1 /* $OpenBSD: sshconnect2.c,v 1.162 2006/08/30 00:06:51 dtucker 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>
40 #include "openbsd-compat/sys-queue.h"
51 #include "myproposal.h"
52 #include "sshconnect.h"
63 #include "pathnames.h"
71 extern char *client_version_string;
72 extern char *server_version_string;
73 extern Options options;
79 u_char *session_id2 = NULL;
80 u_int session_id2_len = 0;
83 struct sockaddr *xxx_hostaddr;
88 verify_host_key_callback(Key *hostkey)
90 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
91 fatal("Host key verification failed.");
96 ssh_kex2(char *host, struct sockaddr *hostaddr)
101 xxx_hostaddr = hostaddr;
103 if (options.ciphers == (char *)-1) {
104 logit("No valid ciphers for protocol version 2 given, using defaults.");
105 options.ciphers = NULL;
107 if (options.ciphers != NULL) {
108 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
109 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
111 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
112 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
113 myproposal[PROPOSAL_ENC_ALGS_STOC] =
114 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
115 if (options.compression) {
116 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
117 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
119 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
120 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
122 if (options.macs != NULL) {
123 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
124 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
126 if (options.hostkeyalgorithms != NULL)
127 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
128 options.hostkeyalgorithms;
130 if (options.rekey_limit)
131 packet_set_rekey_limit(options.rekey_limit);
133 /* start key exchange */
134 kex = kex_setup(myproposal);
135 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
136 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
137 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
138 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
139 kex->client_version_string=client_version_string;
140 kex->server_version_string=server_version_string;
141 kex->verify_host_key=&verify_host_key_callback;
145 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
147 session_id2 = kex->session_id;
148 session_id2_len = kex->session_id_len;
151 /* send 1st encrypted/maced/compressed message */
152 packet_start(SSH2_MSG_IGNORE);
153 packet_put_cstring("markus");
163 typedef struct Authctxt Authctxt;
164 typedef struct Authmethod Authmethod;
165 typedef struct identity Identity;
166 typedef struct idlist Idlist;
169 TAILQ_ENTRY(identity) next;
170 AuthenticationConnection *ac; /* set if agent supports key */
171 Key *key; /* public/private key */
172 char *filename; /* comment for agent-only keys */
174 int isprivate; /* key points to the private key */
176 TAILQ_HEAD(idlist, identity);
179 const char *server_user;
180 const char *local_user;
188 AuthenticationConnection *agent;
190 Sensitive *sensitive;
191 /* kbd-interactive */
197 char *name; /* string to compare against server's list */
198 int (*userauth)(Authctxt *authctxt);
199 int *enabled; /* flag in option struct that enables method */
200 int *batch_flag; /* flag in option struct that disables method */
203 void input_userauth_success(int, u_int32_t, void *);
204 void input_userauth_failure(int, u_int32_t, void *);
205 void input_userauth_banner(int, u_int32_t, void *);
206 void input_userauth_error(int, u_int32_t, void *);
207 void input_userauth_info_req(int, u_int32_t, void *);
208 void input_userauth_pk_ok(int, u_int32_t, void *);
209 void input_userauth_passwd_changereq(int, u_int32_t, void *);
211 int userauth_none(Authctxt *);
212 int userauth_pubkey(Authctxt *);
213 int userauth_passwd(Authctxt *);
214 int userauth_kbdint(Authctxt *);
215 int userauth_hostbased(Authctxt *);
216 int userauth_kerberos(Authctxt *);
219 int userauth_gssapi(Authctxt *authctxt);
220 void input_gssapi_response(int type, u_int32_t, void *);
221 void input_gssapi_token(int type, u_int32_t, void *);
