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 1.55 2001/03/23 11:04:07 djm 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"
56 void ssh_dh1_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *);
57 void ssh_dhgex_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *);
60 extern char *client_version_string;
61 extern char *server_version_string;
62 extern Options options;
68 u_char *session_id2 = NULL;
69 int session_id2_len = 0;
72 ssh_kex2(char *host, struct sockaddr *hostaddr)
76 Buffer *client_kexinit, *server_kexinit;
77 char *sprop[PROPOSAL_MAX];
79 if (options.ciphers == (char *)-1) {
80 log("No valid ciphers for protocol version 2 given, using defaults.");
81 options.ciphers = NULL;
83 if (options.ciphers != NULL) {
84 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
85 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
87 if (options.compression) {
88 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
89 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
91 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
92 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
94 if (options.macs != NULL) {
95 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
96 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
99 myproposal[PROPOSAL_ENC_ALGS_STOC] =
100 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
102 /* buffers with raw kexinit messages */
103 server_kexinit = xmalloc(sizeof(*server_kexinit));
104 buffer_init(server_kexinit);
105 client_kexinit = kex_init(myproposal);
107 /* algorithm negotiation */
108 kex_exchange_kexinit(client_kexinit, server_kexinit, sprop);
109 kex = kex_choose_conf(myproposal, sprop, 0);
110 for (i = 0; i < PROPOSAL_MAX; i++)
113 /* server authentication and session key agreement */
114 switch(kex->kex_type) {
116 ssh_dh1_client(kex, host, hostaddr,
117 client_kexinit, server_kexinit);
120 ssh_dhgex_client(kex, host, hostaddr, client_kexinit,
124 fatal("Unsupported key exchange %d", kex->kex_type);
127 buffer_free(client_kexinit);
128 buffer_free(server_kexinit);
129 xfree(client_kexinit);
130 xfree(server_kexinit);
132 debug("Wait SSH2_MSG_NEWKEYS.");
133 packet_read_expect(&plen, SSH2_MSG_NEWKEYS);
135 debug("GOT SSH2_MSG_NEWKEYS.");
137 debug("send SSH2_MSG_NEWKEYS.");
138 packet_start(SSH2_MSG_NEWKEYS);
141 debug("done: send SSH2_MSG_NEWKEYS.");
144 /* send 1st encrypted/maced/compressed message */
145 packet_start(SSH2_MSG_IGNORE);
146 packet_put_cstring("markus");
150 debug("done: KEX2.");
153 /* diffie-hellman-group1-sha1 */
156 ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr,
157 Buffer *client_kexinit, Buffer *server_kexinit)
164 char *signature = NULL;
166 char *server_host_key_blob = NULL;
167 Key *server_host_key;
170 BIGNUM *dh_server_pub = 0;
171 BIGNUM *shared_secret = 0;
175 debug("Sending SSH2_MSG_KEXDH_INIT.");
176 /* generate and send 'e', client DH public key */
177 dh = dh_new_group1();
178 dh_gen_key(dh, kex->we_need * 8);
179 packet_start(SSH2_MSG_KEXDH_INIT);
180 packet_put_bignum2(dh->pub_key);
185 fprintf(stderr, "\np= ");
186 BN_print_fp(stderr, dh->p);
187 fprintf(stderr, "\ng= ");
188 BN_print_fp(stderr, dh->g);
189 fprintf(stderr, "\npub= ");
190 BN_print_fp(stderr, dh->pub_key);
191 fprintf(stderr, "\n");
192 DHparams_print_fp(stderr, dh);
195 debug("Wait SSH2_MSG_KEXDH_REPLY.");
197 packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY);
199 debug("Got SSH2_MSG_KEXDH_REPLY.");
202 server_host_key_blob = packet_get_string(&sbloblen);
