Annotation of src/usr.bin/ssh/sshconnect2.c, Revision 1.27.2.1
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"
1.27.2.1! jason 26: RCSID("$OpenBSD: sshconnect2.c,v 1.48 2001/02/15 23:19:59 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"
1.27.2.1! jason 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"
1.27.2.1! jason 42: #include "cipher.h"
1.1 markus 43: #include "kex.h"
44: #include "myproposal.h"
45: #include "key.h"
46: #include "sshconnect.h"
47: #include "authfile.h"
1.23 markus 48: #include "cli.h"
1.20 markus 49: #include "dispatch.h"
1.17 markus 50: #include "authfd.h"
1.27.2.1! jason 51: #include "log.h"
! 52: #include "readconf.h"
! 53: #include "readpass.h"
1.1 markus 54:
1.22 provos 55: void ssh_dh1_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *);
56: void ssh_dhgex_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *);
57:
1.1 markus 58: /* import */
59: extern char *client_version_string;
60: extern char *server_version_string;
61: extern Options options;
62:
63: /*
64: * SSH2 key exchange
65: */
66:
1.27.2.1! jason 67: u_char *session_id2 = NULL;
1.1 markus 68: int session_id2_len = 0;
69:
70: void
1.22 provos 71: ssh_kex2(char *host, struct sockaddr *hostaddr)
72: {
73: int i, plen;
74: Kex *kex;
75: Buffer *client_kexinit, *server_kexinit;
76: char *sprop[PROPOSAL_MAX];
77:
1.27.2.1! jason 78: if (options.ciphers == (char *)-1) {
! 79: log("No valid ciphers for protocol version 2 given, using defaults.");
! 80: options.ciphers = NULL;
1.24 markus 81: }
1.22 provos 82: if (options.ciphers != NULL) {
83: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
84: myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
85: }
86: if (options.compression) {
1.27.2.1! jason 87: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.22 provos 88: myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
89: } else {
1.27.2.1! jason 90: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.22 provos 91: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
92: }
1.27.2.1! jason 93: if (options.macs != NULL) {
! 94: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
! 95: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
! 96: }
1.22 provos 97:
98: /* buffers with raw kexinit messages */
99: server_kexinit = xmalloc(sizeof(*server_kexinit));
100: buffer_init(server_kexinit);
101: client_kexinit = kex_init(myproposal);
102:
103: /* algorithm negotiation */
104: kex_exchange_kexinit(client_kexinit, server_kexinit, sprop);
105: kex = kex_choose_conf(myproposal, sprop, 0);
106: for (i = 0; i < PROPOSAL_MAX; i++)
107: xfree(sprop[i]);
108:
109: /* server authentication and session key agreement */
110: switch(kex->kex_type) {
111: case DH_GRP1_SHA1:
112: ssh_dh1_client(kex, host, hostaddr,
113: client_kexinit, server_kexinit);
114: break;
115: case DH_GEX_SHA1:
116: ssh_dhgex_client(kex, host, hostaddr, client_kexinit,
117: server_kexinit);
118: break;
119: default:
120: fatal("Unsupported key exchange %d", kex->kex_type);
121: }
122:
123: buffer_free(client_kexinit);
124: buffer_free(server_kexinit);
125: xfree(client_kexinit);
126: xfree(server_kexinit);
127:
128: debug("Wait SSH2_MSG_NEWKEYS.");
129: packet_read_expect(&plen, SSH2_MSG_NEWKEYS);
130: packet_done();
131: debug("GOT SSH2_MSG_NEWKEYS.");
132:
133: debug("send SSH2_MSG_NEWKEYS.");
134: packet_start(SSH2_MSG_NEWKEYS);
135: packet_send();
136: packet_write_wait();
137: debug("done: send SSH2_MSG_NEWKEYS.");
138:
139: #ifdef DEBUG_KEXDH
140: /* send 1st encrypted/maced/compressed message */
141: packet_start(SSH2_MSG_IGNORE);
142: packet_put_cstring("markus");
143: packet_send();
144: packet_write_wait();
145: #endif
146: debug("done: KEX2.");
147: }
148:
149: /* diffie-hellman-group1-sha1 */
150:
151: void
1.27.2.1! jason 152: ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr,
1.22 provos 153: Buffer *client_kexinit, Buffer *server_kexinit)
1.1 markus 154: {
1.19 markus 155: #ifdef DEBUG_KEXDH
156: int i;
157: #endif
1.11 markus 158: int plen, dlen;
1.27.2.1! jason 159: u_int klen, kout;
1.1 markus 160: char *signature = NULL;
1.27.2.1! jason 161: u_int slen;
1.1 markus 162: char *server_host_key_blob = NULL;
163: Key *server_host_key;
1.27.2.1! jason 164: u_int sbloblen;
1.1 markus 165: DH *dh;
166: BIGNUM *dh_server_pub = 0;
167: BIGNUM *shared_secret = 0;
1.27.2.1! jason 168: u_char *kbuf;
! 169: u_char *hash;
1.1 markus 170:
