JsonWebTokenHandler to return the JsonWebToken on validation failure

src/Microsoft.IdentityModel.JsonWebTokens/JsonWebTokenHandler.cs

@@ -1319,7 +1319,8 @@ private TokenValidationResult ValidateJWS(JsonWebToken jsonWebToken, TokenValida
                 return new TokenValidationResult
                 {
                     Exception = ex,
-                    IsValid = false
+                    IsValid = false,
+                    TokenOnFailedValidation = validationParameters.IncludeTokenOnFailedValidation ? jsonWebToken : null
                 };
             }
         }
@@ -1354,7 +1355,8 @@ private TokenValidationResult ValidateJWE(JsonWebToken jwtToken, TokenValidation
                 return new TokenValidationResult
                 {
                     Exception = ex,
-                    IsValid = false
+                    IsValid = false,
+                    TokenOnFailedValidation = validationParameters.IncludeTokenOnFailedValidation ? jwtToken : null
                 };
             }
         }

src/Microsoft.IdentityModel.Tokens/TokenValidationParameters.cs

@@ -211,6 +211,7 @@ protected TokenValidationParameters(TokenValidationParameters other)
             ConfigurationManager = other.ConfigurationManager;
             CryptoProviderFactory = other.CryptoProviderFactory;
             DebugId = other.DebugId;
+            IncludeTokenOnFailedValidation = other.IncludeTokenOnFailedValidation;
             IgnoreTrailingSlashWhenValidatingAudience = other.IgnoreTrailingSlashWhenValidatingAudience;
             IssuerSigningKey = other.IssuerSigningKey;
             IssuerSigningKeyResolver = other.IssuerSigningKeyResolver;
@@ -427,6 +428,10 @@ public virtual ClaimsIdentity CreateClaimsIdentity(SecurityToken securityToken,
         [DefaultValue(true)]
         public bool IgnoreTrailingSlashWhenValidatingAudience { get; set; } = true;
 
+        /// <summary>
+        /// Gets or sets the flag that indicates whether to include the <see cref="SecurityToken"/> when the validation fails.
+        /// </summary>
+        public bool IncludeTokenOnFailedValidation { get; set; } = false;
 
         /// <summary>
         /// Gets or sets a delegate for validating the <see cref="SecurityKey"/> that signed the token.

src/Microsoft.IdentityModel.Tokens/TokenValidationResult.cs

@@ -142,6 +142,11 @@ public bool IsValid
         /// </summary>
         public SecurityToken SecurityToken { get; set; }
 
+        /// <summary>
+        /// The <see cref="SecurityToken"/> to be returned when validation fails.
+        /// </summary>
+        public SecurityToken TokenOnFailedValidation { get; internal set; }
+
         /// <summary>
         /// Gets or sets the <see cref="CallContext"/> that contains call information.
         /// </summary>

