blob: a9490ccfd1f7aefbb8ed7dd5eafa29387e175233 [file] [log] [blame]
Damien Millereba71ba2000-04-29 23:57:08 +10001/*
2 * Copyright (c) 2000 Markus Friedl. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
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.
Damien Millereba71ba2000-04-29 23:57:08 +100012 *
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.
23 */
Damien Millere4340be2000-09-16 13:29:08 +110024
Damien Millereba71ba2000-04-29 23:57:08 +100025#include "includes.h"
Damien Miller3e3b5142003-11-17 21:13:40 +110026RCSID("$OpenBSD: auth2.c,v 1.104 2003/11/04 08:54:09 djm Exp $");
Damien Millereba71ba2000-04-29 23:57:08 +100027
Ben Lindstrom226cfa02001-01-22 05:34:40 +000028#include "ssh2.h"
Damien Millereba71ba2000-04-29 23:57:08 +100029#include "xmalloc.h"
Damien Millereba71ba2000-04-29 23:57:08 +100030#include "packet.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000031#include "log.h"
Damien Millereba71ba2000-04-29 23:57:08 +100032#include "servconf.h"
33#include "compat.h"
Damien Millereba71ba2000-04-29 23:57:08 +100034#include "auth.h"
Damien Millereba71ba2000-04-29 23:57:08 +100035#include "dispatch.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000036#include "pathnames.h"
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000037#include "monitor_wrap.h"
Damien Millereba71ba2000-04-29 23:57:08 +100038
Darren Tucker0efd1552003-08-26 11:49:55 +100039#ifdef GSSAPI
40#include "ssh-gss.h"
41#endif
42
Damien Millereba71ba2000-04-29 23:57:08 +100043/* import */
44extern ServerOptions options;
Ben Lindstrom46c16222000-12-22 01:43:59 +000045extern u_char *session_id2;
Darren Tucker502d3842003-06-28 12:38:01 +100046extern u_int session_id2_len;
Damien Millereba71ba2000-04-29 23:57:08 +100047
Ben Lindstrom511bb242002-06-06 20:52:37 +000048/* methods */
49
50extern Authmethod method_none;
51extern Authmethod method_pubkey;
52extern Authmethod method_passwd;
53extern Authmethod method_kbdint;
54extern Authmethod method_hostbased;
Darren Tucker0efd1552003-08-26 11:49:55 +100055#ifdef GSSAPI
56extern Authmethod method_gssapi;
57#endif
Ben Lindstrom511bb242002-06-06 20:52:37 +000058
59Authmethod *authmethods[] = {
60 &method_none,
61 &method_pubkey,
Darren Tucker0efd1552003-08-26 11:49:55 +100062#ifdef GSSAPI
63 &method_gssapi,
64#endif
Ben Lindstrom511bb242002-06-06 20:52:37 +000065 &method_passwd,
66 &method_kbdint,
67 &method_hostbased,
68 NULL
Damien Miller874d77b2000-10-14 16:23:11 +110069};
70
Damien Millereba71ba2000-04-29 23:57:08 +100071/* protocol */
72
Damien Miller630d6f42002-01-22 23:17:30 +110073static void input_service_request(int, u_int32_t, void *);
74static void input_userauth_request(int, u_int32_t, void *);
Damien Millereba71ba2000-04-29 23:57:08 +100075
Damien Millereba71ba2000-04-29 23:57:08 +100076/* helper */
Ben Lindstrombba81212001-06-25 05:01:22 +000077static Authmethod *authmethod_lookup(const char *);
Ben Lindstrom79073822001-07-04 03:42:30 +000078static char *authmethods_get(void);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000079int user_key_allowed(struct passwd *, Key *);
Damien Millereba71ba2000-04-29 23:57:08 +100080
Damien Millereba71ba2000-04-29 23:57:08 +100081/*
Damien Miller874d77b2000-10-14 16:23:11 +110082 * loop until authctxt->success == TRUE
Damien Millereba71ba2000-04-29 23:57:08 +100083 */
84
Darren Tucker3e33cec2003-10-02 16:12:36 +100085void
86do_authentication2(Authctxt *authctxt)
Damien Millereba71ba2000-04-29 23:57:08 +100087{
Ben Lindstrombdfb4df2001-10-03 17:12:43 +000088 /* challenge-response is implemented via keyboard interactive */