222 void input_gssapi_hash(int type, u_int32_t, void *);
223 void input_gssapi_error(int, u_int32_t, void *);
224 void input_gssapi_errtok(int, u_int32_t, void *);
227 void userauth(Authctxt *, char *);
229 static int sign_and_send_pubkey(Authctxt *, Identity *);
230 static void pubkey_prepare(Authctxt *);
231 static void pubkey_cleanup(Authctxt *);
232 static Key *load_identity_file(char *);
234 static Authmethod *authmethod_get(char *authlist);
235 static Authmethod *authmethod_lookup(const char *name);
236 static char *authmethods_get(void);
238 Authmethod authmethods[] = {
242 &options.gss_authentication,
247 &options.hostbased_authentication,
251 &options.pubkey_authentication,
253 {"keyboard-interactive",
255 &options.kbd_interactive_authentication,
256 &options.batch_mode},
259 &options.password_authentication,
260 &options.batch_mode},
265 {NULL, NULL, NULL, NULL}
269 ssh_userauth2(const char *local_user, const char *server_user, char *host,
270 Sensitive *sensitive)
275 if (options.challenge_response_authentication)
276 options.kbd_interactive_authentication = 1;
278 packet_start(SSH2_MSG_SERVICE_REQUEST);
279 packet_put_cstring("ssh-userauth");
281 debug("SSH2_MSG_SERVICE_REQUEST sent");
283 type = packet_read();
284 if (type != SSH2_MSG_SERVICE_ACCEPT)
285 fatal("Server denied authentication request: %d", type);
286 if (packet_remaining() > 0) {
287 char *reply = packet_get_string(NULL);
288 debug2("service_accept: %s", reply);
291 debug2("buggy server: service_accept w/o service");
294 debug("SSH2_MSG_SERVICE_ACCEPT received");
296 if (options.preferred_authentications == NULL)
297 options.preferred_authentications = authmethods_get();
299 /* setup authentication context */
300 memset(&authctxt, 0, sizeof(authctxt));
301 pubkey_prepare(&authctxt);
302 authctxt.server_user = server_user;
303 authctxt.local_user = local_user;
304 authctxt.host = host;
305 authctxt.service = "ssh-connection"; /* service name */
306 authctxt.success = 0;
307 authctxt.method = authmethod_lookup("none");
308 authctxt.authlist = NULL;
309 authctxt.methoddata = NULL;
310 authctxt.sensitive = sensitive;
311 authctxt.info_req_seen = 0;
312 if (authctxt.method == NULL)
313 fatal("ssh_userauth2: internal error: cannot send userauth none request");
315 /* initial userauth request */
316 userauth_none(&authctxt);
318 dispatch_init(&input_userauth_error);
319 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
320 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
321 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
322 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
324 pubkey_cleanup(&authctxt);
325 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
327 debug("Authentication succeeded (%s).", authctxt.method->name);
331 userauth(Authctxt *authctxt, char *authlist)
333 if (authctxt->methoddata) {
334 xfree(authctxt->methoddata);
335 authctxt->methoddata = NULL;
337 if (authlist == NULL) {
338 authlist = authctxt->authlist;
340 if (authctxt->authlist)
341 xfree(authctxt->authlist);
342 authctxt->authlist = authlist;
345 Authmethod *method = authmethod_get(authlist);
347 fatal("Permission denied (%s).", authlist);
348 authctxt->method = method;
350 /* reset the per method handler */
351 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
352 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
354 /* and try new method */
355 if (method->userauth(authctxt) != 0) {
356 debug2("we sent a %s packet, wait for reply", method->name);
359 debug2("we did not send a packet, disable method");
360 method->enabled = NULL;
366 input_userauth_error(int type, u_int32_t seq, void *ctxt)
368 fatal("input_userauth_error: bad message during authentication: "
373 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
377 debug3("input_userauth_banner");
378 msg = packet_get_string(NULL);
379 lang = packet_get_string(NULL);
380 if (options.log_level >= SYSLOG_LEVEL_INFO)
381 fprintf(stderr, "%s", msg);
387 input_userauth_success(int type, u_int32_t seq, void *ctxt)
389 Authctxt *authctxt = ctxt;
390 if (authctxt == NULL)
391 fatal("input_userauth_success: no authentication context");
