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 1.143 2005/10/14 02:17:59 stevesk Exp $");
28 #include "openbsd-compat/sys-queue.h"
39 #include "myproposal.h"
40 #include "sshconnect.h"
51 #include "pathnames.h"
58 extern char *client_version_string;
59 extern char *server_version_string;
60 extern Options options;
66 u_char *session_id2 = NULL;
67 u_int session_id2_len = 0;
70 struct sockaddr *xxx_hostaddr;
75 verify_host_key_callback(Key *hostkey)
77 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
78 fatal("Host key verification failed.");
83 ssh_kex2(char *host, struct sockaddr *hostaddr)
88 xxx_hostaddr = hostaddr;
90 if (options.ciphers == (char *)-1) {
91 logit("No valid ciphers for protocol version 2 given, using defaults.");
92 options.ciphers = NULL;
94 if (options.ciphers != NULL) {
95 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
96 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
98 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
99 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
100 myproposal[PROPOSAL_ENC_ALGS_STOC] =
101 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
102 if (options.compression) {
103 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
104 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
106 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
107 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
109 if (options.macs != NULL) {
110 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
111 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
113 if (options.hostkeyalgorithms != NULL)
114 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
115 options.hostkeyalgorithms;
117 if (options.rekey_limit)
118 packet_set_rekey_limit(options.rekey_limit);
120 /* start key exchange */
121 kex = kex_setup(myproposal);
122 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
123 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
124 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
125 kex->client_version_string=client_version_string;
126 kex->server_version_string=server_version_string;
127 kex->verify_host_key=&verify_host_key_callback;
131 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
133 session_id2 = kex->session_id;
134 session_id2_len = kex->session_id_len;
137 /* send 1st encrypted/maced/compressed message */
138 packet_start(SSH2_MSG_IGNORE);
139 packet_put_cstring("markus");
149 typedef struct Authctxt Authctxt;
150 typedef struct Authmethod Authmethod;
151 typedef struct identity Identity;
152 typedef struct idlist Idlist;
155 TAILQ_ENTRY(identity) next;
156 AuthenticationConnection *ac; /* set if agent supports key */
157 Key *key; /* public/private key */
158 char *filename; /* comment for agent-only keys */
160 int isprivate; /* key points to the private key */
162 TAILQ_HEAD(idlist, identity);
165 const char *server_user;
166 const char *local_user;
174 AuthenticationConnection *agent;
176 Sensitive *sensitive;
177 /* kbd-interactive */
183 char *name; /* string to compare against server's list */
184 int (*userauth)(Authctxt *authctxt);
185 int *enabled; /* flag in option struct that enables method */
186 int *batch_flag; /* flag in option struct that disables method */
189 void input_userauth_success(int, u_int32_t, void *);
190 void input_userauth_failure(int, u_int32_t, void *);
191 void input_userauth_banner(int, u_int32_t, void *);
192 void input_userauth_error(int, u_int32_t, void *);
193 void input_userauth_info_req(int, u_int32_t, void *);
194 void input_userauth_pk_ok(int, u_int32_t, void *);
195 void input_userauth_passwd_changereq(int, u_int32_t, void *);
197 int userauth_none(Authctxt *);
198 int userauth_pubkey(Authctxt *);
199 int userauth_passwd(Authctxt *);
200 int userauth_kbdint(Authctxt *);
201 int userauth_hostbased(Authctxt *);
202 int userauth_kerberos(Authctxt *);
205 int userauth_gssapi(Authctxt *authctxt);
206 void input_gssapi_response(int type, u_int32_t, void *);
207 void input_gssapi_token(int type, u_int32_t, void *);
208 void input_gssapi_hash(int type, u_int32_t, void *);
209 void input_gssapi_error(int, u_int32_t, void *);