203 server_host_key = key_from_blob(server_host_key_blob, sbloblen);
204 if (server_host_key == NULL)
205 fatal("cannot decode server_host_key_blob");
207 check_host_key(host, hostaddr, server_host_key,
208 options.user_hostfile2, options.system_hostfile2);
210 /* DH paramter f, server public DH key */
211 dh_server_pub = BN_new();
212 if (dh_server_pub == NULL)
213 fatal("dh_server_pub == NULL");
214 packet_get_bignum2(dh_server_pub, &dlen);
217 fprintf(stderr, "\ndh_server_pub= ");
218 BN_print_fp(stderr, dh_server_pub);
219 fprintf(stderr, "\n");
220 debug("bits %d", BN_num_bits(dh_server_pub));
224 signature = packet_get_string(&slen);
227 if (!dh_pub_is_valid(dh, dh_server_pub))
228 packet_disconnect("bad server public DH value");
231 kbuf = xmalloc(klen);
232 kout = DH_compute_key(kbuf, dh_server_pub, dh);
234 debug("shared secret: len %d/%d", klen, kout);
235 fprintf(stderr, "shared secret == ");
236 for (i = 0; i< kout; i++)
237 fprintf(stderr, "%02x", (kbuf[i])&0xff);
238 fprintf(stderr, "\n");
240 shared_secret = BN_new();
242 BN_bin2bn(kbuf, kout, shared_secret);
243 memset(kbuf, 0, klen);
246 /* calc and verify H */
248 client_version_string,
249 server_version_string,
250 buffer_ptr(client_kexinit), buffer_len(client_kexinit),
251 buffer_ptr(server_kexinit), buffer_len(server_kexinit),
252 server_host_key_blob, sbloblen,
257 xfree(server_host_key_blob);
259 BN_free(dh_server_pub);
261 fprintf(stderr, "hash == ");
262 for (i = 0; i< 20; i++)
263 fprintf(stderr, "%02x", (hash[i])&0xff);
264 fprintf(stderr, "\n");
266 if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
267 fatal("key_verify failed for server_host_key");
268 key_free(server_host_key);
271 kex_derive_keys(kex, hash, shared_secret);
272 BN_clear_free(shared_secret);
275 /* save session id */
276 session_id2_len = 20;
277 session_id2 = xmalloc(session_id2_len);
278 memcpy(session_id2, hash, session_id2_len);
281 /* diffie-hellman-group-exchange-sha1 */
284 * Estimates the group order for a Diffie-Hellman group that has an
285 * attack complexity approximately the same as O(2**bits). Estimate
286 * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3)))
290 dh_estimate(int bits)
294 return (512); /* O(2**63) */
296 return (1024); /* O(2**86) */
298 return (2048); /* O(2**116) */
299 return (4096); /* O(2**156) */
303 ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr,
304 Buffer *client_kexinit, Buffer *server_kexinit)
311 char *signature = NULL;
313 char *server_host_key_blob = NULL;
314 Key *server_host_key;
317 BIGNUM *dh_server_pub = 0;
318 BIGNUM *shared_secret = 0;
319 BIGNUM *p = 0, *g = 0;
323 nbits = dh_estimate(kex->we_need * 8);
325 debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST.");
326 packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST);
327 packet_put_int(nbits);
332 fprintf(stderr, "\nnbits = %d", nbits);
335 debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP.");
337 packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP);
339 debug("Got SSH2_MSG_KEX_DH_GEX_GROUP.");
341 if ((p = BN_new()) == NULL)
343 packet_get_bignum2(p, &dlen);
344 if ((g = BN_new()) == NULL)
346 packet_get_bignum2(g, &dlen);
347 dh = dh_new_group(g, p);
349 dh_gen_key(dh, kex->we_need * 8);
352 fprintf(stderr, "\np= ");
353 BN_print_fp(stderr, dh->p);
354 fprintf(stderr, "\ng= ");
355 BN_print_fp(stderr, dh->g);
356 fprintf(stderr, "\npub= ");
357 BN_print_fp(stderr, dh->pub_key);
358 fprintf(stderr, "\n");
359 DHparams_print_fp(stderr, dh);
362 debug("Sending SSH2_MSG_KEX_DH_GEX_INIT.");
