1 /* $OpenBSD: sshconnect2.c,v 1.164 2007/05/17 23:53:41 jolan Exp $ */
3 * Copyright (c) 2000 Markus Friedl. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #include <sys/types.h>
29 #include <sys/socket.h>
42 #include "openbsd-compat/sys-queue.h"
53 #include "myproposal.h"
54 #include "sshconnect.h"
65 #include "pathnames.h"
73 extern char *client_version_string;
74 extern char *server_version_string;
75 extern Options options;
81 u_char *session_id2 = NULL;
82 u_int session_id2_len = 0;
85 struct sockaddr *xxx_hostaddr;
90 verify_host_key_callback(Key *hostkey)
92 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
93 fatal("Host key verification failed.");
98 ssh_kex2(char *host, struct sockaddr *hostaddr)
103 xxx_hostaddr = hostaddr;
105 if (options.ciphers == (char *)-1) {
106 logit("No valid ciphers for protocol version 2 given, using defaults.");
107 options.ciphers = NULL;
109 if (options.ciphers != NULL) {
110 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
111 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
113 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
114 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
115 myproposal[PROPOSAL_ENC_ALGS_STOC] =
116 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
117 if (options.compression) {
118 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
119 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
121 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
122 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
124 if (options.macs != NULL) {
125 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
126 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
128 if (options.hostkeyalgorithms != NULL)
129 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
130 options.hostkeyalgorithms;
132 if (options.rekey_limit)
133 packet_set_rekey_limit(options.rekey_limit);
135 /* start key exchange */
136 kex = kex_setup(myproposal);
137 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
138 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
139 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
140 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
141 kex->client_version_string=client_version_string;
142 kex->server_version_string=server_version_string;
143 kex->verify_host_key=&verify_host_key_callback;
147 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
149 session_id2 = kex->session_id;
150 session_id2_len = kex->session_id_len;
153 /* send 1st encrypted/maced/compressed message */
154 packet_start(SSH2_MSG_IGNORE);
155 packet_put_cstring("markus");
165 typedef struct Authctxt Authctxt;
166 typedef struct Authmethod Authmethod;
167 typedef struct identity Identity;
168 typedef struct idlist Idlist;
171 TAILQ_ENTRY(identity) next;
172 AuthenticationConnection *ac; /* set if agent supports key */
173 Key *key; /* public/private key */
174 char *filename; /* comment for agent-only keys */
176 int isprivate; /* key points to the private key */
178 TAILQ_HEAD(idlist, identity);
181 const char *server_user;
182 const char *local_user;
190 AuthenticationConnection *agent;
192 Sensitive *sensitive;
193 /* kbd-interactive */
199 char *name; /* string to compare against server's list */
200 int (*userauth)(Authctxt *authctxt);
201 int *enabled; /* flag in option struct that enables method */
202 int *batch_flag; /* flag in option struct that disables method */
205 void input_userauth_success(int, u_int32_t, void *);
206 void input_userauth_failure(int, u_int32_t, void *);
207 void input_userauth_banner(int, u_int32_t, void *);
208 void input_userauth_error(int, u_int32_t, void *);
209 void input_userauth_info_req(int, u_int32_t, void *);
210 void input_userauth_pk_ok(int, u_int32_t, void *);
211 void input_userauth_passwd_changereq(int, u_int32_t, void *);
213 int userauth_none(Authctxt *);
214 int userauth_pubkey(Authctxt *);
215 int userauth_passwd(Authctxt *);
216 int userauth_kbdint(Authctxt *);
217 int userauth_hostbased(Authctxt *);
218 int userauth_kerberos(Authctxt *);
221 int userauth_gssapi(Authctxt *authctxt);
222 void input_gssapi_response(int type, u_int32_t, void *);