210 void input_gssapi_errtok(int, u_int32_t, void *);
213 void userauth(Authctxt *, char *);
215 static int sign_and_send_pubkey(Authctxt *, Identity *);
216 static void pubkey_prepare(Authctxt *);
217 static void pubkey_cleanup(Authctxt *);
218 static Key *load_identity_file(char *);
220 static Authmethod *authmethod_get(char *authlist);
221 static Authmethod *authmethod_lookup(const char *name);
222 static char *authmethods_get(void);
224 Authmethod authmethods[] = {
228 &options.gss_authentication,
233 &options.hostbased_authentication,
237 &options.pubkey_authentication,
239 {"keyboard-interactive",
241 &options.kbd_interactive_authentication,
242 &options.batch_mode},
245 &options.password_authentication,
246 &options.batch_mode},
251 {NULL, NULL, NULL, NULL}
255 ssh_userauth2(const char *local_user, const char *server_user, char *host,
256 Sensitive *sensitive)
261 if (options.challenge_response_authentication)
262 options.kbd_interactive_authentication = 1;
264 packet_start(SSH2_MSG_SERVICE_REQUEST);
265 packet_put_cstring("ssh-userauth");
267 debug("SSH2_MSG_SERVICE_REQUEST sent");
269 type = packet_read();
270 if (type != SSH2_MSG_SERVICE_ACCEPT)
271 fatal("Server denied authentication request: %d", type);
272 if (packet_remaining() > 0) {
273 char *reply = packet_get_string(NULL);
274 debug2("service_accept: %s", reply);
277 debug2("buggy server: service_accept w/o service");
280 debug("SSH2_MSG_SERVICE_ACCEPT received");
282 if (options.preferred_authentications == NULL)
283 options.preferred_authentications = authmethods_get();
285 /* setup authentication context */
286 memset(&authctxt, 0, sizeof(authctxt));
287 pubkey_prepare(&authctxt);
288 authctxt.server_user = server_user;
289 authctxt.local_user = local_user;
290 authctxt.host = host;
291 authctxt.service = "ssh-connection"; /* service name */
292 authctxt.success = 0;
293 authctxt.method = authmethod_lookup("none");
294 authctxt.authlist = NULL;
295 authctxt.methoddata = NULL;
296 authctxt.sensitive = sensitive;
297 authctxt.info_req_seen = 0;
298 if (authctxt.method == NULL)
299 fatal("ssh_userauth2: internal error: cannot send userauth none request");
301 /* initial userauth request */
302 userauth_none(&authctxt);
304 dispatch_init(&input_userauth_error);
305 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
306 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
307 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
308 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
310 pubkey_cleanup(&authctxt);
311 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
313 debug("Authentication succeeded (%s).", authctxt.method->name);
317 userauth(Authctxt *authctxt, char *authlist)
319 if (authctxt->methoddata) {
320 xfree(authctxt->methoddata);
321 authctxt->methoddata = NULL;
323 if (authlist == NULL) {
324 authlist = authctxt->authlist;
326 if (authctxt->authlist)
327 xfree(authctxt->authlist);
328 authctxt->authlist = authlist;
331 Authmethod *method = authmethod_get(authlist);
333 fatal("Permission denied (%s).", authlist);
334 authctxt->method = method;
336 /* reset the per method handler */
337 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
338 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
340 /* and try new method */
341 if (method->userauth(authctxt) != 0) {
342 debug2("we sent a %s packet, wait for reply", method->name);
345 debug2("we did not send a packet, disable method");
346 method->enabled = NULL;
352 input_userauth_error(int type, u_int32_t seq, void *ctxt)
354 fatal("input_userauth_error: bad message during authentication: "
359 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
363 debug3("input_userauth_banner");
364 msg = packet_get_string(NULL);
365 lang = packet_get_string(NULL);
366 if (options.log_level > SYSLOG_LEVEL_QUIET)
367 fprintf(stderr, "%s", msg);
373 input_userauth_success(int type, u_int32_t seq, void *ctxt)
375 Authctxt *authctxt = ctxt;
376 if (authctxt == NULL)
377 fatal("input_userauth_success: no authentication context");
378 if (authctxt->authlist) {
379 xfree(authctxt->authlist);
380 authctxt->authlist = NULL;
