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

Source
/*
 * Copyright 1995-2025 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 <openssl/self_test.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;
    /*
     * A DH with no modulus or generator cannot be checked.  Report
     * the failure via |*ret| rather than dereferencing NULL below.
     */
    if (dh->params.p == NULL || dh->params.g == NULL) {
        *ret = DH_NOT_SUITABLE_GENERATOR | DH_CHECK_P_NOT_PRIME;
        return 1;
    }
    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;
    /* A DH with no modulus or generator cannot be checked. */
    if (dh->params.p == NULL || dh->params.g == NULL) {
        *ret = DH_NOT_SUITABLE_GENERATOR | DH_CHECK_P_NOT_PRIME;
        return 1;
    }
    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)
{
    *ret = 0;
    /*
     * Without a modulus we cannot check anything; signal failure via
     * |*ret| rather than crashing in BN_num_bits below.
     */
    if (dh->params.p == NULL) {
        *ret = DH_CHECK_PUBKEY_INVALID;
        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_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 return_on_null_numbers)
{
    int ret = 0;
    BN_CTX *ctx = NULL;
    BIGNUM *pub_key = NULL;
    OSSL_SELF_TEST *st = NULL;
    OSSL_CALLBACK *stcb = NULL;
    void *stcbarg = NULL;

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

    OSSL_SELF_TEST_get_callback(dh->libctx, &stcb, &stcbarg);
    st = OSSL_SELF_TEST_new(stcb, stcbarg);
    if (st == NULL)
        goto err;
    OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT,
        OSSL_SELF_TEST_DESC_PCT_DH);

    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;

#ifdef FIPS_MODULE
    {
        int len;
        unsigned char bytes[1024] = { 0 }; /* Max key size of 8192 bits */

        if (BN_num_bytes(pub_key) > (int)sizeof(bytes))
            goto err;
        len = BN_bn2bin(pub_key, bytes);
        OSSL_SELF_TEST_oncorrupt_byte(st, bytes);
        if (BN_bin2bn(bytes, len, pub_key) == NULL)
            goto err;
    }
#endif
    /* 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);