223 void input_gssapi_token(int type, u_int32_t, void *);
224 void input_gssapi_hash(int type, u_int32_t, void *);
225 void input_gssapi_error(int, u_int32_t, void *);
226 void input_gssapi_errtok(int, u_int32_t, void *);
229 void userauth(Authctxt *, char *);
231 static int sign_and_send_pubkey(Authctxt *, Identity *);
232 static void pubkey_prepare(Authctxt *);
233 static void pubkey_cleanup(Authctxt *);
234 static Key *load_identity_file(char *);
236 static Authmethod *authmethod_get(char *authlist);
237 static Authmethod *authmethod_lookup(const char *name);
238 static char *authmethods_get(void);
240 Authmethod authmethods[] = {
244 &options.gss_authentication,
249 &options.hostbased_authentication,
253 &options.pubkey_authentication,
255 {"keyboard-interactive",
257 &options.kbd_interactive_authentication,
258 &options.batch_mode},
261 &options.password_authentication,
262 &options.batch_mode},
267 {NULL, NULL, NULL, NULL}
271 ssh_userauth2(const char *local_user, const char *server_user, char *host,
272 Sensitive *sensitive)
277 if (options.challenge_response_authentication)
278 options.kbd_interactive_authentication = 1;
280 packet_start(SSH2_MSG_SERVICE_REQUEST);
281 packet_put_cstring("ssh-userauth");
283 debug("SSH2_MSG_SERVICE_REQUEST sent");
285 type = packet_read();
286 if (type != SSH2_MSG_SERVICE_ACCEPT)
287 fatal("Server denied authentication request: %d", type);
288 if (packet_remaining() > 0) {
289 char *reply = packet_get_string(NULL);
290 debug2("service_accept: %s", reply);
293 debug2("buggy server: service_accept w/o service");
296 debug("SSH2_MSG_SERVICE_ACCEPT received");
298 if (options.preferred_authentications == NULL)
299 options.preferred_authentications = authmethods_get();
301 /* setup authentication context */
302 memset(&authctxt, 0, sizeof(authctxt));
303 pubkey_prepare(&authctxt);
304 authctxt.server_user = server_user;
305 authctxt.local_user = local_user;
306 authctxt.host = host;
307 authctxt.service = "ssh-connection"; /* service name */
308 authctxt.success = 0;
309 authctxt.method = authmethod_lookup("none");
310 authctxt.authlist = NULL;
311 authctxt.methoddata = NULL;
312 authctxt.sensitive = sensitive;
313 authctxt.info_req_seen = 0;
314 if (authctxt.method == NULL)
315 fatal("ssh_userauth2: internal error: cannot send userauth none request");
317 /* initial userauth request */
318 userauth_none(&authctxt);
320 dispatch_init(&input_userauth_error);
321 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
322 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
323 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
324 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
326 pubkey_cleanup(&authctxt);
327 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
329 debug("Authentication succeeded (%s).", authctxt.method->name);
333 userauth(Authctxt *authctxt, char *authlist)
335 if (authctxt->methoddata) {
336 xfree(authctxt->methoddata);
337 authctxt->methoddata = NULL;
339 if (authlist == NULL) {
340 authlist = authctxt->authlist;
342 if (authctxt->authlist)
343 xfree(authctxt->authlist);
344 authctxt->authlist = authlist;
347 Authmethod *method = authmethod_get(authlist);
349 fatal("Permission denied (%s).", authlist);
350 authctxt->method = method;
352 /* reset the per method handler */
353 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
354 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
356 /* and try new method */
357 if (method->userauth(authctxt) != 0) {
358 debug2("we sent a %s packet, wait for reply", method->name);
361 debug2("we did not send a packet, disable method");
362 method->enabled = NULL;
368 input_userauth_error(int type, u_int32_t seq, void *ctxt)
370 fatal("input_userauth_error: bad message during authentication: "
375 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
379 debug3("input_userauth_banner");
380 msg = packet_get_string(NULL);
381 lang = packet_get_string(NULL);
382 if (options.log_level >= SYSLOG_LEVEL_INFO)
383 fprintf(stderr, "%s", msg);
389 input_userauth_success(int type, u_int32_t seq, void *ctxt)
391 Authctxt *authctxt = ctxt;
392 if (authctxt == NULL)
