From 68c795fe81277f73aeb90d8ad4c6f4305f32c906 Mon Sep 17 00:00:00 2001
From: Peter Dettman <peter.dettman@bouncycastle.org>
Date: Mon, 12 Jul 2021 15:15:36 +0700
Subject: Port of new TLS API from bc-java

---
 crypto/src/tls/ClientHello.cs | 167 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 167 insertions(+)
 create mode 100644 crypto/src/tls/ClientHello.cs

(limited to 'crypto/src/tls/ClientHello.cs')

diff --git a/crypto/src/tls/ClientHello.cs b/crypto/src/tls/ClientHello.cs
new file mode 100644
index 000000000..50a33ac39
--- /dev/null
+++ b/crypto/src/tls/ClientHello.cs
@@ -0,0 +1,167 @@
+using System;
+using System.Collections;
+using System.IO;
+
+using Org.BouncyCastle.Utilities;
+using Org.BouncyCastle.Utilities.IO;
+
+namespace Org.BouncyCastle.Tls
+{
+    public sealed class ClientHello
+    {
+        private readonly ProtocolVersion m_version;
+        private readonly byte[] m_random;
+        private readonly byte[] m_sessionID;
+        private readonly byte[] m_cookie;
+        private readonly int[] m_cipherSuites;
+        private readonly IDictionary m_extensions;
+
+        public ClientHello(ProtocolVersion version, byte[] random, byte[] sessionID, byte[] cookie,
+            int[] cipherSuites, IDictionary extensions)
+        {
+            this.m_version = version;
+            this.m_random = random;
+            this.m_sessionID = sessionID;
+            this.m_cookie = cookie;
+            this.m_cipherSuites = cipherSuites;
+            this.m_extensions = extensions;
+        }
+
+        public int[] CipherSuites
+        {
+            get { return m_cipherSuites; }
+        }
+
+        public byte[] Cookie
+        {
+            get { return m_cookie; }
+        }
+
+        public IDictionary Extensions
+        {
+            get { return m_extensions; }
+        }
+
+        public byte[] Random
+        {
+            get { return m_random; }
+        }
+
+        public byte[] SessionID
+        {
+            get { return m_sessionID; }
+        }
+
+        public ProtocolVersion Version
+        {
+            get { return m_version; }
+        }
+
+        /// <summary>Encode this <see cref="ClientHello"/> to a <see cref="Stream"/>.</summary>
+        /// <param name="context">the <see cref="TlsContext"/> of the current connection.</param>
+        /// <param name="output">the <see cref="Stream"/> to encode to.</param>
+        /// <exception cref="IOException"/>
+        public void Encode(TlsContext context, Stream output)
+        {
+            TlsUtilities.WriteVersion(m_version, output);
+
+            output.Write(m_random, 0, m_random.Length);
+
+            TlsUtilities.WriteOpaque8(m_sessionID, output);
+
+            if (null != m_cookie)
+            {
+                TlsUtilities.WriteOpaque8(m_cookie, output);
+            }
+
+            TlsUtilities.WriteUint16ArrayWithUint16Length(m_cipherSuites, output);
+
+            TlsUtilities.WriteUint8ArrayWithUint8Length(new short[]{ CompressionMethod.cls_null }, output);
+
+            TlsProtocol.WriteExtensions(output, m_extensions);
+        }
+
+        /// <summary>Parse a <see cref="ClientHello"/> from a <see cref="MemoryStream"/>.</summary>
+        /// <param name="messageInput">the <see cref="MemoryStream"/> to parse from.</param>
+        /// <param name="dtlsOutput">for DTLS this should be non-null; the input is copied to this
+        /// <see cref="Stream"/>, minus the cookie field.</param>
+        /// <returns>a <see cref="ClientHello"/> object.</returns>
+        /// <exception cref="TlsFatalAlert"/>
+        public static ClientHello Parse(MemoryStream messageInput, Stream dtlsOutput)
+        {
+            try
+            {
+                return ImplParse(messageInput, dtlsOutput);
+            }
+            catch (TlsFatalAlert e)
+            {
+                throw e;
+            }
+            catch (IOException e)
+            {
+                throw new TlsFatalAlert(AlertDescription.decode_error, e);
+            }
+        }
+
+        /// <exception cref="IOException"/>
+        private static ClientHello ImplParse(MemoryStream messageInput, Stream dtlsOutput)
+        {
+            Stream input = messageInput;
+            if (null != dtlsOutput)
+            {
+                input = new TeeInputStream(input, dtlsOutput);
+            }
+
+            ProtocolVersion clientVersion = TlsUtilities.ReadVersion(input);
+
+            byte[] random = TlsUtilities.ReadFully(32, input);
+
+            byte[] sessionID = TlsUtilities.ReadOpaque8(input, 0, 32);
+
+            byte[] cookie = null;
+            if (null != dtlsOutput)
+            {
+                /*
+                 * RFC 6347 This specification increases the cookie size limit to 255 bytes for greater
+                 * future flexibility. The limit remains 32 for previous versions of DTLS.
+                 */
+                int maxCookieLength = ProtocolVersion.DTLSv12.IsEqualOrEarlierVersionOf(clientVersion) ? 255 : 32;
+
+                cookie = TlsUtilities.ReadOpaque8(messageInput, 0, maxCookieLength);
+            }
+
+            int cipher_suites_length = TlsUtilities.ReadUint16(input);
+            if (cipher_suites_length < 2 || (cipher_suites_length & 1) != 0
+                || (int)(messageInput.Length - messageInput.Position) < cipher_suites_length)
+            {
+                throw new TlsFatalAlert(AlertDescription.decode_error);
+            }
+
+            /*
+             * NOTE: "If the session_id field is not empty (implying a session resumption request) this
+             * vector must include at least the cipher_suite from that session."
+             */
+            int[] cipherSuites = TlsUtilities.ReadUint16Array(cipher_suites_length / 2, input);
+
+            short[] compressionMethods = TlsUtilities.ReadUint8ArrayWithUint8Length(input, 1);
+            if (!Arrays.Contains(compressionMethods, CompressionMethod.cls_null))
+                throw new TlsFatalAlert(AlertDescription.handshake_failure);
+
+            /*
+             * NOTE: Can't use TlsProtocol.ReadExtensions directly because TeeInputStream a) won't have
+             * 'Length' or 'Position' properties in the FIPS provider, b) isn't a MemoryStream.
+             */
+            IDictionary extensions = null;
+            if (messageInput.Position < messageInput.Length)
+            {
+                byte[] extBytes = TlsUtilities.ReadOpaque16(input);
+
+                TlsProtocol.AssertEmpty(messageInput);
+
+                extensions = TlsProtocol.ReadExtensionsDataClientHello(extBytes);
+            }
+
+            return new ClientHello(clientVersion, random, sessionID, cookie, cipherSuites, extensions);
+        }
+    }
+}
-- 
cgit 1.4.1