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 1.147 2006/03/07 09:07:40 djm Exp $");
28 #include <sys/types.h>
32 #include "openbsd-compat/sys-queue.h"
43 #include "myproposal.h"
44 #include "sshconnect.h"
55 #include "pathnames.h"
62 extern char *client_version_string;
63 extern char *server_version_string;
64 extern Options options;
70 u_char *session_id2 = NULL;
71 u_int session_id2_len = 0;
74 struct sockaddr *xxx_hostaddr;
79 verify_host_key_callback(Key *hostkey)
81 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
82 fatal("Host key verification failed.");
87 ssh_kex2(char *host, struct sockaddr *hostaddr)
92 xxx_hostaddr = hostaddr;
94 if (options.ciphers == (char *)-1) {
95 logit("No valid ciphers for protocol version 2 given, using defaults.");
96 options.ciphers = NULL;
98 if (options.ciphers != NULL) {
99 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
100 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
102 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
103 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
104 myproposal[PROPOSAL_ENC_ALGS_STOC] =
105 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
106 if (options.compression) {
107 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
108 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
110 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
111 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
113 if (options.macs != NULL) {
114 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
115 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
117 if (options.hostkeyalgorithms != NULL)
118 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
119 options.hostkeyalgorithms;
121 if (options.rekey_limit)
122 packet_set_rekey_limit(options.rekey_limit);
124 /* start key exchange */
125 kex = kex_setup(myproposal);
126 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
127 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
128 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
129 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
130 kex->client_version_string=client_version_string;
131 kex->server_version_string=server_version_string;
132 kex->verify_host_key=&verify_host_key_callback;
136 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
138 session_id2 = kex->session_id;
139 session_id2_len = kex->session_id_len;
142 /* send 1st encrypted/maced/compressed message */
143 packet_start(SSH2_MSG_IGNORE);
144 packet_put_cstring("markus");
154 typedef struct Authctxt Authctxt;
155 typedef struct Authmethod Authmethod;
156 typedef struct identity Identity;
157 typedef struct idlist Idlist;
160 TAILQ_ENTRY(identity) next;
161 AuthenticationConnection *ac; /* set if agent supports key */
162 Key *key; /* public/private key */
163 char *filename; /* comment for agent-only keys */
165 int isprivate; /* key points to the private key */
167 TAILQ_HEAD(idlist, identity);
170 const char *server_user;
171 const char *local_user;
179 AuthenticationConnection *agent;
181 Sensitive *sensitive;
182 /* kbd-interactive */
188 char *name; /* string to compare against server's list */
189 int (*userauth)(Authctxt *authctxt);
190 int *enabled; /* flag in option struct that enables method */
191 int *batch_flag; /* flag in option struct that disables method */
194 void input_userauth_success(int, u_int32_t, void *);
195 void input_userauth_failure(int, u_int32_t, void *);
196 void input_userauth_banner(int, u_int32_t, void *);
197 void input_userauth_error(int, u_int32_t, void *);
198 void input_userauth_info_req(int, u_int32_t, void *);
199 void input_userauth_pk_ok(int, u_int32_t, void *);
200 void input_userauth_passwd_changereq(int, u_int32_t, void *);
202 int userauth_none(Authctxt *);
203 int userauth_pubkey(Authctxt *);
204 int userauth_passwd(Authctxt *);
205 int userauth_kbdint(Authctxt *);
206 int userauth_hostbased(Authctxt *);
207 int userauth_kerberos(Authctxt *);
210 int userauth_gssapi(Authctxt *authctxt);
211 void input_gssapi_response(int type, u_int32_t, void *);
212 void input_gssapi_token(int type, u_int32_t, void *);
213 void input_gssapi_hash(int type, u_int32_t, void *);
