/src/openssl/crypto/bn/bn_blind.c

Source (jump to first uncovered line)
/*
 * Copyright 1998-2018 The OpenSSL Project Authors. 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/opensslconf.h>
#include "internal/cryptlib.h"
#include "bn_lcl.h"

#define BN_BLINDING_COUNTER     32

struct bn_blinding_st {
    BIGNUM *A;
    BIGNUM *Ai;
    BIGNUM *e;
    BIGNUM *mod;                /* just a reference */
    CRYPTO_THREAD_ID tid;
    int counter;
    unsigned long flags;
    BN_MONT_CTX *m_ctx;
    int (*bn_mod_exp) (BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                       const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
    CRYPTO_RWLOCK *lock;
};

BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod)
{
    BN_BLINDING *ret = NULL;

    bn_check_top(mod);

    if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
        BNerr(BN_F_BN_BLINDING_NEW, ERR_R_MALLOC_FAILURE);
        return NULL;
    }

    ret->lock = CRYPTO_THREAD_lock_new();
    if (ret->lock == NULL) {
        BNerr(BN_F_BN_BLINDING_NEW, ERR_R_MALLOC_FAILURE);
        OPENSSL_free(ret);
        return NULL;
    }

    BN_BLINDING_set_current_thread(ret);

    if (A != NULL) {
        if ((ret->A = BN_dup(A)) == NULL)
            goto err;
    }

    if (Ai != NULL) {
        if ((ret->Ai = BN_dup(Ai)) == NULL)
            goto err;
    }

    /* save a copy of mod in the BN_BLINDING structure */
    if ((ret->mod = BN_dup(mod)) == NULL)
        goto err;

    if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)
        BN_set_flags(ret->mod, BN_FLG_CONSTTIME);

    /*
     * Set the counter to the special value -1 to indicate that this is
     * never-used fresh blinding that does not need updating before first
     * use.
     */
    ret->counter = -1;

    return ret;

 err:
    BN_BLINDING_free(ret);
    return NULL;
}

void BN_BLINDING_free(BN_BLINDING *r)
{
    if (r == NULL)
        return;
    BN_free(r->A);
    BN_free(r->Ai);
    BN_free(r->e);
    BN_free(r->mod);
    CRYPTO_THREAD_lock_free(r->lock);
    OPENSSL_free(r);
}

int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)
{
    int ret = 0;

    if ((b->A == NULL) || (b->Ai == NULL)) {
        BNerr(BN_F_BN_BLINDING_UPDATE, BN_R_NOT_INITIALIZED);
        goto err;
    }

    if (b->counter == -1)
        b->counter = 0;

    if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL &&
        !(b->flags & BN_BLINDING_NO_RECREATE)) {
        /* re-create blinding parameters */
        if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
            goto err;
    } else if (!(b->flags & BN_BLINDING_NO_UPDATE)) {
        if (b->m_ctx != NULL) {
            if (!bn_mul_mont_fixed_top(b->Ai, b->Ai, b->Ai, b->m_ctx, ctx)
                || !bn_mul_mont_fixed_top(b->A, b->A, b->A, b->m_ctx, ctx))
                goto err;
        } else {
            if (!BN_mod_mul(b->Ai, b->Ai, b->Ai, b->mod, ctx)
                || !BN_mod_mul(b->A, b->A, b->A, b->mod, ctx))
                goto err;
        }
    }

    ret = 1;
 err:
    if (b->counter == BN_BLINDING_COUNTER)
        b->counter = 0;
    return ret;
}

int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
{
    return BN_BLINDING_convert_ex(n, NULL, b, ctx);
}

int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
{
    int ret = 1;

    bn_check_top(n);

    if ((b->A == NULL) || (b->Ai == NULL)) {
        BNerr(BN_F_BN_BLINDING_CONVERT_EX, BN_R_NOT_INITIALIZED);
        return 0;
    }

    if (b->counter == -1)
        /* Fresh blinding, doesn't need updating. */
        b->counter = 0;
    else if (!BN_BLINDING_update(b, ctx))
        return 0;

