1 /* $OpenBSD: sshconnect2.c,v 1.159 2006/08/01 23:22:48 stevesk 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>
37 #include "openbsd-compat/sys-queue.h"
48 #include "myproposal.h"
49 #include "sshconnect.h"
60 #include "pathnames.h"
68 extern char *client_version_string;
69 extern char *server_version_string;
70 extern Options options;
76 u_char *session_id2 = NULL;
77 u_int session_id2_len = 0;
80 struct sockaddr *xxx_hostaddr;
85 verify_host_key_callback(Key *hostkey)
87 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
88 fatal("Host key verification failed.");
93 ssh_kex2(char *host, struct sockaddr *hostaddr)
98 xxx_hostaddr = hostaddr;
100 if (options.ciphers == (char *)-1) {
101 logit("No valid ciphers for protocol version 2 given, using defaults.");
102 options.ciphers = NULL;
104 if (options.ciphers != NULL) {
105 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
106 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
108 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
109 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
110 myproposal[PROPOSAL_ENC_ALGS_STOC] =
111 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
112 if (options.compression) {
113 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
114 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
116 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
117 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
119 if (options.macs != NULL) {
120 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
121 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
123 if (options.hostkeyalgorithms != NULL)
124 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
125 options.hostkeyalgorithms;
127 if (options.rekey_limit)
128 packet_set_rekey_limit(options.rekey_limit);
130 /* start key exchange */
131 kex = kex_setup(myproposal);
132 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
133 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
134 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
135 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
136 kex->client_version_string=client_version_string;
137 kex->server_version_string=server_version_string;
138 kex->verify_host_key=&verify_host_key_callback;
142 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
144 session_id2 = kex->session_id;
145 session_id2_len = kex->session_id_len;
148 /* send 1st encrypted/maced/compressed message */
149 packet_start(SSH2_MSG_IGNORE);
150 packet_put_cstring("markus");
160 typedef struct Authctxt Authctxt;
161 typedef struct Authmethod Authmethod;
162 typedef struct identity Identity;
163 typedef struct idlist Idlist;
166 TAILQ_ENTRY(identity) next;
167 AuthenticationConnection *ac; /* set if agent supports key */
168 Key *key; /* public/private key */
169 char *filename; /* comment for agent-only keys */
171 int isprivate; /* key points to the private key */
173 TAILQ_HEAD(idlist, identity);
176 const char *server_user;
177 const char *local_user;
185 AuthenticationConnection *agent;
187 Sensitive *sensitive;
188 /* kbd-interactive */
194 char *name; /* string to compare against server's list */
195 int (*userauth)(Authctxt *authctxt);
196 int *enabled; /* flag in option struct that enables method */
197 int *batch_flag; /* flag in option struct that disables method */
200 void input_userauth_success(int, u_int32_t, void *);
201 void input_userauth_failure(int, u_int32_t, void *);
202 void input_userauth_banner(int, u_int32_t, void *);
203 void input_userauth_error(int, u_int32_t, void *);
204 void input_userauth_info_req(int, u_int32_t, void *);
205 void input_userauth_pk_ok(int, u_int32_t, void *);
206 void input_userauth_passwd_changereq(int, u_int32_t, void *);
208 int userauth_none(Authctxt *);
209 int userauth_pubkey(Authctxt *);
210 int userauth_passwd(Authctxt *);
211 int userauth_kbdint(Authctxt *);
212 int userauth_hostbased(Authctxt *);
213 int userauth_kerberos(Authctxt *);
216 int userauth_gssapi(Authctxt *authctxt);
217 void input_gssapi_response(int type, u_int32_t, void *);
218 void input_gssapi_token(int type, u_int32_t, void *);
219 void input_gssapi_hash(int type, u_int32_t, void *);
