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3c0ef626 1/*
2 * Kerberos v5 authentication and ticket-passing routines.
350391c5 3 *
3c0ef626 4 * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $
3c0ef626 5 */
350391c5 6/*
7 * Copyright (c) 2002 Daniel Kouril. All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
3c0ef626 29
30#include "includes.h"
bfe49944 31RCSID("$OpenBSD: auth-krb5.c,v 1.10 2002/11/21 23:03:51 deraadt Exp $");
e9702f7d 32
3c0ef626 33#include "ssh.h"
34#include "ssh1.h"
35#include "packet.h"
36#include "xmalloc.h"
37#include "log.h"
38#include "servconf.h"
39#include "uidswap.h"
40#include "auth.h"
41
42#ifdef KRB5
43#include <krb5.h>
63119dd9 44#ifndef HEIMDAL
45#define krb5_get_err_text(context,code) error_message(code)
46#endif /* !HEIMDAL */
3c0ef626 47
48extern ServerOptions options;
49
50static int
51krb5_init(void *context)
52{
53 Authctxt *authctxt = (Authctxt *)context;
54 krb5_error_code problem;
55 static int cleanup_registered = 0;
e9702f7d 56
3c0ef626 57 if (authctxt->krb5_ctx == NULL) {
58 problem = krb5_init_context(&authctxt->krb5_ctx);
59 if (problem)
60 return (problem);
61 krb5_init_ets(authctxt->krb5_ctx);
62 }
63 if (!cleanup_registered) {
64 fatal_add_cleanup(krb5_cleanup_proc, authctxt);
65 cleanup_registered = 1;
66 }
67 return (0);
68}
69
70/*
71 * Try krb5 authentication. server_user is passed for logging purposes
72 * only, in auth is received ticket, in client is returned principal
73 * from the ticket
74 */
e9702f7d 75int
d03f4262 76auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *reply)
3c0ef626 77{
78 krb5_error_code problem;
79 krb5_principal server;
3c0ef626 80 krb5_ticket *ticket;
81 int fd, ret;
82
83 ret = 0;
84 server = NULL;
85 ticket = NULL;
d03f4262 86 reply->length = 0;
e9702f7d 87
3c0ef626 88 problem = krb5_init(authctxt);
e9702f7d 89 if (problem)
3c0ef626 90 goto err;
e9702f7d 91
3c0ef626 92 problem = krb5_auth_con_init(authctxt->krb5_ctx,
93 &authctxt->krb5_auth_ctx);
94 if (problem)
95 goto err;
e9702f7d 96
3c0ef626 97 fd = packet_get_connection_in();
63119dd9 98#ifdef HEIMDAL
3c0ef626 99 problem = krb5_auth_con_setaddrs_from_fd(authctxt->krb5_ctx,
100 authctxt->krb5_auth_ctx, &fd);
63119dd9 101#else
102 problem = krb5_auth_con_genaddrs(authctxt->krb5_ctx,
103 authctxt->krb5_auth_ctx,fd,
104 KRB5_AUTH_CONTEXT_GENERATE_REMOTE_FULL_ADDR |
105 KRB5_AUTH_CONTEXT_GENERATE_LOCAL_FULL_ADDR);
106#endif
3c0ef626 107 if (problem)
108 goto err;
e9702f7d 109
bfe49944 110 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
3c0ef626 111 KRB5_NT_SRV_HST, &server);
112 if (problem)
113 goto err;
e9702f7d 114
3c0ef626 115 problem = krb5_rd_req(authctxt->krb5_ctx, &authctxt->krb5_auth_ctx,
116 auth, server, NULL, NULL, &ticket);
117 if (problem)
118 goto err;
905081a4 119
120#ifdef HEIMDAL
3c0ef626 121 problem = krb5_copy_principal(authctxt->krb5_ctx, ticket->client,
122 &authctxt->krb5_user);
63119dd9 123#else
905081a4 124 problem = krb5_copy_principal(authctxt->krb5_ctx,
125 ticket->enc_part2->client,
126 &authctxt->krb5_user);
63119dd9 127#endif
3c0ef626 128 if (problem)
129 goto err;
e9702f7d 130
3c0ef626 131 /* if client wants mutual auth */
132 problem = krb5_mk_rep(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
d03f4262 133 reply);
3c0ef626 134 if (problem)
135 goto err;
e9702f7d 136
3c0ef626 137 /* Check .k5login authorization now. */
138 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
139 authctxt->pw->pw_name))
140 goto err;
e9702f7d 141
3c0ef626 142 if (client)
143 krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user,
144 client);
e9702f7d 145
3c0ef626 146 ret = 1;