382 if (authctxt->methoddata) {
383 xfree(authctxt->methoddata);
384 authctxt->methoddata = NULL;
386 authctxt->success = 1; /* break out */
390 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
392 Authctxt *authctxt = ctxt;
393 char *authlist = NULL;
396 if (authctxt == NULL)
397 fatal("input_userauth_failure: no authentication context");
399 authlist = packet_get_string(NULL);
400 partial = packet_get_char();
404 logit("Authenticated with partial success.");
405 debug("Authentications that can continue: %s", authlist);
407 userauth(authctxt, authlist);
410 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
412 Authctxt *authctxt = ctxt;
416 int pktype, sent = 0;
421 if (authctxt == NULL)
422 fatal("input_userauth_pk_ok: no authentication context");
423 if (datafellows & SSH_BUG_PKOK) {
424 /* this is similar to SSH_BUG_PKAUTH */
425 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
426 pkblob = packet_get_string(&blen);
428 buffer_append(&b, pkblob, blen);
429 pkalg = buffer_get_string(&b, &alen);
432 pkalg = packet_get_string(&alen);
433 pkblob = packet_get_string(&blen);
437 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
439 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
440 debug("unknown pkalg %s", pkalg);
443 if ((key = key_from_blob(pkblob, blen)) == NULL) {
444 debug("no key from blob. pkalg %s", pkalg);
447 if (key->type != pktype) {
448 error("input_userauth_pk_ok: type mismatch "
449 "for decoded key (received %d, expected %d)",
453 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
454 debug2("input_userauth_pk_ok: fp %s", fp);
458 * search keys in the reverse order, because last candidate has been
459 * moved to the end of the queue. this also avoids confusion by
462 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
463 if (key_equal(key, id->key)) {
464 sent = sign_and_send_pubkey(authctxt, id);
474 /* try another method if we did not send a packet */
476 userauth(authctxt, NULL);
481 userauth_gssapi(Authctxt *authctxt)
483 Gssctxt *gssctxt = NULL;
484 static gss_OID_set gss_supported = NULL;
485 static u_int mech = 0;
489 /* Try one GSSAPI method at a time, rather than sending them all at
492 if (gss_supported == NULL)
493 gss_indicate_mechs(&min, &gss_supported);
495 /* Check to see if the mechanism is usable before we offer it */
496 while (mech < gss_supported->count && !ok) {
498 ssh_gssapi_delete_ctx(&gssctxt);
499 ssh_gssapi_build_ctx(&gssctxt);
500 ssh_gssapi_set_oid(gssctxt, &gss_supported->elements[mech]);
502 /* My DER encoding requires length<128 */
503 if (gss_supported->elements[mech].length < 128 &&
504 !GSS_ERROR(ssh_gssapi_import_name(gssctxt,
506 ok = 1; /* Mechanism works */
515 authctxt->methoddata=(void *)gssctxt;
517 packet_start(SSH2_MSG_USERAUTH_REQUEST);
518 packet_put_cstring(authctxt->server_user);
519 packet_put_cstring(authctxt->service);
520 packet_put_cstring(authctxt->method->name);
524 packet_put_int((gss_supported->elements[mech].length) + 2);
525 packet_put_char(SSH_GSS_OIDTYPE);
526 packet_put_char(gss_supported->elements[mech].length);
527 packet_put_raw(gss_supported->elements[mech].elements,
528 gss_supported->elements[mech].length);
532 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
533 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
534 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
535 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
537 mech++; /* Move along to next candidate */
543 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
545 Authctxt *authctxt = ctxt;
546 Gssctxt *gssctxt = authctxt->methoddata;
547 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
548 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
549 gss_buffer_desc gssbuf;
550 OM_uint32 status, ms, flags;
553 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
554 recv_tok, &send_tok, &flags);
556 if (send_tok.length > 0) {
557 if (GSS_ERROR(status))
558 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
560 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
562 packet_put_string(send_tok.value, send_tok.length);
564 gss_release_buffer(&ms, &send_tok);
