blob: 8614b0b5b847e9146099dec71efc09c18aaa6b3c [file] [log] [blame]
Damien Millereba71ba2000-04-29 23:57:08 +10001/*
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.
Damien Millereba71ba2000-04-29 23:57:08 +100012 *
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"
Kevin Stevese27a5e02001-02-05 15:15:27 +000026RCSID("$OpenBSD: sshconnect2.c,v 1.41 2001/02/04 15:32:26 stevesk Exp $");
Damien Millereba71ba2000-04-29 23:57:08 +100027
28#include <openssl/bn.h>
Damien Millereba71ba2000-04-29 23:57:08 +100029#include <openssl/md5.h>
30#include <openssl/dh.h>
31#include <openssl/hmac.h>
32
33#include "ssh.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000034#include "ssh2.h"
Damien Millereba71ba2000-04-29 23:57:08 +100035#include "xmalloc.h"
36#include "rsa.h"
37#include "buffer.h"
38#include "packet.h"
Damien Millereba71ba2000-04-29 23:57:08 +100039#include "uidswap.h"
40#include "compat.h"
Damien Millereba71ba2000-04-29 23:57:08 +100041#include "bufaux.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000042#include "cipher.h"
Damien Millereba71ba2000-04-29 23:57:08 +100043#include "kex.h"
44#include "myproposal.h"
45#include "key.h"
Damien Millereba71ba2000-04-29 23:57:08 +100046#include "sshconnect.h"
47#include "authfile.h"
Damien Miller874d77b2000-10-14 16:23:11 +110048#include "cli.h"
Damien Miller62cee002000-09-23 17:15:56 +110049#include "dispatch.h"
Damien Millerad833b32000-08-23 10:46:23 +100050#include "authfd.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000051#include "log.h"
52#include "readconf.h"
53#include "readpass.h"
Damien Millereba71ba2000-04-29 23:57:08 +100054
Damien Miller874d77b2000-10-14 16:23:11 +110055void ssh_dh1_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *);
56void ssh_dhgex_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *);
57
Damien Millereba71ba2000-04-29 23:57:08 +100058/* import */
59extern char *client_version_string;
60extern char *server_version_string;
61extern Options options;
62
63/*
64 * SSH2 key exchange
65 */
66
Ben Lindstrom46c16222000-12-22 01:43:59 +000067u_char *session_id2 = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +100068int session_id2_len = 0;
69
70void
Damien Miller874d77b2000-10-14 16:23:11 +110071ssh_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
Damien Millere39cacc2000-11-29 12:18:44 +110078 if (options.ciphers == (char *)-1) {
79 log("No valid ciphers for protocol version 2 given, using defaults.");
80 options.ciphers = NULL;
Damien Miller874d77b2000-10-14 16:23:11 +110081 }
82 if (options.ciphers != NULL) {
83 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
84 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
85 }
86 if (options.compression) {
87 myproposal[PROPOSAL_COMP_ALGS_CTOS] = "zlib";
88 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
89 } else {
90 myproposal[PROPOSAL_COMP_ALGS_CTOS] = "none";
91 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
92 }
93
94 /* buffers with raw kexinit messages */
95 server_kexinit = xmalloc(sizeof(*server_kexinit));
96 buffer_init(server_kexinit);
97 client_kexinit = kex_init(myproposal);
98
99 /* algorithm negotiation */
100 kex_exchange_kexinit(client_kexinit, server_kexinit, sprop);
101 kex = kex_choose_conf(myproposal, sprop, 0);
102 for (i = 0; i < PROPOSAL_MAX; i++)
103 xfree(sprop[i]);
104
105 /* server authentication and session key agreement */
106 switch(kex->kex_type) {
107 case DH_GRP1_SHA1:
108 ssh_dh1_client(kex, host, hostaddr,
109 client_kexinit, server_kexinit);
110 break;
111 case DH_GEX_SHA1:
112 ssh_dhgex_client(kex, host, hostaddr, client_kexinit,
113 server_kexinit);
114 break;
115 default:
116 fatal("Unsupported key exchange %d", kex->kex_type);
117 }
118
119 buffer_free(client_kexinit);
120 buffer_free(server_kexinit);
121 xfree(client_kexinit);
122 xfree(server_kexinit);
123
124 debug("Wait SSH2_MSG_NEWKEYS.");
125 packet_read_expect(&plen, SSH2_MSG_NEWKEYS);
126 packet_done();
127 debug("GOT SSH2_MSG_NEWKEYS.");
128
129 debug("send SSH2_MSG_NEWKEYS.");
130 packet_start(SSH2_MSG_NEWKEYS);
131 packet_send();
132 packet_write_wait();
133 debug("done: send SSH2_MSG_NEWKEYS.");
134
135#ifdef DEBUG_KEXDH
136 /* send 1st encrypted/maced/compressed message */
137 packet_start(SSH2_MSG_IGNORE);
138 packet_put_cstring("markus");
139 packet_send();
140 packet_write_wait();
141#endif
142 debug("done: KEX2.");
143}
144
145/* diffie-hellman-group1-sha1 */
146
147void
Kevin Stevesef4eea92001-02-05 12:42:17 +0000148ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr,
Damien Miller874d77b2000-10-14 16:23:11 +1100149 Buffer *client_kexinit, Buffer *server_kexinit)
Damien Millereba71ba2000-04-29 23:57:08 +1000150{
Damien Miller62cee002000-09-23 17:15:56 +1100151#ifdef DEBUG_KEXDH
152 int i;
153#endif
Damien Millerb1715dc2000-05-30 13:44:51 +1000154 int plen, dlen;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000155 u_int klen, kout;
Damien Millereba71ba2000-04-29 23:57:08 +1000156 char *signature = NULL;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000157 u_int slen;