393 fatal("input_userauth_success: no authentication context");
394 if (authctxt->authlist) {
395 xfree(authctxt->authlist);
396 authctxt->authlist = NULL;
398 if (authctxt->methoddata) {
399 xfree(authctxt->methoddata);
400 authctxt->methoddata = NULL;
402 authctxt->success = 1; /* break out */
406 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
408 Authctxt *authctxt = ctxt;
409 char *authlist = NULL;
412 if (authctxt == NULL)
413 fatal("input_userauth_failure: no authentication context");
415 authlist = packet_get_string(NULL);
416 partial = packet_get_char();
420 logit("Authenticated with partial success.");
421 debug("Authentications that can continue: %s", authlist);
423 userauth(authctxt, authlist);
426 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
428 Authctxt *authctxt = ctxt;
432 int pktype, sent = 0;
437 if (authctxt == NULL)
438 fatal("input_userauth_pk_ok: no authentication context");
439 if (datafellows & SSH_BUG_PKOK) {
440 /* this is similar to SSH_BUG_PKAUTH */
441 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
442 pkblob = packet_get_string(&blen);
444 buffer_append(&b, pkblob, blen);
445 pkalg = buffer_get_string(&b, &alen);
448 pkalg = packet_get_string(&alen);
449 pkblob = packet_get_string(&blen);
453 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
455 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
456 debug("unknown pkalg %s", pkalg);
459 if ((key = key_from_blob(pkblob, blen)) == NULL) {
460 debug("no key from blob. pkalg %s", pkalg);
463 if (key->type != pktype) {
464 error("input_userauth_pk_ok: type mismatch "
465 "for decoded key (received %d, expected %d)",
469 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
470 debug2("input_userauth_pk_ok: fp %s", fp);
474 * search keys in the reverse order, because last candidate has been
475 * moved to the end of the queue. this also avoids confusion by
478 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
479 if (key_equal(key, id->key)) {
480 sent = sign_and_send_pubkey(authctxt, id);
490 /* try another method if we did not send a packet */
492 userauth(authctxt, NULL);
497 userauth_gssapi(Authctxt *authctxt)
499 Gssctxt *gssctxt = NULL;
500 static gss_OID_set gss_supported = NULL;
501 static u_int mech = 0;
505 /* Try one GSSAPI method at a time, rather than sending them all at
508 if (gss_supported == NULL)
509 gss_indicate_mechs(&min, &gss_supported);
511 /* Check to see if the mechanism is usable before we offer it */
512 while (mech < gss_supported->count && !ok) {
513 /* My DER encoding requires length<128 */
514 if (gss_supported->elements[mech].length < 128 &&
515 ssh_gssapi_check_mechanism(&gssctxt,
516 &gss_supported->elements[mech], authctxt->host)) {
517 ok = 1; /* Mechanism works */
526 authctxt->methoddata=(void *)gssctxt;
528 packet_start(SSH2_MSG_USERAUTH_REQUEST);
529 packet_put_cstring(authctxt->server_user);
530 packet_put_cstring(authctxt->service);
531 packet_put_cstring(authctxt->method->name);
535 packet_put_int((gss_supported->elements[mech].length) + 2);
536 packet_put_char(SSH_GSS_OIDTYPE);
537 packet_put_char(gss_supported->elements[mech].length);
538 packet_put_raw(gss_supported->elements[mech].elements,
539 gss_supported->elements[mech].length);
543 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
544 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
545 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
546 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
548 mech++; /* Move along to next candidate */
554 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
556 Authctxt *authctxt = ctxt;
557 Gssctxt *gssctxt = authctxt->methoddata;
558 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
559 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
560 gss_buffer_desc gssbuf;
561 OM_uint32 status, ms, flags;
564 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
565 recv_tok, &send_tok, &flags);
567 if (send_tok.length > 0) {
568 if (GSS_ERROR(status))
569 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
571 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
573 packet_put_string(send_tok.value, send_tok.length);
