Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libcrypto/dh/dh_key.c	Lines:	60	74	81.1 %
Date:	2017-11-07	Branches:	32	65	49.2 %


/* $OpenBSD: dh_key.c,v 1.27 2017/01/29 17:49:22 beck Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>

#include <openssl/bn.h>
#include <openssl/dh.h>
#include <openssl/err.h>

#include "bn_lcl.h"

static int generate_key(DH *dh);
static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh);
static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, const BIGNUM *a,
	    const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
static int dh_init(DH *dh);
static int dh_finish(DH *dh);

int
DH_generate_key(DH *dh)
{
	return dh->meth->generate_key(dh);
}

int
DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
{
	return dh->meth->compute_key(key, pub_key, dh);
}

static DH_METHOD dh_ossl = {
	.name = "OpenSSL DH Method",
	.generate_key = generate_key,
	.compute_key = compute_key,
	.bn_mod_exp = dh_bn_mod_exp,
	.init = dh_init,
	.finish = dh_finish,
};

const DH_METHOD *
DH_OpenSSL(void)
{
	return &dh_ossl;
}

static int
generate_key(DH *dh)
{
	int ok = 0;
	int generate_new_key = 0;
	unsigned l;
	BN_CTX *ctx;
	BN_MONT_CTX *mont = NULL;
	BIGNUM *pub_key = NULL, *priv_key = NULL;

	ctx = BN_CTX_new();
	if (ctx == NULL)
		goto err;

	if (dh->priv_key == NULL) {
		priv_key = BN_new();
		if (priv_key == NULL)
			goto err;
		generate_new_key = 1;
	} else
		priv_key = dh->priv_key;

	if (dh->pub_key == NULL) {
		pub_key = BN_new();
		if (pub_key == NULL)
			goto err;
	} else
		pub_key = dh->pub_key;

	if (dh->flags & DH_FLAG_CACHE_MONT_P) {
		mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
		    CRYPTO_LOCK_DH, dh->p, ctx);
		if (!mont)
			goto err;
	}

	if (generate_new_key) {
		if (dh->q) {
			do {
				if (!BN_rand_range(priv_key, dh->q))
					goto err;
			} while (BN_is_zero(priv_key) || BN_is_one(priv_key));
		} else {
			/* secret exponent length */
			l = dh->length ? dh->length : BN_num_bits(dh->p) - 1;
			if (!BN_rand(priv_key, l, 0, 0))
				goto err;
		}
	}

	{
		BIGNUM prk;

		BN_init(&prk);
		BN_with_flags(&prk, priv_key, BN_FLG_CONSTTIME);

		if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, &prk, dh->p, ctx,
		    mont)) {
			goto err;
		}
	}

	dh->pub_key = pub_key;
	dh->priv_key = priv_key;
	ok = 1;
err:
	if (ok != 1)
		DHerror(ERR_R_BN_LIB);

	if (pub_key != NULL && dh->pub_key == NULL)
		BN_free(pub_key);
	if (priv_key != NULL && dh->priv_key == NULL)
		BN_free(priv_key);
	BN_CTX_free(ctx);
	return ok;
}

static int
compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
{
	BN_CTX *ctx = NULL;
	BN_MONT_CTX *mont = NULL;
	BIGNUM *tmp;
	int ret = -1;
        int check_result;

	if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
		DHerror(DH_R_MODULUS_TOO_LARGE);
		goto err;
	}

	ctx = BN_CTX_new();
	if (ctx == NULL)
		goto err;
	BN_CTX_start(ctx);
	if ((tmp = BN_CTX_get(ctx)) == NULL)
		goto err;

	if (dh->priv_key == NULL) {
		DHerror(DH_R_NO_PRIVATE_VALUE);
		goto err;
	}

	if (dh->flags & DH_FLAG_CACHE_MONT_P) {
		mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
		    CRYPTO_LOCK_DH, dh->p, ctx);

		BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);

		if (!mont)
			goto err;
	}

        if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) {
		DHerror(DH_R_INVALID_PUBKEY);
		goto err;
	}