220 void input_gssapi_error(int, u_int32_t, void *);
221 void input_gssapi_errtok(int, u_int32_t, void *);
224 void userauth(Authctxt *, char *);
226 static int sign_and_send_pubkey(Authctxt *, Identity *);
227 static void pubkey_prepare(Authctxt *);
228 static void pubkey_cleanup(Authctxt *);
229 static Key *load_identity_file(char *);
231 static Authmethod *authmethod_get(char *authlist);
232 static Authmethod *authmethod_lookup(const char *name);
233 static char *authmethods_get(void);
235 Authmethod authmethods[] = {
239 &options.gss_authentication,
244 &options.hostbased_authentication,
248 &options.pubkey_authentication,
250 {"keyboard-interactive",
252 &options.kbd_interactive_authentication,
253 &options.batch_mode},
256 &options.password_authentication,
257 &options.batch_mode},
262 {NULL, NULL, NULL, NULL}
266 ssh_userauth2(const char *local_user, const char *server_user, char *host,
267 Sensitive *sensitive)
272 if (options.challenge_response_authentication)
273 options.kbd_interactive_authentication = 1;
275 packet_start(SSH2_MSG_SERVICE_REQUEST);
276 packet_put_cstring("ssh-userauth");
278 debug("SSH2_MSG_SERVICE_REQUEST sent");
280 type = packet_read();
281 if (type != SSH2_MSG_SERVICE_ACCEPT)
282 fatal("Server denied authentication request: %d", type);
283 if (packet_remaining() > 0) {
284 char *reply = packet_get_string(NULL);
285 debug2("service_accept: %s", reply);
288 debug2("buggy server: service_accept w/o service");
291 debug("SSH2_MSG_SERVICE_ACCEPT received");
293 if (options.preferred_authentications == NULL)
294 options.preferred_authentications = authmethods_get();
296 /* setup authentication context */
297 memset(&authctxt, 0, sizeof(authctxt));
298 pubkey_prepare(&authctxt);
299 authctxt.server_user = server_user;
300 authctxt.local_user = local_user;
301 authctxt.host = host;
302 authctxt.service = "ssh-connection"; /* service name */
303 authctxt.success = 0;
304 authctxt.method = authmethod_lookup("none");
305 authctxt.authlist = NULL;
306 authctxt.methoddata = NULL;
307 authctxt.sensitive = sensitive;
308 authctxt.info_req_seen = 0;
309 if (authctxt.method == NULL)
310 fatal("ssh_userauth2: internal error: cannot send userauth none request");
312 /* initial userauth request */
313 userauth_none(&authctxt);
315 dispatch_init(&input_userauth_error);
316 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
317 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
318 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
319 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
321 pubkey_cleanup(&authctxt);
322 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
324 debug("Authentication succeeded (%s).", authctxt.method->name);
328 userauth(Authctxt *authctxt, char *authlist)
330 if (authctxt->methoddata) {
331 xfree(authctxt->methoddata);
332 authctxt->methoddata = NULL;
334 if (authlist == NULL) {
335 authlist = authctxt->authlist;
337 if (authctxt->authlist)
338 xfree(authctxt->authlist);
339 authctxt->authlist = authlist;
342 Authmethod *method = authmethod_get(authlist);
344 fatal("Permission denied (%s).", authlist);
345 authctxt->method = method;
347 /* reset the per method handler */
348 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
349 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
351 /* and try new method */
352 if (method->userauth(authctxt) != 0) {
353 debug2("we sent a %s packet, wait for reply", method->name);
356 debug2("we did not send a packet, disable method");
357 method->enabled = NULL;
363 input_userauth_error(int type, u_int32_t seq, void *ctxt)
365 fatal("input_userauth_error: bad message during authentication: "
370 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
374 debug3("input_userauth_banner");
375 msg = packet_get_string(NULL);
376 lang = packet_get_string(NULL);
377 if (options.log_level > SYSLOG_LEVEL_QUIET)
378 fprintf(stderr, "%s", msg);
384 input_userauth_success(int type, u_int32_t seq, void *ctxt)
386 Authctxt *authctxt = ctxt;
387 if (authctxt == NULL)
388 fatal("input_userauth_success: no authentication context");
389 if (authctxt->authlist) {
