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636b087e MC |
1 | /* |
2 | * Copyright 1995-2017 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 <openssl/err.h> | |
25f2138b | 11 | #include "crypto/ctype.h" |
706457b7 | 12 | #include "bn_local.h" |
636b087e MC |
13 | |
14 | static const char Hex[] = "0123456789ABCDEF"; | |
15 | ||
16 | /* Must 'OPENSSL_free' the returned data */ | |
17 | char *BN_bn2hex(const BIGNUM *a) | |
18 | { | |
19 | int i, j, v, z = 0; | |
20 | char *buf; | |
21 | char *p; | |
22 | ||
23 | if (BN_is_zero(a)) | |
24 | return OPENSSL_strdup("0"); | |
25 | buf = OPENSSL_malloc(a->top * BN_BYTES * 2 + 2); | |
26 | if (buf == NULL) { | |
27 | BNerr(BN_F_BN_BN2HEX, ERR_R_MALLOC_FAILURE); | |
28 | goto err; | |
29 | } | |
30 | p = buf; | |
31 | if (a->neg) | |
32 | *p++ = '-'; | |
33 | for (i = a->top - 1; i >= 0; i--) { | |
34 | for (j = BN_BITS2 - 8; j >= 0; j -= 8) { | |
35 | /* strip leading zeros */ | |
36 | v = (int)((a->d[i] >> j) & 0xff); | |
37 | if (z || v != 0) { | |
38 | *p++ = Hex[v >> 4]; | |
39 | *p++ = Hex[v & 0x0f]; | |
40 | z = 1; | |
41 | } | |
42 | } | |
43 | } | |
44 | *p = '\0'; | |
45 | err: | |
46 | return buf; | |
47 | } | |
48 | ||
f844f9eb RL |
49 | #ifndef FIPS_MODULE |
50 | /* No BIO_snprintf in FIPS_MODULE */ | |
636b087e MC |
51 | /* Must 'OPENSSL_free' the returned data */ |
52 | char *BN_bn2dec(const BIGNUM *a) | |
53 | { | |
54 | int i = 0, num, ok = 0, n, tbytes; | |
55 | char *buf = NULL; | |
56 | char *p; | |
57 | BIGNUM *t = NULL; | |
58 | BN_ULONG *bn_data = NULL, *lp; | |
59 | int bn_data_num; | |
60 | ||
61 | /*- | |
62 | * get an upper bound for the length of the decimal integer | |
63 | * num <= (BN_num_bits(a) + 1) * log(2) | |
64 | * <= 3 * BN_num_bits(a) * 0.101 + log(2) + 1 (rounding error) | |
65 | * <= 3 * BN_num_bits(a) / 10 + 3 * BN_num_bits / 1000 + 1 + 1 | |
66 | */ | |
67 | i = BN_num_bits(a) * 3; | |
68 | num = (i / 10 + i / 1000 + 1) + 1; | |
69 | tbytes = num + 3; /* negative and terminator and one spare? */ | |
70 | bn_data_num = num / BN_DEC_NUM + 1; | |
71 | bn_data = OPENSSL_malloc(bn_data_num * sizeof(BN_ULONG)); | |
72 | buf = OPENSSL_malloc(tbytes); | |
73 | if (buf == NULL || bn_data == NULL) { | |
74 | BNerr(BN_F_BN_BN2DEC, ERR_R_MALLOC_FAILURE); | |
75 | goto err; | |
76 | } | |
77 | if ((t = BN_dup(a)) == NULL) | |
78 | goto err; | |
79 | ||
80 | p = buf; | |
81 | lp = bn_data; | |
82 | if (BN_is_zero(t)) { | |
83 | *p++ = '0'; | |
84 | *p++ = '\0'; | |
85 | } else { | |
86 | if (BN_is_negative(t)) | |
87 | *p++ = '-'; | |
88 | ||
89 | while (!BN_is_zero(t)) { | |
90 | if (lp - bn_data >= bn_data_num) | |
91 | goto err; | |
92 | *lp = BN_div_word(t, BN_DEC_CONV); | |
93 | if (*lp == (BN_ULONG)-1) | |
94 | goto err; | |
95 | lp++; | |
96 | } | |
97 | lp--; | |
98 | /* | |
99 | * We now have a series of blocks, BN_DEC_NUM chars in length, where | |
100 | * the last one needs truncation. The blocks need to be reversed in | |
101 | * order. | |
102 | */ | |
103 | n = BIO_snprintf(p, tbytes - (size_t)(p - buf), BN_DEC_FMT1, *lp); | |
104 | if (n < 0) | |
105 | goto err; | |
106 | p += n; | |
107 | while (lp != bn_data) { | |
108 | lp--; | |
109 | n = BIO_snprintf(p, tbytes - (size_t)(p - buf), BN_DEC_FMT2, *lp); | |
110 | if (n < 0) | |
111 | goto err; | |
112 | p += n; | |
113 | } | |
114 | } | |
115 | ok = 1; | |
116 | err: | |
117 | OPENSSL_free(bn_data); | |
118 | BN_free(t); | |
119 | if (ok) | |
120 | return buf; | |
121 | OPENSSL_free(buf); | |
122 | return NULL; | |
123 | } | |
124 | #endif | |
125 | ||
126 | int BN_hex2bn(BIGNUM **bn, const char *a) | |
127 | { | |
128 | BIGNUM *ret = NULL; | |
129 | BN_ULONG l = 0; | |
130 | int neg = 0, h, m, i, j, k, c; | |
131 | int num; | |
132 | ||
133 | if (a == NULL || *a == '\0') | |
134 | return 0; | |
