1
2/*
3 * Copyright (c) 1997 - 2001, 2003 - 2004 Kungliga Tekniska Högskolan
4 * (Royal Institute of Technology, Stockholm, Sweden).
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 *
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 * 3. Neither the name of the Institute nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include "hdb_locl.h"
36
37/*
38 * free all the memory used by (len, keys)
39 */
40
41void
42hdb_free_keys (krb5_context context, int len, Key *keys)
43{
44    int i;
45
46    for (i = 0; i < len; i++) {
47	free(keys[i].mkvno);
48	keys[i].mkvno = NULL;
49	if (keys[i].salt != NULL) {
50	    free_Salt(keys[i].salt);
51	    free(keys[i].salt);
52	    keys[i].salt = NULL;
53	}
54	krb5_free_keyblock_contents(context, &keys[i].key);
55    }
56    free (keys);
57}
58
59/*
60 * for each entry in `default_keys' try to parse it as a sequence
61 * of etype:salttype:salt, syntax of this if something like:
62 * [(des|des3|etype):](pw-salt|afs3)[:string], if etype is omitted it
63 *      means all etypes, and if string is omitted is means the default
64 * string (for that principal). Additional special values:
65 *	v5 == pw-salt, and
66 *	v4 == des:pw-salt:
67 *	afs or afs3 == des:afs3-salt
68 */
69
70static const krb5_enctype des_etypes[] = {
71    ETYPE_DES_CBC_MD5,
72    ETYPE_DES_CBC_MD4,
73    ETYPE_DES_CBC_CRC
74};
75
76static const krb5_enctype all_etypes[] = {
77    ETYPE_AES256_CTS_HMAC_SHA1_96,
78    ETYPE_ARCFOUR_HMAC_MD5,
79    ETYPE_DES3_CBC_SHA1
80};
81
82static krb5_error_code
83parse_key_set(krb5_context context, const char *key,
84	      krb5_enctype **ret_enctypes, size_t *ret_num_enctypes,
85	      krb5_salt *salt, krb5_principal principal)
86{
87    const char *p;
88    char buf[3][256];
89    int num_buf = 0;
90    int i, num_enctypes = 0;
91    krb5_enctype e;
92    const krb5_enctype *enctypes = NULL;
93    krb5_error_code ret;
94
95    p = key;
96
97    *ret_enctypes = NULL;
98    *ret_num_enctypes = 0;
99
100    /* split p in a list of :-separated strings */
101    for(num_buf = 0; num_buf < 3; num_buf++)
102	if(strsep_copy(&p, ":", buf[num_buf], sizeof(buf[num_buf])) == -1)
103	    break;
104
105    salt->saltvalue.data = NULL;
106    salt->saltvalue.length = 0;
107
108    for(i = 0; i < num_buf; i++) {
109	if(enctypes == NULL && num_buf > 1) {
110	    /* this might be a etype specifier */
111	    /* XXX there should be a string_to_etypes handling
112	       special cases like `des' and `all' */
113	    if(strcmp(buf[i], "des") == 0) {
114		enctypes = des_etypes;
115		num_enctypes = sizeof(des_etypes)/sizeof(des_etypes[0]);
116	    } else if(strcmp(buf[i], "des3") == 0) {
117		e = ETYPE_DES3_CBC_SHA1;
118		enctypes = &e;
119		num_enctypes = 1;
120	    } else {
121		ret = krb5_string_to_enctype(context, buf[i], &e);
122		if (ret == 0) {
123		    enctypes = &e;
124		    num_enctypes = 1;
125		} else
126		    return ret;
127	    }
128	    continue;
129	}
130	if(salt->salttype == 0) {
131	    /* interpret string as a salt specifier, if no etype
132	       is set, this sets default values */
133	    /* XXX should perhaps use string_to_salttype, but that
134	       interface sucks */
135	    if(strcmp(buf[i], "pw-salt") == 0) {
136		if(enctypes == NULL) {
137		    enctypes = all_etypes;
