/src/openssl111/crypto/dh/dh_check.c

Source (jump to first uncovered line)
/*
 * Copyright 1995-2023 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 <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include "dh_local.h"

# define DH_NUMBER_ITERATIONS_FOR_PRIME 64

/*-
 * Check that p and g are suitable enough
 *
 * p is odd
 * 1 < g < p - 1
 */
int DH_check_params_ex(const DH *dh)
{
    int errflags = 0;

    if (!DH_check_params(dh, &errflags))
        return 0;

    if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
        DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_CHECK_P_NOT_PRIME);
    if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
        DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_NOT_SUITABLE_GENERATOR);

    return errflags == 0;
}

int DH_check_params(const DH *dh, int *ret)
{
    int ok = 0;
    BIGNUM *tmp = NULL;
    BN_CTX *ctx = NULL;

    *ret = 0;
    ctx = BN_CTX_new();
    if (ctx == NULL)
        goto err;
    BN_CTX_start(ctx);
    tmp = BN_CTX_get(ctx);
    if (tmp == NULL)
        goto err;

    if (!BN_is_odd(dh->p))
        *ret |= DH_CHECK_P_NOT_PRIME;
    if (BN_is_negative(dh->g) || BN_is_zero(dh->g) || BN_is_one(dh->g))
        *ret |= DH_NOT_SUITABLE_GENERATOR;
    if (BN_copy(tmp, dh->p) == NULL || !BN_sub_word(tmp, 1))
        goto err;
    if (BN_cmp(dh->g, tmp) >= 0)
        *ret |= DH_NOT_SUITABLE_GENERATOR;

    ok = 1;
 err:
    BN_CTX_end(ctx);
    BN_CTX_free(ctx);
    return ok;
}

/*-
 * Check that p is a safe prime and
 * g is a suitable generator.
 */
int DH_check_ex(const DH *dh)
{
    int errflags = 0;

    if (!DH_check(dh, &errflags))
        return 0;

    if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_NOT_SUITABLE_GENERATOR);
    if ((errflags & DH_CHECK_Q_NOT_PRIME) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_Q_NOT_PRIME);
    if ((errflags & DH_CHECK_INVALID_Q_VALUE) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_Q_VALUE);
    if ((errflags & DH_CHECK_INVALID_J_VALUE) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_J_VALUE);
    if ((errflags & DH_UNABLE_TO_CHECK_GENERATOR) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_UNABLE_TO_CHECK_GENERATOR);
    if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_PRIME);
    if ((errflags & DH_CHECK_P_NOT_SAFE_PRIME) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_SAFE_PRIME);

    return errflags == 0;
}

int DH_check(const DH *dh, int *ret)
{
    int ok = 0, r, q_good = 0;
    BN_CTX *ctx = NULL;
    BIGNUM *t1 = NULL, *t2 = NULL;

    /* Don't do any checks at all with an excessively large modulus */
    if (BN_num_bits(dh->p) > OPENSSL_DH_CHECK_MAX_MODULUS_BITS) {
        DHerr(DH_F_DH_CHECK, DH_R_MODULUS_TOO_LARGE);
        *ret = DH_CHECK_P_NOT_PRIME;
        return 0;
    }

    if (!DH_check_params(dh, ret))
        return 0;

    ctx = BN_CTX_new();
    if (ctx == NULL)
        goto err;
    BN_CTX_start(ctx);
    t1 = BN_CTX_get(ctx);
    t2 = BN_CTX_get(ctx);
    if (t2 == NULL)
        goto err;

    if (dh->q != NULL) {
        if (BN_ucmp(dh->p, dh->q) > 0)
            q_good = 1;
        else
            *ret |= DH_CHECK_INVALID_Q_VALUE;
    }

