Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libcrypto/crypto/../../libssl/src/crypto/dh/dh_key.c	Lines:	70	94	74.5 %
Date:	2016-12-06	Branches:	29	64	45.3 %


/* $OpenBSD: dh_key.c,v 1.25 2016/07/07 11:53:12 bcook 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>

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)
		DHerr(DH_F_GENERATE_KEY, 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) {
		DHerr(DH_F_COMPUTE_KEY, 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) {
		DHerr(DH_F_COMPUTE_KEY, 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) {
		DHerr(DH_F_COMPUTE_KEY, DH_R_INVALID_PUBKEY);
		goto err;
	}

	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->p, ctx,
	    mont)) {
		DHerr(DH_F_COMPUTE_KEY, 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(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 1.25 2016/07/07 11:53:12 bcook 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			static int generate_key(DH *dh);
66			static int compute_key(unsigned char key, const BIGNUM pub_key, DH *dh);
67			static int dh_bn_mod_exp(const DH dh, BIGNUM r, const BIGNUM *a,
68			const BIGNUM p, const BIGNUM m, BN_CTX ctx, BN_MONT_CTX m_ctx);
69			static int dh_init(DH *dh);
70			static int dh_finish(DH *dh);
71
72			int
73			DH_generate_key(DH *dh)
74		18	{
75		18	return dh->meth->generate_key(dh);
76			}
77
78			int
79			DH_compute_key(unsigned char key, const BIGNUM pub_key, DH *dh)
80		18	{
81		18	return dh->meth->compute_key(key, pub_key, dh);
82			}
83
84			static DH_METHOD dh_ossl = {
85			.name = "OpenSSL DH Method",
86			.generate_key = generate_key,
87			.compute_key = compute_key,
88			.bn_mod_exp = dh_bn_mod_exp,
89			.init = dh_init,
90			.finish = dh_finish,
91			};
92
93			const DH_METHOD *
94			DH_OpenSSL(void)
95		2	{
96		2	return &dh_ossl;
97			}
98
99			static int
100			generate_key(DH *dh)
101		18	{
102		18	int ok = 0;
103		18	int generate_new_key = 0;
104			unsigned l;
105			BN_CTX *ctx;
106		18	BN_MONT_CTX *mont = NULL;
107		18	BIGNUM pub_key = NULL, priv_key = NULL;
108
109		18	ctx = BN_CTX_new();
110	✗✓	18	if (ctx == NULL)
111			goto err;
112
113	✓✓	18	if (dh->priv_key == NULL) {
114		1	priv_key = BN_new();
115	✗✓	1	if (priv_key == NULL)
116			goto err;
117		1	generate_new_key = 1;
118			} else
119		17	priv_key = dh->priv_key;
120
121	✓✗	18	if (dh->pub_key == NULL) {
122		18	pub_key = BN_new();
123	✗✓	18	if (pub_key == NULL)
124			goto err;
125			} else
126			pub_key = dh->pub_key;
127
128	✓✗	18	if (dh->flags & DH_FLAG_CACHE_MONT_P) {
129		18	mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
130			CRYPTO_LOCK_DH, dh->p, ctx);
131	✗✓	18	if (!mont)
132			goto err;
133			}
134
135	✓✓	18	if (generate_new_key) {
136	✗✓	1	if (dh->q) {
137			do {
138			if (!BN_rand_range(priv_key, dh->q))
139			goto err;
140			} while (BN_is_zero(priv_key) \|\| BN_is_one(priv_key));
141			} else {
142			/* secret exponent length */
143	✗✓	1	l = dh->length ? dh->length : BN_num_bits(dh->p) - 1;
144	✗✓	1	if (!BN_rand(priv_key, l, 0, 0))
145			goto err;
146			}
147			}
148
149			{
150			BIGNUM prk;
151
152		18	BN_init(&prk);
153		18	BN_with_flags(&prk, priv_key, BN_FLG_CONSTTIME);
154
155	✗✓	18	if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, &prk, dh->p, ctx,
156			mont)) {
157			goto err;
158			}
159			}
160
161		18	dh->pub_key = pub_key;
162		18	dh->priv_key = priv_key;
163		18	ok = 1;
164		18	err:
165	✗✓	18	if (ok != 1)
166			DHerr(DH_F_GENERATE_KEY, ERR_R_BN_LIB);
167
168	✓✗✗✓	18	if (pub_key != NULL && dh->pub_key == NULL)
169			BN_free(pub_key);
170	✓✗✗✓	18	if (priv_key != NULL && dh->priv_key == NULL)
171			BN_free(priv_key);
172		18	BN_CTX_free(ctx);
173		18	return ok;
174			}
175
176			static int
177			compute_key(unsigned char key, const BIGNUM pub_key, DH *dh)
178		18	{
179		18	BN_CTX *ctx = NULL;
180		18	BN_MONT_CTX *mont = NULL;
181			BIGNUM *tmp;
182		18	int ret = -1;
183			int check_result;
184
185	✗✓	18	if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
186			DHerr(DH_F_COMPUTE_KEY, DH_R_MODULUS_TOO_LARGE);
187			goto err;
188			}
189
190		18	ctx = BN_CTX_new();
191	✗✓	18	if (ctx == NULL)
192			goto err;
193		18	BN_CTX_start(ctx);
194	✗✓	18	if ((tmp = BN_CTX_get(ctx)) == NULL)
195			goto err;
196
197	✗✓	18	if (dh->priv_key == NULL) {
198			DHerr(DH_F_COMPUTE_KEY, DH_R_NO_PRIVATE_VALUE);
199			goto err;
200			}
201
202	✓✗	18	if (dh->flags & DH_FLAG_CACHE_MONT_P) {
203		18	mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
204			CRYPTO_LOCK_DH, dh->p, ctx);
205
206		18	BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);
207
208	✗✓	18	if (!mont)
209			goto err;
210			}
211
212	✓✗✗✓	18	if (!DH_check_pub_key(dh, pub_key, &check_result) \|\| check_result) {
213			DHerr(DH_F_COMPUTE_KEY, DH_R_INVALID_PUBKEY);
214			goto err;
215			}
216
217	✗✓	18	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->p, ctx,
218			mont)) {
219			DHerr(DH_F_COMPUTE_KEY, ERR_R_BN_LIB);
220			goto err;
221			}
222
223		18	ret = BN_bn2bin(tmp, key);
224		18	err:
225	✓✗	18	if (ctx != NULL) {
226		18	BN_CTX_end(ctx);
227		18	BN_CTX_free(ctx);
228			}
229		18	return ret;
230			}
231
232			static int
233			dh_bn_mod_exp(const DH dh, BIGNUM r, const BIGNUM a, const BIGNUM p,
234			const BIGNUM m, BN_CTX ctx, BN_MONT_CTX *m_ctx)
235		36	{
236		36	return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx);
237			}
238
239			static int
240			dh_init(DH *dh)
241		18	{
242		18	dh->flags \|= DH_FLAG_CACHE_MONT_P;
243		18	return 1;
244			}
245
246			static int
247			dh_finish(DH *dh)
248		18	{
249		18	BN_MONT_CTX_free(dh->method_mont_p);
250		18	return 1;
251			}