214 void input_gssapi_error(int, u_int32_t, void *);
215 void input_gssapi_errtok(int, u_int32_t, void *);
218 void userauth(Authctxt *, char *);
220 static int sign_and_send_pubkey(Authctxt *, Identity *);
221 static void pubkey_prepare(Authctxt *);
222 static void pubkey_cleanup(Authctxt *);
223 static Key *load_identity_file(char *);
225 static Authmethod *authmethod_get(char *authlist);
226 static Authmethod *authmethod_lookup(const char *name);
227 static char *authmethods_get(void);
229 Authmethod authmethods[] = {
233 &options.gss_authentication,
238 &options.hostbased_authentication,
242 &options.pubkey_authentication,
244 {"keyboard-interactive",
246 &options.kbd_interactive_authentication,
247 &options.batch_mode},
250 &options.password_authentication,
251 &options.batch_mode},
256 {NULL, NULL, NULL, NULL}
260 ssh_userauth2(const char *local_user, const char *server_user, char *host,
261 Sensitive *sensitive)
266 if (options.challenge_response_authentication)
267 options.kbd_interactive_authentication = 1;
269 packet_start(SSH2_MSG_SERVICE_REQUEST);
270 packet_put_cstring("ssh-userauth");
272 debug("SSH2_MSG_SERVICE_REQUEST sent");
274 type = packet_read();
275 if (type != SSH2_MSG_SERVICE_ACCEPT)
276 fatal("Server denied authentication request: %d", type);
277 if (packet_remaining() > 0) {
278 char *reply = packet_get_string(NULL);
279 debug2("service_accept: %s", reply);
282 debug2("buggy server: service_accept w/o service");
285 debug("SSH2_MSG_SERVICE_ACCEPT received");
287 if (options.preferred_authentications == NULL)
288 options.preferred_authentications = authmethods_get();
290 /* setup authentication context */
291 memset(&authctxt, 0, sizeof(authctxt));
292 pubkey_prepare(&authctxt);
293 authctxt.server_user = server_user;
294 authctxt.local_user = local_user;
295 authctxt.host = host;
296 authctxt.service = "ssh-connection"; /* service name */
297 authctxt.success = 0;
298 authctxt.method = authmethod_lookup("none");
299 authctxt.authlist = NULL;
300 authctxt.methoddata = NULL;
301 authctxt.sensitive = sensitive;
302 authctxt.info_req_seen = 0;
303 if (authctxt.method == NULL)
304 fatal("ssh_userauth2: internal error: cannot send userauth none request");
306 /* initial userauth request */
307 userauth_none(&authctxt);
309 dispatch_init(&input_userauth_error);
310 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
311 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
312 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
313 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
315 pubkey_cleanup(&authctxt);
316 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
318 debug("Authentication succeeded (%s).", authctxt.method->name);
322 userauth(Authctxt *authctxt, char *authlist)
324 if (authctxt->methoddata) {
325 xfree(authctxt->methoddata);
326 authctxt->methoddata = NULL;
328 if (authlist == NULL) {
329 authlist = authctxt->authlist;
331 if (authctxt->authlist)
332 xfree(authctxt->authlist);
333 authctxt->authlist = authlist;
336 Authmethod *method = authmethod_get(authlist);
338 fatal("Permission denied (%s).", authlist);
339 authctxt->method = method;
341 /* reset the per method handler */
342 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
343 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
345 /* and try new method */
346 if (method->userauth(authctxt) != 0) {
347 debug2("we sent a %s packet, wait for reply", method->name);
350 debug2("we did not send a packet, disable method");
351 method->enabled = NULL;
357 input_userauth_error(int type, u_int32_t seq, void *ctxt)
359 fatal("input_userauth_error: bad message during authentication: "
364 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
368 debug3("input_userauth_banner");
369 msg = packet_get_string(NULL);
370 lang = packet_get_string(NULL);
371 if (options.log_level > SYSLOG_LEVEL_QUIET)
372 fprintf(stderr, "%s", msg);
378 input_userauth_success(int type, u_int32_t seq, void *ctxt)
380 Authctxt *authctxt = ctxt;
381 if (authctxt == NULL)
382 fatal("input_userauth_success: no authentication context");
383 if (authctxt->authlist) {