363 /* generate and send 'e', client DH public key */
364 packet_start(SSH2_MSG_KEX_DH_GEX_INIT);
365 packet_put_bignum2(dh->pub_key);
369 debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY.");
371 packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY);
373 debug("Got SSH2_MSG_KEXDH_REPLY.");
376 server_host_key_blob = packet_get_string(&sbloblen);
377 server_host_key = key_from_blob(server_host_key_blob, sbloblen);
378 if (server_host_key == NULL)
379 fatal("cannot decode server_host_key_blob");
381 check_host_key(host, hostaddr, server_host_key,
382 options.user_hostfile2, options.system_hostfile2);
384 /* DH paramter f, server public DH key */
385 dh_server_pub = BN_new();
386 if (dh_server_pub == NULL)
387 fatal("dh_server_pub == NULL");
388 packet_get_bignum2(dh_server_pub, &dlen);
391 fprintf(stderr, "\ndh_server_pub= ");
392 BN_print_fp(stderr, dh_server_pub);
393 fprintf(stderr, "\n");
394 debug("bits %d", BN_num_bits(dh_server_pub));
398 signature = packet_get_string(&slen);
401 if (!dh_pub_is_valid(dh, dh_server_pub))
402 packet_disconnect("bad server public DH value");
405 kbuf = xmalloc(klen);
406 kout = DH_compute_key(kbuf, dh_server_pub, dh);
408 debug("shared secret: len %d/%d", klen, kout);
409 fprintf(stderr, "shared secret == ");
410 for (i = 0; i< kout; i++)
411 fprintf(stderr, "%02x", (kbuf[i])&0xff);
412 fprintf(stderr, "\n");
414 shared_secret = BN_new();
416 BN_bin2bn(kbuf, kout, shared_secret);
417 memset(kbuf, 0, klen);
420 /* calc and verify H */
422 client_version_string,
423 server_version_string,
424 buffer_ptr(client_kexinit), buffer_len(client_kexinit),
425 buffer_ptr(server_kexinit), buffer_len(server_kexinit),
426 server_host_key_blob, sbloblen,
432 xfree(server_host_key_blob);
434 BN_free(dh_server_pub);
436 fprintf(stderr, "hash == ");
437 for (i = 0; i< 20; i++)
438 fprintf(stderr, "%02x", (hash[i])&0xff);
439 fprintf(stderr, "\n");
441 if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
442 fatal("key_verify failed for server_host_key");
443 key_free(server_host_key);
446 kex_derive_keys(kex, hash, shared_secret);
447 BN_clear_free(shared_secret);
450 /* save session id */
451 session_id2_len = 20;
452 session_id2 = xmalloc(session_id2_len);
453 memcpy(session_id2, hash, session_id2_len);
460 typedef struct Authctxt Authctxt;
461 typedef struct Authmethod Authmethod;
463 typedef int sign_cb_fn(
464 Authctxt *authctxt, Key *key,
465 u_char **sigp, int *lenp, u_char *data, int datalen);
468 const char *server_user;
471 AuthenticationConnection *agent;
476 sign_cb_fn *last_key_sign;
480 char *name; /* string to compare against server's list */
481 int (*userauth)(Authctxt *authctxt);
482 int *enabled; /* flag in option struct that enables method */
483 int *batch_flag; /* flag in option struct that disables method */
486 void input_userauth_success(int type, int plen, void *ctxt);
487 void input_userauth_failure(int type, int plen, void *ctxt);
488 void input_userauth_banner(int type, int plen, void *ctxt);
489 void input_userauth_error(int type, int plen, void *ctxt);
490 void input_userauth_info_req(int type, int plen, void *ctxt);
491 void input_userauth_pk_ok(int type, int plen, void *ctxt);
493 int userauth_none(Authctxt *authctxt);
494 int userauth_pubkey(Authctxt *authctxt);
495 int userauth_passwd(Authctxt *authctxt);
496 int userauth_kbdint(Authctxt *authctxt);
498 void userauth(Authctxt *authctxt, char *authlist);
501 sign_and_send_pubkey(Authctxt *authctxt, Key *k,
502 sign_cb_fn *sign_callback);