567 if (status == GSS_S_COMPLETE) {
568 /* send either complete or MIC, depending on mechanism */
569 if (!(flags & GSS_C_INTEG_FLAG)) {
570 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
573 ssh_gssapi_buildmic(&b, authctxt->server_user,
574 authctxt->service, "gssapi-with-mic");
576 gssbuf.value = buffer_ptr(&b);
577 gssbuf.length = buffer_len(&b);
579 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
581 if (!GSS_ERROR(status)) {
582 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
583 packet_put_string(mic.value, mic.length);
589 gss_release_buffer(&ms, &mic);
597 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
599 Authctxt *authctxt = ctxt;
604 if (authctxt == NULL)
605 fatal("input_gssapi_response: no authentication context");
606 gssctxt = authctxt->methoddata;
609 oidv = packet_get_string(&oidlen);
612 oidv[0] != SSH_GSS_OIDTYPE ||
613 oidv[1] != oidlen - 2) {
615 debug("Badly encoded mechanism OID received");
616 userauth(authctxt, NULL);
620 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
621 fatal("Server returned different OID than expected");
627 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
628 /* Start again with next method on list */
629 debug("Trying to start again");
630 userauth(authctxt, NULL);
636 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
638 Authctxt *authctxt = ctxt;
639 gss_buffer_desc recv_tok;
643 if (authctxt == NULL)
644 fatal("input_gssapi_response: no authentication context");
646 recv_tok.value = packet_get_string(&slen);
647 recv_tok.length = slen; /* safe typecast */
651 status = process_gssapi_token(ctxt, &recv_tok);
653 xfree(recv_tok.value);
655 if (GSS_ERROR(status)) {
656 /* Start again with the next method in the list */
657 userauth(authctxt, NULL);
663 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
665 Authctxt *authctxt = ctxt;
667 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
668 gss_buffer_desc recv_tok;
669 OM_uint32 status, ms;
672 if (authctxt == NULL)
673 fatal("input_gssapi_response: no authentication context");
674 gssctxt = authctxt->methoddata;
676 recv_tok.value = packet_get_string(&len);
677 recv_tok.length = len;
681 /* Stick it into GSSAPI and see what it says */
682 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
683 &recv_tok, &send_tok, NULL);
685 xfree(recv_tok.value);
686 gss_release_buffer(&ms, &send_tok);
688 /* Server will be returning a failed packet after this one */
692 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
698 maj=packet_get_int();
699 min=packet_get_int();
700 msg=packet_get_string(NULL);
701 lang=packet_get_string(NULL);
705 debug("Server GSSAPI Error:\n%s", msg);
712 userauth_none(Authctxt *authctxt)
714 /* initial userauth request */
715 packet_start(SSH2_MSG_USERAUTH_REQUEST);
716 packet_put_cstring(authctxt->server_user);
717 packet_put_cstring(authctxt->service);
718 packet_put_cstring(authctxt->method->name);
724 userauth_passwd(Authctxt *authctxt)
726 static int attempt = 0;
730 if (attempt++ >= options.number_of_password_prompts)
734 error("Permission denied, please try again.");
736 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
737 authctxt->server_user, authctxt->host);
738 password = read_passphrase(prompt, 0);
739 packet_start(SSH2_MSG_USERAUTH_REQUEST);
740 packet_put_cstring(authctxt->server_user);
741 packet_put_cstring(authctxt->service);
742 packet_put_cstring(authctxt->method->name);
744 packet_put_cstring(password);
745 memset(password, 0, strlen(password));
747 packet_add_padding(64);
750 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
751 &input_userauth_passwd_changereq);
756 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
759 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
761 Authctxt *authctxt = ctxt;
762 char *info, *lang, *password = NULL, *retype = NULL;
765 debug2("input_userauth_passwd_changereq");
767 if (authctxt == NULL)
768 fatal("input_userauth_passwd_changereq: "
769 "no authentication context");
771 info = packet_get_string(NULL);
772 lang = packet_get_string(NULL);
773 if (strlen(info) > 0)
777 packet_start(SSH2_MSG_USERAUTH_REQUEST);
