crypto/dh/dh_check.c - third_party/openssl - Git at Google

 /*
  * Copyright 1995-2021 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();
     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;
     BN_CTX *ctx = NULL;
     BIGNUM *t1 = NULL, *t2 = NULL;
     int nid = DH_get_nid((DH *)dh);

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

     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->params.q != NULL) {
         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)
 {
     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);
 }

 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)
         goto err;
     upper = dh->params.q;

     /* 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 err;
         if (BN_cmp(two_powN, dh->params.q) < 0)
             upper = two_powN;
     }
     if (!ossl_ffc_validate_private_key(upper, priv_key, ret))
         goto err;

     ok = 1;
 err:
     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 pubic_key */
     ret = BN_cmp(pub_key, dh->pub_key) == 0;
 err:
     BN_free(pub_key);
     BN_CTX_free(ctx);
     return ret;
 }
	/*
	* Copyright 1995-2021 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();
	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;
	BN_CTX *ctx = NULL;
	BIGNUM t1 = NULL, t2 = NULL;
	int nid = DH_get_nid((DH *)dh);

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

	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->params.q != NULL) {
	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)
	{
	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);
	}

	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)
	goto err;
	upper = dh->params.q;

	/* 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 err;
	if (BN_cmp(two_powN, dh->params.q) < 0)
	upper = two_powN;
	}
	if (!ossl_ffc_validate_private_key(upper, priv_key, ret))
	goto err;

	ok = 1;
	err:
	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 pubic_key */
	ret = BN_cmp(pub_key, dh->pub_key) == 0;
	err:
	BN_free(pub_key);
	BN_CTX_free(ctx);
	return ret;
	}