1 /* $NetBSD: get_for_creds.c,v 1.3 2019/12/15 22:50:50 christos Exp $ */
2
3 /*
4 * Copyright (c) 1997 - 2004 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include "krb5_locl.h"
37
38 static krb5_error_code
add_addrs(krb5_context context,krb5_addresses * addr,struct addrinfo * ai)39 add_addrs(krb5_context context,
40 krb5_addresses *addr,
41 struct addrinfo *ai)
42 {
43 krb5_error_code ret;
44 unsigned n, i;
45 void *tmp;
46 struct addrinfo *a;
47
48 n = 0;
49 for (a = ai; a != NULL; a = a->ai_next)
50 ++n;
51
52 tmp = realloc(addr->val, (addr->len + n) * sizeof(*addr->val));
53 if (tmp == NULL && (addr->len + n) != 0) {
54 ret = krb5_enomem(context);
55 goto fail;
56 }
57 addr->val = tmp;
58 for (i = addr->len; i < (addr->len + n); ++i) {
59 addr->val[i].addr_type = 0;
60 krb5_data_zero(&addr->val[i].address);
61 }
62 i = addr->len;
63 for (a = ai; a != NULL; a = a->ai_next) {
64 krb5_address ad;
65
66 ret = krb5_sockaddr2address (context, a->ai_addr, &ad);
67 if (ret == 0) {
68 if (krb5_address_search(context, &ad, addr))
69 krb5_free_address(context, &ad);
70 else
71 addr->val[i++] = ad;
72 }
73 else if (ret == KRB5_PROG_ATYPE_NOSUPP)
74 krb5_clear_error_message (context);
75 else
76 goto fail;
77 addr->len = i;
78 }
79 return 0;
80 fail:
81 krb5_free_addresses (context, addr);
82 return ret;
83 }
84
85 /**
86 * Forward credentials for client to host hostname , making them
87 * forwardable if forwardable, and returning the blob of data to sent
88 * in out_data. If hostname == NULL, pick it from server.
89 *
90 * @param context A kerberos 5 context.
91 * @param auth_context the auth context with the key to encrypt the out_data.
92 * @param hostname the host to forward the tickets too.
93 * @param client the client to delegate from.
94 * @param server the server to delegate the credential too.
95 * @param ccache credential cache to use.
96 * @param forwardable make the forwarded ticket forwabledable.
97 * @param out_data the resulting credential.
98 *
99 * @return Return an error code or 0.
100 *
101 * @ingroup krb5_credential
102 */
103
104 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_fwd_tgt_creds(krb5_context context,krb5_auth_context auth_context,const char * hostname,krb5_principal client,krb5_principal server,krb5_ccache ccache,int forwardable,krb5_data * out_data)105 krb5_fwd_tgt_creds (krb5_context context,
106 krb5_auth_context auth_context,
107 const char *hostname,
108 krb5_principal client,
109 krb5_principal server,
110 krb5_ccache ccache,
111 int forwardable,
112 krb5_data *out_data)
113 {
114 krb5_flags flags = 0;
115 krb5_creds creds;
116 krb5_error_code ret;
117 krb5_const_realm client_realm;
118
119 flags |= KDC_OPT_FORWARDED;
120
121 if (forwardable)
122 flags |= KDC_OPT_FORWARDABLE;
123
124 if (hostname == NULL &&
125 krb5_principal_get_type(context, server) == KRB5_NT_SRV_HST) {
126 const char *inst = krb5_principal_get_comp_string(context, server, 0);
127 const char *host = krb5_principal_get_comp_string(context, server, 1);
128
129 if (inst != NULL &&
130 strcmp(inst, "host") == 0 &&
131 host != NULL &&
132 krb5_principal_get_comp_string(context, server, 2) == NULL)
133 hostname = host;
134 }
135
136 client_realm = krb5_principal_get_realm(context, client);
137
138 memset (&creds, 0, sizeof(creds));
139 creds.client = client;
140
141 ret = krb5_make_principal(context,
142 &creds.server,
143 client_realm,
144 KRB5_TGS_NAME,
145 client_realm,
146 NULL);
147 if (ret)
148 return ret;
149
150 ret = krb5_get_forwarded_creds (context,
151 auth_context,
152 ccache,
153 flags,
154 hostname,
155 &creds,
156 out_data);
157 return ret;
158 }
159
160 /**
161 * Gets tickets forwarded to hostname. If the tickets that are
162 * forwarded are address-less, the forwarded tickets will also be
163 * address-less.