384 xfree(authctxt->authlist);
385 authctxt->authlist = NULL;
387 if (authctxt->methoddata) {
388 xfree(authctxt->methoddata);
389 authctxt->methoddata = NULL;
391 authctxt->success = 1; /* break out */
395 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
397 Authctxt *authctxt = ctxt;
398 char *authlist = NULL;
401 if (authctxt == NULL)
402 fatal("input_userauth_failure: no authentication context");
404 authlist = packet_get_string(NULL);
405 partial = packet_get_char();
409 logit("Authenticated with partial success.");
410 debug("Authentications that can continue: %s", authlist);
412 userauth(authctxt, authlist);
415 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
417 Authctxt *authctxt = ctxt;
421 int pktype, sent = 0;
426 if (authctxt == NULL)
427 fatal("input_userauth_pk_ok: no authentication context");
428 if (datafellows & SSH_BUG_PKOK) {
429 /* this is similar to SSH_BUG_PKAUTH */
430 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
431 pkblob = packet_get_string(&blen);
433 buffer_append(&b, pkblob, blen);
434 pkalg = buffer_get_string(&b, &alen);
437 pkalg = packet_get_string(&alen);
438 pkblob = packet_get_string(&blen);
442 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
444 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
445 debug("unknown pkalg %s", pkalg);
448 if ((key = key_from_blob(pkblob, blen)) == NULL) {
449 debug("no key from blob. pkalg %s", pkalg);
452 if (key->type != pktype) {
453 error("input_userauth_pk_ok: type mismatch "
454 "for decoded key (received %d, expected %d)",
458 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
459 debug2("input_userauth_pk_ok: fp %s", fp);
463 * search keys in the reverse order, because last candidate has been
464 * moved to the end of the queue. this also avoids confusion by
467 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
468 if (key_equal(key, id->key)) {
469 sent = sign_and_send_pubkey(authctxt, id);
479 /* try another method if we did not send a packet */
481 userauth(authctxt, NULL);
486 userauth_gssapi(Authctxt *authctxt)
488 Gssctxt *gssctxt = NULL;
489 static gss_OID_set gss_supported = NULL;
490 static u_int mech = 0;
494 /* Try one GSSAPI method at a time, rather than sending them all at
497 if (gss_supported == NULL)
498 gss_indicate_mechs(&min, &gss_supported);
500 /* Check to see if the mechanism is usable before we offer it */
501 while (mech < gss_supported->count && !ok) {
503 ssh_gssapi_delete_ctx(&gssctxt);
504 ssh_gssapi_build_ctx(&gssctxt);
505 ssh_gssapi_set_oid(gssctxt, &gss_supported->elements[mech]);
507 /* My DER encoding requires length<128 */
508 if (gss_supported->elements[mech].length < 128 &&
509 !GSS_ERROR(ssh_gssapi_import_name(gssctxt,
511 ok = 1; /* Mechanism works */
520 authctxt->methoddata=(void *)gssctxt;
522 packet_start(SSH2_MSG_USERAUTH_REQUEST);
523 packet_put_cstring(authctxt->server_user);
524 packet_put_cstring(authctxt->service);
525 packet_put_cstring(authctxt->method->name);
529 packet_put_int((gss_supported->elements[mech].length) + 2);
530 packet_put_char(SSH_GSS_OIDTYPE);
531 packet_put_char(gss_supported->elements[mech].length);
532 packet_put_raw(gss_supported->elements[mech].elements,
533 gss_supported->elements[mech].length);
537 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
538 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
539 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
540 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
542 mech++; /* Move along to next candidate */
548 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
550 Authctxt *authctxt = ctxt;
551 Gssctxt *gssctxt = authctxt->methoddata;
552 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
553 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
554 gss_buffer_desc gssbuf;
555 OM_uint32 status, ms, flags;
558 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
559 recv_tok, &send_tok, &flags);
561 if (send_tok.length > 0) {
562 if (GSS_ERROR(status))
563 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
565 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
567 packet_put_string(send_tok.value, send_tok.length);