503 void clear_auth_state(Authctxt *authctxt);
505 Authmethod *authmethod_get(char *authlist);
506 Authmethod *authmethod_lookup(const char *name);
507 char *authmethods_get(void);
509 Authmethod authmethods[] = {
512 &options.pubkey_authentication,
516 &options.password_authentication,
517 &options.batch_mode},
518 {"keyboard-interactive",
520 &options.kbd_interactive_authentication,
521 &options.batch_mode},
526 {NULL, NULL, NULL, NULL}
530 ssh_userauth2(const char *server_user, char *host)
536 if (options.challenge_reponse_authentication)
537 options.kbd_interactive_authentication = 1;
539 debug("send SSH2_MSG_SERVICE_REQUEST");
540 packet_start(SSH2_MSG_SERVICE_REQUEST);
541 packet_put_cstring("ssh-userauth");
544 type = packet_read(&plen);
545 if (type != SSH2_MSG_SERVICE_ACCEPT) {
546 fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
548 if (packet_remaining() > 0) {
549 char *reply = packet_get_string(&plen);
550 debug("service_accept: %s", reply);
553 debug("buggy server: service_accept w/o service");
556 debug("got SSH2_MSG_SERVICE_ACCEPT");
558 if (options.preferred_authentications == NULL)
559 options.preferred_authentications = authmethods_get();
561 /* setup authentication context */
562 authctxt.agent = ssh_get_authentication_connection();
563 authctxt.server_user = server_user;
564 authctxt.host = host;
565 authctxt.service = "ssh-connection"; /* service name */
566 authctxt.success = 0;
567 authctxt.method = authmethod_lookup("none");
568 authctxt.authlist = NULL;
569 if (authctxt.method == NULL)
570 fatal("ssh_userauth2: internal error: cannot send userauth none request");
572 /* initial userauth request */
573 userauth_none(&authctxt);
575 dispatch_init(&input_userauth_error);
576 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
577 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
578 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
579 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
581 if (authctxt.agent != NULL)
582 ssh_close_authentication_connection(authctxt.agent);
584 debug("ssh-userauth2 successful: method %s", authctxt.method->name);
587 userauth(Authctxt *authctxt, char *authlist)
589 if (authlist == NULL) {
590 authlist = authctxt->authlist;
592 if (authctxt->authlist)
593 xfree(authctxt->authlist);
594 authctxt->authlist = authlist;
597 Authmethod *method = authmethod_get(authlist);
599 fatal("Permission denied (%s).", authlist);
600 authctxt->method = method;
601 if (method->userauth(authctxt) != 0) {
602 debug2("we sent a %s packet, wait for reply", method->name);
605 debug2("we did not send a packet, disable method");
606 method->enabled = NULL;
611 input_userauth_error(int type, int plen, void *ctxt)
613 fatal("input_userauth_error: bad message during authentication: "
617 input_userauth_banner(int type, int plen, void *ctxt)
620 debug3("input_userauth_banner");
621 msg = packet_get_string(NULL);
622 lang = packet_get_string(NULL);
623 fprintf(stderr, "%s", msg);
628 input_userauth_success(int type, int plen, void *ctxt)
630 Authctxt *authctxt = ctxt;
631 if (authctxt == NULL)
632 fatal("input_userauth_success: no authentication context");
633 if (authctxt->authlist)
634 xfree(authctxt->authlist);
635 clear_auth_state(authctxt);
636 authctxt->success = 1; /* break out */
639 input_userauth_failure(int type, int plen, void *ctxt)
641 Authctxt *authctxt = ctxt;
642 char *authlist = NULL;
645 if (authctxt == NULL)
646 fatal("input_userauth_failure: no authentication context");
648 authlist = packet_get_string(NULL);
