mirror of
https://github.com/openssl/openssl.git
synced 2024-12-15 06:01:37 +08:00
63794b048c
Fixes #11864 - The dsa keygen assumed valid p, q, g values were being passed. If this is not correct then it is possible that dsa keygen can either hang or segfault. The fix was to do a partial validation of p, q, and g inside the keygen. - Fixed a potential double free in the dsa keypair test in the case when in failed (It should never fail!). It freed internal object members without setting them to NULL. - Changed the FFC key validation to accept 1024 bit keys in non fips mode. - Added tests that use both the default provider & fips provider to test these cases. Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com> (Merged from https://github.com/openssl/openssl/pull/12176)
399 lines
10 KiB
C
399 lines
10 KiB
C
/*
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* Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the Apache License 2.0 (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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/*
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* DH low level APIs are deprecated for public use, but still ok for
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* internal use.
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*/
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#include "internal/deprecated.h"
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#include <stdio.h>
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#include "internal/cryptlib.h"
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#include "dh_local.h"
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#include "crypto/bn.h"
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#include "crypto/dh.h"
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#include "crypto/security_bits.h"
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#ifdef FIPS_MODULE
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# define MIN_STRENGTH 112
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#else
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# define MIN_STRENGTH 80
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#endif
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static int generate_key(DH *dh);
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static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
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const BIGNUM *a, const BIGNUM *p,
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const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
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static int dh_init(DH *dh);
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static int dh_finish(DH *dh);
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static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
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{
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BN_CTX *ctx = NULL;
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BN_MONT_CTX *mont = NULL;
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BIGNUM *tmp;
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int ret = -1;
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#ifndef FIPS_MODULE
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int check_result;
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#endif
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if (BN_num_bits(dh->params.p) > OPENSSL_DH_MAX_MODULUS_BITS) {
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DHerr(0, DH_R_MODULUS_TOO_LARGE);
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goto err;
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}
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if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS) {
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DHerr(0, DH_R_MODULUS_TOO_SMALL);
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return 0;
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}
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ctx = BN_CTX_new_ex(dh->libctx);
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if (ctx == NULL)
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goto err;
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BN_CTX_start(ctx);
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tmp = BN_CTX_get(ctx);
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if (tmp == NULL)
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goto err;
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if (dh->priv_key == NULL) {
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DHerr(0, DH_R_NO_PRIVATE_VALUE);
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goto err;
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}
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if (dh->flags & DH_FLAG_CACHE_MONT_P) {
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mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
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dh->lock, dh->params.p, ctx);
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BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);
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if (!mont)
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goto err;
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}
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/* TODO(3.0) : Solve in a PR related to Key validation for DH */
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#ifndef FIPS_MODULE
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if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) {
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DHerr(0, DH_R_INVALID_PUBKEY);
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goto err;
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}
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#endif
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if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->params.p, ctx,
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mont)) {
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DHerr(0, ERR_R_BN_LIB);
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goto err;
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}
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ret = BN_bn2bin(tmp, key);
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err:
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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return ret;
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}
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int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
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{
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#ifdef FIPS_MODULE
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return compute_key(key, pub_key, dh);
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#else
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return dh->meth->compute_key(key, pub_key, dh);
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#endif
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}
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int DH_compute_key_padded(unsigned char *key, const BIGNUM *pub_key, DH *dh)
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{
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int rv, pad;
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#ifdef FIPS_MODULE
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rv = compute_key(key, pub_key, dh);
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#else
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rv = dh->meth->compute_key(key, pub_key, dh);
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#endif
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if (rv <= 0)
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return rv;
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pad = BN_num_bytes(dh->params.p) - rv;
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if (pad > 0) {
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memmove(key + pad, key, rv);
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memset(key, 0, pad);
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}
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return rv + pad;
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}
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static DH_METHOD dh_ossl = {
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"OpenSSL DH Method",
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generate_key,
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compute_key,
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dh_bn_mod_exp,
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dh_init,
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dh_finish,
