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aa9f6a6e 1/*
2 * Kerberos v5 authentication and ticket-passing routines.
762715ce 3 *
aa9f6a6e 4 * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $
aa9f6a6e 5 */
bb15f28b 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 */
aa9f6a6e 29
30#include "includes.h"
b77a87e5 31RCSID("$OpenBSD: auth-krb5.c,v 1.10 2002/11/21 23:03:51 deraadt Exp $");
93c3b6de 32
aa9f6a6e 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
751092f9 43
aa9f6a6e 44#include <krb5.h>
12928e80 45#ifndef HEIMDAL
46#define krb5_get_err_text(context,code) error_message(code)
47#endif /* !HEIMDAL */
aa9f6a6e 48
49extern ServerOptions options;
50
51static int
52krb5_init(void *context)
53{
54 Authctxt *authctxt = (Authctxt *)context;
55 krb5_error_code problem;
56 static int cleanup_registered = 0;
a0105740 57
aa9f6a6e 58 if (authctxt->krb5_ctx == NULL) {
59 problem = krb5_init_context(&authctxt->krb5_ctx);
60 if (problem)
61 return (problem);
62 krb5_init_ets(authctxt->krb5_ctx);
63 }
64 if (!cleanup_registered) {
65 fatal_add_cleanup(krb5_cleanup_proc, authctxt);
66 cleanup_registered = 1;
67 }
68 return (0);
69}
70
71/*
72 * Try krb5 authentication. server_user is passed for logging purposes
73 * only, in auth is received ticket, in client is returned principal
74 * from the ticket
75 */
a0105740 76int
696f6bef 77auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *reply)
aa9f6a6e 78{
79 krb5_error_code problem;
80 krb5_principal server;
aa9f6a6e 81 krb5_ticket *ticket;
ede8cea6 82 int fd, ret;
83
84 ret = 0;
aa9f6a6e 85 server = NULL;
86 ticket = NULL;
696f6bef 87 reply->length = 0;
a0105740 88
aa9f6a6e 89 problem = krb5_init(authctxt);
a0105740 90 if (problem)
aa9f6a6e 91 goto err;
a0105740 92
aa9f6a6e 93 problem = krb5_auth_con_init(authctxt->krb5_ctx,
94 &authctxt->krb5_auth_ctx);
95 if (problem)
96 goto err;
a0105740 97
aa9f6a6e 98 fd = packet_get_connection_in();
12928e80 99#ifdef HEIMDAL
aa9f6a6e 100 problem = krb5_auth_con_setaddrs_from_fd(authctxt->krb5_ctx,
101 authctxt->krb5_auth_ctx, &fd);
12928e80 102#else
103 problem = krb5_auth_con_genaddrs(authctxt->krb5_ctx,
104 authctxt->krb5_auth_ctx,fd,
105 KRB5_AUTH_CONTEXT_GENERATE_REMOTE_FULL_ADDR |
106 KRB5_AUTH_CONTEXT_GENERATE_LOCAL_FULL_ADDR);
107#endif
aa9f6a6e 108 if (problem)
109 goto err;
a0105740 110
b77a87e5 111 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
aa9f6a6e 112 KRB5_NT_SRV_HST, &server);
113 if (problem)
114 goto err;
a0105740 115
aa9f6a6e 116 problem = krb5_rd_req(authctxt->krb5_ctx, &authctxt->krb5_auth_ctx,
117 auth, server, NULL, NULL, &ticket);
118 if (problem)
119 goto err;
a0105740 120
12928e80 121#ifdef HEIMDAL
aa9f6a6e 122 problem = krb5_copy_principal(authctxt->krb5_ctx, ticket->client,
123 &authctxt->krb5_user);
12928e80 124#else
125 problem = krb5_copy_principal(authctxt->krb5_ctx,
126 ticket->enc_part2->client,
127 &authctxt->krb5_user);
128#endif
aa9f6a6e 129 if (problem)
130 goto err;
a0105740 131
aa9f6a6e 132 /* if client wants mutual auth */
133 problem = krb5_mk_rep(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
696f6bef 134 reply);
aa9f6a6e 135 if (problem)
136 goto err;
a0105740 137
aa9f6a6e 138 /* Check .k5login authorization now. */
139 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
140 authctxt->pw->pw_name))
141 goto err;
a0105740 142
aa9f6a6e 143 if (client)
144 krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user,
145 client);
a0105740 146
ede8cea6 147 ret = 1;
aa9f6a6e 148 err:
149 if (server)