575 gss_release_buffer(&ms, &send_tok);
578 if (status == GSS_S_COMPLETE) {
579 /* send either complete or MIC, depending on mechanism */
580 if (!(flags & GSS_C_INTEG_FLAG)) {
581 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
584 ssh_gssapi_buildmic(&b, authctxt->server_user,
585 authctxt->service, "gssapi-with-mic");
587 gssbuf.value = buffer_ptr(&b);
588 gssbuf.length = buffer_len(&b);
590 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
592 if (!GSS_ERROR(status)) {
593 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
594 packet_put_string(mic.value, mic.length);
600 gss_release_buffer(&ms, &mic);
608 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
610 Authctxt *authctxt = ctxt;
615 if (authctxt == NULL)
616 fatal("input_gssapi_response: no authentication context");
617 gssctxt = authctxt->methoddata;
620 oidv = packet_get_string(&oidlen);
623 oidv[0] != SSH_GSS_OIDTYPE ||
624 oidv[1] != oidlen - 2) {
626 debug("Badly encoded mechanism OID received");
627 userauth(authctxt, NULL);
631 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
632 fatal("Server returned different OID than expected");
638 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
639 /* Start again with next method on list */
640 debug("Trying to start again");
641 userauth(authctxt, NULL);
647 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
649 Authctxt *authctxt = ctxt;
650 gss_buffer_desc recv_tok;
654 if (authctxt == NULL)
655 fatal("input_gssapi_response: no authentication context");
657 recv_tok.value = packet_get_string(&slen);
658 recv_tok.length = slen; /* safe typecast */
662 status = process_gssapi_token(ctxt, &recv_tok);
664 xfree(recv_tok.value);
666 if (GSS_ERROR(status)) {
667 /* Start again with the next method in the list */
668 userauth(authctxt, NULL);
674 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
676 Authctxt *authctxt = ctxt;
678 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
679 gss_buffer_desc recv_tok;
680 OM_uint32 status, ms;
683 if (authctxt == NULL)
684 fatal("input_gssapi_response: no authentication context");
685 gssctxt = authctxt->methoddata;
687 recv_tok.value = packet_get_string(&len);
688 recv_tok.length = len;
692 /* Stick it into GSSAPI and see what it says */
693 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
694 &recv_tok, &send_tok, NULL);
696 xfree(recv_tok.value);
697 gss_release_buffer(&ms, &send_tok);
699 /* Server will be returning a failed packet after this one */
703 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
709 maj=packet_get_int();
710 min=packet_get_int();
711 msg=packet_get_string(NULL);
712 lang=packet_get_string(NULL);
716 debug("Server GSSAPI Error:\n%s", msg);
723 userauth_none(Authctxt *authctxt)
725 /* initial userauth request */
726 packet_start(SSH2_MSG_USERAUTH_REQUEST);
727 packet_put_cstring(authctxt->server_user);
728 packet_put_cstring(authctxt->service);
729 packet_put_cstring(authctxt->method->name);
735 userauth_passwd(Authctxt *authctxt)
737 static int attempt = 0;
741 if (attempt++ >= options.number_of_password_prompts)
745 error("Permission denied, please try again.");
747 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
748 authctxt->server_user, authctxt->host);
749 password = read_passphrase(prompt, 0);
750 packet_start(SSH2_MSG_USERAUTH_REQUEST);
751 packet_put_cstring(authctxt->server_user);
752 packet_put_cstring(authctxt->service);
753 packet_put_cstring(authctxt->method->name);
755 packet_put_cstring(password);
756 memset(password, 0, strlen(password));
758 packet_add_padding(64);
761 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
762 &input_userauth_passwd_changereq);
767 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
770 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
772 Authctxt *authctxt = ctxt;
773 char *info, *lang, *password = NULL, *retype = NULL;
776 debug2("input_userauth_passwd_changereq");
778 if (authctxt == NULL)
779 fatal("input_userauth_passwd_changereq: "
780 "no authentication context");
782 info = packet_get_string(NULL);
783 lang = packet_get_string(NULL);
784 if (strlen(info) > 0)
