summaryrefslogtreecommitdiffstats
path: root/src/plugins/tls/openssl/qssldiffiehellmanparameters_openssl.cpp
blob: f1cbb835d14285fedcdea14c344decf56e85d1af (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
/****************************************************************************
**
** 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 "qsslsocket_openssl_symbols_p.h"
#include "qtlsbackend_openssl_p.h"

#include <QtNetwork/private/qsslsocket_p.h>

#include <QtCore/qscopeguard.h>
#include <QtCore/qbytearray.h>
#include <QtCore/qiodevice.h>
#include <QtCore/qdebug.h>

#include <openssl/bn.h>
#include <openssl/dh.h>

QT_BEGIN_NAMESPACE

#ifndef OPENSSL_NO_DEPRECATED_3_0

namespace {

bool isSafeDH(DH *dh)
{
    int status = 0;
    int bad = 0;

    // TLSTODO: check it's needed or if supportsSsl()
    // is enough.
    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);
}

} // unnamed namespace

#endif

int QTlsBackendOpenSSL::dhParametersFromDer(const QByteArray &der, QByteArray *derData) const
{
#ifndef OPENSSL_NO_DEPRECATED_3_0
    Q_ASSERT(derData);

    if (der.isEmpty())
        return DHParams::InvalidInputDataError;

    const unsigned char *data = reinterpret_cast<const unsigned char *>(der.data());
    const int len = der.size();

    // TLSTODO: check it's needed (loading ciphers and certs in
    // addition to the library!)
    QSslSocketPrivate::ensureInitialized();

    DH *dh = q_d2i_DHparams(nullptr, &data, len);
    if (dh) {
        const auto dhRaii = qScopeGuard([dh] {q_DH_free(dh);});

        if (isSafeDH(dh))
            *derData = der;
        else
            return DHParams::UnsafeParametersError;
    } else {
        return DHParams::InvalidInputDataError;
    }
#else
    Q_UNUSED(der);
    Q_UNUSED(derData);
    qCWarning(lcTlsBackend, "Diffie-Hellman parameters are not supported, because OpenSSL v3 was built with deprecated API removed");
#endif
    return DHParams::NoError;
}

int QTlsBackendOpenSSL::dhParametersFromPem(const QByteArray &pem, QByteArray *data) const
{
#ifndef OPENSSL_NO_DEPRECATED_3_0
    Q_ASSERT(data);

    if (pem.isEmpty())
        return DHParams::InvalidInputDataError;

    // TLSTODO: check it was not a cargo-cult programming in case of
    // DH ...
    QSslSocketPrivate::ensureInitialized();

    BIO *bio = q_BIO_new_mem_buf(const_cast<char *>(pem.data()), pem.size());
    if (!bio)
        return DHParams::InvalidInputDataError;

    const auto bioRaii = qScopeGuard([bio]
    {
        q_BIO_free(bio);
    });

    DH *dh = nullptr;
    q_PEM_read_bio_DHparams(bio, &dh, nullptr, nullptr);

    if (dh) {
        const auto dhGuard = qScopeGuard([dh]
        {
            q_DH_free(dh);
        });

        if (isSafeDH(dh)) {
            char *buf = nullptr;
            const int len = q_i2d_DHparams(dh, reinterpret_cast<unsigned char **>(&buf));
            if (len > 0)
                *data = QByteArray(buf, len);
            else
                return DHParams::InvalidInputDataError;
        } else {
            return DHParams::UnsafeParametersError;
        }
    } else {
        return DHParams::InvalidInputDataError;
    }
#else
    Q_UNUSED(pem);
    Q_UNUSED(data);
    qCWarning(lcTlsBackend, "Diffie-Hellman parameters are not supported, because OpenSSL v3 was built with deprecated API removed");
#endif
    return DHParams::NoError;
}

QT_END_NAMESPACE