1 /* $OpenBSD: tasn_utl.c,v 1.17 2022/05/12 19:55:58 jsing Exp $ */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3  * project 2000.
4  */
5 /* ====================================================================
6  * Copyright (c) 2000-2004 The OpenSSL Project.  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
17  *    the documentation and/or other materials provided with the
18  *    distribution.
19  *
20  * 3. All advertising materials mentioning features or use of this
21  *    software must display the following acknowledgment:
22  *    "This product includes software developed by the OpenSSL Project
23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24  *
25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26  *    endorse or promote products derived from this software without
27  *    prior written permission. For written permission, please contact
28  *    licensing@OpenSSL.org.
29  *
30  * 5. Products derived from this software may not be called "OpenSSL"
31  *    nor may "OpenSSL" appear in their names without prior written
32  *    permission of the OpenSSL Project.
33  *
34  * 6. Redistributions of any form whatsoever must retain the following
35  *    acknowledgment:
36  *    "This product includes software developed by the OpenSSL Project
37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38  *
39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50  * OF THE POSSIBILITY OF SUCH DAMAGE.
51  * ====================================================================
52  *
53  * This product includes cryptographic software written by Eric Young
54  * (eay@cryptsoft.com).  This product includes software written by Tim
55  * Hudson (tjh@cryptsoft.com).
56  *
57  */
58 
59 #include <limits.h>
60 #include <stddef.h>
61 #include <string.h>
62 
63 #include <openssl/asn1.h>
64 #include <openssl/asn1t.h>
65 #include <openssl/objects.h>
66 #include <openssl/err.h>
67 
68 #include "bytestring.h"
69 
70 /* Utility functions for manipulating fields and offsets */
71 
72 /* Add 'offset' to 'addr' */
73 #define offset2ptr(addr, offset) (void *)(((char *) addr) + offset)
74 
75 /* Given an ASN1_ITEM CHOICE type return
76  * the selector value
77  */
78 
79 int
80 asn1_get_choice_selector(ASN1_VALUE **pval, const ASN1_ITEM *it)
81 {
82 	int *sel = offset2ptr(*pval, it->utype);
83 	return *sel;
84 }
85 
86 /* Given an ASN1_ITEM CHOICE type set
87  * the selector value, return old value.
88  */
89 
90 int
91 asn1_set_choice_selector(ASN1_VALUE **pval, int value, const ASN1_ITEM *it)
92 {
93 	int *sel, ret;
94 	sel = offset2ptr(*pval, it->utype);
95 	ret = *sel;
96 	*sel = value;
97 	return ret;
98 }
99 
100 /* Do reference counting. The value 'op' decides what to do.
101  * if it is +1 then the count is incremented. If op is 0 count is
102  * set to 1. If op is -1 count is decremented and the return value
103  * is the current refrence count or 0 if no reference count exists.
104  */
105 
106 int
107 asn1_do_lock(ASN1_VALUE **pval, int op, const ASN1_ITEM *it)
108 {
109 	const ASN1_AUX *aux;
110 	int *lck, ret;
111 
112 	if ((it->itype != ASN1_ITYPE_SEQUENCE) &&
113 	    (it->itype != ASN1_ITYPE_NDEF_SEQUENCE))
114 		return 0;
115 	aux = it->funcs;
116 	if (!aux || !(aux->flags & ASN1_AFLG_REFCOUNT))
117 		return 0;
118 	lck = offset2ptr(*pval, aux->ref_offset);
119 	if (op == 0) {
120 		*lck = 1;
121 		return 1;
122 	}
123 	ret = CRYPTO_add(lck, op, aux->ref_lock);
124 	return ret;
125 }
126 
127 static ASN1_ENCODING *
128 asn1_get_enc_ptr(ASN1_VALUE **pval, const ASN1_ITEM *it)
129 {
130 	const ASN1_AUX *aux = it->funcs;
131 
132 	if (pval == NULL || *pval == NULL)
133 		return NULL;
134 
135 	if (aux == NULL || (aux->flags & ASN1_AFLG_ENCODING) == 0)
136 		return NULL;
137 
138 	return offset2ptr(*pval, aux->enc_offset);
139 }
140 
141 void