    OSSL_SELF_TEST_onend(st, ret);
    OSSL_SELF_TEST_free(st);
    return ret;
}

Coverage Report

Created: 2026-06-19 06:39

Line	Count	Source
1		/*
2		* Copyright 1995-2025 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 <openssl/self_test.h>
20		#include "dh_local.h"
21		#include "crypto/dh.h"
22
23		/*-
24		* Check that p and g are suitable enough
25		*
26		* p is odd
27		* 1 < g < p - 1
28		*/
29		int DH_check_params_ex(const DH *dh)
30	0	{
31	0	int errflags = 0;
32
33	0	if (!DH_check_params(dh, &errflags))
34	0	return 0;
35
36	0	if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
37	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_PRIME);
38	0	if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
39	0	ERR_raise(ERR_LIB_DH, DH_R_NOT_SUITABLE_GENERATOR);
40	0	if ((errflags & DH_MODULUS_TOO_SMALL) != 0)
41	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL);
42	0	if ((errflags & DH_MODULUS_TOO_LARGE) != 0)
43	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
44
45	0	return errflags == 0;
46	0	}
47
48		#ifdef FIPS_MODULE
49		int DH_check_params(const DH dh, int ret)
50		{
51		int nid;
52
53		*ret = 0;
54		/*
55		* SP800-56A R3 Section 5.5.2 Assurances of Domain Parameter Validity
56		* (1a) The domain parameters correspond to any approved safe prime group.
57		*/
58		nid = DH_get_nid((DH *)dh);
59		if (nid != NID_undef)
60		return 1;
61		/*
62		* OR
63		* (2b) FFC domain params conform to FIPS-186-4 explicit domain param
64		* validity tests.
65		*/
66		return ossl_ffc_params_FIPS186_4_validate(dh->libctx, &dh->params,
67		FFC_PARAM_TYPE_DH, ret, NULL);
68		}
69		#else
70		int DH_check_params(const DH dh, int ret)
71	0	{
72	0	int ok = 0;
73	0	BIGNUM *tmp = NULL;
74	0	BN_CTX *ctx = NULL;
75
76	0	*ret = 0;
77		/*
78		* A DH with no modulus or generator cannot be checked. Report
79		* the failure via \|*ret\| rather than dereferencing NULL below.
80		*/
81	0	if (dh->params.p == NULL \|\| dh->params.g == NULL) {
82	0	*ret = DH_NOT_SUITABLE_GENERATOR \| DH_CHECK_P_NOT_PRIME;
83	0	return 1;
84	0	}
85	0	ctx = BN_CTX_new_ex(dh->libctx);
86	0	if (ctx == NULL)
87	0	goto err;
88	0	BN_CTX_start(ctx);
89	0	tmp = BN_CTX_get(ctx);
90	0	if (tmp == NULL)
91	0	goto err;
92
93	0	if (!BN_is_odd(dh->params.p))
94	0	*ret \|= DH_CHECK_P_NOT_PRIME;
95	0	if (BN_is_negative(dh->params.g)
96	0	\|\| BN_is_zero(dh->params.g)
97	0	\|\| BN_is_one(dh->params.g))
98	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
99	0	if (BN_copy(tmp, dh->params.p) == NULL \|\| !BN_sub_word(tmp, 1))
100	0	goto err;
101	0	if (BN_cmp(dh->params.g, tmp) >= 0)
102	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
103	0	if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS)
104	0	*ret \|= DH_MODULUS_TOO_SMALL;
105	0	if (BN_num_bits(dh->params.p) > OPENSSL_DH_MAX_MODULUS_BITS)
106	0	*ret \|= DH_MODULUS_TOO_LARGE;
107
108	0	ok = 1;
109	0	err:
110	0	BN_CTX_end(ctx);
111	0	BN_CTX_free(ctx);
112	0	return ok;
113	0	}
114		#endif /* FIPS_MODULE */
115
116		/*-
117		* Check that p is a safe prime and
118		* g is a suitable generator.
119		*/
120		int DH_check_ex(const DH *dh)
121	0	{
122	0	int errflags = 0;
123
124	0	if (!DH_check(dh, &errflags))
125	0	return 0;
126
127	0	if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
128	0	ERR_raise(ERR_LIB_DH, DH_R_NOT_SUITABLE_GENERATOR);
129	0	if ((errflags & DH_CHECK_Q_NOT_PRIME) != 0)
130	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_Q_NOT_PRIME);
131	0	if ((errflags & DH_CHECK_INVALID_Q_VALUE) != 0)
132	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_INVALID_Q_VALUE);
133	0	if ((errflags & DH_CHECK_INVALID_J_VALUE) != 0)
134	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_INVALID_J_VALUE);
135	0	if ((errflags & DH_UNABLE_TO_CHECK_GENERATOR) != 0)
136	0	ERR_raise(ERR_LIB_DH, DH_R_UNABLE_TO_CHECK_GENERATOR);
137	0	if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
138	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_PRIME);
139	0	if ((errflags & DH_CHECK_P_NOT_SAFE_PRIME) != 0)