649 partial = packet_get_char();
653 log("Authenticated with partial success.");
654 debug("authentications that can continue: %s", authlist);
656 clear_auth_state(authctxt);
657 userauth(authctxt, authlist);
660 input_userauth_pk_ok(int type, int plen, void *ctxt)
662 Authctxt *authctxt = ctxt;
665 int alen, blen, pktype, sent = 0;
666 char *pkalg, *pkblob, *fp;
668 if (authctxt == NULL)
669 fatal("input_userauth_pk_ok: no authentication context");
670 if (datafellows & SSH_BUG_PKOK) {
671 /* this is similar to SSH_BUG_PKAUTH */
672 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
673 pkblob = packet_get_string(&blen);
675 buffer_append(&b, pkblob, blen);
676 pkalg = buffer_get_string(&b, &alen);
679 pkalg = packet_get_string(&alen);
680 pkblob = packet_get_string(&blen);
684 debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
685 pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
688 if (authctxt->last_key == NULL ||
689 authctxt->last_key_sign == NULL) {
690 debug("no last key or no sign cb");
693 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
694 debug("unknown pkalg %s", pkalg);
697 if ((key = key_from_blob(pkblob, blen)) == NULL) {
698 debug("no key from blob. pkalg %s", pkalg);
701 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
702 debug2("input_userauth_pk_ok: fp %s", fp);
704 if (!key_equal(key, authctxt->last_key)) {
705 debug("key != last_key");
708 sent = sign_and_send_pubkey(authctxt, key,
709 authctxt->last_key_sign);
718 clear_auth_state(authctxt);
719 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
721 /* try another method if we did not send a packet*/
723 userauth(authctxt, NULL);
728 userauth_none(Authctxt *authctxt)
730 /* initial userauth request */
731 packet_start(SSH2_MSG_USERAUTH_REQUEST);
732 packet_put_cstring(authctxt->server_user);
733 packet_put_cstring(authctxt->service);
734 packet_put_cstring(authctxt->method->name);
740 userauth_passwd(Authctxt *authctxt)
742 static int attempt = 0;
746 if (attempt++ >= options.number_of_password_prompts)
750 error("Permission denied, please try again.");
752 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
753 authctxt->server_user, authctxt->host);
754 password = read_passphrase(prompt, 0);
755 packet_start(SSH2_MSG_USERAUTH_REQUEST);
756 packet_put_cstring(authctxt->server_user);
757 packet_put_cstring(authctxt->service);
758 packet_put_cstring(authctxt->method->name);
760 packet_put_cstring(password);
761 memset(password, 0, strlen(password));
763 packet_inject_ignore(64);
769 clear_auth_state(Authctxt *authctxt)
771 /* XXX clear authentication state */
772 if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
773 debug3("clear_auth_state: key_free %p", authctxt->last_key);
774 key_free(authctxt->last_key);
776 authctxt->last_key = NULL;
777 authctxt->last_key_hint = -2;
778 authctxt->last_key_sign = NULL;
782 sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
785 u_char *blob, *signature;
791 debug3("sign_and_send_pubkey");
793 if (key_to_blob(k, &blob, &bloblen) == 0) {
794 /* we cannot handle this key */
795 debug3("sign_and_send_pubkey: cannot handle key");
798 /* data to be signed */
800 if (datafellows & SSH_OLD_SESSIONID) {
801 buffer_append(&b, session_id2, session_id2_len);
802 skip = session_id2_len;
804 buffer_put_string(&b, session_id2, session_id2_len);
805 skip = buffer_len(&b);
807 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
808 buffer_put_cstring(&b, authctxt->server_user);
809 buffer_put_cstring(&b,
810 datafellows & SSH_BUG_PKSERVICE ?