147 err:
148 if (server)
149 krb5_free_principal(authctxt->krb5_ctx, server);
150 if (ticket)
151 krb5_free_ticket(authctxt->krb5_ctx, ticket);
d03f4262 152 if (!ret && reply->length) {
153 xfree(reply->data);
154 memset(reply, 0, sizeof(*reply));
155 }
e9702f7d 156
157 if (problem) {
158 if (authctxt->krb5_ctx != NULL)
159 debug("Kerberos v5 authentication failed: %s",
160 krb5_get_err_text(authctxt->krb5_ctx, problem));
161 else
162 debug("Kerberos v5 authentication failed: %d",
163 problem);
164 }
3c0ef626 165
166 return (ret);
167}
168
169int
170auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt)
171{
172 krb5_error_code problem;
173 krb5_ccache ccache = NULL;
174 char *pname;
63119dd9 175 krb5_creds **creds;
905081a4 176
3c0ef626 177 if (authctxt->pw == NULL || authctxt->krb5_user == NULL)
178 return (0);
e9702f7d 179
3c0ef626 180 temporarily_use_uid(authctxt->pw);
905081a4 181
182#ifdef HEIMDAL
3c0ef626 183 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, &ccache);
63119dd9 184#else
185{
905081a4 186 char ccname[40];
187 int tmpfd;
63119dd9 188
905081a4 189 snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid());
190
e444f4cb 191 if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) {
905081a4 192 log("mkstemp(): %.100s", strerror(errno));
193 problem = errno;
194 goto fail;
195 }
196 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
197 log("fchmod(): %.100s", strerror(errno));
198 close(tmpfd);
199 problem = errno;
200 goto fail;
201 }
202 close(tmpfd);
63119dd9 203 problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &ccache);
204}
205#endif
3c0ef626 206 if (problem)
207 goto fail;
e9702f7d 208
3c0ef626 209 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
210 authctxt->krb5_user);
211 if (problem)
212 goto fail;
905081a4 213
214#ifdef HEIMDAL
3c0ef626 215 problem = krb5_rd_cred2(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
216 ccache, tgt);
217 if (problem)
218 goto fail;
63119dd9 219#else
220 problem = krb5_rd_cred(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
221 tgt, &creds, NULL);
905081a4 222 if (problem)
63119dd9 223 goto fail;
224 problem = krb5_cc_store_cred(authctxt->krb5_ctx, ccache, *creds);
225 if (problem)
905081a4 226 goto fail;
63119dd9 227#endif
905081a4 228
3c0ef626 229 authctxt->krb5_fwd_ccache = ccache;
230 ccache = NULL;
e9702f7d 231
3c0ef626 232 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
e9702f7d 233
3c0ef626 234 problem = krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user,
235 &pname);
236 if (problem)
237 goto fail;
e9702f7d 238
3c0ef626 239 debug("Kerberos v5 TGT accepted (%s)", pname);
e9702f7d 240
3c0ef626 241 restore_uid();
e9702f7d 242
3c0ef626 243 return (1);
e9702f7d 244
3c0ef626 245 fail:
246 if (problem)
247 debug("Kerberos v5 TGT passing failed: %s",
248 krb5_get_err_text(authctxt->krb5_ctx, problem));
249 if (ccache)
250 krb5_cc_destroy(authctxt->krb5_ctx, ccache);
e9702f7d 251
3c0ef626 252 restore_uid();
e9702f7d 253
3c0ef626 254 return (0);
255}
256
257int
258auth_krb5_password(Authctxt *authctxt, const char *password)
259{
63119dd9 260#ifndef HEIMDAL
e444f4cb 261 krb5_creds creds;
63119dd9 262 krb5_principal server;
e444f4cb 263 char ccname[40];
264 int tmpfd;
63119dd9 265#endif
3c0ef626 266 krb5_error_code problem;
e9702f7d 267
3c0ef626 268 if (authctxt->pw == NULL)
269 return (0);
e9702f7d 270
3c0ef626 271 temporarily_use_uid(authctxt->pw);
e9702f7d 272
3c0ef626 273 problem = krb5_init(authctxt);
274 if (problem)
275 goto out;
e9702f7d 276
3c0ef626 277 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
278 &authctxt->krb5_user);
279 if (problem)
