Add support for PSK on server side

[ChangeLog][QtNetwork][QSslSocket] TLS PSK ciphers are possible in server sockets.

Task-number: QTBUG-39077
Change-Id: Iaa854a6f50242deae5492f2e4759c727488995f5
Reviewed-by: Richard J. Moore <rich@kde.org>

9 files changed, 88 insertions, 2 deletions

diff --git a/src/network/ssl/qsslconfiguration.cpp b/src/network/ssl/qsslconfiguration.cpp
index 1fff2c31dd..1eb253d202 100644
--- a/src/network/ssl/qsslconfiguration.cpp
+++ b/src/network/ssl/qsslconfiguration.cpp
@@ -210,6 +210,7 @@ bool QSslConfiguration::operator==(const QSslConfiguration &other) const
         d->privateKey == other.d->privateKey &&
         d->sessionCipher == other.d->sessionCipher &&
         d->sessionProtocol == other.d->sessionProtocol &&
+        d->preSharedKeyIdentityHint == other.d->preSharedKeyIdentityHint &&
         d->ciphers == other.d->ciphers &&
         d->ellipticCurves == other.d->ellipticCurves &&
         d->caCertificates == other.d->caCertificates &&
@@ -260,6 +261,7 @@ bool QSslConfiguration::isNull() const
             d->sslOptions == QSslConfigurationPrivate::defaultSslOptions &&
             d->sslSession.isNull() &&
             d->sslSessionTicketLifeTimeHint == -1 &&
+            d->preSharedKeyIdentityHint.isNull() &&
             d->nextAllowedProtocols.isEmpty() &&
             d->nextNegotiatedProtocol.isNull() &&
             d->nextProtocolNegotiationStatus == QSslConfiguration::NextProtocolNegotiationNone);
@@ -810,6 +812,32 @@ QVector<QSslEllipticCurve> QSslConfiguration::supportedEllipticCurves()
 }
 
 /*!
+    \since 5.8
+
+    Returns the identity hint.
+
+    \sa setPreSharedKeyIdentityHint()
+*/
+QByteArray QSslConfiguration::preSharedKeyIdentityHint() const
+{
+    return d->preSharedKeyIdentityHint;
+}
+
+/*!
+    \since 5.8
+
+    Sets the identity hint for a preshared key authentication. This will affect the next
+    initiated handshake; calling this function on an already-encrypted socket
+    will not affect the socket's identity hint.
+
+    The identity hint is used in QSslSocket::SslServerMode only!
+*/
+void QSslConfiguration::setPreSharedKeyIdentityHint(const QByteArray &hint)
+{
+    d->preSharedKeyIdentityHint = hint;
+}
+
+/*!
   \since 5.3
 
   This function returns the protocol negotiated with the server
diff --git a/src/network/ssl/qsslconfiguration.h b/src/network/ssl/qsslconfiguration.h
index f0754d7ef5..1f39e1a06f 100644
--- a/src/network/ssl/qsslconfiguration.h
+++ b/src/network/ssl/qsslconfiguration.h
@@ -141,6 +141,9 @@ public:
     void setEllipticCurves(const QVector<QSslEllipticCurve> &curves);
     static QVector<QSslEllipticCurve> supportedEllipticCurves();
 
+    QByteArray preSharedKeyIdentityHint() const;
+    void setPreSharedKeyIdentityHint(const QByteArray &hint);
+
     static QSslConfiguration defaultConfiguration();
     static void setDefaultConfiguration(const QSslConfiguration &configuration);
 
diff --git a/src/network/ssl/qsslconfiguration_p.h b/src/network/ssl/qsslconfiguration_p.h
index 093c9d6598..113954d7d1 100644
--- a/src/network/ssl/qsslconfiguration_p.h
+++ b/src/network/ssl/qsslconfiguration_p.h
@@ -88,6 +88,7 @@ public:
           peerSessionShared(false),
           sslOptions(QSslConfigurationPrivate::defaultSslOptions),
           sslSessionTicketLifeTimeHint(-1),
+          preSharedKeyIdentityHint(),
           nextProtocolNegotiationStatus(QSslConfiguration::NextProtocolNegotiationNone)
     { }
 
@@ -121,6 +122,8 @@ public:
 
     QSslKey ephemeralServerKey;
 
+    QByteArray preSharedKeyIdentityHint;
+
     QList<QByteArray> nextAllowedProtocols;
     QByteArray nextNegotiatedProtocol;
     QSslConfiguration::NextProtocolNegotiationStatus nextProtocolNegotiationStatus;
diff --git a/src/network/ssl/qsslcontext_openssl.cpp b/src/network/ssl/qsslcontext_openssl.cpp
index b24fdad1f9..0db7e10409 100644
--- a/src/network/ssl/qsslcontext_openssl.cpp
+++ b/src/network/ssl/qsslcontext_openssl.cpp
@@ -344,6 +344,11 @@ init_context:
     }
 #endif // OPENSSL_NO_EC
 