569 gss_release_buffer(&ms, &send_tok);
572 if (status == GSS_S_COMPLETE) {
573 /* send either complete or MIC, depending on mechanism */
574 if (!(flags & GSS_C_INTEG_FLAG)) {
575 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
578 ssh_gssapi_buildmic(&b, authctxt->server_user,
579 authctxt->service, "gssapi-with-mic");
581 gssbuf.value = buffer_ptr(&b);
582 gssbuf.length = buffer_len(&b);
584 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
586 if (!GSS_ERROR(status)) {
587 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
588 packet_put_string(mic.value, mic.length);
594 gss_release_buffer(&ms, &mic);
602 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
604 Authctxt *authctxt = ctxt;
609 if (authctxt == NULL)
610 fatal("input_gssapi_response: no authentication context");
611 gssctxt = authctxt->methoddata;
614 oidv = packet_get_string(&oidlen);
617 oidv[0] != SSH_GSS_OIDTYPE ||
618 oidv[1] != oidlen - 2) {
620 debug("Badly encoded mechanism OID received");
621 userauth(authctxt, NULL);
625 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
626 fatal("Server returned different OID than expected");
632 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
633 /* Start again with next method on list */
634 debug("Trying to start again");
635 userauth(authctxt, NULL);
641 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
643 Authctxt *authctxt = ctxt;
644 gss_buffer_desc recv_tok;
648 if (authctxt == NULL)
649 fatal("input_gssapi_response: no authentication context");
651 recv_tok.value = packet_get_string(&slen);
652 recv_tok.length = slen; /* safe typecast */
656 status = process_gssapi_token(ctxt, &recv_tok);
658 xfree(recv_tok.value);
660 if (GSS_ERROR(status)) {
661 /* Start again with the next method in the list */
662 userauth(authctxt, NULL);
668 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
670 Authctxt *authctxt = ctxt;
672 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
673 gss_buffer_desc recv_tok;
674 OM_uint32 status, ms;
677 if (authctxt == NULL)
678 fatal("input_gssapi_response: no authentication context");
679 gssctxt = authctxt->methoddata;
681 recv_tok.value = packet_get_string(&len);
682 recv_tok.length = len;
686 /* Stick it into GSSAPI and see what it says */
687 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
688 &recv_tok, &send_tok, NULL);
690 xfree(recv_tok.value);
691 gss_release_buffer(&ms, &send_tok);
693 /* Server will be returning a failed packet after this one */
697 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
703 maj=packet_get_int();
704 min=packet_get_int();
705 msg=packet_get_string(NULL);
706 lang=packet_get_string(NULL);
710 debug("Server GSSAPI Error:\n%s", msg);
717 userauth_none(Authctxt *authctxt)
719 /* initial userauth request */
720 packet_start(SSH2_MSG_USERAUTH_REQUEST);
721 packet_put_cstring(authctxt->server_user);
722 packet_put_cstring(authctxt->service);
723 packet_put_cstring(authctxt->method->name);
729 userauth_passwd(Authctxt *authctxt)
731 static int attempt = 0;
735 if (attempt++ >= options.number_of_password_prompts)
739 error("Permission denied, please try again.");
741 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
742 authctxt->server_user, authctxt->host);
743 password = read_passphrase(prompt, 0);
744 packet_start(SSH2_MSG_USERAUTH_REQUEST);
745 packet_put_cstring(authctxt->server_user);
746 packet_put_cstring(authctxt->service);
747 packet_put_cstring(authctxt->method->name);
749 packet_put_cstring(password);
750 memset(password, 0, strlen(password));
752 packet_add_padding(64);
755 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
756 &input_userauth_passwd_changereq);
761 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
764 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
766 Authctxt *authctxt = ctxt;
767 char *info, *lang, *password = NULL, *retype = NULL;
770 debug2("input_userauth_passwd_changereq");
772 if (authctxt == NULL)
773 fatal("input_userauth_passwd_changereq: "
774 "no authentication context");
776 info = packet_get_string(NULL);
777 lang = packet_get_string(NULL);
778 if (strlen(info) > 0)
