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 1.135 2004/03/05 10:53:58 markus Exp $");
28 #include "openbsd-compat/sys-queue.h"
39 #include "myproposal.h"
40 #include "sshconnect.h"
51 #include "pathnames.h"
58 extern char *client_version_string;
59 extern char *server_version_string;
60 extern Options options;
66 u_char *session_id2 = NULL;
67 u_int session_id2_len = 0;
70 struct sockaddr *xxx_hostaddr;
75 verify_host_key_callback(Key *hostkey)
77 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
78 fatal("Host key verification failed.");
83 ssh_kex2(char *host, struct sockaddr *hostaddr)
88 xxx_hostaddr = hostaddr;
90 if (options.ciphers == (char *)-1) {
91 logit("No valid ciphers for protocol version 2 given, using defaults.");
92 options.ciphers = NULL;
94 if (options.ciphers != NULL) {
95 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
96 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
98 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
99 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
100 myproposal[PROPOSAL_ENC_ALGS_STOC] =
101 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
102 if (options.compression) {
103 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
104 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib,none";
106 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
107 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib";
109 if (options.macs != NULL) {
110 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
111 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
113 if (options.hostkeyalgorithms != NULL)
114 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
115 options.hostkeyalgorithms;
117 if (options.rekey_limit)
118 packet_set_rekey_limit(options.rekey_limit);
120 /* start key exchange */
121 kex = kex_setup(myproposal);
122 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
123 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
124 kex->client_version_string=client_version_string;
125 kex->server_version_string=server_version_string;
126 kex->verify_host_key=&verify_host_key_callback;
130 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
132 session_id2 = kex->session_id;
133 session_id2_len = kex->session_id_len;
136 /* send 1st encrypted/maced/compressed message */
137 packet_start(SSH2_MSG_IGNORE);
138 packet_put_cstring("markus");
148 typedef struct Authctxt Authctxt;
149 typedef struct Authmethod Authmethod;
150 typedef struct identity Identity;
151 typedef struct idlist Idlist;
154 TAILQ_ENTRY(identity) next;
155 AuthenticationConnection *ac; /* set if agent supports key */
156 Key *key; /* public/private key */
157 char *filename; /* comment for agent-only keys */
159 int isprivate; /* key points to the private key */
161 TAILQ_HEAD(idlist, identity);
164 const char *server_user;
165 const char *local_user;
173 AuthenticationConnection *agent;
175 Sensitive *sensitive;
176 /* kbd-interactive */
182 char *name; /* string to compare against server's list */
183 int (*userauth)(Authctxt *authctxt);
184 int *enabled; /* flag in option struct that enables method */
185 int *batch_flag; /* flag in option struct that disables method */
188 void input_userauth_success(int, u_int32_t, void *);
189 void input_userauth_failure(int, u_int32_t, void *);
190 void input_userauth_banner(int, u_int32_t, void *);
191 void input_userauth_error(int, u_int32_t, void *);
192 void input_userauth_info_req(int, u_int32_t, void *);
193 void input_userauth_pk_ok(int, u_int32_t, void *);
194 void input_userauth_passwd_changereq(int, u_int32_t, void *);
196 int userauth_none(Authctxt *);
197 int userauth_pubkey(Authctxt *);
198 int userauth_passwd(Authctxt *);
199 int userauth_kbdint(Authctxt *);
200 int userauth_hostbased(Authctxt *);
201 int userauth_kerberos(Authctxt *);
204 int userauth_gssapi(Authctxt *authctxt);
205 void input_gssapi_response(int type, u_int32_t, void *);
206 void input_gssapi_token(int type, u_int32_t, void *);
207 void input_gssapi_hash(int type, u_int32_t, void *);
208 void input_gssapi_error(int, u_int32_t, void *);