    if (r != NULL && (BN_copy(r, b->Ai) == NULL))
        return 0;

    if (b->m_ctx != NULL)
        ret = BN_mod_mul_montgomery(n, n, b->A, b->m_ctx, ctx);
    else
        ret = BN_mod_mul(n, n, b->A, b->mod, ctx);

    return ret;
}

int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
{
    return BN_BLINDING_invert_ex(n, NULL, b, ctx);
}

int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b,
                          BN_CTX *ctx)
{
    int ret;

    bn_check_top(n);

    if (r == NULL && (r = b->Ai) == NULL) {
        BNerr(BN_F_BN_BLINDING_INVERT_EX, BN_R_NOT_INITIALIZED);
        return 0;
    }

    if (b->m_ctx != NULL) {
        /* ensure that BN_mod_mul_montgomery takes pre-defined path */
        if (n->dmax >= r->top) {
            size_t i, rtop = r->top, ntop = n->top;
            BN_ULONG mask;

            for (i = 0; i < rtop; i++) {
                mask = (BN_ULONG)0 - ((i - ntop) >> (8 * sizeof(i) - 1));
                n->d[i] &= mask;
            }
            mask = (BN_ULONG)0 - ((rtop - ntop) >> (8 * sizeof(ntop) - 1));
            /* always true, if (rtop >= ntop) n->top = r->top; */
            n->top = (int)(rtop & ~mask) | (ntop & mask);
            n->flags |= (BN_FLG_FIXED_TOP & ~mask);
        }
        ret = BN_mod_mul_montgomery(n, n, r, b->m_ctx, ctx);
    } else {
        ret = BN_mod_mul(n, n, r, b->mod, ctx);
    }

    bn_check_top(n);
    return ret;
}

int BN_BLINDING_is_current_thread(BN_BLINDING *b)
{
    return CRYPTO_THREAD_compare_id(CRYPTO_THREAD_get_current_id(), b->tid);
}

void BN_BLINDING_set_current_thread(BN_BLINDING *b)
{
    b->tid = CRYPTO_THREAD_get_current_id();
}

int BN_BLINDING_lock(BN_BLINDING *b)
{
    return CRYPTO_THREAD_write_lock(b->lock);
}

int BN_BLINDING_unlock(BN_BLINDING *b)
{
    return CRYPTO_THREAD_unlock(b->lock);
}

unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
{
    return b->flags;
}

void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
{
    b->flags = flags;
}

BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
                                      const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
                                      int (*bn_mod_exp) (BIGNUM *r,
                                                         const BIGNUM *a,
                                                         const BIGNUM *p,
                                                         const BIGNUM *m,
                                                         BN_CTX *ctx,
                                                         BN_MONT_CTX *m_ctx),
                                      BN_MONT_CTX *m_ctx)
{
    int retry_counter = 32;
    BN_BLINDING *ret = NULL;

    if (b == NULL)
        ret = BN_BLINDING_new(NULL, NULL, m);
    else
        ret = b;

    if (ret == NULL)
        goto err;

    if (ret->A == NULL && (ret->A = BN_new()) == NULL)
        goto err;
    if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL)
        goto err;

    if (e != NULL) {
        BN_free(ret->e);
        ret->e = BN_dup(e);
    }
    if (ret->e == NULL)
        goto err;

    if (bn_mod_exp != NULL)
        ret->bn_mod_exp = bn_mod_exp;
    if (m_ctx != NULL)
        ret->m_ctx = m_ctx;

    do {
        int rv;
        if (!BN_priv_rand_range(ret->A, ret->mod))
            goto err;
        if (int_bn_mod_inverse(ret->Ai, ret->A, ret->mod, ctx, &rv))
            break;

