];
841: if (private && private->type != KEY_RSA1) {
842: found = 1;
843: /* we take and free the key */
844: authctxt->keys[i] = NULL;
845: break;
846: }
847: }
848: if (!found) {
1.84 markus 849: debug("userauth_hostbased: no more client hostkeys");
1.68 markus 850: return 0;
851: }
852: if (key_to_blob(private, &blob, &blen) == 0) {
853: key_free(private);
854: return 0;
855: }
1.84 markus 856: /* figure out a name for the client host */
857: p = get_local_name(packet_get_connection_in());
858: if (p == NULL) {
859: error("userauth_hostbased: cannot get local ipaddr/name");
860: key_free(private);
861: return 0;
862: }
863: len = strlen(p) + 2;
864: chost = xmalloc(len);
865: strlcpy(chost, p, len);
866: strlcat(chost, ".", len);
867: debug2("userauth_hostbased: chost %s", chost);
868:
1.72 markus 869: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
870: authctxt->service;
1.68 markus 871: pkalg = xstrdup(key_ssh_name(private));
872: buffer_init(&b);
873: /* construct data */
1.72 markus 874: buffer_put_string(&b, session_id2, session_id2_len);
1.68 markus 875: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
876: buffer_put_cstring(&b, authctxt->server_user);
1.72 markus 877: buffer_put_cstring(&b, service);
1.68 markus 878: buffer_put_cstring(&b, authctxt->method->name);
879: buffer_put_cstring(&b, pkalg);
880: buffer_put_string(&b, blob, blen);
881: buffer_put_cstring(&b, chost);
882: buffer_put_cstring(&b, authctxt->local_user);
883: #ifdef DEBUG_PK
884: buffer_dump(&b);
885: #endif
886: ok = key_sign(private, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
887: key_free(private);
888: buffer_free(&b);
889: if (ok != 0) {
890: error("key_sign failed");
891: xfree(chost);
892: xfree(pkalg);
893: return 0;
894: }
895: packet_start(SSH2_MSG_USERAUTH_REQUEST);
896: packet_put_cstring(authctxt->server_user);
897: packet_put_cstring(authctxt->service);
898: packet_put_cstring(authctxt->method->name);
899: packet_put_cstring(pkalg);
900: packet_put_string(blob, blen);
901: packet_put_cstring(chost);
902: packet_put_cstring(authctxt->local_user);
903: packet_put_string(signature, slen);
904: memset(signature, 's', slen);
905: xfree(signature);
906: xfree(chost);
907: xfree(pkalg);
908:
909: packet_send();
910: return 1;
1.23 markus 911: }
1.20 markus 912:
913: /* find auth method */
914:
915: /*
916: * given auth method name, if configurable options permit this method fill
917: * in auth_ident field and return true, otherwise return false.
918: */
1.76 itojun 919: static int
1.20 markus 920: authmethod_is_enabled(Authmethod *method)
921: {
922: if (method == NULL)
923: return 0;
924: /* return false if options indicate this method is disabled */
925: if (method->enabled == NULL || *method->enabled == 0)
926: return 0;
927: /* return false if batch mode is enabled but method needs interactive mode */
928: if (method->batch_flag != NULL && *method->batch_flag != 0)
929: return 0;
930: return 1;
931: }
932:
1.76 itojun 933: static Authmethod *
1.20 markus 934: authmethod_lookup(const char *name)
1.1 markus 935: {
1.20 markus 936: Authmethod *method = NULL;
937: if (name != NULL)
938: for (method = authmethods; method->name != NULL; method++)
939: if (strcmp(name, method->name) == 0)
940: return method;
941: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
942: return NULL;
943: }
1.1 markus 944:
1.53 markus 945: /* XXX internal state */
946: static Authmethod *current = NULL;
947: static char *supported = NULL;
948: static char *preferred = NULL;
1.20 markus 949: /*
950: * Given the authentication method list sent by the server, return the
951: * next method we should try. If the server initially sends a nil list,
1.67 markus 952: * use a built-in default list.
1.41 stevesk 953: */
1.76 itojun 954: static Authmethod *
1.20 markus 955: authmethod_get(char *authlist)
956: {
1.53 markus 957:
958: char *name = NULL;
959: int next;
1.41 stevesk 960:
1.20 markus 961: /* Use a suitable default if we're passed a nil list. */
962: if (authlist == NULL || strlen(authlist) == 0)
1.53 markus 963: authlist = options.preferred_authentications;
1.20 markus 964:
1.53 markus 965: if (supported == NULL || strcmp(authlist, supported) != 0) {
966: debug3("start over, passed a different list %s", authlist);
967: if (supported != NULL)
968: xfree(supported);
969: supported = xstrdup(authlist);
970: preferred = options.preferred_authentications;
971: debug3("preferred %s", preferred);
972: current = NULL;
973: } else if (current != NULL && authmethod_is_enabled(current))
974: return current;
1.20 markus 975:
1.53 markus 976: for (;;) {
977: if ((name = match_list(preferred, supported, &next)) == NULL) {
978: debug("no more auth methods to try");
979: current = NULL;
980: return NULL;
981: }
982: preferred += next;
1.23 markus 983: debug3("authmethod_lookup %s", name);
1.53 markus 984: debug3("remaining preferred: %s", preferred);
985: if ((current = authmethod_lookup(name)) != NULL &&
986: authmethod_is_enabled(current)) {
1.23 markus 987: debug3("authmethod_is_enabled %s", name);
1.53 markus 988: debug("next auth method to try is %s", name);
989: return current;
1.23 markus 990: }
1.1 markus 991: }
1.53 markus 992: }
1.1 markus 993:
1.27 provos 994:
1.53 markus 995: #define DELIM ","
1.79 stevesk 996:
997: static char *
1.53 markus 998: authmethods_get(void)
999: {
1000: Authmethod *method = NULL;
1001: char buf[1024];
1.27 provos 1002:
1.53 markus 1003: buf[0] = '\0';
1004: for (method = authmethods; method->name != NULL; method++) {
1005: if (authmethod_is_enabled(method)) {
1006: if (buf[0] != '\0')
1007: strlcat(buf, DELIM, sizeof buf);
1008: strlcat(buf, method->name, sizeof buf);
1009: }
1010: }
1011: return xstrdup(buf);
1.1 markus 1012: }
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