From bd26defd9bdddf8619a8d6ce1c6cb90b28c27d88 Mon Sep 17 00:00:00 2001
From: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Date: Wed, 15 Oct 2014 15:13:47 +0200
Subject: QSslSocket: introduce support for TLS PSK (client side)

[ChangeLog][QtNetwork][QSslSocket] It is now possible to use TLS PSK
ciphersuites in client sockets.

Task-number: QTBUG-39077
Change-Id: I5523a2be33d46230c6f4106c322fab8a5afa37b4
Reviewed-by: Richard J. Moore <rich@kde.org>
---
 src/network/ssl/qsslsocket_openssl.cpp | 68 ++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

(limited to 'src/network/ssl/qsslsocket_openssl.cpp')

diff --git a/src/network/ssl/qsslsocket_openssl.cpp b/src/network/ssl/qsslsocket_openssl.cpp
index bf348f6f9f..509db38672 100644
--- a/src/network/ssl/qsslsocket_openssl.cpp
+++ b/src/network/ssl/qsslsocket_openssl.cpp
@@ -58,6 +58,8 @@
 #include "qsslcipher_p.h"
 #include "qsslkey_p.h"
 #include "qsslellipticcurve.h"
+#include "qsslpresharedkeyauthenticator.h"
+#include "qsslpresharedkeyauthenticator_p.h"
 
 #include <QtCore/qdatetime.h>
 #include <QtCore/qdebug.h>
@@ -72,6 +74,8 @@
 #include <QtCore/qvarlengtharray.h>
 #include <QLibrary> // for loading the security lib for the CA store
 
+#include <string.h>
+
 QT_BEGIN_NAMESPACE
 
 #if defined(Q_OS_MACX)
@@ -89,6 +93,10 @@ bool QSslSocketPrivate::s_libraryLoaded = false;
 bool QSslSocketPrivate::s_loadedCiphersAndCerts = false;
 bool QSslSocketPrivate::s_loadRootCertsOnDemand = false;
 
+#if OPENSSL_VERSION_NUMBER >= 0x10001000L
+int QSslSocketBackendPrivate::s_indexForSSLExtraData = -1;
+#endif
+
 /* \internal
 
     From OpenSSL's thread(3) manual page:
@@ -181,6 +189,18 @@ static unsigned long id_function()
 {
     return (quintptr)QThread::currentThreadId();
 }
+
+#if OPENSSL_VERSION_NUMBER >= 0x10001000L && !defined(OPENSSL_NO_PSK)
+static unsigned int q_ssl_psk_client_callback(SSL *ssl,
+                                              const char *hint,
+                                              char *identity, unsigned int max_identity_len,
+                                              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->tlsPskClientCallback(hint, identity, max_identity_len, psk, max_psk_len);
+}
+#endif
 } // extern "C"
 
 QSslSocketBackendPrivate::QSslSocketBackendPrivate()
@@ -390,6 +410,18 @@ bool QSslSocketBackendPrivate::initSslContext()
     else
         q_SSL_set_accept_state(ssl);
 
+#if OPENSSL_VERSION_NUMBER >= 0x10001000L
+    // Save a pointer to this object into the SSL structure.
+    if (q_SSLeay() >= 0x10001000L)
+        q_SSL_set_ex_data(ssl, s_indexForSSLExtraData, this);
+#endif
+
+#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);
+#endif
+
     return true;
 }
 
@@ -443,6 +475,11 @@ bool QSslSocketPrivate::ensureLibraryLoaded()
         q_SSL_load_error_strings();
         q_OpenSSL_add_all_algorithms();
 
+#if OPENSSL_VERSION_NUMBER >= 0x10001000L
+        if (q_SSLeay() >= 0x10001000L)
+            QSslSocketBackendPrivate::s_indexForSSLExtraData = q_SSL_get_ex_new_index(0L, NULL, NULL, NULL, NULL);
+#endif
+
         // Initialize OpenSSL's random seed.
         if (!q_RAND_status()) {
             struct {
@@ -1262,6 +1299,37 @@ bool QSslSocketBackendPrivate::checkSslErrors()
     return true;
 }
 
+unsigned int QSslSocketBackendPrivate::tlsPskClientCallback(const char *hint,
+                                                            char *identity, unsigned int max_identity_len,
+                                                            unsigned char *psk, unsigned int max_psk_len)
+{
+    QSslPreSharedKeyAuthenticator authenticator;
+
+    // Fill in some read-only fields (for the user)
+    if (hint)
+        authenticator.d->identityHint = QByteArray::fromRawData(hint, int(::strlen(hint))); // it's NUL terminated, but do not include the NUL
+
+    authenticator.d->maximumIdentityLength = int(max_identity_len) - 1; // needs to be NUL terminated
+    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 identityLength = qMin(authenticator.identity().length(), authenticator.maximumIdentityLength());
+    ::memcpy(identity, authenticator.identity().constData(), identityLength);
+    identity[identityLength] = 0;
+
+    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)
-- 
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