150 krb5_free_principal(authctxt->krb5_ctx, server);
151 if (ticket)
152 krb5_free_ticket(authctxt->krb5_ctx, ticket);
696f6bef 153 if (!ret && reply->length) {
154 xfree(reply->data);
155 memset(reply, 0, sizeof(*reply));
156 }
a0105740 157
c12337d9 158 if (problem) {
159 if (authctxt->krb5_ctx != NULL)
160 debug("Kerberos v5 authentication failed: %s",
161 krb5_get_err_text(authctxt->krb5_ctx, problem));
162 else
163 debug("Kerberos v5 authentication failed: %d",
164 problem);
165 }
ede8cea6 166
167 return (ret);
aa9f6a6e 168}
169
170int
171auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt)
172{
173 krb5_error_code problem;
174 krb5_ccache ccache = NULL;
175 char *pname;
12928e80 176 krb5_creds **creds;
a0105740 177
aa9f6a6e 178 if (authctxt->pw == NULL || authctxt->krb5_user == NULL)
179 return (0);
a0105740 180
aa9f6a6e 181 temporarily_use_uid(authctxt->pw);
a0105740 182
12928e80 183#ifdef HEIMDAL
aa9f6a6e 184 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, &ccache);
12928e80 185#else
186{
187 char ccname[40];
188 int tmpfd;
189
190 snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid());
191
192 if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) {
bbe88b6d 193 logit("mkstemp(): %.100s", strerror(errno));
12928e80 194 problem = errno;
195 goto fail;
196 }
197 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
bbe88b6d 198 logit("fchmod(): %.100s", strerror(errno));
12928e80 199 close(tmpfd);
200 problem = errno;
201 goto fail;
202 }
203 close(tmpfd);
204 problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &ccache);
205}
206#endif
aa9f6a6e 207 if (problem)
208 goto fail;
a0105740 209
aa9f6a6e 210 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
211 authctxt->krb5_user);
212 if (problem)
213 goto fail;
a0105740 214
12928e80 215#ifdef HEIMDAL
aa9f6a6e 216 problem = krb5_rd_cred2(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
217 ccache, tgt);
218 if (problem)
219 goto fail;
12928e80 220#else
221 problem = krb5_rd_cred(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
222 tgt, &creds, NULL);
223 if (problem)
224 goto fail;
225 problem = krb5_cc_store_cred(authctxt->krb5_ctx, ccache, *creds);
226 if (problem)
227 goto fail;
228#endif
a0105740 229
aa9f6a6e 230 authctxt->krb5_fwd_ccache = ccache;
231 ccache = NULL;
a0105740 232
aa9f6a6e 233 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
a0105740 234
aa9f6a6e 235 problem = krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user,
236 &pname);
237 if (problem)
238 goto fail;
a0105740 239
aa9f6a6e 240 debug("Kerberos v5 TGT accepted (%s)", pname);
a0105740 241
aa9f6a6e 242 restore_uid();
a0105740 243
aa9f6a6e 244 return (1);
a0105740 245
aa9f6a6e 246 fail:
247 if (problem)
248 debug("Kerberos v5 TGT passing failed: %s",
249 krb5_get_err_text(authctxt->krb5_ctx, problem));
250 if (ccache)
251 krb5_cc_destroy(authctxt->krb5_ctx, ccache);
a0105740 252
aa9f6a6e 253 restore_uid();
a0105740 254
aa9f6a6e 255 return (0);
256}
257
258int
259auth_krb5_password(Authctxt *authctxt, const char *password)
260{
12928e80 261#ifndef HEIMDAL
262 krb5_creds creds;
263 krb5_principal server;
264 char ccname[40];
265 int tmpfd;
266#endif
aa9f6a6e 267 krb5_error_code problem;
a0105740 268
aa9f6a6e 269 if (authctxt->pw == NULL)
270 return (0);
a0105740 271
aa9f6a6e 272 temporarily_use_uid(authctxt->pw);
a0105740 273
aa9f6a6e 274 problem = krb5_init(authctxt);
275 if (problem)
276 goto out;
a0105740 277
aa9f6a6e 278 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