813 if (datafellows & SSH_BUG_PKAUTH) {
814 buffer_put_char(&b, have_sig);
816 buffer_put_cstring(&b, authctxt->method->name);
817 buffer_put_char(&b, have_sig);
818 buffer_put_cstring(&b, key_ssh_name(k));
820 buffer_put_string(&b, blob, bloblen);
822 /* generate signature */
823 ret = (*sign_callback)(authctxt, k, &signature, &slen,
824 buffer_ptr(&b), buffer_len(&b));
833 if (datafellows & SSH_BUG_PKSERVICE) {
835 buffer_append(&b, session_id2, session_id2_len);
836 skip = session_id2_len;
837 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
838 buffer_put_cstring(&b, authctxt->server_user);
839 buffer_put_cstring(&b, authctxt->service);
840 buffer_put_cstring(&b, authctxt->method->name);
841 buffer_put_char(&b, have_sig);
842 if (!(datafellows & SSH_BUG_PKAUTH))
843 buffer_put_cstring(&b, key_ssh_name(k));
844 buffer_put_string(&b, blob, bloblen);
848 /* append signature */
849 buffer_put_string(&b, signature, slen);
852 /* skip session id and packet type */
853 if (buffer_len(&b) < skip + 1)
854 fatal("userauth_pubkey: internal error");
855 buffer_consume(&b, skip + 1);
857 /* put remaining data from buffer into packet */
858 packet_start(SSH2_MSG_USERAUTH_REQUEST);
859 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
867 send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
871 int bloblen, have_sig = 0;
873 debug3("send_pubkey_test");
875 if (key_to_blob(k, &blob, &bloblen) == 0) {
876 /* we cannot handle this key */
877 debug3("send_pubkey_test: cannot handle key");
880 /* register callback for USERAUTH_PK_OK message */
881 authctxt->last_key_sign = sign_callback;
882 authctxt->last_key_hint = hint;
883 authctxt->last_key = k;
884 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
886 packet_start(SSH2_MSG_USERAUTH_REQUEST);
887 packet_put_cstring(authctxt->server_user);
888 packet_put_cstring(authctxt->service);
889 packet_put_cstring(authctxt->method->name);
890 packet_put_char(have_sig);
891 if (!(datafellows & SSH_BUG_PKAUTH))
892 packet_put_cstring(key_ssh_name(k));
893 packet_put_string(blob, bloblen);
900 load_identity_file(char *filename)
903 char prompt[300], *passphrase;
904 int success = 0, quit, i;
907 if (stat(filename, &st) < 0) {
908 debug3("no such identity: %s", filename);
911 private = key_new(KEY_UNSPEC);
912 if (!load_private_key(filename, "", private, NULL)) {
913 if (options.batch_mode) {
917 snprintf(prompt, sizeof prompt,
918 "Enter passphrase for key '%.100s': ", filename);
919 for (i = 0; i < options.number_of_password_prompts; i++) {
920 passphrase = read_passphrase(prompt, 0);
921 if (strcmp(passphrase, "") != 0) {
922 success = load_private_key(filename,
923 passphrase, private, NULL);
926 debug2("no passphrase given, try next key");
929 memset(passphrase, 0, strlen(passphrase));
933 debug2("bad passphrase given, try again...");
944 identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
945 u_char *data, int datalen)
950 idx = authctxt->last_key_hint;
953 private = load_identity_file(options.identity_files[idx]);
956 ret = key_sign(private, sigp, lenp, data, datalen);
961 int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
962 u_char *data, int datalen)
964 return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
967 int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp,
968 u_char *data, int datalen)
970 return key_sign(key, sigp, lenp, data, datalen);
974 userauth_pubkey_agent(Authctxt *authctxt)
976 static int called = 0;
982 if (ssh_get_num_identities(authctxt->agent, 2) == 0)
983 debug2("userauth_pubkey_agent: no keys at all");
986 k = ssh_get_next_identity(authctxt->agent, &comment, 2);
988 debug2("userauth_pubkey_agent: no more keys");
990 debug("userauth_pubkey_agent: testing agent key %s", comment);
992 ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
997 debug2("userauth_pubkey_agent: no message sent");
1002 userauth_pubkey(Authctxt *authctxt)
1009 if (authctxt->agent != NULL) {
1011 sent = userauth_pubkey_agent(authctxt);
1012 } while(!sent && authctxt->agent->howmany > 0);
1014 while (!sent && idx < options.num_identity_files) {
1015 key = options.identity_keys[idx];
1016 filename = options.identity_files[idx];
1018 debug("try privkey: %s", filename);
1019 key = load_identity_file(filename);
1021 sent = sign_and_send_pubkey(authctxt, key,
1025 } else if (key->type != KEY_RSA1) {
1026 debug("try pubkey: %s", filename);
1027 sent = send_pubkey_test(authctxt, key,
1028 identity_sign_cb, idx);
1036 * Send userauth request message specifying keyboard-interactive method.
