1 | /* |
2 | * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved. |
3 | * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved |
4 | * |
5 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
6 | * this file except in compliance with the License. You can obtain a copy |
7 | * in the file LICENSE in the source distribution or at |
8 | * https://www.openssl.org/source/license.html |
9 | */ |
10 | |
11 | #include <openssl/err.h> |
12 | |
13 | #include "ec_local.h" |
14 | |
15 | const EC_METHOD *EC_GFp_mont_method(void) |
16 | { |
17 | static const EC_METHOD ret = { |
18 | EC_FLAGS_DEFAULT_OCT, |
19 | NID_X9_62_prime_field, |
20 | ec_GFp_mont_group_init, |
21 | ec_GFp_mont_group_finish, |
22 | ec_GFp_mont_group_clear_finish, |
23 | ec_GFp_mont_group_copy, |
24 | ec_GFp_mont_group_set_curve, |
25 | ec_GFp_simple_group_get_curve, |
26 | ec_GFp_simple_group_get_degree, |
27 | ec_group_simple_order_bits, |
28 | ec_GFp_simple_group_check_discriminant, |
29 | ec_GFp_simple_point_init, |
30 | ec_GFp_simple_point_finish, |
31 | ec_GFp_simple_point_clear_finish, |
32 | ec_GFp_simple_point_copy, |
33 | ec_GFp_simple_point_set_to_infinity, |
34 | ec_GFp_simple_set_Jprojective_coordinates_GFp, |
35 | ec_GFp_simple_get_Jprojective_coordinates_GFp, |
36 | ec_GFp_simple_point_set_affine_coordinates, |
37 | ec_GFp_simple_point_get_affine_coordinates, |
38 | 0, 0, 0, |
39 | ec_GFp_simple_add, |
40 | ec_GFp_simple_dbl, |
41 | ec_GFp_simple_invert, |
42 | ec_GFp_simple_is_at_infinity, |
43 | ec_GFp_simple_is_on_curve, |
44 | ec_GFp_simple_cmp, |
45 | ec_GFp_simple_make_affine, |
46 | ec_GFp_simple_points_make_affine, |
47 | 0 /* mul */ , |
48 | 0 /* precompute_mult */ , |
49 | 0 /* have_precompute_mult */ , |
50 | ec_GFp_mont_field_mul, |
51 | ec_GFp_mont_field_sqr, |
52 | 0 /* field_div */ , |
53 | ec_GFp_mont_field_inv, |
54 | ec_GFp_mont_field_encode, |
55 | ec_GFp_mont_field_decode, |
56 | ec_GFp_mont_field_set_to_one, |
57 | ec_key_simple_priv2oct, |
58 | ec_key_simple_oct2priv, |
59 | 0, /* set private */ |
60 | ec_key_simple_generate_key, |
61 | ec_key_simple_check_key, |
62 | ec_key_simple_generate_public_key, |
63 | 0, /* keycopy */ |
64 | 0, /* keyfinish */ |
65 | ecdh_simple_compute_key, |
66 | ecdsa_simple_sign_setup, |
67 | ecdsa_simple_sign_sig, |
68 | ecdsa_simple_verify_sig, |
69 | 0, /* field_inverse_mod_ord */ |
70 | ec_GFp_simple_blind_coordinates, |
71 | ec_GFp_simple_ladder_pre, |
72 | ec_GFp_simple_ladder_step, |
73 | ec_GFp_simple_ladder_post |
74 | }; |
75 | |
76 | return &ret; |
77 | } |
78 | |
79 | int ec_GFp_mont_group_init(EC_GROUP *group) |
80 | { |
81 | int ok; |
82 | |
83 | ok = ec_GFp_simple_group_init(group); |
84 | group->field_data1 = NULL; |
85 | group->field_data2 = NULL; |
86 | return ok; |
87 | } |
88 | |
89 | void ec_GFp_mont_group_finish(EC_GROUP *group) |
90 | { |
91 | BN_MONT_CTX_free(group->field_data1); |
92 | group->field_data1 = NULL; |
93 | BN_free(group->field_data2); |