390 xfree(authctxt->authlist);
391 authctxt->authlist = NULL;
393 if (authctxt->methoddata) {
394 xfree(authctxt->methoddata);
395 authctxt->methoddata = NULL;
397 authctxt->success = 1; /* break out */
401 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
403 Authctxt *authctxt = ctxt;
404 char *authlist = NULL;
407 if (authctxt == NULL)
408 fatal("input_userauth_failure: no authentication context");
410 authlist = packet_get_string(NULL);
411 partial = packet_get_char();
415 logit("Authenticated with partial success.");
416 debug("Authentications that can continue: %s", authlist);
418 userauth(authctxt, authlist);
421 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
423 Authctxt *authctxt = ctxt;
427 int pktype, sent = 0;
432 if (authctxt == NULL)
433 fatal("input_userauth_pk_ok: no authentication context");
434 if (datafellows & SSH_BUG_PKOK) {
435 /* this is similar to SSH_BUG_PKAUTH */
436 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
437 pkblob = packet_get_string(&blen);
439 buffer_append(&b, pkblob, blen);
440 pkalg = buffer_get_string(&b, &alen);
443 pkalg = packet_get_string(&alen);
444 pkblob = packet_get_string(&blen);
448 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
450 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
451 debug("unknown pkalg %s", pkalg);
454 if ((key = key_from_blob(pkblob, blen)) == NULL) {
455 debug("no key from blob. pkalg %s", pkalg);
458 if (key->type != pktype) {
459 error("input_userauth_pk_ok: type mismatch "
460 "for decoded key (received %d, expected %d)",
464 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
465 debug2("input_userauth_pk_ok: fp %s", fp);
469 * search keys in the reverse order, because last candidate has been
470 * moved to the end of the queue. this also avoids confusion by
473 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
474 if (key_equal(key, id->key)) {
475 sent = sign_and_send_pubkey(authctxt, id);
485 /* try another method if we did not send a packet */
487 userauth(authctxt, NULL);
492 userauth_gssapi(Authctxt *authctxt)
494 Gssctxt *gssctxt = NULL;
495 static gss_OID_set gss_supported = NULL;
496 static u_int mech = 0;
500 /* Try one GSSAPI method at a time, rather than sending them all at
503 if (gss_supported == NULL)
504 gss_indicate_mechs(&min, &gss_supported);
506 /* Check to see if the mechanism is usable before we offer it */
507 while (mech < gss_supported->count && !ok) {
509 ssh_gssapi_delete_ctx(&gssctxt);
510 ssh_gssapi_build_ctx(&gssctxt);
511 ssh_gssapi_set_oid(gssctxt, &gss_supported->elements[mech]);
513 /* My DER encoding requires length<128 */
514 if (gss_supported->elements[mech].length < 128 &&
515 !GSS_ERROR(ssh_gssapi_import_name(gssctxt,
517 ok = 1; /* Mechanism works */
524 ssh_gssapi_delete_ctx(&gssctxt);
528 authctxt->methoddata=(void *)gssctxt;
530 packet_start(SSH2_MSG_USERAUTH_REQUEST);
531 packet_put_cstring(authctxt->server_user);
532 packet_put_cstring(authctxt->service);
533 packet_put_cstring(authctxt->method->name);
537 packet_put_int((gss_supported->elements[mech].length) + 2);
538 packet_put_char(SSH_GSS_OIDTYPE);
539 packet_put_char(gss_supported->elements[mech].length);
540 packet_put_raw(gss_supported->elements[mech].elements,
541 gss_supported->elements[mech].length);
545 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
546 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
547 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
548 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
550 mech++; /* Move along to next candidate */
556 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
558 Authctxt *authctxt = ctxt;
559 Gssctxt *gssctxt = authctxt->methoddata;
560 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
561 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
562 gss_buffer_desc gssbuf;
563 OM_uint32 status, ms, flags;
566 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
567 recv_tok, &send_tok, &flags);
569 if (send_tok.length > 0) {
570 if (GSS_ERROR(status))
571 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
573 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
575 packet_put_string(send_tok.value, send_tok.length);