142 asn1_enc_init(ASN1_VALUE **pval, const ASN1_ITEM *it)
143 {
144 	ASN1_ENCODING *aenc;
145 
146 	if ((aenc = asn1_get_enc_ptr(pval, it)) == NULL)
147 		return;
148 
149 	aenc->enc = NULL;
150 	aenc->len = 0;
151 	aenc->modified = 1;
152 }
153 
154 static void
155 asn1_enc_clear(ASN1_ENCODING *aenc)
156 {
157 	freezero(aenc->enc, aenc->len);
158 	aenc->enc = NULL;
159 	aenc->len = 0;
160 	aenc->modified = 1;
161 }
162 
163 void
164 asn1_enc_cleanup(ASN1_VALUE **pval, const ASN1_ITEM *it)
165 {
166 	ASN1_ENCODING *aenc;
167 
168 	if ((aenc = asn1_get_enc_ptr(pval, it)) == NULL)
169 		return;
170 
171 	asn1_enc_clear(aenc);
172 }
173 
174 int
175 asn1_enc_save(ASN1_VALUE **pval, CBS *cbs, const ASN1_ITEM *it)
176 {
177 	ASN1_ENCODING *aenc;
178 	uint8_t *data = NULL;
179 	size_t data_len = 0;
180 
181 	if ((aenc = asn1_get_enc_ptr(pval, it)) == NULL)
182 		return 1;
183 
184 	asn1_enc_clear(aenc);
185 
186 	if (!CBS_stow(cbs, &data, &data_len))
187 		return 0;
188 	if (data_len > LONG_MAX) {
189 		freezero(data, data_len);
190 		return 0;
191 	}
192 
193 	aenc->enc = data;
194 	aenc->len = (long)data_len;
195 	aenc->modified = 0;
196 
197 	return 1;
198 }
199 
200 int
201 asn1_enc_restore(int *out_len, unsigned char **out, ASN1_VALUE **pval,
202     const ASN1_ITEM *it)
203 {
204 	ASN1_ENCODING *aenc;
205 
206 	if ((aenc = asn1_get_enc_ptr(pval, it)) == NULL)
207 		return 0;
208 
209 	if (aenc->modified)
210 		return 0;
211 
212 	if (out != NULL) {
213 		memcpy(*out, aenc->enc, aenc->len);
214 		*out += aenc->len;
215 	}
216 
217 	if (out_len != NULL)
218 		*out_len = aenc->len;
219 
220 	return 1;
221 }
222 
223 /* Given an ASN1_TEMPLATE get a pointer to a field */
224 ASN1_VALUE **
225 asn1_get_field_ptr(ASN1_VALUE **pval, const ASN1_TEMPLATE *tt)
226 {
227 	ASN1_VALUE **pvaltmp;
228 
229 	pvaltmp = offset2ptr(*pval, tt->offset);
230 	/* NOTE for BOOLEAN types the field is just a plain
231  	 * int so we can't return int **, so settle for
232 	 * (int *).
233 	 */
234 	return pvaltmp;
235 }
236 
237 /* Handle ANY DEFINED BY template, find the selector, look up
238  * the relevant ASN1_TEMPLATE in the table and return it.
239  */
240 
241 const ASN1_TEMPLATE *
242 asn1_do_adb(ASN1_VALUE **pval, const ASN1_TEMPLATE *tt, int nullerr)
243 {
244 	const ASN1_ADB *adb;
245 	const ASN1_ADB_TABLE *atbl;
246 	long selector;
247 	ASN1_VALUE **sfld;
248 	int i;
249 
250 	if (!(tt->flags & ASN1_TFLG_ADB_MASK))
251 		return tt;
252 
253 	/* Else ANY DEFINED BY ... get the table */
254 	adb = (const ASN1_ADB *)tt->item;
255 
256 	/* Get the selector field */
257 	sfld = offset2ptr(*pval, adb->offset);
258 
259 	/* Check if NULL */
260 	if (!sfld) {
261 		if (!adb->null_tt)
262 			goto err;
263 		return adb->null_tt;
264 	}
265 
266 	/* Convert type to a long:
267 	 * NB: don't check for NID_undef here because it
268 	 * might be a legitimate value in the table
269 	 */
270 	if (tt->flags & ASN1_TFLG_ADB_OID)
271 		selector = OBJ_obj2nid((ASN1_OBJECT *)*sfld);
272 	else
273 		selector = ASN1_INTEGER_get((ASN1_INTEGER *)*sfld);
274 
275 	/* Try to find matching entry in table
276 	 * Maybe should check application types first to
277 	 * allow application override? Might also be useful
278 	 * to have a flag which indicates table is sorted and
279 	 * we can do a binary search. For now stick to a
280 	 * linear search.
281 	 */
282 
283 	for (atbl = adb->tbl, i = 0; i < adb->tblcount; i++, atbl++)
284 		if (atbl->value == selector)
285 			return &atbl->tt;
286 
287 	/* FIXME: need to search application table too */
288 
289 	/* No match, return default type */
290 	if (!adb->default_tt)
291 		goto err;
292 	return adb->default_tt;
293 
294  err:
295 	/* FIXME: should log the value or OID of unsupported type */
296 	if (nullerr)
297 		ASN1error(ASN1_R_UNSUPPORTED_ANY_DEFINED_BY_TYPE);
298 	return NULL;
299 }
300