164 *
165 * If the ticket have any address, hostname will be used for figure
166 * out the address to forward the ticket too. This since this might
167 * use DNS, its insecure and also doesn't represent configured all
168 * addresses of the host. For example, the host might have two
169 * adresses, one IPv4 and one IPv6 address where the later is not
170 * published in DNS. This IPv6 address might be used communications
171 * and thus the resulting ticket useless.
172 *
173 * @param context A kerberos 5 context.
174 * @param auth_context the auth context with the key to encrypt the out_data.
175 * @param ccache credential cache to use
176 * @param flags the flags to control the resulting ticket flags
177 * @param hostname the host to forward the tickets too.
178 * @param in_creds the in client and server ticket names. The client
179 * and server components forwarded to the remote host.
180 * @param out_data the resulting credential.
181 *
182 * @return Return an error code or 0.
183 *
184 * @ingroup krb5_credential
185 */
186
187 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_get_forwarded_creds(krb5_context context,krb5_auth_context auth_context,krb5_ccache ccache,krb5_flags flags,const char * hostname,krb5_creds * in_creds,krb5_data * out_data)188 krb5_get_forwarded_creds (krb5_context context,
189 krb5_auth_context auth_context,
190 krb5_ccache ccache,
191 krb5_flags flags,
192 const char *hostname,
193 krb5_creds *in_creds,
194 krb5_data *out_data)
195 {
196 krb5_error_code ret;
197 krb5_creds *out_creds;
198 krb5_addresses addrs, *paddrs;
199 KRB_CRED cred;
200 KrbCredInfo *krb_cred_info;
201 EncKrbCredPart enc_krb_cred_part;
202 size_t len;
203 unsigned char *buf;
204 size_t buf_size;
205 krb5_kdc_flags kdc_flags;
206 krb5_crypto crypto;
207 struct addrinfo *ai;
208 krb5_creds *ticket;
209
210 paddrs = NULL;
211 addrs.len = 0;
212 addrs.val = NULL;
213
214 ret = krb5_get_credentials(context, 0, ccache, in_creds, &ticket);
215 if(ret == 0) {
216 if (ticket->addresses.len)
217 paddrs = &addrs;
218 krb5_free_creds (context, ticket);
219 } else {
220 krb5_boolean noaddr;
221 krb5_appdefault_boolean(context, NULL,
222 krb5_principal_get_realm(context,
223 in_creds->client),
224 "no-addresses", KRB5_ADDRESSLESS_DEFAULT,
225 &noaddr);
226 if (!noaddr)
227 paddrs = &addrs;
228 }
229
230 /*
231 * If tickets have addresses, get the address of the remote host.
