1/*	$NetBSD: rd_cred.c,v 1.3 2019/12/15 22:50:50 christos Exp $	*/
2
3/*
4 * Copyright (c) 1997 - 2007 Kungliga Tekniska H��gskolan
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
38static krb5_error_code
39compare_addrs(krb5_context context,
40	      krb5_address *a,
41	      krb5_address *b,
42	      const char *message)
43{
44    char a_str[64], b_str[64];
45    size_t len;
46
47    if(krb5_address_compare (context, a, b))
48	return 0;
49
50    krb5_print_address (a, a_str, sizeof(a_str), &len);
51    krb5_print_address (b, b_str, sizeof(b_str), &len);
52    krb5_set_error_message(context, KRB5KRB_AP_ERR_BADADDR,
53			   "%s: %s != %s", message, b_str, a_str);
54    return KRB5KRB_AP_ERR_BADADDR;
55}
56
57KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
58krb5_rd_cred(krb5_context context,
59	     krb5_auth_context auth_context,
60	     krb5_data *in_data,
61	     krb5_creds ***ret_creds,
62	     krb5_replay_data *outdata)
63{
64    krb5_error_code ret;
65    size_t len;
66    KRB_CRED cred;
67    EncKrbCredPart enc_krb_cred_part;
68    krb5_data enc_krb_cred_part_data;
69    krb5_crypto crypto;
70    size_t i;
71
72    memset(&enc_krb_cred_part, 0, sizeof(enc_krb_cred_part));
73    krb5_data_zero(&enc_krb_cred_part_data);
74
75    if ((auth_context->flags &
76	 (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
77	outdata == NULL)
78	return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */
79
80    *ret_creds = NULL;
81
82    ret = decode_KRB_CRED(in_data->data, in_data->length,
83			  &cred, &len);
84    if(ret) {
85	krb5_clear_error_message(context);
86	return ret;
87    }
88
89    if (cred.pvno != 5) {
90	ret = KRB5KRB_AP_ERR_BADVERSION;
91	krb5_clear_error_message (context);
92	goto out;
93    }
94
95    if (cred.msg_type != krb_cred) {
96	ret = KRB5KRB_AP_ERR_MSG_TYPE;
97	krb5_clear_error_message (context);
98	goto out;
99    }
100
101    if (cred.enc_part.etype == (krb5_enctype)ETYPE_NULL) {
102	/* DK: MIT GSS-API Compatibility */
103	enc_krb_cred_part_data.length = cred.enc_part.cipher.length;
104	enc_krb_cred_part_data.data   = cred.enc_part.cipher.data;
105    } else {
106	/* Try both subkey and session key.
107	 *
108	 * RFC4120 claims we should use the session key, but Heimdal
109	 * before 0.8 used the remote subkey if it was send in the
110	 * auth_context.
111	 */
112
113	if (auth_context->remote_subkey) {
114	    ret = krb5_crypto_init(context, auth_context->remote_subkey,
115				   0, &crypto);
116	    if (ret)
117		goto out;
118
119	    ret = krb5_decrypt_EncryptedData(context,
120					     crypto,
121					     KRB5_KU_KRB_CRED,
122					     &cred.enc_part,
123					     &enc_krb_cred_part_data);
124
125	    krb5_crypto_destroy(context, crypto);
126	}
127
128	/*
129	 * If there was not subkey, or we failed using subkey,
130	 * retry using the session key
131	 */
132	if (auth_context->remote_subkey == NULL || ret == KRB5KRB_AP_ERR_BAD_INTEGRITY)
133	{
134
135	    ret = krb5_crypto_init(context, auth_context->keyblock,
136				   0, &crypto);
137
138	    if (ret)
139		goto out;
140
141	    ret = krb5_decrypt_EncryptedData(context,
142					     crypto,
143					     KRB5_KU_KRB_CRED,
144					     &cred.enc_part,
145					     &enc_krb_cred_part_data);
146
147	    krb5_crypto_destroy(context, crypto);
148	}
149	if (ret)
150	    goto out;
151    }
152
153    ret = decode_EncKrbCredPart(enc_krb_cred_part_data.data,
154				enc_krb_cred_part_data.length,
155				&enc_krb_cred_part,
156				&len);
157    if (enc_krb_cred_part_data.data != cred.enc_part.cipher.data)
158	krb5_data_free(&enc_krb_cred_part_data);
159    if (ret) {
160	krb5_set_error_message(context, ret,
161			       N_("Failed to decode "
162				  "encrypte credential part", ""));
163	goto out;
164    }
165
166    /* check sender address */
167
168    if (enc_krb_cred_part.s_address
169	&& auth_context->remote_address
170	&& auth_context->remote_port) {
171	krb5_address *a;
172
173	ret = krb5_make_addrport (context, &a,
174				  auth_context->remote_address,
175				  auth_context->remote_port);
176	if (ret)
177	    goto out;
178
179
180	ret = compare_addrs(context, a, enc_krb_cred_part.s_address,
181			    N_("sender address is wrong "
182			       "in received creds", ""));
183	krb5_free_address(context, a);
184	free(a);
185	if(ret)
186	    goto out;
187    }
188
189    /* check receiver address */
190
191    if (enc_krb_cred_part.r_address
192	&& auth_context->local_address) {
193	if(auth_context->local_port &&