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DH_FLAG_FIPS_METHOD,
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NULL,
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NULL
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};
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static const DH_METHOD *default_DH_method = &dh_ossl;
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const DH_METHOD *DH_OpenSSL(void)
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{
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return &dh_ossl;
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}
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const DH_METHOD *DH_get_default_method(void)
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{
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return default_DH_method;
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}
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static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
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const BIGNUM *a, const BIGNUM *p,
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const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx)
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{
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return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx);
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}
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static int dh_init(DH *dh)
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{
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dh->flags |= DH_FLAG_CACHE_MONT_P;
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ffc_params_init(&dh->params);
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dh->dirty_cnt++;
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return 1;
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}
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static int dh_finish(DH *dh)
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{
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BN_MONT_CTX_free(dh->method_mont_p);
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return 1;
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}
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#ifndef FIPS_MODULE
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void DH_set_default_method(const DH_METHOD *meth)
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{
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default_DH_method = meth;
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}
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#endif /* FIPS_MODULE */
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int DH_generate_key(DH *dh)
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{
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#ifdef FIPS_MODULE
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return generate_key(dh);
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#else
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return dh->meth->generate_key(dh);
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#endif
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}
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int dh_generate_public_key(BN_CTX *ctx, DH *dh, const BIGNUM *priv_key,
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BIGNUM *pub_key)
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{
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int ret = 0;
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BIGNUM *prk = BN_new();
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BN_MONT_CTX *mont = NULL;
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if (prk == NULL)
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return 0;
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if (dh->flags & DH_FLAG_CACHE_MONT_P) {
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mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
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dh->lock, dh->params.p, ctx);
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if (mont == NULL)
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goto err;
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}
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BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
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/* pub_key = g^priv_key mod p */
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if (!dh->meth->bn_mod_exp(dh, pub_key, dh->params.g, prk, dh->params.p,
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ctx, mont))
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goto err;
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ret = 1;
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err:
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BN_clear_free(prk);
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return ret;
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}
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static int generate_key(DH *dh)
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{
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int ok = 0;
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int generate_new_key = 0;
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#ifndef FIPS_MODULE
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unsigned l;
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#endif
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BN_CTX *ctx = NULL;
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BIGNUM *pub_key = NULL, *priv_key = NULL;
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if (BN_num_bits(dh->params.p) > OPENSSL_DH_MAX_MODULUS_BITS) {
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DHerr(0, DH_R_MODULUS_TOO_LARGE);
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return 0;
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}
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if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS) {
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DHerr(0, DH_R_MODULUS_TOO_SMALL);
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return 0;
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}
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ctx = BN_CTX_new_ex(dh->libctx);
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if (ctx == NULL)
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goto err;
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if (dh->priv_key == NULL) {
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priv_key = BN_secure_new();
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if (priv_key == NULL)
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goto err;
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generate_new_key = 1;
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} else {
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priv_key = dh->priv_key;
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}
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if (dh->pub_key == NULL) {
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pub_key = BN_new();
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if (pub_key == NULL)
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goto err;
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} else {
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pub_key = dh->pub_key;
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}
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if (generate_new_key) {
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/* Is it an approved safe prime ?*/
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if (DH_get_nid(dh) != NID_undef) {
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int max_strength =
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ifc_ffc_compute_security_bits(BN_num_bits(dh->params.p));
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if (dh->params.q == NULL
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|| dh->length > BN_num_bits(dh->params.q))
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goto err;
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/* dh->length = maximum bit length of generated private key */
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if (!ffc_generate_private_key(ctx, &dh->params, dh->length,
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max_strength, priv_key))
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goto err;
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} else {
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#ifdef FIPS_MODULE
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if (dh->params.q == NULL)
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goto err;
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#else
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if (dh->params.q == NULL) {