        /*
         * this should almost never happen for good RSA keys
         */
        if (!rv)
            goto err;

        if (retry_counter-- == 0) {
            BNerr(BN_F_BN_BLINDING_CREATE_PARAM, BN_R_TOO_MANY_ITERATIONS);
            goto err;
        }
    } while (1);

    if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) {
        if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
            goto err;
    } else {
        if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
            goto err;
    }

    if (ret->m_ctx != NULL) {
        if (!bn_to_mont_fixed_top(ret->Ai, ret->Ai, ret->m_ctx, ctx)
            || !bn_to_mont_fixed_top(ret->A, ret->A, ret->m_ctx, ctx))
            goto err;
    }

    return ret;
 err:
    if (b == NULL) {
        BN_BLINDING_free(ret);
        ret = NULL;
    }

    return ret;
}

Coverage Report

Created: 2018-08-29 13:53

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 1998-2018 The OpenSSL Project Authors. All Rights Reserved.
3		*
4		* Licensed under the OpenSSL license (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/opensslconf.h>
11		#include "internal/cryptlib.h"
12		#include "bn_lcl.h"
13
14	0	#define BN_BLINDING_COUNTER 32
15
16		struct bn_blinding_st {
17		BIGNUM *A;
18		BIGNUM *Ai;
19		BIGNUM *e;
20		BIGNUM mod; / just a reference */
21		CRYPTO_THREAD_ID tid;
22		int counter;
23		unsigned long flags;
24		BN_MONT_CTX *m_ctx;
25		int (bn_mod_exp) (BIGNUM r, const BIGNUM a, const BIGNUM p,
26		const BIGNUM m, BN_CTX ctx, BN_MONT_CTX *m_ctx);
27		CRYPTO_RWLOCK *lock;
28		};
29
30		BN_BLINDING BN_BLINDING_new(const BIGNUM A, const BIGNUM Ai, BIGNUM mod)
31	0	{
32	0	BN_BLINDING *ret = NULL;
33	0
34	0	bn_check_top(mod);
35	0
36	0	if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
37	0	BNerr(BN_F_BN_BLINDING_NEW, ERR_R_MALLOC_FAILURE);
38	0	return NULL;
39	0	}
40	0
41	0	ret->lock = CRYPTO_THREAD_lock_new();
42	0	if (ret->lock == NULL) {
43	0	BNerr(BN_F_BN_BLINDING_NEW, ERR_R_MALLOC_FAILURE);
44	0	OPENSSL_free(ret);
45	0	return NULL;
46	0	}
47	0
48	0	BN_BLINDING_set_current_thread(ret);
49	0
50	0	if (A != NULL) {
51	0	if ((ret->A = BN_dup(A)) == NULL)
52	0	goto err;
53	0	}
54	0
55	0	if (Ai != NULL) {
56	0	if ((ret->Ai = BN_dup(Ai)) == NULL)
57	0	goto err;
58	0	}
59	0
60	0	/* save a copy of mod in the BN_BLINDING structure */
61	0	if ((ret->mod = BN_dup(mod)) == NULL)
62	0	goto err;
63	0
64	0	if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)
65	0	BN_set_flags(ret->mod, BN_FLG_CONSTTIME);
66	0
67	0	/*
68	0	* Set the counter to the special value -1 to indicate that this is
69	0	* never-used fresh blinding that does not need updating before first
70	0	* use.
71	0	*/
72	0	ret->counter = -1;
73	0
74	0	return ret;
75	0
76	0	err:
77	0	BN_BLINDING_free(ret);
78	0	return NULL;
79	0	}
80
81		void BN_BLINDING_free(BN_BLINDING *r)
82	1.08M	{
83	1.08M	if (r == NULL)
84	1.08M	return;