Damien Millereba71ba2000-04-29 23:57:08 +1000158 char *server_host_key_blob = NULL;
159 Key *server_host_key;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000160 u_int sbloblen;
Damien Millereba71ba2000-04-29 23:57:08 +1000161 DH *dh;
162 BIGNUM *dh_server_pub = 0;
163 BIGNUM *shared_secret = 0;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000164 u_char *kbuf;
165 u_char *hash;
Damien Millereba71ba2000-04-29 23:57:08 +1000166
Damien Millereba71ba2000-04-29 23:57:08 +1000167 debug("Sending SSH2_MSG_KEXDH_INIT.");
Damien Millereba71ba2000-04-29 23:57:08 +1000168 /* generate and send 'e', client DH public key */
169 dh = dh_new_group1();
Kevin Steves6b875862000-12-15 23:31:01 +0000170 dh_gen_key(dh);
Damien Millereba71ba2000-04-29 23:57:08 +1000171 packet_start(SSH2_MSG_KEXDH_INIT);
172 packet_put_bignum2(dh->pub_key);
173 packet_send();
174 packet_write_wait();
175
176#ifdef DEBUG_KEXDH
177 fprintf(stderr, "\np= ");
Damien Miller62cee002000-09-23 17:15:56 +1100178 BN_print_fp(stderr, dh->p);
Damien Millereba71ba2000-04-29 23:57:08 +1000179 fprintf(stderr, "\ng= ");
Damien Miller62cee002000-09-23 17:15:56 +1100180 BN_print_fp(stderr, dh->g);
Damien Millereba71ba2000-04-29 23:57:08 +1000181 fprintf(stderr, "\npub= ");
Damien Miller62cee002000-09-23 17:15:56 +1100182 BN_print_fp(stderr, dh->pub_key);
Damien Millereba71ba2000-04-29 23:57:08 +1000183 fprintf(stderr, "\n");
184 DHparams_print_fp(stderr, dh);
185#endif
186
187 debug("Wait SSH2_MSG_KEXDH_REPLY.");
188
Damien Millerb1715dc2000-05-30 13:44:51 +1000189 packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY);
Damien Millereba71ba2000-04-29 23:57:08 +1000190
191 debug("Got SSH2_MSG_KEXDH_REPLY.");
192
193 /* key, cert */
194 server_host_key_blob = packet_get_string(&sbloblen);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100195 server_host_key = key_from_blob(server_host_key_blob, sbloblen);
Damien Millereba71ba2000-04-29 23:57:08 +1000196 if (server_host_key == NULL)
197 fatal("cannot decode server_host_key_blob");
198
199 check_host_key(host, hostaddr, server_host_key,
Damien Miller874d77b2000-10-14 16:23:11 +1100200 options.user_hostfile2, options.system_hostfile2);
Damien Millereba71ba2000-04-29 23:57:08 +1000201
202 /* DH paramter f, server public DH key */
203 dh_server_pub = BN_new();
204 if (dh_server_pub == NULL)
205 fatal("dh_server_pub == NULL");
206 packet_get_bignum2(dh_server_pub, &dlen);
207
208#ifdef DEBUG_KEXDH
209 fprintf(stderr, "\ndh_server_pub= ");
Damien Miller62cee002000-09-23 17:15:56 +1100210 BN_print_fp(stderr, dh_server_pub);
Damien Millereba71ba2000-04-29 23:57:08 +1000211 fprintf(stderr, "\n");
212 debug("bits %d", BN_num_bits(dh_server_pub));
213#endif
214
215 /* signed H */
216 signature = packet_get_string(&slen);
217 packet_done();
218
219 if (!dh_pub_is_valid(dh, dh_server_pub))
220 packet_disconnect("bad server public DH value");
221
222 klen = DH_size(dh);
223 kbuf = xmalloc(klen);
224 kout = DH_compute_key(kbuf, dh_server_pub, dh);
225#ifdef DEBUG_KEXDH
226 debug("shared secret: len %d/%d", klen, kout);
227 fprintf(stderr, "shared secret == ");
228 for (i = 0; i< kout; i++)
229 fprintf(stderr, "%02x", (kbuf[i])&0xff);
230 fprintf(stderr, "\n");
231#endif
232 shared_secret = BN_new();
233
234 BN_bin2bn(kbuf, kout, shared_secret);
235 memset(kbuf, 0, klen);
236 xfree(kbuf);
237
238 /* calc and verify H */
239 hash = kex_hash(
240 client_version_string,
241 server_version_string,
242 buffer_ptr(client_kexinit), buffer_len(client_kexinit),
243 buffer_ptr(server_kexinit), buffer_len(server_kexinit),
244 server_host_key_blob, sbloblen,
245 dh->pub_key,
246 dh_server_pub,
247 shared_secret
248 );
249 xfree(server_host_key_blob);
Damien Millerb1715dc2000-05-30 13:44:51 +1000250 DH_free(dh);
Ben Lindstromb1985f72001-01-23 00:19:15 +0000251 BN_free(dh_server_pub);
Damien Millereba71ba2000-04-29 23:57:08 +1000252#ifdef DEBUG_KEXDH
253 fprintf(stderr, "hash == ");
254 for (i = 0; i< 20; i++)
255 fprintf(stderr, "%02x", (hash[i])&0xff);
256 fprintf(stderr, "\n");
257#endif
Ben Lindstrom46c16222000-12-22 01:43:59 +0000258 if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100259 fatal("key_verify failed for server_host_key");
Damien Millereba71ba2000-04-29 23:57:08 +1000260 key_free(server_host_key);
Ben Lindstromb1985f72001-01-23 00:19:15 +0000261 xfree(signature);
Damien Millereba71ba2000-04-29 23:57:08 +1000262
263 kex_derive_keys(kex, hash, shared_secret);
Ben Lindstromb1985f72001-01-23 00:19:15 +0000264 BN_clear_free(shared_secret);
Damien Millereba71ba2000-04-29 23:57:08 +1000265 packet_set_kex(kex);
266
Damien Millereba71ba2000-04-29 23:57:08 +1000267 /* save session id */
268 session_id2_len = 20;
269 session_id2 = xmalloc(session_id2_len);
270 memcpy(session_id2, hash, session_id2_len);
Damien Millerb1715dc2000-05-30 13:44:51 +1000271}
272
Damien Miller874d77b2000-10-14 16:23:11 +1100273/* diffie-hellman-group-exchange-sha1 */
274
275/*
276 * Estimates the group order for a Diffie-Hellman group that has an
