a_bitstr.c revision 325337 
1/* crypto/asn1/a_bitstr.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to.  The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 *    notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 *    notice, this list of conditions and the following disclaimer in the
30 *    documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 *    must display the following acknowledgement:
33 *    "This product includes cryptographic software written by
34 *     Eric Young (eay@cryptsoft.com)"
35 *    The word 'cryptographic' can be left out if the rouines from the library
36 *    being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 *    the apps directory (application code) you must include an acknowledgement:
39 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed.  i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59#include <limits.h>
60#include <stdio.h>
61#include "cryptlib.h"
62#include <openssl/asn1.h>
63
64int ASN1_BIT_STRING_set(ASN1_BIT_STRING *x, unsigned char *d, int len)
65{
66    return M_ASN1_BIT_STRING_set(x, d, len);
67}
68
69int i2c_ASN1_BIT_STRING(ASN1_BIT_STRING *a, unsigned char **pp)
70{
71    int ret, j, bits, len;
72    unsigned char *p, *d;
73
74    if (a == NULL)
75        return (0);
76
77    len = a->length;
78
79    if (len > 0) {
80        if (a->flags & ASN1_STRING_FLAG_BITS_LEFT) {
81            bits = (int)a->flags & 0x07;
82        } else {
83            for (; len > 0; len--) {
84                if (a->data[len - 1])
85                    break;
86            }
87            j = a->data[len - 1];
88            if (j & 0x01)
89                bits = 0;
90            else if (j & 0x02)
91                bits = 1;
92            else if (j & 0x04)
93                bits = 2;
94            else if (j & 0x08)
95                bits = 3;
96            else if (j & 0x10)
97                bits = 4;
98            else if (j & 0x20)
99                bits = 5;
100            else if (j & 0x40)
101                bits = 6;
102            else if (j & 0x80)
103                bits = 7;
104            else
105                bits = 0;       /* should not happen */
106        }
107    } else
108        bits = 0;
109
110    ret = 1 + len;
111    if (pp == NULL)
112        return (ret);
113
114    p = *pp;
115
116    *(p++) = (unsigned char)bits;
117    d = a->data;
118    if (len > 0) {
119        memcpy(p, d, len);
120        p += len;
121        p[-1] &= (0xff << bits);
122    }
123    *pp = p;
124    return (ret);
125}
126
127ASN1_BIT_STRING *c2i_ASN1_BIT_STRING(ASN1_BIT_STRING **a,
128                                     const unsigned char **pp, long len)
129{
130    ASN1_BIT_STRING *ret = NULL;
131    const unsigned char *p;
132    unsigned char *s;
133    int i;
134
135    if (len < 1) {
136        i = ASN1_R_STRING_TOO_SHORT;
137        goto err;
138    }
139
140    if (len > INT_MAX) {
141        i = ASN1_R_STRING_TOO_LONG;
142        goto err;
143    }
144
145    if ((a == NULL) || ((*a) == NULL)) {
146        if ((ret = M_ASN1_BIT_STRING_new()) == NULL)
147            return (NULL);
148    } else
149        ret = (*a);
150
151    p = *pp;
152    i = *(p++);
153    if (i > 7) {
154        i = ASN1_R_INVALID_BIT_STRING_BITS_LEFT;
155        goto err;
156    }
157    /*
158     * We do this to preserve the settings.  If we modify the settings, via
159     * the _set_bit function, we will recalculate on output
160     */
161    ret->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); /* clear */
162    ret->flags |= (ASN1_STRING_FLAG_BITS_LEFT | i); /* set */
163
164    if (len-- > 1) {            /* using one because of the bits left byte */
165        s = (unsigned char *)OPENSSL_malloc((int)len);
166        if (s == NULL) {
167            i = ERR_R_MALLOC_FAILURE;
168            goto err;
169        }
170        memcpy(s, p, (int)len);
171        s[len - 1] &= (0xff << i);
172        p += len;
173    } else
174        s = NULL;
175
176    ret->length = (int)len;
177    if (ret->data != NULL)
178        OPENSSL_free(ret->data);
179    ret->data = s;
180    ret->type = V_ASN1_BIT_STRING;
181    if (a != NULL)
182        (*a) = ret;
183    *pp = p;
184    return (ret);
185 err:
186    ASN1err(ASN1_F_C2I_ASN1_BIT_STRING, i);
187    if ((ret != NULL) && ((a == NULL) || (*a != ret)))
188        M_ASN1_BIT_STRING_free(ret);
189    return (NULL);
190}
191
192/*
193 * These next 2 functions from Goetz Babin-Ebell <babinebell@trustcenter.de>
194 */
195int ASN1_BIT_STRING_set_bit(ASN1_BIT_STRING *a, int n, int value)
196{
197    int w, v, iv;
198    unsigned char *c;
199
200    w = n / 8;
201    v = 1 << (7 - (n & 0x07));
202    iv = ~v;
203    if (!value)
204        v = 0;
205
206    if (a == NULL)
207        return 0;
208
209    a->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); /* clear, set on write */
210
211    if ((a->length < (w + 1)) || (a->data == NULL)) {
212        if (!value)
213            return (1);         /* Don't need to set */
214        if (a->data == NULL)
215            c = (unsigned char *)OPENSSL_malloc(w + 1);
216        else
217            c = (unsigned char *)OPENSSL_realloc_clean(a->data,
218                                                       a->length, w + 1);
219        if (c == NULL) {
220            ASN1err(ASN1_F_ASN1_BIT_STRING_SET_BIT, ERR_R_MALLOC_FAILURE);
221            return 0;
222        }
223        if (w + 1 - a->length > 0)
224            memset(c + a->length, 0, w + 1 - a->length);
225        a->data = c;
226        a->length = w + 1;
227    }
228    a->data[w] = ((a->data[w]) & iv) | v;
229    while ((a->length > 0) && (a->data[a->length - 1] == 0))
230        a->length--;
231    return (1);
232}
233
234int ASN1_BIT_STRING_get_bit(ASN1_BIT_STRING *a, int n)
235{
236    int w, v;
237
238    w = n / 8;
239    v = 1 << (7 - (n & 0x07));
240    if ((a == NULL) || (a->length < (w + 1)) || (a->data == NULL))
241        return (0);
242    return ((a->data[w] & v) != 0);
243}
244
245/*
246 * Checks if the given bit string contains only bits specified by
247 * the flags vector. Returns 0 if there is at least one bit set in 'a'
248 * which is not specified in 'flags', 1 otherwise.
249 * 'len' is the length of 'flags'.
250 */
251int ASN1_BIT_STRING_check(ASN1_BIT_STRING *a,
252                          unsigned char *flags, int flags_len)
253{
254    int i, ok;
255    /* Check if there is one bit set at all. */
256    if (!a || !a->data)
257        return 1;
258
259    /*
260     * Check each byte of the internal representation of the bit string.
261     */
262    ok = 1;
263    for (i = 0; i < a->length && ok; ++i) {
264        unsigned char mask = i < flags_len ? ~flags[i] : 0xff;
265        /* We are done if there is an unneeded bit set. */
266        ok = (a->data[i] & mask) == 0;
267    }
268    return ok;
269}
270