171: debug("Sending SSH2_MSG_KEXDH_INIT.");
172: /* generate and send 'e', client DH public key */
173: dh = dh_new_group1();
1.27.2.1! jason 174: dh_gen_key(dh);
1.1 markus 175: packet_start(SSH2_MSG_KEXDH_INIT);
176: packet_put_bignum2(dh->pub_key);
177: packet_send();
178: packet_write_wait();
179:
180: #ifdef DEBUG_KEXDH
181: fprintf(stderr, "\np= ");
1.19 markus 182: BN_print_fp(stderr, dh->p);
1.1 markus 183: fprintf(stderr, "\ng= ");
1.19 markus 184: BN_print_fp(stderr, dh->g);
1.1 markus 185: fprintf(stderr, "\npub= ");
1.19 markus 186: BN_print_fp(stderr, dh->pub_key);
1.1 markus 187: fprintf(stderr, "\n");
188: DHparams_print_fp(stderr, dh);
189: #endif
190:
191: debug("Wait SSH2_MSG_KEXDH_REPLY.");
192:
1.11 markus 193: packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY);
1.1 markus 194:
195: debug("Got SSH2_MSG_KEXDH_REPLY.");
196:
197: /* key, cert */
198: server_host_key_blob = packet_get_string(&sbloblen);
1.27.2.1! jason 199: server_host_key = key_from_blob(server_host_key_blob, sbloblen);
1.1 markus 200: if (server_host_key == NULL)
201: fatal("cannot decode server_host_key_blob");
202:
203: check_host_key(host, hostaddr, server_host_key,
1.22 provos 204: options.user_hostfile2, options.system_hostfile2);
1.1 markus 205:
206: /* DH paramter f, server public DH key */
207: dh_server_pub = BN_new();
208: if (dh_server_pub == NULL)
209: fatal("dh_server_pub == NULL");
210: packet_get_bignum2(dh_server_pub, &dlen);
211:
212: #ifdef DEBUG_KEXDH
213: fprintf(stderr, "\ndh_server_pub= ");
1.19 markus 214: BN_print_fp(stderr, dh_server_pub);
1.1 markus 215: fprintf(stderr, "\n");
216: debug("bits %d", BN_num_bits(dh_server_pub));
217: #endif
218:
219: /* signed H */
220: signature = packet_get_string(&slen);
221: packet_done();
222:
223: if (!dh_pub_is_valid(dh, dh_server_pub))
224: packet_disconnect("bad server public DH value");
225:
226: klen = DH_size(dh);
227: kbuf = xmalloc(klen);
228: kout = DH_compute_key(kbuf, dh_server_pub, dh);
229: #ifdef DEBUG_KEXDH
230: debug("shared secret: len %d/%d", klen, kout);
231: fprintf(stderr, "shared secret == ");
232: for (i = 0; i< kout; i++)
233: fprintf(stderr, "%02x", (kbuf[i])&0xff);
234: fprintf(stderr, "\n");
235: #endif
236: shared_secret = BN_new();
237:
238: BN_bin2bn(kbuf, kout, shared_secret);
239: memset(kbuf, 0, klen);
240: xfree(kbuf);
241:
242: /* calc and verify H */
243: hash = kex_hash(
244: client_version_string,
245: server_version_string,
246: buffer_ptr(client_kexinit), buffer_len(client_kexinit),
247: buffer_ptr(server_kexinit), buffer_len(server_kexinit),
248: server_host_key_blob, sbloblen,
249: dh->pub_key,
250: dh_server_pub,
251: shared_secret
252: );
1.3 markus 253: xfree(server_host_key_blob);
1.11 markus 254: DH_free(dh);
1.27.2.1! jason 255: BN_free(dh_server_pub);
1.1 markus 256: #ifdef DEBUG_KEXDH
257: fprintf(stderr, "hash == ");
258: for (i = 0; i< 20; i++)
259: fprintf(stderr, "%02x", (hash[i])&0xff);
260: fprintf(stderr, "\n");
261: #endif
1.27.2.1! jason 262: if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
! 263: fatal("key_verify failed for server_host_key");
1.1 markus 264: key_free(server_host_key);
1.27.2.1! jason 265: xfree(signature);
1.1 markus 266:
267: kex_derive_keys(kex, hash, shared_secret);
1.27.2.1! jason 268: BN_clear_free(shared_secret);
1.1 markus 269: packet_set_kex(kex);
270:
271: /* save session id */
272: session_id2_len = 20;
273: session_id2 = xmalloc(session_id2_len);
274: memcpy(session_id2, hash, session_id2_len);
1.11 markus 275: }
276:
1.22 provos 277: /* diffie-hellman-group-exchange-sha1 */
278:
279: /*
280: * Estimates the group order for a Diffie-Hellman group that has an
281: * attack complexity approximately the same as O(2**bits). Estimate
282: * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3)))
283: */
284:
285: int
286: dh_estimate(int bits)
287: {
1.27.2.1! jason 288:
1.22 provos 289: if (bits < 64)
290: return (512); /* O(2**63) */
291: if (bits < 128)
292: return (1024); /* O(2**86) */
293: if (bits < 192)
294: return (2048); /* O(2**116) */
295: return (4096); /* O(2**156) */
296: }
297:
1.11 markus 298: void
1.22 provos 299: ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr,
300: Buffer *client_kexinit, Buffer *server_kexinit)
1.11 markus 301: {
1.22 provos 302: #ifdef DEBUG_KEXDH
303: int i;
304: #endif
305: int plen, dlen;
1.27.2.1! jason 306: u_int klen, kout;
1.22 provos 307: char *signature = NULL;