    if (q_good) {
        if (BN_cmp(dh->g, BN_value_one()) <= 0)
            *ret |= DH_NOT_SUITABLE_GENERATOR;
        else if (BN_cmp(dh->g, dh->p) >= 0)
            *ret |= DH_NOT_SUITABLE_GENERATOR;
        else {
            /* Check g^q == 1 mod p */
            if (!BN_mod_exp(t1, dh->g, dh->q, dh->p, ctx))
                goto err;
            if (!BN_is_one(t1))
                *ret |= DH_NOT_SUITABLE_GENERATOR;
        }
        r = BN_is_prime_ex(dh->q, DH_NUMBER_ITERATIONS_FOR_PRIME, ctx, NULL);
        if (r < 0)
            goto err;
        if (!r)
            *ret |= DH_CHECK_Q_NOT_PRIME;
        /* Check p == 1 mod q  i.e. q divides p - 1 */
        if (!BN_div(t1, t2, dh->p, dh->q, ctx))
            goto err;
        if (!BN_is_one(t2))
            *ret |= DH_CHECK_INVALID_Q_VALUE;
        if (dh->j && BN_cmp(dh->j, t1))
            *ret |= DH_CHECK_INVALID_J_VALUE;
    }

    r = BN_is_prime_ex(dh->p, DH_NUMBER_ITERATIONS_FOR_PRIME, ctx, NULL);
    if (r < 0)
        goto err;
    if (!r)
        *ret |= DH_CHECK_P_NOT_PRIME;
    else if (!dh->q) {
        if (!BN_rshift1(t1, dh->p))
            goto err;
        r = BN_is_prime_ex(t1, DH_NUMBER_ITERATIONS_FOR_PRIME, ctx, NULL);
        if (r < 0)
            goto err;
        if (!r)
            *ret |= DH_CHECK_P_NOT_SAFE_PRIME;
    }
    ok = 1;
 err:
    BN_CTX_end(ctx);
    BN_CTX_free(ctx);
    return ok;
}

int DH_check_pub_key_ex(const DH *dh, const BIGNUM *pub_key)
{
    int errflags = 0;

    if (!DH_check_pub_key(dh, pub_key, &errflags))
        return 0;

    if ((errflags & DH_CHECK_PUBKEY_TOO_SMALL) != 0)
        DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_SMALL);
    if ((errflags & DH_CHECK_PUBKEY_TOO_LARGE) != 0)
        DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_LARGE);
    if ((errflags & DH_CHECK_PUBKEY_INVALID) != 0)
        DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_INVALID);

    return errflags == 0;
}

int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret)
{
    int ok = 0;
    BIGNUM *tmp = NULL;
    BN_CTX *ctx = NULL;

    *ret = 0;
    ctx = BN_CTX_new();
    if (ctx == NULL)
        goto err;
    BN_CTX_start(ctx);
    tmp = BN_CTX_get(ctx);
    if (tmp == NULL || !BN_set_word(tmp, 1))
        goto err;
    if (BN_cmp(pub_key, tmp) <= 0)
        *ret |= DH_CHECK_PUBKEY_TOO_SMALL;
    if (BN_copy(tmp, dh->p) == NULL || !BN_sub_word(tmp, 1))
        goto err;
    if (BN_cmp(pub_key, tmp) >= 0)
        *ret |= DH_CHECK_PUBKEY_TOO_LARGE;

    if (dh->q != NULL) {
        /* Check pub_key^q == 1 mod p */
        if (!BN_mod_exp(tmp, pub_key, dh->q, dh->p, ctx))
            goto err;
        if (!BN_is_one(tmp))
            *ret |= DH_CHECK_PUBKEY_INVALID;
    }