	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->p, ctx,
	    mont)) {
		DHerror(ERR_R_BN_LIB);
		goto err;
	}

	ret = BN_bn2bin(tmp, key);
err:
	if (ctx != NULL) {
		BN_CTX_end(ctx);
		BN_CTX_free(ctx);
	}
	return ret;
}

static int
dh_bn_mod_exp(const DH *dh, BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
    const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx)
{
	return BN_mod_exp_mont_ct(r, a, p, m, ctx, m_ctx);
}

static int
dh_init(DH *dh)
{
	dh->flags |= DH_FLAG_CACHE_MONT_P;
	return 1;
}

static int
dh_finish(DH *dh)
{
	BN_MONT_CTX_free(dh->method_mont_p);
	return 1;
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: dh_key.c,v 1.27 2017/01/29 17:49:22 beck Exp $ */
2			/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3			* All rights reserved.
4			*
5			* This package is an SSL implementation written
6			* by Eric Young (eay@cryptsoft.com).
7			* The implementation was written so as to conform with Netscapes SSL.
8			*
9			* This library is free for commercial and non-commercial use as long as
10			* the following conditions are aheared to. The following conditions
11			* apply to all code found in this distribution, be it the RC4, RSA,
12			* lhash, DES, etc., code; not just the SSL code. The SSL documentation
13			* included with this distribution is covered by the same copyright terms
14			* except that the holder is Tim Hudson (tjh@cryptsoft.com).
15			*
16			* Copyright remains Eric Young's, and as such any Copyright notices in
17			* the code are not to be removed.
18			* If this package is used in a product, Eric Young should be given attribution
19			* as the author of the parts of the library used.
20			* This can be in the form of a textual message at program startup or
21			* in documentation (online or textual) provided with the package.
22			*
23			* Redistribution and use in source and binary forms, with or without
24			* modification, are permitted provided that the following conditions
25			* are met:
26			* 1. Redistributions of source code must retain the copyright
27			* notice, this list of conditions and the following disclaimer.
28			* 2. Redistributions in binary form must reproduce the above copyright
29			* notice, this list of conditions and the following disclaimer in the
30			* documentation and/or other materials provided with the distribution.
31			* 3. All advertising materials mentioning features or use of this software
32			* must display the following acknowledgement:
33			* "This product includes cryptographic software written by
34			* Eric Young (eay@cryptsoft.com)"
35			* The word 'cryptographic' can be left out if the rouines from the library
36			* being used are not cryptographic related :-).
37			* 4. If you include any Windows specific code (or a derivative thereof) from
38			* the apps directory (application code) you must include an acknowledgement:
39			* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40			*
41			* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44			* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51			* SUCH DAMAGE.
52			*
53			* The licence and distribution terms for any publically available version or
54			* derivative of this code cannot be changed. i.e. this code cannot simply be
55			* copied and put under another distribution licence
56			* [including the GNU Public Licence.]
57			*/
58
59			#include <stdio.h>
60
61			#include <openssl/bn.h>
62			#include <openssl/dh.h>
63			#include <openssl/err.h>
64
65			#include "bn_lcl.h"
66
67			static int generate_key(DH *dh);
68			static int compute_key(unsigned char key, const BIGNUM pub_key, DH *dh);
69			static int dh_bn_mod_exp(const DH dh, BIGNUM r, const BIGNUM *a,
70			const BIGNUM p, const BIGNUM m, BN_CTX ctx, BN_MONT_CTX m_ctx);
71			static int dh_init(DH *dh);
72			static int dh_finish(DH *dh);
73
74			int
75			DH_generate_key(DH *dh)
76			{
77		736	return dh->meth->generate_key(dh);
78			}
79
80			int
81			DH_compute_key(unsigned char key, const BIGNUM pub_key, DH *dh)
82			{
83		712	return dh->meth->compute_key(key, pub_key, dh);