1.27.2.1! jason 308: u_int slen, nbits;
1.22 provos 309: char *server_host_key_blob = NULL;
310: Key *server_host_key;
1.27.2.1! jason 311: u_int sbloblen;
1.22 provos 312: DH *dh;
313: BIGNUM *dh_server_pub = 0;
314: BIGNUM *shared_secret = 0;
315: BIGNUM *p = 0, *g = 0;
1.27.2.1! jason 316: u_char *kbuf;
! 317: u_char *hash;
1.22 provos 318:
1.24 markus 319: nbits = dh_estimate(kex->enc[MODE_OUT].cipher->key_len * 8);
1.22 provos 320:
321: debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST.");
322: packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST);
323: packet_put_int(nbits);
324: packet_send();
325: packet_write_wait();
1.11 markus 326:
1.22 provos 327: #ifdef DEBUG_KEXDH
328: fprintf(stderr, "\nnbits = %d", nbits);
329: #endif
1.11 markus 330:
1.22 provos 331: debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP.");
1.11 markus 332:
1.22 provos 333: packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP);
1.11 markus 334:
1.22 provos 335: debug("Got SSH2_MSG_KEX_DH_GEX_GROUP.");
1.11 markus 336:
1.22 provos 337: if ((p = BN_new()) == NULL)
338: fatal("BN_new");
339: packet_get_bignum2(p, &dlen);
340: if ((g = BN_new()) == NULL)
341: fatal("BN_new");
342: packet_get_bignum2(g, &dlen);
1.27.2.1! jason 343: dh = dh_new_group(g, p);
! 344:
! 345: dh_gen_key(dh);
1.1 markus 346:
1.22 provos 347: #ifdef DEBUG_KEXDH
348: fprintf(stderr, "\np= ");
349: BN_print_fp(stderr, dh->p);
350: fprintf(stderr, "\ng= ");
351: BN_print_fp(stderr, dh->g);
352: fprintf(stderr, "\npub= ");
353: BN_print_fp(stderr, dh->pub_key);
354: fprintf(stderr, "\n");
355: DHparams_print_fp(stderr, dh);
356: #endif
1.1 markus 357:
1.22 provos 358: debug("Sending SSH2_MSG_KEX_DH_GEX_INIT.");
359: /* generate and send 'e', client DH public key */
360: packet_start(SSH2_MSG_KEX_DH_GEX_INIT);
361: packet_put_bignum2(dh->pub_key);
1.1 markus 362: packet_send();
363: packet_write_wait();
364:
1.22 provos 365: debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY.");
366:
367: packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY);
368:
369: debug("Got SSH2_MSG_KEXDH_REPLY.");
370:
371: /* key, cert */
372: server_host_key_blob = packet_get_string(&sbloblen);
1.27.2.1! jason 373: server_host_key = key_from_blob(server_host_key_blob, sbloblen);
1.22 provos 374: if (server_host_key == NULL)
375: fatal("cannot decode server_host_key_blob");
376:
377: check_host_key(host, hostaddr, server_host_key,
378: options.user_hostfile2, options.system_hostfile2);
379:
380: /* DH paramter f, server public DH key */
381: dh_server_pub = BN_new();
382: if (dh_server_pub == NULL)
383: fatal("dh_server_pub == NULL");
384: packet_get_bignum2(dh_server_pub, &dlen);
385:
386: #ifdef DEBUG_KEXDH
387: fprintf(stderr, "\ndh_server_pub= ");
388: BN_print_fp(stderr, dh_server_pub);
389: fprintf(stderr, "\n");
390: debug("bits %d", BN_num_bits(dh_server_pub));
391: #endif
392:
393: /* signed H */
394: signature = packet_get_string(&slen);
395: packet_done();
396:
397: if (!dh_pub_is_valid(dh, dh_server_pub))
398: packet_disconnect("bad server public DH value");
399:
400: klen = DH_size(dh);
401: kbuf = xmalloc(klen);
402: kout = DH_compute_key(kbuf, dh_server_pub, dh);
403: #ifdef DEBUG_KEXDH
404: debug("shared secret: len %d/%d", klen, kout);
405: fprintf(stderr, "shared secret == ");
406: for (i = 0; i< kout; i++)
407: fprintf(stderr, "%02x", (kbuf[i])&0xff);
408: fprintf(stderr, "\n");
409: #endif
410: shared_secret = BN_new();
411:
412: BN_bin2bn(kbuf, kout, shared_secret);
413: memset(kbuf, 0, klen);
414: xfree(kbuf);
415:
416: /* calc and verify H */
417: hash = kex_hash_gex(
418: client_version_string,
419: server_version_string,
420: buffer_ptr(client_kexinit), buffer_len(client_kexinit),
421: buffer_ptr(server_kexinit), buffer_len(server_kexinit),
422: server_host_key_blob, sbloblen,
1.27.2.1! jason 423: nbits, dh->p, dh->g,
1.22 provos 424: dh->pub_key,
425: dh_server_pub,
426: shared_secret
427: );
428: xfree(server_host_key_blob);
429: DH_free(dh);
1.27.2.1! jason 430: BN_free(dh_server_pub);
1.1 markus 431: #ifdef DEBUG_KEXDH
1.22 provos 432: fprintf(stderr, "hash == ");
433: for (i = 0; i< 20; i++)
434: fprintf(stderr, "%02x", (hash[i])&0xff);
435: fprintf(stderr, "\n");
1.1 markus 436: #endif
1.27.2.1! jason 437: if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
! 438: fatal("key_verify failed for server_host_key");
1.22 provos 439: key_free(server_host_key);