778 packet_put_cstring(authctxt->server_user);
779 packet_put_cstring(authctxt->service);
780 packet_put_cstring(authctxt->method->name);
781 packet_put_char(1); /* additional info */
782 snprintf(prompt, sizeof(prompt),
783 "Enter %.30s@%.128s's old password: ",
784 authctxt->server_user, authctxt->host);
785 password = read_passphrase(prompt, 0);
786 packet_put_cstring(password);
787 memset(password, 0, strlen(password));
790 while (password == NULL) {
791 snprintf(prompt, sizeof(prompt),
792 "Enter %.30s@%.128s's new password: ",
793 authctxt->server_user, authctxt->host);
794 password = read_passphrase(prompt, RP_ALLOW_EOF);
795 if (password == NULL) {
799 snprintf(prompt, sizeof(prompt),
800 "Retype %.30s@%.128s's new password: ",
801 authctxt->server_user, authctxt->host);
802 retype = read_passphrase(prompt, 0);
803 if (strcmp(password, retype) != 0) {
804 memset(password, 0, strlen(password));
806 logit("Mismatch; try again, EOF to quit.");
809 memset(retype, 0, strlen(retype));
812 packet_put_cstring(password);
813 memset(password, 0, strlen(password));
815 packet_add_padding(64);
818 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
819 &input_userauth_passwd_changereq);
823 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
824 u_char *data, u_int datalen)
829 /* the agent supports this key */
831 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
834 * we have already loaded the private key or
835 * the private key is stored in external hardware
837 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
838 return (key_sign(id->key, sigp, lenp, data, datalen));
839 /* load the private key from the file */
840 if ((prv = load_identity_file(id->filename)) == NULL)
842 ret = key_sign(prv, sigp, lenp, data, datalen);
848 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
851 u_char *blob, *signature;
857 debug3("sign_and_send_pubkey");
859 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
860 /* we cannot handle this key */
861 debug3("sign_and_send_pubkey: cannot handle key");
864 /* data to be signed */
866 if (datafellows & SSH_OLD_SESSIONID) {
867 buffer_append(&b, session_id2, session_id2_len);
868 skip = session_id2_len;
870 buffer_put_string(&b, session_id2, session_id2_len);
871 skip = buffer_len(&b);
873 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
874 buffer_put_cstring(&b, authctxt->server_user);
875 buffer_put_cstring(&b,
876 datafellows & SSH_BUG_PKSERVICE ?
879 if (datafellows & SSH_BUG_PKAUTH) {
880 buffer_put_char(&b, have_sig);
882 buffer_put_cstring(&b, authctxt->method->name);
883 buffer_put_char(&b, have_sig);
884 buffer_put_cstring(&b, key_ssh_name(id->key));
886 buffer_put_string(&b, blob, bloblen);
888 /* generate signature */
889 ret = identity_sign(id, &signature, &slen,
890 buffer_ptr(&b), buffer_len(&b));
899 if (datafellows & SSH_BUG_PKSERVICE) {
901 buffer_append(&b, session_id2, session_id2_len);
902 skip = session_id2_len;
903 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
904 buffer_put_cstring(&b, authctxt->server_user);
905 buffer_put_cstring(&b, authctxt->service);
906 buffer_put_cstring(&b, authctxt->method->name);
907 buffer_put_char(&b, have_sig);
908 if (!(datafellows & SSH_BUG_PKAUTH))
909 buffer_put_cstring(&b, key_ssh_name(id->key));
910 buffer_put_string(&b, blob, bloblen);
914 /* append signature */
915 buffer_put_string(&b, signature, slen);
918 /* skip session id and packet type */
919 if (buffer_len(&b) < skip + 1)
920 fatal("userauth_pubkey: internal error");
921 buffer_consume(&b, skip + 1);
923 /* put remaining data from buffer into packet */
924 packet_start(SSH2_MSG_USERAUTH_REQUEST);
925 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
933 send_pubkey_test(Authctxt *authctxt, Identity *id)
936 u_int bloblen, have_sig = 0;
938 debug3("send_pubkey_test");
940 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
941 /* we cannot handle this key */
942 debug3("send_pubkey_test: cannot handle key");
945 /* register callback for USERAUTH_PK_OK message */
946 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
948 packet_start(SSH2_MSG_USERAUTH_REQUEST);