392 if (authctxt->authlist) {
393 xfree(authctxt->authlist);
394 authctxt->authlist = NULL;
396 if (authctxt->methoddata) {
397 xfree(authctxt->methoddata);
398 authctxt->methoddata = NULL;
400 authctxt->success = 1; /* break out */
404 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
406 Authctxt *authctxt = ctxt;
407 char *authlist = NULL;
410 if (authctxt == NULL)
411 fatal("input_userauth_failure: no authentication context");
413 authlist = packet_get_string(NULL);
414 partial = packet_get_char();
418 logit("Authenticated with partial success.");
419 debug("Authentications that can continue: %s", authlist);
421 userauth(authctxt, authlist);
424 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
426 Authctxt *authctxt = ctxt;
430 int pktype, sent = 0;
435 if (authctxt == NULL)
436 fatal("input_userauth_pk_ok: no authentication context");
437 if (datafellows & SSH_BUG_PKOK) {
438 /* this is similar to SSH_BUG_PKAUTH */
439 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
440 pkblob = packet_get_string(&blen);
442 buffer_append(&b, pkblob, blen);
443 pkalg = buffer_get_string(&b, &alen);
446 pkalg = packet_get_string(&alen);
447 pkblob = packet_get_string(&blen);
451 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
453 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
454 debug("unknown pkalg %s", pkalg);
457 if ((key = key_from_blob(pkblob, blen)) == NULL) {
458 debug("no key from blob. pkalg %s", pkalg);
461 if (key->type != pktype) {
462 error("input_userauth_pk_ok: type mismatch "
463 "for decoded key (received %d, expected %d)",
467 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
468 debug2("input_userauth_pk_ok: fp %s", fp);
472 * search keys in the reverse order, because last candidate has been
473 * moved to the end of the queue. this also avoids confusion by
476 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
477 if (key_equal(key, id->key)) {
478 sent = sign_and_send_pubkey(authctxt, id);
488 /* try another method if we did not send a packet */
490 userauth(authctxt, NULL);
495 userauth_gssapi(Authctxt *authctxt)
497 Gssctxt *gssctxt = NULL;
498 static gss_OID_set gss_supported = NULL;
499 static u_int mech = 0;
503 /* Try one GSSAPI method at a time, rather than sending them all at
506 if (gss_supported == NULL)
507 gss_indicate_mechs(&min, &gss_supported);
509 /* Check to see if the mechanism is usable before we offer it */
510 while (mech < gss_supported->count && !ok) {
511 /* My DER encoding requires length<128 */
512 if (gss_supported->elements[mech].length < 128 &&
513 ssh_gssapi_check_mechanism(&gssctxt,
514 &gss_supported->elements[mech], authctxt->host)) {
515 ok = 1; /* Mechanism works */
524 authctxt->methoddata=(void *)gssctxt;
526 packet_start(SSH2_MSG_USERAUTH_REQUEST);
527 packet_put_cstring(authctxt->server_user);
528 packet_put_cstring(authctxt->service);
529 packet_put_cstring(authctxt->method->name);
533 packet_put_int((gss_supported->elements[mech].length) + 2);
534 packet_put_char(SSH_GSS_OIDTYPE);
535 packet_put_char(gss_supported->elements[mech].length);
536 packet_put_raw(gss_supported->elements[mech].elements,
537 gss_supported->elements[mech].length);
541 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
542 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
543 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
544 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
546 mech++; /* Move along to next candidate */
552 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
554 Authctxt *authctxt = ctxt;
555 Gssctxt *gssctxt = authctxt->methoddata;
556 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
557 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
558 gss_buffer_desc gssbuf;
559 OM_uint32 status, ms, flags;
562 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
563 recv_tok, &send_tok, &flags);
565 if (send_tok.length > 0) {
566 if (GSS_ERROR(status))
567 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
569 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
571 packet_put_string(send_tok.value, send_tok.length);
573 gss_release_buffer(&ms, &send_tok);
