Annotation of src/usr.bin/ssh/sshconnect2.c, Revision 1.99
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"
1.99 ! markus 26: RCSID("$OpenBSD: sshconnect2.c,v 1.98 2002/03/19 10:49:35 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,
1.96 markus 141: u_char **sigp, u_int *lenp, u_char *data, u_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 *);
1.99 ! markus 175: void input_userauth_passwd_changereq(int, u_int32_t, void *);
1.86 itojun 176:
177: int userauth_none(Authctxt *);
178: int userauth_pubkey(Authctxt *);
179: int userauth_passwd(Authctxt *);
180: int userauth_kbdint(Authctxt *);
181: int userauth_hostbased(Authctxt *);
1.20 markus 182:
1.86 itojun 183: void userauth(Authctxt *, char *);
1.51 markus 184:
1.76 itojun 185: static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *);
186: static void clear_auth_state(Authctxt *);
187:
188: static Authmethod *authmethod_get(char *authlist);
189: static Authmethod *authmethod_lookup(const char *name);
190: static char *authmethods_get(void);
1.20 markus 191:
192: Authmethod authmethods[] = {
1.81 markus 193: {"hostbased",
194: userauth_hostbased,
195: &options.hostbased_authentication,
196: NULL},
1.20 markus 197: {"publickey",
198: userauth_pubkey,
1.28 markus 199: &options.pubkey_authentication,
1.20 markus 200: NULL},
1.81 markus 201: {"keyboard-interactive",
202: userauth_kbdint,
203: &options.kbd_interactive_authentication,
204: &options.batch_mode},
1.20 markus 205: {"password",
206: userauth_passwd,
207: &options.password_authentication,
1.23 markus 208: &options.batch_mode},
209: {"none",
210: userauth_none,
211: NULL,
212: NULL},
1.20 markus 213: {NULL, NULL, NULL, NULL}
214: };
215:
216: void
1.68 markus 217: ssh_userauth2(const char *local_user, const char *server_user, char *host,
218: Key **keys, int nkeys)
1.20 markus 219: {
220: Authctxt authctxt;
221: int type;
1.39 markus 222:
1.73 markus 223: if (options.challenge_response_authentication)
1.39 markus 224: options.kbd_interactive_authentication = 1;
1.20 markus 225:
226: debug("send SSH2_MSG_SERVICE_REQUEST");
227: packet_start(SSH2_MSG_SERVICE_REQUEST);
228: packet_put_cstring("ssh-userauth");
229: packet_send();
230: packet_write_wait();
1.91 markus 231: type = packet_read();
1.20 markus 232: if (type != SSH2_MSG_SERVICE_ACCEPT) {
233: fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
234: }
235: if (packet_remaining() > 0) {
1.91 markus 236: char *reply = packet_get_string(NULL);
1.20 markus 237: debug("service_accept: %s", reply);
238: xfree(reply);
239: } else {
240: debug("buggy server: service_accept w/o service");
241: }
1.90 markus 242: packet_check_eom();
1.20 markus 243: debug("got SSH2_MSG_SERVICE_ACCEPT");
244:
1.53 markus 245: if (options.preferred_authentications == NULL)
246: options.preferred_authentications = authmethods_get();
247:
1.20 markus 248: /* setup authentication context */
1.82 markus 249: memset(&authctxt, 0, sizeof(authctxt));
1.20 markus 250: authctxt.agent = ssh_get_authentication_connection();
251: authctxt.server_user = server_user;
1.68 markus 252: authctxt.local_user = local_user;
1.20 markus 253: authctxt.host = host;
254: authctxt.service = "ssh-connection"; /* service name */
255: authctxt.success = 0;
1.23 markus 256: authctxt.method = authmethod_lookup("none");
1.51 markus 257: authctxt.authlist = NULL;
1.68 markus 258: authctxt.keys = keys;
259: authctxt.nkeys = nkeys;
1.82 markus 260: authctxt.info_req_seen = 0;
1.23 markus 261: if (authctxt.method == NULL)
262: fatal("ssh_userauth2: internal error: cannot send userauth none request");
1.20 markus 263:
264: /* initial userauth request */
1.23 markus 265: userauth_none(&authctxt);
