openssl/crypto/dsa/dsa_check.c
Tomas Mraz 85ccbab216 Check DSA parameters for excessive sizes before validating
This avoids overly long computation of various validation
checks.

Fixes CVE-2024-4603

Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/24346)
2024-05-16 15:44:40 +02:00

134 lines
3.6 KiB
C

/*
* 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
*/
/*
* DSA 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 "dsa_local.h"
#include "crypto/dsa.h"
static int dsa_precheck_params(const DSA *dsa, int *ret)
{
if (dsa->params.p == NULL || dsa->params.q == NULL) {
ERR_raise(ERR_LIB_DSA, DSA_R_BAD_FFC_PARAMETERS);
*ret = FFC_CHECK_INVALID_PQ;
return 0;
}
if (BN_num_bits(dsa->params.p) > OPENSSL_DSA_MAX_MODULUS_BITS) {
ERR_raise(ERR_LIB_DSA, DSA_R_MODULUS_TOO_LARGE);
*ret = FFC_CHECK_INVALID_PQ;
return 0;
}
if (BN_num_bits(dsa->params.q) >= BN_num_bits(dsa->params.p)) {
ERR_raise(ERR_LIB_DSA, DSA_R_BAD_Q_VALUE);
*ret = FFC_CHECK_INVALID_PQ;
return 0;
}
return 1;
}
int ossl_dsa_check_params(const DSA *dsa, int checktype, int *ret)
{
if (!dsa_precheck_params(dsa, ret))
return 0;
if (checktype == OSSL_KEYMGMT_VALIDATE_QUICK_CHECK)
return ossl_ffc_params_simple_validate(dsa->libctx, &dsa->params,
FFC_PARAM_TYPE_DSA, ret);
else
/*
* Do full FFC domain params validation according to FIPS-186-4
* - always in FIPS_MODULE
* - only if possible (i.e., seed is set) in default provider
*/
return ossl_ffc_params_full_validate(dsa->libctx, &dsa->params,
FFC_PARAM_TYPE_DSA, ret);
}
/*
* See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation.
*/
int ossl_dsa_check_pub_key(const DSA *dsa, const BIGNUM *pub_key, int *ret)
{
if (!dsa_precheck_params(dsa, ret))
return 0;
return ossl_ffc_validate_public_key(&dsa->params, pub_key, ret)
&& *ret == 0;
}
/*
* 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_dsa_check_pub_key_partial(const DSA *dsa, const BIGNUM *pub_key, int *ret)
{
if (!dsa_precheck_params(dsa, ret))
return 0;
return ossl_ffc_validate_public_key_partial(&dsa->params, pub_key, ret)
&& *ret == 0;
}
int ossl_dsa_check_priv_key(const DSA *dsa, const BIGNUM *priv_key, int *ret)
{
*ret = 0;
if (!dsa_precheck_params(dsa, ret))
return 0;
return ossl_ffc_validate_private_key(dsa->params.q, priv_key, ret);
}
/*
* FFC pairwise check from SP800-56A R3.
* Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
*/
int ossl_dsa_check_pairwise(const DSA *dsa)
{
int ret = 0;
BN_CTX *ctx = NULL;
BIGNUM *pub_key = NULL;
if (!dsa_precheck_params(dsa, &ret))
return 0;
if (dsa->params.g == NULL
|| dsa->priv_key == NULL
|| dsa->pub_key == NULL)
return 0;
ctx = BN_CTX_new_ex(dsa->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_dsa_generate_public_key(ctx, dsa, dsa->priv_key, pub_key))
goto err;
/* check it matches the existing public_key */
ret = BN_cmp(pub_key, dsa->pub_key) == 0;
err:
BN_free(pub_key);
BN_CTX_free(ctx);
return ret;
}