1/*
2 * Copyright 2000-2017 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 <stdio.h>
11#include "internal/cryptlib.h"
12#include <openssl/asn1t.h>
13
14#ifdef OPENSSL_NO_DEPRECATED_3_0
15NON_EMPTY_TRANSLATION_UNIT
16#else
17
18#define COPY_SIZE(a, b) (sizeof(a) < sizeof(b) ? sizeof(a) : sizeof(b))
19
20/*
21 * Custom primitive type for long handling. This converts between an
22 * ASN1_INTEGER and a long directly.
23 */
24
25static int long_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
26static void long_free(ASN1_VALUE **pval, const ASN1_ITEM *it);
27
28static int long_i2c(const ASN1_VALUE **pval, unsigned char *cont, int *putype,
29 const ASN1_ITEM *it);
30static int long_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
31 int utype, char *free_cont, const ASN1_ITEM *it);
32static int long_print(BIO *out, const ASN1_VALUE **pval, const ASN1_ITEM *it,
33 int indent, const ASN1_PCTX *pctx);
34
35static ASN1_PRIMITIVE_FUNCS long_pf = {
36 NULL, 0,
37 long_new,
38 long_free,
39 long_free, /* Clear should set to initial value */
40 long_c2i,
41 long_i2c,
42 long_print
43};
44
45ASN1_ITEM_start(LONG)
46 ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &long_pf, ASN1_LONG_UNDEF, "LONG"
47ASN1_ITEM_end(LONG)
48
49ASN1_ITEM_start(ZLONG)
50 ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &long_pf, 0, "ZLONG"
51ASN1_ITEM_end(ZLONG)
52
53static int long_new(ASN1_VALUE **pval, const ASN1_ITEM *it)
54{
55 memcpy(pval, &it->size, COPY_SIZE(*pval, it->size));
56 return 1;
57}
58
59static void long_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
60{
61 memcpy(pval, &it->size, COPY_SIZE(*pval, it->size));
62}
63
64/*
65 * Originally BN_num_bits_word was called to perform this operation, but
66 * trouble is that there is no guarantee that sizeof(long) equals to
67 * sizeof(BN_ULONG). BN_ULONG is a configurable type that can be as wide
68 * as long, but also double or half...
69 */
70static int num_bits_ulong(unsigned long value)
71{
72 size_t i;
73 unsigned long ret = 0;
74
75 /*
76 * It is argued that *on average* constant counter loop performs
77 * not worse [if not better] than one with conditional break or
78 * mask-n-table-lookup-style, because of branch misprediction
79 * penalties.
80 */
81 for (i = 0; i < sizeof(value) * 8; i++) {
82 ret += (value != 0);
83 value >>= 1;
84 }
85
86 return (int)ret;
87}
88
89static int long_i2c(const ASN1_VALUE **pval, unsigned char *cont, int *putype,
90 const ASN1_ITEM *it)
91{
92 long ltmp;
93 unsigned long utmp, sign;
94 int clen, pad, i;
95
96 memcpy(&ltmp, pval, COPY_SIZE(*pval, ltmp));
97 if (ltmp == it->size)
98 return -1;
99 /*
100 * Convert the long to positive: we subtract one if negative so we can
101 * cleanly handle the padding if only the MSB of the leading octet is
102 * set.
103 */
104 if (ltmp < 0) {
105 sign = 0xff;
106 utmp = 0 - (unsigned long)ltmp - 1;
107 } else {
108 sign = 0;
109 utmp = ltmp;
110 }
111 clen = num_bits_ulong(utmp);
112 /* If MSB of leading octet set we need to pad */
113 if (!(clen & 0x7))
114 pad = 1;
115 else
116 pad = 0;
117
118 /* Convert number of bits to number of octets */
119 clen = (clen + 7) >> 3;
120
121 if (cont != NULL) {
122 if (pad)
123 *cont++ = (unsigned char)sign;
124 for (i = clen - 1; i >= 0; i--) {
125 cont[i] = (unsigned char)(utmp ^ sign);
126 utmp >>= 8;
127 }
128 }
129 return clen + pad;
130}
131
132static int long_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
133 int utype, char *free_cont, const ASN1_ITEM *it)
134{
135 int i;
136 long ltmp;
137 unsigned long utmp = 0, sign = 0x100;
138
139 if (len > 1) {
140 /*
141 * Check possible pad byte. Worst case, we're skipping past actual
142 * content, but since that's only with 0x00 and 0xff and we set neg
143 * accordingly, the result will be correct in the end anyway.
144 */
145 switch (cont[0]) {
146 case 0xff:
147 cont++;
148 len--;
149 sign = 0xff;
150 break;
151 case 0:
152 cont++;
153 len--;
154 sign = 0;
155 break;
156 }
157 }
158 if (len > (int)sizeof(long)) {
159 ASN1err(ASN1_F_LONG_C2I, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG);
160 return 0;
161 }
162
163 if (sign == 0x100) {
164 /* Is it negative? */
165 if (len && (cont[0] & 0x80))
166 sign = 0xff;
167 else
168 sign = 0;
169 } else if (((sign ^ cont[0]) & 0x80) == 0) { /* same sign bit? */
170 ASN1err(ASN1_F_LONG_C2I, ASN1_R_ILLEGAL_PADDING);
171 return 0;
172 }
173 utmp = 0;
174 for (i = 0; i < len; i++) {
175 utmp <<= 8;
176 utmp |= cont[i] ^ sign;
177 }
178 ltmp = (long)utmp;
179 if (ltmp < 0) {
180 ASN1err(ASN1_F_LONG_C2I, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG);
181 return 0;
182 }
183 if (sign)
184 ltmp = -ltmp - 1;
185 if (ltmp == it->size) {
186 ASN1err(ASN1_F_LONG_C2I, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG);
187 return 0;
188 }
189 memcpy(pval, &ltmp, COPY_SIZE(*pval, ltmp));
190 return 1;
191}
192
193static int long_print(BIO *out, const ASN1_VALUE **pval, const ASN1_ITEM *it,
194 int indent, const ASN1_PCTX *pctx)
195{
196 long l;
197
198 memcpy(&l, pval, COPY_SIZE(*pval, l));
199 return BIO_printf(out, "%ld\n", l);
200}
201#endif
202