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 1.122 2003/08/22 13:20:03 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)
361 debug3("input_userauth_banner");
362 msg = packet_get_string(NULL);
363 lang = packet_get_string(NULL);
364 fprintf(stderr, "%s", msg);
370 input_userauth_success(int type, u_int32_t seq, void *ctxt)
372 Authctxt *authctxt = ctxt;
373 if (authctxt == NULL)
374 fatal("input_userauth_success: no authentication context");
375 if (authctxt->authlist)
376 xfree(authctxt->authlist);
377 if (authctxt->methoddata)
378 xfree(authctxt->methoddata);
379 authctxt->success = 1; /* break out */
383 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
385 Authctxt *authctxt = ctxt;
386 char *authlist = NULL;
389 if (authctxt == NULL)
390 fatal("input_userauth_failure: no authentication context");
392 authlist = packet_get_string(NULL);
393 partial = packet_get_char();
397 logit("Authenticated with partial success.");
398 debug("Authentications that can continue: %s", authlist);
400 userauth(authctxt, authlist);
403 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
405 Authctxt *authctxt = ctxt;
409 int pktype, sent = 0;
414 if (authctxt == NULL)
415 fatal("input_userauth_pk_ok: no authentication context");
416 if (datafellows & SSH_BUG_PKOK) {
417 /* this is similar to SSH_BUG_PKAUTH */
418 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
419 pkblob = packet_get_string(&blen);
421 buffer_append(&b, pkblob, blen);
422 pkalg = buffer_get_string(&b, &alen);
425 pkalg = packet_get_string(&alen);
426 pkblob = packet_get_string(&blen);
430 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
432 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
433 debug("unknown pkalg %s", pkalg);
436 if ((key = key_from_blob(pkblob, blen)) == NULL) {
437 debug("no key from blob. pkalg %s", pkalg);
440 if (key->type != pktype) {
441 error("input_userauth_pk_ok: type mismatch "
442 "for decoded key (received %d, expected %d)",
446 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
447 debug2("input_userauth_pk_ok: fp %s", fp);
450 TAILQ_FOREACH(id, &authctxt->keys, next) {
451 if (key_equal(key, id->key)) {
452 sent = sign_and_send_pubkey(authctxt, id);
462 /* try another method if we did not send a packet */
464 userauth(authctxt, NULL);
469 userauth_gssapi(Authctxt *authctxt)
471 Gssctxt *gssctxt = NULL;
472 static gss_OID_set supported = NULL;
477 /* Try one GSSAPI method at a time, rather than sending them all at
480 if (supported == NULL)
481 gss_indicate_mechs(&min, &supported);
483 /* Check to see if the mechanism is usable before we offer it */
484 while (mech<supported->count && !ok) {
486 ssh_gssapi_delete_ctx(&gssctxt);
487 ssh_gssapi_build_ctx(&gssctxt);
488 ssh_gssapi_set_oid(gssctxt, &supported->elements[mech]);
490 /* My DER encoding requires length<128 */
491 if (supported->elements[mech].length < 128 &&
492 !GSS_ERROR(ssh_gssapi_import_name(gssctxt,
494 ok = 1; /* Mechanism works */
502 authctxt->methoddata=(void *)gssctxt;
504 packet_start(SSH2_MSG_USERAUTH_REQUEST);
505 packet_put_cstring(authctxt->server_user);
506 packet_put_cstring(authctxt->service);
507 packet_put_cstring(authctxt->method->name);
511 /* Some servers encode the OID incorrectly (as we used to) */
512 if (datafellows & SSH_BUG_GSSAPI_BER) {
513 packet_put_string(supported->elements[mech].elements,
514 supported->elements[mech].length);
516 packet_put_int((supported->elements[mech].length)+2);
517 packet_put_char(SSH_GSS_OIDTYPE);
518 packet_put_char(supported->elements[mech].length);
519 packet_put_raw(supported->elements[mech].elements,
520 supported->elements[mech].length);
525 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
526 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
527 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
528 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
530 mech++; /* Move along to next candidate */
536 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
538 Authctxt *authctxt = ctxt;
540 OM_uint32 status, ms;
543 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
545 if (authctxt == NULL)
546 fatal("input_gssapi_response: no authentication context");
547 gssctxt = authctxt->methoddata;