85	0	BN_free(r->A);
86	0	BN_free(r->Ai);
87	0	BN_free(r->e);
88	0	BN_free(r->mod);
89	0	CRYPTO_THREAD_lock_free(r->lock);
90	0	OPENSSL_free(r);
91	0	}
92
93		int BN_BLINDING_update(BN_BLINDING b, BN_CTX ctx)
94	0	{
95	0	int ret = 0;
96	0
97	0	if ((b->A == NULL) \|\| (b->Ai == NULL)) {
98	0	BNerr(BN_F_BN_BLINDING_UPDATE, BN_R_NOT_INITIALIZED);
99	0	goto err;
100	0	}
101	0
102	0	if (b->counter == -1)
103	0	b->counter = 0;
104	0
105	0	if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL &&
106	0	!(b->flags & BN_BLINDING_NO_RECREATE)) {
107	0	/* re-create blinding parameters */
108	0	if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
109	0	goto err;
110	0	} else if (!(b->flags & BN_BLINDING_NO_UPDATE)) {
111	0	if (b->m_ctx != NULL) {
112	0	if (!bn_mul_mont_fixed_top(b->Ai, b->Ai, b->Ai, b->m_ctx, ctx)
113	0	\|\| !bn_mul_mont_fixed_top(b->A, b->A, b->A, b->m_ctx, ctx))
114	0	goto err;
115	0	} else {
116	0	if (!BN_mod_mul(b->Ai, b->Ai, b->Ai, b->mod, ctx)
117	0	\|\| !BN_mod_mul(b->A, b->A, b->A, b->mod, ctx))
118	0	goto err;
119	0	}
120	0	}
121	0
122	0	ret = 1;
123	0	err:
124	0	if (b->counter == BN_BLINDING_COUNTER)
125	0	b->counter = 0;
126	0	return ret;
127	0	}
128
129		int BN_BLINDING_convert(BIGNUM n, BN_BLINDING b, BN_CTX *ctx)
130	0	{
131	0	return BN_BLINDING_convert_ex(n, NULL, b, ctx);
132	0	}
133
134		int BN_BLINDING_convert_ex(BIGNUM n, BIGNUM r, BN_BLINDING b, BN_CTX ctx)
135	0	{
136	0	int ret = 1;
137	0
138	0	bn_check_top(n);
139	0
140	0	if ((b->A == NULL) \|\| (b->Ai == NULL)) {
141	0	BNerr(BN_F_BN_BLINDING_CONVERT_EX, BN_R_NOT_INITIALIZED);
142	0	return 0;
143	0	}
144	0
145	0	if (b->counter == -1)
146	0	/* Fresh blinding, doesn't need updating. */
147	0	b->counter = 0;
148	0	else if (!BN_BLINDING_update(b, ctx))
149	0	return 0;
150	0
151	0	if (r != NULL && (BN_copy(r, b->Ai) == NULL))
152	0	return 0;
153	0
154	0	if (b->m_ctx != NULL)
155	0	ret = BN_mod_mul_montgomery(n, n, b->A, b->m_ctx, ctx);
156	0	else
157	0	ret = BN_mod_mul(n, n, b->A, b->mod, ctx);
158	0
159	0	return ret;
160	0	}
161
162		int BN_BLINDING_invert(BIGNUM n, BN_BLINDING b, BN_CTX *ctx)
163	0	{
164	0	return BN_BLINDING_invert_ex(n, NULL, b, ctx);
165	0	}
166
167		int BN_BLINDING_invert_ex(BIGNUM n, const BIGNUM r, BN_BLINDING *b,
168		BN_CTX *ctx)
169	0	{
170	0	int ret;
171	0
172	0	bn_check_top(n);
173	0
174	0	if (r == NULL && (r = b->Ai) == NULL) {
175	0	BNerr(BN_F_BN_BLINDING_INVERT_EX, BN_R_NOT_INITIALIZED);
176	0	return 0;
177	0	}
178	0
179	0	if (b->m_ctx != NULL) {
180	0	/* ensure that BN_mod_mul_montgomery takes pre-defined path */
181	0	if (n->dmax >= r->top) {
182	0	size_t i, rtop = r->top, ntop = n->top;
183	0	BN_ULONG mask;
184	0
185	0	for (i = 0; i < rtop; i++) {
186	0	mask = (BN_ULONG)0 - ((i - ntop) >> (8 * sizeof(i) - 1));
187	0	n->d[i] &= mask;
188	0	}
189	0	mask = (BN_ULONG)0 - ((rtop - ntop) >> (8 * sizeof(ntop) - 1));
190	0	/* always true, if (rtop >= ntop) n->top = r->top; */
