blob: 3377fde8b1b7c2924f2012ea1c65f5ee2eccc081 [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"
Ben Lindstrom7ebb6352002-03-22 03:04:08 +000026RCSID("$OpenBSD: auth2.c,v 1.89 2002/03/19 14:27:39 markus Exp $");
Damien Miller874d77b2000-10-14 16:23:11 +110027
Damien Millereba71ba2000-04-29 23:57:08 +100028#include <openssl/evp.h>
29
Ben Lindstrom226cfa02001-01-22 05:34:40 +000030#include "ssh2.h"
Damien Millereba71ba2000-04-29 23:57:08 +100031#include "xmalloc.h"
32#include "rsa.h"
Ben Lindstromd95c09c2001-02-18 19:13:33 +000033#include "sshpty.h"
Damien Millereba71ba2000-04-29 23:57:08 +100034#include "packet.h"
35#include "buffer.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000036#include "log.h"
Damien Millereba71ba2000-04-29 23:57:08 +100037#include "servconf.h"
38#include "compat.h"
Ben Lindstromc7637672001-06-09 00:36:26 +000039#include "channels.h"
Damien Millereba71ba2000-04-29 23:57:08 +100040#include "bufaux.h"
Damien Millereba71ba2000-04-29 23:57:08 +100041#include "auth.h"
42#include "session.h"
43#include "dispatch.h"
Damien Millereba71ba2000-04-29 23:57:08 +100044#include "key.h"
Ben Lindstrom6d40c0f2001-01-29 09:02:24 +000045#include "cipher.h"
Damien Millereba71ba2000-04-29 23:57:08 +100046#include "kex.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000047#include "pathnames.h"
Damien Millereba71ba2000-04-29 23:57:08 +100048#include "uidswap.h"
Damien Millerf6d9e222000-06-18 14:50:44 +100049#include "auth-options.h"
Ben Lindstrom5eabda32001-04-12 23:34:34 +000050#include "hostfile.h"
51#include "canohost.h"
Ben Lindstrom551ea372001-06-05 18:56:16 +000052#include "match.h"
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000053#include "monitor_wrap.h"
Damien Millereba71ba2000-04-29 23:57:08 +100054
55/* import */
56extern ServerOptions options;
Ben Lindstrom46c16222000-12-22 01:43:59 +000057extern u_char *session_id2;
Damien Millereba71ba2000-04-29 23:57:08 +100058extern int session_id2_len;
59
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000060Authctxt *x_authctxt = NULL;
Damien Miller874d77b2000-10-14 16:23:11 +110061static int one = 1;
62
63typedef struct Authmethod Authmethod;
64struct Authmethod {
65 char *name;
66 int (*userauth)(Authctxt *authctxt);
67 int *enabled;
68};
69
Damien Millereba71ba2000-04-29 23:57:08 +100070/* protocol */
71
Damien Miller630d6f42002-01-22 23:17:30 +110072static void input_service_request(int, u_int32_t, void *);
73static void input_userauth_request(int, u_int32_t, void *);
Damien Millereba71ba2000-04-29 23:57:08 +100074
Damien Millereba71ba2000-04-29 23:57:08 +100075/* helper */
Ben Lindstrombba81212001-06-25 05:01:22 +000076static Authmethod *authmethod_lookup(const char *);
Ben Lindstrom79073822001-07-04 03:42:30 +000077static char *authmethods_get(void);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000078int user_key_allowed(struct passwd *, Key *);
79int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
Damien Millereba71ba2000-04-29 23:57:08 +100080
Damien Miller874d77b2000-10-14 16:23:11 +110081/* auth */
Ben Lindstrombba81212001-06-25 05:01:22 +000082static void userauth_banner(void);
83static int userauth_none(Authctxt *);
84static int userauth_passwd(Authctxt *);
85static int userauth_pubkey(Authctxt *);
86static int userauth_hostbased(Authctxt *);
87static int userauth_kbdint(Authctxt *);
Damien Miller874d77b2000-10-14 16:23:11 +110088
89Authmethod authmethods[] = {
90 {"none",
91 userauth_none,
92 &one},
93 {"publickey",
94 userauth_pubkey,
Damien Miller0bc1bd82000-11-13 22:57:25 +110095 &options.pubkey_authentication},
Damien Miller874d77b2000-10-14 16:23:11 +110096 {"password",
97 userauth_passwd,
98 &options.password_authentication},
Ben Lindstromd1f20ec2001-02-10 21:31:53 +000099 {"keyboard-interactive",
100 userauth_kbdint,
101 &options.kbd_interactive_authentication},
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000102 {"hostbased",
103 userauth_hostbased,
104 &options.hostbased_authentication},
Damien Miller874d77b2000-10-14 16:23:11 +1100105 {NULL, NULL, NULL}
Damien Millereba71ba2000-04-29 23:57:08 +1000106};
Damien Millereba71ba2000-04-29 23:57:08 +1000107
108/*
Damien Miller874d77b2000-10-14 16:23:11 +1100109 * loop until authctxt->success == TRUE