1.20 markus 266:
1.65 markus 267: dispatch_init(&input_userauth_error);
1.20 markus 268: dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
269: dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
1.35 markus 270: dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
1.20 markus 271: dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
272:
273: if (authctxt.agent != NULL)
274: ssh_close_authentication_connection(authctxt.agent);
275:
1.34 markus 276: debug("ssh-userauth2 successful: method %s", authctxt.method->name);
1.20 markus 277: }
278: void
1.51 markus 279: userauth(Authctxt *authctxt, char *authlist)
280: {
281: if (authlist == NULL) {
282: authlist = authctxt->authlist;
283: } else {
284: if (authctxt->authlist)
285: xfree(authctxt->authlist);
286: authctxt->authlist = authlist;
287: }
288: for (;;) {
289: Authmethod *method = authmethod_get(authlist);
290: if (method == NULL)
291: fatal("Permission denied (%s).", authlist);
292: authctxt->method = method;
293: if (method->userauth(authctxt) != 0) {
294: debug2("we sent a %s packet, wait for reply", method->name);
295: break;
296: } else {
297: debug2("we did not send a packet, disable method");
298: method->enabled = NULL;
299: }
300: }
301: }
302: void
1.92 markus 303: input_userauth_error(int type, u_int32_t seq, void *ctxt)
1.20 markus 304: {
1.35 markus 305: fatal("input_userauth_error: bad message during authentication: "
306: "type %d", type);
307: }
308: void
1.92 markus 309: input_userauth_banner(int type, u_int32_t seq, void *ctxt)
1.35 markus 310: {
311: char *msg, *lang;
312: debug3("input_userauth_banner");
313: msg = packet_get_string(NULL);
314: lang = packet_get_string(NULL);
315: fprintf(stderr, "%s", msg);
316: xfree(msg);
317: xfree(lang);
1.20 markus 318: }
319: void
1.92 markus 320: input_userauth_success(int type, u_int32_t seq, void *ctxt)
1.20 markus 321: {
322: Authctxt *authctxt = ctxt;
323: if (authctxt == NULL)
324: fatal("input_userauth_success: no authentication context");
1.51 markus 325: if (authctxt->authlist)
326: xfree(authctxt->authlist);
327: clear_auth_state(authctxt);
1.20 markus 328: authctxt->success = 1; /* break out */
329: }
330: void
1.92 markus 331: input_userauth_failure(int type, u_int32_t seq, void *ctxt)
1.20 markus 332: {
333: Authctxt *authctxt = ctxt;
334: char *authlist = NULL;
335: int partial;
336:
337: if (authctxt == NULL)
338: fatal("input_userauth_failure: no authentication context");
339:
1.23 markus 340: authlist = packet_get_string(NULL);
1.20 markus 341: partial = packet_get_char();
1.90 markus 342: packet_check_eom();
1.20 markus 343:
344: if (partial != 0)
1.45 markus 345: log("Authenticated with partial success.");
1.20 markus 346: debug("authentications that can continue: %s", authlist);
347:
1.51 markus 348: clear_auth_state(authctxt);
349: userauth(authctxt, authlist);
350: }
351: void
1.92 markus 352: input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
1.51 markus 353: {
354: Authctxt *authctxt = ctxt;
355: Key *key = NULL;
356: Buffer b;
1.96 markus 357: int pktype, sent = 0;
358: u_int alen, blen;
359: char *pkalg, *fp;
360: u_char *pkblob;
1.51 markus 361:
362: if (authctxt == NULL)
363: fatal("input_userauth_pk_ok: no authentication context");
364: if (datafellows & SSH_BUG_PKOK) {
365: /* this is similar to SSH_BUG_PKAUTH */
366: debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
367: pkblob = packet_get_string(&blen);
368: buffer_init(&b);
369: buffer_append(&b, pkblob, blen);
370: pkalg = buffer_get_string(&b, &alen);
371: buffer_free(&b);
372: } else {
373: pkalg = packet_get_string(&alen);
374: pkblob = packet_get_string(&blen);
375: }
