2 * Copyright (c) 2000 Markus Friedl. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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.
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.
26 RCSID("$OpenBSD: sshconnect2.c,v 1.59 2001/03/29 14:24:59 provos Exp $");
28 #include <openssl/bn.h>
29 #include <openssl/md5.h>
30 #include <openssl/dh.h>
31 #include <openssl/hmac.h>
44 #include "myproposal.h"
46 #include "sshconnect.h"
57 void ssh_dh1_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *);
58 void ssh_dhgex_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *);
61 extern char *client_version_string;
62 extern char *server_version_string;
63 extern Options options;
69 u_char *session_id2 = NULL;
70 int session_id2_len = 0;
73 ssh_kex2(char *host, struct sockaddr *hostaddr)
77 Buffer *client_kexinit, *server_kexinit;
78 char *sprop[PROPOSAL_MAX];
80 if (options.ciphers == (char *)-1) {
81 log("No valid ciphers for protocol version 2 given, using defaults.");
82 options.ciphers = NULL;
84 if (options.ciphers != NULL) {
85 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
86 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
88 if (options.compression) {
89 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
90 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
92 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
93 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
95 if (options.macs != NULL) {
96 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
97 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
100 myproposal[PROPOSAL_ENC_ALGS_STOC] =
101 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
103 /* buffers with raw kexinit messages */
104 server_kexinit = xmalloc(sizeof(*server_kexinit));
105 buffer_init(server_kexinit);
106 client_kexinit = kex_init(myproposal);
108 /* algorithm negotiation */
109 kex_exchange_kexinit(client_kexinit, server_kexinit, sprop);
110 kex = kex_choose_conf(myproposal, sprop, 0);
111 for (i = 0; i < PROPOSAL_MAX; i++)
114 /* server authentication and session key agreement */
115 switch(kex->kex_type) {
117 ssh_dh1_client(kex, host, hostaddr,
118 client_kexinit, server_kexinit);
121 ssh_dhgex_client(kex, host, hostaddr, client_kexinit,
125 fatal("Unsupported key exchange %d", kex->kex_type);
128 buffer_free(client_kexinit);
129 buffer_free(server_kexinit);
130 xfree(client_kexinit);
131 xfree(server_kexinit);
133 debug("Wait SSH2_MSG_NEWKEYS.");
134 packet_read_expect(&plen, SSH2_MSG_NEWKEYS);
136 debug("GOT SSH2_MSG_NEWKEYS.");
138 debug("send SSH2_MSG_NEWKEYS.");
139 packet_start(SSH2_MSG_NEWKEYS);
142 debug("done: send SSH2_MSG_NEWKEYS.");
145 /* send 1st encrypted/maced/compressed message */
146 packet_start(SSH2_MSG_IGNORE);
147 packet_put_cstring("markus");
151 debug("done: KEX2.");
154 /* diffie-hellman-group1-sha1 */
157 ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr,
158 Buffer *client_kexinit, Buffer *server_kexinit)
165 char *signature = NULL;
167 char *server_host_key_blob = NULL;
168 Key *server_host_key;
171 BIGNUM *dh_server_pub = 0;
172 BIGNUM *shared_secret = 0;
176 debug("Sending SSH2_MSG_KEXDH_INIT.");
177 /* generate and send 'e', client DH public key */
178 dh = dh_new_group1();
179 dh_gen_key(dh, kex->we_need * 8);
180 packet_start(SSH2_MSG_KEXDH_INIT);
181 packet_put_bignum2(dh->pub_key);
186 fprintf(stderr, "\np= ");
187 BN_print_fp(stderr, dh->p);
188 fprintf(stderr, "\ng= ");
189 BN_print_fp(stderr, dh->g);
190 fprintf(stderr, "\npub= ");
191 BN_print_fp(stderr, dh->pub_key);
192 fprintf(stderr, "\n");
193 DHparams_print_fp(stderr, dh);
196 debug("Wait SSH2_MSG_KEXDH_REPLY.");
198 packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY);