279 &authctxt->krb5_user);
280 if (problem)
281 goto out;
a0105740 282
12928e80 283#ifdef HEIMDAL
aa9f6a6e 284 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops,
285 &authctxt->krb5_fwd_ccache);
286 if (problem)
287 goto out;
a0105740 288
aa9f6a6e 289 problem = krb5_cc_initialize(authctxt->krb5_ctx,
290 authctxt->krb5_fwd_ccache, authctxt->krb5_user);
291 if (problem)
292 goto out;
a0105740 293
294 restore_uid();
aa9f6a6e 295 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
296 authctxt->krb5_fwd_ccache, password, 1, NULL);
a0105740 297 temporarily_use_uid(authctxt->pw);
298
aa9f6a6e 299 if (problem)
300 goto out;
a0105740 301
12928e80 302#else
303 problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
304 authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
305 if (problem)
306 goto out;
307
308 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
309 KRB5_NT_SRV_HST, &server);
310 if (problem)
311 goto out;
312
313 restore_uid();
314 problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
315 NULL, NULL, NULL);
316 krb5_free_principal(authctxt->krb5_ctx, server);
317 temporarily_use_uid(authctxt->pw);
318 if (problem)
319 goto out;
320
321 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
322 authctxt->pw->pw_name)) {
875ec275 323 problem = -1;
12928e80 324 goto out;
325 }
326
327 snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid());
328
329 if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) {
bbe88b6d 330 logit("mkstemp(): %.100s", strerror(errno));
12928e80 331 problem = errno;
332 goto out;
333 }
334
335 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
bbe88b6d 336 logit("fchmod(): %.100s", strerror(errno));
12928e80 337 close(tmpfd);
338 problem = errno;
339 goto out;
340 }
341 close(tmpfd);
342
343 problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &authctxt->krb5_fwd_ccache);
344 if (problem)
345 goto out;
346
347 problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
348 authctxt->krb5_user);
349 if (problem)
350 goto out;
351
352 problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
353 &creds);
354 if (problem)
355 goto out;
356#endif
357
aa9f6a6e 358 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
a0105740 359
aa9f6a6e 360 out:
361 restore_uid();
a0105740 362
aa9f6a6e 363 if (problem) {
12928e80 364 if (authctxt->krb5_ctx != NULL && problem!=-1)
c12337d9 365 debug("Kerberos password authentication failed: %s",
366 krb5_get_err_text(authctxt->krb5_ctx, problem));
367 else
368 debug("Kerberos password authentication failed: %d",
369 problem);
a0105740 370
aa9f6a6e 371 krb5_cleanup_proc(authctxt);
a0105740 372
aa9f6a6e 373 if (options.kerberos_or_local_passwd)
374 return (-1);
375 else
376 return (0);
377 }
378 return (1);
379}
380
381void
382krb5_cleanup_proc(void *context)
383{
384 Authctxt *authctxt = (Authctxt *)context;
a0105740 385
aa9f6a6e 386 debug("krb5_cleanup_proc called");
387 if (authctxt->krb5_fwd_ccache) {
388 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
389 authctxt->krb5_fwd_ccache = NULL;
390 }
391 if (authctxt->krb5_user) {
392 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
393 authctxt->krb5_user = NULL;
394 }
395 if (authctxt->krb5_auth_ctx) {
396 krb5_auth_con_free(authctxt->krb5_ctx,
397 authctxt->krb5_auth_ctx);
398 authctxt->krb5_auth_ctx = NULL;
399 }
400 if (authctxt->krb5_ctx) {
401 krb5_free_context(authctxt->krb5_ctx);
402 authctxt->krb5_ctx = NULL;
403 }
404}
405
406#endif /* KRB5 */
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