/src/openssl111/crypto/ec/ecp_mont.c

Source (jump to first uncovered line)
/*
 * Copyright 2001-2019 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <openssl/err.h>

#include "ec_local.h"

const EC_METHOD *EC_GFp_mont_method(void)
{
    static const EC_METHOD ret = {
        EC_FLAGS_DEFAULT_OCT,
        NID_X9_62_prime_field,
        ec_GFp_mont_group_init,
        ec_GFp_mont_group_finish,
        ec_GFp_mont_group_clear_finish,
        ec_GFp_mont_group_copy,
        ec_GFp_mont_group_set_curve,
        ec_GFp_simple_group_get_curve,
        ec_GFp_simple_group_get_degree,
        ec_group_simple_order_bits,
        ec_GFp_simple_group_check_discriminant,
        ec_GFp_simple_point_init,
        ec_GFp_simple_point_finish,
        ec_GFp_simple_point_clear_finish,
        ec_GFp_simple_point_copy,
        ec_GFp_simple_point_set_to_infinity,
        ec_GFp_simple_set_Jprojective_coordinates_GFp,
        ec_GFp_simple_get_Jprojective_coordinates_GFp,
        ec_GFp_simple_point_set_affine_coordinates,
        ec_GFp_simple_point_get_affine_coordinates,
        0, 0, 0,
        ec_GFp_simple_add,
        ec_GFp_simple_dbl,
        ec_GFp_simple_invert,
        ec_GFp_simple_is_at_infinity,
        ec_GFp_simple_is_on_curve,
        ec_GFp_simple_cmp,
        ec_GFp_simple_make_affine,
        ec_GFp_simple_points_make_affine,
        0 /* mul */ ,
        0 /* precompute_mult */ ,
        0 /* have_precompute_mult */ ,
        ec_GFp_mont_field_mul,
        ec_GFp_mont_field_sqr,
        0 /* field_div */ ,
        ec_GFp_mont_field_inv,
        ec_GFp_mont_field_encode,
        ec_GFp_mont_field_decode,
        ec_GFp_mont_field_set_to_one,
        ec_key_simple_priv2oct,
        ec_key_simple_oct2priv,
        0, /* set private */
        ec_key_simple_generate_key,
        ec_key_simple_check_key,
        ec_key_simple_generate_public_key,
        0, /* keycopy */
        0, /* keyfinish */
        ecdh_simple_compute_key,
        0, /* field_inverse_mod_ord */
        ec_GFp_simple_blind_coordinates,
        ec_GFp_simple_ladder_pre,
        ec_GFp_simple_ladder_step,
        ec_GFp_simple_ladder_post
    };

    return &ret;
}

int ec_GFp_mont_group_init(EC_GROUP *group)
{
    int ok;

    ok = ec_GFp_simple_group_init(group);
    group->field_data1 = NULL;
    group->field_data2 = NULL;
    return ok;
}

void ec_GFp_mont_group_finish(EC_GROUP *group)
{
    BN_MONT_CTX_free(group->field_data1);
    group->field_data1 = NULL;
    BN_free(group->field_data2);
    group->field_data2 = NULL;
    ec_GFp_simple_group_finish(group);
}

void ec_GFp_mont_group_clear_finish(EC_GROUP *group)
{
    BN_MONT_CTX_free(group->field_data1);
    group->field_data1 = NULL;
    BN_clear_free(group->field_data2);
    group->field_data2 = NULL;
    ec_GFp_simple_group_clear_finish(group);
}

int ec_GFp_mont_group_copy(EC_GROUP *dest, const EC_GROUP *src)
{
    BN_MONT_CTX_free(dest->field_data1);
    dest->field_data1 = NULL;
    BN_clear_free(dest->field_data2);
    dest->field_data2 = NULL;

    if (!ec_GFp_simple_group_copy(dest, src))
        return 0;

    if (src->field_data1 != NULL) {
        dest->field_data1 = BN_MONT_CTX_new();
        if (dest->field_data1 == NULL)
            return 0;
        if (!BN_MONT_CTX_copy(dest->field_data1, src->field_data1))
            goto err;
    }
    if (src->field_data2 != NULL) {
        dest->field_data2 = BN_dup(src->field_data2);
        if (dest->field_data2 == NULL)
            goto err;
    }

    return 1;

 err:
    BN_MONT_CTX_free(dest->field_data1);
    dest->field_data1 = NULL;
    return 0;
}

int ec_GFp_mont_group_set_curve(EC_GROUP *group, const BIGNUM *p,
                                const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
{
    BN_CTX *new_ctx = NULL;
    BN_MONT_CTX *mont = NULL;
    BIGNUM *one = NULL;
    int ret = 0;