1.27.2.1! jason 440: xfree(signature);
1.22 provos 441:
442: kex_derive_keys(kex, hash, shared_secret);
1.27.2.1! jason 443: BN_clear_free(shared_secret);
1.22 provos 444: packet_set_kex(kex);
445:
446: /* save session id */
447: session_id2_len = 20;
448: session_id2 = xmalloc(session_id2_len);
449: memcpy(session_id2, hash, session_id2_len);
1.1 markus 450: }
1.11 markus 451:
1.1 markus 452: /*
453: * Authenticate user
454: */
1.20 markus 455:
456: typedef struct Authctxt Authctxt;
457: typedef struct Authmethod Authmethod;
458:
459: typedef int sign_cb_fn(
460: Authctxt *authctxt, Key *key,
1.27.2.1! jason 461: u_char **sigp, int *lenp, u_char *data, int datalen);
1.20 markus 462:
463: struct Authctxt {
464: const char *server_user;
465: const char *host;
466: const char *service;
467: AuthenticationConnection *agent;
1.23 markus 468: Authmethod *method;
1.20 markus 469: int success;
470: };
471: struct Authmethod {
472: char *name; /* string to compare against server's list */
473: int (*userauth)(Authctxt *authctxt);
474: int *enabled; /* flag in option struct that enables method */
475: int *batch_flag; /* flag in option struct that disables method */
476: };
477:
478: void input_userauth_success(int type, int plen, void *ctxt);
479: void input_userauth_failure(int type, int plen, void *ctxt);
1.27.2.1! jason 480: void input_userauth_banner(int type, int plen, void *ctxt);
1.20 markus 481: void input_userauth_error(int type, int plen, void *ctxt);
1.23 markus 482: void input_userauth_info_req(int type, int plen, void *ctxt);
483:
484: int userauth_none(Authctxt *authctxt);
1.20 markus 485: int userauth_pubkey(Authctxt *authctxt);
486: int userauth_passwd(Authctxt *authctxt);
1.23 markus 487: int userauth_kbdint(Authctxt *authctxt);
1.20 markus 488:
1.27.2.1! jason 489: void authmethod_clear(void);
1.23 markus 490: Authmethod *authmethod_get(char *authlist);
491: Authmethod *authmethod_lookup(const char *name);
1.20 markus 492:
493: Authmethod authmethods[] = {
494: {"publickey",
495: userauth_pubkey,
1.27.2.1! jason 496: &options.pubkey_authentication,
1.20 markus 497: NULL},
498: {"password",
499: userauth_passwd,
500: &options.password_authentication,
501: &options.batch_mode},
1.23 markus 502: {"keyboard-interactive",
503: userauth_kbdint,
504: &options.kbd_interactive_authentication,
505: &options.batch_mode},
506: {"none",
507: userauth_none,
508: NULL,
509: NULL},
1.20 markus 510: {NULL, NULL, NULL, NULL}
511: };
512:
513: void
514: ssh_userauth2(const char *server_user, char *host)
515: {
516: Authctxt authctxt;
517: int type;
518: int plen;
519:
1.27.2.1! jason 520: if (options.challenge_reponse_authentication)
! 521: options.kbd_interactive_authentication = 1;
! 522:
1.20 markus 523: debug("send SSH2_MSG_SERVICE_REQUEST");
524: packet_start(SSH2_MSG_SERVICE_REQUEST);
525: packet_put_cstring("ssh-userauth");
526: packet_send();
527: packet_write_wait();
528: type = packet_read(&plen);
529: if (type != SSH2_MSG_SERVICE_ACCEPT) {
530: fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
531: }
532: if (packet_remaining() > 0) {
533: char *reply = packet_get_string(&plen);
534: debug("service_accept: %s", reply);
535: xfree(reply);
536: } else {
537: debug("buggy server: service_accept w/o service");
538: }
539: packet_done();
540: debug("got SSH2_MSG_SERVICE_ACCEPT");
541:
542: /* setup authentication context */
543: authctxt.agent = ssh_get_authentication_connection();
544: authctxt.server_user = server_user;
545: authctxt.host = host;
546: authctxt.service = "ssh-connection"; /* service name */
547: authctxt.success = 0;
1.23 markus 548: authctxt.method = authmethod_lookup("none");
549: if (authctxt.method == NULL)
550: fatal("ssh_userauth2: internal error: cannot send userauth none request");
551: authmethod_clear();
1.20 markus 552:
553: /* initial userauth request */
1.23 markus 554: userauth_none(&authctxt);
1.20 markus 555:
556: dispatch_init(&input_userauth_error);
557: dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
558: dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
1.27.2.1! jason 559: dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
1.20 markus 560: dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
561:
562: if (authctxt.agent != NULL)
563: ssh_close_authentication_connection(authctxt.agent);
564:
1.27.2.1! jason 565: debug("ssh-userauth2 successful: method %s", authctxt.method->name);