1.90 markus 376: packet_check_eom();
1.51 markus 377:
378: debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
379: pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
380:
381: do {
382: if (authctxt->last_key == NULL ||
383: authctxt->last_key_sign == NULL) {
384: debug("no last key or no sign cb");
385: break;
386: }
1.95 markus 387: if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
1.51 markus 388: debug("unknown pkalg %s", pkalg);
389: break;
390: }
391: if ((key = key_from_blob(pkblob, blen)) == NULL) {
392: debug("no key from blob. pkalg %s", pkalg);
1.95 markus 393: break;
394: }
1.98 markus 395: if (key->type != pktype) {
1.95 markus 396: error("input_userauth_pk_ok: type mismatch "
397: "for decoded key (received %d, expected %d)",
398: key->type, pktype);
1.51 markus 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;
1.99 ! markus 443: char prompt[150];
1.1 markus 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();
1.99 ! markus 465:
! 466: dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
! 467: &input_userauth_passwd_changereq);
! 468:
1.1 markus 469: return 1;
470: }
1.99 ! markus 471: /*
! 472: * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
! 473: */
! 474: void
! 475: input_userauth_passwd_changereq(int type, uint32_t seqnr, void *ctxt)
! 476: {
! 477: Authctxt *authctxt = ctxt;
! 478: char *info, *lang, *password = NULL, *retype = NULL;
! 479: char prompt[150];
! 480:
! 481: debug2("input_userauth_passwd_changereq");
! 482:
! 483: if (authctxt == NULL)
! 484: fatal("input_userauth_passwd_changereq: "
! 485: "no authentication context");
! 486:
! 487: info = packet_get_string(NULL);
! 488: lang = packet_get_string(NULL);
! 489: if (strlen(info) > 0)
! 490: log("%s", info);
! 491: xfree(info);
! 492: xfree(lang);
! 493: packet_start(SSH2_MSG_USERAUTH_REQUEST);
! 494: packet_put_cstring(authctxt->server_user);
! 495: packet_put_cstring(authctxt->service);
! 496: packet_put_cstring(authctxt->method->name);
! 497: packet_put_char(1); /* additional info */
! 498: snprintf(prompt, sizeof(prompt),
! 499: "Enter %.30s@%.128s's old password: ",
! 500: authctxt->server_user, authctxt->host);
! 501: password = read_passphrase(prompt, 0);
! 502: packet_put_cstring(password);
! 503: memset(password, 0, strlen(password));
! 504: xfree(password);
! 505: password = NULL;
! 506: while (password == NULL) {
! 507: snprintf(prompt, sizeof(prompt),
! 508: "Enter %.30s@%.128s's new password: ",
! 509: authctxt->server_user, authctxt->host);
! 510: password = read_passphrase(prompt, RP_ALLOW_EOF);
! 511: if (password == NULL) {
! 512: /* bail out */
! 513: return;
! 514: }
! 515: snprintf(prompt, sizeof(prompt),
! 516: "Retype %.30s@%.128s's new password: ",
! 517: authctxt->server_user, authctxt->host);
! 518: retype = read_passphrase(prompt, 0);
! 519: if (strcmp(password, retype) != 0) {
! 520: memset(password, 0, strlen(password));
! 521: xfree(password);
! 522: log("Mismatch; try again, EOF to quit.");
! 523: password = NULL;
! 524: }
! 525: memset(retype, 0, strlen(retype));
! 526: xfree(retype);
! 527: }
! 528: packet_put_cstring(password);
! 529: memset(password, 0, strlen(password));
! 530: xfree(password);
! 531: packet_add_padding(64);
! 532: packet_send();
! 533:
! 534: dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
! 535: &input_userauth_passwd_changereq);
! 536: }
1.1 markus 537:
1.79 stevesk 538: static void
1.51 markus 539: clear_auth_state(Authctxt *authctxt)
540: {
541: /* XXX clear authentication state */
1.99 ! markus 542: dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, NULL);
! 543:
1.51 markus 544: if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
