/src/openssl/crypto/dh/dh_check.c

Source (jump to first uncovered line)
/*
 * Copyright 1995-2024 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (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
 */

/*
 * DH low level APIs are deprecated for public use, but still ok for
 * internal use.
 */
#include "internal/deprecated.h"

#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include "dh_local.h"
#include "crypto/dh.h"

/*-
 * 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)
        ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_PRIME);
    if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_NOT_SUITABLE_GENERATOR);
    if ((errflags & DH_MODULUS_TOO_SMALL) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL);
    if ((errflags & DH_MODULUS_TOO_LARGE) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);

    return errflags == 0;
}

#ifdef FIPS_MODULE
int DH_check_params(const DH *dh, int *ret)
{
    int nid;

    *ret = 0;
    /*
     * SP800-56A R3 Section 5.5.2 Assurances of Domain Parameter Validity
     * (1a) The domain parameters correspond to any approved safe prime group.
     */
    nid = DH_get_nid((DH *)dh);
    if (nid != NID_undef)
        return 1;
    /*
     * OR
     * (2b) FFC domain params conform to FIPS-186-4 explicit domain param
     * validity tests.
     */
    return ossl_ffc_params_FIPS186_4_validate(dh->libctx, &dh->params,
                                              FFC_PARAM_TYPE_DH, ret, NULL);
}
#else
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_ex(dh->libctx);
    if (ctx == NULL)
        goto err;
    BN_CTX_start(ctx);
    tmp = BN_CTX_get(ctx);
    if (tmp == NULL)
        goto err;

    if (!BN_is_odd(dh->params.p))
        *ret |= DH_CHECK_P_NOT_PRIME;
    if (BN_is_negative(dh->params.g)
        || BN_is_zero(dh->params.g)
        || BN_is_one(dh->params.g))
        *ret |= DH_NOT_SUITABLE_GENERATOR;
    if (BN_copy(tmp, dh->params.p) == NULL || !BN_sub_word(tmp, 1))
        goto err;
    if (BN_cmp(dh->params.g, tmp) >= 0)
        *ret |= DH_NOT_SUITABLE_GENERATOR;
    if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS)
        *ret |= DH_MODULUS_TOO_SMALL;
    if (BN_num_bits(dh->params.p) > OPENSSL_DH_MAX_MODULUS_BITS)
        *ret |= DH_MODULUS_TOO_LARGE;

    ok = 1;
 err:
    BN_CTX_end(ctx);
    BN_CTX_free(ctx);
    return ok;
}
#endif /* FIPS_MODULE */

/*-
 * 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)
        ERR_raise(ERR_LIB_DH, DH_R_NOT_SUITABLE_GENERATOR);
    if ((errflags & DH_CHECK_Q_NOT_PRIME) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_CHECK_Q_NOT_PRIME);
    if ((errflags & DH_CHECK_INVALID_Q_VALUE) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_CHECK_INVALID_Q_VALUE);
    if ((errflags & DH_CHECK_INVALID_J_VALUE) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_CHECK_INVALID_J_VALUE);
    if ((errflags & DH_UNABLE_TO_CHECK_GENERATOR) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_UNABLE_TO_CHECK_GENERATOR);
    if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_PRIME);
    if ((errflags & DH_CHECK_P_NOT_SAFE_PRIME) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_SAFE_PRIME);
    if ((errflags & DH_MODULUS_TOO_SMALL) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL);
    if ((errflags & DH_MODULUS_TOO_LARGE) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);

    return errflags == 0;
}

/* Note: according to documentation - this only checks the params */
int DH_check(const DH *dh, int *ret)
{
#ifdef FIPS_MODULE
    return DH_check_params(dh, ret);
#else
    int ok = 0, r, q_good = 0;
    BN_CTX *ctx = NULL;
    BIGNUM *t1 = NULL, *t2 = NULL;
    int nid = DH_get_nid((DH *)dh);

    *ret = 0;
    if (nid != NID_undef)
        return 1;

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

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

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

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

    r = BN_check_prime(dh->params.p, ctx, NULL);
    if (r < 0)
        goto err;
    if (!r)
        *ret |= DH_CHECK_P_NOT_PRIME;
    else if (dh->params.q == NULL) {
        if (!BN_rshift1(t1, dh->params.p))
            goto err;
        r = BN_check_prime(t1, 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;
#endif /* FIPS_MODULE */
}