782 packet_start(SSH2_MSG_USERAUTH_REQUEST);
783 packet_put_cstring(authctxt->server_user);
784 packet_put_cstring(authctxt->service);
785 packet_put_cstring(authctxt->method->name);
786 packet_put_char(1); /* additional info */
787 snprintf(prompt, sizeof(prompt),
788 "Enter %.30s@%.128s's old password: ",
789 authctxt->server_user, authctxt->host);
790 password = read_passphrase(prompt, 0);
791 packet_put_cstring(password);
792 memset(password, 0, strlen(password));
795 while (password == NULL) {
796 snprintf(prompt, sizeof(prompt),
797 "Enter %.30s@%.128s's new password: ",
798 authctxt->server_user, authctxt->host);
799 password = read_passphrase(prompt, RP_ALLOW_EOF);
800 if (password == NULL) {
804 snprintf(prompt, sizeof(prompt),
805 "Retype %.30s@%.128s's new password: ",
806 authctxt->server_user, authctxt->host);
807 retype = read_passphrase(prompt, 0);
808 if (strcmp(password, retype) != 0) {
809 memset(password, 0, strlen(password));
811 logit("Mismatch; try again, EOF to quit.");
814 memset(retype, 0, strlen(retype));
817 packet_put_cstring(password);
818 memset(password, 0, strlen(password));
820 packet_add_padding(64);
823 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
824 &input_userauth_passwd_changereq);
828 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
829 u_char *data, u_int datalen)
834 /* the agent supports this key */
836 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
839 * we have already loaded the private key or
840 * the private key is stored in external hardware
842 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
843 return (key_sign(id->key, sigp, lenp, data, datalen));
844 /* load the private key from the file */
845 if ((prv = load_identity_file(id->filename)) == NULL)
847 ret = key_sign(prv, sigp, lenp, data, datalen);
853 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
856 u_char *blob, *signature;
862 debug3("sign_and_send_pubkey");
864 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
865 /* we cannot handle this key */
866 debug3("sign_and_send_pubkey: cannot handle key");
869 /* data to be signed */
871 if (datafellows & SSH_OLD_SESSIONID) {
872 buffer_append(&b, session_id2, session_id2_len);
873 skip = session_id2_len;
875 buffer_put_string(&b, session_id2, session_id2_len);
876 skip = buffer_len(&b);
878 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
879 buffer_put_cstring(&b, authctxt->server_user);
880 buffer_put_cstring(&b,
881 datafellows & SSH_BUG_PKSERVICE ?
884 if (datafellows & SSH_BUG_PKAUTH) {
885 buffer_put_char(&b, have_sig);
887 buffer_put_cstring(&b, authctxt->method->name);
888 buffer_put_char(&b, have_sig);
889 buffer_put_cstring(&b, key_ssh_name(id->key));
891 buffer_put_string(&b, blob, bloblen);
893 /* generate signature */
894 ret = identity_sign(id, &signature, &slen,
895 buffer_ptr(&b), buffer_len(&b));
904 if (datafellows & SSH_BUG_PKSERVICE) {
906 buffer_append(&b, session_id2, session_id2_len);
907 skip = session_id2_len;
908 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
909 buffer_put_cstring(&b, authctxt->server_user);
910 buffer_put_cstring(&b, authctxt->service);
911 buffer_put_cstring(&b, authctxt->method->name);
912 buffer_put_char(&b, have_sig);
913 if (!(datafellows & SSH_BUG_PKAUTH))
914 buffer_put_cstring(&b, key_ssh_name(id->key));
915 buffer_put_string(&b, blob, bloblen);
919 /* append signature */
920 buffer_put_string(&b, signature, slen);
923 /* skip session id and packet type */
924 if (buffer_len(&b) < skip + 1)
925 fatal("userauth_pubkey: internal error");
926 buffer_consume(&b, skip + 1);
928 /* put remaining data from buffer into packet */
929 packet_start(SSH2_MSG_USERAUTH_REQUEST);
930 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
938 send_pubkey_test(Authctxt *authctxt, Identity *id)
941 u_int bloblen, have_sig = 0;
943 debug3("send_pubkey_test");
945 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
946 /* we cannot handle this key */
947 debug3("send_pubkey_test: cannot handle key");
950 /* register callback for USERAUTH_PK_OK message */
951 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
953 packet_start(SSH2_MSG_USERAUTH_REQUEST);