280 goto out;
905081a4 281
282#ifdef HEIMDAL
3c0ef626 283 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops,
284 &authctxt->krb5_fwd_ccache);
285 if (problem)
286 goto out;
e9702f7d 287
3c0ef626 288 problem = krb5_cc_initialize(authctxt->krb5_ctx,
289 authctxt->krb5_fwd_ccache, authctxt->krb5_user);
290 if (problem)
291 goto out;
905081a4 292
e9702f7d 293 restore_uid();
3c0ef626 294 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
295 authctxt->krb5_fwd_ccache, password, 1, NULL);
e444f4cb 296 temporarily_use_uid(authctxt->pw);
297
298 if (problem)
3c0ef626 299 goto out;
e444f4cb 300
63119dd9 301#else
905081a4 302 problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
e444f4cb 303 authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
304 if (problem)
905081a4 305 goto out;
e444f4cb 306
905081a4 307 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
308 KRB5_NT_SRV_HST, &server);
e444f4cb 309 if (problem)
905081a4 310 goto out;
e444f4cb 311
312 restore_uid();
905081a4 313 problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
314 NULL, NULL, NULL);
905081a4 315 krb5_free_principal(authctxt->krb5_ctx, server);
63119dd9 316 temporarily_use_uid(authctxt->pw);
e444f4cb 317 if (problem)
318 goto out;
319
320 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
321 authctxt->pw->pw_name)) {
44a053a3 322 problem = -1;
e444f4cb 323 goto out;
324 }
325
326 snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid());
327
328 if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) {
329 log("mkstemp(): %.100s", strerror(errno));
330 problem = errno;
905081a4 331 goto out;
332 }
63119dd9 333
e444f4cb 334 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
335 log("fchmod(): %.100s", strerror(errno));
336 close(tmpfd);
337 problem = errno;
905081a4 338 goto out;
339 }
e444f4cb 340 close(tmpfd);
341
342 problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &authctxt->krb5_fwd_ccache);
343 if (problem)
344 goto out;
63119dd9 345
e444f4cb 346 problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
347 authctxt->krb5_user);
905081a4 348 if (problem)
349 goto out;
e444f4cb 350
351 problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
352 &creds);
353 if (problem)
354 goto out;
355#endif
63119dd9 356
3c0ef626 357 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
e9702f7d 358
3c0ef626 359 out:
360 restore_uid();
e9702f7d 361
3c0ef626 362 if (problem) {
e444f4cb 363 if (authctxt->krb5_ctx != NULL && problem!=-1)
e9702f7d 364 debug("Kerberos password authentication failed: %s",
365 krb5_get_err_text(authctxt->krb5_ctx, problem));
366 else
367 debug("Kerberos password authentication failed: %d",
368 problem);
369
3c0ef626 370 krb5_cleanup_proc(authctxt);
e9702f7d 371
3c0ef626 372 if (options.kerberos_or_local_passwd)
373 return (-1);
374 else
375 return (0);
376 }
377 return (1);
378}
379
380void
381krb5_cleanup_proc(void *context)
382{
383 Authctxt *authctxt = (Authctxt *)context;
e9702f7d 384
3c0ef626 385 debug("krb5_cleanup_proc called");
386 if (authctxt->krb5_fwd_ccache) {
387 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
388 authctxt->krb5_fwd_ccache = NULL;
389 }
390 if (authctxt->krb5_user) {
391 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
392 authctxt->krb5_user = NULL;
393 }
394 if (authctxt->krb5_auth_ctx) {
395 krb5_auth_con_free(authctxt->krb5_ctx,
396 authctxt->krb5_auth_ctx);
397 authctxt->krb5_auth_ctx = NULL;
398 }
399 if (authctxt->krb5_ctx) {
400 krb5_free_context(authctxt->krb5_ctx);
401 authctxt->krb5_ctx = NULL;
402 }
403}
404
405#endif /* KRB5 */
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