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)
        ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_TOO_SMALL);
    if ((errflags & DH_CHECK_PUBKEY_TOO_LARGE) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_TOO_LARGE);
    if ((errflags & DH_CHECK_PUBKEY_INVALID) != 0)
        ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_INVALID);

    return errflags == 0;
}

/*
 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation.
 */
int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret)
{
    /* Don't do any checks at all with an excessively large modulus */
    if (BN_num_bits(dh->params.p) > OPENSSL_DH_CHECK_MAX_MODULUS_BITS) {
        ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
        *ret = DH_MODULUS_TOO_LARGE | DH_CHECK_PUBKEY_INVALID;
        return 0;
    }

    if (dh->params.q != NULL && BN_ucmp(dh->params.p, dh->params.q) < 0) {
        *ret |= DH_CHECK_INVALID_Q_VALUE | DH_CHECK_PUBKEY_INVALID;
        return 1;
    }

    return ossl_ffc_validate_public_key(&dh->params, pub_key, ret);
}

/*
 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Partial public key validation.
 * To only be used with ephemeral FFC public keys generated using the approved
 * safe-prime groups.
 */
int ossl_dh_check_pub_key_partial(const DH *dh, const BIGNUM *pub_key, int *ret)
{
    return ossl_ffc_validate_public_key_partial(&dh->params, pub_key, ret)
           && *ret == 0;
}

int ossl_dh_check_priv_key(const DH *dh, const BIGNUM *priv_key, int *ret)
{
    int ok = 0;
    BIGNUM *two_powN = NULL, *upper;

    *ret = 0;
    two_powN = BN_new();
    if (two_powN == NULL)
        return 0;

    if (dh->params.q != NULL) {
        upper = dh->params.q;
#ifndef FIPS_MODULE
    } else if (dh->params.p != NULL) {
        /*
         * We do not have q so we just check the key is within some
         * reasonable range, or the number of bits is equal to dh->length.
         */
        int length = dh->length;

        if (length == 0) {
            length = BN_num_bits(dh->params.p) - 1;
            if (BN_num_bits(priv_key) <= length
                && BN_num_bits(priv_key) > 1)
                ok = 1;
        } else if (BN_num_bits(priv_key) == length) {
            ok = 1;
        }
        goto end;
#endif
    } else {
        goto end;
    }

    /* Is it from an approved Safe prime group ?*/
    if (DH_get_nid((DH *)dh) != NID_undef && dh->length != 0) {
        if (!BN_lshift(two_powN, BN_value_one(), dh->length))
            goto end;
        if (BN_cmp(two_powN, dh->params.q) < 0)
            upper = two_powN;
    }
    if (!ossl_ffc_validate_private_key(upper, priv_key, ret))
        goto end;

    ok = 1;
end:
    BN_free(two_powN);
    return ok;
}

/*
 * FFC pairwise check from SP800-56A R3.
 *    Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
 */
int ossl_dh_check_pairwise(const DH *dh)
{
    int ret = 0;
    BN_CTX *ctx = NULL;
    BIGNUM *pub_key = NULL;

    if (dh->params.p == NULL
        || dh->params.g == NULL
        || dh->priv_key == NULL
        || dh->pub_key == NULL)
        return 0;

    ctx = BN_CTX_new_ex(dh->libctx);
    if (ctx == NULL)
        goto err;
    pub_key = BN_new();
    if (pub_key == NULL)
        goto err;

    /* recalculate the public key = (g ^ priv) mod p */
    if (!ossl_dh_generate_public_key(ctx, dh, dh->priv_key, pub_key))
        goto err;
    /* check it matches the existing public_key */
    ret = BN_cmp(pub_key, dh->pub_key) == 0;
err:
    BN_free(pub_key);
    BN_CTX_free(ctx);
    return ret;
}