209 void input_gssapi_errtok(int, u_int32_t, void *);
212 void userauth(Authctxt *, char *);
214 static int sign_and_send_pubkey(Authctxt *, Identity *);
215 static void pubkey_prepare(Authctxt *);
216 static void pubkey_cleanup(Authctxt *);
217 static Key *load_identity_file(char *);
219 static Authmethod *authmethod_get(char *authlist);
220 static Authmethod *authmethod_lookup(const char *name);
221 static char *authmethods_get(void);
223 Authmethod authmethods[] = {
227 &options.gss_authentication,
232 &options.hostbased_authentication,
236 &options.pubkey_authentication,
238 {"keyboard-interactive",
240 &options.kbd_interactive_authentication,
241 &options.batch_mode},
244 &options.password_authentication,
245 &options.batch_mode},
250 {NULL, NULL, NULL, NULL}
254 ssh_userauth2(const char *local_user, const char *server_user, char *host,
255 Sensitive *sensitive)
260 if (options.challenge_response_authentication)
261 options.kbd_interactive_authentication = 1;
263 packet_start(SSH2_MSG_SERVICE_REQUEST);
264 packet_put_cstring("ssh-userauth");
266 debug("SSH2_MSG_SERVICE_REQUEST sent");
268 type = packet_read();
269 if (type != SSH2_MSG_SERVICE_ACCEPT)
270 fatal("Server denied authentication request: %d", type);
271 if (packet_remaining() > 0) {
272 char *reply = packet_get_string(NULL);
273 debug2("service_accept: %s", reply);
276 debug2("buggy server: service_accept w/o service");
279 debug("SSH2_MSG_SERVICE_ACCEPT received");
281 if (options.preferred_authentications == NULL)
282 options.preferred_authentications = authmethods_get();
284 /* setup authentication context */
285 memset(&authctxt, 0, sizeof(authctxt));
286 pubkey_prepare(&authctxt);
287 authctxt.server_user = server_user;
288 authctxt.local_user = local_user;
289 authctxt.host = host;
290 authctxt.service = "ssh-connection"; /* service name */
291 authctxt.success = 0;
292 authctxt.method = authmethod_lookup("none");
293 authctxt.authlist = NULL;
294 authctxt.methoddata = NULL;
295 authctxt.sensitive = sensitive;
296 authctxt.info_req_seen = 0;
297 if (authctxt.method == NULL)
298 fatal("ssh_userauth2: internal error: cannot send userauth none request");
300 /* initial userauth request */
301 userauth_none(&authctxt);
303 dispatch_init(&input_userauth_error);
304 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
305 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
306 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
307 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
309 pubkey_cleanup(&authctxt);
310 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
312 debug("Authentication succeeded (%s).", authctxt.method->name);
316 userauth(Authctxt *authctxt, char *authlist)
318 if (authctxt->methoddata) {
319 xfree(authctxt->methoddata);
320 authctxt->methoddata = NULL;
322 if (authlist == NULL) {
323 authlist = authctxt->authlist;
325 if (authctxt->authlist)
326 xfree(authctxt->authlist);
327 authctxt->authlist = authlist;
330 Authmethod *method = authmethod_get(authlist);
332 fatal("Permission denied (%s).", authlist);
333 authctxt->method = method;
335 /* reset the per method handler */
336 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
337 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
339 /* and try new method */
340 if (method->userauth(authctxt) != 0) {
341 debug2("we sent a %s packet, wait for reply", method->name);
344 debug2("we did not send a packet, disable method");
345 method->enabled = NULL;
351 input_userauth_error(int type, u_int32_t seq, void *ctxt)
353 fatal("input_userauth_error: bad message during authentication: "
358 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
362 debug3("input_userauth_banner");
363 msg = packet_get_string(NULL);
364 lang = packet_get_string(NULL);
365 if (options.log_level > SYSLOG_LEVEL_QUIET)
366 fprintf(stderr, "%s", msg);
372 input_userauth_success(int type, u_int32_t seq, void *ctxt)
374 Authctxt *authctxt = ctxt;
375 if (authctxt == NULL)
376 fatal("input_userauth_success: no authentication context");
377 if (authctxt->authlist) {
378 xfree(authctxt->authlist);
379 authctxt->authlist = NULL;