577 gss_release_buffer(&ms, &send_tok);
580 if (status == GSS_S_COMPLETE) {
581 /* send either complete or MIC, depending on mechanism */
582 if (!(flags & GSS_C_INTEG_FLAG)) {
583 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
586 ssh_gssapi_buildmic(&b, authctxt->server_user,
587 authctxt->service, "gssapi-with-mic");
589 gssbuf.value = buffer_ptr(&b);
590 gssbuf.length = buffer_len(&b);
592 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
594 if (!GSS_ERROR(status)) {
595 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
596 packet_put_string(mic.value, mic.length);
602 gss_release_buffer(&ms, &mic);
610 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
612 Authctxt *authctxt = ctxt;
617 if (authctxt == NULL)
618 fatal("input_gssapi_response: no authentication context");
619 gssctxt = authctxt->methoddata;
622 oidv = packet_get_string(&oidlen);
625 oidv[0] != SSH_GSS_OIDTYPE ||
626 oidv[1] != oidlen - 2) {
628 debug("Badly encoded mechanism OID received");
629 userauth(authctxt, NULL);
633 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
634 fatal("Server returned different OID than expected");
640 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
641 /* Start again with next method on list */
642 debug("Trying to start again");
643 userauth(authctxt, NULL);
649 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
651 Authctxt *authctxt = ctxt;
652 gss_buffer_desc recv_tok;
656 if (authctxt == NULL)
657 fatal("input_gssapi_response: no authentication context");
659 recv_tok.value = packet_get_string(&slen);
660 recv_tok.length = slen; /* safe typecast */
664 status = process_gssapi_token(ctxt, &recv_tok);
666 xfree(recv_tok.value);
668 if (GSS_ERROR(status)) {
669 /* Start again with the next method in the list */
670 userauth(authctxt, NULL);
676 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
678 Authctxt *authctxt = ctxt;
680 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
681 gss_buffer_desc recv_tok;
682 OM_uint32 status, ms;
685 if (authctxt == NULL)
686 fatal("input_gssapi_response: no authentication context");
687 gssctxt = authctxt->methoddata;
689 recv_tok.value = packet_get_string(&len);
690 recv_tok.length = len;
694 /* Stick it into GSSAPI and see what it says */
695 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
696 &recv_tok, &send_tok, NULL);
698 xfree(recv_tok.value);
699 gss_release_buffer(&ms, &send_tok);
701 /* Server will be returning a failed packet after this one */
705 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
711 maj=packet_get_int();
712 min=packet_get_int();
713 msg=packet_get_string(NULL);
714 lang=packet_get_string(NULL);
718 debug("Server GSSAPI Error:\n%s", msg);
725 userauth_none(Authctxt *authctxt)
727 /* initial userauth request */
728 packet_start(SSH2_MSG_USERAUTH_REQUEST);
729 packet_put_cstring(authctxt->server_user);
730 packet_put_cstring(authctxt->service);
731 packet_put_cstring(authctxt->method->name);
737 userauth_passwd(Authctxt *authctxt)
739 static int attempt = 0;
743 if (attempt++ >= options.number_of_password_prompts)
747 error("Permission denied, please try again.");
749 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
750 authctxt->server_user, authctxt->host);
751 password = read_passphrase(prompt, 0);
752 packet_start(SSH2_MSG_USERAUTH_REQUEST);
753 packet_put_cstring(authctxt->server_user);
754 packet_put_cstring(authctxt->service);
755 packet_put_cstring(authctxt->method->name);
757 packet_put_cstring(password);
758 memset(password, 0, strlen(password));
760 packet_add_padding(64);
763 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
764 &input_userauth_passwd_changereq);
769 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
772 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
774 Authctxt *authctxt = ctxt;
775 char *info, *lang, *password = NULL, *retype = NULL;
778 debug2("input_userauth_passwd_changereq");
780 if (authctxt == NULL)
781 fatal("input_userauth_passwd_changereq: "
782 "no authentication context");
784 info = packet_get_string(NULL);
785 lang = packet_get_string(NULL);
786 if (strlen(info) > 0)
