Algorithm validation: Remove exceptions (#2719)

* Remove throws when validating algorithm used for signing a token.

* Adding small commits into one

* Remove the use of delegate check and move to ValidationParameters

* Replaced .Any() method call from check

---------

Co-authored-by: Franco Fung <francofung@microsoft.com>

src/Microsoft.IdentityModel.JsonWebTokens/JwtRegisteredClaimNames.cs

@@ -29,6 +29,11 @@ public struct JwtRegisteredClaimNames
         /// </summary>
         public const string Address = "address";
 
+        /// <summary>
+        /// See: <see href="https://datatracker.ietf.org/doc/html/rfc7519#section-4"/>.
+        /// </summary>
+        public const string Alg = "alg";
+
         /// <summary>
         /// See: <see href="https://openid.net/specs/openid-connect-core-1_0.html#IDToken"/>.
         /// </summary>

src/Microsoft.IdentityModel.Tokens/Validation/AlgorithmValidationResult.cs

@@ -0,0 +1,70 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+#nullable enable
+namespace Microsoft.IdentityModel.Tokens
+{
+    /// <summary>
+    /// Contains the result of validating the Algorithm of a <see cref="SecurityToken"/>.
+    /// The <see cref="TokenValidationResult"/> contains a collection of <see cref="ValidationResult"/> for each step in the token validation.
+    /// </summary>
+    internal class AlgorithmValidationResult : ValidationResult
+    {
+        private Exception? _exception;
+        private const string TokenSource = "Microsoft.IdentityModel.Tokens";
+
+        /// <summary>
+        /// Creates an instance of <see cref="AlgorithmValidationResult"/>.
+        /// </summary>
+        /// <paramref name="algorithm"/>The algorithm to be validated.
+        public AlgorithmValidationResult(string? algorithm)
+            : base(ValidationFailureType.ValidationSucceeded)
+        {
+            Algorithm = algorithm;
+            IsValid = true;
+        }
+
+        /// <summary>
+        /// Creates an instance of <see cref=" AlgorithmValidationResult"/>
+        /// </summary>
+        /// <paramref name="algorithm"/>The algorithm to be validated.
+        /// <paramref name="validationFailure"/> is the <see cref="ValidationFailureType"/> that occurred during validation.
+        /// <paramref name="exceptionDetail"/> is the <see cref="ExceptionDetail"/> that occurred during validation.
+        public AlgorithmValidationResult(string? algorithm, ValidationFailureType validationFailure, ExceptionDetail exceptionDetail)
+            : base(validationFailure, exceptionDetail)
+        {
+            Algorithm = algorithm;
+            IsValid = false;
+        }
+
+        /// <summary>
+        /// Gets the <see cref="Exception"/> that occurred during validation.
+        /// </summary>
+        public override Exception? Exception
+        {
+            get
+            {
+                if (_exception != null || ExceptionDetail == null)
+                    return _exception;
+
+                HasValidOrExceptionWasRead = true;
+                _exception = ExceptionDetail.GetException();
+                if (_exception is SecurityTokenInvalidAlgorithmException securityTokenInvalidAlgorithmException)
+                {
+                    securityTokenInvalidAlgorithmException.InvalidAlgorithm = Algorithm;
+                    securityTokenInvalidAlgorithmException.Source = TokenSource;
+                }
+
+                return _exception;
+            }
+        }
+
+        /// <summary>
+        /// Gets the algorithm used to sign the token.
+        /// </summary>
+        public string? Algorithm { get; }
+
+    }
+}
+#nullable restore

src/Microsoft.IdentityModel.Tokens/Validation/ValidationFailureType.cs

@@ -33,6 +33,12 @@ private class NullArgumentFailure : ValidationFailureType { internal NullArgumen
         public static readonly ValidationFailureType IssuerValidationFailed = new IssuerValidationFailure("IssuerValidationFailed");
         private class IssuerValidationFailure : ValidationFailureType { internal IssuerValidationFailure(string name) : base(name) { } }
 
+        /// <summary>
+        /// Defines a type that represents an algorithm validation failed.
+        /// </summary>
+        public static readonly ValidationFailureType AlgorithmValidationFailed = new AlgorithmValidationFailure("AlgorithmValidationFailed");
+        private class AlgorithmValidationFailure : ValidationFailureType { internal AlgorithmValidationFailure(string name) : base(name) { } }
+
         /// <summary>
         /// Defines a type that represents that audience validation failed.
         /// </summary>

src/Microsoft.IdentityModel.Tokens/Validation/ValidationParameters.cs

@@ -476,7 +476,7 @@ public string RoleClaimType
         /// If set to a non-empty collection, only the algorithms listed will be considered valid.
         /// The default is <c>null</c>.
         /// </remarks>
-        public IList<string> ValidAlgorithms { get; }
+        public IList<string> ValidAlgorithms { get; set; }
 