788 packet_start(SSH2_MSG_USERAUTH_REQUEST);
789 packet_put_cstring(authctxt->server_user);
790 packet_put_cstring(authctxt->service);
791 packet_put_cstring(authctxt->method->name);
792 packet_put_char(1); /* additional info */
793 snprintf(prompt, sizeof(prompt),
794 "Enter %.30s@%.128s's old password: ",
795 authctxt->server_user, authctxt->host);
796 password = read_passphrase(prompt, 0);
797 packet_put_cstring(password);
798 memset(password, 0, strlen(password));
801 while (password == NULL) {
802 snprintf(prompt, sizeof(prompt),
803 "Enter %.30s@%.128s's new password: ",
804 authctxt->server_user, authctxt->host);
805 password = read_passphrase(prompt, RP_ALLOW_EOF);
806 if (password == NULL) {
810 snprintf(prompt, sizeof(prompt),
811 "Retype %.30s@%.128s's new password: ",
812 authctxt->server_user, authctxt->host);
813 retype = read_passphrase(prompt, 0);
814 if (strcmp(password, retype) != 0) {
815 memset(password, 0, strlen(password));
817 logit("Mismatch; try again, EOF to quit.");
820 memset(retype, 0, strlen(retype));
823 packet_put_cstring(password);
824 memset(password, 0, strlen(password));
826 packet_add_padding(64);
829 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
830 &input_userauth_passwd_changereq);
834 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
835 u_char *data, u_int datalen)
840 /* the agent supports this key */
842 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
845 * we have already loaded the private key or
846 * the private key is stored in external hardware
848 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
849 return (key_sign(id->key, sigp, lenp, data, datalen));
850 /* load the private key from the file */
851 if ((prv = load_identity_file(id->filename)) == NULL)
853 ret = key_sign(prv, sigp, lenp, data, datalen);
859 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
862 u_char *blob, *signature;
868 debug3("sign_and_send_pubkey");
870 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
871 /* we cannot handle this key */
872 debug3("sign_and_send_pubkey: cannot handle key");
875 /* data to be signed */
877 if (datafellows & SSH_OLD_SESSIONID) {
878 buffer_append(&b, session_id2, session_id2_len);
879 skip = session_id2_len;
881 buffer_put_string(&b, session_id2, session_id2_len);
882 skip = buffer_len(&b);
884 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
885 buffer_put_cstring(&b, authctxt->server_user);
886 buffer_put_cstring(&b,
887 datafellows & SSH_BUG_PKSERVICE ?
890 if (datafellows & SSH_BUG_PKAUTH) {
891 buffer_put_char(&b, have_sig);
893 buffer_put_cstring(&b, authctxt->method->name);
894 buffer_put_char(&b, have_sig);
895 buffer_put_cstring(&b, key_ssh_name(id->key));
897 buffer_put_string(&b, blob, bloblen);
899 /* generate signature */
900 ret = identity_sign(id, &signature, &slen,
901 buffer_ptr(&b), buffer_len(&b));
910 if (datafellows & SSH_BUG_PKSERVICE) {
912 buffer_append(&b, session_id2, session_id2_len);
913 skip = session_id2_len;
914 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
915 buffer_put_cstring(&b, authctxt->server_user);
916 buffer_put_cstring(&b, authctxt->service);
917 buffer_put_cstring(&b, authctxt->method->name);
918 buffer_put_char(&b, have_sig);
919 if (!(datafellows & SSH_BUG_PKAUTH))
920 buffer_put_cstring(&b, key_ssh_name(id->key));
921 buffer_put_string(&b, blob, bloblen);
925 /* append signature */
926 buffer_put_string(&b, signature, slen);
929 /* skip session id and packet type */
930 if (buffer_len(&b) < skip + 1)
931 fatal("userauth_pubkey: internal error");
932 buffer_consume(&b, skip + 1);
934 /* put remaining data from buffer into packet */
935 packet_start(SSH2_MSG_USERAUTH_REQUEST);
936 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
944 send_pubkey_test(Authctxt *authctxt, Identity *id)
947 u_int bloblen, have_sig = 0;
949 debug3("send_pubkey_test");
951 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
952 /* we cannot handle this key */
953 debug3("send_pubkey_test: cannot handle key");
956 /* register callback for USERAUTH_PK_OK message */
957 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
959 packet_start(SSH2_MSG_USERAUTH_REQUEST);
