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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" | |
762715ce | 31 | RCSID("$OpenBSD: auth-krb5.c,v 1.8 2002/03/19 10:49:35 markus 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 | |
43 | #include <krb5.h> | |
12928e80 | 44 | #ifndef HEIMDAL |
45 | #define krb5_get_err_text(context,code) error_message(code) | |
46 | #endif /* !HEIMDAL */ | |
aa9f6a6e | 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; | |
a0105740 | 56 | |
aa9f6a6e | 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 | */ | |
a0105740 | 75 | int |
aa9f6a6e | 76 | auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client) |
77 | { | |
78 | krb5_error_code problem; | |
79 | krb5_principal server; | |
80 | krb5_data reply; | |
81 | krb5_ticket *ticket; | |
ede8cea6 | 82 | int fd, ret; |
83 | ||
84 | ret = 0; | |
aa9f6a6e | 85 | server = NULL; |
86 | ticket = NULL; | |
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 | |
aa9f6a6e | 111 | problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL , |
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, | |
134 | &reply); | |
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 | |
aa9f6a6e | 147 | packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE); |
148 | packet_put_string((char *) reply.data, reply.length); | |
149 | packet_send(); | |
150 | packet_write_wait(); | |
ede8cea6 | 151 | |
152 | ret = 1; | |
aa9f6a6e | 153 | err: |
154 | if (server) | |
155 | krb5_free_principal(authctxt->krb5_ctx, server); | |
156 | if (ticket) | |
157 | krb5_free_ticket(authctxt->krb5_ctx, ticket); | |
158 | if (reply.length) | |
159 | xfree(reply.data); | |
a0105740 | 160 | |
c12337d9 | 161 | if (problem) { |
162 | if (authctxt->krb5_ctx != NULL) | |
163 | debug("Kerberos v5 authentication failed: %s", | |
164 | krb5_get_err_text(authctxt->krb5_ctx, problem)); | |
165 | else | |
166 | debug("Kerberos v5 authentication failed: %d", | |
167 | problem); | |
168 | } | |
ede8cea6 | 169 | |
170 | return (ret); | |
aa9f6a6e | 171 | } |
172 | ||
173 | int | |
174 | auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt) | |
175 | { | |
176 | krb5_error_code problem; | |
177 | krb5_ccache ccache = NULL; | |
178 | char *pname; | |
12928e80 | 179 | krb5_creds **creds; |
a0105740 | 180 | |
aa9f6a6e | 181 | if (authctxt->pw == NULL || authctxt->krb5_user == NULL) |
182 | return (0); | |
a0105740 | 183 | |
aa9f6a6e | 184 | temporarily_use_uid(authctxt->pw); |
a0105740 | 185 | |
12928e80 | 186 | #ifdef HEIMDAL |
aa9f6a6e | 187 | problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, &ccache); |
12928e80 | 188 | #else |
189 | { | |
190 | char ccname[40]; | |
191 | int tmpfd; | |
192 | ||
193 | snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid()); | |
194 | ||
195 | if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) { | |
196 | log("mkstemp(): %.100s", strerror(errno)); | |
197 | problem = errno; | |
198 | goto fail; | |
199 | } | |
200 | if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { | |
201 | log("fchmod(): %.100s", strerror(errno)); | |
202 | close(tmpfd); | |
203 | problem = errno; | |
204 | goto fail; | |
205 | } | |
206 | close(tmpfd); | |
207 | problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &ccache); | |
208 | } | |
209 | #endif | |
aa9f6a6e | 210 | if (problem) |
211 | goto fail; | |
a0105740 | 212 | |
aa9f6a6e | 213 | problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, |
214 | authctxt->krb5_user); | |
215 | if (problem) | |
216 | goto fail; | |
a0105740 | 217 | |
12928e80 | 218 | #ifdef HEIMDAL |
aa9f6a6e | 219 | problem = krb5_rd_cred2(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, |
220 | ccache, tgt); | |
221 | if (problem) | |
222 | goto fail; | |
12928e80 | 223 | #else |
224 | problem = krb5_rd_cred(authctxt->krb5_ctx, authctxt->krb5_auth_ctx, | |
225 | tgt, &creds, NULL); | |
226 | if (problem) | |
227 | goto fail; | |
228 | problem = krb5_cc_store_cred(authctxt->krb5_ctx, ccache, *creds); | |
229 | if (problem) | |
230 | goto fail; | |
231 | #endif | |
a0105740 | 232 | |
aa9f6a6e | 233 | authctxt->krb5_fwd_ccache = ccache; |
234 | ccache = NULL; | |
a0105740 | 235 | |
aa9f6a6e | 236 | authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); |
a0105740 | 237 | |
aa9f6a6e | 238 | problem = krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user, |
239 | &pname); | |
240 | if (problem) | |
241 | goto fail; | |
a0105740 | 242 | |
aa9f6a6e | 243 | debug("Kerberos v5 TGT accepted (%s)", pname); |
a0105740 | 244 | |
aa9f6a6e | 245 | restore_uid(); |
a0105740 | 246 | |
aa9f6a6e | 247 | return (1); |
a0105740 | 248 | |
aa9f6a6e | 249 | fail: |
250 | if (problem) | |
251 | debug("Kerberos v5 TGT passing failed: %s", | |
252 | krb5_get_err_text(authctxt->krb5_ctx, problem)); | |
253 | if (ccache) | |
254 | krb5_cc_destroy(authctxt->krb5_ctx, ccache); | |
a0105740 | 255 | |
aa9f6a6e | 256 | restore_uid(); |
a0105740 | 257 | |