550 oidv = packet_get_string(&oidlen);
552 if (datafellows & SSH_BUG_GSSAPI_BER) {
553 if (!ssh_gssapi_check_oid(gssctxt, oidv, oidlen))
554 fatal("Server returned different OID than expected");
556 if(oidv[0] != SSH_GSS_OIDTYPE || oidv[1] != oidlen-2) {
557 debug("Badly encoded mechanism OID received");
558 userauth(authctxt, NULL);
562 if (!ssh_gssapi_check_oid(gssctxt, oidv+2, oidlen-2))
563 fatal("Server returned different OID than expected");
570 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
571 GSS_C_NO_BUFFER, &send_tok, NULL);
572 if (GSS_ERROR(status)) {
573 if (send_tok.length > 0) {
574 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
575 packet_put_string(send_tok.value, send_tok.length);
577 gss_release_buffer(&ms, &send_tok);
579 /* Start again with next method on list */
580 debug("Trying to start again");
581 userauth(authctxt, NULL);
585 /* We must have data to send */
586 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
587 packet_put_string(send_tok.value, send_tok.length);
589 gss_release_buffer(&ms, &send_tok);
593 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
595 Authctxt *authctxt = ctxt;
597 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
598 gss_buffer_desc recv_tok;
599 OM_uint32 status, ms;
602 if (authctxt == NULL)
603 fatal("input_gssapi_response: no authentication context");
604 gssctxt = authctxt->methoddata;
606 recv_tok.value = packet_get_string(&slen);
607 recv_tok.length = slen; /* safe typecast */
611 status=ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
612 &recv_tok, &send_tok, NULL);
614 xfree(recv_tok.value);
616 if (GSS_ERROR(status)) {
617 if (send_tok.length > 0) {
618 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
619 packet_put_string(send_tok.value, send_tok.length);
621 gss_release_buffer(&ms, &send_tok);
623 /* Start again with the next method in the list */
624 userauth(authctxt, NULL);
628 if (send_tok.length > 0) {
629 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
630 packet_put_string(send_tok.value, send_tok.length);
632 gss_release_buffer(&ms, &send_tok);
635 if (status == GSS_S_COMPLETE) {
636 /* If that succeeded, send a exchange complete message */
637 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
643 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
645 Authctxt *authctxt = ctxt;
647 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
648 gss_buffer_desc recv_tok;
649 OM_uint32 status, ms;
651 if (authctxt == NULL)
652 fatal("input_gssapi_response: no authentication context");
653 gssctxt = authctxt->methoddata;
655 recv_tok.value = packet_get_string(&recv_tok.length);
659 /* Stick it into GSSAPI and see what it says */
660 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
661 &recv_tok, &send_tok, NULL);
663 xfree(recv_tok.value);
664 gss_release_buffer(&ms, &send_tok);
666 /* Server will be returning a failed packet after this one */
670 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
676 maj=packet_get_int();
677 min=packet_get_int();
678 msg=packet_get_string(NULL);
679 lang=packet_get_string(NULL);
683 debug("Server GSSAPI Error:\n%s\n", msg);
690 userauth_none(Authctxt *authctxt)
692 /* initial userauth request */
693 packet_start(SSH2_MSG_USERAUTH_REQUEST);
694 packet_put_cstring(authctxt->server_user);
695 packet_put_cstring(authctxt->service);
696 packet_put_cstring(authctxt->method->name);
702 userauth_passwd(Authctxt *authctxt)
704 static int attempt = 0;
708 if (attempt++ >= options.number_of_password_prompts)
712 error("Permission denied, please try again.");
714 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
715 authctxt->server_user, authctxt->host);
716 password = read_passphrase(prompt, 0);
717 packet_start(SSH2_MSG_USERAUTH_REQUEST);
718 packet_put_cstring(authctxt->server_user);
719 packet_put_cstring(authctxt->service);
720 packet_put_cstring(authctxt->method->name);
722 packet_put_cstring(password);
723 memset(password, 0, strlen(password));
725 packet_add_padding(64);
728 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
729 &input_userauth_passwd_changereq);
734 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
737 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