194	   enc_krb_cred_part.r_address->addr_type == KRB5_ADDRESS_ADDRPORT) {
195	    krb5_address *a;
196	    ret = krb5_make_addrport (context, &a,
197				      auth_context->local_address,
198				      auth_context->local_port);
199	    if (ret)
200		goto out;
201
202	    ret = compare_addrs(context, a, enc_krb_cred_part.r_address,
203				N_("receiver address is wrong "
204				   "in received creds", ""));
205	    krb5_free_address(context, a);
206	    free(a);
207	    if(ret)
208		goto out;
209	} else {
210	    ret = compare_addrs(context, auth_context->local_address,
211				enc_krb_cred_part.r_address,
212				N_("receiver address is wrong "
213				   "in received creds", ""));
214	    if(ret)
215		goto out;
216	}
217    }
218
219    /* check timestamp */
220    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
221	krb5_timestamp sec;
222
223	krb5_timeofday (context, &sec);
224
225	if (enc_krb_cred_part.timestamp == NULL ||
226	    enc_krb_cred_part.usec      == NULL ||
227	    labs(*enc_krb_cred_part.timestamp - sec)
228	    > context->max_skew) {
229	    krb5_clear_error_message (context);
230	    ret = KRB5KRB_AP_ERR_SKEW;
231	    goto out;
232	}
233    }
234
235    if ((auth_context->flags &
236	 (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) {
237	/* if these fields are not present in the cred-part, silently
238           return zero */
239	memset(outdata, 0, sizeof(*outdata));
240	if(enc_krb_cred_part.timestamp)
241	    outdata->timestamp = *enc_krb_cred_part.timestamp;
242	if(enc_krb_cred_part.usec)
243	    outdata->usec = *enc_krb_cred_part.usec;
244	if(enc_krb_cred_part.nonce)
245	    outdata->seq = *enc_krb_cred_part.nonce;
246    }
247
248    /* Convert to NULL terminated list of creds */
249
250    *ret_creds = calloc(enc_krb_cred_part.ticket_info.len + 1,
251			sizeof(**ret_creds));
252
253    if (*ret_creds == NULL) {
254	ret = krb5_enomem(context);
255	goto out;
256    }
257
258    for (i = 0; i < enc_krb_cred_part.ticket_info.len; ++i) {
259	KrbCredInfo *kci = &enc_krb_cred_part.ticket_info.val[i];
260	krb5_creds *creds;
261
262	creds = calloc(1, sizeof(*creds));
263	if(creds == NULL) {
264	    ret = krb5_enomem(context);
265	    goto out;
266	}
267
268	ASN1_MALLOC_ENCODE(Ticket, creds->ticket.data, creds->ticket.length,
269			   &cred.tickets.val[i], &len, ret);
270	if (ret) {
271	    free(creds);
272	    goto out;
273	}
274	if(creds->ticket.length != len)
275	    krb5_abortx(context, "internal error in ASN.1 encoder");
276	ret = copy_EncryptionKey (&kci->key, &creds->session);
277	if (ret) {
278	    krb5_free_creds(context, creds);
279	    goto out;
280	}
281	if (kci->prealm && kci->pname)
282	    _krb5_principalname2krb5_principal (context,
283						&creds->client,
284						*kci->pname,
285						*kci->prealm);
286	if (kci->flags)
287	    creds->flags.b = *kci->flags;
288	if (kci->authtime)
289	    creds->times.authtime = *kci->authtime;
290	if (kci->starttime)
291	    creds->times.starttime = *kci->starttime;
292	if (kci->endtime)
293	    creds->times.endtime = *kci->endtime;
294	if (kci->renew_till)
295	    creds->times.renew_till = *kci->renew_till;
296	if (kci->srealm && kci->sname)
297	    _krb5_principalname2krb5_principal (context,
298						&creds->server,
299						*kci->sname,
300						*kci->srealm);
301	if (kci->caddr)
302	    krb5_copy_addresses (context,
303				 kci->caddr,
304				 &creds->addresses);
305
306	(*ret_creds)[i] = creds;
307
308    }
309    (*ret_creds)[i] = NULL;
310
311    free_KRB_CRED (&cred);
312    free_EncKrbCredPart(&enc_krb_cred_part);
313
314    return 0;
315
316  out:
317    free_EncKrbCredPart(&enc_krb_cred_part);
318    free_KRB_CRED (&cred);
319    if(*ret_creds) {
320	for(i = 0; (*ret_creds)[i]; i++)
321	    krb5_free_creds(context, (*ret_creds)[i]);
322	free(*ret_creds);
323	*ret_creds = NULL;
324    }
325    return ret;
326}
327
328KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
329krb5_rd_cred2 (krb5_context      context,
330	       krb5_auth_context auth_context,
331	       krb5_ccache       ccache,
332	       krb5_data         *in_data)
333{
334    krb5_error_code ret;
335    krb5_creds **creds;
336    int i;
337
338    ret = krb5_rd_cred(context, auth_context, in_data, &creds, NULL);
339    if(ret)
340	return ret;
341
342    /* Store the creds in the ccache */
343
344    for(i = 0; creds && creds[i]; i++) {
345	krb5_cc_store_cred(context, ccache, creds[i]);
346	krb5_free_creds(context, creds[i]);
347    }
348    free(creds);
349    return 0;
350}
351