954 packet_put_cstring(authctxt->server_user);
955 packet_put_cstring(authctxt->service);
956 packet_put_cstring(authctxt->method->name);
957 packet_put_char(have_sig);
958 if (!(datafellows & SSH_BUG_PKAUTH))
959 packet_put_cstring(key_ssh_name(id->key));
960 packet_put_string(blob, bloblen);
967 load_identity_file(char *filename)
970 char prompt[300], *passphrase;
974 if (stat(filename, &st) < 0) {
975 debug3("no such identity: %s", filename);
978 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
979 if (private == NULL) {
980 if (options.batch_mode)
982 snprintf(prompt, sizeof prompt,
983 "Enter passphrase for key '%.100s': ", filename);
984 for (i = 0; i < options.number_of_password_prompts; i++) {
985 passphrase = read_passphrase(prompt, 0);
986 if (strcmp(passphrase, "") != 0) {
987 private = key_load_private_type(KEY_UNSPEC, filename,
991 debug2("no passphrase given, try next key");
994 memset(passphrase, 0, strlen(passphrase));
996 if (private != NULL || quit)
998 debug2("bad passphrase given, try again...");
1005 * try keys in the following order:
1006 * 1. agent keys that are found in the config file
1007 * 2. other agent keys
1008 * 3. keys that are only listed in the config file
1011 pubkey_prepare(Authctxt *authctxt)
1014 Idlist agent, files, *preferred;
1016 AuthenticationConnection *ac;
1020 TAILQ_INIT(&agent); /* keys from the agent */
1021 TAILQ_INIT(&files); /* keys from the config file */
1022 preferred = &authctxt->keys;
1023 TAILQ_INIT(preferred); /* preferred order of keys */
1025 /* list of keys stored in the filesystem */
1026 for (i = 0; i < options.num_identity_files; i++) {
1027 key = options.identity_keys[i];
1028 if (key && key->type == KEY_RSA1)
1030 options.identity_keys[i] = NULL;
1031 id = xmalloc(sizeof(*id));
1032 memset(id, 0, sizeof(*id));
1034 id->filename = xstrdup(options.identity_files[i]);
1035 TAILQ_INSERT_TAIL(&files, id, next);
1037 /* list of keys supported by the agent */
1038 if ((ac = ssh_get_authentication_connection())) {
1039 for (key = ssh_get_first_identity(ac, &comment, 2);
1041 key = ssh_get_next_identity(ac, &comment, 2)) {
1043 TAILQ_FOREACH(id, &files, next) {
1044 /* agent keys from the config file are preferred */
1045 if (key_equal(key, id->key)) {
1048 TAILQ_REMOVE(&files, id, next);
1049 TAILQ_INSERT_TAIL(preferred, id, next);
1055 if (!found && !options.identities_only) {
1056 id = xmalloc(sizeof(*id));
1057 memset(id, 0, sizeof(*id));
1059 id->filename = comment;
1061 TAILQ_INSERT_TAIL(&agent, id, next);
1064 /* append remaining agent keys */
1065 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1066 TAILQ_REMOVE(&agent, id, next);
1067 TAILQ_INSERT_TAIL(preferred, id, next);
1069 authctxt->agent = ac;
1071 /* append remaining keys from the config file */
1072 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1073 TAILQ_REMOVE(&files, id, next);
1074 TAILQ_INSERT_TAIL(preferred, id, next);
1076 TAILQ_FOREACH(id, preferred, next) {
1077 debug2("key: %s (%p)", id->filename, id->key);
1082 pubkey_cleanup(Authctxt *authctxt)
1086 if (authctxt->agent != NULL)
1087 ssh_close_authentication_connection(authctxt->agent);
1088 for (id = TAILQ_FIRST(&authctxt->keys); id;
1089 id = TAILQ_FIRST(&authctxt->keys)) {
1090 TAILQ_REMOVE(&authctxt->keys, id, next);
1094 xfree(id->filename);
1100 userauth_pubkey(Authctxt *authctxt)
1105 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1108 /* move key to the end of the queue */
1109 TAILQ_REMOVE(&authctxt->keys, id, next);
1110 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1112 * send a test message if we have the public key. for
1113 * encrypted keys we cannot do this and have to load the
1114 * private key instead
1116 if (id->key && id->key->type != KEY_RSA1) {
1117 debug("Offering public key: %s", id->filename);
1118 sent = send_pubkey_test(authctxt, id);
1119 } else if (id->key == NULL) {
1120 debug("Trying private key: %s", id->filename);
1121 id->key = load_identity_file(id->filename);
1122 if (id->key != NULL) {
1124 sent = sign_and_send_pubkey(authctxt, id);
1136 * Send userauth request message specifying keyboard-interactive method.