Damien Millereba71ba2000-04-29 23:57:08 +1000110 */
111
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +0000112Authctxt *
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000113do_authentication2(void)
Damien Millereba71ba2000-04-29 23:57:08 +1000114{
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000115 Authctxt *authctxt = authctxt_new();
116
Damien Miller874d77b2000-10-14 16:23:11 +1100117 x_authctxt = authctxt; /*XXX*/
118
Ben Lindstrombdfb4df2001-10-03 17:12:43 +0000119 /* challenge-response is implemented via keyboard interactive */
Ben Lindstrom551ea372001-06-05 18:56:16 +0000120 if (options.challenge_response_authentication)
Ben Lindstrom95fb2dd2001-01-23 03:12:10 +0000121 options.kbd_interactive_authentication = 1;
Damien Millerf8154422001-04-25 22:44:14 +1000122 if (options.pam_authentication_via_kbd_int)
123 options.kbd_interactive_authentication = 1;
Ben Lindstrom95fb2dd2001-01-23 03:12:10 +0000124
Damien Miller7d053392002-01-22 23:24:13 +1100125 dispatch_init(&dispatch_protocol_error);
Damien Millereba71ba2000-04-29 23:57:08 +1000126 dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
Damien Miller874d77b2000-10-14 16:23:11 +1100127 dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +0000128
129 return (authctxt);
Damien Millereba71ba2000-04-29 23:57:08 +1000130}
131
Ben Lindstrombba81212001-06-25 05:01:22 +0000132static void
Damien Miller630d6f42002-01-22 23:17:30 +1100133input_service_request(int type, u_int32_t seq, void *ctxt)
Damien Millereba71ba2000-04-29 23:57:08 +1000134{
Damien Miller874d77b2000-10-14 16:23:11 +1100135 Authctxt *authctxt = ctxt;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000136 u_int len;
Damien Millereba71ba2000-04-29 23:57:08 +1000137 int accept = 0;
138 char *service = packet_get_string(&len);
Damien Miller48b03fc2002-01-22 23:11:40 +1100139 packet_check_eom();
Damien Millereba71ba2000-04-29 23:57:08 +1000140
Damien Miller874d77b2000-10-14 16:23:11 +1100141 if (authctxt == NULL)
142 fatal("input_service_request: no authctxt");
143
Damien Millereba71ba2000-04-29 23:57:08 +1000144 if (strcmp(service, "ssh-userauth") == 0) {
Damien Miller874d77b2000-10-14 16:23:11 +1100145 if (!authctxt->success) {
Damien Millereba71ba2000-04-29 23:57:08 +1000146 accept = 1;
147 /* now we can handle user-auth requests */
148 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
149 }
150 }
151 /* XXX all other service requests are denied */
152
153 if (accept) {
154 packet_start(SSH2_MSG_SERVICE_ACCEPT);
155 packet_put_cstring(service);
156 packet_send();
157 packet_write_wait();
158 } else {
159 debug("bad service request %s", service);
160 packet_disconnect("bad service request %s", service);
161 }
162 xfree(service);
163}
164
Ben Lindstrombba81212001-06-25 05:01:22 +0000165static void
Damien Miller630d6f42002-01-22 23:17:30 +1100166input_userauth_request(int type, u_int32_t seq, void *ctxt)
Damien Millereba71ba2000-04-29 23:57:08 +1000167{
Damien Miller874d77b2000-10-14 16:23:11 +1100168 Authctxt *authctxt = ctxt;
169 Authmethod *m = NULL;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000170 char *user, *service, *method, *style = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000171 int authenticated = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000172
Damien Miller874d77b2000-10-14 16:23:11 +1100173 if (authctxt == NULL)
174 fatal("input_userauth_request: no authctxt");
Damien Millereba71ba2000-04-29 23:57:08 +1000175
Damien Miller874d77b2000-10-14 16:23:11 +1100176 user = packet_get_string(NULL);
177 service = packet_get_string(NULL);
178 method = packet_get_string(NULL);
179 debug("userauth-request for user %s service %s method %s", user, service, method);
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000180 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
Damien Miller874d77b2000-10-14 16:23:11 +1100181
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000182 if ((style = strchr(user, ':')) != NULL)
183 *style++ = 0;
184
Kevin Stevesef4eea92001-02-05 12:42:17 +0000185 if (authctxt->attempt++ == 0) {
Damien Miller3a5b0232002-03-13 13:19:42 +1100186 /* setup auth context */
Kevin Steves205cc1e2002-03-22 20:43:05 +0000187 authctxt->pw = PRIVSEP(getpwnamallow(user));