84			}
85
86			static DH_METHOD dh_ossl = {
87			.name = "OpenSSL DH Method",
88			.generate_key = generate_key,
89			.compute_key = compute_key,
90			.bn_mod_exp = dh_bn_mod_exp,
91			.init = dh_init,
92			.finish = dh_finish,
93			};
94
95			const DH_METHOD *
96			DH_OpenSSL(void)
97			{
98		2838	return &dh_ossl;
99			}
100
101			static int
102			generate_key(DH *dh)
103			{
104			int ok = 0;
105			int generate_new_key = 0;
106			unsigned l;
107			BN_CTX *ctx;
108			BN_MONT_CTX *mont = NULL;
109			BIGNUM pub_key = NULL, priv_key = NULL;
110
111		736	ctx = BN_CTX_new();
112	✓✗	368	if (ctx == NULL)
113			goto err;
114
115	✓✓	368	if (dh->priv_key == NULL) {
116		264	priv_key = BN_new();
117	✓✗	264	if (priv_key == NULL)
118			goto err;
119			generate_new_key = 1;
120		264	} else
121			priv_key = dh->priv_key;
122
123	✓✗	368	if (dh->pub_key == NULL) {
124		368	pub_key = BN_new();
125	✓✗	368	if (pub_key == NULL)
126			goto err;
127			} else
128			pub_key = dh->pub_key;
129
130	✓✗	368	if (dh->flags & DH_FLAG_CACHE_MONT_P) {
131		736	mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
132		368	CRYPTO_LOCK_DH, dh->p, ctx);
133	✓✗	368	if (!mont)
134			goto err;
135			}
136
137	✓✓	368	if (generate_new_key) {
138	✗✓	264	if (dh->q) {
139			do {
140			if (!BN_rand_range(priv_key, dh->q))
141			goto err;
142			} while (BN_is_zero(priv_key) \|\| BN_is_one(priv_key));
143			} else {
144			/* secret exponent length */
145	✓✓	792	l = dh->length ? dh->length : BN_num_bits(dh->p) - 1;
146	✓✗	264	if (!BN_rand(priv_key, l, 0, 0))
147			goto err;
148			}
149			}
150
151			{
152		368	BIGNUM prk;
153
154		368	BN_init(&prk);
155		368	BN_with_flags(&prk, priv_key, BN_FLG_CONSTTIME);
156
157	✗✓	368	if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, &prk, dh->p, ctx,
158			mont)) {
159			goto err;
160			}
161	✓✓✓	1472	}
162
163		368	dh->pub_key = pub_key;
164		368	dh->priv_key = priv_key;
165		368	ok = 1;
166			err:
167	✗✓	368	if (ok != 1)
168			DHerror(ERR_R_BN_LIB);
169
170	✓✗✗✓	736	if (pub_key != NULL && dh->pub_key == NULL)
171			BN_free(pub_key);
172	✓✗✗✓	736	if (priv_key != NULL && dh->priv_key == NULL)
173			BN_free(priv_key);
174		368	BN_CTX_free(ctx);
175		368	return ok;
176		368	}
177
178			static int
179			compute_key(unsigned char key, const BIGNUM pub_key, DH *dh)
180			{
181			BN_CTX *ctx = NULL;
182			BN_MONT_CTX *mont = NULL;
183			BIGNUM *tmp;
184			int ret = -1;
185		712	int check_result;
186
187	✗✓	356	if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
188			DHerror(DH_R_MODULUS_TOO_LARGE);
189			goto err;
190			}
191
192		356	ctx = BN_CTX_new();
193	✓✗	356	if (ctx == NULL)
194			goto err;
195		356	BN_CTX_start(ctx);
196	✓✗	356	if ((tmp = BN_CTX_get(ctx)) == NULL)
197			goto err;
198
199	✗✓	356	if (dh->priv_key == NULL) {
200			DHerror(DH_R_NO_PRIVATE_VALUE);
201			goto err;
202			}
203
204	✓✗	356	if (dh->flags & DH_FLAG_CACHE_MONT_P) {
205		712	mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
206		356	CRYPTO_LOCK_DH, dh->p, ctx);
207
208		356	BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);
209
210	✓✗	356	if (!mont)
211			goto err;
212			}
213
214	✗✓	356	if (!DH_check_pub_key(dh, pub_key, &check_result) \|\| check_result) {
215			DHerror(DH_R_INVALID_PUBKEY);
216			goto err;
217			}
218
219	✗✓	356	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->p, ctx,
220			mont)) {
221			DHerror(ERR_R_BN_LIB);
222			goto err;
223			}
224
225		356	ret = BN_bn2bin(tmp, key);
226			err:
227	✓✗	356	if (ctx != NULL) {
228		356	BN_CTX_end(ctx);
229		356	BN_CTX_free(ctx);
230		356	}
231		356	return ret;
232		356	}
233
234			static int
235			dh_bn_mod_exp(const DH dh, BIGNUM r, const BIGNUM a, const BIGNUM p,
236			const BIGNUM m, BN_CTX ctx, BN_MONT_CTX *m_ctx)
237			{
238		1448	return BN_mod_exp_mont_ct(r, a, p, m, ctx, m_ctx);
239			}
240
241			static int
242			dh_init(DH *dh)
243			{
244		4708	dh->flags \|= DH_FLAG_CACHE_MONT_P;
245		2354	return 1;
246			}
247
248			static int
249			dh_finish(DH *dh)
250			{
251		2344	BN_MONT_CTX_free(dh->method_mont_p);
252		1172	return 1;
253			}