140	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_SAFE_PRIME);
141	0	if ((errflags & DH_MODULUS_TOO_SMALL) != 0)
142	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL);
143	0	if ((errflags & DH_MODULUS_TOO_LARGE) != 0)
144	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
145
146	0	return errflags == 0;
147	0	}
148
149		/* Note: according to documentation - this only checks the params */
150		int DH_check(const DH dh, int ret)
151	0	{
152		#ifdef FIPS_MODULE
153		return DH_check_params(dh, ret);
154		#else
155	0	int ok = 0, r, q_good = 0;
156	0	BN_CTX *ctx = NULL;
157	0	BIGNUM t1 = NULL, t2 = NULL;
158	0	int nid = DH_get_nid((DH *)dh);
159
160	0	*ret = 0;
161		/* A DH with no modulus or generator cannot be checked. */
162	0	if (dh->params.p == NULL \|\| dh->params.g == NULL) {
163	0	*ret = DH_NOT_SUITABLE_GENERATOR \| DH_CHECK_P_NOT_PRIME;
164	0	return 1;
165	0	}
166	0	if (nid != NID_undef)
167	0	return 1;
168
169		/* Don't do any checks at all with an excessively large modulus */
170	0	if (BN_num_bits(dh->params.p) > OPENSSL_DH_CHECK_MAX_MODULUS_BITS) {
171	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
172	0	*ret = DH_MODULUS_TOO_LARGE \| DH_CHECK_P_NOT_PRIME;
173	0	return 0;
174	0	}
175
176	0	if (!DH_check_params(dh, ret))
177	0	return 0;
178
179	0	ctx = BN_CTX_new_ex(dh->libctx);
180	0	if (ctx == NULL)
181	0	goto err;
182	0	BN_CTX_start(ctx);
183	0	t1 = BN_CTX_get(ctx);
184	0	t2 = BN_CTX_get(ctx);
185	0	if (t2 == NULL)
186	0	goto err;
187
188	0	if (dh->params.q != NULL) {
189	0	if (BN_ucmp(dh->params.p, dh->params.q) > 0)
190	0	q_good = 1;
191	0	else
192	0	*ret \|= DH_CHECK_INVALID_Q_VALUE;
193	0	}
194
195	0	if (q_good) {
196	0	if (BN_cmp(dh->params.g, BN_value_one()) <= 0)
197	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
198	0	else if (BN_cmp(dh->params.g, dh->params.p) >= 0)
199	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
200	0	else {
201		/* Check g^q == 1 mod p */
202	0	if (!BN_mod_exp(t1, dh->params.g, dh->params.q, dh->params.p, ctx))
203	0	goto err;
204	0	if (!BN_is_one(t1))
205	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
206	0	}
207	0	r = BN_check_prime(dh->params.q, ctx, NULL);
208	0	if (r < 0)
209	0	goto err;
210	0	if (!r)
211	0	*ret \|= DH_CHECK_Q_NOT_PRIME;
212		/* Check p == 1 mod q i.e. q divides p - 1 */
213	0	if (!BN_div(t1, t2, dh->params.p, dh->params.q, ctx))
214	0	goto err;
215	0	if (!BN_is_one(t2))
216	0	*ret \|= DH_CHECK_INVALID_Q_VALUE;
217	0	if (dh->params.j != NULL
218	0	&& BN_cmp(dh->params.j, t1))
219	0	*ret \|= DH_CHECK_INVALID_J_VALUE;
220	0	}
221
222	0	r = BN_check_prime(dh->params.p, ctx, NULL);
223	0	if (r < 0)
224	0	goto err;
225	0	if (!r)
226	0	*ret \|= DH_CHECK_P_NOT_PRIME;
227	0	else if (dh->params.q == NULL) {
228	0	if (!BN_rshift1(t1, dh->params.p))
229	0	goto err;
230	0	r = BN_check_prime(t1, ctx, NULL);
231	0	if (r < 0)
232	0	goto err;
233	0	if (!r)
234	0	*ret \|= DH_CHECK_P_NOT_SAFE_PRIME;
235	0	}
236	0	ok = 1;
237	0	err:
238	0	BN_CTX_end(ctx);
239	0	BN_CTX_free(ctx);
240	0	return ok;
241	0	#endif /* FIPS_MODULE */
242	0	}
243
244		int DH_check_pub_key_ex(const DH dh, const BIGNUM pub_key)
245	0	{
246	0	int errflags = 0;
247
248	0	if (!DH_check_pub_key(dh, pub_key, &errflags))
249	0	return 0;
250
251	0	if ((errflags & DH_CHECK_PUBKEY_TOO_SMALL) != 0)
252	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_TOO_SMALL);
253	0	if ((errflags & DH_CHECK_PUBKEY_TOO_LARGE) != 0)
254	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_TOO_LARGE);
255	0	if ((errflags & DH_CHECK_PUBKEY_INVALID) != 0)
256	0	ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_INVALID);
257
258	0	return errflags == 0;
259	0	}
260
261		/*
262		* See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation.
263		*/
264		int DH_check_pub_key(const DH dh, const BIGNUM pub_key, int *ret)
265	0	{
266	0	*ret = 0;
267		/*
268		* Without a modulus we cannot check anything; signal failure via
269		* \|*ret\| rather than crashing in BN_num_bits below.
270		*/
271	0	if (dh->params.p == NULL) {