Coverage Report

Created: 2025-06-22 06:56

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 1995-2024 The OpenSSL Project Authors. All Rights Reserved.
3		*
4		* Licensed under the Apache License 2.0 (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		/*
11		* DH low level APIs are deprecated for public use, but still ok for
12		* internal use.
13		*/
14		#include "internal/deprecated.h"
15
16		#include <stdio.h>
17		#include "internal/cryptlib.h"
18		#include <openssl/bn.h>
19		#include "dh_local.h"
20		#include "crypto/dh.h"
21
22		/*-
23		* Check that p and g are suitable enough
24		*
25		* p is odd
26		* 1 < g < p - 1
27		*/
28		int DH_check_params_ex(const DH *dh)
29	0	{
30	0	int errflags = 0;
31
32	0	if (!DH_check_params(dh, &errflags))
33	0	return 0;
34
35	0	if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
36	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_PRIME);
37	0	if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
38	0	ERR_raise(ERR_LIB_DH, DH_R_NOT_SUITABLE_GENERATOR);
39	0	if ((errflags & DH_MODULUS_TOO_SMALL) != 0)
40	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL);
41	0	if ((errflags & DH_MODULUS_TOO_LARGE) != 0)
42	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
43
44	0	return errflags == 0;
45	0	}
46
47		#ifdef FIPS_MODULE
48		int DH_check_params(const DH dh, int ret)
49		{
50		int nid;
51
52		*ret = 0;
53		/*
54		* SP800-56A R3 Section 5.5.2 Assurances of Domain Parameter Validity
55		* (1a) The domain parameters correspond to any approved safe prime group.
56		*/
57		nid = DH_get_nid((DH *)dh);
58		if (nid != NID_undef)
59		return 1;
60		/*
61		* OR
62		* (2b) FFC domain params conform to FIPS-186-4 explicit domain param
63		* validity tests.
64		*/
65		return ossl_ffc_params_FIPS186_4_validate(dh->libctx, &dh->params,
66		FFC_PARAM_TYPE_DH, ret, NULL);
67		}
68		#else
69		int DH_check_params(const DH dh, int ret)
70	0	{
71	0	int ok = 0;
72	0	BIGNUM *tmp = NULL;
73	0	BN_CTX *ctx = NULL;
74
75	0	*ret = 0;
76	0	ctx = BN_CTX_new_ex(dh->libctx);
77	0	if (ctx == NULL)
78	0	goto err;
79	0	BN_CTX_start(ctx);
80	0	tmp = BN_CTX_get(ctx);
81	0	if (tmp == NULL)
82	0	goto err;
83
84	0	if (!BN_is_odd(dh->params.p))
85	0	*ret \|= DH_CHECK_P_NOT_PRIME;
86	0	if (BN_is_negative(dh->params.g)
87	0	\|\| BN_is_zero(dh->params.g)
88	0	\|\| BN_is_one(dh->params.g))
89	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
90	0	if (BN_copy(tmp, dh->params.p) == NULL \|\| !BN_sub_word(tmp, 1))
91	0	goto err;
92	0	if (BN_cmp(dh->params.g, tmp) >= 0)
93	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
94	0	if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS)
95	0	*ret \|= DH_MODULUS_TOO_SMALL;
96	0	if (BN_num_bits(dh->params.p) > OPENSSL_DH_MAX_MODULUS_BITS)
97	0	*ret \|= DH_MODULUS_TOO_LARGE;
98
99	0	ok = 1;
100	0	err:
101	0	BN_CTX_end(ctx);
102	0	BN_CTX_free(ctx);
103	0	return ok;
104	0	}
105		#endif /* FIPS_MODULE */
106
107		/*-
108		* Check that p is a safe prime and
109		* g is a suitable generator.
110		*/
111		int DH_check_ex(const DH *dh)
112	0	{
113	0	int errflags = 0;
114
115	0	if (!DH_check(dh, &errflags))
116	0	return 0;
117
118	0	if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
119	0	ERR_raise(ERR_LIB_DH, DH_R_NOT_SUITABLE_GENERATOR);
120	0	if ((errflags & DH_CHECK_Q_NOT_PRIME) != 0)
121	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_Q_NOT_PRIME);
122	0	if ((errflags & DH_CHECK_INVALID_Q_VALUE) != 0)
123	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_INVALID_Q_VALUE);
124	0	if ((errflags & DH_CHECK_INVALID_J_VALUE) != 0)