191	0	n->top = (int)(rtop & ~mask) \| (ntop & mask);
192	0	n->flags \|= (BN_FLG_FIXED_TOP & ~mask);
193	0	}
194	0	ret = BN_mod_mul_montgomery(n, n, r, b->m_ctx, ctx);
195	0	} else {
196	0	ret = BN_mod_mul(n, n, r, b->mod, ctx);
197	0	}
198	0
199	0	bn_check_top(n);
200	0	return ret;
201	0	}
202
203		int BN_BLINDING_is_current_thread(BN_BLINDING *b)
204	0	{
205	0	return CRYPTO_THREAD_compare_id(CRYPTO_THREAD_get_current_id(), b->tid);
206	0	}
207
208		void BN_BLINDING_set_current_thread(BN_BLINDING *b)
209	0	{
210	0	b->tid = CRYPTO_THREAD_get_current_id();
211	0	}
212
213		int BN_BLINDING_lock(BN_BLINDING *b)
214	0	{
215	0	return CRYPTO_THREAD_write_lock(b->lock);
216	0	}
217
218		int BN_BLINDING_unlock(BN_BLINDING *b)
219	0	{
220	0	return CRYPTO_THREAD_unlock(b->lock);
221	0	}
222
223		unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
224	0	{
225	0	return b->flags;
226	0	}
227
228		void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
229	0	{
230	0	b->flags = flags;
231	0	}
232
233		BN_BLINDING BN_BLINDING_create_param(BN_BLINDING b,
234		const BIGNUM e, BIGNUM m, BN_CTX *ctx,
235		int (bn_mod_exp) (BIGNUM r,
236		const BIGNUM *a,
237		const BIGNUM *p,
238		const BIGNUM *m,
239		BN_CTX *ctx,
240		BN_MONT_CTX *m_ctx),
241		BN_MONT_CTX *m_ctx)
242	0	{
243	0	int retry_counter = 32;
244	0	BN_BLINDING *ret = NULL;
245	0
246	0	if (b == NULL)
247	0	ret = BN_BLINDING_new(NULL, NULL, m);
248	0	else
249	0	ret = b;
250	0
251	0	if (ret == NULL)
252	0	goto err;
253	0
254	0	if (ret->A == NULL && (ret->A = BN_new()) == NULL)
255	0	goto err;
256	0	if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL)
257	0	goto err;
258	0
259	0	if (e != NULL) {
260	0	BN_free(ret->e);
261	0	ret->e = BN_dup(e);
262	0	}
263	0	if (ret->e == NULL)
264	0	goto err;
265	0
266	0	if (bn_mod_exp != NULL)
267	0	ret->bn_mod_exp = bn_mod_exp;
268	0	if (m_ctx != NULL)
269	0	ret->m_ctx = m_ctx;
270	0
271	0	do {
272	0	int rv;
273	0	if (!BN_priv_rand_range(ret->A, ret->mod))
274	0	goto err;
275	0	if (int_bn_mod_inverse(ret->Ai, ret->A, ret->mod, ctx, &rv))
276	0	break;
277	0
278	0	/*
279	0	* this should almost never happen for good RSA keys
280	0	*/
281	0	if (!rv)
282	0	goto err;
283	0
284	0	if (retry_counter-- == 0) {
285	0	BNerr(BN_F_BN_BLINDING_CREATE_PARAM, BN_R_TOO_MANY_ITERATIONS);
286	0	goto err;
287	0	}
288	0	} while (1);
289	0
290	0	if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) {
291	0	if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
292	0	goto err;
293	0	} else {
294	0	if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
295	0	goto err;
296	0	}
297	0
298	0	if (ret->m_ctx != NULL) {
299	0	if (!bn_to_mont_fixed_top(ret->Ai, ret->Ai, ret->m_ctx, ctx)
300	0	\|\| !bn_to_mont_fixed_top(ret->A, ret->A, ret->m_ctx, ctx))
301	0	goto err;
302	0	}
303	0
304	0	return ret;
305	0	err:
306	0	if (b == NULL) {
307	0	BN_BLINDING_free(ret);
308	0	ret = NULL;
309	0	}
310	0
311	0	return ret;
312	0	}