739 Authctxt *authctxt = ctxt;
740 char *info, *lang, *password = NULL, *retype = NULL;
743 debug2("input_userauth_passwd_changereq");
745 if (authctxt == NULL)
746 fatal("input_userauth_passwd_changereq: "
747 "no authentication context");
749 info = packet_get_string(NULL);
750 lang = packet_get_string(NULL);
751 if (strlen(info) > 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);
759 packet_put_char(1); /* additional info */
760 snprintf(prompt, sizeof(prompt),
761 "Enter %.30s@%.128s's old password: ",
762 authctxt->server_user, authctxt->host);
763 password = read_passphrase(prompt, 0);
764 packet_put_cstring(password);
765 memset(password, 0, strlen(password));
768 while (password == NULL) {
769 snprintf(prompt, sizeof(prompt),
770 "Enter %.30s@%.128s's new password: ",
771 authctxt->server_user, authctxt->host);
772 password = read_passphrase(prompt, RP_ALLOW_EOF);
773 if (password == NULL) {
777 snprintf(prompt, sizeof(prompt),
778 "Retype %.30s@%.128s's new password: ",
779 authctxt->server_user, authctxt->host);
780 retype = read_passphrase(prompt, 0);
781 if (strcmp(password, retype) != 0) {
782 memset(password, 0, strlen(password));
784 logit("Mismatch; try again, EOF to quit.");
787 memset(retype, 0, strlen(retype));
790 packet_put_cstring(password);
791 memset(password, 0, strlen(password));
793 packet_add_padding(64);
796 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
797 &input_userauth_passwd_changereq);
801 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
802 u_char *data, u_int datalen)
807 /* the agent supports this key */
809 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
812 * we have already loaded the private key or
813 * the private key is stored in external hardware
815 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
816 return (key_sign(id->key, sigp, lenp, data, datalen));
817 /* load the private key from the file */
818 if ((prv = load_identity_file(id->filename)) == NULL)
820 ret = key_sign(prv, sigp, lenp, data, datalen);
826 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
829 u_char *blob, *signature;
835 debug3("sign_and_send_pubkey");
837 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
838 /* we cannot handle this key */
839 debug3("sign_and_send_pubkey: cannot handle key");
842 /* data to be signed */
844 if (datafellows & SSH_OLD_SESSIONID) {
845 buffer_append(&b, session_id2, session_id2_len);
846 skip = session_id2_len;
848 buffer_put_string(&b, session_id2, session_id2_len);
849 skip = buffer_len(&b);
851 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
852 buffer_put_cstring(&b, authctxt->server_user);
853 buffer_put_cstring(&b,
854 datafellows & SSH_BUG_PKSERVICE ?
857 if (datafellows & SSH_BUG_PKAUTH) {
858 buffer_put_char(&b, have_sig);
860 buffer_put_cstring(&b, authctxt->method->name);
861 buffer_put_char(&b, have_sig);
862 buffer_put_cstring(&b, key_ssh_name(id->key));
864 buffer_put_string(&b, blob, bloblen);
866 /* generate signature */
867 ret = identity_sign(id, &signature, &slen,
868 buffer_ptr(&b), buffer_len(&b));
877 if (datafellows & SSH_BUG_PKSERVICE) {
879 buffer_append(&b, session_id2, session_id2_len);
880 skip = session_id2_len;
881 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
882 buffer_put_cstring(&b, authctxt->server_user);
883 buffer_put_cstring(&b, authctxt->service);
884 buffer_put_cstring(&b, authctxt->method->name);
885 buffer_put_char(&b, have_sig);
886 if (!(datafellows & SSH_BUG_PKAUTH))
887 buffer_put_cstring(&b, key_ssh_name(id->key));
888 buffer_put_string(&b, blob, bloblen);
892 /* append signature */
893 buffer_put_string(&b, signature, slen);
896 /* skip session id and packet type */
897 if (buffer_len(&b) < skip + 1)
898 fatal("userauth_pubkey: internal error");
899 buffer_consume(&b, skip + 1);
901 /* put remaining data from buffer into packet */
902 packet_start(SSH2_MSG_USERAUTH_REQUEST);
903 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
911 send_pubkey_test(Authctxt *authctxt, Identity *id)
914 u_int bloblen, have_sig = 0;
916 debug3("send_pubkey_test");
918 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
919 /* we cannot handle this key */
920 debug3("send_pubkey_test: cannot handle key");