125	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_INVALID_J_VALUE);
126	0	if ((errflags & DH_UNABLE_TO_CHECK_GENERATOR) != 0)
127	0	ERR_raise(ERR_LIB_DH, DH_R_UNABLE_TO_CHECK_GENERATOR);
128	0	if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
129	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_PRIME);
130	0	if ((errflags & DH_CHECK_P_NOT_SAFE_PRIME) != 0)
131	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_SAFE_PRIME);
132	0	if ((errflags & DH_MODULUS_TOO_SMALL) != 0)
133	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL);
134	0	if ((errflags & DH_MODULUS_TOO_LARGE) != 0)
135	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
136
137	0	return errflags == 0;
138	0	}
139
140		/* Note: according to documentation - this only checks the params */
141		int DH_check(const DH dh, int ret)
142	0	{
143		#ifdef FIPS_MODULE
144		return DH_check_params(dh, ret);
145		#else
146	0	int ok = 0, r, q_good = 0;
147	0	BN_CTX *ctx = NULL;
148	0	BIGNUM t1 = NULL, t2 = NULL;
149	0	int nid = DH_get_nid((DH *)dh);
150
151	0	*ret = 0;
152	0	if (nid != NID_undef)
153	0	return 1;
154
155		/* Don't do any checks at all with an excessively large modulus */
156	0	if (BN_num_bits(dh->params.p) > OPENSSL_DH_CHECK_MAX_MODULUS_BITS) {
157	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
158	0	*ret = DH_MODULUS_TOO_LARGE \| DH_CHECK_P_NOT_PRIME;
159	0	return 0;
160	0	}
161
162	0	if (!DH_check_params(dh, ret))
163	0	return 0;
164
165	0	ctx = BN_CTX_new_ex(dh->libctx);
166	0	if (ctx == NULL)
167	0	goto err;
168	0	BN_CTX_start(ctx);
169	0	t1 = BN_CTX_get(ctx);
170	0	t2 = BN_CTX_get(ctx);
171	0	if (t2 == NULL)
172	0	goto err;
173
174	0	if (dh->params.q != NULL) {
175	0	if (BN_ucmp(dh->params.p, dh->params.q) > 0)
176	0	q_good = 1;
177	0	else
178	0	*ret \|= DH_CHECK_INVALID_Q_VALUE;
179	0	}
180
181	0	if (q_good) {
182	0	if (BN_cmp(dh->params.g, BN_value_one()) <= 0)
183	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
184	0	else if (BN_cmp(dh->params.g, dh->params.p) >= 0)
185	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
186	0	else {
187		/* Check g^q == 1 mod p */
188	0	if (!BN_mod_exp(t1, dh->params.g, dh->params.q, dh->params.p, ctx))
189	0	goto err;
190	0	if (!BN_is_one(t1))
191	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
192	0	}
193	0	r = BN_check_prime(dh->params.q, ctx, NULL);
194	0	if (r < 0)
195	0	goto err;
196	0	if (!r)
197	0	*ret \|= DH_CHECK_Q_NOT_PRIME;
198		/* Check p == 1 mod q i.e. q divides p - 1 */
199	0	if (!BN_div(t1, t2, dh->params.p, dh->params.q, ctx))
200	0	goto err;
201	0	if (!BN_is_one(t2))
202	0	*ret \|= DH_CHECK_INVALID_Q_VALUE;
203	0	if (dh->params.j != NULL
204	0	&& BN_cmp(dh->params.j, t1))
205	0	*ret \|= DH_CHECK_INVALID_J_VALUE;
206	0	}
207
208	0	r = BN_check_prime(dh->params.p, ctx, NULL);
209	0	if (r < 0)
210	0	goto err;
211	0	if (!r)
212	0	*ret \|= DH_CHECK_P_NOT_PRIME;
213	0	else if (dh->params.q == NULL) {
214	0	if (!BN_rshift1(t1, dh->params.p))
215	0	goto err;
216	0	r = BN_check_prime(t1, ctx, NULL);
217	0	if (r < 0)
218	0	goto err;
219	0	if (!r)
220	0	*ret \|= DH_CHECK_P_NOT_SAFE_PRIME;
221	0	}
222	0	ok = 1;
223	0	err:
224	0	BN_CTX_end(ctx);
225	0	BN_CTX_free(ctx);
226	0	return ok;
227	0	#endif /* FIPS_MODULE */
228	0	}
229
230		int DH_check_pub_key_ex(const DH dh, const BIGNUM pub_key)
231	0	{
232	0	int errflags = 0;
233
234	0	if (!DH_check_pub_key(dh, pub_key, &errflags))
235	0	return 0;
236
237	0	if ((errflags & DH_CHECK_PUBKEY_TOO_SMALL) != 0)
238	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_TOO_SMALL);