545: debug3("clear_auth_state: key_free %p", authctxt->last_key);
546: key_free(authctxt->last_key);
547: }
548: authctxt->last_key = NULL;
549: authctxt->last_key_hint = -2;
550: authctxt->last_key_sign = NULL;
551: }
552:
1.76 itojun 553: static int
1.20 markus 554: sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
1.1 markus 555: {
556: Buffer b;
1.32 markus 557: u_char *blob, *signature;
1.96 markus 558: u_int bloblen, slen;
1.14 markus 559: int skip = 0;
1.17 markus 560: int ret = -1;
1.23 markus 561: int have_sig = 1;
1.1 markus 562:
1.30 markus 563: debug3("sign_and_send_pubkey");
1.51 markus 564:
1.28 markus 565: if (key_to_blob(k, &blob, &bloblen) == 0) {
566: /* we cannot handle this key */
1.30 markus 567: debug3("sign_and_send_pubkey: cannot handle key");
1.28 markus 568: return 0;
569: }
1.1 markus 570: /* data to be signed */
571: buffer_init(&b);
1.26 markus 572: if (datafellows & SSH_OLD_SESSIONID) {
573: buffer_append(&b, session_id2, session_id2_len);
1.41 stevesk 574: skip = session_id2_len;
1.26 markus 575: } else {
1.14 markus 576: buffer_put_string(&b, session_id2, session_id2_len);
577: skip = buffer_len(&b);
578: }
1.1 markus 579: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 580: buffer_put_cstring(&b, authctxt->server_user);
1.10 markus 581: buffer_put_cstring(&b,
1.30 markus 582: datafellows & SSH_BUG_PKSERVICE ?
1.10 markus 583: "ssh-userauth" :
1.20 markus 584: authctxt->service);
1.30 markus 585: if (datafellows & SSH_BUG_PKAUTH) {
586: buffer_put_char(&b, have_sig);
587: } else {
588: buffer_put_cstring(&b, authctxt->method->name);
589: buffer_put_char(&b, have_sig);
1.41 stevesk 590: buffer_put_cstring(&b, key_ssh_name(k));
1.30 markus 591: }
1.1 markus 592: buffer_put_string(&b, blob, bloblen);
593:
594: /* generate signature */
1.51 markus 595: ret = (*sign_callback)(authctxt, k, &signature, &slen,
596: buffer_ptr(&b), buffer_len(&b));
1.17 markus 597: if (ret == -1) {
598: xfree(blob);
599: buffer_free(&b);
600: return 0;
601: }
1.28 markus 602: #ifdef DEBUG_PK
1.1 markus 603: buffer_dump(&b);
604: #endif
1.30 markus 605: if (datafellows & SSH_BUG_PKSERVICE) {
1.10 markus 606: buffer_clear(&b);
607: buffer_append(&b, session_id2, session_id2_len);
1.51 markus 608: skip = session_id2_len;
1.10 markus 609: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 610: buffer_put_cstring(&b, authctxt->server_user);
611: buffer_put_cstring(&b, authctxt->service);
1.23 markus 612: buffer_put_cstring(&b, authctxt->method->name);
613: buffer_put_char(&b, have_sig);
1.30 markus 614: if (!(datafellows & SSH_BUG_PKAUTH))
1.41 stevesk 615: buffer_put_cstring(&b, key_ssh_name(k));
1.10 markus 616: buffer_put_string(&b, blob, bloblen);
617: }
618: xfree(blob);
1.51 markus 619:
1.1 markus 620: /* append signature */
621: buffer_put_string(&b, signature, slen);
622: xfree(signature);
623:
624: /* skip session id and packet type */
1.14 markus 625: if (buffer_len(&b) < skip + 1)
1.20 markus 626: fatal("userauth_pubkey: internal error");
1.14 markus 627: buffer_consume(&b, skip + 1);
1.1 markus 628:
629: /* put remaining data from buffer into packet */
630: packet_start(SSH2_MSG_USERAUTH_REQUEST);
631: packet_put_raw(buffer_ptr(&b), buffer_len(&b));
632: buffer_free(&b);
633: packet_send();
1.17 markus 634:
635: return 1;
1.16 markus 636: }
637:
1.76 itojun 638: static int
1.51 markus 639: send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
640: int hint)
1.20 markus 641: {
1.51 markus 642: u_char *blob;
1.97 markus 643: u_int bloblen, have_sig = 0;
1.20 markus 644:
1.51 markus 645: debug3("send_pubkey_test");
1.16 markus 646:
1.51 markus 647: if (key_to_blob(k, &blob, &bloblen) == 0) {