277 * attack complexity approximately the same as O(2**bits). Estimate
278 * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3)))
279 */
280
281int
282dh_estimate(int bits)
Damien Millerb1715dc2000-05-30 13:44:51 +1000283{
Kevin Stevesef4eea92001-02-05 12:42:17 +0000284
Damien Miller874d77b2000-10-14 16:23:11 +1100285 if (bits < 64)
286 return (512); /* O(2**63) */
287 if (bits < 128)
288 return (1024); /* O(2**86) */
289 if (bits < 192)
290 return (2048); /* O(2**116) */
291 return (4096); /* O(2**156) */
292}
Damien Millerb1715dc2000-05-30 13:44:51 +1000293
Damien Miller874d77b2000-10-14 16:23:11 +1100294void
295ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr,
296 Buffer *client_kexinit, Buffer *server_kexinit)
297{
298#ifdef DEBUG_KEXDH
299 int i;
300#endif
301 int plen, dlen;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000302 u_int klen, kout;
Damien Miller874d77b2000-10-14 16:23:11 +1100303 char *signature = NULL;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000304 u_int slen, nbits;
Damien Miller874d77b2000-10-14 16:23:11 +1100305 char *server_host_key_blob = NULL;
306 Key *server_host_key;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000307 u_int sbloblen;
Damien Miller874d77b2000-10-14 16:23:11 +1100308 DH *dh;
309 BIGNUM *dh_server_pub = 0;
310 BIGNUM *shared_secret = 0;
311 BIGNUM *p = 0, *g = 0;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000312 u_char *kbuf;
313 u_char *hash;
Damien Millerb1715dc2000-05-30 13:44:51 +1000314
Damien Miller874d77b2000-10-14 16:23:11 +1100315 nbits = dh_estimate(kex->enc[MODE_OUT].cipher->key_len * 8);
Damien Millerb1715dc2000-05-30 13:44:51 +1000316
Damien Miller874d77b2000-10-14 16:23:11 +1100317 debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST.");
318 packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST);
319 packet_put_int(nbits);
Damien Millereba71ba2000-04-29 23:57:08 +1000320 packet_send();
321 packet_write_wait();
Damien Millereba71ba2000-04-29 23:57:08 +1000322
323#ifdef DEBUG_KEXDH
Damien Miller874d77b2000-10-14 16:23:11 +1100324 fprintf(stderr, "\nnbits = %d", nbits);
325#endif
326
327 debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP.");
328
329 packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP);
330
331 debug("Got SSH2_MSG_KEX_DH_GEX_GROUP.");
332
333 if ((p = BN_new()) == NULL)
334 fatal("BN_new");
335 packet_get_bignum2(p, &dlen);
336 if ((g = BN_new()) == NULL)
337 fatal("BN_new");
338 packet_get_bignum2(g, &dlen);
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000339 dh = dh_new_group(g, p);
Damien Miller874d77b2000-10-14 16:23:11 +1100340
Kevin Steves6b875862000-12-15 23:31:01 +0000341 dh_gen_key(dh);
342
Damien Miller874d77b2000-10-14 16:23:11 +1100343#ifdef DEBUG_KEXDH
344 fprintf(stderr, "\np= ");
345 BN_print_fp(stderr, dh->p);
346 fprintf(stderr, "\ng= ");
347 BN_print_fp(stderr, dh->g);
348 fprintf(stderr, "\npub= ");
349 BN_print_fp(stderr, dh->pub_key);
350 fprintf(stderr, "\n");
351 DHparams_print_fp(stderr, dh);
352#endif
353
354 debug("Sending SSH2_MSG_KEX_DH_GEX_INIT.");
355 /* generate and send 'e', client DH public key */
356 packet_start(SSH2_MSG_KEX_DH_GEX_INIT);
357 packet_put_bignum2(dh->pub_key);
Damien Millereba71ba2000-04-29 23:57:08 +1000358 packet_send();
359 packet_write_wait();
Damien Miller874d77b2000-10-14 16:23:11 +1100360
361 debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY.");
362
363 packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY);
364
365 debug("Got SSH2_MSG_KEXDH_REPLY.");
366
367 /* key, cert */
368 server_host_key_blob = packet_get_string(&sbloblen);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100369 server_host_key = key_from_blob(server_host_key_blob, sbloblen);
Damien Miller874d77b2000-10-14 16:23:11 +1100370 if (server_host_key == NULL)
371 fatal("cannot decode server_host_key_blob");
372
373 check_host_key(host, hostaddr, server_host_key,
374 options.user_hostfile2, options.system_hostfile2);
375
376 /* DH paramter f, server public DH key */
377 dh_server_pub = BN_new();
378 if (dh_server_pub == NULL)
379 fatal("dh_server_pub == NULL");
380 packet_get_bignum2(dh_server_pub, &dlen);
381
382#ifdef DEBUG_KEXDH
383 fprintf(stderr, "\ndh_server_pub= ");
384 BN_print_fp(stderr, dh_server_pub);
385 fprintf(stderr, "\n");
386 debug("bits %d", BN_num_bits(dh_server_pub));
Damien Millereba71ba2000-04-29 23:57:08 +1000387#endif
Damien Miller874d77b2000-10-14 16:23:11 +1100388
389 /* signed H */
390 signature = packet_get_string(&slen);
391 packet_done();
392
393 if (!dh_pub_is_valid(dh, dh_server_pub))
394 packet_disconnect("bad server public DH value");
395
396 klen = DH_size(dh);
397 kbuf = xmalloc(klen);
398 kout = DH_compute_key(kbuf, dh_server_pub, dh);
399#ifdef DEBUG_KEXDH
400 debug("shared secret: len %d/%d", klen, kout);
401 fprintf(stderr, "shared secret == ");
402 for (i = 0; i< kout; i++)
403 fprintf(stderr, "%02x", (kbuf[i])&0xff);
404 fprintf(stderr, "\n");
405#endif
406 shared_secret = BN_new();