949 packet_put_cstring(authctxt->server_user);
950 packet_put_cstring(authctxt->service);
951 packet_put_cstring(authctxt->method->name);
952 packet_put_char(have_sig);
953 if (!(datafellows & SSH_BUG_PKAUTH))
954 packet_put_cstring(key_ssh_name(id->key));
955 packet_put_string(blob, bloblen);
962 load_identity_file(char *filename)
965 char prompt[300], *passphrase;
969 if (stat(filename, &st) < 0) {
970 debug3("no such identity: %s", filename);
973 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
974 if (private == NULL) {
975 if (options.batch_mode)
977 snprintf(prompt, sizeof prompt,
978 "Enter passphrase for key '%.100s': ", filename);
979 for (i = 0; i < options.number_of_password_prompts; i++) {
980 passphrase = read_passphrase(prompt, 0);
981 if (strcmp(passphrase, "") != 0) {
982 private = key_load_private_type(KEY_UNSPEC, filename,
986 debug2("no passphrase given, try next key");
989 memset(passphrase, 0, strlen(passphrase));
991 if (private != NULL || quit)
993 debug2("bad passphrase given, try again...");
1000 * try keys in the following order:
1001 * 1. agent keys that are found in the config file
1002 * 2. other agent keys
1003 * 3. keys that are only listed in the config file
1006 pubkey_prepare(Authctxt *authctxt)
1009 Idlist agent, files, *preferred;
1011 AuthenticationConnection *ac;
1015 TAILQ_INIT(&agent); /* keys from the agent */
1016 TAILQ_INIT(&files); /* keys from the config file */
1017 preferred = &authctxt->keys;
1018 TAILQ_INIT(preferred); /* preferred order of keys */
1020 /* list of keys stored in the filesystem */
1021 for (i = 0; i < options.num_identity_files; i++) {
1022 key = options.identity_keys[i];
1023 if (key && key->type == KEY_RSA1)
1025 options.identity_keys[i] = NULL;
1026 id = xmalloc(sizeof(*id));
1027 memset(id, 0, sizeof(*id));
1029 id->filename = xstrdup(options.identity_files[i]);
1030 TAILQ_INSERT_TAIL(&files, id, next);
1032 /* list of keys supported by the agent */
1033 if ((ac = ssh_get_authentication_connection())) {
1034 for (key = ssh_get_first_identity(ac, &comment, 2);
1036 key = ssh_get_next_identity(ac, &comment, 2)) {
1038 TAILQ_FOREACH(id, &files, next) {
1039 /* agent keys from the config file are preferred */
1040 if (key_equal(key, id->key)) {
1043 TAILQ_REMOVE(&files, id, next);
1044 TAILQ_INSERT_TAIL(preferred, id, next);
1050 if (!found && !options.identities_only) {
1051 id = xmalloc(sizeof(*id));
1052 memset(id, 0, sizeof(*id));
1054 id->filename = comment;
1056 TAILQ_INSERT_TAIL(&agent, id, next);
1059 /* append remaining agent keys */
1060 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1061 TAILQ_REMOVE(&agent, id, next);
1062 TAILQ_INSERT_TAIL(preferred, id, next);
1064 authctxt->agent = ac;
1066 /* append remaining keys from the config file */
1067 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1068 TAILQ_REMOVE(&files, id, next);
1069 TAILQ_INSERT_TAIL(preferred, id, next);
1071 TAILQ_FOREACH(id, preferred, next) {
1072 debug2("key: %s (%p)", id->filename, id->key);
1077 pubkey_cleanup(Authctxt *authctxt)
1081 if (authctxt->agent != NULL)
1082 ssh_close_authentication_connection(authctxt->agent);
1083 for (id = TAILQ_FIRST(&authctxt->keys); id;
1084 id = TAILQ_FIRST(&authctxt->keys)) {
1085 TAILQ_REMOVE(&authctxt->keys, id, next);
1089 xfree(id->filename);
1095 userauth_pubkey(Authctxt *authctxt)
1100 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1103 /* move key to the end of the queue */
1104 TAILQ_REMOVE(&authctxt->keys, id, next);
1105 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1107 * send a test message if we have the public key. for
1108 * encrypted keys we cannot do this and have to load the
1109 * private key instead
1111 if (id->key && id->key->type != KEY_RSA1) {
1112 debug("Offering public key: %s", id->filename);
1113 sent = send_pubkey_test(authctxt, id);
1114 } else if (id->key == NULL) {
1115 debug("Trying private key: %s", id->filename);
1116 id->key = load_identity_file(id->filename);
1117 if (id->key != NULL) {
1119 sent = sign_and_send_pubkey(authctxt, id);
1131 * Send userauth request message specifying keyboard-interactive method.