960 packet_put_cstring(authctxt->server_user);
961 packet_put_cstring(authctxt->service);
962 packet_put_cstring(authctxt->method->name);
963 packet_put_char(have_sig);
964 if (!(datafellows & SSH_BUG_PKAUTH))
965 packet_put_cstring(key_ssh_name(id->key));
966 packet_put_string(blob, bloblen);
973 load_identity_file(char *filename)
976 char prompt[300], *passphrase;
977 int perm_ok, quit, i;
980 if (stat(filename, &st) < 0) {
981 debug3("no such identity: %s", filename);
984 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
987 if (private == NULL) {
988 if (options.batch_mode)
990 snprintf(prompt, sizeof prompt,
991 "Enter passphrase for key '%.100s': ", filename);
992 for (i = 0; i < options.number_of_password_prompts; i++) {
993 passphrase = read_passphrase(prompt, 0);
994 if (strcmp(passphrase, "") != 0) {
995 private = key_load_private_type(KEY_UNSPEC,
996 filename, passphrase, NULL, NULL);
999 debug2("no passphrase given, try next key");
1002 memset(passphrase, 0, strlen(passphrase));
1004 if (private != NULL || quit)
1006 debug2("bad passphrase given, try again...");
1013 * try keys in the following order:
1014 * 1. agent keys that are found in the config file
1015 * 2. other agent keys
1016 * 3. keys that are only listed in the config file
1019 pubkey_prepare(Authctxt *authctxt)
1022 Idlist agent, files, *preferred;
1024 AuthenticationConnection *ac;
1028 TAILQ_INIT(&agent); /* keys from the agent */
1029 TAILQ_INIT(&files); /* keys from the config file */
1030 preferred = &authctxt->keys;
1031 TAILQ_INIT(preferred); /* preferred order of keys */
1033 /* list of keys stored in the filesystem */
1034 for (i = 0; i < options.num_identity_files; i++) {
1035 key = options.identity_keys[i];
1036 if (key && key->type == KEY_RSA1)
1038 options.identity_keys[i] = NULL;
1039 id = xcalloc(1, sizeof(*id));
1041 id->filename = xstrdup(options.identity_files[i]);
1042 TAILQ_INSERT_TAIL(&files, id, next);
1044 /* list of keys supported by the agent */
1045 if ((ac = ssh_get_authentication_connection())) {
1046 for (key = ssh_get_first_identity(ac, &comment, 2);
1048 key = ssh_get_next_identity(ac, &comment, 2)) {
1050 TAILQ_FOREACH(id, &files, next) {
1051 /* agent keys from the config file are preferred */
1052 if (key_equal(key, id->key)) {
1055 TAILQ_REMOVE(&files, id, next);
1056 TAILQ_INSERT_TAIL(preferred, id, next);
1062 if (!found && !options.identities_only) {
1063 id = xcalloc(1, sizeof(*id));
1065 id->filename = comment;
1067 TAILQ_INSERT_TAIL(&agent, id, next);
1070 /* append remaining agent keys */
1071 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1072 TAILQ_REMOVE(&agent, id, next);
1073 TAILQ_INSERT_TAIL(preferred, id, next);
1075 authctxt->agent = ac;
1077 /* append remaining keys from the config file */
1078 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1079 TAILQ_REMOVE(&files, id, next);
1080 TAILQ_INSERT_TAIL(preferred, id, next);
1082 TAILQ_FOREACH(id, preferred, next) {
1083 debug2("key: %s (%p)", id->filename, id->key);
1088 pubkey_cleanup(Authctxt *authctxt)
1092 if (authctxt->agent != NULL)
1093 ssh_close_authentication_connection(authctxt->agent);
1094 for (id = TAILQ_FIRST(&authctxt->keys); id;
1095 id = TAILQ_FIRST(&authctxt->keys)) {
1096 TAILQ_REMOVE(&authctxt->keys, id, next);
1100 xfree(id->filename);
1106 userauth_pubkey(Authctxt *authctxt)
1111 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1114 /* move key to the end of the queue */
1115 TAILQ_REMOVE(&authctxt->keys, id, next);
1116 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1118 * send a test message if we have the public key. for
1119 * encrypted keys we cannot do this and have to load the
1120 * private key instead
1122 if (id->key && id->key->type != KEY_RSA1) {
1123 debug("Offering public key: %s", id->filename);
1124 sent = send_pubkey_test(authctxt, id);
1125 } else if (id->key == NULL) {
1126 debug("Trying private key: %s", id->filename);
1127 id->key = load_identity_file(id->filename);
1128 if (id->key != NULL) {
1130 sent = sign_and_send_pubkey(authctxt, id);
1142 * Send userauth request message specifying keyboard-interactive method.