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/* secret exponent length */
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l = dh->length ? dh->length : BN_num_bits(dh->params.p) - 1;
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if (!BN_priv_rand_ex(priv_key, l, BN_RAND_TOP_ONE,
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BN_RAND_BOTTOM_ANY, ctx))
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goto err;
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/*
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* We handle just one known case where g is a quadratic non-residue:
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* for g = 2: p % 8 == 3
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*/
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if (BN_is_word(dh->params.g, DH_GENERATOR_2)
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&& !BN_is_bit_set(dh->params.p, 2)) {
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/* clear bit 0, since it won't be a secret anyway */
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if (!BN_clear_bit(priv_key, 0))
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goto err;
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}
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} else
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#endif
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{
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/* Do a partial check for invalid p, q, g */
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if (!ffc_params_simple_validate(dh->libctx, &dh->params,
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FFC_PARAM_TYPE_DH))
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goto err;
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/*
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* For FFC FIPS 186-4 keygen
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* security strength s = 112,
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* Max Private key size N = len(q)
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*/
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if (!ffc_generate_private_key(ctx, &dh->params,
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BN_num_bits(dh->params.q),
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MIN_STRENGTH,
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priv_key))
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goto err;
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}
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}
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}
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if (!dh_generate_public_key(ctx, dh, priv_key, pub_key))
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goto err;
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dh->pub_key = pub_key;
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dh->priv_key = priv_key;
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dh->dirty_cnt++;
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ok = 1;
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err:
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if (ok != 1)
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DHerr(0, ERR_R_BN_LIB);
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if (pub_key != dh->pub_key)
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BN_free(pub_key);
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if (priv_key != dh->priv_key)
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BN_free(priv_key);
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BN_CTX_free(ctx);
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return ok;
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}
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int dh_buf2key(DH *dh, const unsigned char *buf, size_t len)
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{
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int err_reason = DH_R_BN_ERROR;
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BIGNUM *pubkey = NULL;
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const BIGNUM *p;
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size_t p_size;
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if ((pubkey = BN_bin2bn(buf, len, NULL)) == NULL)
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goto err;
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DH_get0_pqg(dh, &p, NULL, NULL);
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if (p == NULL || (p_size = BN_num_bytes(p)) == 0) {
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err_reason = DH_R_NO_PARAMETERS_SET;
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goto err;
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}
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/*
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* As per Section 4.2.8.1 of RFC 8446 fail if DHE's
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* public key is of size not equal to size of p
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*/
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if (BN_is_zero(pubkey) || p_size != len) {
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err_reason = DH_R_INVALID_PUBKEY;
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goto err;
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}
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if (DH_set0_key(dh, pubkey, NULL) != 1)
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goto err;
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return 1;
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err:
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DHerr(DH_F_DH_BUF2KEY, err_reason);
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BN_free(pubkey);
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return 0;
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}
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size_t dh_key2buf(const DH *dh, unsigned char **pbuf_out, size_t size, int alloc)
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{
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const BIGNUM *pubkey;
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unsigned char *pbuf = NULL;
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const BIGNUM *p;
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int p_size;
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DH_get0_pqg(dh, &p, NULL, NULL);
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DH_get0_key(dh, &pubkey, NULL);
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if (p == NULL || pubkey == NULL
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|| (p_size = BN_num_bytes(p)) == 0
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|| BN_num_bytes(pubkey) == 0) {
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DHerr(DH_F_DH_KEY2BUF, DH_R_INVALID_PUBKEY);
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return 0;
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}
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if (pbuf_out != NULL && (alloc || *pbuf_out != NULL)) {
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if (!alloc) {
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if (size >= (size_t)p_size)
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pbuf = *pbuf_out;
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} else {
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pbuf = OPENSSL_malloc(p_size);
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}
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if (pbuf == NULL) {
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DHerr(DH_F_DH_KEY2BUF, ERR_R_MALLOC_FAILURE);
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return 0;
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}
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/*
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* As per Section 4.2.8.1 of RFC 8446 left pad public
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* key with zeros to the size of p
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*/
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if (BN_bn2binpad(pubkey, pbuf, p_size) < 0) {
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if (alloc)
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OPENSSL_free(pbuf);
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DHerr(DH_F_DH_KEY2BUF, DH_R_BN_ERROR);
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return 0;
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}
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*pbuf_out = pbuf;
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}
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return p_size;
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}
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