+#ifndef OPENSSL_NO_PSK
+    if (!client)
+        q_SSL_CTX_use_psk_identity_hint(sslContext->ctx, sslContext->sslConfiguration.preSharedKeyIdentityHint().constData());
+#endif // OPENSSL_NO_PSK
+
     const QVector<QSslEllipticCurve> qcurves = sslContext->sslConfiguration.ellipticCurves();
     if (!qcurves.isEmpty()) {
 #if OPENSSL_VERSION_NUMBER >= 0x10002000L && !defined(OPENSSL_NO_EC)
diff --git a/src/network/ssl/qsslsocket.cpp b/src/network/ssl/qsslsocket.cpp
index bbc62c47ff..82df861859 100644
--- a/src/network/ssl/qsslsocket.cpp
+++ b/src/network/ssl/qsslsocket.cpp
@@ -915,6 +915,7 @@ void QSslSocket::setSslConfiguration(const QSslConfiguration &configuration)
     d->configuration.privateKey = configuration.privateKey();
     d->configuration.ciphers = configuration.ciphers();
     d->configuration.ellipticCurves = configuration.ellipticCurves();
+    d->configuration.preSharedKeyIdentityHint = configuration.preSharedKeyIdentityHint();
     d->configuration.caCertificates = configuration.caCertificates();
     d->configuration.peerVerifyDepth = configuration.peerVerifyDepth();
     d->configuration.peerVerifyMode = configuration.peerVerifyMode();
diff --git a/src/network/ssl/qsslsocket_openssl.cpp b/src/network/ssl/qsslsocket_openssl.cpp
index 5c0c8674cd..5cbd2af323 100644
--- a/src/network/ssl/qsslsocket_openssl.cpp
+++ b/src/network/ssl/qsslsocket_openssl.cpp
@@ -201,6 +201,15 @@ static unsigned int q_ssl_psk_client_callback(SSL *ssl,
     Q_ASSERT(d);
     return d->tlsPskClientCallback(hint, identity, max_identity_len, psk, max_psk_len);
 }
+
+static unsigned int q_ssl_psk_server_callback(SSL *ssl,
+                                              const char *identity,
+                                              unsigned char *psk, unsigned int max_psk_len)
+{
+    QSslSocketBackendPrivate *d = reinterpret_cast<QSslSocketBackendPrivate *>(q_SSL_get_ex_data(ssl, QSslSocketBackendPrivate::s_indexForSSLExtraData));
+    Q_ASSERT(d);
+    return d->tlsPskServerCallback(identity, psk, max_psk_len);
+}
 #endif
 } // extern "C"
 
@@ -436,8 +445,12 @@ bool QSslSocketBackendPrivate::initSslContext()
 
 #if OPENSSL_VERSION_NUMBER >= 0x10001000L && !defined(OPENSSL_NO_PSK)
     // Set the client callback for PSK
-    if (q_SSLeay() >= 0x10001000L && mode == QSslSocket::SslClientMode)
-        q_SSL_set_psk_client_callback(ssl, &q_ssl_psk_client_callback);
+    if (q_SSLeay() >= 0x10001000L) {
+        if (mode == QSslSocket::SslClientMode)
+            q_SSL_set_psk_client_callback(ssl, &q_ssl_psk_client_callback);
+        else if (mode == QSslSocket::SslServerMode)
+            q_SSL_set_psk_server_callback(ssl, &q_ssl_psk_server_callback);
+    }
 #endif
 
     return true;
@@ -1260,6 +1273,31 @@ unsigned int QSslSocketBackendPrivate::tlsPskClientCallback(const char *hint,
     return pskLength;
 }
 
+unsigned int QSslSocketBackendPrivate::tlsPskServerCallback(const char *identity,
+                                                            unsigned char *psk, unsigned int max_psk_len)
+{
+    QSslPreSharedKeyAuthenticator authenticator;
+
+    // Fill in some read-only fields (for the user)
+    authenticator.d->identityHint = configuration.preSharedKeyIdentityHint;
+    authenticator.d->identity = identity;
+    authenticator.d->maximumIdentityLength = 0; // user cannot set an identity
+    authenticator.d->maximumPreSharedKeyLength = int(max_psk_len);
+
+    // Let the client provide the remaining bits...
+    Q_Q(QSslSocket);
+    emit q->preSharedKeyAuthenticationRequired(&authenticator);
+
+    // No PSK set? Return now to make the handshake fail
+    if (authenticator.preSharedKey().isEmpty())
+        return 0;
+
+    // Copy data back into OpenSSL
+    const int pskLength = qMin(authenticator.preSharedKey().length(), authenticator.maximumPreSharedKeyLength());
+    ::memcpy(psk, authenticator.preSharedKey().constData(), pskLength);
+    return pskLength;
+}
+
 #ifdef Q_OS_WIN
 