1134 userauth_kbdint(Authctxt *authctxt)
1136 static int attempt = 0;
1138 if (attempt++ >= options.number_of_password_prompts)
1140 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1141 if (attempt > 1 && !authctxt->info_req_seen) {
1142 debug3("userauth_kbdint: disable: no info_req_seen");
1143 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1147 debug2("userauth_kbdint");
1148 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1149 packet_put_cstring(authctxt->server_user);
1150 packet_put_cstring(authctxt->service);
1151 packet_put_cstring(authctxt->method->name);
1152 packet_put_cstring(""); /* lang */
1153 packet_put_cstring(options.kbd_interactive_devices ?
1154 options.kbd_interactive_devices : "");
1157 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1162 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1165 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1167 Authctxt *authctxt = ctxt;
1168 char *name, *inst, *lang, *prompt, *response;
1169 u_int num_prompts, i;
1172 debug2("input_userauth_info_req");
1174 if (authctxt == NULL)
1175 fatal("input_userauth_info_req: no authentication context");
1177 authctxt->info_req_seen = 1;
1179 name = packet_get_string(NULL);
1180 inst = packet_get_string(NULL);
1181 lang = packet_get_string(NULL);
1182 if (strlen(name) > 0)
1184 if (strlen(inst) > 0)
1190 num_prompts = packet_get_int();
1192 * Begin to build info response packet based on prompts requested.
1193 * We commit to providing the correct number of responses, so if
1194 * further on we run into a problem that prevents this, we have to
1195 * be sure and clean this up and send a correct error response.
1197 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1198 packet_put_int(num_prompts);
1200 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1201 for (i = 0; i < num_prompts; i++) {
1202 prompt = packet_get_string(NULL);
1203 echo = packet_get_char();
1205 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1207 packet_put_cstring(response);
1208 memset(response, 0, strlen(response));
1212 packet_check_eom(); /* done with parsing incoming message. */
1214 packet_add_padding(64);
1219 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1220 u_char *data, u_int datalen)
1225 int to[2], from[2], status, version = 2;
1227 debug2("ssh_keysign called");
1229 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1230 error("ssh_keysign: no installed: %s", strerror(errno));
1233 if (fflush(stdout) != 0)
1234 error("ssh_keysign: fflush: %s", strerror(errno));
1236 error("ssh_keysign: pipe: %s", strerror(errno));
1239 if (pipe(from) < 0) {
1240 error("ssh_keysign: pipe: %s", strerror(errno));
1243 if ((pid = fork()) < 0) {
1244 error("ssh_keysign: fork: %s", strerror(errno));
1251 if (dup2(from[1], STDOUT_FILENO) < 0)
1252 fatal("ssh_keysign: dup2: %s", strerror(errno));
1254 if (dup2(to[0], STDIN_FILENO) < 0)
1255 fatal("ssh_keysign: dup2: %s", strerror(errno));
1258 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1259 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1266 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1267 buffer_put_string(&b, data, datalen);
1268 if (ssh_msg_send(to[1], version, &b) == -1)
1269 fatal("ssh_keysign: couldn't send request");
1271 if (ssh_msg_recv(from[0], &b) < 0) {
1272 error("ssh_keysign: no reply");
1279 while (waitpid(pid, &status, 0) < 0)
1283 if (buffer_get_char(&b) != version) {
1284 error("ssh_keysign: bad version");
1288 *sigp = buffer_get_string(&b, lenp);
1295 userauth_hostbased(Authctxt *authctxt)
1297 Key *private = NULL;
1298 Sensitive *sensitive = authctxt->sensitive;
1300 u_char *signature, *blob;
1301 char *chost, *pkalg, *p;
1302 const char *service;
1304 int ok, i, len, found = 0;
1306 /* check for a useful key */
1307 for (i = 0; i < sensitive->nkeys; i++) {
1308 private = sensitive->keys[i];
1309 if (private && private->type != KEY_RSA1) {
1311 /* we take and free the key */
1312 sensitive->keys[i] = NULL;
1317 debug("No more client hostkeys for hostbased authentication.");