1.20 markus 566: }
567: void
568: input_userauth_error(int type, int plen, void *ctxt)
569: {
1.27.2.1! jason 570: fatal("input_userauth_error: bad message during authentication: "
! 571: "type %d", type);
! 572: }
! 573: void
! 574: input_userauth_banner(int type, int plen, void *ctxt)
! 575: {
! 576: char *msg, *lang;
! 577: debug3("input_userauth_banner");
! 578: msg = packet_get_string(NULL);
! 579: lang = packet_get_string(NULL);
! 580: fprintf(stderr, "%s", msg);
! 581: xfree(msg);
! 582: xfree(lang);
1.20 markus 583: }
584: void
585: input_userauth_success(int type, int plen, void *ctxt)
586: {
587: Authctxt *authctxt = ctxt;
588: if (authctxt == NULL)
589: fatal("input_userauth_success: no authentication context");
590: authctxt->success = 1; /* break out */
591: }
592: void
593: input_userauth_failure(int type, int plen, void *ctxt)
594: {
595: Authmethod *method = NULL;
596: Authctxt *authctxt = ctxt;
597: char *authlist = NULL;
598: int partial;
599:
600: if (authctxt == NULL)
601: fatal("input_userauth_failure: no authentication context");
602:
1.23 markus 603: authlist = packet_get_string(NULL);
1.20 markus 604: partial = packet_get_char();
605: packet_done();
606:
607: if (partial != 0)
1.27.2.1! jason 608: log("Authenticated with partial success.");
1.20 markus 609: debug("authentications that can continue: %s", authlist);
610:
611: for (;;) {
612: method = authmethod_get(authlist);
613: if (method == NULL)
1.27.2.1! jason 614: fatal("Permission denied (%s).", authlist);
1.23 markus 615: authctxt->method = method;
1.20 markus 616: if (method->userauth(authctxt) != 0) {
1.23 markus 617: debug2("we sent a %s packet, wait for reply", method->name);
1.20 markus 618: break;
619: } else {
620: debug2("we did not send a packet, disable method");
621: method->enabled = NULL;
622: }
1.27.2.1! jason 623: }
1.20 markus 624: xfree(authlist);
625: }
626:
1.1 markus 627: int
1.23 markus 628: userauth_none(Authctxt *authctxt)
629: {
630: /* initial userauth request */
631: packet_start(SSH2_MSG_USERAUTH_REQUEST);
632: packet_put_cstring(authctxt->server_user);
633: packet_put_cstring(authctxt->service);
634: packet_put_cstring(authctxt->method->name);
635: packet_send();
636: packet_write_wait();
637: return 1;
638: }
639:
640: int
1.20 markus 641: userauth_passwd(Authctxt *authctxt)
1.1 markus 642: {
1.6 markus 643: static int attempt = 0;
1.1 markus 644: char prompt[80];
645: char *password;
1.6 markus 646:
1.13 todd 647: if (attempt++ >= options.number_of_password_prompts)
1.6 markus 648: return 0;
1.13 todd 649:
650: if(attempt != 1)
651: error("Permission denied, please try again.");
1.1 markus 652:
1.27.2.1! jason 653: snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1.20 markus 654: authctxt->server_user, authctxt->host);
1.1 markus 655: password = read_passphrase(prompt, 0);
656: packet_start(SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 657: packet_put_cstring(authctxt->server_user);
658: packet_put_cstring(authctxt->service);
1.23 markus 659: packet_put_cstring(authctxt->method->name);
1.1 markus 660: packet_put_char(0);
1.27.2.1! jason 661: ssh_put_password(password);
1.1 markus 662: memset(password, 0, strlen(password));
663: xfree(password);
664: packet_send();
665: packet_write_wait();
666: return 1;
667: }
668:
1.17 markus 669: int
1.20 markus 670: sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
1.1 markus 671: {
672: Buffer b;
1.27.2.1! jason 673: u_char *blob, *signature;
1.1 markus 674: int bloblen, slen;
1.14 markus 675: int skip = 0;
1.17 markus 676: int ret = -1;
1.23 markus 677: int have_sig = 1;
1.1 markus 678:
1.27.2.1! jason 679: debug3("sign_and_send_pubkey");
! 680: if (key_to_blob(k, &blob, &bloblen) == 0) {
! 681: /* we cannot handle this key */
! 682: debug3("sign_and_send_pubkey: cannot handle key");
! 683: return 0;
! 684: }
1.1 markus 685: /* data to be signed */
686: buffer_init(&b);
1.26 markus 687: if (datafellows & SSH_OLD_SESSIONID) {
688: buffer_append(&b, session_id2, session_id2_len);
1.27.2.1! jason 689: skip = session_id2_len;
1.26 markus 690: } else {
1.14 markus 691: buffer_put_string(&b, session_id2, session_id2_len);
692: skip = buffer_len(&b);
693: }
1.1 markus 694: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 695: buffer_put_cstring(&b, authctxt->server_user);
1.10 markus 696: buffer_put_cstring(&b,
1.27.2.1! jason 697: datafellows & SSH_BUG_PKSERVICE ?