1145 userauth_kbdint(Authctxt *authctxt)
1147 static int attempt = 0;
1149 if (attempt++ >= options.number_of_password_prompts)
1151 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1152 if (attempt > 1 && !authctxt->info_req_seen) {
1153 debug3("userauth_kbdint: disable: no info_req_seen");
1154 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1158 debug2("userauth_kbdint");
1159 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1160 packet_put_cstring(authctxt->server_user);
1161 packet_put_cstring(authctxt->service);
1162 packet_put_cstring(authctxt->method->name);
1163 packet_put_cstring(""); /* lang */
1164 packet_put_cstring(options.kbd_interactive_devices ?
1165 options.kbd_interactive_devices : "");
1168 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1173 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1176 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1178 Authctxt *authctxt = ctxt;
1179 char *name, *inst, *lang, *prompt, *response;
1180 u_int num_prompts, i;
1183 debug2("input_userauth_info_req");
1185 if (authctxt == NULL)
1186 fatal("input_userauth_info_req: no authentication context");
1188 authctxt->info_req_seen = 1;
1190 name = packet_get_string(NULL);
1191 inst = packet_get_string(NULL);
1192 lang = packet_get_string(NULL);
1193 if (strlen(name) > 0)
1195 if (strlen(inst) > 0)
1201 num_prompts = packet_get_int();
1203 * Begin to build info response packet based on prompts requested.
1204 * We commit to providing the correct number of responses, so if
1205 * further on we run into a problem that prevents this, we have to
1206 * be sure and clean this up and send a correct error response.
1208 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1209 packet_put_int(num_prompts);
1211 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1212 for (i = 0; i < num_prompts; i++) {
1213 prompt = packet_get_string(NULL);
1214 echo = packet_get_char();
1216 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1218 packet_put_cstring(response);
1219 memset(response, 0, strlen(response));
1223 packet_check_eom(); /* done with parsing incoming message. */
1225 packet_add_padding(64);
1230 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1231 u_char *data, u_int datalen)
1236 int to[2], from[2], status, version = 2;
1238 debug2("ssh_keysign called");
1240 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1241 error("ssh_keysign: no installed: %s", strerror(errno));
1244 if (fflush(stdout) != 0)
1245 error("ssh_keysign: fflush: %s", strerror(errno));
1247 error("ssh_keysign: pipe: %s", strerror(errno));
1250 if (pipe(from) < 0) {
1251 error("ssh_keysign: pipe: %s", strerror(errno));
1254 if ((pid = fork()) < 0) {
1255 error("ssh_keysign: fork: %s", strerror(errno));
1259 permanently_drop_suid(getuid());
1261 if (dup2(from[1], STDOUT_FILENO) < 0)
1262 fatal("ssh_keysign: dup2: %s", strerror(errno));
1264 if (dup2(to[0], STDIN_FILENO) < 0)
1265 fatal("ssh_keysign: dup2: %s", strerror(errno));
1268 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1269 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1276 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1277 buffer_put_string(&b, data, datalen);
1278 if (ssh_msg_send(to[1], version, &b) == -1)
1279 fatal("ssh_keysign: couldn't send request");
1281 if (ssh_msg_recv(from[0], &b) < 0) {
1282 error("ssh_keysign: no reply");
1289 while (waitpid(pid, &status, 0) < 0)
1293 if (buffer_get_char(&b) != version) {
1294 error("ssh_keysign: bad version");
1298 *sigp = buffer_get_string(&b, lenp);
1305 userauth_hostbased(Authctxt *authctxt)
1307 Key *private = NULL;
1308 Sensitive *sensitive = authctxt->sensitive;
1310 u_char *signature, *blob;
1311 char *chost, *pkalg, *p, myname[NI_MAXHOST];
1312 const char *service;
1314 int ok, i, len, found = 0;
1316 /* check for a useful key */
1317 for (i = 0; i < sensitive->nkeys; i++) {
1318 private = sensitive->keys[i];
1319 if (private && private->type != KEY_RSA1) {
1321 /* we take and free the key */
1322 sensitive->keys[i] = NULL;
1327 debug("No more client hostkeys for hostbased authentication.");