407
408 BN_bin2bn(kbuf, kout, shared_secret);
409 memset(kbuf, 0, klen);
410 xfree(kbuf);
411
412 /* calc and verify H */
413 hash = kex_hash_gex(
414 client_version_string,
415 server_version_string,
416 buffer_ptr(client_kexinit), buffer_len(client_kexinit),
417 buffer_ptr(server_kexinit), buffer_len(server_kexinit),
418 server_host_key_blob, sbloblen,
Kevin Stevesef4eea92001-02-05 12:42:17 +0000419 nbits, dh->p, dh->g,
Damien Miller874d77b2000-10-14 16:23:11 +1100420 dh->pub_key,
421 dh_server_pub,
422 shared_secret
423 );
424 xfree(server_host_key_blob);
425 DH_free(dh);
Ben Lindstromb1985f72001-01-23 00:19:15 +0000426 BN_free(dh_server_pub);
Damien Miller874d77b2000-10-14 16:23:11 +1100427#ifdef DEBUG_KEXDH
428 fprintf(stderr, "hash == ");
429 for (i = 0; i< 20; i++)
430 fprintf(stderr, "%02x", (hash[i])&0xff);
431 fprintf(stderr, "\n");
432#endif
Ben Lindstrom46c16222000-12-22 01:43:59 +0000433 if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100434 fatal("key_verify failed for server_host_key");
Damien Miller874d77b2000-10-14 16:23:11 +1100435 key_free(server_host_key);
Ben Lindstromb1985f72001-01-23 00:19:15 +0000436 xfree(signature);
Damien Miller874d77b2000-10-14 16:23:11 +1100437
438 kex_derive_keys(kex, hash, shared_secret);
Ben Lindstromb1985f72001-01-23 00:19:15 +0000439 BN_clear_free(shared_secret);
Damien Miller874d77b2000-10-14 16:23:11 +1100440 packet_set_kex(kex);
441
442 /* save session id */
443 session_id2_len = 20;
444 session_id2 = xmalloc(session_id2_len);
445 memcpy(session_id2, hash, session_id2_len);
Damien Millereba71ba2000-04-29 23:57:08 +1000446}
Damien Millerb1715dc2000-05-30 13:44:51 +1000447
Damien Millereba71ba2000-04-29 23:57:08 +1000448/*
449 * Authenticate user
450 */
Damien Miller62cee002000-09-23 17:15:56 +1100451
452typedef struct Authctxt Authctxt;
453typedef struct Authmethod Authmethod;
454
455typedef int sign_cb_fn(
456 Authctxt *authctxt, Key *key,
Ben Lindstrom46c16222000-12-22 01:43:59 +0000457 u_char **sigp, int *lenp, u_char *data, int datalen);
Damien Miller62cee002000-09-23 17:15:56 +1100458
459struct Authctxt {
460 const char *server_user;
461 const char *host;
462 const char *service;
463 AuthenticationConnection *agent;
Damien Miller62cee002000-09-23 17:15:56 +1100464 Authmethod *method;
Damien Miller874d77b2000-10-14 16:23:11 +1100465 int success;
Damien Miller62cee002000-09-23 17:15:56 +1100466};
467struct Authmethod {
468 char *name; /* string to compare against server's list */
469 int (*userauth)(Authctxt *authctxt);
470 int *enabled; /* flag in option struct that enables method */
471 int *batch_flag; /* flag in option struct that disables method */
472};
473
474void input_userauth_success(int type, int plen, void *ctxt);
475void input_userauth_failure(int type, int plen, void *ctxt);
Ben Lindstromd26dcf32001-01-06 15:18:16 +0000476void input_userauth_banner(int type, int plen, void *ctxt);
Damien Miller62cee002000-09-23 17:15:56 +1100477void input_userauth_error(int type, int plen, void *ctxt);
Damien Miller874d77b2000-10-14 16:23:11 +1100478void input_userauth_info_req(int type, int plen, void *ctxt);
479
480int userauth_none(Authctxt *authctxt);
Damien Miller62cee002000-09-23 17:15:56 +1100481int userauth_pubkey(Authctxt *authctxt);
482int userauth_passwd(Authctxt *authctxt);
Damien Miller874d77b2000-10-14 16:23:11 +1100483int userauth_kbdint(Authctxt *authctxt);
Damien Miller62cee002000-09-23 17:15:56 +1100484
Ben Lindstrom46c16222000-12-22 01:43:59 +0000485void authmethod_clear(void);
Damien Miller874d77b2000-10-14 16:23:11 +1100486Authmethod *authmethod_get(char *authlist);
487Authmethod *authmethod_lookup(const char *name);
Damien Miller62cee002000-09-23 17:15:56 +1100488
489Authmethod authmethods[] = {
490 {"publickey",
491 userauth_pubkey,
Damien Miller0bc1bd82000-11-13 22:57:25 +1100492 &options.pubkey_authentication,
Damien Miller62cee002000-09-23 17:15:56 +1100493 NULL},
494 {"password",
495 userauth_passwd,
496 &options.password_authentication,
497 &options.batch_mode},
Damien Miller874d77b2000-10-14 16:23:11 +1100498 {"keyboard-interactive",
499 userauth_kbdint,
500 &options.kbd_interactive_authentication,
501 &options.batch_mode},
502 {"none",
503 userauth_none,
504 NULL,
505 NULL},
Damien Miller62cee002000-09-23 17:15:56 +1100506 {NULL, NULL, NULL, NULL}
507};
508
509void
510ssh_userauth2(const char *server_user, char *host)
511{
512 Authctxt authctxt;
513 int type;
514 int plen;
515
Ben Lindstrom95fb2dd2001-01-23 03:12:10 +0000516 if (options.challenge_reponse_authentication)
517 options.kbd_interactive_authentication = 1;
518
Damien Miller62cee002000-09-23 17:15:56 +1100519 debug("send SSH2_MSG_SERVICE_REQUEST");
520 packet_start(SSH2_MSG_SERVICE_REQUEST);
521 packet_put_cstring("ssh-userauth");
522 packet_send();
523 packet_write_wait();
524 type = packet_read(&plen);
525 if (type != SSH2_MSG_SERVICE_ACCEPT) {
526 fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
527 }
528 if (packet_remaining() > 0) {
529 char *reply = packet_get_string(&plen);