Ben Lindstrom551ea372001-06-05 18:56:16 +000089 if (options.challenge_response_authentication)
Ben Lindstrom95fb2dd2001-01-23 03:12:10 +000090 options.kbd_interactive_authentication = 1;
91
Damien Miller7d053392002-01-22 23:24:13 +110092 dispatch_init(&dispatch_protocol_error);
Damien Millereba71ba2000-04-29 23:57:08 +100093 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
Damien Miller874d77b2000-10-14 16:23:11 +110094 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
Damien Millereba71ba2000-04-29 23:57:08 +100095}
96
Ben Lindstrombba81212001-06-25 05:01:22 +000097static void
Damien Miller630d6f42002-01-22 23:17:30 +110098input_service_request(int type, u_int32_t seq, void *ctxt)
Damien Millereba71ba2000-04-29 23:57:08 +100099{
Damien Miller874d77b2000-10-14 16:23:11 +1100100 Authctxt *authctxt = ctxt;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000101 u_int len;
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000102 int acceptit = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000103 char *service = packet_get_string(&len);
Damien Miller48b03fc2002-01-22 23:11:40 +1100104 packet_check_eom();
Damien Millereba71ba2000-04-29 23:57:08 +1000105
Damien Miller874d77b2000-10-14 16:23:11 +1100106 if (authctxt == NULL)
107 fatal("input_service_request: no authctxt");
108
Damien Millereba71ba2000-04-29 23:57:08 +1000109 if (strcmp(service, "ssh-userauth") == 0) {
Damien Miller874d77b2000-10-14 16:23:11 +1100110 if (!authctxt->success) {
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000111 acceptit = 1;
Damien Millereba71ba2000-04-29 23:57:08 +1000112 /* now we can handle user-auth requests */
113 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
114 }
115 }
116 /* XXX all other service requests are denied */
117
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000118 if (acceptit) {
Damien Millereba71ba2000-04-29 23:57:08 +1000119 packet_start(SSH2_MSG_SERVICE_ACCEPT);
120 packet_put_cstring(service);
121 packet_send();
122 packet_write_wait();
123 } else {
124 debug("bad service request %s", service);
125 packet_disconnect("bad service request %s", service);
126 }
127 xfree(service);
128}
129
Ben Lindstrombba81212001-06-25 05:01:22 +0000130static void
Damien Miller630d6f42002-01-22 23:17:30 +1100131input_userauth_request(int type, u_int32_t seq, void *ctxt)
Damien Millereba71ba2000-04-29 23:57:08 +1000132{
Damien Miller874d77b2000-10-14 16:23:11 +1100133 Authctxt *authctxt = ctxt;
134 Authmethod *m = NULL;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000135 char *user, *service, *method, *style = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000136 int authenticated = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000137
Damien Miller874d77b2000-10-14 16:23:11 +1100138 if (authctxt == NULL)
139 fatal("input_userauth_request: no authctxt");
Damien Millereba71ba2000-04-29 23:57:08 +1000140
Damien Miller874d77b2000-10-14 16:23:11 +1100141 user = packet_get_string(NULL);
142 service = packet_get_string(NULL);
143 method = packet_get_string(NULL);
144 debug("userauth-request for user %s service %s method %s", user, service, method);
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000145 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
Damien Miller874d77b2000-10-14 16:23:11 +1100146
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000147 if ((style = strchr(user, ':')) != NULL)
148 *style++ = 0;
149
Kevin Stevesef4eea92001-02-05 12:42:17 +0000150 if (authctxt->attempt++ == 0) {
Damien Miller3a5b0232002-03-13 13:19:42 +1100151 /* setup auth context */
Kevin Steves205cc1e2002-03-22 20:43:05 +0000152 authctxt->pw = PRIVSEP(getpwnamallow(user));