381 if (authctxt->methoddata) {
382 xfree(authctxt->methoddata);
383 authctxt->methoddata = NULL;
385 authctxt->success = 1; /* break out */
389 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
391 Authctxt *authctxt = ctxt;
392 char *authlist = NULL;
395 if (authctxt == NULL)
396 fatal("input_userauth_failure: no authentication context");
398 authlist = packet_get_string(NULL);
399 partial = packet_get_char();
403 logit("Authenticated with partial success.");
404 debug("Authentications that can continue: %s", authlist);
406 userauth(authctxt, authlist);
409 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
411 Authctxt *authctxt = ctxt;
415 int pktype, sent = 0;
420 if (authctxt == NULL)
421 fatal("input_userauth_pk_ok: no authentication context");
422 if (datafellows & SSH_BUG_PKOK) {
423 /* this is similar to SSH_BUG_PKAUTH */
424 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
425 pkblob = packet_get_string(&blen);
427 buffer_append(&b, pkblob, blen);
428 pkalg = buffer_get_string(&b, &alen);
431 pkalg = packet_get_string(&alen);
432 pkblob = packet_get_string(&blen);
436 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
438 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
439 debug("unknown pkalg %s", pkalg);
442 if ((key = key_from_blob(pkblob, blen)) == NULL) {
443 debug("no key from blob. pkalg %s", pkalg);
446 if (key->type != pktype) {
447 error("input_userauth_pk_ok: type mismatch "
448 "for decoded key (received %d, expected %d)",
452 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
453 debug2("input_userauth_pk_ok: fp %s", fp);
457 * search keys in the reverse order, because last candidate has been
458 * moved to the end of the queue. this also avoids confusion by
461 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, next, idlist) {
462 if (key_equal(key, id->key)) {
463 sent = sign_and_send_pubkey(authctxt, id);
473 /* try another method if we did not send a packet */
475 userauth(authctxt, NULL);
480 userauth_gssapi(Authctxt *authctxt)
482 Gssctxt *gssctxt = NULL;
483 static gss_OID_set gss_supported = NULL;
488 /* Try one GSSAPI method at a time, rather than sending them all at
491 if (gss_supported == NULL)
492 gss_indicate_mechs(&min, &gss_supported);
494 /* Check to see if the mechanism is usable before we offer it */
495 while (mech < gss_supported->count && !ok) {
497 ssh_gssapi_delete_ctx(&gssctxt);
498 ssh_gssapi_build_ctx(&gssctxt);
499 ssh_gssapi_set_oid(gssctxt, &gss_supported->elements[mech]);
501 /* My DER encoding requires length<128 */
502 if (gss_supported->elements[mech].length < 128 &&
503 !GSS_ERROR(ssh_gssapi_import_name(gssctxt,
505 ok = 1; /* Mechanism works */
513 authctxt->methoddata=(void *)gssctxt;
515 packet_start(SSH2_MSG_USERAUTH_REQUEST);
516 packet_put_cstring(authctxt->server_user);
517 packet_put_cstring(authctxt->service);
518 packet_put_cstring(authctxt->method->name);
522 packet_put_int((gss_supported->elements[mech].length) + 2);
523 packet_put_char(SSH_GSS_OIDTYPE);
524 packet_put_char(gss_supported->elements[mech].length);
525 packet_put_raw(gss_supported->elements[mech].elements,
526 gss_supported->elements[mech].length);
530 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
531 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
532 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
533 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
535 mech++; /* Move along to next candidate */
541 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
543 Authctxt *authctxt = ctxt;
544 Gssctxt *gssctxt = authctxt->methoddata;
545 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
546 gss_buffer_desc gssbuf, mic;
547 OM_uint32 status, ms, flags;
550 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
551 recv_tok, &send_tok, &flags);
553 if (send_tok.length > 0) {
554 if (GSS_ERROR(status))
555 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
557 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
559 packet_put_string(send_tok.value, send_tok.length);
561 gss_release_buffer(&ms, &send_tok);
564 if (status == GSS_S_COMPLETE) {
