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-rw-r--r--src/lib/libcrypto/asn1/asn1_lib.c204
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diff --git a/src/lib/libcrypto/asn1/asn1_lib.c b/src/lib/libcrypto/asn1/asn1_lib.c
deleted file mode 100644
index ac8da0e61d..0000000000
--- a/src/lib/libcrypto/asn1/asn1_lib.c
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1/* $OpenBSD: asn1_lib.c,v 1.54 2022/05/05 19:18:56 jsing Exp $ */
2/*
3 * Copyright (c) 2021 Joel Sing <jsing@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <limits.h>
19#include <stdlib.h>
20
21#include "bytestring.h"
22
23int
24asn1_get_identifier_cbs(CBS *cbs, int der_mode, uint8_t *out_class,
25 int *out_constructed, uint32_t *out_tag_number)
26{
27 uint8_t tag_class, tag_val;
28 int tag_constructed;
29 uint32_t tag_number;
30
31 /*
32 * Decode ASN.1 identifier octets - see ITU-T X.690 section 8.1.2.
33 */
34
35 *out_class = 0;
36 *out_constructed = 0;
37 *out_tag_number = 0;
38
39 if (!CBS_get_u8(cbs, &tag_val))
40 return 0;
41
42 /*
43 * ASN.1 tag class, encoding (primitive or constructed) and tag number
44 * are encoded in one or more identifier octets - the first octet
45 * contains the 2 bit tag class, the 1 bit encoding type and 5 bits
46 * of tag number.
47 *
48 * For tag numbers larger than 30 (0x1e) the 5 bit tag number in the
49 * first octet is set to all ones (0x1f) - the tag number is then
50 * encoded in subsequent octets - each of which have a one bit
51 * continuation flag and 7 bits of tag number in big-endian form.
52 * The encoding should not contain leading zeros but can for BER.
53 */
54 tag_class = (tag_val >> 6) & 0x3;
55 tag_constructed = (tag_val >> 5) & 0x1;
56 tag_number = tag_val & 0x1f;
57
58 /* Long form. */
59 if (tag_number == 0x1f) {
60 tag_number = 0;
61 do {
62 if (!CBS_get_u8(cbs, &tag_val))
63 return 0;
64 if (der_mode && tag_number == 0 && tag_val == 0x80)
65 return 0;
66 if (tag_number > (UINT32_MAX >> 7))
67 return 0;
68 tag_number = tag_number << 7 | (tag_val & 0x7f);
69 } while ((tag_val & 0x80) != 0);
70 }
71
72 *out_class = tag_class;
73 *out_constructed = tag_constructed;
74 *out_tag_number = tag_number;
75
76 return 1;
77}
78
79int
80asn1_get_length_cbs(CBS *cbs, int der_mode, int *out_indefinite,
81 size_t *out_length)
82{
83 uint8_t len_bytes;
84 size_t length;
85 uint8_t val;
86
87 /*
88 * Decode ASN.1 length octets - see ITU-T X.690 section 8.1.3.
89 */
90
91 *out_length = 0;
92 *out_indefinite = 0;
93
94 if (!CBS_get_u8(cbs, &val))
95 return 0;
96
97 /*
98 * Short form - length is encoded in the lower 7 bits of a single byte.
99 */
100 if (val < 0x80) {
101 *out_length = val;
102 return 1;
103 }
104
105 /*
106 * Indefinite length - content continues until an End of Content (EOC)
107 * marker is reached. Must be used with constructed encoding.
108 */
109 if (val == 0x80) {
110 *out_indefinite = 1;
111 return 1;
112 }
113
114 /*
115 * Long form - the lower 7 bits of the first byte specifies the number
116 * of bytes used to encode the length, the following bytes specify the
117 * length in big-endian form. The encoding should not contain leading
118 * zeros but can for BER. A length value of 0x7f is invalid.
119 */
120 if ((len_bytes = val & 0x7f) == 0x7f)
121 return 0;
122
123 length = 0;
124
125 while (len_bytes-- > 0) {
126 if (!CBS_get_u8(cbs, &val))
127 return 0;
128 if (der_mode && length == 0 && val == 0)
129 return 0;
130 if (length > (SIZE_MAX >> 8))
131 return 0;
132 length = (length << 8) | val;
133 }
134
135 *out_length = length;
136
137 return 1;
138}
139
140int
141asn1_get_object_cbs(CBS *cbs, int der_mode, uint8_t *out_tag_class,
142 int *out_constructed, uint32_t *out_tag_number, int *out_indefinite,
143 size_t *out_length)
144{
145 int constructed, indefinite;
146 uint32_t tag_number;
147 uint8_t tag_class;
148 size_t length;
149
150 *out_tag_class = 0;
151 *out_constructed = 0;
152 *out_tag_number = 0;
153 *out_indefinite = 0;
154 *out_length = 0;
155
156 if (!asn1_get_identifier_cbs(cbs, der_mode, &tag_class, &constructed,
157 &tag_number))
158 return 0;
159 if (!asn1_get_length_cbs(cbs, der_mode, &indefinite, &length))
160 return 0;
161
162 /* Indefinite length can only be used with constructed encoding. */
163 if (indefinite && !constructed)
164 return 0;
165
166 *out_tag_class = tag_class;
167 *out_constructed = constructed;
168 *out_tag_number = tag_number;
169 *out_indefinite = indefinite;
170 *out_length = length;
171
172 return 1;
173}
174
175int
176asn1_get_primitive(CBS *cbs, int der_mode, uint32_t *out_tag_number,
177 CBS *out_content)
178{
179 int constructed, indefinite;
180 uint32_t tag_number;
181 uint8_t tag_class;
182 size_t length;
183
184 *out_tag_number = 0;
185
186 CBS_init(out_content, NULL, 0);
187
188 if (!asn1_get_identifier_cbs(cbs, der_mode, &tag_class, &constructed,
189 &tag_number))
190 return 0;
191 if (!asn1_get_length_cbs(cbs, der_mode, &indefinite, &length))
192 return 0;
193
194 /* A primitive is not constructed and has a definite length. */
195 if (constructed || indefinite)
196 return 0;
197
198 if (!CBS_get_bytes(cbs, out_content, length))
199 return 0;
200
201 *out_tag_number = tag_number;
202
203 return 1;
204}
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