         /// <summary>
         /// Gets the <see cref="IList{String}"/> that contains valid audiences that will be used to check against the token's audience.

src/Microsoft.IdentityModel.Tokens/Validation/Validators.Algorithm.cs

@@ -2,12 +2,60 @@
 // Licensed under the MIT License.
 
 using System;
+using System.Diagnostics;
 using System.Linq;
 using Microsoft.IdentityModel.Logging;
 
+#nullable enable
 namespace Microsoft.IdentityModel.Tokens
 {
     public static partial class Validators
     {
+        /// <summary>
+        /// Validates a given algorithm for a <see cref="SecurityKey"/>.
+        /// </summary>
+        /// <param name="algorithm">The algorithm to be validated.</param>
+        /// <param name="securityKey">The <see cref="SecurityKey"/> that signed the <see cref="SecurityToken"/>.</param>
+        /// <param name="securityToken">The <see cref="SecurityToken"/> being validated.</param>
+        /// <param name="validationParameters"><see cref="TokenValidationParameters"/> required for validation.</param>
+        /// <param name="callContext"></param>
+#pragma warning disable CA1801 // TODO: remove pragma disable once callContext is used for logging
+        internal static AlgorithmValidationResult ValidateAlgorithm(
+            string algorithm,
+            SecurityKey securityKey,
+            SecurityToken securityToken,
+            ValidationParameters validationParameters,
+            CallContext callContext)
+#pragma warning restore CA1801 // TODO: remove pragma disable once callContext is used for logging
+        {
+            if (validationParameters == null)
+            {
+                return new AlgorithmValidationResult(
+                    algorithm,
+                    ValidationFailureType.NullArgument,
+                    new ExceptionDetail(
+                        new MessageDetail(
+                            LogMessages.IDX10000,
+                            LogHelper.MarkAsNonPII(nameof(validationParameters))),
+                        typeof(ArgumentNullException),
+                        new StackFrame(true)));
+            }
+
+            if (validationParameters.ValidAlgorithms != null && validationParameters.ValidAlgorithms.Count > 0 && !validationParameters.ValidAlgorithms.Contains(algorithm, StringComparer.Ordinal))
+            {
+                return new AlgorithmValidationResult(
+                    algorithm,
+                    ValidationFailureType.AlgorithmValidationFailed,
+                    new ExceptionDetail(
+                        new MessageDetail(
+                            LogMessages.IDX10696,
+                            LogHelper.MarkAsNonPII(algorithm)),
+                        typeof(SecurityTokenInvalidAlgorithmException),
+                        new StackFrame(true)));
+            }
+
+            return new AlgorithmValidationResult(algorithm);
+        }
     }
 }
+#nullable restore

src/System.IdentityModel.Tokens.Jwt/JwtRegisteredClaimNames.cs

@@ -23,6 +23,11 @@ public struct JwtRegisteredClaimNames
         /// </summary>
         public const string Acr = Microsoft.IdentityModel.JsonWebTokens.JwtRegisteredClaimNames.Acr;
 
+        /// <summary>
+        /// https://datatracker.ietf.org/doc/html/rfc7519#section-4
+        /// </summary>
+        public const string Alg = Microsoft.IdentityModel.JsonWebTokens.JwtRegisteredClaimNames.Alg;
+
         /// <summary>
         /// http://openid.net/specs/openid-connect-core-1_0.html#IDToken
         /// </summary>

test/Microsoft.IdentityModel.TestUtils/ExpectedException.cs

@@ -255,6 +255,11 @@ public static ExpectedException SecurityTokenKeyWrapException(string substringEx
             return new ExpectedException(typeof(SecurityTokenKeyWrapException), substringExpected, innerTypeExpected, propertiesExpected: propertiesExpected);
         }
 
+        public static ExpectedException SecurityTokenInvalidAlgorithmException(string substringExpected = null, Type innerTypeExpected = null, Dictionary<string, object> propertiesExpected = null)
+        {
+            return new ExpectedException(typeof(SecurityTokenInvalidAlgorithmException), substringExpected, innerTypeExpected, propertiesExpected: propertiesExpected);
+        }
+
         public static ExpectedException SecurityTokenInvalidLifetimeException(string substringExpected = null, Type innerTypeExpected = null, Dictionary<string, object> propertiesExpected = null)
         {
             return new ExpectedException(typeof(SecurityTokenInvalidLifetimeException), substringExpected, innerTypeExpected, propertiesExpected: propertiesExpected);

test/Microsoft.IdentityModel.TestUtils/IdentityComparer.cs

@@ -19,7 +19,6 @@
 using System.Security.Cryptography;
 using System.Security.Cryptography.X509Certificates;
 using System.Text.Json;
-using System.Xml.Linq;
 using Microsoft.IdentityModel.JsonWebTokens;
 using Microsoft.IdentityModel.Protocols;
 using Microsoft.IdentityModel.Protocols.OpenIdConnect;
@@ -157,6 +156,73 @@ public class IdentityComparer
             };
 