272	0	*ret = DH_CHECK_PUBKEY_INVALID;
273	0	return 1;
274	0	}
275		/* Don't do any checks at all with an excessively large modulus */
276	0	if (BN_num_bits(dh->params.p) > OPENSSL_DH_CHECK_MAX_MODULUS_BITS) {
277	0	ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
278	0	*ret = DH_MODULUS_TOO_LARGE \| DH_CHECK_PUBKEY_INVALID;
279	0	return 0;
280	0	}
281
282	0	if (dh->params.q != NULL && BN_ucmp(dh->params.p, dh->params.q) < 0) {
283	0	*ret \|= DH_CHECK_INVALID_Q_VALUE \| DH_CHECK_PUBKEY_INVALID;
284	0	return 1;
285	0	}
286
287	0	return ossl_ffc_validate_public_key(&dh->params, pub_key, ret);
288	0	}
289
290		/*
291		* See SP800-56Ar3 Section 5.6.2.3.1 : FFC Partial public key validation.
292		* To only be used with ephemeral FFC public keys generated using the approved
293		* safe-prime groups.
294		*/
295		int ossl_dh_check_pub_key_partial(const DH dh, const BIGNUM pub_key, int *ret)
296	0	{
297	0	return ossl_ffc_validate_public_key_partial(&dh->params, pub_key, ret)
298	0	&& *ret == 0;
299	0	}
300
301		int ossl_dh_check_priv_key(const DH dh, const BIGNUM priv_key, int *ret)
302	0	{
303	0	int ok = 0;
304	0	BIGNUM two_powN = NULL, upper;
305
306	0	*ret = 0;
307	0	two_powN = BN_new();
308	0	if (two_powN == NULL)
309	0	return 0;
310
311	0	if (dh->params.q != NULL) {
312	0	upper = dh->params.q;
313	0	#ifndef FIPS_MODULE
314	0	} else if (dh->params.p != NULL) {
315		/*
316		* We do not have q so we just check the key is within some
317		* reasonable range, or the number of bits is equal to dh->length.
318		*/
319	0	int length = dh->length;
320
321	0	if (length == 0) {
322	0	length = BN_num_bits(dh->params.p) - 1;
323	0	if (BN_num_bits(priv_key) <= length
324	0	&& BN_num_bits(priv_key) > 1)
325	0	ok = 1;
326	0	} else if (BN_num_bits(priv_key) == length) {
327	0	ok = 1;
328	0	}
329	0	goto end;
330	0	#endif
331	0	} else {
332	0	goto end;
333	0	}
334
335		/* Is it from an approved Safe prime group ?*/
336	0	if (DH_get_nid((DH *)dh) != NID_undef && dh->length != 0) {
337	0	if (!BN_lshift(two_powN, BN_value_one(), dh->length))
338	0	goto end;
339	0	if (BN_cmp(two_powN, dh->params.q) < 0)
340	0	upper = two_powN;
341	0	}
342	0	if (!ossl_ffc_validate_private_key(upper, priv_key, ret))
343	0	goto end;
344
345	0	ok = 1;
346	0	end:
347	0	BN_free(two_powN);
348	0	return ok;
349	0	}
350
351		/*
352		* FFC pairwise check from SP800-56A R3.
353		* Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
354		*/
355		int ossl_dh_check_pairwise(const DH *dh, int return_on_null_numbers)
356	0	{
357	0	int ret = 0;
358	0	BN_CTX *ctx = NULL;
359	0	BIGNUM *pub_key = NULL;
360	0	OSSL_SELF_TEST *st = NULL;
361	0	OSSL_CALLBACK *stcb = NULL;
362	0	void *stcbarg = NULL;
363
364	0	if (dh->params.p == NULL
365	0	\|\| dh->params.g == NULL
366	0	\|\| dh->priv_key == NULL
367	0	\|\| dh->pub_key == NULL)
368	0	return return_on_null_numbers;
369
370	0	OSSL_SELF_TEST_get_callback(dh->libctx, &stcb, &stcbarg);
371	0	st = OSSL_SELF_TEST_new(stcb, stcbarg);
372	0	if (st == NULL)
373	0	goto err;
374	0	OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT,
375	0	OSSL_SELF_TEST_DESC_PCT_DH);
376
377	0	ctx = BN_CTX_new_ex(dh->libctx);
378	0	if (ctx == NULL)
379	0	goto err;
380	0	pub_key = BN_new();
381	0	if (pub_key == NULL)
382	0	goto err;
383
384		/* recalculate the public key = (g ^ priv) mod p */
385	0	if (!ossl_dh_generate_public_key(ctx, dh, dh->priv_key, pub_key))
386	0	goto err;
387
388		#ifdef FIPS_MODULE
389		{
390		int len;
391		unsigned char bytes[1024] = { 0 }; /* Max key size of 8192 bits */
392
393		if (BN_num_bytes(pub_key) > (int)sizeof(bytes))
394		goto err;
395		len = BN_bn2bin(pub_key, bytes);
396		OSSL_SELF_TEST_oncorrupt_byte(st, bytes);
397		if (BN_bin2bn(bytes, len, pub_key) == NULL)
398		goto err;
399		}
400		#endif
401		/* check it matches the existing public_key */
402	0	ret = BN_cmp(pub_key, dh->pub_key) == 0;
403	0	err:
404	0	BN_free(pub_key);
405	0	BN_CTX_free(ctx);
406
407	0	OSSL_SELF_TEST_onend(st, ret);
408	0	OSSL_SELF_TEST_free(st);
409	0	return ret;
410	0	}