blob: efff03a524c1956325a734bcfd4f762898c19f69 [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"
Darren Tucker1e66a392003-08-26 12:08:15 +100026RCSID("$OpenBSD: auth2.c,v 1.101 2003/08/22 13:22:27 markus 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 Lindstrom7a2073c2002-03-22 02:30:41 +000048Authctxt *x_authctxt = NULL;
Damien Miller874d77b2000-10-14 16:23:11 +110049
Ben Lindstrom511bb242002-06-06 20:52:37 +000050/* methods */
51
52extern Authmethod method_none;
53extern Authmethod method_pubkey;
54extern Authmethod method_passwd;
55extern Authmethod method_kbdint;
56extern Authmethod method_hostbased;
Darren Tucker0efd1552003-08-26 11:49:55 +100057#ifdef GSSAPI
58extern Authmethod method_gssapi;
59#endif
Ben Lindstrom511bb242002-06-06 20:52:37 +000060
61Authmethod *authmethods[] = {
62 &method_none,
63 &method_pubkey,
Darren Tucker0efd1552003-08-26 11:49:55 +100064#ifdef GSSAPI
65 &method_gssapi,
66#endif
Ben Lindstrom511bb242002-06-06 20:52:37 +000067 &method_passwd,
68 &method_kbdint,
69 &method_hostbased,
70 NULL
Damien Miller874d77b2000-10-14 16:23:11 +110071};
72
Damien Millereba71ba2000-04-29 23:57:08 +100073/* protocol */
74
Damien Miller630d6f42002-01-22 23:17:30 +110075static void input_service_request(int, u_int32_t, void *);
76static void input_userauth_request(int, u_int32_t, void *);
Damien Millereba71ba2000-04-29 23:57:08 +100077
Damien Millereba71ba2000-04-29 23:57:08 +100078/* helper */
Ben Lindstrombba81212001-06-25 05:01:22 +000079static Authmethod *authmethod_lookup(const char *);
Ben Lindstrom79073822001-07-04 03:42:30 +000080static char *authmethods_get(void);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000081int user_key_allowed(struct passwd *, Key *);
82int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
Damien Millereba71ba2000-04-29 23:57:08 +100083
Damien Millereba71ba2000-04-29 23:57:08 +100084/*
Damien Miller874d77b2000-10-14 16:23:11 +110085 * loop until authctxt->success == TRUE
Damien Millereba71ba2000-04-29 23:57:08 +100086 */
87
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +000088Authctxt *
Ben Lindstrom3c36bb22001-12-06 17:55:26 +000089do_authentication2(void)
Damien Millereba71ba2000-04-29 23:57:08 +100090{
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000091 Authctxt *authctxt = authctxt_new();
92
Damien Miller874d77b2000-10-14 16:23:11 +110093 x_authctxt = authctxt; /*XXX*/
94
Ben Lindstrombdfb4df2001-10-03 17:12:43 +000095 /* challenge-response is implemented via keyboard interactive */
Ben Lindstrom551ea372001-06-05 18:56:16 +000096 if (options.challenge_response_authentication)
Ben Lindstrom95fb2dd2001-01-23 03:12:10 +000097 options.kbd_interactive_authentication = 1;
98
Damien Miller7d053392002-01-22 23:24:13 +110099 dispatch_init(&dispatch_protocol_error);
Damien Millereba71ba2000-04-29 23:57:08 +1000100 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
Damien Miller874d77b2000-10-14 16:23:11 +1100101 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +0000102
103 return (authctxt);
Damien Millereba71ba2000-04-29 23:57:08 +1000104}
105
Ben Lindstrombba81212001-06-25 05:01:22 +0000106static void
Damien Miller630d6f42002-01-22 23:17:30 +1100107input_service_request(int type, u_int32_t seq, void *ctxt)
Damien Millereba71ba2000-04-29 23:57:08 +1000108{
Damien Miller874d77b2000-10-14 16:23:11 +1100109 Authctxt *authctxt = ctxt;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000110 u_int len;
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000111 int acceptit = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000112 char *service = packet_get_string(&len);
Damien Miller48b03fc2002-01-22 23:11:40 +1100113 packet_check_eom();
Damien Millereba71ba2000-04-29 23:57:08 +1000114
Damien Miller874d77b2000-10-14 16:23:11 +1100115 if (authctxt == NULL)
116 fatal("input_service_request: no authctxt");
117
Damien Millereba71ba2000-04-29 23:57:08 +1000118 if (strcmp(service, "ssh-userauth") == 0) {
Damien Miller874d77b2000-10-14 16:23:11 +1100119 if (!authctxt->success) {
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000120 acceptit = 1;
Damien Millereba71ba2000-04-29 23:57:08 +1000121 /* now we can handle user-auth requests */
122 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
123 }
124 }
125 /* XXX all other service requests are denied */
126
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000127 if (acceptit) {
Damien Millereba71ba2000-04-29 23:57:08 +1000128 packet_start(SSH2_MSG_SERVICE_ACCEPT);
129 packet_put_cstring(service);
130 packet_send();