565 /* send either complete or MIC, depending on mechanism */
566 if (!(flags & GSS_C_INTEG_FLAG)) {
567 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
570 ssh_gssapi_buildmic(&b, authctxt->server_user,
571 authctxt->service, "gssapi-with-mic");
573 gssbuf.value = buffer_ptr(&b);
574 gssbuf.length = buffer_len(&b);
576 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
578 if (!GSS_ERROR(status)) {
579 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
580 packet_put_string(mic.value, mic.length);
586 gss_release_buffer(&ms, &mic);
594 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
596 Authctxt *authctxt = ctxt;
601 if (authctxt == NULL)
602 fatal("input_gssapi_response: no authentication context");
603 gssctxt = authctxt->methoddata;
606 oidv = packet_get_string(&oidlen);
609 oidv[0] != SSH_GSS_OIDTYPE ||
610 oidv[1] != oidlen - 2) {
612 debug("Badly encoded mechanism OID received");
613 userauth(authctxt, NULL);
617 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
618 fatal("Server returned different OID than expected");
624 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
625 /* Start again with next method on list */
626 debug("Trying to start again");
627 userauth(authctxt, NULL);
633 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
635 Authctxt *authctxt = ctxt;
636 gss_buffer_desc recv_tok;
640 if (authctxt == NULL)
641 fatal("input_gssapi_response: no authentication context");
643 recv_tok.value = packet_get_string(&slen);
644 recv_tok.length = slen; /* safe typecast */
648 status = process_gssapi_token(ctxt, &recv_tok);
650 xfree(recv_tok.value);
652 if (GSS_ERROR(status)) {
653 /* Start again with the next method in the list */
654 userauth(authctxt, NULL);
660 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
662 Authctxt *authctxt = ctxt;
664 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
665 gss_buffer_desc recv_tok;
666 OM_uint32 status, ms;
669 if (authctxt == NULL)
670 fatal("input_gssapi_response: no authentication context");
671 gssctxt = authctxt->methoddata;
673 recv_tok.value = packet_get_string(&len);
674 recv_tok.length = len;
678 /* Stick it into GSSAPI and see what it says */
679 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
680 &recv_tok, &send_tok, NULL);
682 xfree(recv_tok.value);
683 gss_release_buffer(&ms, &send_tok);
685 /* Server will be returning a failed packet after this one */
689 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
695 maj=packet_get_int();
696 min=packet_get_int();
697 msg=packet_get_string(NULL);
698 lang=packet_get_string(NULL);
702 debug("Server GSSAPI Error:\n%s\n", msg);
709 userauth_none(Authctxt *authctxt)
711 /* initial userauth request */
712 packet_start(SSH2_MSG_USERAUTH_REQUEST);
713 packet_put_cstring(authctxt->server_user);
714 packet_put_cstring(authctxt->service);
715 packet_put_cstring(authctxt->method->name);
721 userauth_passwd(Authctxt *authctxt)
723 static int attempt = 0;
727 if (attempt++ >= options.number_of_password_prompts)
731 error("Permission denied, please try again.");
733 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
734 authctxt->server_user, authctxt->host);
735 password = read_passphrase(prompt, 0);
736 packet_start(SSH2_MSG_USERAUTH_REQUEST);
737 packet_put_cstring(authctxt->server_user);
738 packet_put_cstring(authctxt->service);
739 packet_put_cstring(authctxt->method->name);
741 packet_put_cstring(password);
742 memset(password, 0, strlen(password));
744 packet_add_padding(64);
747 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
748 &input_userauth_passwd_changereq);
753 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
756 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
758 Authctxt *authctxt = ctxt;
759 char *info, *lang, *password = NULL, *retype = NULL;
762 debug2("input_userauth_passwd_changereq");
764 if (authctxt == NULL)
765 fatal("input_userauth_passwd_changereq: "
766 "no authentication context");
768 info = packet_get_string(NULL);
769 lang = packet_get_string(NULL);
770 if (strlen(info) > 0)
774 packet_start(SSH2_MSG_USERAUTH_REQUEST);
775 packet_put_cstring(authctxt->server_user);