200 debug("Got SSH2_MSG_KEXDH_REPLY.");
203 server_host_key_blob = packet_get_string(&sbloblen);
204 server_host_key = key_from_blob(server_host_key_blob, sbloblen);
205 if (server_host_key == NULL)
206 fatal("cannot decode server_host_key_blob");
208 check_host_key(host, hostaddr, server_host_key,
209 options.user_hostfile2, options.system_hostfile2);
211 /* DH paramter f, server public DH key */
212 dh_server_pub = BN_new();
213 if (dh_server_pub == NULL)
214 fatal("dh_server_pub == NULL");
215 packet_get_bignum2(dh_server_pub, &dlen);
218 fprintf(stderr, "\ndh_server_pub= ");
219 BN_print_fp(stderr, dh_server_pub);
220 fprintf(stderr, "\n");
221 debug("bits %d", BN_num_bits(dh_server_pub));
225 signature = packet_get_string(&slen);
228 if (!dh_pub_is_valid(dh, dh_server_pub))
229 packet_disconnect("bad server public DH value");
232 kbuf = xmalloc(klen);
233 kout = DH_compute_key(kbuf, dh_server_pub, dh);
235 debug("shared secret: len %d/%d", klen, kout);
236 fprintf(stderr, "shared secret == ");
237 for (i = 0; i< kout; i++)
238 fprintf(stderr, "%02x", (kbuf[i])&0xff);
239 fprintf(stderr, "\n");
241 shared_secret = BN_new();
243 BN_bin2bn(kbuf, kout, shared_secret);
244 memset(kbuf, 0, klen);
247 /* calc and verify H */
249 client_version_string,
250 server_version_string,
251 buffer_ptr(client_kexinit), buffer_len(client_kexinit),
252 buffer_ptr(server_kexinit), buffer_len(server_kexinit),
253 server_host_key_blob, sbloblen,
258 xfree(server_host_key_blob);
260 BN_free(dh_server_pub);
262 fprintf(stderr, "hash == ");
263 for (i = 0; i< 20; i++)
264 fprintf(stderr, "%02x", (hash[i])&0xff);
265 fprintf(stderr, "\n");
267 if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
268 fatal("key_verify failed for server_host_key");
269 key_free(server_host_key);
272 kex_derive_keys(kex, hash, shared_secret);
273 BN_clear_free(shared_secret);
276 /* save session id */
277 session_id2_len = 20;
278 session_id2 = xmalloc(session_id2_len);
279 memcpy(session_id2, hash, session_id2_len);
282 /* diffie-hellman-group-exchange-sha1 */
285 * Estimates the group order for a Diffie-Hellman group that has an
286 * attack complexity approximately the same as O(2**bits). Estimate
287 * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3)))
291 dh_estimate(int bits)
295 return (512); /* O(2**63) */
297 return (1024); /* O(2**86) */
299 return (2048); /* O(2**116) */
300 return (4096); /* O(2**156) */
304 ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr,
305 Buffer *client_kexinit, Buffer *server_kexinit)
312 char *signature = NULL;
313 u_int slen, nbits, min, max;
314 char *server_host_key_blob = NULL;
315 Key *server_host_key;
318 BIGNUM *dh_server_pub = 0;
319 BIGNUM *shared_secret = 0;
320 BIGNUM *p = 0, *g = 0;
324 nbits = dh_estimate(kex->we_need * 8);
326 if (datafellows & SSH_OLD_DHGEX) {
327 debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST_OLD.");
329 /* Old GEX request */
330 packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
331 packet_put_int(nbits);
335 debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST.");
337 /* New GEX request */
341 packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST);
343 packet_put_int(nbits);
350 fprintf(stderr, "\nmin = %d, nbits = %d, max = %d", min, nbits, max);
353 debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP.");
355 packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP);
357 debug("Got SSH2_MSG_KEX_DH_GEX_GROUP.");
359 if ((p = BN_new()) == NULL)
361 packet_get_bignum2(p, &dlen);
362 if ((g = BN_new()) == NULL)
364 packet_get_bignum2(g, &dlen);
366 if (BN_num_bits(p) < min || BN_num_bits(p) > max)
367 fatal("DH_GEX group out of range: %d !< %d !< %d",