153 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
Damien Miller874d77b2000-10-14 16:23:11 +1100154 authctxt->valid = 1;
155 debug2("input_userauth_request: setting up authctxt for %s", user);
156#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +1000157 if (options.use_pam)
158 PRIVSEP(start_pam(authctxt->pw->pw_name));
Damien Miller874d77b2000-10-14 16:23:11 +1100159#endif
160 } else {
Damien Miller996acd22003-04-09 20:59:48 +1000161 logit("input_userauth_request: illegal user %s", user);
Damien Miller856f0be2003-09-03 07:32:45 +1000162 authctxt->pw = fakepw();
Damien Miller22e22bf2001-01-19 15:46:38 +1100163#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +1000164 if (options.use_pam)
165 PRIVSEP(start_pam(user));
Damien Miller22e22bf2001-01-19 15:46:38 +1100166#endif
Damien Miller874d77b2000-10-14 16:23:11 +1100167 }
Ben Lindstrom7ebb6352002-03-22 03:04:08 +0000168 setproctitle("%s%s", authctxt->pw ? user : "unknown",
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000169 use_privsep ? " [net]" : "");
Damien Miller874d77b2000-10-14 16:23:11 +1100170 authctxt->user = xstrdup(user);
171 authctxt->service = xstrdup(service);
Ben Lindstrom9d0c0662001-06-09 01:40:00 +0000172 authctxt->style = style ? xstrdup(style) : NULL;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000173 if (use_privsep)
174 mm_inform_authserv(service, style);
Ben Lindstrom9d0c0662001-06-09 01:40:00 +0000175 } else if (strcmp(user, authctxt->user) != 0 ||
176 strcmp(service, authctxt->service) != 0) {
177 packet_disconnect("Change of username or service not allowed: "
178 "(%s,%s) -> (%s,%s)",
179 authctxt->user, authctxt->service, user, service);
Damien Millereba71ba2000-04-29 23:57:08 +1000180 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000181 /* reset state */
Damien Milleree116252001-12-21 12:42:34 +1100182 auth2_challenge_stop(authctxt);
Darren Tucker0efd1552003-08-26 11:49:55 +1000183
184#ifdef GSSAPI
185 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
186 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
187#endif
188
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000189 authctxt->postponed = 0;
Damien Millerb70b61f2000-09-16 16:25:12 +1100190
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000191 /* try to authenticate user */
Damien Miller874d77b2000-10-14 16:23:11 +1100192 m = authmethod_lookup(method);
193 if (m != NULL) {
194 debug2("input_userauth_request: try method %s", method);
195 authenticated = m->userauth(authctxt);
Damien Miller874d77b2000-10-14 16:23:11 +1100196 }
Damien Miller5d57e502001-03-30 10:48:31 +1000197 userauth_finish(authctxt, authenticated, method);
198
199 xfree(service);
200 xfree(user);
201 xfree(method);
202}
203
204void
205userauth_finish(Authctxt *authctxt, int authenticated, char *method)
206{
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000207 char *methods;
208
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000209 if (!authctxt->valid && authenticated)
210 fatal("INTERNAL ERROR: authenticated invalid user %s",
211 authctxt->user);
Damien Millerb70b61f2000-09-16 16:25:12 +1100212
Damien Miller874d77b2000-10-14 16:23:11 +1100213 /* Special handling for root */
Damien Miller556f9312003-02-24 11:59:26 +1100214 if (authenticated && authctxt->pw->pw_uid == 0 &&
Ben Lindstromd8a90212001-02-15 03:08:27 +0000215 !auth_root_allowed(method))
Damien Millereba71ba2000-04-29 23:57:08 +1000216 authenticated = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000217
Damien Miller1f499fd2003-08-25 13:08:49 +1000218#ifdef USE_PAM