188 if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
Damien Miller874d77b2000-10-14 16:23:11 +1100189 authctxt->valid = 1;
190 debug2("input_userauth_request: setting up authctxt for %s", user);
191#ifdef USE_PAM
Kevin Steves205cc1e2002-03-22 20:43:05 +0000192 start_pam(authctxt->pw->pw_name);
Damien Miller874d77b2000-10-14 16:23:11 +1100193#endif
194 } else {
195 log("input_userauth_request: illegal user %s", user);
Damien Miller22e22bf2001-01-19 15:46:38 +1100196#ifdef USE_PAM
197 start_pam("NOUSER");
198#endif
Damien Miller874d77b2000-10-14 16:23:11 +1100199 }
Ben Lindstrom7ebb6352002-03-22 03:04:08 +0000200 setproctitle("%s%s", authctxt->pw ? user : "unknown",
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000201 use_privsep ? " [net]" : "");
Damien Miller874d77b2000-10-14 16:23:11 +1100202 authctxt->user = xstrdup(user);
203 authctxt->service = xstrdup(service);
Ben Lindstrom9d0c0662001-06-09 01:40:00 +0000204 authctxt->style = style ? xstrdup(style) : NULL;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000205 if (use_privsep)
206 mm_inform_authserv(service, style);
Ben Lindstrom9d0c0662001-06-09 01:40:00 +0000207 } else if (strcmp(user, authctxt->user) != 0 ||
208 strcmp(service, authctxt->service) != 0) {
209 packet_disconnect("Change of username or service not allowed: "
210 "(%s,%s) -> (%s,%s)",
211 authctxt->user, authctxt->service, user, service);
Damien Millereba71ba2000-04-29 23:57:08 +1000212 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000213 /* reset state */
Damien Milleree116252001-12-21 12:42:34 +1100214 auth2_challenge_stop(authctxt);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000215 authctxt->postponed = 0;
Damien Millerb70b61f2000-09-16 16:25:12 +1100216
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000217 /* try to authenticate user */
Damien Miller874d77b2000-10-14 16:23:11 +1100218 m = authmethod_lookup(method);
219 if (m != NULL) {
220 debug2("input_userauth_request: try method %s", method);
221 authenticated = m->userauth(authctxt);
Damien Miller874d77b2000-10-14 16:23:11 +1100222 }
Damien Miller5d57e502001-03-30 10:48:31 +1000223 userauth_finish(authctxt, authenticated, method);
224
225 xfree(service);
226 xfree(user);
227 xfree(method);
228}
229
230void
231userauth_finish(Authctxt *authctxt, int authenticated, char *method)
232{
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000233 char *methods;
234
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000235 if (!authctxt->valid && authenticated)
236 fatal("INTERNAL ERROR: authenticated invalid user %s",
237 authctxt->user);
Damien Millerb70b61f2000-09-16 16:25:12 +1100238
Damien Miller874d77b2000-10-14 16:23:11 +1100239 /* Special handling for root */
Ben Lindstromd8a90212001-02-15 03:08:27 +0000240 if (authenticated && authctxt->pw->pw_uid == 0 &&
241 !auth_root_allowed(method))
Damien Millereba71ba2000-04-29 23:57:08 +1000242 authenticated = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000243
244#ifdef USE_PAM
Damien Millerc83de6d2001-02-16 14:17:59 +1100245 if (authenticated && authctxt->user && !do_pam_account(authctxt->user,
246 NULL))
Damien Millerb70b61f2000-09-16 16:25:12 +1100247 authenticated = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000248#endif /* USE_PAM */
249
Damien Miller874d77b2000-10-14 16:23:11 +1100250 /* Log before sending the reply */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000251 auth_log(authctxt, authenticated, method, " ssh2");
252
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000253 if (authctxt->postponed)
254 return;
255
256 /* XXX todo: check if multiple auth methods are needed */
257 if (authenticated == 1) {
258 /* turn off userauth */
Damien Miller7d053392002-01-22 23:24:13 +1100259 dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000260 packet_start(SSH2_MSG_USERAUTH_SUCCESS);
261 packet_send();
262 packet_write_wait();
263 /* now we can break out */
264 authctxt->success = 1;
265 } else {
Damien Millere49d0962001-11-13 23:46:18 +1100266 if (authctxt->failures++ > AUTH_FAIL_MAX) {
267#ifdef WITH_AIXAUTHENTICATE
268 loginfailed(authctxt->user,
Damien Millerf3451a22002-02-05 12:40:46 +1100269 get_canonical_hostname(options.verify_reverse_mapping),