790 packet_start(SSH2_MSG_USERAUTH_REQUEST);
791 packet_put_cstring(authctxt->server_user);
792 packet_put_cstring(authctxt->service);
793 packet_put_cstring(authctxt->method->name);
794 packet_put_char(1); /* additional info */
795 snprintf(prompt, sizeof(prompt),
796 "Enter %.30s@%.128s's old password: ",
797 authctxt->server_user, authctxt->host);
798 password = read_passphrase(prompt, 0);
799 packet_put_cstring(password);
800 memset(password, 0, strlen(password));
803 while (password == NULL) {
804 snprintf(prompt, sizeof(prompt),
805 "Enter %.30s@%.128s's new password: ",
806 authctxt->server_user, authctxt->host);
807 password = read_passphrase(prompt, RP_ALLOW_EOF);
808 if (password == NULL) {
812 snprintf(prompt, sizeof(prompt),
813 "Retype %.30s@%.128s's new password: ",
814 authctxt->server_user, authctxt->host);
815 retype = read_passphrase(prompt, 0);
816 if (strcmp(password, retype) != 0) {
817 memset(password, 0, strlen(password));
819 logit("Mismatch; try again, EOF to quit.");
822 memset(retype, 0, strlen(retype));
825 packet_put_cstring(password);
826 memset(password, 0, strlen(password));
828 packet_add_padding(64);
831 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
832 &input_userauth_passwd_changereq);
836 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
837 u_char *data, u_int datalen)
842 /* the agent supports this key */
844 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
847 * we have already loaded the private key or
848 * the private key is stored in external hardware
850 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
851 return (key_sign(id->key, sigp, lenp, data, datalen));
852 /* load the private key from the file */
853 if ((prv = load_identity_file(id->filename)) == NULL)
855 ret = key_sign(prv, sigp, lenp, data, datalen);
861 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
864 u_char *blob, *signature;
870 debug3("sign_and_send_pubkey");
872 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
873 /* we cannot handle this key */
874 debug3("sign_and_send_pubkey: cannot handle key");
877 /* data to be signed */
879 if (datafellows & SSH_OLD_SESSIONID) {
880 buffer_append(&b, session_id2, session_id2_len);
881 skip = session_id2_len;
883 buffer_put_string(&b, session_id2, session_id2_len);
884 skip = buffer_len(&b);
886 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
887 buffer_put_cstring(&b, authctxt->server_user);
888 buffer_put_cstring(&b,
889 datafellows & SSH_BUG_PKSERVICE ?
892 if (datafellows & SSH_BUG_PKAUTH) {
893 buffer_put_char(&b, have_sig);
895 buffer_put_cstring(&b, authctxt->method->name);
896 buffer_put_char(&b, have_sig);
897 buffer_put_cstring(&b, key_ssh_name(id->key));
899 buffer_put_string(&b, blob, bloblen);
901 /* generate signature */
902 ret = identity_sign(id, &signature, &slen,
903 buffer_ptr(&b), buffer_len(&b));
912 if (datafellows & SSH_BUG_PKSERVICE) {
914 buffer_append(&b, session_id2, session_id2_len);
915 skip = session_id2_len;
916 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
917 buffer_put_cstring(&b, authctxt->server_user);
918 buffer_put_cstring(&b, authctxt->service);
919 buffer_put_cstring(&b, authctxt->method->name);
920 buffer_put_char(&b, have_sig);
921 if (!(datafellows & SSH_BUG_PKAUTH))
922 buffer_put_cstring(&b, key_ssh_name(id->key));
923 buffer_put_string(&b, blob, bloblen);
927 /* append signature */
928 buffer_put_string(&b, signature, slen);
931 /* skip session id and packet type */
932 if (buffer_len(&b) < skip + 1)
933 fatal("userauth_pubkey: internal error");
934 buffer_consume(&b, skip + 1);
936 /* put remaining data from buffer into packet */
937 packet_start(SSH2_MSG_USERAUTH_REQUEST);
938 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
946 send_pubkey_test(Authctxt *authctxt, Identity *id)
949 u_int bloblen, have_sig = 0;
951 debug3("send_pubkey_test");
953 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
954 /* we cannot handle this key */
955 debug3("send_pubkey_test: cannot handle key");
958 /* register callback for USERAUTH_PK_OK message */
959 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
961 packet_start(SSH2_MSG_USERAUTH_REQUEST);