368 min, BN_num_bits(p), max);
370 dh = dh_new_group(g, p);
372 dh_gen_key(dh, kex->we_need * 8);
375 fprintf(stderr, "\np= ");
376 BN_print_fp(stderr, dh->p);
377 fprintf(stderr, "\ng= ");
378 BN_print_fp(stderr, dh->g);
379 fprintf(stderr, "\npub= ");
380 BN_print_fp(stderr, dh->pub_key);
381 fprintf(stderr, "\n");
382 DHparams_print_fp(stderr, dh);
385 debug("Sending SSH2_MSG_KEX_DH_GEX_INIT.");
386 /* generate and send 'e', client DH public key */
387 packet_start(SSH2_MSG_KEX_DH_GEX_INIT);
388 packet_put_bignum2(dh->pub_key);
392 debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY.");
394 packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY);
396 debug("Got SSH2_MSG_KEXDH_REPLY.");
399 server_host_key_blob = packet_get_string(&sbloblen);
400 server_host_key = key_from_blob(server_host_key_blob, sbloblen);
401 if (server_host_key == NULL)
402 fatal("cannot decode server_host_key_blob");
404 check_host_key(host, hostaddr, server_host_key,
405 options.user_hostfile2, options.system_hostfile2);
407 /* DH paramter f, server public DH key */
408 dh_server_pub = BN_new();
409 if (dh_server_pub == NULL)
410 fatal("dh_server_pub == NULL");
411 packet_get_bignum2(dh_server_pub, &dlen);
414 fprintf(stderr, "\ndh_server_pub= ");
415 BN_print_fp(stderr, dh_server_pub);
416 fprintf(stderr, "\n");
417 debug("bits %d", BN_num_bits(dh_server_pub));
421 signature = packet_get_string(&slen);
424 if (!dh_pub_is_valid(dh, dh_server_pub))
425 packet_disconnect("bad server public DH value");
428 kbuf = xmalloc(klen);
429 kout = DH_compute_key(kbuf, dh_server_pub, dh);
431 debug("shared secret: len %d/%d", klen, kout);
432 fprintf(stderr, "shared secret == ");
433 for (i = 0; i< kout; i++)
434 fprintf(stderr, "%02x", (kbuf[i])&0xff);
435 fprintf(stderr, "\n");
437 shared_secret = BN_new();
439 BN_bin2bn(kbuf, kout, shared_secret);
440 memset(kbuf, 0, klen);
443 if (datafellows & SSH_OLD_DHGEX) {
444 /* These values are not included in the hash */
449 /* calc and verify H */
451 client_version_string,
452 server_version_string,
453 buffer_ptr(client_kexinit), buffer_len(client_kexinit),
454 buffer_ptr(server_kexinit), buffer_len(server_kexinit),
455 server_host_key_blob, sbloblen,
462 xfree(server_host_key_blob);
464 BN_free(dh_server_pub);
466 fprintf(stderr, "hash == ");
467 for (i = 0; i< 20; i++)
468 fprintf(stderr, "%02x", (hash[i])&0xff);
469 fprintf(stderr, "\n");
471 if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
472 fatal("key_verify failed for server_host_key");
473 key_free(server_host_key);
476 kex_derive_keys(kex, hash, shared_secret);
477 BN_clear_free(shared_secret);
480 /* save session id */
481 session_id2_len = 20;
482 session_id2 = xmalloc(session_id2_len);
483 memcpy(session_id2, hash, session_id2_len);
490 typedef struct Authctxt Authctxt;
491 typedef struct Authmethod Authmethod;
493 typedef int sign_cb_fn(
494 Authctxt *authctxt, Key *key,
495 u_char **sigp, int *lenp, u_char *data, int datalen);
498 const char *server_user;
501 AuthenticationConnection *agent;
506 sign_cb_fn *last_key_sign;
510 char *name; /* string to compare against server's list */
511 int (*userauth)(Authctxt *authctxt);
512 int *enabled; /* flag in option struct that enables method */
513 int *batch_flag; /* flag in option struct that disables method */
516 void input_userauth_success(int type, int plen, void *ctxt);
517 void input_userauth_failure(int type, int plen, void *ctxt);
518 void input_userauth_banner(int type, int plen, void *ctxt);
519 void input_userauth_error(int type, int plen, void *ctxt);
520 void input_userauth_info_req(int type, int plen, void *ctxt);
521 void input_userauth_pk_ok(int type, int plen, void *ctxt);