1139 userauth_kbdint(Authctxt *authctxt)
1141 static int attempt = 0;
1143 if (attempt++ >= options.number_of_password_prompts)
1145 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1146 if (attempt > 1 && !authctxt->info_req_seen) {
1147 debug3("userauth_kbdint: disable: no info_req_seen");
1148 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1152 debug2("userauth_kbdint");
1153 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1154 packet_put_cstring(authctxt->server_user);
1155 packet_put_cstring(authctxt->service);
1156 packet_put_cstring(authctxt->method->name);
1157 packet_put_cstring(""); /* lang */
1158 packet_put_cstring(options.kbd_interactive_devices ?
1159 options.kbd_interactive_devices : "");
1162 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1167 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1170 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1172 Authctxt *authctxt = ctxt;
1173 char *name, *inst, *lang, *prompt, *response;
1174 u_int num_prompts, i;
1177 debug2("input_userauth_info_req");
1179 if (authctxt == NULL)
1180 fatal("input_userauth_info_req: no authentication context");
1182 authctxt->info_req_seen = 1;
1184 name = packet_get_string(NULL);
1185 inst = packet_get_string(NULL);
1186 lang = packet_get_string(NULL);
1187 if (strlen(name) > 0)
1189 if (strlen(inst) > 0)
1195 num_prompts = packet_get_int();
1197 * Begin to build info response packet based on prompts requested.
1198 * We commit to providing the correct number of responses, so if
1199 * further on we run into a problem that prevents this, we have to
1200 * be sure and clean this up and send a correct error response.
1202 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1203 packet_put_int(num_prompts);
1205 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1206 for (i = 0; i < num_prompts; i++) {
1207 prompt = packet_get_string(NULL);
1208 echo = packet_get_char();
1210 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1212 packet_put_cstring(response);
1213 memset(response, 0, strlen(response));
1217 packet_check_eom(); /* done with parsing incoming message. */
1219 packet_add_padding(64);
1224 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1225 u_char *data, u_int datalen)
1230 int to[2], from[2], status, version = 2;
1232 debug2("ssh_keysign called");
1234 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1235 error("ssh_keysign: no installed: %s", strerror(errno));
1238 if (fflush(stdout) != 0)
1239 error("ssh_keysign: fflush: %s", strerror(errno));
1241 error("ssh_keysign: pipe: %s", strerror(errno));
1244 if (pipe(from) < 0) {
1245 error("ssh_keysign: pipe: %s", strerror(errno));
1248 if ((pid = fork()) < 0) {
1249 error("ssh_keysign: fork: %s", strerror(errno));
1256 if (dup2(from[1], STDOUT_FILENO) < 0)
1257 fatal("ssh_keysign: dup2: %s", strerror(errno));
1259 if (dup2(to[0], STDIN_FILENO) < 0)
1260 fatal("ssh_keysign: dup2: %s", strerror(errno));
1263 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1264 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1271 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1272 buffer_put_string(&b, data, datalen);
1273 if (ssh_msg_send(to[1], version, &b) == -1)
1274 fatal("ssh_keysign: couldn't send request");
1276 if (ssh_msg_recv(from[0], &b) < 0) {
1277 error("ssh_keysign: no reply");
1284 while (waitpid(pid, &status, 0) < 0)
1288 if (buffer_get_char(&b) != version) {
1289 error("ssh_keysign: bad version");
1293 *sigp = buffer_get_string(&b, lenp);
1300 userauth_hostbased(Authctxt *authctxt)
1302 Key *private = NULL;
1303 Sensitive *sensitive = authctxt->sensitive;
1305 u_char *signature, *blob;
1306 char *chost, *pkalg, *p;
1307 const char *service;
1309 int ok, i, len, found = 0;
1311 /* check for a useful key */
1312 for (i = 0; i < sensitive->nkeys; i++) {
1313 private = sensitive->keys[i];
1314 if (private && private->type != KEY_RSA1) {
1316 /* we take and free the key */
1317 sensitive->keys[i] = NULL;
1322 debug("No more client hostkeys for hostbased authentication.");