1.10 markus 698: "ssh-userauth" :
1.20 markus 699: authctxt->service);
1.27.2.1! jason 700: if (datafellows & SSH_BUG_PKAUTH) {
! 701: buffer_put_char(&b, have_sig);
! 702: } else {
! 703: buffer_put_cstring(&b, authctxt->method->name);
! 704: buffer_put_char(&b, have_sig);
! 705: buffer_put_cstring(&b, key_ssh_name(k));
! 706: }
1.1 markus 707: buffer_put_string(&b, blob, bloblen);
708:
709: /* generate signature */
1.20 markus 710: ret = (*sign_callback)(authctxt, k, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
1.17 markus 711: if (ret == -1) {
712: xfree(blob);
713: buffer_free(&b);
714: return 0;
715: }
1.27.2.1! jason 716: #ifdef DEBUG_PK
1.1 markus 717: buffer_dump(&b);
718: #endif
1.27.2.1! jason 719: if (datafellows & SSH_BUG_PKSERVICE) {
1.10 markus 720: buffer_clear(&b);
721: buffer_append(&b, session_id2, session_id2_len);
722: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 723: buffer_put_cstring(&b, authctxt->server_user);
724: buffer_put_cstring(&b, authctxt->service);
1.23 markus 725: buffer_put_cstring(&b, authctxt->method->name);
726: buffer_put_char(&b, have_sig);
1.27.2.1! jason 727: if (!(datafellows & SSH_BUG_PKAUTH))
! 728: buffer_put_cstring(&b, key_ssh_name(k));
1.10 markus 729: buffer_put_string(&b, blob, bloblen);
730: }
731: xfree(blob);
1.1 markus 732: /* append signature */
733: buffer_put_string(&b, signature, slen);
734: xfree(signature);
735:
736: /* skip session id and packet type */
1.14 markus 737: if (buffer_len(&b) < skip + 1)
1.20 markus 738: fatal("userauth_pubkey: internal error");
1.14 markus 739: buffer_consume(&b, skip + 1);
1.1 markus 740:
741: /* put remaining data from buffer into packet */
742: packet_start(SSH2_MSG_USERAUTH_REQUEST);
743: packet_put_raw(buffer_ptr(&b), buffer_len(&b));
744: buffer_free(&b);
745:
746: /* send */
747: packet_send();
748: packet_write_wait();
1.17 markus 749:
750: return 1;
1.16 markus 751: }
752:
1.20 markus 753: /* sign callback */
1.27.2.1! jason 754: int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
! 755: u_char *data, int datalen)
1.20 markus 756: {
1.27.2.1! jason 757: return key_sign(key, sigp, lenp, data, datalen);
1.20 markus 758: }
759:
1.16 markus 760: int
1.20 markus 761: userauth_pubkey_identity(Authctxt *authctxt, char *filename)
1.16 markus 762: {
763: Key *k;
1.27.2.1! jason 764: int i, ret, try_next, success = 0;
1.16 markus 765: struct stat st;
1.27.2.1! jason 766: char *passphrase;
! 767: char prompt[300];
1.16 markus 768:
769: if (stat(filename, &st) != 0) {
770: debug("key does not exist: %s", filename);
771: return 0;
772: }
773: debug("try pubkey: %s", filename);
774:
1.27.2.1! jason 775: k = key_new(KEY_UNSPEC);
1.16 markus 776: if (!load_private_key(filename, "", k, NULL)) {
1.27.2.1! jason 777: if (options.batch_mode) {
! 778: key_free(k);
! 779: return 0;
! 780: }
1.16 markus 781: snprintf(prompt, sizeof prompt,
1.27.2.1! jason 782: "Enter passphrase for key '%.100s': ", filename);
1.20 markus 783: for (i = 0; i < options.number_of_password_prompts; i++) {
784: passphrase = read_passphrase(prompt, 0);
785: if (strcmp(passphrase, "") != 0) {
786: success = load_private_key(filename, passphrase, k, NULL);
787: try_next = 0;
788: } else {
789: debug2("no passphrase given, try next key");
790: try_next = 1;
791: }
792: memset(passphrase, 0, strlen(passphrase));
793: xfree(passphrase);
794: if (success || try_next)
795: break;
796: debug2("bad passphrase given, try again...");
797: }
1.16 markus 798: if (!success) {
799: key_free(k);
800: return 0;
801: }
802: }
1.27.2.1! jason 803: ret = sign_and_send_pubkey(authctxt, k, key_sign_cb);
1.17 markus 804: key_free(k);
805: return ret;
806: }
