a_bitstr.c revision 325335 
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 <stdio.h>
60#include "cryptlib.h"
61#include <openssl/asn1.h>
62
63int ASN1_BIT_STRING_set(ASN1_BIT_STRING *x, unsigned char *d, int len)
64{
65    return M_ASN1_BIT_STRING_set(x, d, len);
66}
67
68int i2c_ASN1_BIT_STRING(ASN1_BIT_STRING *a, unsigned char **pp)
69{
70    int ret, j, bits, len;
71    unsigned char *p, *d;
72
73    if (a == NULL)
74        return (0);
75
76    len = a->length;
77
78    if (len > 0) {
79        if (a->flags & ASN1_STRING_FLAG_BITS_LEFT) {
80            bits = (int)a->flags & 0x07;
81        } else {
82            for (; len > 0; len--) {
83                if (a->data[len - 1])
84                    break;
85            }
86            j = a->data[len - 1];
87            if (j & 0x01)
88                bits = 0;
89            else if (j & 0x02)
90                bits = 1;
91            else if (j & 0x04)
92                bits = 2;
93            else if (j & 0x08)
94                bits = 3;
95            else if (j & 0x10)
96                bits = 4;
97            else if (j & 0x20)
98                bits = 5;
99            else if (j & 0x40)
100                bits = 6;
101            else if (j & 0x80)
102                bits = 7;
103            else
104                bits = 0;       /* should not happen */
105        }
106    } else
107        bits = 0;
108
109    ret = 1 + len;
110    if (pp == NULL)
111        return (ret);
112
113    p = *pp;
114
115    *(p++) = (unsigned char)bits;
116    d = a->data;
117    if (len > 0) {
118        memcpy(p, d, len);
119        p += len;
120        p[-1] &= (0xff << bits);
121    }
122    *pp = p;
123    return (ret);
124}
125
126ASN1_BIT_STRING *c2i_ASN1_BIT_STRING(ASN1_BIT_STRING **a,
127                                     const unsigned char **pp, long len)
128{
129    ASN1_BIT_STRING *ret = NULL;
130    const unsigned char *p;
131    unsigned char *s;
132    int i;
133
134    if (len < 1) {
135        i = ASN1_R_STRING_TOO_SHORT;
136        goto err;
137    }
138
139    if ((a == NULL) || ((*a) == NULL)) {
140        if ((ret = M_ASN1_BIT_STRING_new()) == NULL)
141            return (NULL);
142    } else
143        ret = (*a);
144
145    p = *pp;
146    i = *(p++);
147    if (i > 7) {
148        i = ASN1_R_INVALID_BIT_STRING_BITS_LEFT;
149        goto err;
150    }
151    /*
152     * We do this to preserve the settings.  If we modify the settings, via
153     * the _set_bit function, we will recalculate on output
154     */
155    ret->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); /* clear */
156    ret->flags |= (ASN1_STRING_FLAG_BITS_LEFT | i); /* set */
157
158    if (len-- > 1) {            /* using one because of the bits left byte */
159        s = (unsigned char *)OPENSSL_malloc((int)len);
160        if (s == NULL) {
161            i = ERR_R_MALLOC_FAILURE;
162            goto err;
163        }
164        memcpy(s, p, (int)len);
165        s[len - 1] &= (0xff << i);
166        p += len;
167    } else
168        s = NULL;
169
170    ret->length = (int)len;
171    if (ret->data != NULL)
172        OPENSSL_free(ret->data);
173    ret->data = s;
174    ret->type = V_ASN1_BIT_STRING;
175    if (a != NULL)
176        (*a) = ret;
177    *pp = p;
178    return (ret);
179 err:
180    ASN1err(ASN1_F_C2I_ASN1_BIT_STRING, i);
181    if ((ret != NULL) && ((a == NULL) || (*a != ret)))
182        M_ASN1_BIT_STRING_free(ret);
183    return (NULL);
184}
185
186/*
187 * These next 2 functions from Goetz Babin-Ebell <babinebell@trustcenter.de>
188 */
189int ASN1_BIT_STRING_set_bit(ASN1_BIT_STRING *a, int n, int value)
190{
191    int w, v, iv;
192    unsigned char *c;
193
194    w = n / 8;
195    v = 1 << (7 - (n & 0x07));
196    iv = ~v;
197    if (!value)
198        v = 0;
199
200    if (a == NULL)
201        return 0;
202
203    a->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); /* clear, set on write */
204
205    if ((a->length < (w + 1)) || (a->data == NULL)) {
206        if (!value)
207            return (1);         /* Don't need to set */
208        if (a->data == NULL)
209            c = (unsigned char *)OPENSSL_malloc(w + 1);
210        else
211            c = (unsigned char *)OPENSSL_realloc_clean(a->data,
212                                                       a->length, w + 1);
213        if (c == NULL) {
214            ASN1err(ASN1_F_ASN1_BIT_STRING_SET_BIT, ERR_R_MALLOC_FAILURE);
215            return 0;
216        }
217        if (w + 1 - a->length > 0)
218            memset(c + a->length, 0, w + 1 - a->length);
219        a->data = c;
220        a->length = w + 1;
221    }
222    a->data[w] = ((a->data[w]) & iv) | v;
223    while ((a->length > 0) && (a->data[a->length - 1] == 0))
224        a->length--;
225    return (1);
226}
227
228int ASN1_BIT_STRING_get_bit(ASN1_BIT_STRING *a, int n)
229{
230    int w, v;
231
232    w = n / 8;
233    v = 1 << (7 - (n & 0x07));
234    if ((a == NULL) || (a->length < (w + 1)) || (a->data == NULL))
235        return (0);
236    return ((a->data[w] & v) != 0);
237}
238
239/*
240 * Checks if the given bit string contains only bits specified by
241 * the flags vector. Returns 0 if there is at least one bit set in 'a'
242 * which is not specified in 'flags', 1 otherwise.
243 * 'len' is the length of 'flags'.
244 */
245int ASN1_BIT_STRING_check(ASN1_BIT_STRING *a,
246                          unsigned char *flags, int flags_len)
247{
248    int i, ok;
249    /* Check if there is one bit set at all. */
250    if (!a || !a->data)
251        return 1;
252
253    /*
254     * Check each byte of the internal representation of the bit string.
255     */
256    ok = 1;
257    for (i = 0; i < a->length && ok; ++i) {
258        unsigned char mask = i < flags_len ? ~flags[i] : 0xff;
259        /* We are done if there is an unneeded bit set. */
260        ok = (a->data[i] & mask) == 0;
261    }
262    return ok;
263}
264