 void QSslSocketBackendPrivate::fetchCaRootForCert(const QSslCertificate &cert)
diff --git a/src/network/ssl/qsslsocket_openssl_p.h b/src/network/ssl/qsslsocket_openssl_p.h
index 0674c05d71..c6572315f0 100644
--- a/src/network/ssl/qsslsocket_openssl_p.h
+++ b/src/network/ssl/qsslsocket_openssl_p.h
@@ -143,6 +143,7 @@ public:
     bool checkSslErrors();
     void storePeerCertificates();
     unsigned int tlsPskClientCallback(const char *hint, char *identity, unsigned int max_identity_len, unsigned char *psk, unsigned int max_psk_len);
+    unsigned int tlsPskServerCallback(const char *identity, unsigned char *psk, unsigned int max_psk_len);
 #ifdef Q_OS_WIN
     void fetchCaRootForCert(const QSslCertificate &cert);
     void _q_caRootLoaded(QSslCertificate,QSslCertificate) Q_DECL_OVERRIDE;
diff --git a/src/network/ssl/qsslsocket_openssl_symbols.cpp b/src/network/ssl/qsslsocket_openssl_symbols.cpp
index 05b7e2da7f..f625fd3e96 100644
--- a/src/network/ssl/qsslsocket_openssl_symbols.cpp
+++ b/src/network/ssl/qsslsocket_openssl_symbols.cpp
@@ -300,6 +300,8 @@ DEFINEFUNC2(void *, SSL_get_ex_data, const SSL *ssl, ssl, int idx, idx, return N
 #endif
 #if OPENSSL_VERSION_NUMBER >= 0x10001000L && !defined(OPENSSL_NO_PSK)
 DEFINEFUNC2(void, SSL_set_psk_client_callback, SSL* ssl, ssl, q_psk_client_callback_t callback, callback, return, DUMMYARG)
+DEFINEFUNC2(void, SSL_set_psk_server_callback, SSL* ssl, ssl, q_psk_server_callback_t callback, callback, return, DUMMYARG)
+DEFINEFUNC2(int, SSL_CTX_use_psk_identity_hint, SSL_CTX* ctx, ctx, const char *hint, hint, return 0, return)
 #endif
 #if OPENSSL_VERSION_NUMBER >= 0x10000000L
 #ifndef OPENSSL_NO_SSL2
@@ -901,6 +903,8 @@ bool q_resolveOpenSslSymbols()
 #endif
 #if OPENSSL_VERSION_NUMBER >= 0x10001000L && !defined(OPENSSL_NO_PSK)
     RESOLVEFUNC(SSL_set_psk_client_callback)
+    RESOLVEFUNC(SSL_set_psk_server_callback)
+    RESOLVEFUNC(SSL_CTX_use_psk_identity_hint)
 #endif
     RESOLVEFUNC(SSL_write)
 #ifndef OPENSSL_NO_SSL2
diff --git a/src/network/ssl/qsslsocket_openssl_symbols_p.h b/src/network/ssl/qsslsocket_openssl_symbols_p.h
index 5a6c934d1a..45e4380580 100644
--- a/src/network/ssl/qsslsocket_openssl_symbols_p.h
+++ b/src/network/ssl/qsslsocket_openssl_symbols_p.h
@@ -376,6 +376,9 @@ void *q_SSL_get_ex_data(const SSL *ssl, int idx);
 #ifndef OPENSSL_NO_PSK
 typedef unsigned int (*q_psk_client_callback_t)(SSL *ssl, const char *hint, char *identity, unsigned int max_identity_len, unsigned char *psk, unsigned int max_psk_len);
 void q_SSL_set_psk_client_callback(SSL *ssl, q_psk_client_callback_t callback);
+typedef unsigned int (*q_psk_server_callback_t)(SSL *ssl, const char *identity, unsigned char *psk, unsigned int max_psk_len);
+void q_SSL_set_psk_server_callback(SSL *ssl, q_psk_server_callback_t callback);
+int q_SSL_CTX_use_psk_identity_hint(SSL_CTX *ctx, const char *hint);
 #endif // OPENSSL_NO_PSK
 #if OPENSSL_VERSION_NUMBER >= 0x10000000L
 #ifndef OPENSSL_NO_SSL2