Damien Millere49d0962001-11-13 23:46:18 +1100270 "ssh");
271#endif /* WITH_AIXAUTHENTICATE */
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000272 packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
Damien Millere49d0962001-11-13 23:46:18 +1100273 }
Ben Lindstromcd4349f2001-06-09 00:23:17 +0000274 methods = authmethods_get();
275 packet_start(SSH2_MSG_USERAUTH_FAILURE);
276 packet_put_cstring(methods);
277 packet_put_char(0); /* XXX partial success, unused */
278 packet_send();
279 packet_write_wait();
280 xfree(methods);
281 }
Damien Miller874d77b2000-10-14 16:23:11 +1100282}
283
Ben Lindstrombba81212001-06-25 05:01:22 +0000284static void
Ben Lindstrom48bd7c12001-01-09 00:35:42 +0000285userauth_banner(void)
286{
287 struct stat st;
288 char *banner = NULL;
289 off_t len, n;
290 int fd;
291
292 if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
293 return;
Ben Lindstrom0cae0402001-04-04 23:47:52 +0000294 if ((fd = open(options.banner, O_RDONLY)) < 0)
Ben Lindstrom48bd7c12001-01-09 00:35:42 +0000295 return;
Ben Lindstrom48bd7c12001-01-09 00:35:42 +0000296 if (fstat(fd, &st) < 0)
297 goto done;
298 len = st.st_size;
299 banner = xmalloc(len + 1);
300 if ((n = read(fd, banner, len)) < 0)
301 goto done;
302 banner[n] = '\0';
303 packet_start(SSH2_MSG_USERAUTH_BANNER);
304 packet_put_cstring(banner);
305 packet_put_cstring(""); /* language, unused */
306 packet_send();
307 debug("userauth_banner: sent");
308done:
309 if (banner)
310 xfree(banner);
311 close(fd);
312 return;
313}
Damien Miller874d77b2000-10-14 16:23:11 +1100314
Ben Lindstrombba81212001-06-25 05:01:22 +0000315static int
Damien Miller874d77b2000-10-14 16:23:11 +1100316userauth_none(Authctxt *authctxt)
Damien Millereba71ba2000-04-29 23:57:08 +1000317{
Damien Miller874d77b2000-10-14 16:23:11 +1100318 /* disable method "none", only allowed one time */
319 Authmethod *m = authmethod_lookup("none");
320 if (m != NULL)
321 m->enabled = NULL;
Damien Miller48b03fc2002-01-22 23:11:40 +1100322 packet_check_eom();
Kevin Stevesef4eea92001-02-05 12:42:17 +0000323 userauth_banner();
Damien Millerb8c656e2000-06-28 15:22:41 +1000324
Damien Miller874d77b2000-10-14 16:23:11 +1100325 if (authctxt->valid == 0)
326 return(0);
Damien Miller3a5b0232002-03-13 13:19:42 +1100327
328#ifdef HAVE_CYGWIN
329 if (check_nt_auth(1, authctxt->pw) == 0)
330 return(0);
Damien Miller874d77b2000-10-14 16:23:11 +1100331#endif
Damien Miller3a5b0232002-03-13 13:19:42 +1100332#ifdef USE_PAM
333 return auth_pam_password(authctxt->pw, "");
334#elif defined(HAVE_OSF_SIA)
335 return 0;
336#else /* !HAVE_OSF_SIA && !USE_PAM */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000337 return PRIVSEP(auth_password(authctxt, ""));
Damien Miller3a5b0232002-03-13 13:19:42 +1100338#endif /* USE_PAM */
Damien Millereba71ba2000-04-29 23:57:08 +1000339}
Damien Miller874d77b2000-10-14 16:23:11 +1100340
Ben Lindstrombba81212001-06-25 05:01:22 +0000341static int
Damien Miller874d77b2000-10-14 16:23:11 +1100342userauth_passwd(Authctxt *authctxt)
Damien Millereba71ba2000-04-29 23:57:08 +1000343{
344 char *password;
345 int authenticated = 0;
346 int change;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000347 u_int len;
Damien Millereba71ba2000-04-29 23:57:08 +1000348 change = packet_get_char();
349 if (change)
350 log("password change not supported");
351 password = packet_get_string(&len);
Damien Miller48b03fc2002-01-22 23:11:40 +1100352 packet_check_eom();
Damien Miller3a5b0232002-03-13 13:19:42 +1100353 if (authctxt->valid &&
354#ifdef HAVE_CYGWIN
355 check_nt_auth(1, authctxt->pw) &&
Damien Miller874d77b2000-10-14 16:23:11 +1100356#endif
Damien Miller3a5b0232002-03-13 13:19:42 +1100357#ifdef USE_PAM
358 auth_pam_password(authctxt->pw, password) == 1)
359#elif defined(HAVE_OSF_SIA)
360 auth_sia_password(authctxt->user, password) == 1)
361#else /* !USE_PAM && !HAVE_OSF_SIA */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000362 PRIVSEP(auth_password(authctxt, password)) == 1)
Damien Miller3a5b0232002-03-13 13:19:42 +1100363#endif /* USE_PAM */
364 authenticated = 1;
Damien Millereba71ba2000-04-29 23:57:08 +1000365 memset(password, 0, len);
366 xfree(password);
367 return authenticated;
368}
Damien Miller874d77b2000-10-14 16:23:11 +1100369
