1 /*
2 * Copyright 1995-2023 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <limits.h>
11 #include <stdio.h>
12 #include "internal/cryptlib.h"
13 #include <openssl/asn1.h>
14 #include "asn1_local.h"
15
ASN1_BIT_STRING_set(ASN1_BIT_STRING * x,unsigned char * d,int len)16 int ASN1_BIT_STRING_set(ASN1_BIT_STRING *x, unsigned char *d, int len)
17 {
18 return ASN1_STRING_set(x, d, len);
19 }
20
ossl_i2c_ASN1_BIT_STRING(ASN1_BIT_STRING * a,unsigned char ** pp)21 int ossl_i2c_ASN1_BIT_STRING(ASN1_BIT_STRING *a, unsigned char **pp)
22 {
23 int ret, j, bits, len;
24 unsigned char *p, *d;
25
26 if (a == NULL)
27 return 0;
28
29 len = a->length;
30
31 if (len > 0) {
32 if (a->flags & ASN1_STRING_FLAG_BITS_LEFT) {
33 bits = (int)a->flags & 0x07;
34 } else {
35 for (; len > 0; len--) {
36 if (a->data[len - 1])
37 break;
38 }
39
40 if (len == 0) {
41 bits = 0;
42 } else {
43 j = a->data[len - 1];
44 if (j & 0x01)
45 bits = 0;
46 else if (j & 0x02)
47 bits = 1;
48 else if (j & 0x04)
49 bits = 2;
50 else if (j & 0x08)
51 bits = 3;
52 else if (j & 0x10)
53 bits = 4;
54 else if (j & 0x20)
55 bits = 5;
56 else if (j & 0x40)
57 bits = 6;
58 else if (j & 0x80)
59 bits = 7;
60 else
61 bits = 0; /* should not happen */
62 }
63 }
64 } else
65 bits = 0;
66
67 ret = 1 + len;
68 if (pp == NULL)
69 return ret;
70
71 p = *pp;
72
73 *(p++) = (unsigned char)bits;
74 d = a->data;
75 if (len > 0) {
76 memcpy(p, d, len);
77 p += len;
78 p[-1] &= (0xff << bits);
79 }
80 *pp = p;
81 return ret;
82 }
83
ossl_c2i_ASN1_BIT_STRING(ASN1_BIT_STRING ** a,const unsigned char ** pp,long len)84 ASN1_BIT_STRING *ossl_c2i_ASN1_BIT_STRING(ASN1_BIT_STRING **a,
85 const unsigned char **pp, long len)
86 {
87 ASN1_BIT_STRING *ret = NULL;
88 const unsigned char *p;
89 unsigned char *s;
90 int i = 0;
91
92 if (len < 1) {
93 i = ASN1_R_STRING_TOO_SHORT;
94 goto err;
95 }
96
97 if (len > INT_MAX) {
98 i = ASN1_R_STRING_TOO_LONG;
99 goto err;
100 }
101
102 if ((a == NULL) || ((*a) == NULL)) {
103 if ((ret = ASN1_BIT_STRING_new()) == NULL)
104 return NULL;
105 } else
106 ret = (*a);
107
108 p = *pp;
109 i = *(p++);
110 if (i > 7) {
111 i = ASN1_R_INVALID_BIT_STRING_BITS_LEFT;
112 goto err;
113 }
114 /*
115 * We do this to preserve the settings. If we modify the settings, via
116 * the _set_bit function, we will recalculate on output
117 */
118 ossl_asn1_string_set_bits_left(ret, i);
119
120 if (len-- > 1) { /* using one because of the bits left byte */
121 s = OPENSSL_malloc((int)len);
122 if (s == NULL) {
123 goto err;
124 }
125 memcpy(s, p, (int)len);
126 s[len - 1] &= (0xff << i);
127 p += len;
128 } else
129 s = NULL;
130
131 ASN1_STRING_set0(ret, s, (int)len);
132 ret->type = V_ASN1_BIT_STRING;
133 if (a != NULL)
134 (*a) = ret;
135 *pp = p;
136 return ret;
137 err:
138 if (i != 0)
139 ERR_raise(ERR_LIB_ASN1, i);
140 if ((a == NULL) || (*a != ret))
141 ASN1_BIT_STRING_free(ret);
142 return NULL;
143 }
144
145 /*
146 * These next 2 functions from Goetz Babin-Ebell.
147 */
ASN1_BIT_STRING_set_bit(ASN1_BIT_STRING * a,int n,int value)148 int ASN1_BIT_STRING_set_bit(ASN1_BIT_STRING *a, int n, int value)
149 {
150 int w, v, iv;
151 unsigned char *c;
152
153 if (n < 0)
154 return 0;
155
156 w = n / 8;
157 v = 1 << (7 - (n & 0x07));
158 iv = ~v;
159 if (!value)
160 v = 0;
161
162 if (a == NULL)
163 return 0;
164
165 a->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); /* clear, set on write */
166
167 if ((a->length < (w + 1)) || (a->data == NULL)) {
168 if (!value)
169 return 1; /* Don't need to set */
170 c = OPENSSL_clear_realloc(a->data, a->length, w + 1);
171 if (c == NULL)
172 return 0;
173 if (w + 1 - a->length > 0)
174 memset(c + a->length, 0, w + 1 - a->length);
175 a->data = c;
176 a->length = w + 1;
177 }
178 a->data[w] = ((a->data[w]) & iv) | v;
179 while ((a->length > 0) && (a->data[a->length - 1] == 0))
180 a->length--;
181 return 1;
182 }
183
ASN1_BIT_STRING_get_bit(const ASN1_BIT_STRING * a,int n)184 int ASN1_BIT_STRING_get_bit(const ASN1_BIT_STRING *a, int n)
185 {
186 int w, v;
187
188 if (n < 0)
189 return 0;
190
191 w = n / 8;
192 v = 1 << (7 - (n & 0x07));
193 if ((a == NULL) || (a->length < (w + 1)) || (a->data == NULL))
194 return 0;
195 return ((a->data[w] & v) != 0);
196 }
197
198 /*
199 * Checks if the given bit string contains only bits specified by
200 * the flags vector. Returns 0 if there is at least one bit set in 'a'
201 * which is not specified in 'flags', 1 otherwise.
202 * 'len' is the length of 'flags'.
203 */
ASN1_BIT_STRING_check(const ASN1_BIT_STRING * a,const unsigned char * flags,int flags_len)204 int ASN1_BIT_STRING_check(const ASN1_BIT_STRING *a,
205 const unsigned char *flags, int flags_len)
206 {
207 int i, ok;
208 /* Check if there is one bit set at all. */
209 if (!a || !a->data)
210 return 1;
211
212 /*
213 * Check each byte of the internal representation of the bit string.
214 */
215 ok = 1;
216 for (i = 0; i < a->length && ok; ++i) {
217 unsigned char mask = i < flags_len ? ~flags[i] : 0xff;
218 /* We are done if there is an unneeded bit set. */
219 ok = (a->data[i] & mask) == 0;
220 }
221 return ok;
222 }
223