962 packet_put_cstring(authctxt->server_user);
963 packet_put_cstring(authctxt->service);
964 packet_put_cstring(authctxt->method->name);
965 packet_put_char(have_sig);
966 if (!(datafellows & SSH_BUG_PKAUTH))
967 packet_put_cstring(key_ssh_name(id->key));
968 packet_put_string(blob, bloblen);
975 load_identity_file(char *filename)
978 char prompt[300], *passphrase;
979 int perm_ok, quit, i;
982 if (stat(filename, &st) < 0) {
983 debug3("no such identity: %s", filename);
986 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
989 if (private == NULL) {
990 if (options.batch_mode)
992 snprintf(prompt, sizeof prompt,
993 "Enter passphrase for key '%.100s': ", filename);
994 for (i = 0; i < options.number_of_password_prompts; i++) {
995 passphrase = read_passphrase(prompt, 0);
996 if (strcmp(passphrase, "") != 0) {
997 private = key_load_private_type(KEY_UNSPEC,
998 filename, passphrase, NULL, NULL);
1001 debug2("no passphrase given, try next key");
1004 memset(passphrase, 0, strlen(passphrase));
1006 if (private != NULL || quit)
1008 debug2("bad passphrase given, try again...");
1015 * try keys in the following order:
1016 * 1. agent keys that are found in the config file
1017 * 2. other agent keys
1018 * 3. keys that are only listed in the config file
1021 pubkey_prepare(Authctxt *authctxt)
1024 Idlist agent, files, *preferred;
1026 AuthenticationConnection *ac;
1030 TAILQ_INIT(&agent); /* keys from the agent */
1031 TAILQ_INIT(&files); /* keys from the config file */
1032 preferred = &authctxt->keys;
1033 TAILQ_INIT(preferred); /* preferred order of keys */
1035 /* list of keys stored in the filesystem */
1036 for (i = 0; i < options.num_identity_files; i++) {
1037 key = options.identity_keys[i];
1038 if (key && key->type == KEY_RSA1)
1040 options.identity_keys[i] = NULL;
1041 id = xcalloc(1, sizeof(*id));
1043 id->filename = xstrdup(options.identity_files[i]);
1044 TAILQ_INSERT_TAIL(&files, id, next);
1046 /* list of keys supported by the agent */
1047 if ((ac = ssh_get_authentication_connection())) {
1048 for (key = ssh_get_first_identity(ac, &comment, 2);
1050 key = ssh_get_next_identity(ac, &comment, 2)) {
1052 TAILQ_FOREACH(id, &files, next) {
1053 /* agent keys from the config file are preferred */
1054 if (key_equal(key, id->key)) {
1057 TAILQ_REMOVE(&files, id, next);
1058 TAILQ_INSERT_TAIL(preferred, id, next);
1064 if (!found && !options.identities_only) {
1065 id = xcalloc(1, sizeof(*id));
1067 id->filename = comment;
1069 TAILQ_INSERT_TAIL(&agent, id, next);
1072 /* append remaining agent keys */
1073 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1074 TAILQ_REMOVE(&agent, id, next);
1075 TAILQ_INSERT_TAIL(preferred, id, next);
1077 authctxt->agent = ac;
1079 /* append remaining keys from the config file */
1080 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1081 TAILQ_REMOVE(&files, id, next);
1082 TAILQ_INSERT_TAIL(preferred, id, next);
1084 TAILQ_FOREACH(id, preferred, next) {
1085 debug2("key: %s (%p)", id->filename, id->key);
1090 pubkey_cleanup(Authctxt *authctxt)
1094 if (authctxt->agent != NULL)
1095 ssh_close_authentication_connection(authctxt->agent);
1096 for (id = TAILQ_FIRST(&authctxt->keys); id;
1097 id = TAILQ_FIRST(&authctxt->keys)) {
1098 TAILQ_REMOVE(&authctxt->keys, id, next);
1102 xfree(id->filename);
1108 userauth_pubkey(Authctxt *authctxt)
1113 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1116 /* move key to the end of the queue */
1117 TAILQ_REMOVE(&authctxt->keys, id, next);
1118 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1120 * send a test message if we have the public key. for
1121 * encrypted keys we cannot do this and have to load the
1122 * private key instead
1124 if (id->key && id->key->type != KEY_RSA1) {
1125 debug("Offering public key: %s", id->filename);
1126 sent = send_pubkey_test(authctxt, id);
1127 } else if (id->key == NULL) {
1128 debug("Trying private key: %s", id->filename);
1129 id->key = load_identity_file(id->filename);
1130 if (id->key != NULL) {
1132 sent = sign_and_send_pubkey(authctxt, id);
1144 * Send userauth request message specifying keyboard-interactive method.