1320 if (key_to_blob(private, &blob, &blen) == 0) {
1324 /* figure out a name for the client host */
1325 p = get_local_name(packet_get_connection_in());
1327 error("userauth_hostbased: cannot get local ipaddr/name");
1331 len = strlen(p) + 2;
1332 chost = xmalloc(len);
1333 strlcpy(chost, p, len);
1334 strlcat(chost, ".", len);
1335 debug2("userauth_hostbased: chost %s", chost);
1338 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1340 pkalg = xstrdup(key_ssh_name(private));
1342 /* construct data */
1343 buffer_put_string(&b, session_id2, session_id2_len);
1344 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1345 buffer_put_cstring(&b, authctxt->server_user);
1346 buffer_put_cstring(&b, service);
1347 buffer_put_cstring(&b, authctxt->method->name);
1348 buffer_put_cstring(&b, pkalg);
1349 buffer_put_string(&b, blob, blen);
1350 buffer_put_cstring(&b, chost);
1351 buffer_put_cstring(&b, authctxt->local_user);
1355 if (sensitive->external_keysign)
1356 ok = ssh_keysign(private, &signature, &slen,
1357 buffer_ptr(&b), buffer_len(&b));
1359 ok = key_sign(private, &signature, &slen,
1360 buffer_ptr(&b), buffer_len(&b));
1364 error("key_sign failed");
1369 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1370 packet_put_cstring(authctxt->server_user);
1371 packet_put_cstring(authctxt->service);
1372 packet_put_cstring(authctxt->method->name);
1373 packet_put_cstring(pkalg);
1374 packet_put_string(blob, blen);
1375 packet_put_cstring(chost);
1376 packet_put_cstring(authctxt->local_user);
1377 packet_put_string(signature, slen);
1378 memset(signature, 's', slen);
1387 /* find auth method */
1390 * given auth method name, if configurable options permit this method fill
1391 * in auth_ident field and return true, otherwise return false.
1394 authmethod_is_enabled(Authmethod *method)
1398 /* return false if options indicate this method is disabled */
1399 if (method->enabled == NULL || *method->enabled == 0)
1401 /* return false if batch mode is enabled but method needs interactive mode */
1402 if (method->batch_flag != NULL && *method->batch_flag != 0)
1408 authmethod_lookup(const char *name)
1410 Authmethod *method = NULL;
1412 for (method = authmethods; method->name != NULL; method++)
1413 if (strcmp(name, method->name) == 0)
1415 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1419 /* XXX internal state */
1420 static Authmethod *current = NULL;
1421 static char *supported = NULL;
1422 static char *preferred = NULL;
1425 * Given the authentication method list sent by the server, return the
1426 * next method we should try. If the server initially sends a nil list,
1427 * use a built-in default list.
1430 authmethod_get(char *authlist)
1435 /* Use a suitable default if we're passed a nil list. */
1436 if (authlist == NULL || strlen(authlist) == 0)
1437 authlist = options.preferred_authentications;
1439 if (supported == NULL || strcmp(authlist, supported) != 0) {
1440 debug3("start over, passed a different list %s", authlist);
1441 if (supported != NULL)
1443 supported = xstrdup(authlist);
1444 preferred = options.preferred_authentications;
1445 debug3("preferred %s", preferred);
1447 } else if (current != NULL && authmethod_is_enabled(current))
1451 if ((name = match_list(preferred, supported, &next)) == NULL) {
1452 debug("No more authentication methods to try.");
1457 debug3("authmethod_lookup %s", name);
1458 debug3("remaining preferred: %s", preferred);
1459 if ((current = authmethod_lookup(name)) != NULL &&
1460 authmethod_is_enabled(current)) {
1461 debug3("authmethod_is_enabled %s", name);
1462 debug("Next authentication method: %s", name);
1469 authmethods_get(void)
1471 Authmethod *method = NULL;
1476 for (method = authmethods; method->name != NULL; method++) {
1477 if (authmethod_is_enabled(method)) {
1478 if (buffer_len(&b) > 0)
1479 buffer_append(&b, ",", 1);
1480 buffer_append(&b, method->name, strlen(method->name));
1483 buffer_append(&b, "\0", 1);
1484 list = xstrdup(buffer_ptr(&b));