1 /* $OpenBSD: bn_print.c,v 1.47 2024/03/02 09:18:28 tb Exp $ */
2
3 /*
4 * Copyright (c) 2023 Theo Buehler <tb@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <ctype.h>
20 #include <stdarg.h>
21 #include <stdio.h>
22 #include <stdint.h>
23 #include <stdlib.h>
24
25 #include <openssl/bio.h>
26 #include <openssl/bn.h>
27
28 #include "bio_local.h"
29 #include "bn_local.h"
30 #include "bytestring.h"
31
32 static int
bn_print_zero(BIO * bio,const BIGNUM * bn)33 bn_print_zero(BIO *bio, const BIGNUM *bn)
34 {
35 if (!BN_is_zero(bn))
36 return 0;
37 if (BIO_printf(bio, " 0\n") <= 0)
38 return 0;
39 return 1;
40 }
41
42 static int
bn_print_word(BIO * bio,const BIGNUM * bn)43 bn_print_word(BIO *bio, const BIGNUM *bn)
44 {
45 unsigned long long word;
46 const char *neg = "";
47
48 if (BN_is_zero(bn) || BN_num_bytes(bn) > BN_BYTES)
49 return 0;
50
51 if (BN_is_negative(bn))
52 neg = "-";
53
54 word = BN_get_word(bn);
55 if (BIO_printf(bio, " %s%llu (%s0x%llx)\n", neg, word, neg, word) <= 0)
56 return 0;
57
58 return 1;
59 }
60
61 static int
bn_print_bignum(BIO * bio,const BIGNUM * bn,int indent)62 bn_print_bignum(BIO *bio, const BIGNUM *bn, int indent)
63 {
64 CBS cbs;
65 char *hex = NULL;
66 size_t hex_len = 0;
67 size_t octets = 0;
68 uint8_t hi, lo;
69 const char *sep = ":";
70 int ret = 0;
71
72 if (BN_num_bytes(bn) <= BN_BYTES)
73 goto err;
74
75 /* Secondary indent is 4 spaces, capped at 128. */
76 if (indent > 124)
77 indent = 124;
78 indent += 4;
79 if (indent < 0)
80 indent = 0;
81
82 if (!bn_bn2hex_nosign(bn, &hex, &hex_len))
83 goto err;
84
85 CBS_init(&cbs, hex, hex_len);
86
87 if (BN_is_negative(bn)) {
88 if (BIO_printf(bio, " (Negative)") <= 0)
89 goto err;
90 }
91
92 while (CBS_len(&cbs) > 0) {
93 if (!CBS_get_u8(&cbs, &hi))
94 goto err;
95 if (!CBS_get_u8(&cbs, &lo))
96 goto err;
97 if (octets++ % 15 == 0) {
98 if (BIO_printf(bio, "\n%*s", indent, "") <= 0)
99 goto err;
100 }
101 /* First nibble has the high bit set. Insert leading 0 octet. */
102 if (octets == 1 && hi >= '8') {
103 if (BIO_printf(bio, "00:") <= 0)
104 goto err;
105 octets++;
106 }
107 if (CBS_len(&cbs) == 0)
108 sep = "";
109 if (BIO_printf(bio, "%c%c%s", tolower(hi), tolower(lo), sep) <= 0)
110 goto err;
111 }
112
113 if (BIO_printf(bio, "\n") <= 0)
114 goto err;
115
116 ret = 1;
117
118 err:
119 freezero(hex, hex_len);
120
121 return ret;
122 }
123
124 int
bn_printf(BIO * bio,const BIGNUM * bn,int indent,const char * fmt,...)125 bn_printf(BIO *bio, const BIGNUM *bn, int indent, const char *fmt, ...)
126 {
127 va_list ap;
128 int rv;
129
130 if (bn == NULL)
131 return 1;
132
133 if (!BIO_indent(bio, indent, 128))
134 return 0;
135
136 va_start(ap, fmt);
137 rv = BIO_vprintf(bio, fmt, ap);
138 va_end(ap);
139 if (rv < 0)
140 return 0;
141
142 if (BN_is_zero(bn))
143 return bn_print_zero(bio, bn);
144
145 if (BN_num_bytes(bn) <= BN_BYTES)
146 return bn_print_word(bio, bn);
147
148 return bn_print_bignum(bio, bn, indent);
149 }
150
151 int
BN_print(BIO * bio,const BIGNUM * bn)152 BN_print(BIO *bio, const BIGNUM *bn)
153 {
154 char *hex = NULL;
155 size_t hex_len = 0;
156 int ret = 0;
157
158 if (!bn_bn2hex_nibbles(bn, &hex, &hex_len))
159 goto err;
160 if (BIO_printf(bio, "%s", hex) <= 0)
161 goto err;
162
163 ret = 1;
164
165 err:
166 freezero(hex, hex_len);
167
168 return ret;
169 }
170 LCRYPTO_ALIAS(BN_print);
171
172 int
BN_print_fp(FILE * fp,const BIGNUM * bn)173 BN_print_fp(FILE *fp, const BIGNUM *bn)
174 {
175 char *hex = NULL;
176 size_t hex_len = 0;
177 int ret = 0;
178
179 if (!bn_bn2hex_nibbles(bn, &hex, &hex_len))
180 goto err;
181 if (fprintf(fp, "%s", hex) < 0)
182 goto err;
183
184 ret = 1;
185
186 err:
187 freezero(hex, hex_len);
188
189 return ret;
190 }
191 LCRYPTO_ALIAS(BN_print_fp);
192