aa9f6a6e | 258 | return (0); |
259 | } | |
260 | ||
261 | int | |
262 | auth_krb5_password(Authctxt *authctxt, const char *password) | |
263 | { | |
12928e80 | 264 | #ifndef HEIMDAL |
265 | krb5_creds creds; | |
266 | krb5_principal server; | |
267 | char ccname[40]; | |
268 | int tmpfd; | |
269 | #endif | |
aa9f6a6e | 270 | krb5_error_code problem; |
a0105740 | 271 | |
aa9f6a6e | 272 | if (authctxt->pw == NULL) |
273 | return (0); | |
a0105740 | 274 | |
aa9f6a6e | 275 | temporarily_use_uid(authctxt->pw); |
a0105740 | 276 | |
aa9f6a6e | 277 | problem = krb5_init(authctxt); |
278 | if (problem) | |
279 | goto out; | |
a0105740 | 280 | |
aa9f6a6e | 281 | problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name, |
282 | &authctxt->krb5_user); | |
283 | if (problem) | |
284 | goto out; | |
a0105740 | 285 | |
12928e80 | 286 | #ifdef HEIMDAL |
aa9f6a6e | 287 | problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, |
288 | &authctxt->krb5_fwd_ccache); | |
289 | if (problem) | |
290 | goto out; | |
a0105740 | 291 | |
aa9f6a6e | 292 | problem = krb5_cc_initialize(authctxt->krb5_ctx, |
293 | authctxt->krb5_fwd_ccache, authctxt->krb5_user); | |
294 | if (problem) | |
295 | goto out; | |
a0105740 | 296 | |
297 | restore_uid(); | |
aa9f6a6e | 298 | problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, |
299 | authctxt->krb5_fwd_ccache, password, 1, NULL); | |
a0105740 | 300 | temporarily_use_uid(authctxt->pw); |
301 | ||
aa9f6a6e | 302 | if (problem) |
303 | goto out; | |
a0105740 | 304 | |
12928e80 | 305 | #else |
306 | problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds, | |
307 | authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL); | |
308 | if (problem) | |
309 | goto out; | |
310 | ||
311 | problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, | |
312 | KRB5_NT_SRV_HST, &server); | |
313 | if (problem) | |
314 | goto out; | |
315 | ||
316 | restore_uid(); | |
317 | problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server, | |
318 | NULL, NULL, NULL); | |
319 | krb5_free_principal(authctxt->krb5_ctx, server); | |
320 | temporarily_use_uid(authctxt->pw); | |
321 | if (problem) | |
322 | goto out; | |
323 | ||
324 | if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, | |
325 | authctxt->pw->pw_name)) { | |
326 | problem = -1; | |
327 | goto out; | |
328 | } | |
329 | ||
330 | snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid()); | |
331 | ||
332 | if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) { | |
333 | log("mkstemp(): %.100s", strerror(errno)); | |
334 | problem = errno; | |
335 | goto out; | |
336 | } | |
337 | ||
338 | if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { | |
339 | log("fchmod(): %.100s", strerror(errno)); | |
340 | close(tmpfd); | |
341 | problem = errno; | |
342 | goto out; | |
343 | } | |
344 | close(tmpfd); | |
345 | ||
346 | problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &authctxt->krb5_fwd_ccache); | |
347 | if (problem) | |
348 | goto out; | |
349 | ||
350 | problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, | |
351 | authctxt->krb5_user); | |
352 | if (problem) | |
353 | goto out; | |
354 | ||
355 | problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, | |
356 | &creds); | |
357 | if (problem) | |
358 | goto out; | |
359 | #endif | |
360 | ||
aa9f6a6e | 361 | authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); |
a0105740 | 362 | |
aa9f6a6e | 363 | out: |
364 | restore_uid(); | |
a0105740 | 365 | |
aa9f6a6e | 366 | if (problem) { |
12928e80 | 367 | if (authctxt->krb5_ctx != NULL && problem!=-1) |
c12337d9 | 368 | debug("Kerberos password authentication failed: %s", |
369 | krb5_get_err_text(authctxt->krb5_ctx, problem)); | |
370 | else | |
371 | debug("Kerberos password authentication failed: %d", | |
372 | problem); | |
a0105740 | 373 | |
aa9f6a6e | 374 | krb5_cleanup_proc(authctxt); |
a0105740 | 375 | |
aa9f6a6e | 376 | if (options.kerberos_or_local_passwd) |
377 | return (-1); | |
378 | else | |
379 | return (0); | |
380 | } | |
381 | return (1); | |
382 | } | |
383 | ||
384 | void | |
385 | krb5_cleanup_proc(void *context) | |
386 | { | |
387 | Authctxt *authctxt = (Authctxt *)context; | |
a0105740 | 388 | |
aa9f6a6e | 389 | debug("krb5_cleanup_proc called"); |
390 | if (authctxt->krb5_fwd_ccache) { | |
391 | krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); | |
392 | authctxt->krb5_fwd_ccache = NULL; | |
393 | } | |
394 | if (authctxt->krb5_user) { | |
395 | krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); | |
396 | authctxt->krb5_user = NULL; | |
397 | } | |
398 | if (authctxt->krb5_auth_ctx) { | |
399 | krb5_auth_con_free(authctxt->krb5_ctx, | |
400 | authctxt->krb5_auth_ctx); | |
401 | authctxt->krb5_auth_ctx = NULL; | |
402 | } | |
403 | if (authctxt->krb5_ctx) { | |
404 | krb5_free_context(authctxt->krb5_ctx); | |
405 | authctxt->krb5_ctx = NULL; | |
406 | } | |
407 | } | |
408 | ||
409 | #endif /* KRB5 */ |