530 debug("service_accept: %s", reply);
531 xfree(reply);
Damien Miller62cee002000-09-23 17:15:56 +1100532 } else {
533 debug("buggy server: service_accept w/o service");
534 }
535 packet_done();
536 debug("got SSH2_MSG_SERVICE_ACCEPT");
537
538 /* setup authentication context */
539 authctxt.agent = ssh_get_authentication_connection();
540 authctxt.server_user = server_user;
541 authctxt.host = host;
542 authctxt.service = "ssh-connection"; /* service name */
543 authctxt.success = 0;
Damien Miller874d77b2000-10-14 16:23:11 +1100544 authctxt.method = authmethod_lookup("none");
545 if (authctxt.method == NULL)
546 fatal("ssh_userauth2: internal error: cannot send userauth none request");
547 authmethod_clear();
Damien Miller62cee002000-09-23 17:15:56 +1100548
549 /* initial userauth request */
Damien Miller874d77b2000-10-14 16:23:11 +1100550 userauth_none(&authctxt);
Damien Miller62cee002000-09-23 17:15:56 +1100551
552 dispatch_init(&input_userauth_error);
553 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
554 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
Ben Lindstromd26dcf32001-01-06 15:18:16 +0000555 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
Damien Miller62cee002000-09-23 17:15:56 +1100556 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
557
558 if (authctxt.agent != NULL)
559 ssh_close_authentication_connection(authctxt.agent);
560
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000561 debug("ssh-userauth2 successful: method %s", authctxt.method->name);
Damien Miller62cee002000-09-23 17:15:56 +1100562}
563void
564input_userauth_error(int type, int plen, void *ctxt)
565{
Ben Lindstromd26dcf32001-01-06 15:18:16 +0000566 fatal("input_userauth_error: bad message during authentication: "
567 "type %d", type);
568}
569void
570input_userauth_banner(int type, int plen, void *ctxt)
571{
572 char *msg, *lang;
573 debug3("input_userauth_banner");
574 msg = packet_get_string(NULL);
575 lang = packet_get_string(NULL);
576 fprintf(stderr, "%s", msg);
577 xfree(msg);
578 xfree(lang);
Damien Miller62cee002000-09-23 17:15:56 +1100579}
580void
581input_userauth_success(int type, int plen, void *ctxt)
582{
583 Authctxt *authctxt = ctxt;
584 if (authctxt == NULL)
585 fatal("input_userauth_success: no authentication context");
586 authctxt->success = 1; /* break out */
587}
588void
589input_userauth_failure(int type, int plen, void *ctxt)
590{
591 Authmethod *method = NULL;
592 Authctxt *authctxt = ctxt;
593 char *authlist = NULL;
594 int partial;
Damien Miller62cee002000-09-23 17:15:56 +1100595
596 if (authctxt == NULL)
597 fatal("input_userauth_failure: no authentication context");
598
Damien Miller874d77b2000-10-14 16:23:11 +1100599 authlist = packet_get_string(NULL);
Damien Miller62cee002000-09-23 17:15:56 +1100600 partial = packet_get_char();
601 packet_done();
602
603 if (partial != 0)
604 debug("partial success");
605 debug("authentications that can continue: %s", authlist);
606
607 for (;;) {
Damien Miller62cee002000-09-23 17:15:56 +1100608 method = authmethod_get(authlist);
609 if (method == NULL)
Kevin Stevesef4eea92001-02-05 12:42:17 +0000610 fatal("Unable to find an authentication method");
Damien Miller874d77b2000-10-14 16:23:11 +1100611 authctxt->method = method;
Damien Miller62cee002000-09-23 17:15:56 +1100612 if (method->userauth(authctxt) != 0) {
Damien Miller874d77b2000-10-14 16:23:11 +1100613 debug2("we sent a %s packet, wait for reply", method->name);
Damien Miller62cee002000-09-23 17:15:56 +1100614 break;
615 } else {
616 debug2("we did not send a packet, disable method");
617 method->enabled = NULL;
618 }
Kevin Stevesef4eea92001-02-05 12:42:17 +0000619 }
Damien Miller62cee002000-09-23 17:15:56 +1100620 xfree(authlist);
621}
622
Damien Millereba71ba2000-04-29 23:57:08 +1000623int
Damien Miller874d77b2000-10-14 16:23:11 +1100624userauth_none(Authctxt *authctxt)
625{
626 /* initial userauth request */
627 packet_start(SSH2_MSG_USERAUTH_REQUEST);
628 packet_put_cstring(authctxt->server_user);
629 packet_put_cstring(authctxt->service);
630 packet_put_cstring(authctxt->method->name);
631 packet_send();
632 packet_write_wait();
633 return 1;
634}
635
636int
Damien Miller62cee002000-09-23 17:15:56 +1100637userauth_passwd(Authctxt *authctxt)
Damien Millereba71ba2000-04-29 23:57:08 +1000638{
Damien Millere247cc42000-05-07 12:03:14 +1000639 static int attempt = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000640 char prompt[80];
641 char *password;
642
Damien Millerd3a18572000-06-07 19:55:44 +1000643 if (attempt++ >= options.number_of_password_prompts)
Damien Millere247cc42000-05-07 12:03:14 +1000644 return 0;
645
Damien Millerd3a18572000-06-07 19:55:44 +1000646 if(attempt != 1)
647 error("Permission denied, please try again.");
648
Damien Millereba71ba2000-04-29 23:57:08 +1000649 snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ",
Damien Miller62cee002000-09-23 17:15:56 +1100650 authctxt->server_user, authctxt->host);
Damien Millereba71ba2000-04-29 23:57:08 +1000651 password = read_passphrase(prompt, 0);