Ben Lindstrombba81212001-06-25 05:01:22 +0000370static int
Damien Miller874d77b2000-10-14 16:23:11 +1100371userauth_kbdint(Authctxt *authctxt)
372{
373 int authenticated = 0;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000374 char *lang, *devs;
Damien Miller874d77b2000-10-14 16:23:11 +1100375
376 lang = packet_get_string(NULL);
377 devs = packet_get_string(NULL);
Damien Miller48b03fc2002-01-22 23:11:40 +1100378 packet_check_eom();
Damien Miller874d77b2000-10-14 16:23:11 +1100379
Ben Lindstrom551ea372001-06-05 18:56:16 +0000380 debug("keyboard-interactive devs %s", devs);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000381
Ben Lindstrom551ea372001-06-05 18:56:16 +0000382 if (options.challenge_response_authentication)
Ben Lindstrom95fb2dd2001-01-23 03:12:10 +0000383 authenticated = auth2_challenge(authctxt, devs);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000384
Damien Millerb8481582000-12-03 11:51:51 +1100385#ifdef USE_PAM
Damien Millerf8154422001-04-25 22:44:14 +1000386 if (authenticated == 0 && options.pam_authentication_via_kbd_int)
Damien Millerb8481582000-12-03 11:51:51 +1100387 authenticated = auth2_pam(authctxt);
388#endif
Damien Miller874d77b2000-10-14 16:23:11 +1100389 xfree(devs);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000390 xfree(lang);
Damien Miller874d77b2000-10-14 16:23:11 +1100391#ifdef HAVE_CYGWIN
Damien Miller0dea79d2001-12-29 14:08:28 +1100392 if (check_nt_auth(0, authctxt->pw) == 0)
Damien Miller874d77b2000-10-14 16:23:11 +1100393 return(0);
394#endif
395 return authenticated;
396}
397
Ben Lindstrombba81212001-06-25 05:01:22 +0000398static int
Damien Miller874d77b2000-10-14 16:23:11 +1100399userauth_pubkey(Authctxt *authctxt)
Damien Millereba71ba2000-04-29 23:57:08 +1000400{
401 Buffer b;
Damien Miller9b74bfc2002-02-05 12:26:03 +1100402 Key *key = NULL;
Ben Lindstrom90fd8142002-02-26 18:09:42 +0000403 char *pkalg;
404 u_char *pkblob, *sig;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000405 u_int alen, blen, slen;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100406 int have_sig, pktype;
Damien Millereba71ba2000-04-29 23:57:08 +1000407 int authenticated = 0;
408
Damien Miller874d77b2000-10-14 16:23:11 +1100409 if (!authctxt->valid) {
410 debug2("userauth_pubkey: disabled because of invalid user");
Damien Millereba71ba2000-04-29 23:57:08 +1000411 return 0;
412 }
413 have_sig = packet_get_char();
Ben Lindstromd121f612000-12-03 17:00:47 +0000414 if (datafellows & SSH_BUG_PKAUTH) {
415 debug2("userauth_pubkey: SSH_BUG_PKAUTH");
416 /* no explicit pkalg given */
417 pkblob = packet_get_string(&blen);
418 buffer_init(&b);
419 buffer_append(&b, pkblob, blen);
420 /* so we have to extract the pkalg from the pkblob */
421 pkalg = buffer_get_string(&b, &alen);
422 buffer_free(&b);
423 } else {
424 pkalg = packet_get_string(&alen);
425 pkblob = packet_get_string(&blen);
426 }
Damien Miller0bc1bd82000-11-13 22:57:25 +1100427 pktype = key_type_from_name(pkalg);
428 if (pktype == KEY_UNSPEC) {
Ben Lindstromd121f612000-12-03 17:00:47 +0000429 /* this is perfectly legal */
Damien Miller9b74bfc2002-02-05 12:26:03 +1100430 log("userauth_pubkey: unsupported public key algorithm: %s",
431 pkalg);
432 goto done;
Damien Millereba71ba2000-04-29 23:57:08 +1000433 }
Damien Miller0bc1bd82000-11-13 22:57:25 +1100434 key = key_from_blob(pkblob, blen);
Damien Miller9b74bfc2002-02-05 12:26:03 +1100435 if (key == NULL) {
436 error("userauth_pubkey: cannot decode key: %s", pkalg);
437 goto done;
Damien Millereba71ba2000-04-29 23:57:08 +1000438 }
Damien Miller9b74bfc2002-02-05 12:26:03 +1100439 if (key->type != pktype) {
440 error("userauth_pubkey: type mismatch for decoded key "
441 "(received %d, expected %d)", key->type, pktype);
442 goto done;
443 }
444 if (have_sig) {
445 sig = packet_get_string(&slen);
446 packet_check_eom();
447 buffer_init(&b);
448 if (datafellows & SSH_OLD_SESSIONID) {
449 buffer_append(&b, session_id2, session_id2_len);
450 } else {
451 buffer_put_string(&b, session_id2, session_id2_len);
452 }
453 /* reconstruct packet */
454 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
455 buffer_put_cstring(&b, authctxt->user);
456 buffer_put_cstring(&b,
457 datafellows & SSH_BUG_PKSERVICE ?