1147 userauth_kbdint(Authctxt *authctxt)
1149 static int attempt = 0;
1151 if (attempt++ >= options.number_of_password_prompts)
1153 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1154 if (attempt > 1 && !authctxt->info_req_seen) {
1155 debug3("userauth_kbdint: disable: no info_req_seen");
1156 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1160 debug2("userauth_kbdint");
1161 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1162 packet_put_cstring(authctxt->server_user);
1163 packet_put_cstring(authctxt->service);
1164 packet_put_cstring(authctxt->method->name);
1165 packet_put_cstring(""); /* lang */
1166 packet_put_cstring(options.kbd_interactive_devices ?
1167 options.kbd_interactive_devices : "");
1170 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1175 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1178 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1180 Authctxt *authctxt = ctxt;
1181 char *name, *inst, *lang, *prompt, *response;
1182 u_int num_prompts, i;
1185 debug2("input_userauth_info_req");
1187 if (authctxt == NULL)
1188 fatal("input_userauth_info_req: no authentication context");
1190 authctxt->info_req_seen = 1;
1192 name = packet_get_string(NULL);
1193 inst = packet_get_string(NULL);
1194 lang = packet_get_string(NULL);
1195 if (strlen(name) > 0)
1197 if (strlen(inst) > 0)
1203 num_prompts = packet_get_int();
1205 * Begin to build info response packet based on prompts requested.
1206 * We commit to providing the correct number of responses, so if
1207 * further on we run into a problem that prevents this, we have to
1208 * be sure and clean this up and send a correct error response.
1210 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1211 packet_put_int(num_prompts);
1213 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1214 for (i = 0; i < num_prompts; i++) {
1215 prompt = packet_get_string(NULL);
1216 echo = packet_get_char();
1218 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1220 packet_put_cstring(response);
1221 memset(response, 0, strlen(response));
1225 packet_check_eom(); /* done with parsing incoming message. */
1227 packet_add_padding(64);
1232 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1233 u_char *data, u_int datalen)
1238 int to[2], from[2], status, version = 2;
1240 debug2("ssh_keysign called");
1242 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1243 error("ssh_keysign: no installed: %s", strerror(errno));
1246 if (fflush(stdout) != 0)
1247 error("ssh_keysign: fflush: %s", strerror(errno));
1249 error("ssh_keysign: pipe: %s", strerror(errno));
1252 if (pipe(from) < 0) {
1253 error("ssh_keysign: pipe: %s", strerror(errno));
1256 if ((pid = fork()) < 0) {
1257 error("ssh_keysign: fork: %s", strerror(errno));
1261 permanently_drop_suid(getuid());
1263 if (dup2(from[1], STDOUT_FILENO) < 0)
1264 fatal("ssh_keysign: dup2: %s", strerror(errno));
1266 if (dup2(to[0], STDIN_FILENO) < 0)
1267 fatal("ssh_keysign: dup2: %s", strerror(errno));
1270 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1271 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1278 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1279 buffer_put_string(&b, data, datalen);
1280 if (ssh_msg_send(to[1], version, &b) == -1)
1281 fatal("ssh_keysign: couldn't send request");
1283 if (ssh_msg_recv(from[0], &b) < 0) {
1284 error("ssh_keysign: no reply");
1291 while (waitpid(pid, &status, 0) < 0)
1295 if (buffer_get_char(&b) != version) {
1296 error("ssh_keysign: bad version");
1300 *sigp = buffer_get_string(&b, lenp);
1307 userauth_hostbased(Authctxt *authctxt)
1309 Key *private = NULL;
1310 Sensitive *sensitive = authctxt->sensitive;
1312 u_char *signature, *blob;
1313 char *chost, *pkalg, *p;
1314 const char *service;
1316 int ok, i, len, found = 0;
1318 /* check for a useful key */
1319 for (i = 0; i < sensitive->nkeys; i++) {
1320 private = sensitive->keys[i];
1321 if (private && private->type != KEY_RSA1) {
1323 /* we take and free the key */
1324 sensitive->keys[i] = NULL;