523 int userauth_none(Authctxt *authctxt);
524 int userauth_pubkey(Authctxt *authctxt);
525 int userauth_passwd(Authctxt *authctxt);
526 int userauth_kbdint(Authctxt *authctxt);
528 void userauth(Authctxt *authctxt, char *authlist);
531 sign_and_send_pubkey(Authctxt *authctxt, Key *k,
532 sign_cb_fn *sign_callback);
533 void clear_auth_state(Authctxt *authctxt);
535 Authmethod *authmethod_get(char *authlist);
536 Authmethod *authmethod_lookup(const char *name);
537 char *authmethods_get(void);
539 Authmethod authmethods[] = {
542 &options.pubkey_authentication,
546 &options.password_authentication,
547 &options.batch_mode},
548 {"keyboard-interactive",
550 &options.kbd_interactive_authentication,
551 &options.batch_mode},
556 {NULL, NULL, NULL, NULL}
560 ssh_userauth2(const char *server_user, char *host)
566 if (options.challenge_reponse_authentication)
567 options.kbd_interactive_authentication = 1;
569 debug("send SSH2_MSG_SERVICE_REQUEST");
570 packet_start(SSH2_MSG_SERVICE_REQUEST);
571 packet_put_cstring("ssh-userauth");
574 type = packet_read(&plen);
575 if (type != SSH2_MSG_SERVICE_ACCEPT) {
576 fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
578 if (packet_remaining() > 0) {
579 char *reply = packet_get_string(&plen);
580 debug("service_accept: %s", reply);
583 debug("buggy server: service_accept w/o service");
586 debug("got SSH2_MSG_SERVICE_ACCEPT");
588 if (options.preferred_authentications == NULL)
589 options.preferred_authentications = authmethods_get();
591 /* setup authentication context */
592 authctxt.agent = ssh_get_authentication_connection();
593 authctxt.server_user = server_user;
594 authctxt.host = host;
595 authctxt.service = "ssh-connection"; /* service name */
596 authctxt.success = 0;
597 authctxt.method = authmethod_lookup("none");
598 authctxt.authlist = NULL;
599 if (authctxt.method == NULL)
600 fatal("ssh_userauth2: internal error: cannot send userauth none request");
602 /* initial userauth request */
603 userauth_none(&authctxt);
605 dispatch_init(&input_userauth_error);
606 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
607 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
608 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
609 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
611 if (authctxt.agent != NULL)
612 ssh_close_authentication_connection(authctxt.agent);
614 debug("ssh-userauth2 successful: method %s", authctxt.method->name);
617 userauth(Authctxt *authctxt, char *authlist)
619 if (authlist == NULL) {
620 authlist = authctxt->authlist;
622 if (authctxt->authlist)
623 xfree(authctxt->authlist);
624 authctxt->authlist = authlist;
627 Authmethod *method = authmethod_get(authlist);
629 fatal("Permission denied (%s).", authlist);
630 authctxt->method = method;
631 if (method->userauth(authctxt) != 0) {
632 debug2("we sent a %s packet, wait for reply", method->name);
635 debug2("we did not send a packet, disable method");
636 method->enabled = NULL;
641 input_userauth_error(int type, int plen, void *ctxt)
643 fatal("input_userauth_error: bad message during authentication: "
647 input_userauth_banner(int type, int plen, void *ctxt)
650 debug3("input_userauth_banner");
651 msg = packet_get_string(NULL);
652 lang = packet_get_string(NULL);
653 fprintf(stderr, "%s", msg);
658 input_userauth_success(int type, int plen, void *ctxt)
660 Authctxt *authctxt = ctxt;
661 if (authctxt == NULL)
662 fatal("input_userauth_success: no authentication context");
663 if (authctxt->authlist)
664 xfree(authctxt->authlist);
665 clear_auth_state(authctxt);
666 authctxt->success = 1; /* break out */
669 input_userauth_failure(int type, int plen, void *ctxt)
671 Authctxt *authctxt = ctxt;
