mirror of
https://github.com/openssl/openssl.git
synced 2024-12-15 06:01:37 +08:00
1c16253f3c
If |q| >= |p| then the q value is obviously wrong as q is supposed to be a prime divisor of p-1. We check if p is overly large so this added test implies that q is not large either when performing subsequent tests using that q value. Otherwise if it is too large these additional checks of the q value such as the primality test can then trigger DoS by doing overly long computations. Fixes CVE-2023-3817 Reviewed-by: Matt Caswell <matt@openssl.org> Reviewed-by: Paul Dale <pauli@openssl.org> Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com> Reviewed-by: Todd Short <todd.short@me.com> (Merged from https://github.com/openssl/openssl/pull/21550)
348 lines
9.5 KiB
C
348 lines
9.5 KiB
C
/*
|
|
* 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_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)
|
|
{
|
|
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) {
|
|
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 pubic_key */
|
|
ret = BN_cmp(pub_key, dh->pub_key) == 0;
|
|
err:
|
|
BN_free(pub_key);
|
|
BN_CTX_free(ctx);
|
|
return ret;
|
|
}
|