Add SslProtocols property to ConfigurationOptions

MigratedBookSleeveTestSuite/Config.cs

@@ -2,6 +2,7 @@
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
+using System.Security.Authentication;
 using System.Threading.Tasks;
 using NUnit.Framework;
 using StackExchange.Redis;
@@ -187,6 +188,42 @@ public void CreateDisconnectedNonsenseConnection_DNS()
             }
         }
 
+        [Test]
+        public void SslProtocols_SingleValue()
+        {
+            var log = new StringWriter();
+            var options = ConfigurationOptions.Parse("myhost,sslProtocols=Tls11");
+            Assert.AreEqual(SslProtocols.Tls11, options.SslProtocols.Value);
+        }
+
+        [Test]
+        public void SslProtocols_MultipleValues()
+        {
+            var log = new StringWriter();
+            var options = ConfigurationOptions.Parse("myhost,sslProtocols=Tls11|Tls12");
+            Assert.AreEqual(SslProtocols.Tls11|SslProtocols.Tls12, options.SslProtocols.Value);
+        }
+
+        [Test]
+        public void SslProtocols_UsingIntegerValue()
+        {
+            var log = new StringWriter();
+
+            // The below scenario is for cases where the *targeted*
+            // .NET framework version (e.g. .NET 4.0) doesn't define an enum value (e.g. Tls11)
+            // but the OS has been patched with support
+            int integerValue = (int)(SslProtocols.Tls11 | SslProtocols.Tls12);
+            var options = ConfigurationOptions.Parse("myhost,sslProtocols=" + integerValue);
+            Assert.AreEqual(SslProtocols.Tls11 | SslProtocols.Tls12, options.SslProtocols.Value);
+        }
+
+        [Test]
+        public void SslProtocols_InvalidValue()
+        {
+            var log = new StringWriter();
+            Assert.Throws<ArgumentOutOfRangeException>(() => ConfigurationOptions.Parse("myhost,sslProtocols=InvalidSslProtocol"));            
+        }
+
         [Test]
         public void ConfigurationOptionsDefaultForAzure()
         {

StackExchange.Redis/StackExchange/Redis/ConfigurationOptions.cs

@@ -5,6 +5,7 @@
 using System.Linq;
 using System.Net;
 using System.Net.Security;
+using System.Security.Authentication;
 using System.Text;
 using System.Threading.Tasks;
 
@@ -65,7 +66,18 @@ internal static Proxy ParseProxy(string key, string value)
                 if (!Enum.TryParse(value, true, out tmp)) throw new ArgumentOutOfRangeException("Keyword '" + key + "' requires a proxy value");
                 return tmp;
             }
+#if !CORE_CLR
+            internal static SslProtocols ParseSslProtocols(string key, string value)
+            {
+                SslProtocols tmp;
+                //Flags expect commas as separators, but we need to use '|' since commas are already used in the connection string to mean something else
+                value = value?.Replace("|", ","); 
+
+                if (!Enum.TryParse(value, true, out tmp)) throw new ArgumentOutOfRangeException("Keyword '" + key + "' requires an SslProtocol value (multiple values separated by '|').");
 
+                return tmp;                
+            }
+#endif
             internal static void Unknown(string key)
             {
                 throw new ArgumentException("Keyword '" + key + "' is not supported");
@@ -78,6 +90,10 @@ internal static void Unknown(string key)
                         ConfigChannel = "configChannel", AbortOnConnectFail = "abortConnect", ResolveDns = "resolveDns",
                         ChannelPrefix = "channelPrefix", Proxy = "proxy", ConnectRetry = "connectRetry",
                         ConfigCheckSeconds = "configCheckSeconds", ResponseTimeout = "responseTimeout", DefaultDatabase = "defaultDatabase";
+#if !CORE_CLR
+            internal const string SslProtocols = "sslProtocols";
+#endif
+                
             private static readonly Dictionary<string, string> normalizedOptions = new[]
             {
                 AllowAdmin, SyncTimeout,
@@ -87,6 +103,9 @@ internal static void Unknown(string key)
                 ConfigChannel, AbortOnConnectFail, ResolveDns,
                 ChannelPrefix, Proxy, ConnectRetry,
                 ConfigCheckSeconds, DefaultDatabase,
+#if !CORE_CLR
+                SslProtocols,
+#endif
             }.ToDictionary(x => x, StringComparer.OrdinalIgnoreCase);
 
             public static string TryNormalize(string value)
@@ -156,6 +175,13 @@ public static string TryNormalize(string value)
         /// </summary>
         public bool Ssl { get { return ssl.GetValueOrDefault(); } set { ssl = value; } }
 
+
+#if !CORE_CLR
+        /// <summary>
+        /// Configures which Ssl/TLS protocols should be allowed.  If not set, defaults are chosen by the .NET framework.
+        /// </summary>
+        public SslProtocols? SslProtocols { get; set; }
+#endif
         /// <summary>
         /// Automatically encodes and decodes channels
         /// </summary>
@@ -359,6 +385,9 @@ public ConfigurationOptions Clone()
                 responseTimeout = responseTimeout,
                 defaultDatabase = defaultDatabase,
                 ReconnectRetryPolicy = reconnectRetryPolicy,
+#if !CORE_CLR
+                SslProtocols = SslProtocols,
+#endif
             };
             foreach (var item in endpoints)
                 options.endpoints.Add(item);
@@ -622,6 +651,11 @@ private void DoParse(string configuration, bool ignoreUnknown)
                         case OptionKeys.DefaultDatabase:
                             defaultDatabase = OptionKeys.ParseInt32(key, value);
                             break;
+#if !CORE_CLR
+                        case OptionKeys.SslProtocols:
+                            SslProtocols = OptionKeys.ParseSslProtocols(key, value);
+                            break;
+#endif
                         default:
                             if (!string.IsNullOrEmpty(key) && key[0] == '$')
                             {

StackExchange.Redis/StackExchange/Redis/PhysicalConnection.cs

@@ -786,7 +786,18 @@ SocketMode ISocketCallback.Connected(Stream stream, TextWriter log)
 #if CORE_CLR
                         ssl.AuthenticateAsClientAsync(host).GetAwaiter().GetResult();
 #else
+                        if (config.SslProtocols.HasValue)
+                        {
+                            var allowedProtocols = config.SslProtocols.Value;
+                            ssl.AuthenticateAsClient(host, new X509CertificateCollection(), allowedProtocols, checkCertificateRevocation: true);
+                        }
+                        else
+                        {
+                            // default to defaults for the .NET framework
                             ssl.AuthenticateAsClient(host);
+                        }
+
+                        Multiplexer.LogLocked(log, $"SSL connection established successfully using protocol: {ssl.SslProtocol}");
 #endif
                     }
                     catch (AuthenticationException authexception)