1039 userauth_kbdint(Authctxt *authctxt)
1041 static int attempt = 0;
1043 if (attempt++ >= options.number_of_password_prompts)
1046 debug2("userauth_kbdint");
1047 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1048 packet_put_cstring(authctxt->server_user);
1049 packet_put_cstring(authctxt->service);
1050 packet_put_cstring(authctxt->method->name);
1051 packet_put_cstring(""); /* lang */
1052 packet_put_cstring(options.kbd_interactive_devices ?
1053 options.kbd_interactive_devices : "");
1056 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1061 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1064 input_userauth_info_req(int type, int plen, void *ctxt)
1066 Authctxt *authctxt = ctxt;
1067 char *name, *inst, *lang, *prompt, *response;
1068 u_int num_prompts, i;
1071 debug2("input_userauth_info_req");
1073 if (authctxt == NULL)
1074 fatal("input_userauth_info_req: no authentication context");
1076 name = packet_get_string(NULL);
1077 inst = packet_get_string(NULL);
1078 lang = packet_get_string(NULL);
1079 if (strlen(name) > 0)
1081 if (strlen(inst) > 0)
1087 num_prompts = packet_get_int();
1089 * Begin to build info response packet based on prompts requested.
1090 * We commit to providing the correct number of responses, so if
1091 * further on we run into a problem that prevents this, we have to
1092 * be sure and clean this up and send a correct error response.
1094 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1095 packet_put_int(num_prompts);
1097 for (i = 0; i < num_prompts; i++) {
1098 prompt = packet_get_string(NULL);
1099 echo = packet_get_char();
1101 response = cli_prompt(prompt, echo);
1103 packet_put_cstring(response);
1104 memset(response, 0, strlen(response));
1108 packet_done(); /* done with parsing incoming message. */
1110 packet_inject_ignore(64);
1114 /* find auth method */
1117 * given auth method name, if configurable options permit this method fill
1118 * in auth_ident field and return true, otherwise return false.
1121 authmethod_is_enabled(Authmethod *method)
1125 /* return false if options indicate this method is disabled */
1126 if (method->enabled == NULL || *method->enabled == 0)
1128 /* return false if batch mode is enabled but method needs interactive mode */
1129 if (method->batch_flag != NULL && *method->batch_flag != 0)
1135 authmethod_lookup(const char *name)
1137 Authmethod *method = NULL;
1139 for (method = authmethods; method->name != NULL; method++)
1140 if (strcmp(name, method->name) == 0)
1142 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1146 /* XXX internal state */
1147 static Authmethod *current = NULL;
1148 static char *supported = NULL;
1149 static char *preferred = NULL;
1151 * Given the authentication method list sent by the server, return the
1152 * next method we should try. If the server initially sends a nil list,
1153 * use a built-in default list.
1156 authmethod_get(char *authlist)
1162 /* Use a suitable default if we're passed a nil list. */
1163 if (authlist == NULL || strlen(authlist) == 0)
1164 authlist = options.preferred_authentications;
1166 if (supported == NULL || strcmp(authlist, supported) != 0) {
1167 debug3("start over, passed a different list %s", authlist);
1168 if (supported != NULL)
1170 supported = xstrdup(authlist);
1171 preferred = options.preferred_authentications;
1172 debug3("preferred %s", preferred);
1174 } else if (current != NULL && authmethod_is_enabled(current))
1178 if ((name = match_list(preferred, supported, &next)) == NULL) {
1179 debug("no more auth methods to try");
1184 debug3("authmethod_lookup %s", name);
1185 debug3("remaining preferred: %s", preferred);
1186 if ((current = authmethod_lookup(name)) != NULL &&
1187 authmethod_is_enabled(current)) {
1188 debug3("authmethod_is_enabled %s", name);
1189 debug("next auth method to try is %s", name);
1198 authmethods_get(void)
1200 Authmethod *method = NULL;
1204 for (method = authmethods; method->name != NULL; method++) {
1205 if (authmethod_is_enabled(method)) {
1207 strlcat(buf, DELIM, sizeof buf);
1208 strlcat(buf, method->name, sizeof buf);
1211 return xstrdup(buf);