94 | group->field_data2 = NULL; |
95 | ec_GFp_simple_group_finish(group); |
96 | } |
97 | |
98 | void ec_GFp_mont_group_clear_finish(EC_GROUP *group) |
99 | { |
100 | BN_MONT_CTX_free(group->field_data1); |
101 | group->field_data1 = NULL; |
102 | BN_clear_free(group->field_data2); |
103 | group->field_data2 = NULL; |
104 | ec_GFp_simple_group_clear_finish(group); |
105 | } |
106 | |
107 | int ec_GFp_mont_group_copy(EC_GROUP *dest, const EC_GROUP *src) |
108 | { |
109 | BN_MONT_CTX_free(dest->field_data1); |
110 | dest->field_data1 = NULL; |
111 | BN_clear_free(dest->field_data2); |
112 | dest->field_data2 = NULL; |
113 | |
114 | if (!ec_GFp_simple_group_copy(dest, src)) |
115 | return 0; |
116 | |
117 | if (src->field_data1 != NULL) { |
118 | dest->field_data1 = BN_MONT_CTX_new(); |
119 | if (dest->field_data1 == NULL) |
120 | return 0; |
121 | if (!BN_MONT_CTX_copy(dest->field_data1, src->field_data1)) |
122 | goto err; |
123 | } |
124 | if (src->field_data2 != NULL) { |
125 | dest->field_data2 = BN_dup(src->field_data2); |
126 | if (dest->field_data2 == NULL) |
127 | goto err; |
128 | } |
129 | |
130 | return 1; |
131 | |
132 | err: |
133 | BN_MONT_CTX_free(dest->field_data1); |
134 | dest->field_data1 = NULL; |
135 | return 0; |
136 | } |
137 | |
138 | int ec_GFp_mont_group_set_curve(EC_GROUP *group, const BIGNUM *p, |
139 | const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) |
140 | { |
141 | BN_CTX *new_ctx = NULL; |
142 | BN_MONT_CTX *mont = NULL; |
143 | BIGNUM *one = NULL; |
144 | int ret = 0; |
145 | |
146 | BN_MONT_CTX_free(group->field_data1); |
147 | group->field_data1 = NULL; |
148 | BN_free(group->field_data2); |
149 | group->field_data2 = NULL; |
150 | |
151 | if (ctx == NULL) { |
152 | ctx = new_ctx = BN_CTX_new_ex(group->libctx); |
153 | if (ctx == NULL) |
154 | return 0; |
155 | } |
156 | |
157 | mont = BN_MONT_CTX_new(); |
158 | if (mont == NULL) |
159 | goto err; |
160 | if (!BN_MONT_CTX_set(mont, p, ctx)) { |
161 | ECerr(EC_F_EC_GFP_MONT_GROUP_SET_CURVE, ERR_R_BN_LIB); |
162 | goto err; |
163 | } |
164 | one = BN_new(); |
165 | if (one == NULL) |
166 | goto err; |
167 | if (!BN_to_montgomery(one, BN_value_one(), mont, ctx)) |
168 | goto err; |
169 | |
170 | group->field_data1 = mont; |
171 | mont = NULL; |
172 | group->field_data2 = one; |
173 | one = NULL; |
174 | |
175 | ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx); |
176 | |
177 | if (!ret) { |
178 | BN_MONT_CTX_free(group->field_data1); |
179 | group->field_data1 = NULL; |
180 | BN_free(group->field_data2); |
181 | group->field_data2 = NULL; |
182 | } |
183 | |
184 | err: |
185 | BN_free(one); |
186 | BN_CTX_free(new_ctx); |
187 | BN_MONT_CTX_free(mont); |
188 | return ret; |
189 | } |
190 | |
191 | int ec_GFp_mont_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, |
192 | const BIGNUM *b, BN_CTX *ctx) |
193 | { |
194 | if (group->field_data1 == NULL) { |
195 | ECerr(EC_F_EC_GFP_MONT_FIELD_MUL, EC_R_NOT_INITIALIZED); |