923 /* register callback for USERAUTH_PK_OK message */
924 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
926 packet_start(SSH2_MSG_USERAUTH_REQUEST);
927 packet_put_cstring(authctxt->server_user);
928 packet_put_cstring(authctxt->service);
929 packet_put_cstring(authctxt->method->name);
930 packet_put_char(have_sig);
931 if (!(datafellows & SSH_BUG_PKAUTH))
932 packet_put_cstring(key_ssh_name(id->key));
933 packet_put_string(blob, bloblen);
940 load_identity_file(char *filename)
943 char prompt[300], *passphrase;
947 if (stat(filename, &st) < 0) {
948 debug3("no such identity: %s", filename);
951 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
952 if (private == NULL) {
953 if (options.batch_mode)
955 snprintf(prompt, sizeof prompt,
956 "Enter passphrase for key '%.100s': ", filename);
957 for (i = 0; i < options.number_of_password_prompts; i++) {
958 passphrase = read_passphrase(prompt, 0);
959 if (strcmp(passphrase, "") != 0) {
960 private = key_load_private_type(KEY_UNSPEC, filename,
964 debug2("no passphrase given, try next key");
967 memset(passphrase, 0, strlen(passphrase));
969 if (private != NULL || quit)
971 debug2("bad passphrase given, try again...");
978 * try keys in the following order:
979 * 1. agent keys that are found in the config file
980 * 2. other agent keys
981 * 3. keys that are only listed in the config file
984 pubkey_prepare(Authctxt *authctxt)
987 Idlist agent, files, *preferred;
989 AuthenticationConnection *ac;
993 TAILQ_INIT(&agent); /* keys from the agent */
994 TAILQ_INIT(&files); /* keys from the config file */
995 preferred = &authctxt->keys;
996 TAILQ_INIT(preferred); /* preferred order of keys */
998 /* list of keys stored in the filesystem */
999 for (i = 0; i < options.num_identity_files; i++) {
1000 key = options.identity_keys[i];
1001 if (key && key->type == KEY_RSA1)
1003 options.identity_keys[i] = NULL;
1004 id = xmalloc(sizeof(*id));
1005 memset(id, 0, sizeof(*id));
1007 id->filename = xstrdup(options.identity_files[i]);
1008 TAILQ_INSERT_TAIL(&files, id, next);
1010 /* list of keys supported by the agent */
1011 if ((ac = ssh_get_authentication_connection())) {
1012 for (key = ssh_get_first_identity(ac, &comment, 2);
1014 key = ssh_get_next_identity(ac, &comment, 2)) {
1016 TAILQ_FOREACH(id, &files, next) {
1017 /* agent keys from the config file are preferred */
1018 if (key_equal(key, id->key)) {
1021 TAILQ_REMOVE(&files, id, next);
1022 TAILQ_INSERT_TAIL(preferred, id, next);
1029 id = xmalloc(sizeof(*id));
1030 memset(id, 0, sizeof(*id));
1032 id->filename = comment;
1034 TAILQ_INSERT_TAIL(&agent, id, next);
1037 /* append remaining agent keys */
1038 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1039 TAILQ_REMOVE(&agent, id, next);
1040 TAILQ_INSERT_TAIL(preferred, id, next);
1042 authctxt->agent = ac;
1044 /* append remaining keys from the config file */
1045 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1046 TAILQ_REMOVE(&files, id, next);
1047 TAILQ_INSERT_TAIL(preferred, id, next);
1049 TAILQ_FOREACH(id, preferred, next) {
1050 debug2("key: %s (%p)", id->filename, id->key);
1055 pubkey_cleanup(Authctxt *authctxt)
1059 if (authctxt->agent != NULL)
1060 ssh_close_authentication_connection(authctxt->agent);
1061 for (id = TAILQ_FIRST(&authctxt->keys); id;
1062 id = TAILQ_FIRST(&authctxt->keys)) {
1063 TAILQ_REMOVE(&authctxt->keys, id, next);
1067 xfree(id->filename);
1073 userauth_pubkey(Authctxt *authctxt)
1078 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1081 TAILQ_REMOVE(&authctxt->keys, id, next);
1082 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1084 * send a test message if we have the public key. for
1085 * encrypted keys we cannot do this and have to load the
1086 * private key instead
1088 if (id->key && id->key->type != KEY_RSA1) {
1089 debug("Offering public key: %s", id->filename);
1090 sent = send_pubkey_test(authctxt, id);
1091 } else if (id->key == NULL) {
1092 debug("Trying private key: %s", id->filename);
1093 id->key = load_identity_file(id->filename);
1094 if (id->key != NULL) {
1096 sent = sign_and_send_pubkey(authctxt, id);
1108 * Send userauth request message specifying keyboard-interactive method.
