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1 | /* | |
2 | * Kerberos v5 authentication and ticket-passing routines. | |
3 | * | |
4 | * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $ | |
5 | */ | |
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 | */ | |
29 | ||
30 | #include "includes.h" | |
31 | RCSID("$OpenBSD: auth-krb5.c,v 1.10 2002/11/21 23:03:51 deraadt Exp $"); | |
32 | ||
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> | |
44 | #ifndef HEIMDAL | |
45 | #define krb5_get_err_text(context,code) error_message(code) | |
46 | #endif /* !HEIMDAL */ | |
47 | ||
48 | extern ServerOptions options; | |
49 | ||
50 | static int | |
51 | krb5_init(void *context) | |
52 | { | |
53 | Authctxt *authctxt = (Authctxt *)context; | |
54 | krb5_error_code problem; | |
55 | static int cleanup_registered = 0; | |
56 | ||
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 | */ | |
75 | int | |
76 | auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *reply) | |
77 | { | |
78 | krb5_error_code problem; | |
79 | krb5_principal server; | |
80 | krb5_ticket *ticket; | |
81 | int fd, ret; | |
82 | ||
83 | ret = 0; | |
84 | server = NULL; | |
85 | ticket = NULL; | |
86 | reply->length = 0; | |
87 | ||
88 | problem = krb5_init(authctxt); | |
89 | if (problem) | |
90 | goto err; | |
91 | ||
92 | problem = krb5_auth_con_init(authctxt->krb5_ctx, | |
93 | &authctxt->krb5_auth_ctx); | |
94 | if (problem) | |
95 | goto err; | |
96 | ||
97 | fd = packet_get_connection_in(); | |
98 | #ifdef HEIMDAL | |
99 | problem = krb5_auth_con_setaddrs_from_fd(authctxt->krb5_ctx, | |
100 | authctxt->krb5_auth_ctx, &fd); | |
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 | |
107 | if (problem) | |
108 | goto err; | |
109 | ||
110 | problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, | |
111 | KRB5_NT_SRV_HST, &server); | |
112 | if (problem) | |
113 | goto err; | |
114 | ||
115 | problem = krb5_rd_req(authctxt->krb5_ctx, &authctxt->krb5_auth_ctx, | |
116 | auth, server, NULL, NULL, &ticket); | |
117 | if (problem) | |
118 | goto err; | |
119 | ||
120 | #ifdef HEIMDAL | |
121 | problem = krb5_copy_principal(authctxt->krb5_ctx, ticket->client, | |
122 | &authctxt->krb5_user); | |
123 | #else | |
124 | problem = krb5_copy_principal(authctxt->krb5_ctx, | |
125 | ticket->enc_part2->client, | |
126 | &authctxt->krb5_user); | |
127 | #endif | |
128 | if (problem) | |
129 | goto err; | |
130 | ||
131 | /* if client wants mutual auth */ | |
132 | problem = krb5_mk_rep(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, | |
133 | reply); | |
134 | if (problem) | |
135 | goto err; | |
136 | ||
137 | /* Check .k5login authorization now. */ | |
138 | if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, | |
139 | authctxt->pw->pw_name)) | |
140 | goto err; | |
141 | ||
142 | if (client) | |
143 | krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user, | |
144 | client); | |
145 | ||
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); | |
152 | if (!ret && reply->length) { | |
153 | xfree(reply->data); | |
154 | memset(reply, 0, sizeof(*reply)); | |
155 | } | |
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 | } | |
165 | ||
166 | return (ret); | |
167 | } | |
168 | ||
169 | int | |
170 | auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt) | |
171 | { | |
172 | krb5_error_code problem; | |
173 | krb5_ccache ccache = NULL; | |
174 | char *pname; | |
175 | krb5_creds **creds; | |
176 | ||
177 | if (authctxt->pw == NULL || authctxt->krb5_user == NULL) | |
178 | return (0); | |
179 | ||
180 | temporarily_use_uid(authctxt->pw); | |
181 | ||
182 | #ifdef HEIMDAL | |
183 | problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, &ccache); | |
184 | #else | |
185 | { | |
186 | char ccname[40]; | |
187 | int tmpfd; | |
188 | ||
189 | snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid()); | |
190 | ||
191 | if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) { | |
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); | |
203 | problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &ccache); | |
204 | } | |
205 | #endif | |
206 | if (problem) | |
207 | goto fail; | |
208 | ||
209 | problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, | |
210 | authctxt->krb5_user); | |
211 | if (problem) | |
212 | goto fail; | |
213 | ||
214 | #ifdef HEIMDAL | |
215 | problem = krb5_rd_cred2(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, | |
216 | ccache, tgt); | |