135 | ||
136 | if (*a == '-') { | |
137 | neg = 1; | |
138 | a++; | |
139 | } | |
140 | ||
141 | for (i = 0; i <= INT_MAX / 4 && ossl_isxdigit(a[i]); i++) | |
142 | continue; | |
143 | ||
144 | if (i == 0 || i > INT_MAX / 4) | |
145 | goto err; | |
146 | ||
147 | num = i + neg; | |
148 | if (bn == NULL) | |
149 | return num; | |
150 | ||
151 | /* a is the start of the hex digits, and it is 'i' long */ | |
152 | if (*bn == NULL) { | |
153 | if ((ret = BN_new()) == NULL) | |
154 | return 0; | |
155 | } else { | |
156 | ret = *bn; | |
157 | BN_zero(ret); | |
158 | } | |
159 | ||
160 | /* i is the number of hex digits */ | |
161 | if (bn_expand(ret, i * 4) == NULL) | |
162 | goto err; | |
163 | ||
164 | j = i; /* least significant 'hex' */ | |
165 | m = 0; | |
166 | h = 0; | |
167 | while (j > 0) { | |
168 | m = (BN_BYTES * 2 <= j) ? BN_BYTES * 2 : j; | |
169 | l = 0; | |
170 | for (;;) { | |
171 | c = a[j - m]; | |
172 | k = OPENSSL_hexchar2int(c); | |
173 | if (k < 0) | |
174 | k = 0; /* paranoia */ | |
175 | l = (l << 4) | k; | |
176 | ||
177 | if (--m <= 0) { | |
178 | ret->d[h++] = l; | |
179 | break; | |
180 | } | |
181 | } | |
182 | j -= BN_BYTES * 2; | |
183 | } | |
184 | ret->top = h; | |
185 | bn_correct_top(ret); | |
186 | ||
187 | *bn = ret; | |
188 | bn_check_top(ret); | |
189 | /* Don't set the negative flag if it's zero. */ | |
190 | if (ret->top != 0) | |
191 | ret->neg = neg; | |
192 | return num; | |
193 | err: | |
194 | if (*bn == NULL) | |
195 | BN_free(ret); | |
196 | return 0; | |
197 | } | |
198 | ||
199 | int BN_dec2bn(BIGNUM **bn, const char *a) | |
200 | { | |
201 | BIGNUM *ret = NULL; | |
202 | BN_ULONG l = 0; | |
203 | int neg = 0, i, j; | |
204 | int num; | |
205 | ||
206 | if (a == NULL || *a == '\0') | |
207 | return 0; | |
208 | if (*a == '-') { | |
209 | neg = 1; | |
210 | a++; | |
211 | } | |
212 | ||
213 | for (i = 0; i <= INT_MAX / 4 && ossl_isdigit(a[i]); i++) | |
214 | continue; | |
215 | ||
216 | if (i == 0 || i > INT_MAX / 4) | |
217 | goto err; | |
218 | ||
219 | num = i + neg; | |
220 | if (bn == NULL) | |
221 | return num; | |
222 | ||
223 | /* | |
224 | * a is the start of the digits, and it is 'i' long. We chop it into | |
225 | * BN_DEC_NUM digits at a time | |
226 | */ | |
227 | if (*bn == NULL) { | |
228 | if ((ret = BN_new()) == NULL) | |
229 | return 0; | |
230 | } else { | |
231 | ret = *bn; | |
232 | BN_zero(ret); | |
233 | } | |
234 | ||
235 | /* i is the number of digits, a bit of an over expand */ | |
236 | if (bn_expand(ret, i * 4) == NULL) | |
237 | goto err; | |
238 | ||
239 | j = BN_DEC_NUM - i % BN_DEC_NUM; | |
240 | if (j == BN_DEC_NUM) | |
241 | j = 0; | |
242 | l = 0; | |
243 | while (--i >= 0) { | |
244 | l *= 10; | |
245 | l += *a - '0'; | |
246 | a++; | |
247 | if (++j == BN_DEC_NUM) { | |
248 | if (!BN_mul_word(ret, BN_DEC_CONV) | |
249 | || !BN_add_word(ret, l)) | |
250 | goto err; | |
251 | l = 0; | |
252 | j = 0; | |
253 | } | |
254 | } | |
255 | ||
256 | bn_correct_top(ret); | |
257 | *bn = ret; | |
258 | bn_check_top(ret); | |
259 | /* Don't set the negative flag if it's zero. */ | |
260 | if (ret->top != 0) | |
261 | ret->neg = neg; | |
262 | return num; | |
263 | err: | |
264 | if (*bn == NULL) | |
265 | BN_free(ret); | |
266 | return 0; | |
267 | } | |
268 | ||
269 | int BN_asc2bn(BIGNUM **bn, const char *a) | |
270 | { | |
271 | const char *p = a; | |
272 | ||
273 | if (*p == '-') | |
274 | p++; | |
275 | ||
276 | if (p[0] == '0' && (p[1] == 'X' || p[1] == 'x')) { | |
277 | if (!BN_hex2bn(bn, p + 2)) | |
278 | return 0; | |
279 | } else { | |
280 | if (!BN_dec2bn(bn, p)) | |
281 | return 0; | |
282 | } | |
283 | /* Don't set the negative flag if it's zero. */ | |
284 | if (*a == '-' && (*bn)->top != 0) | |
285 | (*bn)->neg = 1; | |
286 | return 1; | |
287 | } |