648: /* we cannot handle this key */
649: debug3("send_pubkey_test: cannot handle key");
1.16 markus 650: return 0;
651: }
1.51 markus 652: /* register callback for USERAUTH_PK_OK message */
653: authctxt->last_key_sign = sign_callback;
654: authctxt->last_key_hint = hint;
655: authctxt->last_key = k;
656: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
657:
658: packet_start(SSH2_MSG_USERAUTH_REQUEST);
659: packet_put_cstring(authctxt->server_user);
660: packet_put_cstring(authctxt->service);
661: packet_put_cstring(authctxt->method->name);
662: packet_put_char(have_sig);
663: if (!(datafellows & SSH_BUG_PKAUTH))
664: packet_put_cstring(key_ssh_name(k));
665: packet_put_string(blob, bloblen);
666: xfree(blob);
667: packet_send();
668: return 1;
669: }
670:
1.76 itojun 671: static Key *
1.51 markus 672: load_identity_file(char *filename)
673: {
674: Key *private;
675: char prompt[300], *passphrase;
1.56 markus 676: int quit, i;
1.52 markus 677: struct stat st;
1.16 markus 678:
1.52 markus 679: if (stat(filename, &st) < 0) {
680: debug3("no such identity: %s", filename);
681: return NULL;
682: }
1.56 markus 683: private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
684: if (private == NULL) {
685: if (options.batch_mode)
1.51 markus 686: return NULL;
1.16 markus 687: snprintf(prompt, sizeof prompt,
1.88 deraadt 688: "Enter passphrase for key '%.100s': ", filename);
1.20 markus 689: for (i = 0; i < options.number_of_password_prompts; i++) {
690: passphrase = read_passphrase(prompt, 0);
691: if (strcmp(passphrase, "") != 0) {
1.56 markus 692: private = key_load_private_type(KEY_UNSPEC, filename,
693: passphrase, NULL);
1.51 markus 694: quit = 0;
1.20 markus 695: } else {
696: debug2("no passphrase given, try next key");
1.51 markus 697: quit = 1;
1.20 markus 698: }
699: memset(passphrase, 0, strlen(passphrase));
700: xfree(passphrase);
1.56 markus 701: if (private != NULL || quit)
1.20 markus 702: break;
703: debug2("bad passphrase given, try again...");
1.16 markus 704: }
705: }
1.51 markus 706: return private;
707: }
708:
1.76 itojun 709: static int
1.96 markus 710: identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
711: u_char *data, u_int datalen)
1.51 markus 712: {
713: Key *private;
714: int idx, ret;
715:
716: idx = authctxt->last_key_hint;
717: if (idx < 0)
718: return -1;
1.80 markus 719:
720: /* private key is stored in external hardware */
1.88 deraadt 721: if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
1.80 markus 722: return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
723:
1.51 markus 724: private = load_identity_file(options.identity_files[idx]);
725: if (private == NULL)
726: return -1;
727: ret = key_sign(private, sigp, lenp, data, datalen);
728: key_free(private);
1.17 markus 729: return ret;
730: }
731:
1.76 itojun 732: static int
1.96 markus 733: agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
734: u_char *data, u_int datalen)
1.17 markus 735: {
1.20 markus 736: return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
1.17 markus 737: }
738:
1.76 itojun 739: static int
1.96 markus 740: key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
741: u_char *data, u_int datalen)
1.51 markus 742: {
1.67 markus 743: return key_sign(key, sigp, lenp, data, datalen);
1.51 markus 744: }
745:
1.76 itojun 746: static int
1.20 markus 747: userauth_pubkey_agent(Authctxt *authctxt)
1.17 markus 748: {
749: static int called = 0;
1.28 markus 750: int ret = 0;
1.17 markus 751: char *comment;
752: Key *k;
753:
754: if (called == 0) {
1.28 markus 755: if (ssh_get_num_identities(authctxt->agent, 2) == 0)
756: debug2("userauth_pubkey_agent: no keys at all");