652 packet_start(SSH2_MSG_USERAUTH_REQUEST);
Damien Miller62cee002000-09-23 17:15:56 +1100653 packet_put_cstring(authctxt->server_user);
654 packet_put_cstring(authctxt->service);
Damien Miller874d77b2000-10-14 16:23:11 +1100655 packet_put_cstring(authctxt->method->name);
Damien Millereba71ba2000-04-29 23:57:08 +1000656 packet_put_char(0);
657 packet_put_cstring(password);
658 memset(password, 0, strlen(password));
659 xfree(password);
660 packet_send();
661 packet_write_wait();
662 return 1;
663}
664
Damien Millerad833b32000-08-23 10:46:23 +1000665int
Damien Miller62cee002000-09-23 17:15:56 +1100666sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
Damien Millereba71ba2000-04-29 23:57:08 +1000667{
668 Buffer b;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000669 u_char *blob, *signature;
Damien Millereba71ba2000-04-29 23:57:08 +1000670 int bloblen, slen;
Damien Miller6536c7d2000-06-22 21:32:31 +1000671 int skip = 0;
Damien Millerad833b32000-08-23 10:46:23 +1000672 int ret = -1;
Damien Miller874d77b2000-10-14 16:23:11 +1100673 int have_sig = 1;
Damien Millereba71ba2000-04-29 23:57:08 +1000674
Ben Lindstromd121f612000-12-03 17:00:47 +0000675 debug3("sign_and_send_pubkey");
Damien Miller0bc1bd82000-11-13 22:57:25 +1100676 if (key_to_blob(k, &blob, &bloblen) == 0) {
677 /* we cannot handle this key */
Ben Lindstromd121f612000-12-03 17:00:47 +0000678 debug3("sign_and_send_pubkey: cannot handle key");
Damien Miller0bc1bd82000-11-13 22:57:25 +1100679 return 0;
680 }
Damien Millereba71ba2000-04-29 23:57:08 +1000681 /* data to be signed */
682 buffer_init(&b);
Damien Miller50a41ed2000-10-16 12:14:42 +1100683 if (datafellows & SSH_OLD_SESSIONID) {
Damien Miller6536c7d2000-06-22 21:32:31 +1000684 buffer_append(&b, session_id2, session_id2_len);
Kevin Stevesef4eea92001-02-05 12:42:17 +0000685 skip = session_id2_len;
Damien Miller50a41ed2000-10-16 12:14:42 +1100686 } else {
687 buffer_put_string(&b, session_id2, session_id2_len);
688 skip = buffer_len(&b);
Damien Miller6536c7d2000-06-22 21:32:31 +1000689 }
Damien Millereba71ba2000-04-29 23:57:08 +1000690 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
Damien Miller62cee002000-09-23 17:15:56 +1100691 buffer_put_cstring(&b, authctxt->server_user);
Damien Miller30c3d422000-05-09 11:02:59 +1000692 buffer_put_cstring(&b,
Ben Lindstromd121f612000-12-03 17:00:47 +0000693 datafellows & SSH_BUG_PKSERVICE ?
Damien Miller30c3d422000-05-09 11:02:59 +1000694 "ssh-userauth" :
Damien Miller62cee002000-09-23 17:15:56 +1100695 authctxt->service);
Ben Lindstromd121f612000-12-03 17:00:47 +0000696 if (datafellows & SSH_BUG_PKAUTH) {
697 buffer_put_char(&b, have_sig);
698 } else {
699 buffer_put_cstring(&b, authctxt->method->name);
700 buffer_put_char(&b, have_sig);
Kevin Stevesef4eea92001-02-05 12:42:17 +0000701 buffer_put_cstring(&b, key_ssh_name(k));
Ben Lindstromd121f612000-12-03 17:00:47 +0000702 }
Damien Millereba71ba2000-04-29 23:57:08 +1000703 buffer_put_string(&b, blob, bloblen);
Damien Millereba71ba2000-04-29 23:57:08 +1000704
705 /* generate signature */
Damien Miller62cee002000-09-23 17:15:56 +1100706 ret = (*sign_callback)(authctxt, k, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
Damien Millerad833b32000-08-23 10:46:23 +1000707 if (ret == -1) {
708 xfree(blob);
709 buffer_free(&b);
710 return 0;
711 }
Damien Miller0bc1bd82000-11-13 22:57:25 +1100712#ifdef DEBUG_PK
Damien Millereba71ba2000-04-29 23:57:08 +1000713 buffer_dump(&b);
714#endif
Ben Lindstromd121f612000-12-03 17:00:47 +0000715 if (datafellows & SSH_BUG_PKSERVICE) {
Damien Miller30c3d422000-05-09 11:02:59 +1000716 buffer_clear(&b);
717 buffer_append(&b, session_id2, session_id2_len);
718 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
Damien Miller62cee002000-09-23 17:15:56 +1100719 buffer_put_cstring(&b, authctxt->server_user);
720 buffer_put_cstring(&b, authctxt->service);
Damien Miller874d77b2000-10-14 16:23:11 +1100721 buffer_put_cstring(&b, authctxt->method->name);
722 buffer_put_char(&b, have_sig);
Ben Lindstromd121f612000-12-03 17:00:47 +0000723 if (!(datafellows & SSH_BUG_PKAUTH))
Kevin Stevesef4eea92001-02-05 12:42:17 +0000724 buffer_put_cstring(&b, key_ssh_name(k));
Damien Miller30c3d422000-05-09 11:02:59 +1000725 buffer_put_string(&b, blob, bloblen);
726 }
727 xfree(blob);
Damien Millereba71ba2000-04-29 23:57:08 +1000728 /* append signature */
729 buffer_put_string(&b, signature, slen);
730 xfree(signature);
731
732 /* skip session id and packet type */
Damien Miller6536c7d2000-06-22 21:32:31 +1000733 if (buffer_len(&b) < skip + 1)
Damien Miller62cee002000-09-23 17:15:56 +1100734 fatal("userauth_pubkey: internal error");
Damien Miller6536c7d2000-06-22 21:32:31 +1000735 buffer_consume(&b, skip + 1);
Damien Millereba71ba2000-04-29 23:57:08 +1000736
737 /* put remaining data from buffer into packet */
738 packet_start(SSH2_MSG_USERAUTH_REQUEST);
739 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
740 buffer_free(&b);
741
742 /* send */
743 packet_send();