    ok = 1;
 err:
    BN_CTX_end(ctx);
    BN_CTX_free(ctx);
    return ok;
}

Coverage Report

Created: 2023-09-25 06:45

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 1995-2023 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 <stdio.h>
11		#include "internal/cryptlib.h"
12		#include <openssl/bn.h>
13		#include "dh_local.h"
14
15		# define DH_NUMBER_ITERATIONS_FOR_PRIME 64
16
17		/*-
18		* Check that p and g are suitable enough
19		*
20		* p is odd
21		* 1 < g < p - 1
22		*/
23		int DH_check_params_ex(const DH *dh)
24		{
25		int errflags = 0;
26
27		if (!DH_check_params(dh, &errflags))
28		return 0;
29
30		if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
31		DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_CHECK_P_NOT_PRIME);
32		if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
33		DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_NOT_SUITABLE_GENERATOR);
34
35		return errflags == 0;
36		}
37
38		int DH_check_params(const DH dh, int ret)
39	1.65k	{
40	1.65k	int ok = 0;
41	1.65k	BIGNUM *tmp = NULL;
42	1.65k	BN_CTX *ctx = NULL;
43
44	1.65k	*ret = 0;
45	1.65k	ctx = BN_CTX_new();
46	1.65k	if (ctx == NULL)
47	0	goto err;
48	1.65k	BN_CTX_start(ctx);
49	1.65k	tmp = BN_CTX_get(ctx);
50	1.65k	if (tmp == NULL)
51	0	goto err;
52
53	1.65k	if (!BN_is_odd(dh->p))
54	100	*ret \|= DH_CHECK_P_NOT_PRIME;
55	1.65k	if (BN_is_negative(dh->g) \|\| BN_is_zero(dh->g) \|\| BN_is_one(dh->g))
56	28	*ret \|= DH_NOT_SUITABLE_GENERATOR;
57	1.65k	if (BN_copy(tmp, dh->p) == NULL \|\| !BN_sub_word(tmp, 1))
58	0	goto err;
59	1.65k	if (BN_cmp(dh->g, tmp) >= 0)
60	74	*ret \|= DH_NOT_SUITABLE_GENERATOR;
61
62	1.65k	ok = 1;
63	1.65k	err:
64	1.65k	BN_CTX_end(ctx);
65	1.65k	BN_CTX_free(ctx);
66	1.65k	return ok;
67	1.65k	}
68
69		/*-
70		* Check that p is a safe prime and
71		* g is a suitable generator.
72		*/
73		int DH_check_ex(const DH *dh)
74		{
75		int errflags = 0;
76
77		if (!DH_check(dh, &errflags))
78		return 0;
79
80		if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
81		DHerr(DH_F_DH_CHECK_EX, DH_R_NOT_SUITABLE_GENERATOR);
82		if ((errflags & DH_CHECK_Q_NOT_PRIME) != 0)
83		DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_Q_NOT_PRIME);
84		if ((errflags & DH_CHECK_INVALID_Q_VALUE) != 0)
85		DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_Q_VALUE);
86		if ((errflags & DH_CHECK_INVALID_J_VALUE) != 0)
87		DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_J_VALUE);
88		if ((errflags & DH_UNABLE_TO_CHECK_GENERATOR) != 0)
89		DHerr(DH_F_DH_CHECK_EX, DH_R_UNABLE_TO_CHECK_GENERATOR);
90		if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
91		DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_PRIME);
92		if ((errflags & DH_CHECK_P_NOT_SAFE_PRIME) != 0)
93		DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_SAFE_PRIME);
94
95		return errflags == 0;
96		}
97
98		int DH_check(const DH dh, int ret)
99		{
100		int ok = 0, r, q_good = 0;
101		BN_CTX *ctx = NULL;
102		BIGNUM t1 = NULL, t2 = NULL;
103
104		/* Don't do any checks at all with an excessively large modulus */
105		if (BN_num_bits(dh->p) > OPENSSL_DH_CHECK_MAX_MODULUS_BITS) {
106		DHerr(DH_F_DH_CHECK, DH_R_MODULUS_TOO_LARGE);
107		*ret = DH_CHECK_P_NOT_PRIME;