807:
1.20 markus 808: /* sign callback */
1.27.2.1! jason 809: int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
! 810: u_char *data, int datalen)
1.17 markus 811: {
1.20 markus 812: return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
1.17 markus 813: }
814:
815: int
1.20 markus 816: userauth_pubkey_agent(Authctxt *authctxt)
1.17 markus 817: {
818: static int called = 0;
1.27.2.1! jason 819: int ret = 0;
1.17 markus 820: char *comment;
821: Key *k;
822:
823: if (called == 0) {
1.27.2.1! jason 824: if (ssh_get_num_identities(authctxt->agent, 2) == 0)
! 825: debug2("userauth_pubkey_agent: no keys at all");
1.20 markus 826: called = 1;
1.17 markus 827: }
1.27.2.1! jason 828: k = ssh_get_next_identity(authctxt->agent, &comment, 2);
1.20 markus 829: if (k == NULL) {
1.27.2.1! jason 830: debug2("userauth_pubkey_agent: no more keys");
! 831: } else {
! 832: debug("userauth_pubkey_agent: trying agent key %s", comment);
! 833: xfree(comment);
! 834: ret = sign_and_send_pubkey(authctxt, k, agent_sign_cb);
! 835: key_free(k);
1.20 markus 836: }
1.27.2.1! jason 837: if (ret == 0)
! 838: debug2("userauth_pubkey_agent: no message sent");
1.17 markus 839: return ret;
1.1 markus 840: }
841:
1.20 markus 842: int
843: userauth_pubkey(Authctxt *authctxt)
844: {
845: static int idx = 0;
846: int sent = 0;
847:
1.27.2.1! jason 848: if (authctxt->agent != NULL) {
! 849: do {
! 850: sent = userauth_pubkey_agent(authctxt);
! 851: } while(!sent && authctxt->agent->howmany > 0);
! 852: }
! 853: while (!sent && idx < options.num_identity_files) {
! 854: if (options.identity_files_type[idx] != KEY_RSA1)
! 855: sent = userauth_pubkey_identity(authctxt,
! 856: options.identity_files[idx]);
! 857: idx++;
! 858: }
1.20 markus 859: return sent;
860: }
861:
1.23 markus 862: /*
863: * Send userauth request message specifying keyboard-interactive method.
864: */
865: int
866: userauth_kbdint(Authctxt *authctxt)
867: {
868: static int attempt = 0;
869:
870: if (attempt++ >= options.number_of_password_prompts)
871: return 0;
872:
873: debug2("userauth_kbdint");
874: packet_start(SSH2_MSG_USERAUTH_REQUEST);
875: packet_put_cstring(authctxt->server_user);
876: packet_put_cstring(authctxt->service);
877: packet_put_cstring(authctxt->method->name);
878: packet_put_cstring(""); /* lang */
879: packet_put_cstring(options.kbd_interactive_devices ?
880: options.kbd_interactive_devices : "");
881: packet_send();
882: packet_write_wait();
883:
884: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
885: return 1;
886: }
887:
888: /*
1.27.2.1! jason 889: * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1.23 markus 890: */
891: void
892: input_userauth_info_req(int type, int plen, void *ctxt)
893: {
894: Authctxt *authctxt = ctxt;
1.27.2.1! jason 895: char *name, *inst, *lang, *prompt, *response;
! 896: u_int num_prompts, i;
1.23 markus 897: int echo = 0;
898:
899: debug2("input_userauth_info_req");
900:
901: if (authctxt == NULL)
902: fatal("input_userauth_info_req: no authentication context");
903:
904: name = packet_get_string(NULL);
905: inst = packet_get_string(NULL);
906: lang = packet_get_string(NULL);
907: if (strlen(name) > 0)
908: cli_mesg(name);
909: if (strlen(inst) > 0)
910: cli_mesg(inst);
1.27.2.1! jason 911: xfree(name);
1.23 markus 912: xfree(inst);
1.27.2.1! jason 913: xfree(lang);
1.23 markus 914:
915: num_prompts = packet_get_int();
916: /*
917: * Begin to build info response packet based on prompts requested.
918: * We commit to providing the correct number of responses, so if
919: * further on we run into a problem that prevents this, we have to
920: * be sure and clean this up and send a correct error response.
