revise enclave parsing and review feedback

Author: Wraith2

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SNI/SNIPhysicalHandle.cs

@@ -87,12 +87,9 @@ private string GetStackParts()
             // trims off most of the bottom of the stack because when running under xunit there's a lot of spam
             string[] parts = Environment.StackTrace.Split(new string[] { Environment.NewLine }, StringSplitOptions.None);
             List<string> take = new List<string>(7);
-            for (int index = 0; take.Count < 7 && index < parts.Length; index++)
+            for (int index = 3; take.Count < 7 && index < parts.Length; index++)
             {
-                if (index > 2)
-                {
-                    take.Add(parts[index]);
-                }
+                take.Add(parts[index]);
             }
 
             return string.Join(Environment.NewLine, take.ToArray());

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/AlwaysEncryptedEnclaveProviderUtils.cs

@@ -18,23 +18,21 @@ public EnclavePublicKey(byte[] payload)
 
     internal class EnclaveDiffieHellmanInfo
     {
-        public int Size { get; private set; }
+        public int Size => sizeof(int) + sizeof(int) + PublicKey?.Length ?? 0 + PublicKeySignature?.Length ?? 0;
 
         public byte[] PublicKey { get; private set; }
 
         public byte[] PublicKeySignature { get; private set; }
 
-        public EnclaveDiffieHellmanInfo(byte[] payload)
+        public EnclaveDiffieHellmanInfo(byte[] payload, int offset)
         {
-            Size = payload.Length;
-
-            int publicKeySize = BitConverter.ToInt32(payload, 0);
-            int publicKeySignatureSize = BitConverter.ToInt32(payload, 4);
+            int publicKeySize = BitConverter.ToInt32(payload, offset + 0);
+            int publicKeySignatureSize = BitConverter.ToInt32(payload, offset + 4);
 
             PublicKey = new byte[publicKeySize];
             PublicKeySignature = new byte[publicKeySignatureSize];
-            Buffer.BlockCopy(payload, 8, PublicKey, 0, publicKeySize);
-            Buffer.BlockCopy(payload, 8 + publicKeySize, PublicKeySignature, 0, publicKeySignatureSize);
+            Buffer.BlockCopy(payload, offset + 8, PublicKey, 0, publicKeySize);
+            Buffer.BlockCopy(payload, offset + 8 + publicKeySize, PublicKeySignature, 0, publicKeySignatureSize);
         }
     }
 

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/AzureAttestationBasedEnclaveProvider.cs

@@ -4,6 +4,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.IdentityModel.Tokens.Jwt;
 using System.Runtime.Caching;
 using System.Security.Claims;
@@ -203,9 +204,10 @@ public AzureAttestationInfo(byte[] attestationInfo)
                     SessionId = BitConverter.ToInt64(attestationInfo, offset);
                     offset += sizeof(long);
 
-                    int secureSessionBufferSize = Convert.ToInt32(secureSessionInfoResponseSize) - sizeof(uint);
-                    byte[] secureSessionBuffer = EnclaveHelpers.TakeBytesAndAdvance(attestationInfo, ref offset, secureSessionBufferSize);
-                    EnclaveDHInfo = new EnclaveDiffieHellmanInfo(secureSessionBuffer);
+                    EnclaveDHInfo = new EnclaveDiffieHellmanInfo(attestationInfo, offset);
+                    offset += EnclaveDHInfo.Size;
+
+                    Debug.Assert(offset == attestationInfo.Length);
                 }
                 catch (Exception exception)
                 {

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/VirtualSecureModeEnclaveProvider.cs

@@ -4,6 +4,8 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
+using System.IdentityModel.Tokens.Jwt;
 using System.IO;
 using System.Net.Http;
 using System.Runtime.Serialization.Json;
@@ -150,11 +152,10 @@ public AttestationInfo(byte[] attestationInfo)
             SessionId = BitConverter.ToInt64(attestationInfo, offset);
             offset += sizeof(long);
 
-            int secureSessionBufferSize = Convert.ToInt32(secureSessionInfoResponseSize) - sizeof(uint);
-            byte[] secureSessionBuffer = EnclaveHelpers.TakeBytesAndAdvance(attestationInfo, ref offset, secureSessionBufferSize);
-
-            EnclaveDHInfo = new EnclaveDiffieHellmanInfo(secureSessionBuffer);
+            EnclaveDHInfo = new EnclaveDiffieHellmanInfo(attestationInfo, offset);
             offset += Convert.ToInt32(EnclaveDHInfo.Size);
+
+            Debug.Assert(offset == attestationInfo.Length);
         }
     }