576 if (status == GSS_S_COMPLETE) {
577 /* send either complete or MIC, depending on mechanism */
578 if (!(flags & GSS_C_INTEG_FLAG)) {
579 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
582 ssh_gssapi_buildmic(&b, authctxt->server_user,
583 authctxt->service, "gssapi-with-mic");
585 gssbuf.value = buffer_ptr(&b);
586 gssbuf.length = buffer_len(&b);
588 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
590 if (!GSS_ERROR(status)) {
591 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
592 packet_put_string(mic.value, mic.length);
598 gss_release_buffer(&ms, &mic);
606 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
608 Authctxt *authctxt = ctxt;
613 if (authctxt == NULL)
614 fatal("input_gssapi_response: no authentication context");
615 gssctxt = authctxt->methoddata;
618 oidv = packet_get_string(&oidlen);
621 oidv[0] != SSH_GSS_OIDTYPE ||
622 oidv[1] != oidlen - 2) {
624 debug("Badly encoded mechanism OID received");
625 userauth(authctxt, NULL);
629 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
630 fatal("Server returned different OID than expected");
636 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
637 /* Start again with next method on list */
638 debug("Trying to start again");
639 userauth(authctxt, NULL);
645 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
647 Authctxt *authctxt = ctxt;
648 gss_buffer_desc recv_tok;
652 if (authctxt == NULL)
653 fatal("input_gssapi_response: no authentication context");
655 recv_tok.value = packet_get_string(&slen);
656 recv_tok.length = slen; /* safe typecast */
660 status = process_gssapi_token(ctxt, &recv_tok);
662 xfree(recv_tok.value);
664 if (GSS_ERROR(status)) {
665 /* Start again with the next method in the list */
666 userauth(authctxt, NULL);
672 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
674 Authctxt *authctxt = ctxt;
676 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
677 gss_buffer_desc recv_tok;
678 OM_uint32 status, ms;
681 if (authctxt == NULL)
682 fatal("input_gssapi_response: no authentication context");
683 gssctxt = authctxt->methoddata;
685 recv_tok.value = packet_get_string(&len);
686 recv_tok.length = len;
690 /* Stick it into GSSAPI and see what it says */
691 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
692 &recv_tok, &send_tok, NULL);
694 xfree(recv_tok.value);
695 gss_release_buffer(&ms, &send_tok);
697 /* Server will be returning a failed packet after this one */
701 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
707 maj=packet_get_int();
708 min=packet_get_int();
709 msg=packet_get_string(NULL);
710 lang=packet_get_string(NULL);
714 debug("Server GSSAPI Error:\n%s", msg);
721 userauth_none(Authctxt *authctxt)
723 /* initial userauth request */
724 packet_start(SSH2_MSG_USERAUTH_REQUEST);
725 packet_put_cstring(authctxt->server_user);
726 packet_put_cstring(authctxt->service);
727 packet_put_cstring(authctxt->method->name);
733 userauth_passwd(Authctxt *authctxt)
735 static int attempt = 0;
739 if (attempt++ >= options.number_of_password_prompts)
743 error("Permission denied, please try again.");
745 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
746 authctxt->server_user, authctxt->host);
747 password = read_passphrase(prompt, 0);
748 packet_start(SSH2_MSG_USERAUTH_REQUEST);
749 packet_put_cstring(authctxt->server_user);
750 packet_put_cstring(authctxt->service);
751 packet_put_cstring(authctxt->method->name);
753 packet_put_cstring(password);
754 memset(password, 0, strlen(password));
756 packet_add_padding(64);
759 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
760 &input_userauth_passwd_changereq);
765 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
768 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
770 Authctxt *authctxt = ctxt;
771 char *info, *lang, *password = NULL, *retype = NULL;
774 debug2("input_userauth_passwd_changereq");
776 if (authctxt == NULL)
777 fatal("input_userauth_passwd_changereq: "
778 "no authentication context");
780 info = packet_get_string(NULL);
781 lang = packet_get_string(NULL);
782 if (strlen(info) > 0)
786 packet_start(SSH2_MSG_USERAUTH_REQUEST);