    BN_MONT_CTX_free(group->field_data1);
    group->field_data1 = NULL;
    BN_free(group->field_data2);
    group->field_data2 = NULL;

    if (ctx == NULL) {
        ctx = new_ctx = BN_CTX_new();
        if (ctx == NULL)
            return 0;
    }

    mont = BN_MONT_CTX_new();
    if (mont == NULL)
        goto err;
    if (!BN_MONT_CTX_set(mont, p, ctx)) {
        ECerr(EC_F_EC_GFP_MONT_GROUP_SET_CURVE, ERR_R_BN_LIB);
        goto err;
    }
    one = BN_new();
    if (one == NULL)
        goto err;
    if (!BN_to_montgomery(one, BN_value_one(), mont, ctx))
        goto err;

    group->field_data1 = mont;
    mont = NULL;
    group->field_data2 = one;
    one = NULL;

    ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx);

    if (!ret) {
        BN_MONT_CTX_free(group->field_data1);
        group->field_data1 = NULL;
        BN_free(group->field_data2);
        group->field_data2 = NULL;
    }

 err:
    BN_free(one);
    BN_CTX_free(new_ctx);
    BN_MONT_CTX_free(mont);
    return ret;
}

int ec_GFp_mont_field_mul(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
                          const BIGNUM *b, BN_CTX *ctx)
{
    if (group->field_data1 == NULL) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_MUL, EC_R_NOT_INITIALIZED);
        return 0;
    }

    return BN_mod_mul_montgomery(r, a, b, group->field_data1, ctx);
}

int ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
                          BN_CTX *ctx)
{
    if (group->field_data1 == NULL) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_SQR, EC_R_NOT_INITIALIZED);
        return 0;
    }

    return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx);
}

/*-
 * Computes the multiplicative inverse of a in GF(p), storing the result in r.
 * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
 * We have a Mont structure, so SCA hardening is FLT inversion.
 */
int ec_GFp_mont_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
                            BN_CTX *ctx)
{
    BIGNUM *e = NULL;
    BN_CTX *new_ctx = NULL;
    int ret = 0;

    if (group->field_data1 == NULL)
        return 0;

    if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
        return 0;

    BN_CTX_start(ctx);
    if ((e = BN_CTX_get(ctx)) == NULL)
        goto err;

    /* Inverse in constant time with Fermats Little Theorem */
    if (!BN_set_word(e, 2))
        goto err;
    if (!BN_sub(e, group->field, e))
        goto err;
    /*-
     * Exponent e is public.
     * No need for scatter-gather or BN_FLG_CONSTTIME.
     */
    if (!BN_mod_exp_mont(r, a, e, group->field, ctx, group->field_data1))
        goto err;

    /* throw an error on zero */
    if (BN_is_zero(r)) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_INV, EC_R_CANNOT_INVERT);
        goto err;
    }

    ret = 1;

  err:
    BN_CTX_end(ctx);
    BN_CTX_free(new_ctx);
    return ret;
}

int ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r,
                             const BIGNUM *a, BN_CTX *ctx)
{
    if (group->field_data1 == NULL) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_ENCODE, EC_R_NOT_INITIALIZED);
        return 0;
    }

    return BN_to_montgomery(r, a, (BN_MONT_CTX *)group->field_data1, ctx);
}

int ec_GFp_mont_field_decode(const EC_GROUP *group, BIGNUM *r,
                             const BIGNUM *a, BN_CTX *ctx)
{
    if (group->field_data1 == NULL) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_DECODE, EC_R_NOT_INITIALIZED);
        return 0;
    }