1111 userauth_kbdint(Authctxt *authctxt)
1113 static int attempt = 0;
1115 if (attempt++ >= options.number_of_password_prompts)
1117 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1118 if (attempt > 1 && !authctxt->info_req_seen) {
1119 debug3("userauth_kbdint: disable: no info_req_seen");
1120 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1124 debug2("userauth_kbdint");
1125 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1126 packet_put_cstring(authctxt->server_user);
1127 packet_put_cstring(authctxt->service);
1128 packet_put_cstring(authctxt->method->name);
1129 packet_put_cstring(""); /* lang */
1130 packet_put_cstring(options.kbd_interactive_devices ?
1131 options.kbd_interactive_devices : "");
1134 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1139 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1142 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1144 Authctxt *authctxt = ctxt;
1145 char *name, *inst, *lang, *prompt, *response;
1146 u_int num_prompts, i;
1149 debug2("input_userauth_info_req");
1151 if (authctxt == NULL)
1152 fatal("input_userauth_info_req: no authentication context");
1154 authctxt->info_req_seen = 1;
1156 name = packet_get_string(NULL);
1157 inst = packet_get_string(NULL);
1158 lang = packet_get_string(NULL);
1159 if (strlen(name) > 0)
1161 if (strlen(inst) > 0)
1167 num_prompts = packet_get_int();
1169 * Begin to build info response packet based on prompts requested.
1170 * We commit to providing the correct number of responses, so if
1171 * further on we run into a problem that prevents this, we have to
1172 * be sure and clean this up and send a correct error response.
1174 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1175 packet_put_int(num_prompts);
1177 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1178 for (i = 0; i < num_prompts; i++) {
1179 prompt = packet_get_string(NULL);
1180 echo = packet_get_char();
1182 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1184 packet_put_cstring(response);
1185 memset(response, 0, strlen(response));
1189 packet_check_eom(); /* done with parsing incoming message. */
1191 packet_add_padding(64);
1196 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1197 u_char *data, u_int datalen)
1202 int to[2], from[2], status, version = 2;
1204 debug2("ssh_keysign called");
1206 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1207 error("ssh_keysign: no installed: %s", strerror(errno));
1210 if (fflush(stdout) != 0)
1211 error("ssh_keysign: fflush: %s", strerror(errno));
1213 error("ssh_keysign: pipe: %s", strerror(errno));
1216 if (pipe(from) < 0) {
1217 error("ssh_keysign: pipe: %s", strerror(errno));
1220 if ((pid = fork()) < 0) {
1221 error("ssh_keysign: fork: %s", strerror(errno));
1228 if (dup2(from[1], STDOUT_FILENO) < 0)
1229 fatal("ssh_keysign: dup2: %s", strerror(errno));
1231 if (dup2(to[0], STDIN_FILENO) < 0)
1232 fatal("ssh_keysign: dup2: %s", strerror(errno));
1235 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1236 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1243 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1244 buffer_put_string(&b, data, datalen);
1245 ssh_msg_send(to[1], version, &b);
1247 if (ssh_msg_recv(from[0], &b) < 0) {
1248 error("ssh_keysign: no reply");
1255 while (waitpid(pid, &status, 0) < 0)
1259 if (buffer_get_char(&b) != version) {
1260 error("ssh_keysign: bad version");
1264 *sigp = buffer_get_string(&b, lenp);
1271 userauth_hostbased(Authctxt *authctxt)
1273 Key *private = NULL;
1274 Sensitive *sensitive = authctxt->sensitive;
1276 u_char *signature, *blob;
1277 char *chost, *pkalg, *p;
1278 const char *service;
1280 int ok, i, len, found = 0;
1282 /* check for a useful key */
1283 for (i = 0; i < sensitive->nkeys; i++) {
1284 private = sensitive->keys[i];
1285 if (private && private->type != KEY_RSA1) {
1287 /* we take and free the key */
1288 sensitive->keys[i] = NULL;
1293 debug("No more client hostkeys for hostbased authentication.");