672 char *authlist = NULL;
675 if (authctxt == NULL)
676 fatal("input_userauth_failure: no authentication context");
678 authlist = packet_get_string(NULL);
679 partial = packet_get_char();
683 log("Authenticated with partial success.");
684 debug("authentications that can continue: %s", authlist);
686 clear_auth_state(authctxt);
687 userauth(authctxt, authlist);
690 input_userauth_pk_ok(int type, int plen, void *ctxt)
692 Authctxt *authctxt = ctxt;
695 int alen, blen, pktype, sent = 0;
696 char *pkalg, *pkblob, *fp;
698 if (authctxt == NULL)
699 fatal("input_userauth_pk_ok: no authentication context");
700 if (datafellows & SSH_BUG_PKOK) {
701 /* this is similar to SSH_BUG_PKAUTH */
702 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
703 pkblob = packet_get_string(&blen);
705 buffer_append(&b, pkblob, blen);
706 pkalg = buffer_get_string(&b, &alen);
709 pkalg = packet_get_string(&alen);
710 pkblob = packet_get_string(&blen);
714 debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
715 pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
718 if (authctxt->last_key == NULL ||
719 authctxt->last_key_sign == NULL) {
720 debug("no last key or no sign cb");
723 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
724 debug("unknown pkalg %s", pkalg);
727 if ((key = key_from_blob(pkblob, blen)) == NULL) {
728 debug("no key from blob. pkalg %s", pkalg);
731 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
732 debug2("input_userauth_pk_ok: fp %s", fp);
734 if (!key_equal(key, authctxt->last_key)) {
735 debug("key != last_key");
738 sent = sign_and_send_pubkey(authctxt, key,
739 authctxt->last_key_sign);
748 clear_auth_state(authctxt);
749 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
751 /* try another method if we did not send a packet*/
753 userauth(authctxt, NULL);
758 userauth_none(Authctxt *authctxt)
760 /* initial userauth request */
761 packet_start(SSH2_MSG_USERAUTH_REQUEST);
762 packet_put_cstring(authctxt->server_user);
763 packet_put_cstring(authctxt->service);
764 packet_put_cstring(authctxt->method->name);
770 userauth_passwd(Authctxt *authctxt)
772 static int attempt = 0;
776 if (attempt++ >= options.number_of_password_prompts)
780 error("Permission denied, please try again.");
782 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
783 authctxt->server_user, authctxt->host);
784 password = read_passphrase(prompt, 0);
785 packet_start(SSH2_MSG_USERAUTH_REQUEST);
786 packet_put_cstring(authctxt->server_user);
787 packet_put_cstring(authctxt->service);
788 packet_put_cstring(authctxt->method->name);
790 packet_put_cstring(password);
791 memset(password, 0, strlen(password));
793 packet_inject_ignore(64);
799 clear_auth_state(Authctxt *authctxt)
801 /* XXX clear authentication state */
802 if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
803 debug3("clear_auth_state: key_free %p", authctxt->last_key);
804 key_free(authctxt->last_key);
806 authctxt->last_key = NULL;
807 authctxt->last_key_hint = -2;
808 authctxt->last_key_sign = NULL;
812 sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
815 u_char *blob, *signature;
821 debug3("sign_and_send_pubkey");
823 if (key_to_blob(k, &blob, &bloblen) == 0) {
824 /* we cannot handle this key */
825 debug3("sign_and_send_pubkey: cannot handle key");
828 /* data to be signed */
830 if (datafellows & SSH_OLD_SESSIONID) {
831 buffer_append(&b, session_id2, session_id2_len);
832 skip = session_id2_len;
834 buffer_put_string(&b, session_id2, session_id2_len);
835 skip = buffer_len(&b);
837 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
838 buffer_put_cstring(&b, authctxt->server_user);
839 buffer_put_cstring(&b,
840 datafellows & SSH_BUG_PKSERVICE ?