    return BN_from_montgomery(r, a, group->field_data1, ctx);
}

int ec_GFp_mont_field_set_to_one(const EC_GROUP *group, BIGNUM *r,
                                 BN_CTX *ctx)
{
    if (group->field_data2 == NULL) {
        ECerr(EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE, EC_R_NOT_INITIALIZED);
        return 0;
    }

    if (!BN_copy(r, group->field_data2))
        return 0;
    return 1;
}

Coverage Report

Created: 2023-09-25 06:41

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 2001-2019 The OpenSSL Project Authors. All Rights Reserved.
3		* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
4		*
5		* Licensed under the OpenSSL license (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	6.12k	{
17	6.12k	static const EC_METHOD ret = {
18	6.12k	EC_FLAGS_DEFAULT_OCT,
19	6.12k	NID_X9_62_prime_field,
20	6.12k	ec_GFp_mont_group_init,
21	6.12k	ec_GFp_mont_group_finish,
22	6.12k	ec_GFp_mont_group_clear_finish,
23	6.12k	ec_GFp_mont_group_copy,
24	6.12k	ec_GFp_mont_group_set_curve,
25	6.12k	ec_GFp_simple_group_get_curve,
26	6.12k	ec_GFp_simple_group_get_degree,
27	6.12k	ec_group_simple_order_bits,
28	6.12k	ec_GFp_simple_group_check_discriminant,
29	6.12k	ec_GFp_simple_point_init,
30	6.12k	ec_GFp_simple_point_finish,
31	6.12k	ec_GFp_simple_point_clear_finish,
32	6.12k	ec_GFp_simple_point_copy,
33	6.12k	ec_GFp_simple_point_set_to_infinity,
34	6.12k	ec_GFp_simple_set_Jprojective_coordinates_GFp,
35	6.12k	ec_GFp_simple_get_Jprojective_coordinates_GFp,
36	6.12k	ec_GFp_simple_point_set_affine_coordinates,
37	6.12k	ec_GFp_simple_point_get_affine_coordinates,
38	6.12k	0, 0, 0,
39	6.12k	ec_GFp_simple_add,
40	6.12k	ec_GFp_simple_dbl,
41	6.12k	ec_GFp_simple_invert,
42	6.12k	ec_GFp_simple_is_at_infinity,
43	6.12k	ec_GFp_simple_is_on_curve,
44	6.12k	ec_GFp_simple_cmp,
45	6.12k	ec_GFp_simple_make_affine,
46	6.12k	ec_GFp_simple_points_make_affine,
47	6.12k	0 /* mul */ ,
48	6.12k	0 /* precompute_mult */ ,
49	6.12k	0 /* have_precompute_mult */ ,
50	6.12k	ec_GFp_mont_field_mul,
51	6.12k	ec_GFp_mont_field_sqr,
52	6.12k	0 /* field_div */ ,
53	6.12k	ec_GFp_mont_field_inv,
54	6.12k	ec_GFp_mont_field_encode,
55	6.12k	ec_GFp_mont_field_decode,
56	6.12k	ec_GFp_mont_field_set_to_one,
57	6.12k	ec_key_simple_priv2oct,
58	6.12k	ec_key_simple_oct2priv,
59	6.12k	0, /* set private */
60	6.12k	ec_key_simple_generate_key,
61	6.12k	ec_key_simple_check_key,
62	6.12k	ec_key_simple_generate_public_key,
63	6.12k	0, /* keycopy */
64	6.12k	0, /* keyfinish */
65	6.12k	ecdh_simple_compute_key,
66	6.12k	0, /* field_inverse_mod_ord */
67	6.12k	ec_GFp_simple_blind_coordinates,
68	6.12k	ec_GFp_simple_ladder_pre,
69	6.12k	ec_GFp_simple_ladder_step,
70	6.12k	ec_GFp_simple_ladder_post
71	6.12k	};
72
73	6.12k	return &ret;
74	6.12k	}
75
76		int ec_GFp_mont_group_init(EC_GROUP *group)
77	12.2k	{
78	12.2k	int ok;
79
80	12.2k	ok = ec_GFp_simple_group_init(group);
81	12.2k	group->field_data1 = NULL;
82	12.2k	group->field_data2 = NULL;