         // Keep methods in alphabetical order
+
+        public static bool AreAlgorithmValidationResultsEqual(object object1, object object2, CompareContext context)
+        {
+            var localContext = new CompareContext(context);
+            if (!ContinueCheckingEquality(object1, object2, context))
+                return context.Merge(localContext);
+
+            return AreAlgorithmValidationResultsEqual(
+                object1 as AlgorithmValidationResult,
+                object2 as AlgorithmValidationResult,
+                "AlgorithmValidationResult1",
+                "AlgorithmValidationResult2",
+                null,
+                context);
+        }
+
+        internal static bool AreAlgorithmValidationResultsEqual(
+            AlgorithmValidationResult algorithmValidationResult1,
+            AlgorithmValidationResult algorithmValidationResult2,
+            string name1,
+            string name2,
+            string stackPrefix,
+            CompareContext context)
+        {
+            var localContext = new CompareContext(context);
+            if (!ContinueCheckingEquality(algorithmValidationResult1, algorithmValidationResult2, localContext))
+                return context.Merge(localContext);
+
+            if (algorithmValidationResult1.Algorithm != algorithmValidationResult2.Algorithm)
+                localContext.Diffs.Add($"AlgorithmValidationResult1.Algorithm: '{algorithmValidationResult1.Algorithm}' != AlgorithmValidationResult2.Algorithm: '{algorithmValidationResult2.Algorithm}'");
+
+            if (algorithmValidationResult1.IsValid != algorithmValidationResult2.IsValid)
+                localContext.Diffs.Add($"AlgorithmValidationResult1.IsValid: {algorithmValidationResult1.IsValid} != AlgorithmValidationResult2.IsValid: {algorithmValidationResult2.IsValid}");
+
+            if (algorithmValidationResult1.ValidationFailureType != algorithmValidationResult2.ValidationFailureType)
+                localContext.Diffs.Add($"AlgorithmValidationResult1.ValidationFailureType: {algorithmValidationResult1.ValidationFailureType} != AlgorithmValidationResult2.ValidationFailureType: {algorithmValidationResult2.ValidationFailureType}");
+
+            // true => both are not null.
+            if (ContinueCheckingEquality(algorithmValidationResult1.Exception, algorithmValidationResult2.Exception, localContext))
+            {
+                AreStringsEqual(
+                    algorithmValidationResult1.Exception.Message,
+                    algorithmValidationResult2.Exception.Message,
+                    $"({name1}).Exception.Message",
+                    $"({name2}).Exception.Message",
+                    localContext);
+
+                AreStringsEqual(
+                    algorithmValidationResult1.Exception.Source,
+                    algorithmValidationResult2.Exception.Source,
+                    $"({name1}).Exception.Source",
+                    $"({name2}).Exception.Source",
+                    localContext);
+
+                if (!string.IsNullOrEmpty(stackPrefix))
+                    AreStringPrefixesEqual(
+                        algorithmValidationResult1.Exception.StackTrace.Trim(),
+                        algorithmValidationResult2.Exception.StackTrace.Trim(),
+                        $"({name1}).Exception.StackTrace",
+                        $"({name2}).Exception.StackTrace",
+                        stackPrefix.Trim(),
+                        localContext);
+            }
+
+            return context.Merge(localContext);
+        }
+
         public static bool AreBoolsEqual(object object1, object object2, CompareContext context)
         {
             return AreBoolsEqual(object1, object2, "bool1", "bool2", context);
@@ -903,7 +969,7 @@ internal static bool AreTokenTypeValidationResultsEqual(
                 return context.Merge(localContext);
 
             if (tokenTypeValidationResult1.Type != tokenTypeValidationResult2.Type)
-                localContext.Diffs.Add($"TokenTypeValidationResult1.Type: '{tokenTypeValidationResult1.Type}' != TokenTypeValidationResult2.ExpirationTime: '{tokenTypeValidationResult2.Type}'");
+                localContext.Diffs.Add($"TokenTypeValidationResult1.Type: '{tokenTypeValidationResult1.Type}' != TokenTypeValidationResult2.Type: '{tokenTypeValidationResult2.Type}'");
 
             if (tokenTypeValidationResult1.IsValid != tokenTypeValidationResult2.IsValid)
                 localContext.Diffs.Add($"TokenTypeValidationResult1.IsValid: {tokenTypeValidationResult1.IsValid} != TokenTypeValidationResult2.IsValid: {tokenTypeValidationResult2.IsValid}");
@@ -1817,6 +1883,5 @@ public static bool AreDatesEqualWithEpsilon(DateTime? dateTime1, DateTime? dateT
 
             return dateTime1 == dateTime2;
         }
-
     }
 }