1 files changed, 159 insertions, 0 deletions
diff --git a/src/plugins/tls/openssl/qssldiffiehellmanparameters_openssl.cpp b/src/plugins/tls/openssl/qssldiffiehellmanparameters_openssl.cpp
new file mode 100644
index 0000000000..16e31e605f
--- /dev/null
+++ b/src/plugins/tls/openssl/qssldiffiehellmanparameters_openssl.cpp
@@ -0,0 +1,159 @@
+// Copyright (C) 2015 Mikkel Krautz <mikkel@krautz.dk>
+// Copyright (C) 2016 Richard J. Moore <rich@kde.org>
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#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));
+            const auto freeBuf = qScopeGuard([&] { q_OPENSSL_free(buf); });
+            if (len > 0)
+                data->assign({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