83	12.2k	return ok;
84	12.2k	}
85
86		void ec_GFp_mont_group_finish(EC_GROUP *group)
87	12.2k	{
88	12.2k	BN_MONT_CTX_free(group->field_data1);
89	12.2k	group->field_data1 = NULL;
90	12.2k	BN_free(group->field_data2);
91	12.2k	group->field_data2 = NULL;
92	12.2k	ec_GFp_simple_group_finish(group);
93	12.2k	}
94
95		void ec_GFp_mont_group_clear_finish(EC_GROUP *group)
96	0	{
97	0	BN_MONT_CTX_free(group->field_data1);
98	0	group->field_data1 = NULL;
99	0	BN_clear_free(group->field_data2);
100	0	group->field_data2 = NULL;
101	0	ec_GFp_simple_group_clear_finish(group);
102	0	}
103
104		int ec_GFp_mont_group_copy(EC_GROUP dest, const EC_GROUP src)
105	6.14k	{
106	6.14k	BN_MONT_CTX_free(dest->field_data1);
107	6.14k	dest->field_data1 = NULL;
108	6.14k	BN_clear_free(dest->field_data2);
109	6.14k	dest->field_data2 = NULL;
110
111	6.14k	if (!ec_GFp_simple_group_copy(dest, src))
112	0	return 0;
113
114	6.14k	if (src->field_data1 != NULL) {
115	6.14k	dest->field_data1 = BN_MONT_CTX_new();
116	6.14k	if (dest->field_data1 == NULL)
117	0	return 0;
118	6.14k	if (!BN_MONT_CTX_copy(dest->field_data1, src->field_data1))
119	0	goto err;
120	6.14k	}
121	6.14k	if (src->field_data2 != NULL) {
122	6.14k	dest->field_data2 = BN_dup(src->field_data2);
123	6.14k	if (dest->field_data2 == NULL)
124	0	goto err;
125	6.14k	}
126
127	6.14k	return 1;
128
129	0	err:
130	0	BN_MONT_CTX_free(dest->field_data1);
131	0	dest->field_data1 = NULL;
132	0	return 0;
133	6.14k	}
134
135		int ec_GFp_mont_group_set_curve(EC_GROUP group, const BIGNUM p,
136		const BIGNUM a, const BIGNUM b, BN_CTX *ctx)
137	6.14k	{
138	6.14k	BN_CTX *new_ctx = NULL;
139	6.14k	BN_MONT_CTX *mont = NULL;
140	6.14k	BIGNUM *one = NULL;
141	6.14k	int ret = 0;
142
143	6.14k	BN_MONT_CTX_free(group->field_data1);
144	6.14k	group->field_data1 = NULL;
145	6.14k	BN_free(group->field_data2);
146	6.14k	group->field_data2 = NULL;
147
148	6.14k	if (ctx == NULL) {
149	0	ctx = new_ctx = BN_CTX_new();
150	0	if (ctx == NULL)
151	0	return 0;
152	0	}
153
154	6.14k	mont = BN_MONT_CTX_new();
155	6.14k	if (mont == NULL)
156	0	goto err;
157	6.14k	if (!BN_MONT_CTX_set(mont, p, ctx)) {
158	0	ECerr(EC_F_EC_GFP_MONT_GROUP_SET_CURVE, ERR_R_BN_LIB);
159	0	goto err;
160	0	}
161	6.14k	one = BN_new();
162	6.14k	if (one == NULL)
163	0	goto err;
164	6.14k	if (!BN_to_montgomery(one, BN_value_one(), mont, ctx))
165	0	goto err;
166
167	6.14k	group->field_data1 = mont;
168	6.14k	mont = NULL;
169	6.14k	group->field_data2 = one;
170	6.14k	one = NULL;
171
172	6.14k	ret = ec_GFp_simple_group_set_curve(group, p, a, b, ctx);
173
174	6.14k	if (!ret) {
175	0	BN_MONT_CTX_free(group->field_data1);
176	0	group->field_data1 = NULL;
177	0	BN_free(group->field_data2);
178	0	group->field_data2 = NULL;
179	0	}
180
181	6.14k	err:
182	6.14k	BN_free(one);
183	6.14k	BN_CTX_free(new_ctx);
184	6.14k	BN_MONT_CTX_free(mont);
185	6.14k	return ret;
186	6.14k	}
187
188		int ec_GFp_mont_field_mul(const EC_GROUP group, BIGNUM r, const BIGNUM *a,