1.20 markus 757: called = 1;
1.17 markus 758: }
1.28 markus 759: k = ssh_get_next_identity(authctxt->agent, &comment, 2);
1.20 markus 760: if (k == NULL) {
1.28 markus 761: debug2("userauth_pubkey_agent: no more keys");
762: } else {
1.51 markus 763: debug("userauth_pubkey_agent: testing agent key %s", comment);
1.28 markus 764: xfree(comment);
1.51 markus 765: ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
766: if (ret == 0)
767: key_free(k);
1.20 markus 768: }
1.28 markus 769: if (ret == 0)
770: debug2("userauth_pubkey_agent: no message sent");
1.17 markus 771: return ret;
1.1 markus 772: }
773:
1.20 markus 774: int
775: userauth_pubkey(Authctxt *authctxt)
776: {
777: static int idx = 0;
778: int sent = 0;
1.51 markus 779: Key *key;
780: char *filename;
1.20 markus 781:
1.28 markus 782: if (authctxt->agent != NULL) {
783: do {
784: sent = userauth_pubkey_agent(authctxt);
1.87 deraadt 785: } while (!sent && authctxt->agent->howmany > 0);
1.28 markus 786: }
787: while (!sent && idx < options.num_identity_files) {
1.51 markus 788: key = options.identity_keys[idx];
789: filename = options.identity_files[idx];
790: if (key == NULL) {
791: debug("try privkey: %s", filename);
792: key = load_identity_file(filename);
793: if (key != NULL) {
794: sent = sign_and_send_pubkey(authctxt, key,
795: key_sign_cb);
796: key_free(key);
797: }
798: } else if (key->type != KEY_RSA1) {
799: debug("try pubkey: %s", filename);
800: sent = send_pubkey_test(authctxt, key,
801: identity_sign_cb, idx);
802: }
1.28 markus 803: idx++;
804: }
1.20 markus 805: return sent;
806: }
807:
1.23 markus 808: /*
809: * Send userauth request message specifying keyboard-interactive method.
810: */
811: int
812: userauth_kbdint(Authctxt *authctxt)
813: {
814: static int attempt = 0;
815:
816: if (attempt++ >= options.number_of_password_prompts)
817: return 0;
1.82 markus 818: /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
819: if (attempt > 1 && !authctxt->info_req_seen) {
820: debug3("userauth_kbdint: disable: no info_req_seen");
821: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
822: return 0;
823: }
1.23 markus 824:
825: debug2("userauth_kbdint");
826: packet_start(SSH2_MSG_USERAUTH_REQUEST);
827: packet_put_cstring(authctxt->server_user);
828: packet_put_cstring(authctxt->service);
829: packet_put_cstring(authctxt->method->name);
830: packet_put_cstring(""); /* lang */
831: packet_put_cstring(options.kbd_interactive_devices ?
832: options.kbd_interactive_devices : "");
833: packet_send();
834:
835: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
836: return 1;
837: }
838:
839: /*
1.46 markus 840: * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1.23 markus 841: */
842: void
1.92 markus 843: input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1.23 markus 844: {
845: Authctxt *authctxt = ctxt;
1.46 markus 846: char *name, *inst, *lang, *prompt, *response;
1.32 markus 847: u_int num_prompts, i;
1.23 markus 848: int echo = 0;
849:
850: debug2("input_userauth_info_req");
851:
852: if (authctxt == NULL)
853: fatal("input_userauth_info_req: no authentication context");
1.82 markus 854:
855: authctxt->info_req_seen = 1;
1.23 markus 856:
857: name = packet_get_string(NULL);
858: inst = packet_get_string(NULL);
859: lang = packet_get_string(NULL);
860: if (strlen(name) > 0)
1.78 markus 861: log("%s", name);
1.23 markus 862: if (strlen(inst) > 0)
1.78 markus 863: log("%s", inst);
1.46 markus 864: xfree(name);
1.23 markus 865: xfree(inst);
1.46 markus 866: xfree(lang);
1.23 markus 867:
868: num_prompts = packet_get_int();
869: /*
870: * Begin to build info response packet based on prompts requested.