219 if (options.use_pam && authenticated && !PRIVSEP(do_pam_account()))
220 authenticated = 0;
221#endif
222
Tim Rice81ed5182002-09-25 17:38:46 -0700223#ifdef _UNICOS
224 if (authenticated && cray_access_denied(authctxt->user)) {
225 authenticated = 0;
226 fatal("Access denied for user %s.",authctxt->user);
227 }
228#endif /* _UNICOS */
229
Damien Miller874d77b2000-10-14 16:23:11 +1100230 /* Log before sending the reply */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000231 auth_log(authctxt, authenticated, method, " ssh2");
232
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000233 if (authctxt->postponed)
234 return;
235
236 /* XXX todo: check if multiple auth methods are needed */
237 if (authenticated == 1) {
238 /* turn off userauth */
Damien Miller7d053392002-01-22 23:24:13 +1100239 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000240 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
241 packet_send();
242 packet_write_wait();
243 /* now we can break out */
244 authctxt->success = 1;
245 } else {
Ben Lindstromf50ad1f2003-04-27 18:44:31 +0000246 if (authctxt->failures++ > AUTH_FAIL_MAX)
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000247 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
248 methods = authmethods_get();
249 packet_start(SSH2_MSG_USERAUTH_FAILURE);
250 packet_put_cstring(methods);
251 packet_put_char(0); /* XXX partial success, unused */
252 packet_send();
253 packet_write_wait();
254 xfree(methods);
255 }
Damien Miller874d77b2000-10-14 16:23:11 +1100256}
257
Damien Miller874d77b2000-10-14 16:23:11 +1100258#define DELIM ","
Damien Millereba71ba2000-04-29 23:57:08 +1000259
Ben Lindstrom79073822001-07-04 03:42:30 +0000260static char *
Damien Miller874d77b2000-10-14 16:23:11 +1100261authmethods_get(void)
262{
Damien Miller0e3b8722002-01-22 23:26:38 +1100263 Buffer b;
Damien Miller874d77b2000-10-14 16:23:11 +1100264 char *list;
Ben Lindstrom511bb242002-06-06 20:52:37 +0000265 int i;
Damien Miller874d77b2000-10-14 16:23:11 +1100266
Damien Miller0e3b8722002-01-22 23:26:38 +1100267 buffer_init(&b);
Ben Lindstrom511bb242002-06-06 20:52:37 +0000268 for (i = 0; authmethods[i] != NULL; i++) {
269 if (strcmp(authmethods[i]->name, "none") == 0)
Damien Miller874d77b2000-10-14 16:23:11 +1100270 continue;
Ben Lindstrom511bb242002-06-06 20:52:37 +0000271 if (authmethods[i]->enabled != NULL &&
272 *(authmethods[i]->enabled) != 0) {
Damien Miller0e3b8722002-01-22 23:26:38 +1100273 if (buffer_len(&b) > 0)
274 buffer_append(&b, ",", 1);
Ben Lindstrom511bb242002-06-06 20:52:37 +0000275 buffer_append(&b, authmethods[i]->name,
276 strlen(authmethods[i]->name));
Damien Millereba71ba2000-04-29 23:57:08 +1000277 }
278 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100279 buffer_append(&b, "\0", 1);
280 list = xstrdup(buffer_ptr(&b));
281 buffer_free(&b);
Damien Miller874d77b2000-10-14 16:23:11 +1100282 return list;
283}
284
Ben Lindstrombba81212001-06-25 05:01:22 +0000285static Authmethod *
Damien Miller874d77b2000-10-14 16:23:11 +1100286authmethod_lookup(const char *name)
287{
Ben Lindstrom511bb242002-06-06 20:52:37 +0000288 int i;
289
Damien Miller874d77b2000-10-14 16:23:11 +1100290 if (name != NULL)
Ben Lindstrom511bb242002-06-06 20:52:37 +0000291 for (i = 0; authmethods[i] != NULL; i++)
292 if (authmethods[i]->enabled != NULL &&
293 *(authmethods[i]->enabled) != 0 &&
294 strcmp(name, authmethods[i]->name) == 0)
295 return authmethods[i];
296 debug2("Unrecognized authentication method name: %s",
297 name ? name : "NULL");
Damien Miller874d77b2000-10-14 16:23:11 +1100298 return NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000299}