189		const BIGNUM b, BN_CTX ctx)
190	8.91k	{
191	8.91k	if (group->field_data1 == NULL) {
192	0	ECerr(EC_F_EC_GFP_MONT_FIELD_MUL, EC_R_NOT_INITIALIZED);
193	0	return 0;
194	0	}
195
196	8.91k	return BN_mod_mul_montgomery(r, a, b, group->field_data1, ctx);
197	8.91k	}
198
199		int ec_GFp_mont_field_sqr(const EC_GROUP group, BIGNUM r, const BIGNUM *a,
200		BN_CTX *ctx)
201	17.8k	{
202	17.8k	if (group->field_data1 == NULL) {
203	0	ECerr(EC_F_EC_GFP_MONT_FIELD_SQR, EC_R_NOT_INITIALIZED);
204	0	return 0;
205	0	}
206
207	17.8k	return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx);
208	17.8k	}
209
210		/*-
211		* Computes the multiplicative inverse of a in GF(p), storing the result in r.
212		* If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
213		* We have a Mont structure, so SCA hardening is FLT inversion.
214		*/
215		int ec_GFp_mont_field_inv(const EC_GROUP group, BIGNUM r, const BIGNUM *a,
216		BN_CTX *ctx)
217	0	{
218	0	BIGNUM *e = NULL;
219	0	BN_CTX *new_ctx = NULL;
220	0	int ret = 0;
221
222	0	if (group->field_data1 == NULL)
223	0	return 0;
224
225	0	if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
226	0	return 0;
227
228	0	BN_CTX_start(ctx);
229	0	if ((e = BN_CTX_get(ctx)) == NULL)
230	0	goto err;
231
232		/* Inverse in constant time with Fermats Little Theorem */
233	0	if (!BN_set_word(e, 2))
234	0	goto err;
235	0	if (!BN_sub(e, group->field, e))
236	0	goto err;
237		/*-
238		* Exponent e is public.
239		* No need for scatter-gather or BN_FLG_CONSTTIME.
240		*/
241	0	if (!BN_mod_exp_mont(r, a, e, group->field, ctx, group->field_data1))
242	0	goto err;
243
244		/* throw an error on zero */
245	0	if (BN_is_zero(r)) {
246	0	ECerr(EC_F_EC_GFP_MONT_FIELD_INV, EC_R_CANNOT_INVERT);
247	0	goto err;
248	0	}
249
250	0	ret = 1;
251
252	0	err:
253	0	BN_CTX_end(ctx);
254	0	BN_CTX_free(new_ctx);
255	0	return ret;
256	0	}
257
258		int ec_GFp_mont_field_encode(const EC_GROUP group, BIGNUM r,
259		const BIGNUM a, BN_CTX ctx)
260	30.1k	{
261	30.1k	if (group->field_data1 == NULL) {
262	0	ECerr(EC_F_EC_GFP_MONT_FIELD_ENCODE, EC_R_NOT_INITIALIZED);
263	0	return 0;
264	0	}
265
266	30.1k	return BN_to_montgomery(r, a, (BN_MONT_CTX *)group->field_data1, ctx);
267	30.1k	}
268
269		int ec_GFp_mont_field_decode(const EC_GROUP group, BIGNUM r,
270		const BIGNUM a, BN_CTX ctx)
271	9.25k	{
272	9.25k	if (group->field_data1 == NULL) {
273	0	ECerr(EC_F_EC_GFP_MONT_FIELD_DECODE, EC_R_NOT_INITIALIZED);
274	0	return 0;
275	0	}
276
277	9.25k	return BN_from_montgomery(r, a, group->field_data1, ctx);
278	9.25k	}
279
280		int ec_GFp_mont_field_set_to_one(const EC_GROUP group, BIGNUM r,
281		BN_CTX *ctx)
282	8.91k	{
283	8.91k	if (group->field_data2 == NULL) {
284	0	ECerr(EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE, EC_R_NOT_INITIALIZED);
285	0	return 0;
286	0	}
287
288	8.91k	if (!BN_copy(r, group->field_data2))
289	0	return 0;
290	8.91k	return 1;
291	8.91k	}