776 packet_put_cstring(authctxt->service);
777 packet_put_cstring(authctxt->method->name);
778 packet_put_char(1); /* additional info */
779 snprintf(prompt, sizeof(prompt),
780 "Enter %.30s@%.128s's old password: ",
781 authctxt->server_user, authctxt->host);
782 password = read_passphrase(prompt, 0);
783 packet_put_cstring(password);
784 memset(password, 0, strlen(password));
787 while (password == NULL) {
788 snprintf(prompt, sizeof(prompt),
789 "Enter %.30s@%.128s's new password: ",
790 authctxt->server_user, authctxt->host);
791 password = read_passphrase(prompt, RP_ALLOW_EOF);
792 if (password == NULL) {
796 snprintf(prompt, sizeof(prompt),
797 "Retype %.30s@%.128s's new password: ",
798 authctxt->server_user, authctxt->host);
799 retype = read_passphrase(prompt, 0);
800 if (strcmp(password, retype) != 0) {
801 memset(password, 0, strlen(password));
803 logit("Mismatch; try again, EOF to quit.");
806 memset(retype, 0, strlen(retype));
809 packet_put_cstring(password);
810 memset(password, 0, strlen(password));
812 packet_add_padding(64);
815 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
816 &input_userauth_passwd_changereq);
820 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
821 u_char *data, u_int datalen)
826 /* the agent supports this key */
828 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
831 * we have already loaded the private key or
832 * the private key is stored in external hardware
834 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
835 return (key_sign(id->key, sigp, lenp, data, datalen));
836 /* load the private key from the file */
837 if ((prv = load_identity_file(id->filename)) == NULL)
839 ret = key_sign(prv, sigp, lenp, data, datalen);
845 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
848 u_char *blob, *signature;
854 debug3("sign_and_send_pubkey");
856 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
857 /* we cannot handle this key */
858 debug3("sign_and_send_pubkey: cannot handle key");
861 /* data to be signed */
863 if (datafellows & SSH_OLD_SESSIONID) {
864 buffer_append(&b, session_id2, session_id2_len);
865 skip = session_id2_len;
867 buffer_put_string(&b, session_id2, session_id2_len);
868 skip = buffer_len(&b);
870 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
871 buffer_put_cstring(&b, authctxt->server_user);
872 buffer_put_cstring(&b,
873 datafellows & SSH_BUG_PKSERVICE ?
876 if (datafellows & SSH_BUG_PKAUTH) {
877 buffer_put_char(&b, have_sig);
879 buffer_put_cstring(&b, authctxt->method->name);
880 buffer_put_char(&b, have_sig);
881 buffer_put_cstring(&b, key_ssh_name(id->key));
883 buffer_put_string(&b, blob, bloblen);
885 /* generate signature */
886 ret = identity_sign(id, &signature, &slen,
887 buffer_ptr(&b), buffer_len(&b));
896 if (datafellows & SSH_BUG_PKSERVICE) {
898 buffer_append(&b, session_id2, session_id2_len);
899 skip = session_id2_len;
900 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
901 buffer_put_cstring(&b, authctxt->server_user);
902 buffer_put_cstring(&b, authctxt->service);
903 buffer_put_cstring(&b, authctxt->method->name);
904 buffer_put_char(&b, have_sig);
905 if (!(datafellows & SSH_BUG_PKAUTH))
906 buffer_put_cstring(&b, key_ssh_name(id->key));
907 buffer_put_string(&b, blob, bloblen);
911 /* append signature */
912 buffer_put_string(&b, signature, slen);
915 /* skip session id and packet type */
916 if (buffer_len(&b) < skip + 1)
917 fatal("userauth_pubkey: internal error");
918 buffer_consume(&b, skip + 1);
920 /* put remaining data from buffer into packet */
921 packet_start(SSH2_MSG_USERAUTH_REQUEST);
922 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
930 send_pubkey_test(Authctxt *authctxt, Identity *id)
933 u_int bloblen, have_sig = 0;
935 debug3("send_pubkey_test");
937 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
938 /* we cannot handle this key */
939 debug3("send_pubkey_test: cannot handle key");
942 /* register callback for USERAUTH_PK_OK message */
943 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
945 packet_start(SSH2_MSG_USERAUTH_REQUEST);