843 if (datafellows & SSH_BUG_PKAUTH) {
844 buffer_put_char(&b, have_sig);
846 buffer_put_cstring(&b, authctxt->method->name);
847 buffer_put_char(&b, have_sig);
848 buffer_put_cstring(&b, key_ssh_name(k));
850 buffer_put_string(&b, blob, bloblen);
852 /* generate signature */
853 ret = (*sign_callback)(authctxt, k, &signature, &slen,
854 buffer_ptr(&b), buffer_len(&b));
863 if (datafellows & SSH_BUG_PKSERVICE) {
865 buffer_append(&b, session_id2, session_id2_len);
866 skip = session_id2_len;
867 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
868 buffer_put_cstring(&b, authctxt->server_user);
869 buffer_put_cstring(&b, authctxt->service);
870 buffer_put_cstring(&b, authctxt->method->name);
871 buffer_put_char(&b, have_sig);
872 if (!(datafellows & SSH_BUG_PKAUTH))
873 buffer_put_cstring(&b, key_ssh_name(k));
874 buffer_put_string(&b, blob, bloblen);
878 /* append signature */
879 buffer_put_string(&b, signature, slen);
882 /* skip session id and packet type */
883 if (buffer_len(&b) < skip + 1)
884 fatal("userauth_pubkey: internal error");
885 buffer_consume(&b, skip + 1);
887 /* put remaining data from buffer into packet */
888 packet_start(SSH2_MSG_USERAUTH_REQUEST);
889 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
897 send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
901 int bloblen, have_sig = 0;
903 debug3("send_pubkey_test");
905 if (key_to_blob(k, &blob, &bloblen) == 0) {
906 /* we cannot handle this key */
907 debug3("send_pubkey_test: cannot handle key");
910 /* register callback for USERAUTH_PK_OK message */
911 authctxt->last_key_sign = sign_callback;
912 authctxt->last_key_hint = hint;
913 authctxt->last_key = k;
914 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
916 packet_start(SSH2_MSG_USERAUTH_REQUEST);
917 packet_put_cstring(authctxt->server_user);
918 packet_put_cstring(authctxt->service);
919 packet_put_cstring(authctxt->method->name);
920 packet_put_char(have_sig);
921 if (!(datafellows & SSH_BUG_PKAUTH))
922 packet_put_cstring(key_ssh_name(k));
923 packet_put_string(blob, bloblen);
930 load_identity_file(char *filename)
933 char prompt[300], *passphrase;
937 if (stat(filename, &st) < 0) {
938 debug3("no such identity: %s", filename);
941 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
942 if (private == NULL) {
943 if (options.batch_mode)
945 snprintf(prompt, sizeof prompt,
946 "Enter passphrase for key '%.100s': ", filename);
947 for (i = 0; i < options.number_of_password_prompts; i++) {
948 passphrase = read_passphrase(prompt, 0);
949 if (strcmp(passphrase, "") != 0) {
950 private = key_load_private_type(KEY_UNSPEC, filename,
954 debug2("no passphrase given, try next key");
957 memset(passphrase, 0, strlen(passphrase));
959 if (private != NULL || quit)
961 debug2("bad passphrase given, try again...");
968 identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
969 u_char *data, int datalen)
974 idx = authctxt->last_key_hint;
977 private = load_identity_file(options.identity_files[idx]);
980 ret = key_sign(private, sigp, lenp, data, datalen);
985 int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
986 u_char *data, int datalen)
988 return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
991 int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
992 u_char *data, int datalen)
994 return key_sign(key, sigp, lenp, data, datalen);
998 userauth_pubkey_agent(Authctxt *authctxt)
1000 static int called = 0;
1006 if (ssh_get_num_identities(authctxt->agent, 2) == 0)
1007 debug2("userauth_pubkey_agent: no keys at all");
1010 k = ssh_get_next_identity(authctxt->agent, &comment, 2);
1012 debug2("userauth_pubkey_agent: no more keys");
1014 debug("userauth_pubkey_agent: testing agent key %s", comment);
1016 ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
1021 debug2("userauth_pubkey_agent: no message sent");
1026 userauth_pubkey(Authctxt *authctxt)
1033 if (authctxt->agent != NULL) {
1035 sent = userauth_pubkey_agent(authctxt);
1036 } while(!sent && authctxt->agent->howmany > 0);
1038 while (!sent && idx < options.num_identity_files) {
1039 key = options.identity_keys[idx];
1040 filename = options.identity_files[idx];
1042 debug("try privkey: %s", filename);
1043 key = load_identity_file(filename);
1045 sent = sign_and_send_pubkey(authctxt, key,
1049 } else if (key->type != KEY_RSA1) {
1050 debug("try pubkey: %s", filename);
1051 sent = send_pubkey_test(authctxt, key,
1052 identity_sign_cb, idx);
1060 * Send userauth request message specifying keyboard-interactive method.