787 packet_put_cstring(authctxt->server_user);
788 packet_put_cstring(authctxt->service);
789 packet_put_cstring(authctxt->method->name);
790 packet_put_char(1); /* additional info */
791 snprintf(prompt, sizeof(prompt),
792 "Enter %.30s@%.128s's old password: ",
793 authctxt->server_user, authctxt->host);
794 password = read_passphrase(prompt, 0);
795 packet_put_cstring(password);
796 memset(password, 0, strlen(password));
799 while (password == NULL) {
800 snprintf(prompt, sizeof(prompt),
801 "Enter %.30s@%.128s's new password: ",
802 authctxt->server_user, authctxt->host);
803 password = read_passphrase(prompt, RP_ALLOW_EOF);
804 if (password == NULL) {
808 snprintf(prompt, sizeof(prompt),
809 "Retype %.30s@%.128s's new password: ",
810 authctxt->server_user, authctxt->host);
811 retype = read_passphrase(prompt, 0);
812 if (strcmp(password, retype) != 0) {
813 memset(password, 0, strlen(password));
815 logit("Mismatch; try again, EOF to quit.");
818 memset(retype, 0, strlen(retype));
821 packet_put_cstring(password);
822 memset(password, 0, strlen(password));
824 packet_add_padding(64);
827 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
828 &input_userauth_passwd_changereq);
832 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
833 u_char *data, u_int datalen)
838 /* the agent supports this key */
840 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
843 * we have already loaded the private key or
844 * the private key is stored in external hardware
846 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
847 return (key_sign(id->key, sigp, lenp, data, datalen));
848 /* load the private key from the file */
849 if ((prv = load_identity_file(id->filename)) == NULL)
851 ret = key_sign(prv, sigp, lenp, data, datalen);
857 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
860 u_char *blob, *signature;
866 debug3("sign_and_send_pubkey");
868 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
869 /* we cannot handle this key */
870 debug3("sign_and_send_pubkey: cannot handle key");
873 /* data to be signed */
875 if (datafellows & SSH_OLD_SESSIONID) {
876 buffer_append(&b, session_id2, session_id2_len);
877 skip = session_id2_len;
879 buffer_put_string(&b, session_id2, session_id2_len);
880 skip = buffer_len(&b);
882 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
883 buffer_put_cstring(&b, authctxt->server_user);
884 buffer_put_cstring(&b,
885 datafellows & SSH_BUG_PKSERVICE ?
888 if (datafellows & SSH_BUG_PKAUTH) {
889 buffer_put_char(&b, have_sig);
891 buffer_put_cstring(&b, authctxt->method->name);
892 buffer_put_char(&b, have_sig);
893 buffer_put_cstring(&b, key_ssh_name(id->key));
895 buffer_put_string(&b, blob, bloblen);
897 /* generate signature */
898 ret = identity_sign(id, &signature, &slen,
899 buffer_ptr(&b), buffer_len(&b));
908 if (datafellows & SSH_BUG_PKSERVICE) {
910 buffer_append(&b, session_id2, session_id2_len);
911 skip = session_id2_len;
912 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
913 buffer_put_cstring(&b, authctxt->server_user);
914 buffer_put_cstring(&b, authctxt->service);
915 buffer_put_cstring(&b, authctxt->method->name);
916 buffer_put_char(&b, have_sig);
917 if (!(datafellows & SSH_BUG_PKAUTH))
918 buffer_put_cstring(&b, key_ssh_name(id->key));
919 buffer_put_string(&b, blob, bloblen);
923 /* append signature */
924 buffer_put_string(&b, signature, slen);
927 /* skip session id and packet type */
928 if (buffer_len(&b) < skip + 1)
929 fatal("userauth_pubkey: internal error");
930 buffer_consume(&b, skip + 1);
932 /* put remaining data from buffer into packet */
933 packet_start(SSH2_MSG_USERAUTH_REQUEST);
934 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
942 send_pubkey_test(Authctxt *authctxt, Identity *id)
945 u_int bloblen, have_sig = 0;
947 debug3("send_pubkey_test");
949 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
950 /* we cannot handle this key */
951 debug3("send_pubkey_test: cannot handle key");
954 /* register callback for USERAUTH_PK_OK message */
955 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
957 packet_start(SSH2_MSG_USERAUTH_REQUEST);