test/Microsoft.IdentityModel.JsonWebTokens.Tests/JsonWebTokenHandlerTests.cs

@@ -3358,6 +3358,77 @@ public static TheoryData<CreateTokenTheoryData> SecurityKeyNotFoundExceptionTest
                 },
             };
         }
+
+        [Theory, MemberData(nameof(IncludeSecurityTokenOnFailureTestTheoryData))]
+        public void IncludeSecurityTokenOnFailedValidationTest(CreateTokenTheoryData theoryData)
+        {
+            var context = TestUtilities.WriteHeader($"{this}.IncludeSecurityTokenOnFailedValidationTest", theoryData);
+
+            try
+            {
+                var handler = new JsonWebTokenHandler();
+                var token = handler.CreateToken(theoryData.TokenDescriptor);
+                var validationResult = handler.ValidateToken(token, theoryData.ValidationParameters);
+                if (theoryData.ValidationParameters.IncludeTokenOnFailedValidation)
+                {
+                    Assert.NotNull(validationResult.TokenOnFailedValidation);
+                }
+                else
+                {
+                    Assert.Null(validationResult.TokenOnFailedValidation);
+                }
+            }
+            catch (Exception ex)
+            {
+                theoryData.ExpectedException.ProcessException(ex, context);
+            }
+
+            TestUtilities.AssertFailIfErrors(context);
+        }
+
+        public static TheoryData<CreateTokenTheoryData> IncludeSecurityTokenOnFailureTestTheoryData()
+        {
+            return new TheoryData<CreateTokenTheoryData>()
+            {
+                new CreateTokenTheoryData
+                {
+                    First = true,
+                    TestId = "TokenExpiredIncludeTokenOnFailedValidation",
+                    TokenDescriptor = new SecurityTokenDescriptor
+                    {
+                        Subject = new ClaimsIdentity(Default.PayloadClaimsExpired),
+                        Expires = DateTime.UtcNow.Subtract(new TimeSpan(0, 10, 0)),
+                        IssuedAt = DateTime.UtcNow.Subtract(new TimeSpan(1, 0, 0)),
+                        NotBefore = DateTime.UtcNow.Subtract(new TimeSpan(1, 0, 0)),
+                        SigningCredentials = Default.AsymmetricSigningCredentials,
+                    },
+                    ValidationParameters = new TokenValidationParameters
+                    {
+                        IssuerSigningKey = Default.SymmetricSigningKey,
+                        ValidIssuer = Default.Issuer,
+                        IncludeTokenOnFailedValidation = true
+                    }
+                },
+                new CreateTokenTheoryData
+                {
+                    First = true,
+                    TestId = "TokenExpiredNotIncludeTokenOnFailedValidation",
+                    TokenDescriptor = new SecurityTokenDescriptor
+                    {
+                        Subject = new ClaimsIdentity(Default.PayloadClaimsExpired),
+                        Expires = DateTime.UtcNow.Subtract(new TimeSpan(0, 10, 0)),
+                        IssuedAt = DateTime.UtcNow.Subtract(new TimeSpan(1, 0, 0)),
+                        NotBefore = DateTime.UtcNow.Subtract(new TimeSpan(1, 0, 0)),
+                        SigningCredentials = Default.AsymmetricSigningCredentials,
+                    },
+                    ValidationParameters = new TokenValidationParameters
+                    {
+                        IssuerSigningKey = Default.SymmetricSigningKey,
+                        ValidIssuer = Default.Issuer,
+                    }
+                },
+            };
+        }
     }
 
     public class CreateTokenTheoryData : TheoryDataBase

test/Microsoft.IdentityModel.Tokens.Tests/TokenValidationParametersTests.cs

@@ -16,14 +16,16 @@ namespace Microsoft.IdentityModel.Tokens.Tests
 {
     public class TokenValidationParametersTests
     {
+        int ExpectedPropertyCount = 57;
+
         [Fact]
         public void Publics()
         {
             TokenValidationParameters validationParameters = new TokenValidationParameters();
             Type type = typeof(TokenValidationParameters);
             PropertyInfo[] properties = type.GetProperties();
-            if (properties.Length != 56)
-                Assert.True(false, "Number of properties has changed from 56 to: " + properties.Length + ", adjust tests");
+            if (properties.Length != ExpectedPropertyCount)
+                Assert.True(false, $"Number of properties has changed from {ExpectedPropertyCount} to: " + properties.Length + ", adjust tests");
 
             TokenValidationParameters actorValidationParameters = new TokenValidationParameters();
             SecurityKey issuerSigningKey = KeyingMaterial.DefaultX509Key_2048_Public;
@@ -157,8 +159,8 @@ public void GetSets()
             TokenValidationParameters validationParameters = new TokenValidationParameters();
             Type type = typeof(TokenValidationParameters);
             PropertyInfo[] properties = type.GetProperties();
-            if (properties.Length != 56)
-                Assert.True(false, "Number of public fields has changed from 56 to: " + properties.Length + ", adjust tests");
+            if (properties.Length != ExpectedPropertyCount)
+                Assert.True(false, $"Number of public fields has changed from {ExpectedPropertyCount} to: " + properties.Length + ", adjust tests");
 
             GetSetContext context =
                 new GetSetContext

test/Microsoft.IdentityModel.Tokens.Tests/TokenValidationResultTests.cs

@@ -21,8 +21,8 @@ public void GetSets()
             TokenValidationResult tokenValidationResult = new TokenValidationResult();
             Type type = typeof(TokenValidationResult);
             PropertyInfo[] properties = type.GetProperties();
-            if (properties.Length != 9)
-                Assert.True(false, "Number of public fields has changed from 9 to: " + properties.Length + ", adjust tests");
+            if (properties.Length != 10)
+                Assert.True(false, "Number of public fields has changed from 10 to: " + properties.Length + ", adjust tests");
 
             GetSetContext context =
                 new GetSetContext