1063 userauth_kbdint(Authctxt *authctxt)
1065 static int attempt = 0;
1067 if (attempt++ >= options.number_of_password_prompts)
1070 debug2("userauth_kbdint");
1071 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1072 packet_put_cstring(authctxt->server_user);
1073 packet_put_cstring(authctxt->service);
1074 packet_put_cstring(authctxt->method->name);
1075 packet_put_cstring(""); /* lang */
1076 packet_put_cstring(options.kbd_interactive_devices ?
1077 options.kbd_interactive_devices : "");
1080 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1085 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1088 input_userauth_info_req(int type, int plen, void *ctxt)
1090 Authctxt *authctxt = ctxt;
1091 char *name, *inst, *lang, *prompt, *response;
1092 u_int num_prompts, i;
1095 debug2("input_userauth_info_req");
1097 if (authctxt == NULL)
1098 fatal("input_userauth_info_req: no authentication context");
1100 name = packet_get_string(NULL);
1101 inst = packet_get_string(NULL);
1102 lang = packet_get_string(NULL);
1103 if (strlen(name) > 0)
1105 if (strlen(inst) > 0)
1111 num_prompts = packet_get_int();
1113 * Begin to build info response packet based on prompts requested.
1114 * We commit to providing the correct number of responses, so if
1115 * further on we run into a problem that prevents this, we have to
1116 * be sure and clean this up and send a correct error response.
1118 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1119 packet_put_int(num_prompts);
1121 for (i = 0; i < num_prompts; i++) {
1122 prompt = packet_get_string(NULL);
1123 echo = packet_get_char();
1125 response = cli_prompt(prompt, echo);
1127 packet_put_cstring(response);
1128 memset(response, 0, strlen(response));
1132 packet_done(); /* done with parsing incoming message. */
1134 packet_inject_ignore(64);
1138 /* find auth method */
1141 * given auth method name, if configurable options permit this method fill
1142 * in auth_ident field and return true, otherwise return false.
1145 authmethod_is_enabled(Authmethod *method)
1149 /* return false if options indicate this method is disabled */
1150 if (method->enabled == NULL || *method->enabled == 0)
1152 /* return false if batch mode is enabled but method needs interactive mode */
1153 if (method->batch_flag != NULL && *method->batch_flag != 0)
1159 authmethod_lookup(const char *name)
1161 Authmethod *method = NULL;
1163 for (method = authmethods; method->name != NULL; method++)
1164 if (strcmp(name, method->name) == 0)
1166 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1170 /* XXX internal state */
1171 static Authmethod *current = NULL;
1172 static char *supported = NULL;
1173 static char *preferred = NULL;
1175 * Given the authentication method list sent by the server, return the
1176 * next method we should try. If the server initially sends a nil list,
1177 * use a built-in default list.
1180 authmethod_get(char *authlist)
1186 /* Use a suitable default if we're passed a nil list. */
1187 if (authlist == NULL || strlen(authlist) == 0)
1188 authlist = options.preferred_authentications;
1190 if (supported == NULL || strcmp(authlist, supported) != 0) {
1191 debug3("start over, passed a different list %s", authlist);
1192 if (supported != NULL)
1194 supported = xstrdup(authlist);
1195 preferred = options.preferred_authentications;
1196 debug3("preferred %s", preferred);
1198 } else if (current != NULL && authmethod_is_enabled(current))
1202 if ((name = match_list(preferred, supported, &next)) == NULL) {
1203 debug("no more auth methods to try");
1208 debug3("authmethod_lookup %s", name);
1209 debug3("remaining preferred: %s", preferred);
1210 if ((current = authmethod_lookup(name)) != NULL &&
1211 authmethod_is_enabled(current)) {
1212 debug3("authmethod_is_enabled %s", name);
1213 debug("next auth method to try is %s", name);
1222 authmethods_get(void)
1224 Authmethod *method = NULL;
1228 for (method = authmethods; method->name != NULL; method++) {
1229 if (authmethod_is_enabled(method)) {
1231 strlcat(buf, DELIM, sizeof buf);
1232 strlcat(buf, method->name, sizeof buf);
1235 return xstrdup(buf);