958 packet_put_cstring(authctxt->server_user);
959 packet_put_cstring(authctxt->service);
960 packet_put_cstring(authctxt->method->name);
961 packet_put_char(have_sig);
962 if (!(datafellows & SSH_BUG_PKAUTH))
963 packet_put_cstring(key_ssh_name(id->key));
964 packet_put_string(blob, bloblen);
971 load_identity_file(char *filename)
974 char prompt[300], *passphrase;
975 int perm_ok, quit, i;
978 if (stat(filename, &st) < 0) {
979 debug3("no such identity: %s", filename);
982 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
985 if (private == NULL) {
986 if (options.batch_mode)
988 snprintf(prompt, sizeof prompt,
989 "Enter passphrase for key '%.100s': ", filename);
990 for (i = 0; i < options.number_of_password_prompts; i++) {
991 passphrase = read_passphrase(prompt, 0);
992 if (strcmp(passphrase, "") != 0) {
993 private = key_load_private_type(KEY_UNSPEC,
994 filename, passphrase, NULL, NULL);
997 debug2("no passphrase given, try next key");
1000 memset(passphrase, 0, strlen(passphrase));
1002 if (private != NULL || quit)
1004 debug2("bad passphrase given, try again...");
1011 * try keys in the following order:
1012 * 1. agent keys that are found in the config file
1013 * 2. other agent keys
1014 * 3. keys that are only listed in the config file
1017 pubkey_prepare(Authctxt *authctxt)
1020 Idlist agent, files, *preferred;
1022 AuthenticationConnection *ac;
1026 TAILQ_INIT(&agent); /* keys from the agent */
1027 TAILQ_INIT(&files); /* keys from the config file */
1028 preferred = &authctxt->keys;
1029 TAILQ_INIT(preferred); /* preferred order of keys */
1031 /* list of keys stored in the filesystem */
1032 for (i = 0; i < options.num_identity_files; i++) {
1033 key = options.identity_keys[i];
1034 if (key && key->type == KEY_RSA1)
1036 options.identity_keys[i] = NULL;
1037 id = xcalloc(1, sizeof(*id));
1039 id->filename = xstrdup(options.identity_files[i]);
1040 TAILQ_INSERT_TAIL(&files, id, next);
1042 /* list of keys supported by the agent */
1043 if ((ac = ssh_get_authentication_connection())) {
1044 for (key = ssh_get_first_identity(ac, &comment, 2);
1046 key = ssh_get_next_identity(ac, &comment, 2)) {
1048 TAILQ_FOREACH(id, &files, next) {
1049 /* agent keys from the config file are preferred */
1050 if (key_equal(key, id->key)) {
1053 TAILQ_REMOVE(&files, id, next);
1054 TAILQ_INSERT_TAIL(preferred, id, next);
1060 if (!found && !options.identities_only) {
1061 id = xcalloc(1, sizeof(*id));
1063 id->filename = comment;
1065 TAILQ_INSERT_TAIL(&agent, id, next);
1068 /* append remaining agent keys */
1069 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1070 TAILQ_REMOVE(&agent, id, next);
1071 TAILQ_INSERT_TAIL(preferred, id, next);
1073 authctxt->agent = ac;
1075 /* append remaining keys from the config file */
1076 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1077 TAILQ_REMOVE(&files, id, next);
1078 TAILQ_INSERT_TAIL(preferred, id, next);
1080 TAILQ_FOREACH(id, preferred, next) {
1081 debug2("key: %s (%p)", id->filename, id->key);
1086 pubkey_cleanup(Authctxt *authctxt)
1090 if (authctxt->agent != NULL)
1091 ssh_close_authentication_connection(authctxt->agent);
1092 for (id = TAILQ_FIRST(&authctxt->keys); id;
1093 id = TAILQ_FIRST(&authctxt->keys)) {
1094 TAILQ_REMOVE(&authctxt->keys, id, next);
1098 xfree(id->filename);
1104 userauth_pubkey(Authctxt *authctxt)
1109 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1112 /* move key to the end of the queue */
1113 TAILQ_REMOVE(&authctxt->keys, id, next);
1114 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1116 * send a test message if we have the public key. for
1117 * encrypted keys we cannot do this and have to load the
1118 * private key instead
1120 if (id->key && id->key->type != KEY_RSA1) {
1121 debug("Offering public key: %s", id->filename);
1122 sent = send_pubkey_test(authctxt, id);
1123 } else if (id->key == NULL) {
1124 debug("Trying private key: %s", id->filename);
1125 id->key = load_identity_file(id->filename);
1126 if (id->key != NULL) {
1128 sent = sign_and_send_pubkey(authctxt, id);
1140 * Send userauth request message specifying keyboard-interactive method.