1330 if (key_to_blob(private, &blob, &blen) == 0) {
1334 /* figure out a name for the client host */
1336 if (packet_connection_is_on_socket())
1337 p = get_local_name(packet_get_connection_in());
1339 if (gethostname(myname, sizeof(myname)) == -1) {
1340 verbose("userauth_hostbased: gethostname: %s",
1343 p = xstrdup(myname);
1346 error("userauth_hostbased: cannot get local ipaddr/name");
1351 len = strlen(p) + 2;
1352 xasprintf(&chost, "%s.", p);
1353 debug2("userauth_hostbased: chost %s", chost);
1356 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1358 pkalg = xstrdup(key_ssh_name(private));
1360 /* construct data */
1361 buffer_put_string(&b, session_id2, session_id2_len);
1362 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1363 buffer_put_cstring(&b, authctxt->server_user);
1364 buffer_put_cstring(&b, service);
1365 buffer_put_cstring(&b, authctxt->method->name);
1366 buffer_put_cstring(&b, pkalg);
1367 buffer_put_string(&b, blob, blen);
1368 buffer_put_cstring(&b, chost);
1369 buffer_put_cstring(&b, authctxt->local_user);
1373 if (sensitive->external_keysign)
1374 ok = ssh_keysign(private, &signature, &slen,
1375 buffer_ptr(&b), buffer_len(&b));
1377 ok = key_sign(private, &signature, &slen,
1378 buffer_ptr(&b), buffer_len(&b));
1382 error("key_sign failed");
1388 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1389 packet_put_cstring(authctxt->server_user);
1390 packet_put_cstring(authctxt->service);
1391 packet_put_cstring(authctxt->method->name);
1392 packet_put_cstring(pkalg);
1393 packet_put_string(blob, blen);
1394 packet_put_cstring(chost);
1395 packet_put_cstring(authctxt->local_user);
1396 packet_put_string(signature, slen);
1397 memset(signature, 's', slen);
1407 /* find auth method */
1410 * given auth method name, if configurable options permit this method fill
1411 * in auth_ident field and return true, otherwise return false.
1414 authmethod_is_enabled(Authmethod *method)
1418 /* return false if options indicate this method is disabled */
1419 if (method->enabled == NULL || *method->enabled == 0)
1421 /* return false if batch mode is enabled but method needs interactive mode */
1422 if (method->batch_flag != NULL && *method->batch_flag != 0)
1428 authmethod_lookup(const char *name)
1430 Authmethod *method = NULL;
1432 for (method = authmethods; method->name != NULL; method++)
1433 if (strcmp(name, method->name) == 0)
1435 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1439 /* XXX internal state */
1440 static Authmethod *current = NULL;
1441 static char *supported = NULL;
1442 static char *preferred = NULL;
1445 * Given the authentication method list sent by the server, return the
1446 * next method we should try. If the server initially sends a nil list,
1447 * use a built-in default list.
1450 authmethod_get(char *authlist)
1455 /* Use a suitable default if we're passed a nil list. */
1456 if (authlist == NULL || strlen(authlist) == 0)
1457 authlist = options.preferred_authentications;
1459 if (supported == NULL || strcmp(authlist, supported) != 0) {
1460 debug3("start over, passed a different list %s", authlist);
1461 if (supported != NULL)
1463 supported = xstrdup(authlist);
1464 preferred = options.preferred_authentications;
1465 debug3("preferred %s", preferred);
1467 } else if (current != NULL && authmethod_is_enabled(current))
1471 if ((name = match_list(preferred, supported, &next)) == NULL) {
1472 debug("No more authentication methods to try.");
1477 debug3("authmethod_lookup %s", name);
1478 debug3("remaining preferred: %s", preferred);
1479 if ((current = authmethod_lookup(name)) != NULL &&
1480 authmethod_is_enabled(current)) {
1481 debug3("authmethod_is_enabled %s", name);
1482 debug("Next authentication method: %s", name);
1489 authmethods_get(void)
1491 Authmethod *method = NULL;
1496 for (method = authmethods; method->name != NULL; method++) {
1497 if (authmethod_is_enabled(method)) {
1498 if (buffer_len(&b) > 0)
1499 buffer_append(&b, ",", 1);
1500 buffer_append(&b, method->name, strlen(method->name));
1503 buffer_append(&b, "\0", 1);
1504 list = xstrdup(buffer_ptr(&b));