1325 if (key_to_blob(private, &blob, &blen) == 0) {
1329 /* figure out a name for the client host */
1330 p = get_local_name(packet_get_connection_in());
1332 error("userauth_hostbased: cannot get local ipaddr/name");
1336 len = strlen(p) + 2;
1337 chost = xmalloc(len);
1338 strlcpy(chost, p, len);
1339 strlcat(chost, ".", len);
1340 debug2("userauth_hostbased: chost %s", chost);
1343 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1345 pkalg = xstrdup(key_ssh_name(private));
1347 /* construct data */
1348 buffer_put_string(&b, session_id2, session_id2_len);
1349 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1350 buffer_put_cstring(&b, authctxt->server_user);
1351 buffer_put_cstring(&b, service);
1352 buffer_put_cstring(&b, authctxt->method->name);
1353 buffer_put_cstring(&b, pkalg);
1354 buffer_put_string(&b, blob, blen);
1355 buffer_put_cstring(&b, chost);
1356 buffer_put_cstring(&b, authctxt->local_user);
1360 if (sensitive->external_keysign)
1361 ok = ssh_keysign(private, &signature, &slen,
1362 buffer_ptr(&b), buffer_len(&b));
1364 ok = key_sign(private, &signature, &slen,
1365 buffer_ptr(&b), buffer_len(&b));
1369 error("key_sign failed");
1374 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1375 packet_put_cstring(authctxt->server_user);
1376 packet_put_cstring(authctxt->service);
1377 packet_put_cstring(authctxt->method->name);
1378 packet_put_cstring(pkalg);
1379 packet_put_string(blob, blen);
1380 packet_put_cstring(chost);
1381 packet_put_cstring(authctxt->local_user);
1382 packet_put_string(signature, slen);
1383 memset(signature, 's', slen);
1392 /* find auth method */
1395 * given auth method name, if configurable options permit this method fill
1396 * in auth_ident field and return true, otherwise return false.
1399 authmethod_is_enabled(Authmethod *method)
1403 /* return false if options indicate this method is disabled */
1404 if (method->enabled == NULL || *method->enabled == 0)
1406 /* return false if batch mode is enabled but method needs interactive mode */
1407 if (method->batch_flag != NULL && *method->batch_flag != 0)
1413 authmethod_lookup(const char *name)
1415 Authmethod *method = NULL;
1417 for (method = authmethods; method->name != NULL; method++)
1418 if (strcmp(name, method->name) == 0)
1420 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1424 /* XXX internal state */
1425 static Authmethod *current = NULL;
1426 static char *supported = NULL;
1427 static char *preferred = NULL;
1430 * Given the authentication method list sent by the server, return the
1431 * next method we should try. If the server initially sends a nil list,
1432 * use a built-in default list.
1435 authmethod_get(char *authlist)
1440 /* Use a suitable default if we're passed a nil list. */
1441 if (authlist == NULL || strlen(authlist) == 0)
1442 authlist = options.preferred_authentications;
1444 if (supported == NULL || strcmp(authlist, supported) != 0) {
1445 debug3("start over, passed a different list %s", authlist);
1446 if (supported != NULL)
1448 supported = xstrdup(authlist);
1449 preferred = options.preferred_authentications;
1450 debug3("preferred %s", preferred);
1452 } else if (current != NULL && authmethod_is_enabled(current))
1456 if ((name = match_list(preferred, supported, &next)) == NULL) {
1457 debug("No more authentication methods to try.");
1462 debug3("authmethod_lookup %s", name);
1463 debug3("remaining preferred: %s", preferred);
1464 if ((current = authmethod_lookup(name)) != NULL &&
1465 authmethod_is_enabled(current)) {
1466 debug3("authmethod_is_enabled %s", name);
1467 debug("Next authentication method: %s", name);
1474 authmethods_get(void)
1476 Authmethod *method = NULL;
1481 for (method = authmethods; method->name != NULL; method++) {
1482 if (authmethod_is_enabled(method)) {
1483 if (buffer_len(&b) > 0)
1484 buffer_append(&b, ",", 1);
1485 buffer_append(&b, method->name, strlen(method->name));
1488 buffer_append(&b, "\0", 1);
1489 list = xstrdup(buffer_ptr(&b));