1143 userauth_kbdint(Authctxt *authctxt)
1145 static int attempt = 0;
1147 if (attempt++ >= options.number_of_password_prompts)
1149 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1150 if (attempt > 1 && !authctxt->info_req_seen) {
1151 debug3("userauth_kbdint: disable: no info_req_seen");
1152 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1156 debug2("userauth_kbdint");
1157 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1158 packet_put_cstring(authctxt->server_user);
1159 packet_put_cstring(authctxt->service);
1160 packet_put_cstring(authctxt->method->name);
1161 packet_put_cstring(""); /* lang */
1162 packet_put_cstring(options.kbd_interactive_devices ?
1163 options.kbd_interactive_devices : "");
1166 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1171 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1174 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1176 Authctxt *authctxt = ctxt;
1177 char *name, *inst, *lang, *prompt, *response;
1178 u_int num_prompts, i;
1181 debug2("input_userauth_info_req");
1183 if (authctxt == NULL)
1184 fatal("input_userauth_info_req: no authentication context");
1186 authctxt->info_req_seen = 1;
1188 name = packet_get_string(NULL);
1189 inst = packet_get_string(NULL);
1190 lang = packet_get_string(NULL);
1191 if (strlen(name) > 0)
1193 if (strlen(inst) > 0)
1199 num_prompts = packet_get_int();
1201 * Begin to build info response packet based on prompts requested.
1202 * We commit to providing the correct number of responses, so if
1203 * further on we run into a problem that prevents this, we have to
1204 * be sure and clean this up and send a correct error response.
1206 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1207 packet_put_int(num_prompts);
1209 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1210 for (i = 0; i < num_prompts; i++) {
1211 prompt = packet_get_string(NULL);
1212 echo = packet_get_char();
1214 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1216 packet_put_cstring(response);
1217 memset(response, 0, strlen(response));
1221 packet_check_eom(); /* done with parsing incoming message. */
1223 packet_add_padding(64);
1228 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1229 u_char *data, u_int datalen)
1234 int to[2], from[2], status, version = 2;
1236 debug2("ssh_keysign called");
1238 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1239 error("ssh_keysign: no installed: %s", strerror(errno));
1242 if (fflush(stdout) != 0)
1243 error("ssh_keysign: fflush: %s", strerror(errno));
1245 error("ssh_keysign: pipe: %s", strerror(errno));
1248 if (pipe(from) < 0) {
1249 error("ssh_keysign: pipe: %s", strerror(errno));
1252 if ((pid = fork()) < 0) {
1253 error("ssh_keysign: fork: %s", strerror(errno));
1257 permanently_drop_suid(getuid());
1259 if (dup2(from[1], STDOUT_FILENO) < 0)
1260 fatal("ssh_keysign: dup2: %s", strerror(errno));
1262 if (dup2(to[0], STDIN_FILENO) < 0)
1263 fatal("ssh_keysign: dup2: %s", strerror(errno));
1266 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1267 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1274 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1275 buffer_put_string(&b, data, datalen);
1276 if (ssh_msg_send(to[1], version, &b) == -1)
1277 fatal("ssh_keysign: couldn't send request");
1279 if (ssh_msg_recv(from[0], &b) < 0) {
1280 error("ssh_keysign: no reply");
1287 while (waitpid(pid, &status, 0) < 0)
1291 if (buffer_get_char(&b) != version) {
1292 error("ssh_keysign: bad version");
1296 *sigp = buffer_get_string(&b, lenp);
1303 userauth_hostbased(Authctxt *authctxt)
1305 Key *private = NULL;
1306 Sensitive *sensitive = authctxt->sensitive;
1308 u_char *signature, *blob;
1309 char *chost, *pkalg, *p;
1310 const char *service;
1312 int ok, i, len, found = 0;
1314 /* check for a useful key */
1315 for (i = 0; i < sensitive->nkeys; i++) {
1316 private = sensitive->keys[i];
1317 if (private && private->type != KEY_RSA1) {
1319 /* we take and free the key */
1320 sensitive->keys[i] = NULL;