458 "ssh-userauth" :
459 authctxt->service);
460 if (datafellows & SSH_BUG_PKAUTH) {
461 buffer_put_char(&b, have_sig);
462 } else {
463 buffer_put_cstring(&b, "publickey");
464 buffer_put_char(&b, have_sig);
465 buffer_put_cstring(&b, pkalg);
466 }
467 buffer_put_string(&b, pkblob, blen);
468#ifdef DEBUG_PK
469 buffer_dump(&b);
470#endif
471 /* test for correct signature */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000472 authenticated = 0;
473 if (PRIVSEP(user_key_allowed(authctxt->pw, key)) &&
474 PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
475 buffer_len(&b))) == 1)
Damien Miller3a5b0232002-03-13 13:19:42 +1100476 authenticated = 1;
Damien Miller9b74bfc2002-02-05 12:26:03 +1100477 buffer_clear(&b);
478 xfree(sig);
479 } else {
480 debug("test whether pkalg/pkblob are acceptable");
481 packet_check_eom();
482
483 /* XXX fake reply and always send PK_OK ? */
484 /*
485 * XXX this allows testing whether a user is allowed
486 * to login: if you happen to have a valid pubkey this
487 * message is sent. the message is NEVER sent at all
488 * if a user is not allowed to login. is this an
489 * issue? -markus
490 */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000491 if (PRIVSEP(user_key_allowed(authctxt->pw, key))) {
Damien Miller9b74bfc2002-02-05 12:26:03 +1100492 packet_start(SSH2_MSG_USERAUTH_PK_OK);
493 packet_put_string(pkalg, alen);
494 packet_put_string(pkblob, blen);
495 packet_send();
496 packet_write_wait();
497 authctxt->postponed = 1;
498 }
499 }
500 if (authenticated != 1)
501 auth_clear_options();
502done:
Damien Miller0bc1bd82000-11-13 22:57:25 +1100503 debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
Damien Miller9b74bfc2002-02-05 12:26:03 +1100504 if (key != NULL)
505 key_free(key);
Damien Millereba71ba2000-04-29 23:57:08 +1000506 xfree(pkalg);
507 xfree(pkblob);
Damien Miller874d77b2000-10-14 16:23:11 +1100508#ifdef HAVE_CYGWIN
Damien Miller0dea79d2001-12-29 14:08:28 +1100509 if (check_nt_auth(0, authctxt->pw) == 0)
Damien Miller874d77b2000-10-14 16:23:11 +1100510 return(0);
511#endif
Damien Millereba71ba2000-04-29 23:57:08 +1000512 return authenticated;
513}
514
Ben Lindstrombba81212001-06-25 05:01:22 +0000515static int
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000516userauth_hostbased(Authctxt *authctxt)
517{
518 Buffer b;
Damien Miller9b74bfc2002-02-05 12:26:03 +1100519 Key *key = NULL;
Ben Lindstrom90fd8142002-02-26 18:09:42 +0000520 char *pkalg, *cuser, *chost, *service;
521 u_char *pkblob, *sig;
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000522 u_int alen, blen, slen;
523 int pktype;
524 int authenticated = 0;
525
526 if (!authctxt->valid) {
527 debug2("userauth_hostbased: disabled because of invalid user");
528 return 0;
529 }
530 pkalg = packet_get_string(&alen);
531 pkblob = packet_get_string(&blen);
532 chost = packet_get_string(NULL);
533 cuser = packet_get_string(NULL);
534 sig = packet_get_string(&slen);
535
536 debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
537 cuser, chost, pkalg, slen);
538#ifdef DEBUG_PK
539 debug("signature:");
540 buffer_init(&b);
541 buffer_append(&b, sig, slen);
542 buffer_dump(&b);
543 buffer_free(&b);
544#endif
545 pktype = key_type_from_name(pkalg);
546 if (pktype == KEY_UNSPEC) {
547 /* this is perfectly legal */
548 log("userauth_hostbased: unsupported "
549 "public key algorithm: %s", pkalg);
550 goto done;
551 }
552 key = key_from_blob(pkblob, blen);
553 if (key == NULL) {
Damien Miller9b74bfc2002-02-05 12:26:03 +1100554 error("userauth_hostbased: cannot decode key: %s", pkalg);
555 goto done;
556 }
557 if (key->type != pktype) {
558 error("userauth_hostbased: type mismatch for decoded key "
559 "(received %d, expected %d)", key->type, pktype);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000560 goto done;
561 }
Ben Lindstrom671388f2001-04-19 20:40:45 +0000562 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
563 authctxt->service;
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000564 buffer_init(&b);
Ben Lindstrom671388f2001-04-19 20:40:45 +0000565 buffer_put_string(&b, session_id2, session_id2_len);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000566 /* reconstruct packet */
567 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
568 buffer_put_cstring(&b, authctxt->user);
Ben Lindstrom671388f2001-04-19 20:40:45 +0000569 buffer_put_cstring(&b, service);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000570 buffer_put_cstring(&b, "hostbased");
571 buffer_put_string(&b, pkalg, alen);
572 buffer_put_string(&b, pkblob, blen);
573 buffer_put_cstring(&b, chost);
574 buffer_put_cstring(&b, cuser);
575#ifdef DEBUG_PK
576 buffer_dump(&b);
577#endif
578 /* test for allowed key and correct signature */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000579 authenticated = 0;
580 if (PRIVSEP(hostbased_key_allowed(authctxt->pw, cuser, chost, key)) &&
581 PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
582 buffer_len(&b))) == 1)
Damien Miller3a5b0232002-03-13 13:19:42 +1100583 authenticated = 1;