108		return 0;
109		}
110
111		if (!DH_check_params(dh, ret))
112		return 0;
113
114		ctx = BN_CTX_new();
115		if (ctx == NULL)
116		goto err;
117		BN_CTX_start(ctx);
118		t1 = BN_CTX_get(ctx);
119		t2 = BN_CTX_get(ctx);
120		if (t2 == NULL)
121		goto err;
122
123		if (dh->q != NULL) {
124		if (BN_ucmp(dh->p, dh->q) > 0)
125		q_good = 1;
126		else
127		*ret \|= DH_CHECK_INVALID_Q_VALUE;
128		}
129
130		if (q_good) {
131		if (BN_cmp(dh->g, BN_value_one()) <= 0)
132		*ret \|= DH_NOT_SUITABLE_GENERATOR;
133		else if (BN_cmp(dh->g, dh->p) >= 0)
134		*ret \|= DH_NOT_SUITABLE_GENERATOR;
135		else {
136		/* Check g^q == 1 mod p */
137		if (!BN_mod_exp(t1, dh->g, dh->q, dh->p, ctx))
138		goto err;
139		if (!BN_is_one(t1))
140		*ret \|= DH_NOT_SUITABLE_GENERATOR;
141		}
142		r = BN_is_prime_ex(dh->q, DH_NUMBER_ITERATIONS_FOR_PRIME, ctx, NULL);
143		if (r < 0)
144		goto err;
145		if (!r)
146		*ret \|= DH_CHECK_Q_NOT_PRIME;
147		/* Check p == 1 mod q i.e. q divides p - 1 */
148		if (!BN_div(t1, t2, dh->p, dh->q, ctx))
149		goto err;
150		if (!BN_is_one(t2))
151		*ret \|= DH_CHECK_INVALID_Q_VALUE;
152		if (dh->j && BN_cmp(dh->j, t1))
153		*ret \|= DH_CHECK_INVALID_J_VALUE;
154		}
155
156		r = BN_is_prime_ex(dh->p, DH_NUMBER_ITERATIONS_FOR_PRIME, ctx, NULL);
157		if (r < 0)
158		goto err;
159		if (!r)
160		*ret \|= DH_CHECK_P_NOT_PRIME;
161		else if (!dh->q) {
162		if (!BN_rshift1(t1, dh->p))
163		goto err;
164		r = BN_is_prime_ex(t1, DH_NUMBER_ITERATIONS_FOR_PRIME, ctx, NULL);
165		if (r < 0)
166		goto err;
167		if (!r)
168		*ret \|= DH_CHECK_P_NOT_SAFE_PRIME;
169		}
170		ok = 1;
171		err:
172		BN_CTX_end(ctx);
173		BN_CTX_free(ctx);
174		return ok;
175		}
176
177		int DH_check_pub_key_ex(const DH dh, const BIGNUM pub_key)
178	0	{
179	0	int errflags = 0;
180
181	0	if (!DH_check_pub_key(dh, pub_key, &errflags))
182	0	return 0;
183
184	0	if ((errflags & DH_CHECK_PUBKEY_TOO_SMALL) != 0)
185	0	DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_SMALL);
186	0	if ((errflags & DH_CHECK_PUBKEY_TOO_LARGE) != 0)
187	0	DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_LARGE);
188	0	if ((errflags & DH_CHECK_PUBKEY_INVALID) != 0)
189	0	DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_INVALID);
190
191	0	return errflags == 0;
192	0	}
193
194		int DH_check_pub_key(const DH dh, const BIGNUM pub_key, int *ret)
195	918	{
196	918	int ok = 0;
197	918	BIGNUM *tmp = NULL;
198	918	BN_CTX *ctx = NULL;
199
200	918	*ret = 0;
201	918	ctx = BN_CTX_new();
202	918	if (ctx == NULL)
203	0	goto err;
204	918	BN_CTX_start(ctx);
205	918	tmp = BN_CTX_get(ctx);
206	918	if (tmp == NULL \|\| !BN_set_word(tmp, 1))
207	0	goto err;
208	918	if (BN_cmp(pub_key, tmp) <= 0)
209	2	*ret \|= DH_CHECK_PUBKEY_TOO_SMALL;
210	918	if (BN_copy(tmp, dh->p) == NULL \|\| !BN_sub_word(tmp, 1))
211	0	goto err;
212	918	if (BN_cmp(pub_key, tmp) >= 0)
213	11	*ret \|= DH_CHECK_PUBKEY_TOO_LARGE;
214
215	918	if (dh->q != NULL) {
216		/* Check pub_key^q == 1 mod p */
217	0	if (!BN_mod_exp(tmp, pub_key, dh->q, dh->p, ctx))
218	0	goto err;
219	0	if (!BN_is_one(tmp))
220	0	*ret \|= DH_CHECK_PUBKEY_INVALID;
221	0	}
222
223	918	ok = 1;
224	918	err:
225	918	BN_CTX_end(ctx);
226	918	BN_CTX_free(ctx);
227	918	return ok;
228	918	}