1325 debug("No more client hostkeys for hostbased authentication.");
1328 if (key_to_blob(private, &blob, &blen) == 0) {
1332 /* figure out a name for the client host */
1333 p = get_local_name(packet_get_connection_in());
1335 error("userauth_hostbased: cannot get local ipaddr/name");
1340 len = strlen(p) + 2;
1341 xasprintf(&chost, "%s.", p);
1342 debug2("userauth_hostbased: chost %s", chost);
1345 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1347 pkalg = xstrdup(key_ssh_name(private));
1349 /* construct data */
1350 buffer_put_string(&b, session_id2, session_id2_len);
1351 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1352 buffer_put_cstring(&b, authctxt->server_user);
1353 buffer_put_cstring(&b, service);
1354 buffer_put_cstring(&b, authctxt->method->name);
1355 buffer_put_cstring(&b, pkalg);
1356 buffer_put_string(&b, blob, blen);
1357 buffer_put_cstring(&b, chost);
1358 buffer_put_cstring(&b, authctxt->local_user);
1362 if (sensitive->external_keysign)
1363 ok = ssh_keysign(private, &signature, &slen,
1364 buffer_ptr(&b), buffer_len(&b));
1366 ok = key_sign(private, &signature, &slen,
1367 buffer_ptr(&b), buffer_len(&b));
1371 error("key_sign failed");
1377 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1378 packet_put_cstring(authctxt->server_user);
1379 packet_put_cstring(authctxt->service);
1380 packet_put_cstring(authctxt->method->name);
1381 packet_put_cstring(pkalg);
1382 packet_put_string(blob, blen);
1383 packet_put_cstring(chost);
1384 packet_put_cstring(authctxt->local_user);
1385 packet_put_string(signature, slen);
1386 memset(signature, 's', slen);
1396 /* find auth method */
1399 * given auth method name, if configurable options permit this method fill
1400 * in auth_ident field and return true, otherwise return false.
1403 authmethod_is_enabled(Authmethod *method)
1407 /* return false if options indicate this method is disabled */
1408 if (method->enabled == NULL || *method->enabled == 0)
1410 /* return false if batch mode is enabled but method needs interactive mode */
1411 if (method->batch_flag != NULL && *method->batch_flag != 0)
1417 authmethod_lookup(const char *name)
1419 Authmethod *method = NULL;
1421 for (method = authmethods; method->name != NULL; method++)
1422 if (strcmp(name, method->name) == 0)
1424 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1428 /* XXX internal state */
1429 static Authmethod *current = NULL;
1430 static char *supported = NULL;
1431 static char *preferred = NULL;
1434 * Given the authentication method list sent by the server, return the
1435 * next method we should try. If the server initially sends a nil list,
1436 * use a built-in default list.
1439 authmethod_get(char *authlist)
1444 /* Use a suitable default if we're passed a nil list. */
1445 if (authlist == NULL || strlen(authlist) == 0)
1446 authlist = options.preferred_authentications;
1448 if (supported == NULL || strcmp(authlist, supported) != 0) {
1449 debug3("start over, passed a different list %s", authlist);
1450 if (supported != NULL)
1452 supported = xstrdup(authlist);
1453 preferred = options.preferred_authentications;
1454 debug3("preferred %s", preferred);
1456 } else if (current != NULL && authmethod_is_enabled(current))
1460 if ((name = match_list(preferred, supported, &next)) == NULL) {
1461 debug("No more authentication methods to try.");
1466 debug3("authmethod_lookup %s", name);
1467 debug3("remaining preferred: %s", preferred);
1468 if ((current = authmethod_lookup(name)) != NULL &&
1469 authmethod_is_enabled(current)) {
1470 debug3("authmethod_is_enabled %s", name);
1471 debug("Next authentication method: %s", name);
1478 authmethods_get(void)
1480 Authmethod *method = NULL;
1485 for (method = authmethods; method->name != NULL; method++) {
1486 if (authmethod_is_enabled(method)) {
1487 if (buffer_len(&b) > 0)
1488 buffer_append(&b, ",", 1);
1489 buffer_append(&b, method->name, strlen(method->name));
1492 buffer_append(&b, "\0", 1);
1493 list = xstrdup(buffer_ptr(&b));