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000584
585 buffer_clear(&b);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000586done:
587 debug2("userauth_hostbased: authenticated %d", authenticated);
Damien Miller9b74bfc2002-02-05 12:26:03 +1100588 if (key != NULL)
589 key_free(key);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000590 xfree(pkalg);
591 xfree(pkblob);
592 xfree(cuser);
593 xfree(chost);
594 xfree(sig);
595 return authenticated;
596}
597
Damien Miller874d77b2000-10-14 16:23:11 +1100598/* get current user */
Damien Millereba71ba2000-04-29 23:57:08 +1000599
600struct passwd*
601auth_get_user(void)
602{
Damien Miller874d77b2000-10-14 16:23:11 +1100603 return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000604}
605
Damien Miller874d77b2000-10-14 16:23:11 +1100606#define DELIM ","
Damien Millereba71ba2000-04-29 23:57:08 +1000607
Ben Lindstrom79073822001-07-04 03:42:30 +0000608static char *
Damien Miller874d77b2000-10-14 16:23:11 +1100609authmethods_get(void)
610{
611 Authmethod *method = NULL;
Damien Miller0e3b8722002-01-22 23:26:38 +1100612 Buffer b;
Damien Miller874d77b2000-10-14 16:23:11 +1100613 char *list;
614
Damien Miller0e3b8722002-01-22 23:26:38 +1100615 buffer_init(&b);
Damien Miller874d77b2000-10-14 16:23:11 +1100616 for (method = authmethods; method->name != NULL; method++) {
617 if (strcmp(method->name, "none") == 0)
618 continue;
619 if (method->enabled != NULL && *(method->enabled) != 0) {
Damien Miller0e3b8722002-01-22 23:26:38 +1100620 if (buffer_len(&b) > 0)
621 buffer_append(&b, ",", 1);
622 buffer_append(&b, method->name, strlen(method->name));
Damien Millereba71ba2000-04-29 23:57:08 +1000623 }
624 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100625 buffer_append(&b, "\0", 1);
626 list = xstrdup(buffer_ptr(&b));
627 buffer_free(&b);
Damien Miller874d77b2000-10-14 16:23:11 +1100628 return list;
629}
630
Ben Lindstrombba81212001-06-25 05:01:22 +0000631static Authmethod *
Damien Miller874d77b2000-10-14 16:23:11 +1100632authmethod_lookup(const char *name)
633{
634 Authmethod *method = NULL;
635 if (name != NULL)
636 for (method = authmethods; method->name != NULL; method++)
637 if (method->enabled != NULL &&
638 *(method->enabled) != 0 &&
639 strcmp(name, method->name) == 0)
640 return method;
641 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
642 return NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000643}
644
645/* return 1 if user allows given key */
Ben Lindstrombba81212001-06-25 05:01:22 +0000646static int
Ben Lindstromf96704d2001-06-25 04:17:12 +0000647user_key_allowed2(struct passwd *pw, Key *key, char *file)
Damien Millereba71ba2000-04-29 23:57:08 +1000648{
Ben Lindstromf96704d2001-06-25 04:17:12 +0000649 char line[8192];
Damien Millereba71ba2000-04-29 23:57:08 +1000650 int found_key = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000651 FILE *f;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000652 u_long linenum = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000653 struct stat st;
654 Key *found;
Damien Millerda9edca2001-12-21 12:48:54 +1100655 char *fp;
Damien Millereba71ba2000-04-29 23:57:08 +1000656
Damien Miller874d77b2000-10-14 16:23:11 +1100657 if (pw == NULL)
658 return 0;
659
Damien Millereba71ba2000-04-29 23:57:08 +1000660 /* Temporarily use the user's uid. */
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000661 temporarily_use_uid(pw);
Damien Millereba71ba2000-04-29 23:57:08 +1000662
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000663 debug("trying public key file %s", file);
Damien Millereba71ba2000-04-29 23:57:08 +1000664
665 /* Fail quietly if file does not exist */
666 if (stat(file, &st) < 0) {
667 /* Restore the privileged uid. */
668 restore_uid();
669 return 0;
670 }
671 /* Open the file containing the authorized keys. */
672 f = fopen(file, "r");
673 if (!f) {
674 /* Restore the privileged uid. */
675 restore_uid();
676 return 0;
677 }
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000678 if (options.strict_modes &&
Ben Lindstrom90279d82001-07-04 03:56:56 +0000679 secure_filename(f, file, pw, line, sizeof(line)) != 0) {
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000680 fclose(f);
681 log("Authentication refused: %s", line);
682 restore_uid();
683 return 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000684 }
Ben Lindstrombfb3a0e2001-06-05 20:25:05 +0000685
Damien Millereba71ba2000-04-29 23:57:08 +1000686 found_key = 0;
Damien Millerd3444942000-09-30 14:20:03 +1100687 found = key_new(key->type);
Damien Millereba71ba2000-04-29 23:57:08 +1000688
689 while (fgets(line, sizeof(line), f)) {
Damien Millerf6d9e222000-06-18 14:50:44 +1000690 char *cp, *options = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000691 linenum++;
692 /* Skip leading whitespace, empty and comment lines. */
693 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
694 ;
695 if (!*cp || *cp == '\n' || *cp == '#')
696 continue;
Damien Millerf6d9e222000-06-18 14:50:44 +1000697