921: */
922: packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
923: packet_put_int(num_prompts);
924:
925: for (i = 0; i < num_prompts; i++) {
926: prompt = packet_get_string(NULL);
927: echo = packet_get_char();
928:
929: response = cli_prompt(prompt, echo);
930:
1.27.2.1! jason 931: ssh_put_password(response);
1.23 markus 932: memset(response, 0, strlen(response));
933: xfree(response);
934: xfree(prompt);
935: }
936: packet_done(); /* done with parsing incoming message. */
937:
938: packet_send();
939: packet_write_wait();
940: }
1.20 markus 941:
942: /* find auth method */
943:
944: #define DELIM ","
945:
946: static char *def_authlist = "publickey,password";
947: static char *authlist_current = NULL; /* clean copy used for comparison */
948: static char *authname_current = NULL; /* last used auth method */
949: static char *authlist_working = NULL; /* copy that gets modified by strtok_r() */
950: static char *authlist_state = NULL; /* state variable for strtok_r() */
951:
952: /*
953: * Before starting to use a new authentication method list sent by the
954: * server, reset internal variables. This should also be called when
955: * finished processing server list to free resources.
956: */
1.1 markus 957: void
1.27.2.1! jason 958: authmethod_clear(void)
1.20 markus 959: {
960: if (authlist_current != NULL) {
961: xfree(authlist_current);
962: authlist_current = NULL;
963: }
964: if (authlist_working != NULL) {
965: xfree(authlist_working);
966: authlist_working = NULL;
967: }
968: if (authname_current != NULL) {
969: xfree(authname_current);
1.27.2.1! jason 970: authname_current = NULL;
1.20 markus 971: }
972: if (authlist_state != NULL)
973: authlist_state = NULL;
974: return;
975: }
976:
977: /*
978: * given auth method name, if configurable options permit this method fill
979: * in auth_ident field and return true, otherwise return false.
980: */
981: int
982: authmethod_is_enabled(Authmethod *method)
983: {
984: if (method == NULL)
985: return 0;
986: /* return false if options indicate this method is disabled */
987: if (method->enabled == NULL || *method->enabled == 0)
988: return 0;
989: /* return false if batch mode is enabled but method needs interactive mode */
990: if (method->batch_flag != NULL && *method->batch_flag != 0)
991: return 0;
992: return 1;
993: }
994:
995: Authmethod *
996: authmethod_lookup(const char *name)
1.1 markus 997: {
1.20 markus 998: Authmethod *method = NULL;
999: if (name != NULL)
1000: for (method = authmethods; method->name != NULL; method++)
1001: if (strcmp(name, method->name) == 0)
1002: return method;
1003: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1004: return NULL;
1005: }
1.1 markus 1006:
1.20 markus 1007: /*
1008: * Given the authentication method list sent by the server, return the
1009: * next method we should try. If the server initially sends a nil list,
1010: * use a built-in default list. If the server sends a nil list after
1011: * previously sending a valid list, continue using the list originally
1012: * sent.
1.27.2.1! jason 1013: */
1.1 markus 1014:
1.20 markus 1015: Authmethod *
1016: authmethod_get(char *authlist)
1017: {
1.27 provos 1018: char *name = NULL, *authname_old;
1.20 markus 1019: Authmethod *method = NULL;
1.27.2.1! jason 1020:
1.20 markus 1021: /* Use a suitable default if we're passed a nil list. */
1022: if (authlist == NULL || strlen(authlist) == 0)
1023: authlist = def_authlist;
1024:
1025: if (authlist_current == NULL || strcmp(authlist, authlist_current) != 0) {
1026: /* start over if passed a different list */
1.23 markus 1027: debug3("start over, passed a different list");
1.20 markus 1028: authmethod_clear();
1029: authlist_current = xstrdup(authlist);
1030: authlist_working = xstrdup(authlist);
1031: name = strtok_r(authlist_working, DELIM, &authlist_state);
1032: } else {
1033: /*
1034: * try to use previously used authentication method
1035: * or continue to use previously passed list
1036: */
1037: name = (authname_current != NULL) ?
1038: authname_current : strtok_r(NULL, DELIM, &authlist_state);
1.1 markus 1039: }
1.20 markus 1040:
1041: while (name != NULL) {
1.23 markus 1042: debug3("authmethod_lookup %s", name);
1.20 markus 1043: method = authmethod_lookup(name);
1.23 markus 1044: if (method != NULL && authmethod_is_enabled(method)) {
1045: debug3("authmethod_is_enabled %s", name);
1.20 markus 1046: break;
1.23 markus 1047: }
1.20 markus 1048: name = strtok_r(NULL, DELIM, &authlist_state);
1.23 markus 1049: method = NULL;
1.1 markus 1050: }
1051:
1.27 provos 1052: authname_old = authname_current;
1.23 markus 1053: if (method != NULL) {
1.20 markus 1054: debug("next auth method to try is %s", name);
1055: authname_current = xstrdup(name);
1056: } else {
1057: debug("no more auth methods to try");
1058: authname_current = NULL;
1.1 markus 1059: }
1.27 provos 1060:
1061: if (authname_old != NULL)
1062: xfree(authname_old);
1063:
1064: return (method);
1.1 markus 1065: }
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