232 */
233
234 if (paddrs != NULL) {
235
236 ret = getaddrinfo (hostname, NULL, NULL, &ai);
237 if (ret) {
238 krb5_error_code ret2 = krb5_eai_to_heim_errno(ret, errno);
239 krb5_set_error_message(context, ret2,
240 N_("resolving host %s failed: %s",
241 "hostname, error"),
242 hostname, gai_strerror(ret));
243 return ret2;
244 }
245
246 ret = add_addrs (context, &addrs, ai);
247 freeaddrinfo (ai);
248 if (ret)
249 return ret;
250 }
251
252 kdc_flags.b = int2KDCOptions(flags);
253
254 ret = krb5_get_kdc_cred (context,
255 ccache,
256 kdc_flags,
257 paddrs,
258 NULL,
259 in_creds,
260 &out_creds);
261 krb5_free_addresses (context, &addrs);
262 if (ret)
263 return ret;
264
265 memset (&cred, 0, sizeof(cred));
266 cred.pvno = 5;
267 cred.msg_type = krb_cred;
268 ALLOC_SEQ(&cred.tickets, 1);
269 if (cred.tickets.val == NULL) {
270 ret = krb5_enomem(context);
271 goto out2;
272 }
273 ret = decode_Ticket(out_creds->ticket.data,
274 out_creds->ticket.length,
275 cred.tickets.val, &len);
276 if (ret)
277 goto out3;
278
279 memset (&enc_krb_cred_part, 0, sizeof(enc_krb_cred_part));
280 ALLOC_SEQ(&enc_krb_cred_part.ticket_info, 1);
281 if (enc_krb_cred_part.ticket_info.val == NULL) {
282 ret = krb5_enomem(context);
283 goto out4;
284 }
285
286 if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
287 krb5_timestamp sec;
288 int32_t usec;
289
290 krb5_us_timeofday (context, &sec, &usec);
291
292 ALLOC(enc_krb_cred_part.timestamp, 1);
293 if (enc_krb_cred_part.timestamp == NULL) {
294 ret = krb5_enomem(context);
295 goto out4;
296 }
297 *enc_krb_cred_part.timestamp = sec;
298 ALLOC(enc_krb_cred_part.usec, 1);
299 if (enc_krb_cred_part.usec == NULL) {
300 ret = krb5_enomem(context);
301 goto out4;
302 }
303 *enc_krb_cred_part.usec = usec;
304 } else {
305 enc_krb_cred_part.timestamp = NULL;
306 enc_krb_cred_part.usec = NULL;
307 }
308
309 if (auth_context->local_address && auth_context->local_port && paddrs) {
310
311 ret = krb5_make_addrport (context,
312 &enc_krb_cred_part.s_address,
313 auth_context->local_address,
314 auth_context->local_port);
315 if (ret)
316 goto out4;
317 }
318
319 if (auth_context->remote_address) {
320 if (auth_context->remote_port) {
321 krb5_boolean noaddr;
322 krb5_const_realm srealm;
323
324 srealm = krb5_principal_get_realm(context, out_creds->server);
325 /* Is this correct, and should we use the paddrs == NULL
326 trick here as well? Having an address-less ticket may
327 indicate that we don't know our own global address, but
328 it does not necessary mean that we don't know the
329 server's. */
330 krb5_appdefault_boolean(context, NULL, srealm, "no-addresses",
331 FALSE, &noaddr);
332 if (!noaddr) {
333 ret = krb5_make_addrport (context,
334 &enc_krb_cred_part.r_address,
335 auth_context->remote_address,
336 auth_context->remote_port);
337 if (ret)
338 goto out4;
339 }
340 } else {
341 ALLOC(enc_krb_cred_part.r_address, 1);
342 if (enc_krb_cred_part.r_address == NULL) {
343 ret = krb5_enomem(context);
344 goto out4;
345 }
346
347 ret = krb5_copy_address (context, auth_context->remote_address,
348 enc_krb_cred_part.r_address);
349 if (ret)
350 goto out4;
351 }
352 }
353
354 /* fill ticket_info.val[0] */
355
356 enc_krb_cred_part.ticket_info.len = 1;
357
358 krb_cred_info = enc_krb_cred_part.ticket_info.val;