1296 if (key_to_blob(private, &blob, &blen) == 0) {
1300 /* figure out a name for the client host */
1301 p = get_local_name(packet_get_connection_in());
1303 error("userauth_hostbased: cannot get local ipaddr/name");
1307 len = strlen(p) + 2;
1308 chost = xmalloc(len);
1309 strlcpy(chost, p, len);
1310 strlcat(chost, ".", len);
1311 debug2("userauth_hostbased: chost %s", chost);
1314 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1316 pkalg = xstrdup(key_ssh_name(private));
1318 /* construct data */
1319 buffer_put_string(&b, session_id2, session_id2_len);
1320 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1321 buffer_put_cstring(&b, authctxt->server_user);
1322 buffer_put_cstring(&b, service);
1323 buffer_put_cstring(&b, authctxt->method->name);
1324 buffer_put_cstring(&b, pkalg);
1325 buffer_put_string(&b, blob, blen);
1326 buffer_put_cstring(&b, chost);
1327 buffer_put_cstring(&b, authctxt->local_user);
1331 if (sensitive->external_keysign)
1332 ok = ssh_keysign(private, &signature, &slen,
1333 buffer_ptr(&b), buffer_len(&b));
1335 ok = key_sign(private, &signature, &slen,
1336 buffer_ptr(&b), buffer_len(&b));
1340 error("key_sign failed");
1345 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1346 packet_put_cstring(authctxt->server_user);
1347 packet_put_cstring(authctxt->service);
1348 packet_put_cstring(authctxt->method->name);
1349 packet_put_cstring(pkalg);
1350 packet_put_string(blob, blen);
1351 packet_put_cstring(chost);
1352 packet_put_cstring(authctxt->local_user);
1353 packet_put_string(signature, slen);
1354 memset(signature, 's', slen);
1363 /* find auth method */
1366 * given auth method name, if configurable options permit this method fill
1367 * in auth_ident field and return true, otherwise return false.
1370 authmethod_is_enabled(Authmethod *method)
1374 /* return false if options indicate this method is disabled */
1375 if (method->enabled == NULL || *method->enabled == 0)
1377 /* return false if batch mode is enabled but method needs interactive mode */
1378 if (method->batch_flag != NULL && *method->batch_flag != 0)
1384 authmethod_lookup(const char *name)
1386 Authmethod *method = NULL;
1388 for (method = authmethods; method->name != NULL; method++)
1389 if (strcmp(name, method->name) == 0)
1391 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1395 /* XXX internal state */
1396 static Authmethod *current = NULL;
1397 static char *supported = NULL;
1398 static char *preferred = NULL;
1401 * Given the authentication method list sent by the server, return the
1402 * next method we should try. If the server initially sends a nil list,
1403 * use a built-in default list.
1406 authmethod_get(char *authlist)
1411 /* Use a suitable default if we're passed a nil list. */
1412 if (authlist == NULL || strlen(authlist) == 0)
1413 authlist = options.preferred_authentications;
1415 if (supported == NULL || strcmp(authlist, supported) != 0) {
1416 debug3("start over, passed a different list %s", authlist);
1417 if (supported != NULL)
1419 supported = xstrdup(authlist);
1420 preferred = options.preferred_authentications;
1421 debug3("preferred %s", preferred);
1423 } else if (current != NULL && authmethod_is_enabled(current))
1427 if ((name = match_list(preferred, supported, &next)) == NULL) {
1428 debug("No more authentication methods to try.");
1433 debug3("authmethod_lookup %s", name);
1434 debug3("remaining preferred: %s", preferred);
1435 if ((current = authmethod_lookup(name)) != NULL &&
1436 authmethod_is_enabled(current)) {
1437 debug3("authmethod_is_enabled %s", name);
1438 debug("Next authentication method: %s", name);
1445 authmethods_get(void)
1447 Authmethod *method = NULL;
1452 for (method = authmethods; method->name != NULL; method++) {
1453 if (authmethod_is_enabled(method)) {
1454 if (buffer_len(&b) > 0)
1455 buffer_append(&b, ",", 1);
1456 buffer_append(&b, method->name, strlen(method->name));
1459 buffer_append(&b, "\0", 1);
1460 list = xstrdup(buffer_ptr(&b));