OpenSSL: drop support for SSLv2 and SSLv3

As per RFC 6176 (2011) and RFC 7568 (2015).

Code-wise, we're left with the decision of what to do with a few
enumerators in QSsl::Protocol; I've made TlsV1SslV3 act as TlsV1,
and adjusted the description of AnyProtocol.
A new test was introduced - deprecatedProtocol() - to test that
we, indeed, do not allow use of SSL v2 and v3. protocol() and
protocolServerSide() were reduced to exclude the (now) no-op
and meaningless tests - neither client nor server side can
start a handshake now, since we bail out early in initSslContext().

[ChangeLog][QtNetwork][SSL] Support for SSLv2 and SSLv3
sockets has been dropped, as per RFC 6176 (2011)
and RFC 7568 (2015).

Change-Id: I2fe4e8c3e82adf7aa10d4bdc9e3f7b8c299f77b6
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 11 insertions, 13 deletions

diff --git a/src/network/ssl/qsslsocket_mac.cpp b/src/network/ssl/qsslsocket_mac.cpp
index f92eaf872b..9c3c98e390 100644
--- a/src/network/ssl/qsslsocket_mac.cpp
+++ b/src/network/ssl/qsslsocket_mac.cpp
@@ -1107,6 +1107,12 @@ bool QSslSocketBackendPrivate::setSessionProtocol()
         return false;
     }
 
+    // SslV3 is unsupported.
+    if (configuration.protocol == QSsl::SslV3) {
+        qCDebug(lcSsl) << "protocol QSsl::SslV3 is disabled";
+        return false;
+    }
+
     // SecureTransport has kTLSProtocol13 constant and also, kTLSProtocolMaxSupported.
     // Calling SSLSetProtocolVersionMax/Min with any of these two constants results
     // in errInvalidParam and a failure to set the protocol version. This means
@@ -1121,14 +1127,7 @@ bool QSslSocketBackendPrivate::setSessionProtocol()
 
     OSStatus err = errSecSuccess;
 
-    if (configuration.protocol == QSsl::SslV3) {
-    #ifdef QSSLSOCKET_DEBUG
-        qCDebug(lcSsl) << plainSocket << "requesting : SSLv3";
-    #endif
-        err = SSLSetProtocolVersionMin(context, kSSLProtocol3);
-        if (err == errSecSuccess)
-            err = SSLSetProtocolVersionMax(context, kSSLProtocol3);
-    } else if (configuration.protocol == QSsl::TlsV1_0) {
+    if (configuration.protocol == QSsl::TlsV1_0) {
     #ifdef QSSLSOCKET_DEBUG
         qCDebug(lcSsl) << plainSocket << "requesting : TLSv1.0";
     #endif
@@ -1153,17 +1152,16 @@ bool QSslSocketBackendPrivate::setSessionProtocol()
     #ifdef QSSLSOCKET_DEBUG
         qCDebug(lcSsl) << plainSocket << "requesting : any";
     #endif
-        // kSSLProtocol3, since kSSLProtocol2 is disabled:
-        err = SSLSetProtocolVersionMin(context, kSSLProtocol3);
+        err = SSLSetProtocolVersionMin(context, kTLSProtocol1);
         if (err == errSecSuccess)
             err = SSLSetProtocolVersionMax(context, kTLSProtocol12);
     } else if (configuration.protocol == QSsl::TlsV1SslV3) {
     #ifdef QSSLSOCKET_DEBUG
         qCDebug(lcSsl) << plainSocket << "requesting : SSLv3 - TLSv1.2";
     #endif
-        err = SSLSetProtocolVersionMin(context, kSSLProtocol3);
+        err = SSLSetProtocolVersionMin(context, kTLSProtocol1);
         if (err == errSecSuccess)
-            err = SSLSetProtocolVersionMax(context, kTLSProtocol12);
+            err = SSLSetProtocolVersionMax(context, kTLSProtocol1);
     } else if (configuration.protocol == QSsl::SecureProtocols) {
     #ifdef QSSLSOCKET_DEBUG
         qCDebug(lcSsl) << plainSocket << "requesting : TLSv1 - TLSv1.2";
@@ -1217,7 +1215,7 @@ bool QSslSocketBackendPrivate::verifySessionProtocol() const
     if (configuration.protocol == QSsl::AnyProtocol)
         protocolOk = true;
     else if (configuration.protocol == QSsl::TlsV1SslV3)
-        protocolOk = (sessionProtocol() >= QSsl::SslV3);
+        protocolOk = (sessionProtocol() == QSsl::TlsV1_0);
     else if (configuration.protocol == QSsl::SecureProtocols)
         protocolOk = (sessionProtocol() >= QSsl::TlsV1_0);
     else if (configuration.protocol == QSsl::TlsV1_0OrLater)