946 packet_put_cstring(authctxt->server_user);
947 packet_put_cstring(authctxt->service);
948 packet_put_cstring(authctxt->method->name);
949 packet_put_char(have_sig);
950 if (!(datafellows & SSH_BUG_PKAUTH))
951 packet_put_cstring(key_ssh_name(id->key));
952 packet_put_string(blob, bloblen);
959 load_identity_file(char *filename)
962 char prompt[300], *passphrase;
966 if (stat(filename, &st) < 0) {
967 debug3("no such identity: %s", filename);
970 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
971 if (private == NULL) {
972 if (options.batch_mode)
974 snprintf(prompt, sizeof prompt,
975 "Enter passphrase for key '%.100s': ", filename);
976 for (i = 0; i < options.number_of_password_prompts; i++) {
977 passphrase = read_passphrase(prompt, 0);
978 if (strcmp(passphrase, "") != 0) {
979 private = key_load_private_type(KEY_UNSPEC, filename,
983 debug2("no passphrase given, try next key");
986 memset(passphrase, 0, strlen(passphrase));
988 if (private != NULL || quit)
990 debug2("bad passphrase given, try again...");
997 * try keys in the following order:
998 * 1. agent keys that are found in the config file
999 * 2. other agent keys
1000 * 3. keys that are only listed in the config file
1003 pubkey_prepare(Authctxt *authctxt)
1006 Idlist agent, files, *preferred;
1008 AuthenticationConnection *ac;
1012 TAILQ_INIT(&agent); /* keys from the agent */
1013 TAILQ_INIT(&files); /* keys from the config file */
1014 preferred = &authctxt->keys;
1015 TAILQ_INIT(preferred); /* preferred order of keys */
1017 /* list of keys stored in the filesystem */
1018 for (i = 0; i < options.num_identity_files; i++) {
1019 key = options.identity_keys[i];
1020 if (key && key->type == KEY_RSA1)
1022 options.identity_keys[i] = NULL;
1023 id = xmalloc(sizeof(*id));
1024 memset(id, 0, sizeof(*id));
1026 id->filename = xstrdup(options.identity_files[i]);
1027 TAILQ_INSERT_TAIL(&files, id, next);
1029 /* list of keys supported by the agent */
1030 if ((ac = ssh_get_authentication_connection())) {
1031 for (key = ssh_get_first_identity(ac, &comment, 2);
1033 key = ssh_get_next_identity(ac, &comment, 2)) {
1035 TAILQ_FOREACH(id, &files, next) {
1036 /* agent keys from the config file are preferred */
1037 if (key_equal(key, id->key)) {
1040 TAILQ_REMOVE(&files, id, next);
1041 TAILQ_INSERT_TAIL(preferred, id, next);
1047 if (!found && !options.identities_only) {
1048 id = xmalloc(sizeof(*id));
1049 memset(id, 0, sizeof(*id));
1051 id->filename = comment;
1053 TAILQ_INSERT_TAIL(&agent, id, next);
1056 /* append remaining agent keys */
1057 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1058 TAILQ_REMOVE(&agent, id, next);
1059 TAILQ_INSERT_TAIL(preferred, id, next);
1061 authctxt->agent = ac;
1063 /* append remaining keys from the config file */
1064 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1065 TAILQ_REMOVE(&files, id, next);
1066 TAILQ_INSERT_TAIL(preferred, id, next);
1068 TAILQ_FOREACH(id, preferred, next) {
1069 debug2("key: %s (%p)", id->filename, id->key);
1074 pubkey_cleanup(Authctxt *authctxt)
1078 if (authctxt->agent != NULL)
1079 ssh_close_authentication_connection(authctxt->agent);
1080 for (id = TAILQ_FIRST(&authctxt->keys); id;
1081 id = TAILQ_FIRST(&authctxt->keys)) {
1082 TAILQ_REMOVE(&authctxt->keys, id, next);
1086 xfree(id->filename);
1092 userauth_pubkey(Authctxt *authctxt)
1097 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1100 /* move key to the end of the queue */
1101 TAILQ_REMOVE(&authctxt->keys, id, next);
1102 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1104 * send a test message if we have the public key. for
1105 * encrypted keys we cannot do this and have to load the
1106 * private key instead
1108 if (id->key && id->key->type != KEY_RSA1) {
1109 debug("Offering public key: %s", id->filename);
1110 sent = send_pubkey_test(authctxt, id);
1111 } else if (id->key == NULL) {
1112 debug("Trying private key: %s", id->filename);
1113 id->key = load_identity_file(id->filename);
1114 if (id->key != NULL) {
1116 sent = sign_and_send_pubkey(authctxt, id);
1128 * Send userauth request message specifying keyboard-interactive method.