871: * We commit to providing the correct number of responses, so if
872: * further on we run into a problem that prevents this, we have to
873: * be sure and clean this up and send a correct error response.
874: */
875: packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
876: packet_put_int(num_prompts);
877:
1.73 markus 878: debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1.23 markus 879: for (i = 0; i < num_prompts; i++) {
880: prompt = packet_get_string(NULL);
881: echo = packet_get_char();
882:
1.77 markus 883: response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1.23 markus 884:
1.49 markus 885: packet_put_cstring(response);
1.23 markus 886: memset(response, 0, strlen(response));
887: xfree(response);
888: xfree(prompt);
889: }
1.90 markus 890: packet_check_eom(); /* done with parsing incoming message. */
1.23 markus 891:
1.85 markus 892: packet_add_padding(64);
1.23 markus 893: packet_send();
1.68 markus 894: }
895:
896: /*
897: * this will be move to an external program (ssh-keysign) ASAP. ssh-keysign
898: * will be setuid-root and the sbit can be removed from /usr/bin/ssh.
899: */
900: int
901: userauth_hostbased(Authctxt *authctxt)
902: {
903: Key *private = NULL;
904: Buffer b;
905: u_char *signature, *blob;
906: char *chost, *pkalg, *p;
1.72 markus 907: const char *service;
1.68 markus 908: u_int blen, slen;
1.71 markus 909: int ok, i, len, found = 0;
1.68 markus 910:
911: /* check for a useful key */
912: for (i = 0; i < authctxt->nkeys; i++) {
913: private = authctxt->keys[i];
914: if (private && private->type != KEY_RSA1) {
915: found = 1;
916: /* we take and free the key */
917: authctxt->keys[i] = NULL;
918: break;
919: }
920: }
921: if (!found) {
1.84 markus 922: debug("userauth_hostbased: no more client hostkeys");
1.68 markus 923: return 0;
924: }
925: if (key_to_blob(private, &blob, &blen) == 0) {
926: key_free(private);
927: return 0;
928: }
1.84 markus 929: /* figure out a name for the client host */
930: p = get_local_name(packet_get_connection_in());
931: if (p == NULL) {
932: error("userauth_hostbased: cannot get local ipaddr/name");
933: key_free(private);
934: return 0;
935: }
936: len = strlen(p) + 2;
937: chost = xmalloc(len);
938: strlcpy(chost, p, len);
939: strlcat(chost, ".", len);
940: debug2("userauth_hostbased: chost %s", chost);
941:
1.72 markus 942: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
943: authctxt->service;
1.68 markus 944: pkalg = xstrdup(key_ssh_name(private));
945: buffer_init(&b);
946: /* construct data */
1.72 markus 947: buffer_put_string(&b, session_id2, session_id2_len);
1.68 markus 948: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
949: buffer_put_cstring(&b, authctxt->server_user);
1.72 markus 950: buffer_put_cstring(&b, service);
1.68 markus 951: buffer_put_cstring(&b, authctxt->method->name);
952: buffer_put_cstring(&b, pkalg);
953: buffer_put_string(&b, blob, blen);
954: buffer_put_cstring(&b, chost);
955: buffer_put_cstring(&b, authctxt->local_user);
956: #ifdef DEBUG_PK
957: buffer_dump(&b);
958: #endif
959: ok = key_sign(private, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
960: key_free(private);
961: buffer_free(&b);
962: if (ok != 0) {
963: error("key_sign failed");
964: xfree(chost);
965: xfree(pkalg);
966: return 0;
967: }
968: packet_start(SSH2_MSG_USERAUTH_REQUEST);
969: packet_put_cstring(authctxt->server_user);
970: packet_put_cstring(authctxt->service);
971: packet_put_cstring(authctxt->method->name);
972: packet_put_cstring(pkalg);
973: packet_put_string(blob, blen);
974: packet_put_cstring(chost);
975: packet_put_cstring(authctxt->local_user);
976: packet_put_string(signature, slen);
977: memset(signature, 's', slen);
978: xfree(signature);
979: xfree(chost);
980: xfree(pkalg);
981:
982: packet_send();
983: return 1;
1.23 markus 984: }
1.20 markus 985:
986: /* find auth method */
987:
988: /*
989: * given auth method name, if configurable options permit this method fill
990: * in auth_ident field and return true, otherwise return false.
