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/****************************************************************************
**
** Copyright (C) 2015 Mikkel Krautz <mikkel@krautz.dk>
** Copyright (C) 2016 Richard J. Moore <rich@kde.org>
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtNetwork module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qssldiffiehellmanparameters.h"
#include "qssldiffiehellmanparameters_p.h"
#include "qsslsocket_openssl_symbols_p.h"
#include "qsslsocket.h"
#include "qsslsocket_p.h"
#include "private/qssl_p.h"
#include <QtCore/qatomic.h>
#include <QtCore/qbytearray.h>
#include <QtCore/qiodevice.h>
#include <QtCore/qscopeguard.h>
#ifndef QT_NO_DEBUG_STREAM
#include <QtCore/qdebug.h>
#endif
#include <openssl/bn.h>
#include <openssl/dh.h>
QT_BEGIN_NAMESPACE
#ifdef OPENSSL_NO_DEPRECATED_3_0
static int q_DH_check(DH *dh, int *status)
{
// DH_check was first deprecated in OpenSSL 3.0.0, as low-level
// API; the EVP_PKEY family of functions was advised as an alternative.
// As of now EVP_PKEY_params_check ends up calling ... DH_check,
// which is good enough.
Q_ASSERT(dh);
Q_ASSERT(status);
EVP_PKEY *key = q_EVP_PKEY_new();
if (!key) {
qCWarning(lcSsl, "EVP_PKEY_new failed");
QSslSocketBackendPrivate::logAndClearErrorQueue();
return 0;
}
const auto keyDeleter = qScopeGuard([key](){
q_EVP_PKEY_free(key);
});
if (!q_EVP_PKEY_set1_DH(key, dh)) {
qCWarning(lcSsl, "EVP_PKEY_set1_DH failed");
QSslSocketBackendPrivate::logAndClearErrorQueue();
return 0;
}
EVP_PKEY_CTX *keyCtx = q_EVP_PKEY_CTX_new(key, nullptr);
if (!keyCtx) {
qCWarning(lcSsl, "EVP_PKEY_CTX_new failed");
QSslSocketBackendPrivate::logAndClearErrorQueue();
return 0;
}
const auto ctxDeleter = qScopeGuard([keyCtx]{
q_EVP_PKEY_CTX_free(keyCtx);
});
const int result = q_EVP_PKEY_param_check(keyCtx);
QSslSocketBackendPrivate::logAndClearErrorQueue();
// Note: unlike DH_check, we cannot obtain the 'status',
// if the 'result' is 0 (actually the result is 1 only
// if this 'status' was 0). We could probably check the
// errors from the error queue, but it's not needed anyway
// - see the 'isSafeDH' below, how it returns immediately
// on 0.
Q_UNUSED(status);
return result;
}
#endif // OPENSSL_NO_DEPRECATED_3_0
static bool isSafeDH(DH *dh)
{
int status = 0;
int bad = 0;
QSslSocketPrivate::ensureInitialized();
// From https://wiki.openssl.org/index.php/Diffie-Hellman_parameters:
//
// The additional call to BN_mod_word(dh->p, 24)
// (and unmasking of DH_NOT_SUITABLE_GENERATOR)
// is performed to ensure your program accepts
// IETF group parameters. OpenSSL checks the prime
// is congruent to 11 when g = 2; while the IETF's
// primes are congruent to 23 when g = 2.
// Without the test, the IETF parameters would
// fail validation. For details, see Diffie-Hellman
// Parameter Check (when g = 2, must p mod 24 == 11?).
// Mark p < 1024 bits as unsafe.
if (q_DH_bits(dh) < 1024)
return false;
if (q_DH_check(dh, &status) != 1)
return false;
const BIGNUM *p = nullptr;
const BIGNUM *q = nullptr;
const BIGNUM *g = nullptr;
q_DH_get0_pqg(dh, &p, &q, &g);
if (q_BN_is_word(const_cast<BIGNUM *>(g), DH_GENERATOR_2)) {
const unsigned long residue = q_BN_mod_word(p, 24);
if (residue == 11 || residue == 23)
status &= ~DH_NOT_SUITABLE_GENERATOR;
}
bad |= DH_CHECK_P_NOT_PRIME;
bad |= DH_CHECK_P_NOT_SAFE_PRIME;
bad |= DH_NOT_SUITABLE_GENERATOR;
return !(status & bad);
}
void QSslDiffieHellmanParametersPrivate::decodeDer(const QByteArray &der)
{
if (der.isEmpty()) {
error = QSslDiffieHellmanParameters::InvalidInputDataError;
return;
}
const unsigned char *data = reinterpret_cast<const unsigned char *>(der.data());
int len = der.size();
QSslSocketPrivate::ensureInitialized();
DH *dh = q_d2i_DHparams(nullptr, &data, len);
if (dh) {
if (isSafeDH(dh))
derData = der;
else
error = QSslDiffieHellmanParameters::UnsafeParametersError;
} else {
error = QSslDiffieHellmanParameters::InvalidInputDataError;
}
q_DH_free(dh);
}
void QSslDiffieHellmanParametersPrivate::decodePem(const QByteArray &pem)
{
if (pem.isEmpty()) {
error = QSslDiffieHellmanParameters::InvalidInputDataError;
return;
}
if (!QSslSocket::supportsSsl()) {
error = QSslDiffieHellmanParameters::InvalidInputDataError;
return;
}
QSslSocketPrivate::ensureInitialized();
BIO *bio = q_BIO_new_mem_buf(const_cast<char *>(pem.data()), pem.size());
if (!bio) {
error = QSslDiffieHellmanParameters::InvalidInputDataError;
return;
}
DH *dh = nullptr;
q_PEM_read_bio_DHparams(bio, &dh, nullptr, nullptr);
if (dh) {
if (isSafeDH(dh)) {
char *buf = nullptr;
int len = q_i2d_DHparams(dh, reinterpret_cast<unsigned char **>(&buf));
if (len > 0)
derData = QByteArray(buf, len);
else
error = QSslDiffieHellmanParameters::InvalidInputDataError;
} else {
error = QSslDiffieHellmanParameters::UnsafeParametersError;
}
} else {
error = QSslDiffieHellmanParameters::InvalidInputDataError;
}
q_DH_free(dh);
q_BIO_free(bio);
}
QT_END_NAMESPACE
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