1131 userauth_kbdint(Authctxt *authctxt)
1133 static int attempt = 0;
1135 if (attempt++ >= options.number_of_password_prompts)
1137 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1138 if (attempt > 1 && !authctxt->info_req_seen) {
1139 debug3("userauth_kbdint: disable: no info_req_seen");
1140 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1144 debug2("userauth_kbdint");
1145 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1146 packet_put_cstring(authctxt->server_user);
1147 packet_put_cstring(authctxt->service);
1148 packet_put_cstring(authctxt->method->name);
1149 packet_put_cstring(""); /* lang */
1150 packet_put_cstring(options.kbd_interactive_devices ?
1151 options.kbd_interactive_devices : "");
1154 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1159 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1162 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1164 Authctxt *authctxt = ctxt;
1165 char *name, *inst, *lang, *prompt, *response;
1166 u_int num_prompts, i;
1169 debug2("input_userauth_info_req");
1171 if (authctxt == NULL)
1172 fatal("input_userauth_info_req: no authentication context");
1174 authctxt->info_req_seen = 1;
1176 name = packet_get_string(NULL);
1177 inst = packet_get_string(NULL);
1178 lang = packet_get_string(NULL);
1179 if (strlen(name) > 0)
1181 if (strlen(inst) > 0)
1187 num_prompts = packet_get_int();
1189 * Begin to build info response packet based on prompts requested.
1190 * We commit to providing the correct number of responses, so if
1191 * further on we run into a problem that prevents this, we have to
1192 * be sure and clean this up and send a correct error response.
1194 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1195 packet_put_int(num_prompts);
1197 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1198 for (i = 0; i < num_prompts; i++) {
1199 prompt = packet_get_string(NULL);
1200 echo = packet_get_char();
1202 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1204 packet_put_cstring(response);
1205 memset(response, 0, strlen(response));
1209 packet_check_eom(); /* done with parsing incoming message. */
1211 packet_add_padding(64);
1216 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1217 u_char *data, u_int datalen)
1222 int to[2], from[2], status, version = 2;
1224 debug2("ssh_keysign called");
1226 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1227 error("ssh_keysign: no installed: %s", strerror(errno));
1230 if (fflush(stdout) != 0)
1231 error("ssh_keysign: fflush: %s", strerror(errno));
1233 error("ssh_keysign: pipe: %s", strerror(errno));
1236 if (pipe(from) < 0) {
1237 error("ssh_keysign: pipe: %s", strerror(errno));
1240 if ((pid = fork()) < 0) {
1241 error("ssh_keysign: fork: %s", strerror(errno));
1248 if (dup2(from[1], STDOUT_FILENO) < 0)
1249 fatal("ssh_keysign: dup2: %s", strerror(errno));
1251 if (dup2(to[0], STDIN_FILENO) < 0)
1252 fatal("ssh_keysign: dup2: %s", strerror(errno));
1255 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1256 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1263 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1264 buffer_put_string(&b, data, datalen);
1265 if (ssh_msg_send(to[1], version, &b) == -1)
1266 fatal("ssh_keysign: couldn't send request");
1268 if (ssh_msg_recv(from[0], &b) < 0) {
1269 error("ssh_keysign: no reply");
1276 while (waitpid(pid, &status, 0) < 0)
1280 if (buffer_get_char(&b) != version) {
1281 error("ssh_keysign: bad version");
1285 *sigp = buffer_get_string(&b, lenp);
1292 userauth_hostbased(Authctxt *authctxt)
1294 Key *private = NULL;
1295 Sensitive *sensitive = authctxt->sensitive;
1297 u_char *signature, *blob;
1298 char *chost, *pkalg, *p;
1299 const char *service;
1301 int ok, i, len, found = 0;
1303 /* check for a useful key */
1304 for (i = 0; i < sensitive->nkeys; i++) {
1305 private = sensitive->keys[i];
1306 if (private && private->type != KEY_RSA1) {
1308 /* we take and free the key */
1309 sensitive->keys[i] = NULL;
1314 debug("No more client hostkeys for hostbased authentication.");
