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> |
11 | #include "crypto/ctype.h" |
12 | #include "bn_local.h" |
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 | |
49 | #ifndef FIPS_MODE |
50 | /* No BIO_snprintf in FIPS_MODE */ |
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 | } |
288 | |