138		    num_enctypes = sizeof(all_etypes)/sizeof(all_etypes[0]);
139		}
140		salt->salttype = KRB5_PW_SALT;
141	    } else if(strcmp(buf[i], "afs3-salt") == 0) {
142		if(enctypes == NULL) {
143		    enctypes = des_etypes;
144		    num_enctypes = sizeof(des_etypes)/sizeof(des_etypes[0]);
145		}
146		salt->salttype = KRB5_AFS3_SALT;
147	    }
148	    continue;
149	}
150
151	{
152	    /* if there is a final string, use it as the string to
153	       salt with, this is mostly useful with null salt for
154	       v4 compat, and a cell name for afs compat */
155	    salt->saltvalue.data = strdup(buf[i]);
156	    if (salt->saltvalue.data == NULL) {
157		krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
158		return ENOMEM;
159	    }
160	    salt->saltvalue.length = strlen(buf[i]);
161	}
162    }
163
164    if(enctypes == NULL || salt->salttype == 0) {
165	krb5_set_error_message(context, EINVAL, "bad value for default_keys `%s'", key);
166	return EINVAL;
167    }
168
169    /* if no salt was specified make up default salt */
170    if(salt->saltvalue.data == NULL) {
171	if(salt->salttype == KRB5_PW_SALT)
172	    ret = krb5_get_pw_salt(context, principal, salt);
173	else if(salt->salttype == KRB5_AFS3_SALT) {
174	    krb5_const_realm realm = krb5_principal_get_realm(context, principal);
175	    salt->saltvalue.data = strdup(realm);
176	    if(salt->saltvalue.data == NULL) {
177		krb5_set_error_message(context, ENOMEM,
178				       "out of memory while "
179				       "parsing salt specifiers");
180		return ENOMEM;
181	    }
182	    strlwr(salt->saltvalue.data);
183	    salt->saltvalue.length = strlen(realm);
184	}
185    }
186
187    *ret_enctypes = malloc(sizeof(enctypes[0]) * num_enctypes);
188    if (*ret_enctypes == NULL) {
189	krb5_free_salt(context, *salt);
190	krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
191	return ENOMEM;
192    }
193    memcpy(*ret_enctypes, enctypes, sizeof(enctypes[0]) * num_enctypes);
194    *ret_num_enctypes = num_enctypes;
195
196    return 0;
197}
198
199static krb5_error_code
200add_enctype_to_key_set(Key **key_set, size_t *nkeyset,
201		       krb5_enctype enctype, krb5_salt *salt)
202{
203    krb5_error_code ret;
204    Key key, *tmp;
205
206    memset(&key, 0, sizeof(key));
207
208    tmp = realloc(*key_set, (*nkeyset + 1) * sizeof((*key_set)[0]));
209    if (tmp == NULL)
210	return ENOMEM;
211
212    *key_set = tmp;
213
214    key.key.keytype = enctype;
215    key.key.keyvalue.length = 0;
216    key.key.keyvalue.data = NULL;
217
218    if (salt) {
219	key.salt = calloc(1, sizeof(*key.salt));
220	if (key.salt == NULL) {
221	    free_Key(&key);
222	    return ENOMEM;
223	}
224
225	key.salt->type = salt->salttype;
226	krb5_data_zero (&key.salt->salt);
227
228	ret = krb5_data_copy(&key.salt->salt,
229			     salt->saltvalue.data,
230			     salt->saltvalue.length);
231	if (ret) {
232	    free_Key(&key);
233	    return ret;
234	}
235    } else
236	key.salt = NULL;
237
238    (*key_set)[*nkeyset] = key;
239
240    *nkeyset += 1;
241
242    return 0;
243}
244
245
246/*
247 * Generate the `key_set' from the [kadmin]default_keys statement. If
248 * `no_salt' is set, salt is not important (and will not be set) since
249 * it's random keys that is going to be created.