1329 debug("No more client hostkeys for hostbased authentication.");
1332 if (key_to_blob(private, &blob, &blen) == 0) {
1336 /* figure out a name for the client host */
1337 p = get_local_name(packet_get_connection_in());
1339 error("userauth_hostbased: cannot get local ipaddr/name");
1344 len = strlen(p) + 2;
1345 xasprintf(&chost, "%s.", p);
1346 debug2("userauth_hostbased: chost %s", chost);
1349 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1351 pkalg = xstrdup(key_ssh_name(private));
1353 /* construct data */
1354 buffer_put_string(&b, session_id2, session_id2_len);
1355 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1356 buffer_put_cstring(&b, authctxt->server_user);
1357 buffer_put_cstring(&b, service);
1358 buffer_put_cstring(&b, authctxt->method->name);
1359 buffer_put_cstring(&b, pkalg);
1360 buffer_put_string(&b, blob, blen);
1361 buffer_put_cstring(&b, chost);
1362 buffer_put_cstring(&b, authctxt->local_user);
1366 if (sensitive->external_keysign)
1367 ok = ssh_keysign(private, &signature, &slen,
1368 buffer_ptr(&b), buffer_len(&b));
1370 ok = key_sign(private, &signature, &slen,
1371 buffer_ptr(&b), buffer_len(&b));
1375 error("key_sign failed");
1381 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1382 packet_put_cstring(authctxt->server_user);
1383 packet_put_cstring(authctxt->service);
1384 packet_put_cstring(authctxt->method->name);
1385 packet_put_cstring(pkalg);
1386 packet_put_string(blob, blen);
1387 packet_put_cstring(chost);
1388 packet_put_cstring(authctxt->local_user);
1389 packet_put_string(signature, slen);
1390 memset(signature, 's', slen);
1400 /* find auth method */
1403 * given auth method name, if configurable options permit this method fill
1404 * in auth_ident field and return true, otherwise return false.
1407 authmethod_is_enabled(Authmethod *method)
1411 /* return false if options indicate this method is disabled */
1412 if (method->enabled == NULL || *method->enabled == 0)
1414 /* return false if batch mode is enabled but method needs interactive mode */
1415 if (method->batch_flag != NULL && *method->batch_flag != 0)
1421 authmethod_lookup(const char *name)
1423 Authmethod *method = NULL;
1425 for (method = authmethods; method->name != NULL; method++)
1426 if (strcmp(name, method->name) == 0)
1428 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1432 /* XXX internal state */
1433 static Authmethod *current = NULL;
1434 static char *supported = NULL;
1435 static char *preferred = NULL;
1438 * Given the authentication method list sent by the server, return the
1439 * next method we should try. If the server initially sends a nil list,
1440 * use a built-in default list.
1443 authmethod_get(char *authlist)
1448 /* Use a suitable default if we're passed a nil list. */
1449 if (authlist == NULL || strlen(authlist) == 0)
1450 authlist = options.preferred_authentications;
1452 if (supported == NULL || strcmp(authlist, supported) != 0) {
1453 debug3("start over, passed a different list %s", authlist);
1454 if (supported != NULL)
1456 supported = xstrdup(authlist);
1457 preferred = options.preferred_authentications;
1458 debug3("preferred %s", preferred);
1460 } else if (current != NULL && authmethod_is_enabled(current))
1464 if ((name = match_list(preferred, supported, &next)) == NULL) {
1465 debug("No more authentication methods to try.");
1470 debug3("authmethod_lookup %s", name);
1471 debug3("remaining preferred: %s", preferred);
1472 if ((current = authmethod_lookup(name)) != NULL &&
1473 authmethod_is_enabled(current)) {
1474 debug3("authmethod_is_enabled %s", name);
1475 debug("Next authentication method: %s", name);
1482 authmethods_get(void)
1484 Authmethod *method = NULL;
1489 for (method = authmethods; method->name != NULL; method++) {
1490 if (authmethod_is_enabled(method)) {
1491 if (buffer_len(&b) > 0)
1492 buffer_append(&b, ",", 1);
1493 buffer_append(&b, method->name, strlen(method->name));
1496 buffer_append(&b, "\0", 1);
1497 list = xstrdup(buffer_ptr(&b));