744 packet_write_wait();
Damien Millerad833b32000-08-23 10:46:23 +1000745
746 return 1;
Damien Miller994cf142000-07-21 10:19:44 +1000747}
748
Damien Miller62cee002000-09-23 17:15:56 +1100749/* sign callback */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000750int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
751 u_char *data, int datalen)
Damien Miller62cee002000-09-23 17:15:56 +1100752{
Damien Miller0bc1bd82000-11-13 22:57:25 +1100753 return key_sign(key, sigp, lenp, data, datalen);
Damien Miller62cee002000-09-23 17:15:56 +1100754}
755
Damien Miller994cf142000-07-21 10:19:44 +1000756int
Damien Miller62cee002000-09-23 17:15:56 +1100757userauth_pubkey_identity(Authctxt *authctxt, char *filename)
Damien Miller994cf142000-07-21 10:19:44 +1000758{
759 Key *k;
Damien Miller62cee002000-09-23 17:15:56 +1100760 int i, ret, try_next;
Damien Miller994cf142000-07-21 10:19:44 +1000761 struct stat st;
762
763 if (stat(filename, &st) != 0) {
764 debug("key does not exist: %s", filename);
765 return 0;
766 }
767 debug("try pubkey: %s", filename);
768
Damien Miller0bc1bd82000-11-13 22:57:25 +1100769 k = key_new(KEY_UNSPEC);
Damien Miller994cf142000-07-21 10:19:44 +1000770 if (!load_private_key(filename, "", k, NULL)) {
771 int success = 0;
772 char *passphrase;
773 char prompt[300];
774 snprintf(prompt, sizeof prompt,
Damien Miller0bc1bd82000-11-13 22:57:25 +1100775 "Enter passphrase for key '%.100s': ", filename);
Damien Miller62cee002000-09-23 17:15:56 +1100776 for (i = 0; i < options.number_of_password_prompts; i++) {
777 passphrase = read_passphrase(prompt, 0);
778 if (strcmp(passphrase, "") != 0) {
779 success = load_private_key(filename, passphrase, k, NULL);
780 try_next = 0;
781 } else {
782 debug2("no passphrase given, try next key");
783 try_next = 1;
784 }
785 memset(passphrase, 0, strlen(passphrase));
786 xfree(passphrase);
787 if (success || try_next)
788 break;
789 debug2("bad passphrase given, try again...");
790 }
Damien Miller994cf142000-07-21 10:19:44 +1000791 if (!success) {
792 key_free(k);
793 return 0;
794 }
795 }
Damien Miller0bc1bd82000-11-13 22:57:25 +1100796 ret = sign_and_send_pubkey(authctxt, k, key_sign_cb);
Damien Millerad833b32000-08-23 10:46:23 +1000797 key_free(k);
798 return ret;
799}
800
Damien Miller62cee002000-09-23 17:15:56 +1100801/* sign callback */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000802int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
803 u_char *data, int datalen)
Damien Millerad833b32000-08-23 10:46:23 +1000804{
Damien Miller62cee002000-09-23 17:15:56 +1100805 return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
Damien Millerad833b32000-08-23 10:46:23 +1000806}
807
808int
Damien Miller62cee002000-09-23 17:15:56 +1100809userauth_pubkey_agent(Authctxt *authctxt)
Damien Millerad833b32000-08-23 10:46:23 +1000810{
811 static int called = 0;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100812 int ret = 0;
Damien Millerad833b32000-08-23 10:46:23 +1000813 char *comment;
814 Key *k;
Damien Millerad833b32000-08-23 10:46:23 +1000815
816 if (called == 0) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100817 if (ssh_get_num_identities(authctxt->agent, 2) == 0)
818 debug2("userauth_pubkey_agent: no keys at all");
Damien Miller62cee002000-09-23 17:15:56 +1100819 called = 1;
Damien Millerad833b32000-08-23 10:46:23 +1000820 }
Damien Miller0bc1bd82000-11-13 22:57:25 +1100821 k = ssh_get_next_identity(authctxt->agent, &comment, 2);
Damien Miller62cee002000-09-23 17:15:56 +1100822 if (k == NULL) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100823 debug2("userauth_pubkey_agent: no more keys");
824 } else {
825 debug("userauth_pubkey_agent: trying agent key %s", comment);
826 xfree(comment);
827 ret = sign_and_send_pubkey(authctxt, k, agent_sign_cb);
828 key_free(k);
Damien Miller62cee002000-09-23 17:15:56 +1100829 }
Damien Miller0bc1bd82000-11-13 22:57:25 +1100830 if (ret == 0)
831 debug2("userauth_pubkey_agent: no message sent");
Damien Millerad833b32000-08-23 10:46:23 +1000832 return ret;
Damien Millereba71ba2000-04-29 23:57:08 +1000833}
834
Damien Miller62cee002000-09-23 17:15:56 +1100835int
836userauth_pubkey(Authctxt *authctxt)
Damien Millereba71ba2000-04-29 23:57:08 +1000837{
Damien Miller62cee002000-09-23 17:15:56 +1100838 static int idx = 0;
839 int sent = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000840
Damien Miller0bc1bd82000-11-13 22:57:25 +1100841 if (authctxt->agent != NULL) {
842 do {
843 sent = userauth_pubkey_agent(authctxt);
844 } while(!sent && authctxt->agent->howmany > 0);
845 }
846 while (!sent && idx < options.num_identity_files) {
847 if (options.identity_files_type[idx] != KEY_RSA1)
848 sent = userauth_pubkey_identity(authctxt,
849 options.identity_files[idx]);
850 idx++;
851 }
Damien Miller62cee002000-09-23 17:15:56 +1100852 return sent;
853}
Damien Millereba71ba2000-04-29 23:57:08 +1000854
Damien Miller874d77b2000-10-14 16:23:11 +1100855/*
856 * Send userauth request message specifying keyboard-interactive method.
