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