239	0	if ((errflags & DH_CHECK_PUBKEY_TOO_LARGE) != 0)
240	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_TOO_LARGE);
241	0	if ((errflags & DH_CHECK_PUBKEY_INVALID) != 0)
242	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_INVALID);
243
244	0	return errflags == 0;
245	0	}
246
247		/*
248		* See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation.
249		*/
250		int DH_check_pub_key(const DH dh, const BIGNUM pub_key, int *ret)
251	0	{
252		/* Don't do any checks at all with an excessively large modulus */
253	0	if (BN_num_bits(dh->params.p) > OPENSSL_DH_CHECK_MAX_MODULUS_BITS) {
254	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
255	0	*ret = DH_MODULUS_TOO_LARGE \| DH_CHECK_PUBKEY_INVALID;
256	0	return 0;
257	0	}
258
259	0	if (dh->params.q != NULL && BN_ucmp(dh->params.p, dh->params.q) < 0) {
260	0	*ret \|= DH_CHECK_INVALID_Q_VALUE \| DH_CHECK_PUBKEY_INVALID;
261	0	return 1;
262	0	}
263
264	0	return ossl_ffc_validate_public_key(&dh->params, pub_key, ret);
265	0	}
266
267		/*
268		* See SP800-56Ar3 Section 5.6.2.3.1 : FFC Partial public key validation.
269		* To only be used with ephemeral FFC public keys generated using the approved
270		* safe-prime groups.
271		*/
272		int ossl_dh_check_pub_key_partial(const DH dh, const BIGNUM pub_key, int *ret)
273	0	{
274	0	return ossl_ffc_validate_public_key_partial(&dh->params, pub_key, ret)
275	0	&& *ret == 0;
276	0	}
277
278		int ossl_dh_check_priv_key(const DH dh, const BIGNUM priv_key, int *ret)
279	0	{
280	0	int ok = 0;
281	0	BIGNUM two_powN = NULL, upper;
282
283	0	*ret = 0;
284	0	two_powN = BN_new();
285	0	if (two_powN == NULL)
286	0	return 0;
287
288	0	if (dh->params.q != NULL) {
289	0	upper = dh->params.q;
290	0	#ifndef FIPS_MODULE
291	0	} else if (dh->params.p != NULL) {
292		/*
293		* We do not have q so we just check the key is within some
294		* reasonable range, or the number of bits is equal to dh->length.
295		*/
296	0	int length = dh->length;
297
298	0	if (length == 0) {
299	0	length = BN_num_bits(dh->params.p) - 1;
300	0	if (BN_num_bits(priv_key) <= length
301	0	&& BN_num_bits(priv_key) > 1)
302	0	ok = 1;
303	0	} else if (BN_num_bits(priv_key) == length) {
304	0	ok = 1;
305	0	}
306	0	goto end;
307	0	#endif
308	0	} else {
309	0	goto end;
310	0	}
311
312		/* Is it from an approved Safe prime group ?*/
313	0	if (DH_get_nid((DH *)dh) != NID_undef && dh->length != 0) {
314	0	if (!BN_lshift(two_powN, BN_value_one(), dh->length))
315	0	goto end;
316	0	if (BN_cmp(two_powN, dh->params.q) < 0)
317	0	upper = two_powN;
318	0	}
319	0	if (!ossl_ffc_validate_private_key(upper, priv_key, ret))
320	0	goto end;
321
322	0	ok = 1;
323	0	end:
324	0	BN_free(two_powN);
325	0	return ok;
326	0	}
327
328		/*
329		* FFC pairwise check from SP800-56A R3.
330		* Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
331		*/
332		int ossl_dh_check_pairwise(const DH *dh)
333	0	{
334	0	int ret = 0;
335	0	BN_CTX *ctx = NULL;
336	0	BIGNUM *pub_key = NULL;
337
338	0	if (dh->params.p == NULL
339	0	\|\| dh->params.g == NULL
340	0	\|\| dh->priv_key == NULL
341	0	\|\| dh->pub_key == NULL)
342	0	return 0;
343
344	0	ctx = BN_CTX_new_ex(dh->libctx);
345	0	if (ctx == NULL)
346	0	goto err;
347	0	pub_key = BN_new();
348	0	if (pub_key == NULL)
349	0	goto err;
350
351		/* recalculate the public key = (g ^ priv) mod p */
352	0	if (!ossl_dh_generate_public_key(ctx, dh, dh->priv_key, pub_key))
353	0	goto err;
354		/* check it matches the existing public_key */
355	0	ret = BN_cmp(pub_key, dh->pub_key) == 0;
356	0	err:
357	0	BN_free(pub_key);
358	0	BN_CTX_free(ctx);
359	0	return ret;
360	0	}