857 */
858int
859userauth_kbdint(Authctxt *authctxt)
860{
861 static int attempt = 0;
862
863 if (attempt++ >= options.number_of_password_prompts)
864 return 0;
865
866 debug2("userauth_kbdint");
867 packet_start(SSH2_MSG_USERAUTH_REQUEST);
868 packet_put_cstring(authctxt->server_user);
869 packet_put_cstring(authctxt->service);
870 packet_put_cstring(authctxt->method->name);
871 packet_put_cstring(""); /* lang */
872 packet_put_cstring(options.kbd_interactive_devices ?
873 options.kbd_interactive_devices : "");
874 packet_send();
875 packet_write_wait();
876
877 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
878 return 1;
879}
880
881/*
882 * parse SSH2_MSG_USERAUTH_INFO_REQUEST, prompt user and send
883 * SSH2_MSG_USERAUTH_INFO_RESPONSE
884 */
885void
886input_userauth_info_req(int type, int plen, void *ctxt)
887{
888 Authctxt *authctxt = ctxt;
889 char *name = NULL;
890 char *inst = NULL;
891 char *lang = NULL;
892 char *prompt = NULL;
893 char *response = NULL;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000894 u_int num_prompts, i;
Damien Miller874d77b2000-10-14 16:23:11 +1100895 int echo = 0;
896
897 debug2("input_userauth_info_req");
898
899 if (authctxt == NULL)
900 fatal("input_userauth_info_req: no authentication context");
901
902 name = packet_get_string(NULL);
903 inst = packet_get_string(NULL);
904 lang = packet_get_string(NULL);
905
906 if (strlen(name) > 0)
907 cli_mesg(name);
908 xfree(name);
909
910 if (strlen(inst) > 0)
911 cli_mesg(inst);
912 xfree(inst);
913 xfree(lang); /* unused */
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
931 packet_put_cstring(response);
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}
Damien Miller62cee002000-09-23 17:15:56 +1100941
942/* find auth method */
943
944#define DELIM ","
945
946static char *def_authlist = "publickey,password";
947static char *authlist_current = NULL; /* clean copy used for comparison */
948static char *authname_current = NULL; /* last used auth method */
949static char *authlist_working = NULL; /* copy that gets modified by strtok_r() */
950static 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 */
957void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000958authmethod_clear(void)
Damien Miller62cee002000-09-23 17:15:56 +1100959{
960 if (authlist_current != NULL) {
961 xfree(authlist_current);
962 authlist_current = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000963 }
Damien Miller62cee002000-09-23 17:15:56 +1100964 if (authlist_working != NULL) {
965 xfree(authlist_working);
966 authlist_working = NULL;
967 }
968 if (authname_current != NULL) {
969 xfree(authname_current);
970 authlist_state = NULL;
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 */
981int
982authmethod_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
995Authmethod *
996authmethod_lookup(const char *name)
997{
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}
1006
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.
Kevin Stevesef4eea92001-02-05 12:42:17 +00001013 */
Damien Miller62cee002000-09-23 17:15:56 +11001014
1015Authmethod *
1016authmethod_get(char *authlist)
1017{
Damien Miller69b69aa2000-10-28 14:19:58 +11001018 char *name = NULL, *authname_old;
Damien Miller62cee002000-09-23 17:15:56 +11001019 Authmethod *method = NULL;
Kevin Stevesef4eea92001-02-05 12:42:17 +00001020
Damien Miller62cee002000-09-23 17:15:56 +11001021 /* 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 */
Damien Miller874d77b2000-10-14 16:23:11 +11001027 debug3("start over, passed a different list");
Damien Miller62cee002000-09-23 17:15:56 +11001028 authmethod_clear();
1029 authlist_current = xstrdup(authlist);
1030 authlist_working = xstrdup(authlist);
1031 name = strtok_r(authlist_working, DELIM, &authlist_state);
Damien Millereba71ba2000-04-29 23:57:08 +10001032 } else {
Damien Miller62cee002000-09-23 17:15:56 +11001033 /*
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);
Damien Millereba71ba2000-04-29 23:57:08 +10001039 }
Damien Millereba71ba2000-04-29 23:57:08 +10001040
Damien Miller62cee002000-09-23 17:15:56 +11001041 while (name != NULL) {
Damien Miller874d77b2000-10-14 16:23:11 +11001042 debug3("authmethod_lookup %s", name);
Damien Miller62cee002000-09-23 17:15:56 +11001043 method = authmethod_lookup(name);
Damien Miller874d77b2000-10-14 16:23:11 +11001044 if (method != NULL && authmethod_is_enabled(method)) {
1045 debug3("authmethod_is_enabled %s", name);
Damien Millereba71ba2000-04-29 23:57:08 +10001046 break;
Damien Miller874d77b2000-10-14 16:23:11 +11001047 }
Damien Miller62cee002000-09-23 17:15:56 +11001048 name = strtok_r(NULL, DELIM, &authlist_state);
Damien Miller874d77b2000-10-14 16:23:11 +11001049 method = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +10001050 }
Damien Miller62cee002000-09-23 17:15:56 +11001051
Damien Miller69b69aa2000-10-28 14:19:58 +11001052 authname_old = authname_current;
Damien Miller874d77b2000-10-14 16:23:11 +11001053 if (method != NULL) {
Damien Miller62cee002000-09-23 17:15:56 +11001054 debug("next auth method to try is %s", name);
1055 authname_current = xstrdup(name);
Damien Miller62cee002000-09-23 17:15:56 +11001056 } else {
1057 debug("no more auth methods to try");
1058 authname_current = NULL;
Damien Miller62cee002000-09-23 17:15:56 +11001059 }
Damien Miller69b69aa2000-10-28 14:19:58 +11001060
1061 if (authname_old != NULL)
1062 xfree(authname_old);
1063
1064 return (method);
Damien Millereba71ba2000-04-29 23:57:08 +10001065}