a_bitstr.c revision 4969cc9b0ab2905ec478277f50ed3849b37a6c6b 
1/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to.  The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 *    notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 *    notice, this list of conditions and the following disclaimer in the
29 *    documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 *    must display the following acknowledgement:
32 *    "This product includes cryptographic software written by
33 *     Eric Young (eay@cryptsoft.com)"
34 *    The word 'cryptographic' can be left out if the rouines from the library
35 *    being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 *    the apps directory (application code) you must include an acknowledgement:
38 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed.  i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.] */
56
57#include <openssl/asn1.h>
58
59#include <string.h>
60
61#include <openssl/err.h>
62#include <openssl/mem.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    memcpy(p, d, len);
119    p += len;
120    if (len > 0)
121        p[-1] &= (0xff << bits);
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 padding;
133
134    if (len < 1) {
135        OPENSSL_PUT_ERROR(ASN1, 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    padding = *(p++);
147    if (padding > 7) {
148        OPENSSL_PUT_ERROR(ASN1, ASN1_R_INVALID_BIT_STRING_BITS_LEFT);
149        goto err;
150    }
151
152    /*
153     * We do this to preserve the settings.  If we modify the settings, via
154     * the _set_bit function, we will recalculate on output
155     */
156    ret->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); /* clear */
157    ret->flags |= (ASN1_STRING_FLAG_BITS_LEFT | padding); /* set */
158
159    if (len-- > 1) {            /* using one because of the bits left byte */
160        s = (unsigned char *)OPENSSL_malloc((int)len);
161        if (s == NULL) {
162            OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
163            goto err;
164        }
165        memcpy(s, p, (int)len);
166        s[len - 1] &= (0xff << padding);
167        p += len;
168    } else
169        s = NULL;
170
171    ret->length = (int)len;
172    if (ret->data != NULL)
173        OPENSSL_free(ret->data);
174    ret->data = s;
175    ret->type = V_ASN1_BIT_STRING;
176    if (a != NULL)
177        (*a) = ret;
178    *pp = p;
179    return (ret);
180 err:
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            OPENSSL_PUT_ERROR(ASN1, 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