359
360 ret = copy_EncryptionKey (&out_creds->session, &krb_cred_info->key);
361 if (ret)
362 goto out4;
363 ALLOC(krb_cred_info->prealm, 1);
364 ret = copy_Realm (&out_creds->client->realm, krb_cred_info->prealm);
365 if (ret)
366 goto out4;
367 ALLOC(krb_cred_info->pname, 1);
368 ret = copy_PrincipalName(&out_creds->client->name, krb_cred_info->pname);
369 if (ret)
370 goto out4;
371 ALLOC(krb_cred_info->flags, 1);
372 *krb_cred_info->flags = out_creds->flags.b;
373 ALLOC(krb_cred_info->authtime, 1);
374 *krb_cred_info->authtime = out_creds->times.authtime;
375 ALLOC(krb_cred_info->starttime, 1);
376 *krb_cred_info->starttime = out_creds->times.starttime;
377 ALLOC(krb_cred_info->endtime, 1);
378 *krb_cred_info->endtime = out_creds->times.endtime;
379 ALLOC(krb_cred_info->renew_till, 1);
380 *krb_cred_info->renew_till = out_creds->times.renew_till;
381 ALLOC(krb_cred_info->srealm, 1);
382 ret = copy_Realm (&out_creds->server->realm, krb_cred_info->srealm);
383 if (ret)
384 goto out4;
385 ALLOC(krb_cred_info->sname, 1);
386 ret = copy_PrincipalName (&out_creds->server->name, krb_cred_info->sname);
387 if (ret)
388 goto out4;
389 ALLOC(krb_cred_info->caddr, 1);
390 ret = copy_HostAddresses (&out_creds->addresses, krb_cred_info->caddr);
391 if (ret)
392 goto out4;
393
394 krb5_free_creds (context, out_creds);
395
396 /* encode EncKrbCredPart */
397
398 ASN1_MALLOC_ENCODE(EncKrbCredPart, buf, buf_size,
399 &enc_krb_cred_part, &len, ret);
400 free_EncKrbCredPart (&enc_krb_cred_part);
401 if (ret) {
402 free_KRB_CRED(&cred);
403 return ret;
404 }
405 if(buf_size != len)
406 krb5_abortx(context, "internal error in ASN.1 encoder");
407
408 /**
409 * Some older of the MIT gssapi library used clear-text tickets
410 * (warped inside AP-REQ encryption), use the krb5_auth_context
411 * flag KRB5_AUTH_CONTEXT_CLEAR_FORWARDED_CRED to support those
412 * tickets. The session key is used otherwise to encrypt the
413 * forwarded ticket.
414 */
415
416 if (auth_context->flags & KRB5_AUTH_CONTEXT_CLEAR_FORWARDED_CRED) {
417 cred.enc_part.etype = KRB5_ENCTYPE_NULL;
418 cred.enc_part.kvno = NULL;
419 cred.enc_part.cipher.data = buf;
420 cred.enc_part.cipher.length = buf_size;
421 } else {
422 /*
423 * Here older versions then 0.7.2 of Heimdal used the local or
424 * remote subkey. That is wrong, the session key should be
425 * used. Heimdal 0.7.2 and newer have code to try both in the
426 * receiving end.
427 */
428
429 ret = krb5_crypto_init(context, auth_context->keyblock, 0, &crypto);
430 if (ret) {
431 free(buf);
432 free_KRB_CRED(&cred);
433 return ret;
434 }
435 ret = krb5_encrypt_EncryptedData (context,
436 crypto,
437 KRB5_KU_KRB_CRED,
438 buf,
439 len,
440 0,
441 &cred.enc_part);
442 free(buf);
443 krb5_crypto_destroy(context, crypto);
444 if (ret) {
445 free_KRB_CRED(&cred);
446 return ret;
447 }
448 }
449
450 ASN1_MALLOC_ENCODE(KRB_CRED, buf, buf_size, &cred, &len, ret);
451 free_KRB_CRED (&cred);
452 if (ret)
453 return ret;
454 if(buf_size != len)
455 krb5_abortx(context, "internal error in ASN.1 encoder");
456 out_data->length = len;
457 out_data->data = buf;
458 return 0;
459 out4:
460 free_EncKrbCredPart(&enc_krb_cred_part);
461 out3:
462 free_KRB_CRED(&cred);
463 out2:
464 krb5_free_creds (context, out_creds);
465 return ret;
466 }
467