991: */
1.76 itojun 992: static int
1.20 markus 993: authmethod_is_enabled(Authmethod *method)
994: {
995: if (method == NULL)
996: return 0;
997: /* return false if options indicate this method is disabled */
998: if (method->enabled == NULL || *method->enabled == 0)
999: return 0;
1000: /* return false if batch mode is enabled but method needs interactive mode */
1001: if (method->batch_flag != NULL && *method->batch_flag != 0)
1002: return 0;
1003: return 1;
1004: }
1005:
1.76 itojun 1006: static Authmethod *
1.20 markus 1007: authmethod_lookup(const char *name)
1.1 markus 1008: {
1.20 markus 1009: Authmethod *method = NULL;
1010: if (name != NULL)
1011: for (method = authmethods; method->name != NULL; method++)
1012: if (strcmp(name, method->name) == 0)
1013: return method;
1014: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1015: return NULL;
1016: }
1.1 markus 1017:
1.53 markus 1018: /* XXX internal state */
1019: static Authmethod *current = NULL;
1020: static char *supported = NULL;
1021: static char *preferred = NULL;
1.20 markus 1022: /*
1023: * Given the authentication method list sent by the server, return the
1024: * next method we should try. If the server initially sends a nil list,
1.67 markus 1025: * use a built-in default list.
1.41 stevesk 1026: */
1.76 itojun 1027: static Authmethod *
1.20 markus 1028: authmethod_get(char *authlist)
1029: {
1.53 markus 1030:
1031: char *name = NULL;
1.97 markus 1032: u_int next;
1.41 stevesk 1033:
1.20 markus 1034: /* Use a suitable default if we're passed a nil list. */
1035: if (authlist == NULL || strlen(authlist) == 0)
1.53 markus 1036: authlist = options.preferred_authentications;
1.20 markus 1037:
1.53 markus 1038: if (supported == NULL || strcmp(authlist, supported) != 0) {
1039: debug3("start over, passed a different list %s", authlist);
1040: if (supported != NULL)
1041: xfree(supported);
1042: supported = xstrdup(authlist);
1043: preferred = options.preferred_authentications;
1044: debug3("preferred %s", preferred);
1045: current = NULL;
1046: } else if (current != NULL && authmethod_is_enabled(current))
1047: return current;
1.20 markus 1048:
1.53 markus 1049: for (;;) {
1050: if ((name = match_list(preferred, supported, &next)) == NULL) {
1051: debug("no more auth methods to try");
1052: current = NULL;
1053: return NULL;
1054: }
1055: preferred += next;
1.23 markus 1056: debug3("authmethod_lookup %s", name);
1.53 markus 1057: debug3("remaining preferred: %s", preferred);
1058: if ((current = authmethod_lookup(name)) != NULL &&
1059: authmethod_is_enabled(current)) {
1.23 markus 1060: debug3("authmethod_is_enabled %s", name);
1.53 markus 1061: debug("next auth method to try is %s", name);
1062: return current;
1.23 markus 1063: }
1.1 markus 1064: }
1.53 markus 1065: }
1.1 markus 1066:
1.79 stevesk 1067: static char *
1.53 markus 1068: authmethods_get(void)
1069: {
1070: Authmethod *method = NULL;
1.93 markus 1071: Buffer b;
1072: char *list;
1.27 provos 1073:
1.93 markus 1074: buffer_init(&b);
1.53 markus 1075: for (method = authmethods; method->name != NULL; method++) {
1076: if (authmethod_is_enabled(method)) {
1.93 markus 1077: if (buffer_len(&b) > 0)
1078: buffer_append(&b, ",", 1);
1079: buffer_append(&b, method->name, strlen(method->name));
1.53 markus 1080: }
1081: }
1.93 markus 1082: buffer_append(&b, "\0", 1);
1083: list = xstrdup(buffer_ptr(&b));
1084: buffer_free(&b);
1085: return list;
1.1 markus 1086: }
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