Ben Lindstrom1bc3bdb2001-09-20 23:11:26 +0000698 if (key_read(found, &cp) != 1) {
Damien Millerf6d9e222000-06-18 14:50:44 +1000699 /* no key? check if there are options for this key */
700 int quoted = 0;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100701 debug2("user_key_allowed: check options: '%s'", cp);
Damien Millerf6d9e222000-06-18 14:50:44 +1000702 options = cp;
703 for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
704 if (*cp == '\\' && cp[1] == '"')
705 cp++; /* Skip both */
706 else if (*cp == '"')
707 quoted = !quoted;
708 }
709 /* Skip remaining whitespace. */
710 for (; *cp == ' ' || *cp == '\t'; cp++)
711 ;
Ben Lindstrom1bc3bdb2001-09-20 23:11:26 +0000712 if (key_read(found, &cp) != 1) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100713 debug2("user_key_allowed: advance: '%s'", cp);
Damien Millerf6d9e222000-06-18 14:50:44 +1000714 /* still no key? advance to next line*/
715 continue;
716 }
717 }
718 if (key_equal(found, key) &&
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000719 auth_parse_options(pw, options, file, linenum) == 1) {
Damien Millereba71ba2000-04-29 23:57:08 +1000720 found_key = 1;
Ben Lindstrom940fb862001-08-06 21:01:49 +0000721 debug("matching key found: file %s, line %lu",
Damien Millereba71ba2000-04-29 23:57:08 +1000722 file, linenum);
Damien Millerda9edca2001-12-21 12:48:54 +1100723 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
724 verbose("Found matching %s key: %s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100725 key_type(found), fp);
Damien Millerda9edca2001-12-21 12:48:54 +1100726 xfree(fp);
Damien Millereba71ba2000-04-29 23:57:08 +1000727 break;
728 }
729 }
730 restore_uid();
731 fclose(f);
732 key_free(found);
Ben Lindstromb54873a2001-03-11 20:01:55 +0000733 if (!found_key)
734 debug2("key not found");
Damien Millereba71ba2000-04-29 23:57:08 +1000735 return found_key;
736}
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000737
Ben Lindstromf96704d2001-06-25 04:17:12 +0000738/* check whether given key is in .ssh/authorized_keys* */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000739int
Ben Lindstromf96704d2001-06-25 04:17:12 +0000740user_key_allowed(struct passwd *pw, Key *key)
741{
742 int success;
743 char *file;
744
745 file = authorized_keys_file(pw);
746 success = user_key_allowed2(pw, key, file);
747 xfree(file);
748 if (success)
749 return success;
750
751 /* try suffix "2" for backward compat, too */
752 file = authorized_keys_file2(pw);
753 success = user_key_allowed2(pw, key, file);
754 xfree(file);
755 return success;
756}
757
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000758/* return 1 if given hostkey is allowed */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000759int
Ben Lindstrom4aa603c2001-04-19 20:38:06 +0000760hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000761 Key *key)
762{
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000763 const char *resolvedname, *ipaddr, *lookup;
Ben Lindstrom65366a82001-12-06 16:32:47 +0000764 HostStatus host_status;
765 int len;
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000766
Damien Millerc5d86352002-02-05 12:13:41 +1100767 resolvedname = get_canonical_hostname(options.verify_reverse_mapping);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000768 ipaddr = get_remote_ipaddr();
769
Ben Lindstrom2bffd6f2001-04-19 20:35:40 +0000770 debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
771 chost, resolvedname, ipaddr);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000772
773 if (options.hostbased_uses_name_from_packet_only) {
774 if (auth_rhosts2(pw, cuser, chost, chost) == 0)
775 return 0;
776 lookup = chost;
777 } else {
Ben Lindstrom2bffd6f2001-04-19 20:35:40 +0000778 if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
779 debug2("stripping trailing dot from chost %s", chost);
780 chost[len - 1] = '\0';
781 }
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000782 if (strcasecmp(resolvedname, chost) != 0)
783 log("userauth_hostbased mismatch: "
784 "client sends %s, but we resolve %s to %s",
785 chost, ipaddr, resolvedname);
786 if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
787 return 0;
788 lookup = resolvedname;
789 }
790 debug2("userauth_hostbased: access allowed by auth_rhosts2");
791
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000792 host_status = check_key_in_hostfiles(pw, key, lookup,
793 _PATH_SSH_SYSTEM_HOSTFILE,
Ben Lindstroma4789ef2001-06-25 04:40:49 +0000794 options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000795
Ben Lindstrom83647ce2001-06-25 04:30:16 +0000796 /* backward compat if no key has been found. */
797 if (host_status == HOST_NEW)
798 host_status = check_key_in_hostfiles(pw, key, lookup,
799 _PATH_SSH_SYSTEM_HOSTFILE2,
Ben Lindstroma4789ef2001-06-25 04:40:49 +0000800 options.ignore_user_known_hosts ? NULL :
801 _PATH_SSH_USER_HOSTFILE2);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000802
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000803 return (host_status == HOST_OK);
804}