1317 if (key_to_blob(private, &blob, &blen) == 0) {
1321 /* figure out a name for the client host */
1322 p = get_local_name(packet_get_connection_in());
1324 error("userauth_hostbased: cannot get local ipaddr/name");
1328 len = strlen(p) + 2;
1329 chost = xmalloc(len);
1330 strlcpy(chost, p, len);
1331 strlcat(chost, ".", len);
1332 debug2("userauth_hostbased: chost %s", chost);
1335 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1337 pkalg = xstrdup(key_ssh_name(private));
1339 /* construct data */
1340 buffer_put_string(&b, session_id2, session_id2_len);
1341 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1342 buffer_put_cstring(&b, authctxt->server_user);
1343 buffer_put_cstring(&b, service);
1344 buffer_put_cstring(&b, authctxt->method->name);
1345 buffer_put_cstring(&b, pkalg);
1346 buffer_put_string(&b, blob, blen);
1347 buffer_put_cstring(&b, chost);
1348 buffer_put_cstring(&b, authctxt->local_user);
1352 if (sensitive->external_keysign)
1353 ok = ssh_keysign(private, &signature, &slen,
1354 buffer_ptr(&b), buffer_len(&b));
1356 ok = key_sign(private, &signature, &slen,
1357 buffer_ptr(&b), buffer_len(&b));
1361 error("key_sign failed");
1366 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1367 packet_put_cstring(authctxt->server_user);
1368 packet_put_cstring(authctxt->service);
1369 packet_put_cstring(authctxt->method->name);
1370 packet_put_cstring(pkalg);
1371 packet_put_string(blob, blen);
1372 packet_put_cstring(chost);
1373 packet_put_cstring(authctxt->local_user);
1374 packet_put_string(signature, slen);
1375 memset(signature, 's', slen);
1384 /* find auth method */
1387 * given auth method name, if configurable options permit this method fill
1388 * in auth_ident field and return true, otherwise return false.
1391 authmethod_is_enabled(Authmethod *method)
1395 /* return false if options indicate this method is disabled */
1396 if (method->enabled == NULL || *method->enabled == 0)
1398 /* return false if batch mode is enabled but method needs interactive mode */
1399 if (method->batch_flag != NULL && *method->batch_flag != 0)
1405 authmethod_lookup(const char *name)
1407 Authmethod *method = NULL;
1409 for (method = authmethods; method->name != NULL; method++)
1410 if (strcmp(name, method->name) == 0)
1412 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1416 /* XXX internal state */
1417 static Authmethod *current = NULL;
1418 static char *supported = NULL;
1419 static char *preferred = NULL;
1422 * Given the authentication method list sent by the server, return the
1423 * next method we should try. If the server initially sends a nil list,
1424 * use a built-in default list.
1427 authmethod_get(char *authlist)
1432 /* Use a suitable default if we're passed a nil list. */
1433 if (authlist == NULL || strlen(authlist) == 0)
1434 authlist = options.preferred_authentications;
1436 if (supported == NULL || strcmp(authlist, supported) != 0) {
1437 debug3("start over, passed a different list %s", authlist);
1438 if (supported != NULL)
1440 supported = xstrdup(authlist);
1441 preferred = options.preferred_authentications;
1442 debug3("preferred %s", preferred);
1444 } else if (current != NULL && authmethod_is_enabled(current))
1448 if ((name = match_list(preferred, supported, &next)) == NULL) {
1449 debug("No more authentication methods to try.");
1454 debug3("authmethod_lookup %s", name);
1455 debug3("remaining preferred: %s", preferred);
1456 if ((current = authmethod_lookup(name)) != NULL &&
1457 authmethod_is_enabled(current)) {
1458 debug3("authmethod_is_enabled %s", name);
1459 debug("Next authentication method: %s", name);
1466 authmethods_get(void)
1468 Authmethod *method = NULL;
1473 for (method = authmethods; method->name != NULL; method++) {
1474 if (authmethod_is_enabled(method)) {
1475 if (buffer_len(&b) > 0)
1476 buffer_append(&b, ",", 1);
1477 buffer_append(&b, method->name, strlen(method->name));
1480 buffer_append(&b, "\0", 1);
1481 list = xstrdup(buffer_ptr(&b));