131 packet_write_wait();
132 } else {
133 debug("bad service request %s", service);
134 packet_disconnect("bad service request %s", service);
135 }
136 xfree(service);
137}
138
Ben Lindstrombba81212001-06-25 05:01:22 +0000139static void
Damien Miller630d6f42002-01-22 23:17:30 +1100140input_userauth_request(int type, u_int32_t seq, void *ctxt)
Damien Millereba71ba2000-04-29 23:57:08 +1000141{
Damien Miller874d77b2000-10-14 16:23:11 +1100142 Authctxt *authctxt = ctxt;
143 Authmethod *m = NULL;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000144 char *user, *service, *method, *style = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000145 int authenticated = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000146
Damien Miller874d77b2000-10-14 16:23:11 +1100147 if (authctxt == NULL)
148 fatal("input_userauth_request: no authctxt");
Damien Millereba71ba2000-04-29 23:57:08 +1000149
Damien Miller874d77b2000-10-14 16:23:11 +1100150 user = packet_get_string(NULL);
151 service = packet_get_string(NULL);
152 method = packet_get_string(NULL);
153 debug("userauth-request for user %s service %s method %s", user, service, method);
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000154 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
Damien Miller874d77b2000-10-14 16:23:11 +1100155
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000156 if ((style = strchr(user, ':')) != NULL)
157 *style++ = 0;
158
Kevin Stevesef4eea92001-02-05 12:42:17 +0000159 if (authctxt->attempt++ == 0) {
Damien Miller3a5b0232002-03-13 13:19:42 +1100160 /* setup auth context */
Kevin Steves205cc1e2002-03-22 20:43:05 +0000161 authctxt->pw = PRIVSEP(getpwnamallow(user));
162 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
Damien Miller874d77b2000-10-14 16:23:11 +1100163 authctxt->valid = 1;
164 debug2("input_userauth_request: setting up authctxt for %s", user);
165#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +1000166 if (options.use_pam)
167 PRIVSEP(start_pam(authctxt->pw->pw_name));
Damien Miller874d77b2000-10-14 16:23:11 +1100168#endif
169 } else {
Damien Miller996acd22003-04-09 20:59:48 +1000170 logit("input_userauth_request: illegal user %s", user);
Damien Miller22e22bf2001-01-19 15:46:38 +1100171#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +1000172 if (options.use_pam)
173 PRIVSEP(start_pam(user));
Damien Miller22e22bf2001-01-19 15:46:38 +1100174#endif
Damien Miller874d77b2000-10-14 16:23:11 +1100175 }
Ben Lindstrom7ebb6352002-03-22 03:04:08 +0000176 setproctitle("%s%s", authctxt->pw ? user : "unknown",
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000177 use_privsep ? " [net]" : "");
Damien Miller874d77b2000-10-14 16:23:11 +1100178 authctxt->user = xstrdup(user);
179 authctxt->service = xstrdup(service);
Ben Lindstrom9d0c0662001-06-09 01:40:00 +0000180 authctxt->style = style ? xstrdup(style) : NULL;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000181 if (use_privsep)
182 mm_inform_authserv(service, style);
Ben Lindstrom9d0c0662001-06-09 01:40:00 +0000183 } else if (strcmp(user, authctxt->user) != 0 ||
184 strcmp(service, authctxt->service) != 0) {
185 packet_disconnect("Change of username or service not allowed: "
186 "(%s,%s) -> (%s,%s)",
187 authctxt->user, authctxt->service, user, service);
Damien Millereba71ba2000-04-29 23:57:08 +1000188 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000189 /* reset state */
Damien Milleree116252001-12-21 12:42:34 +1100190 auth2_challenge_stop(authctxt);
Darren Tucker0efd1552003-08-26 11:49:55 +1000191
192#ifdef GSSAPI
193 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
194 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
195#endif
196
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000197 authctxt->postponed = 0;
Damien Millerb70b61f2000-09-16 16:25:12 +1100198
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000199 /* try to authenticate user */
Damien Miller874d77b2000-10-14 16:23:11 +1100200 m = authmethod_lookup(method);
201 if (m != NULL) {
202 debug2("input_userauth_request: try method %s", method);
203 authenticated = m->userauth(authctxt);
Damien Miller874d77b2000-10-14 16:23:11 +1100204 }
Damien Miller5d57e502001-03-30 10:48:31 +1000205 userauth_finish(authctxt, authenticated, method);
206
207 xfree(service);
208 xfree(user);
209 xfree(method);
210}
211
212void
213userauth_finish(Authctxt *authctxt, int authenticated, char *method)
214{
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000215 char *methods;
216
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000217 if (!authctxt->valid && authenticated)