217 | if (problem) | |
218 | goto fail; | |
219 | #else | |
220 | problem = krb5_rd_cred(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, | |
221 | tgt, &creds, NULL); | |
222 | if (problem) | |
223 | goto fail; | |
224 | problem = krb5_cc_store_cred(authctxt->krb5_ctx, ccache, *creds); | |
225 | if (problem) | |
226 | goto fail; | |
227 | #endif | |
228 | ||
229 | authctxt->krb5_fwd_ccache = ccache; | |
230 | ccache = NULL; | |
231 | ||
232 | authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); | |
233 | ||
234 | problem = krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user, | |
235 | &pname); | |
236 | if (problem) | |
237 | goto fail; | |
238 | ||
239 | debug("Kerberos v5 TGT accepted (%s)", pname); | |
240 | ||
241 | restore_uid(); | |
242 | ||
243 | return (1); | |
244 | ||
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); | |
251 | ||
252 | restore_uid(); | |
253 | ||
254 | return (0); | |
255 | } | |
256 | ||
257 | int | |
258 | auth_krb5_password(Authctxt *authctxt, const char *password) | |
259 | { | |
260 | #ifndef HEIMDAL | |
261 | krb5_creds creds; | |
262 | krb5_principal server; | |
263 | char ccname[40]; | |
264 | int tmpfd; | |
265 | #endif | |
266 | krb5_error_code problem; | |
267 | ||
268 | if (authctxt->pw == NULL) | |
269 | return (0); | |
270 | ||
271 | temporarily_use_uid(authctxt->pw); | |
272 | ||
273 | problem = krb5_init(authctxt); | |
274 | if (problem) | |
275 | goto out; | |
276 | ||
277 | problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name, | |
278 | &authctxt->krb5_user); | |
279 | if (problem) | |
280 | goto out; | |
281 | ||
282 | #ifdef HEIMDAL | |
283 | problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, | |
284 | &authctxt->krb5_fwd_ccache); | |
285 | if (problem) | |
286 | goto out; | |
287 | ||
288 | problem = krb5_cc_initialize(authctxt->krb5_ctx, | |
289 | authctxt->krb5_fwd_ccache, authctxt->krb5_user); | |
290 | if (problem) | |
291 | goto out; | |
292 | ||
293 | restore_uid(); | |
294 | problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, | |
295 | authctxt->krb5_fwd_ccache, password, 1, NULL); | |
296 | temporarily_use_uid(authctxt->pw); | |
297 | ||
298 | if (problem) | |
299 | goto out; | |
300 | ||
301 | #else | |
302 | problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds, | |
303 | authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL); | |
304 | if (problem) | |
305 | goto out; | |
306 | ||
307 | problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, | |
308 | KRB5_NT_SRV_HST, &server); | |
309 | if (problem) | |
310 | goto out; | |
311 | ||
312 | restore_uid(); | |
313 | problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server, | |
314 | NULL, NULL, NULL); | |
315 | krb5_free_principal(authctxt->krb5_ctx, server); | |
316 | temporarily_use_uid(authctxt->pw); | |
317 | if (problem) | |
318 | goto out; | |
319 | ||
320 | if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, | |
321 | authctxt->pw->pw_name)) { | |
322 | problem = -1; | |
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; | |
331 | goto out; | |
332 | } | |
333 | ||
334 | if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { | |
335 | log("fchmod(): %.100s", strerror(errno)); | |
336 | close(tmpfd); | |
337 | problem = errno; | |
338 | goto out; | |
339 | } | |
340 | close(tmpfd); | |
341 | ||
342 | problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &authctxt->krb5_fwd_ccache); | |
343 | if (problem) | |
344 | goto out; | |
345 | ||
346 | problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, | |
347 | authctxt->krb5_user); | |
348 | if (problem) | |
349 | goto out; | |
350 | ||
351 | problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, | |
352 | &creds); | |
353 | if (problem) | |
354 | goto out; | |
355 | #endif | |
356 | ||
357 | authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); | |
358 | ||
359 | out: | |
360 | restore_uid(); | |
361 | ||
362 | if (problem) { | |
363 | if (authctxt->krb5_ctx != NULL && problem!=-1) | |
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 | ||
370 | krb5_cleanup_proc(authctxt); | |
371 | ||
372 | if (options.kerberos_or_local_passwd) | |
373 | return (-1); | |
374 | else | |
375 | return (0); | |
376 | } | |
377 | return (1); | |
378 | } | |
379 | ||
380 | void | |
381 | krb5_cleanup_proc(void *context) | |
382 | { | |
383 | Authctxt *authctxt = (Authctxt *)context; | |
384 | ||
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 */ |