250 */
251
252krb5_error_code
253hdb_generate_key_set(krb5_context context, krb5_principal principal,
254		     Key **ret_key_set, size_t *nkeyset, int no_salt)
255{
256    char **ktypes, **kp;
257    krb5_error_code ret;
258    Key *k, *key_set;
259    size_t i, j;
260    static const char *default_keytypes[] = {
261	"aes256-cts-hmac-sha1-96:pw-salt",
262	"des3-cbc-sha1:pw-salt",
263	"arcfour-hmac-md5:pw-salt",
264	NULL
265    };
266
267    ktypes = krb5_config_get_strings(context, NULL, "kadmin",
268				     "default_keys", NULL);
269    if (ktypes == NULL)
270	ktypes = (char **)(intptr_t)default_keytypes;
271
272    *ret_key_set = key_set = NULL;
273    *nkeyset = 0;
274
275    ret = 0;
276
277    for(kp = ktypes; kp && *kp; kp++) {
278	const char *p;
279	krb5_salt salt;
280	krb5_enctype *enctypes;
281	size_t num_enctypes;
282
283	p = *kp;
284	/* check alias */
285	if(strcmp(p, "v5") == 0)
286	    p = "pw-salt";
287	else if(strcmp(p, "v4") == 0)
288	    p = "des:pw-salt:";
289	else if(strcmp(p, "afs") == 0 || strcmp(p, "afs3") == 0)
290	    p = "des:afs3-salt";
291	else if (strcmp(p, "arcfour-hmac-md5") == 0)
292	    p = "arcfour-hmac-md5:pw-salt";
293
294	memset(&salt, 0, sizeof(salt));
295
296	ret = parse_key_set(context, p,
297			    &enctypes, &num_enctypes, &salt, principal);
298	if (ret) {
299	    krb5_warn(context, ret, "bad value for default_keys `%s'", *kp);
300	    ret = 0;
301	    continue;
302	}
303
304	for (i = 0; i < num_enctypes; i++) {
305	    /* find duplicates */
306	    for (j = 0; j < *nkeyset; j++) {
307
308		k = &key_set[j];
309
310		if (k->key.keytype == enctypes[i]) {
311		    if (no_salt)
312			break;
313		    if (k->salt == NULL && salt.salttype == KRB5_PW_SALT)
314			break;
315		    if (k->salt->type == salt.salttype &&
316			k->salt->salt.length == salt.saltvalue.length &&
317			memcmp(k->salt->salt.data, salt.saltvalue.data,
318			       salt.saltvalue.length) == 0)
319			break;
320		}
321	    }
322	    /* not a duplicate, lets add it */
323	    if (j == *nkeyset) {
324		ret = add_enctype_to_key_set(&key_set, nkeyset, enctypes[i],
325					     no_salt ? NULL : &salt);
326		if (ret) {
327		    free(enctypes);
328		    krb5_free_salt(context, salt);
329		    goto out;
330		}
331	    }
332	}
333	free(enctypes);
334	krb5_free_salt(context, salt);
335    }
336
337    *ret_key_set = key_set;
338
339 out:
340    if (ktypes != (char **)(intptr_t)default_keytypes)
341	krb5_config_free_strings(ktypes);
342
343    if (ret) {
344	krb5_warn(context, ret,
345		  "failed to parse the [kadmin]default_keys values");
346
347	for (i = 0; i < *nkeyset; i++)
348	    free_Key(&key_set[i]);
349	free(key_set);
350    } else if (*nkeyset == 0) {
351	krb5_warnx(context,
352		   "failed to parse any of the [kadmin]default_keys values");
353	ret = EINVAL; /* XXX */
354    }
355
356    return ret;
357}
358
359
360krb5_error_code
361hdb_generate_key_set_password(krb5_context context,
362			      krb5_principal principal,
363			      const char *password,
364			      Key **keys, size_t *num_keys)
365{
366    krb5_error_code ret;
367    size_t i;
368
369    ret = hdb_generate_key_set(context, principal,
370				keys, num_keys, 0);
371    if (ret)
372	return ret;
373
374    for (i = 0; i < (*num_keys); i++) {
375	krb5_salt salt;
376
377	salt.salttype = (*keys)[i].salt->type;
378	salt.saltvalue.length = (*keys)[i].salt->salt.length;
379	salt.saltvalue.data = (*keys)[i].salt->salt.data;
380
381	ret = krb5_string_to_key_salt (context,
382				       (*keys)[i].key.keytype,
383				       password,
384				       salt,
385				       &(*keys)[i].key);
386
387	if(ret)
388	    break;
389    }
390
391    if(ret) {
392	hdb_free_keys (context, *num_keys, *keys);
393	return ret;
394    }
395    return ret;
396}
397