218 fatal("INTERNAL ERROR: authenticated invalid user %s",
219 authctxt->user);
Damien Millerb70b61f2000-09-16 16:25:12 +1100220
Damien Miller874d77b2000-10-14 16:23:11 +1100221 /* Special handling for root */
Damien Miller556f9312003-02-24 11:59:26 +1100222 if (authenticated && authctxt->pw->pw_uid == 0 &&
Ben Lindstromd8a90212001-02-15 03:08:27 +0000223 !auth_root_allowed(method))
Damien Millereba71ba2000-04-29 23:57:08 +1000224 authenticated = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000225
Damien Miller1f499fd2003-08-25 13:08:49 +1000226#ifdef USE_PAM
227 if (options.use_pam && authenticated && !PRIVSEP(do_pam_account()))
228 authenticated = 0;
229#endif
230
Tim Rice81ed5182002-09-25 17:38:46 -0700231#ifdef _UNICOS
232 if (authenticated && cray_access_denied(authctxt->user)) {
233 authenticated = 0;
234 fatal("Access denied for user %s.",authctxt->user);
235 }
236#endif /* _UNICOS */
237
Damien Miller874d77b2000-10-14 16:23:11 +1100238 /* Log before sending the reply */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000239 auth_log(authctxt, authenticated, method, " ssh2");
240
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000241 if (authctxt->postponed)
242 return;
243
244 /* XXX todo: check if multiple auth methods are needed */
245 if (authenticated == 1) {
246 /* turn off userauth */
Damien Miller7d053392002-01-22 23:24:13 +1100247 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000248 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
249 packet_send();
250 packet_write_wait();
251 /* now we can break out */
252 authctxt->success = 1;
253 } else {
Ben Lindstromf50ad1f2003-04-27 18:44:31 +0000254 if (authctxt->failures++ > AUTH_FAIL_MAX)
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000255 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
256 methods = authmethods_get();
257 packet_start(SSH2_MSG_USERAUTH_FAILURE);
258 packet_put_cstring(methods);
259 packet_put_char(0); /* XXX partial success, unused */
260 packet_send();
261 packet_write_wait();
262 xfree(methods);
263 }
Damien Miller874d77b2000-10-14 16:23:11 +1100264}
265
Damien Miller874d77b2000-10-14 16:23:11 +1100266/* get current user */
Damien Millereba71ba2000-04-29 23:57:08 +1000267
268struct passwd*
269auth_get_user(void)
270{
Damien Miller874d77b2000-10-14 16:23:11 +1100271 return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000272}
273
Damien Miller874d77b2000-10-14 16:23:11 +1100274#define DELIM ","
Damien Millereba71ba2000-04-29 23:57:08 +1000275
Ben Lindstrom79073822001-07-04 03:42:30 +0000276static char *
Damien Miller874d77b2000-10-14 16:23:11 +1100277authmethods_get(void)
278{
Damien Miller0e3b8722002-01-22 23:26:38 +1100279 Buffer b;
Damien Miller874d77b2000-10-14 16:23:11 +1100280 char *list;
Ben Lindstrom511bb242002-06-06 20:52:37 +0000281 int i;
Damien Miller874d77b2000-10-14 16:23:11 +1100282
Damien Miller0e3b8722002-01-22 23:26:38 +1100283 buffer_init(&b);
Ben Lindstrom511bb242002-06-06 20:52:37 +0000284 for (i = 0; authmethods[i] != NULL; i++) {
285 if (strcmp(authmethods[i]->name, "none") == 0)
Damien Miller874d77b2000-10-14 16:23:11 +1100286 continue;
Ben Lindstrom511bb242002-06-06 20:52:37 +0000287 if (authmethods[i]->enabled != NULL &&
288 *(authmethods[i]->enabled) != 0) {
Damien Miller0e3b8722002-01-22 23:26:38 +1100289 if (buffer_len(&b) > 0)
290 buffer_append(&b, ",", 1);
Ben Lindstrom511bb242002-06-06 20:52:37 +0000291 buffer_append(&b, authmethods[i]->name,
292 strlen(authmethods[i]->name));
Damien Millereba71ba2000-04-29 23:57:08 +1000293 }
294 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100295 buffer_append(&b, "\0", 1);
296 list = xstrdup(buffer_ptr(&b));
297 buffer_free(&b);
Damien Miller874d77b2000-10-14 16:23:11 +1100298 return list;
299}
300
Ben Lindstrombba81212001-06-25 05:01:22 +0000301static Authmethod *
Damien Miller874d77b2000-10-14 16:23:11 +1100302authmethod_lookup(const char *name)
303{
Ben Lindstrom511bb242002-06-06 20:52:37 +0000304 int i;
305
Damien Miller874d77b2000-10-14 16:23:11 +1100306 if (name != NULL)
Ben Lindstrom511bb242002-06-06 20:52:37 +0000307 for (i = 0; authmethods[i] != NULL; i++)
308 if (authmethods[i]->enabled != NULL &&
309 *(authmethods[i]->enabled) != 0 &&
310 strcmp(name, authmethods[i]->name) == 0)
311 return authmethods[i];
312 debug2("Unrecognized authentication method name: %s",
313 name ? name : "NULL");
Damien Miller874d77b2000-10-14 16:23:11 +1100314 return NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000315}