196 | return 0; |
197 | } |
198 | |
199 | return BN_mod_mul_montgomery(r, a, b, group->field_data1, ctx); |
200 | } |
201 | |
202 | int ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, |
203 | BN_CTX *ctx) |
204 | { |
205 | if (group->field_data1 == NULL) { |
206 | ECerr(EC_F_EC_GFP_MONT_FIELD_SQR, EC_R_NOT_INITIALIZED); |
207 | return 0; |
208 | } |
209 | |
210 | return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx); |
211 | } |
212 | |
213 | /*- |
214 | * Computes the multiplicative inverse of a in GF(p), storing the result in r. |
215 | * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error. |
216 | * We have a Mont structure, so SCA hardening is FLT inversion. |
217 | */ |
218 | int ec_GFp_mont_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a, |
219 | BN_CTX *ctx) |
220 | { |
221 | BIGNUM *e = NULL; |
222 | BN_CTX *new_ctx = NULL; |
223 | int ret = 0; |
224 | |
225 | if (group->field_data1 == NULL) |
226 | return 0; |
227 | |
228 | if (ctx == NULL |
229 | && (ctx = new_ctx = BN_CTX_secure_new_ex(group->libctx)) == NULL) |
230 | return 0; |
231 | |
232 | BN_CTX_start(ctx); |
233 | if ((e = BN_CTX_get(ctx)) == NULL) |
234 | goto err; |
235 | |
236 | /* Inverse in constant time with Fermats Little Theorem */ |
237 | if (!BN_set_word(e, 2)) |
238 | goto err; |
239 | if (!BN_sub(e, group->field, e)) |
240 | goto err; |
241 | /*- |
242 | * Exponent e is public. |
243 | * No need for scatter-gather or BN_FLG_CONSTTIME. |
244 | */ |
245 | if (!BN_mod_exp_mont(r, a, e, group->field, ctx, group->field_data1)) |
246 | goto err; |
247 | |
248 | /* throw an error on zero */ |
249 | if (BN_is_zero(r)) { |
250 | ECerr(EC_F_EC_GFP_MONT_FIELD_INV, EC_R_CANNOT_INVERT); |
251 | goto err; |
252 | } |
253 | |
254 | ret = 1; |
255 | |
256 | err: |
257 | BN_CTX_end(ctx); |
258 | BN_CTX_free(new_ctx); |
259 | return ret; |
260 | } |
261 | |
262 | int ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r, |
263 | const BIGNUM *a, BN_CTX *ctx) |
264 | { |
265 | if (group->field_data1 == NULL) { |
266 | ECerr(EC_F_EC_GFP_MONT_FIELD_ENCODE, EC_R_NOT_INITIALIZED); |
267 | return 0; |
268 | } |
269 | |
270 | return BN_to_montgomery(r, a, (BN_MONT_CTX *)group->field_data1, ctx); |
271 | } |
272 | |
273 | int ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r, |
274 | const BIGNUM *a, BN_CTX *ctx) |
275 | { |
276 | if (group->field_data1 == NULL) { |
277 | ECerr(EC_F_EC_GFP_MONT_FIELD_DECODE, EC_R_NOT_INITIALIZED); |
278 | return 0; |
279 | } |
280 | |
281 | return BN_from_montgomery(r, a, group->field_data1, ctx); |
282 | } |
283 | |
284 | int ec_GFp_mont_field_set_to_one(const EC_GROUP *group, BIGNUM *r, |
285 | BN_CTX *ctx) |
286 | { |
287 | if (group->field_data2 == NULL) { |
288 | ECerr(EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE, EC_R_NOT_INITIALIZED); |
289 | return 0; |
290 | } |
291 | |
292 | if (!BN_copy(r, group->field_data2)) |
293 | return 0; |
294 | return 1; |
295 | } |
296 | |