Fix #1529: Handle exceptions on invalid metadata signatures

ICSharpCode.Decompiler/Disassembler/ReflectionDisassembler.cs

@@ -225,19 +225,25 @@ namespace ICSharpCode.Decompiler.Disassembler
 			output.WriteLine();
 			output.Indent();
 			var declaringType = methodDefinition.GetDeclaringType();
-			var signatureProvider = new DisassemblerSignatureProvider(module, output);
-			var signature = methodDefinition.DecodeSignature(signatureProvider, genericContext);
-			if (signature.Header.HasExplicitThis) {
-				output.Write("instance explicit ");
-			} else if (signature.Header.IsInstance) {
-				output.Write("instance ");
-			}
+			MethodSignature<Action<ILNameSyntax>>? signature;
+			try {
+				var signatureProvider = new DisassemblerSignatureProvider(module, output);
+				signature = methodDefinition.DecodeSignature(signatureProvider, genericContext);
+				if (signature.Value.Header.HasExplicitThis) {
+					output.Write("instance explicit ");
+				} else if (signature.Value.Header.IsInstance) {
+					output.Write("instance ");
+				}
 
-			//call convention
-			WriteEnum(signature.Header.CallingConvention, callingConvention);
+				//call convention
+				WriteEnum(signature.Value.Header.CallingConvention, callingConvention);
 
-			//return type
-			signature.ReturnType(ILNameSyntax.Signature);
+				//return type
+				signature.Value.ReturnType(ILNameSyntax.Signature);
+			} catch (BadImageFormatException) {
+				signature = null;
+				output.Write("<bad signature>");
+			}
 			output.Write(' ');
 
 			var parameters = methodDefinition.GetParameters();
@@ -261,10 +267,10 @@ namespace ICSharpCode.Decompiler.Disassembler
 
 			//( params )
 			output.Write(" (");
-			if (signature.ParameterTypes.Length > 0) {
+			if (signature?.ParameterTypes.Length > 0) {
 				output.WriteLine();
 				output.Indent();
-				WriteParameters(metadata, parameters, signature);
+				WriteParameters(metadata, parameters, signature.Value);
 				output.Unindent();
 			}
 			output.Write(") ");

ICSharpCode.Decompiler/TypeSystem/Implementation/MetadataField.cs

@@ -178,13 +178,18 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 		{
 			var metadata = module.metadata;
 			var fieldDef = metadata.GetFieldDefinition(handle);
-			var ty = fieldDef.DecodeSignature(module.TypeProvider, new GenericContext(DeclaringType?.TypeParameters));
-			if (ty is ModifiedType mod && mod.Modifier.Name == "IsVolatile" && mod.Modifier.Namespace == "System.Runtime.CompilerServices") {
-				Volatile.Write(ref this.isVolatile, true);
-				ty = mod.ElementType;
+			IType ty;
+			try {
+				ty = fieldDef.DecodeSignature(module.TypeProvider, new GenericContext(DeclaringType?.TypeParameters));
+				if (ty is ModifiedType mod && mod.Modifier.Name == "IsVolatile" && mod.Modifier.Namespace == "System.Runtime.CompilerServices") {
+					Volatile.Write(ref this.isVolatile, true);
+					ty = mod.ElementType;
+				}
+				ty = ApplyAttributeTypeVisitor.ApplyAttributesToType(ty, Compilation,
+					fieldDef.GetCustomAttributes(), metadata, module.TypeSystemOptions);
+			} catch (BadImageFormatException) {
+				ty = SpecialType.UnknownType;
 			}
-			ty = ApplyAttributeTypeVisitor.ApplyAttributesToType(ty, Compilation,
-				fieldDef.GetCustomAttributes(), metadata, module.TypeSystemOptions);
 			return LazyInit.GetOrSet(ref this.type, ty);
 		}
 

ICSharpCode.Decompiler/TypeSystem/Implementation/MetadataMethod.cs

@@ -152,8 +152,15 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 		{
 			var methodDef = module.metadata.GetMethodDefinition(handle);
 			var genericContext = new GenericContext(DeclaringType.TypeParameters, this.TypeParameters);
-			var signature = methodDef.DecodeSignature(module.TypeProvider, genericContext);
-			var (returnType, parameters) = DecodeSignature(module, this, signature, methodDef.GetParameters());
+			IType returnType;
+			IParameter[] parameters;
+			try {
+				var signature = methodDef.DecodeSignature(module.TypeProvider, genericContext);
+				(returnType, parameters) = DecodeSignature(module, this, signature, methodDef.GetParameters());
+			} catch (BadImageFormatException) {
+				returnType = SpecialType.UnknownType;
+				parameters = Empty<IParameter>.Array;
+			}
 			LazyInit.GetOrSet(ref this.returnType, returnType);
 			LazyInit.GetOrSet(ref this.parameters, parameters);
 		}
@@ -204,10 +211,6 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 				i++;
 			}
 			Debug.Assert(i == parameters.Length);
-			bool isRefReadonly = false;
-			if (signature.ReturnType.Kind == TypeKind.ModReq && signature.ReturnType.SkipModifiers().Kind == TypeKind.ByReference) {
-				isRefReadonly = ((ModifiedType)signature.ReturnType).Modifier.IsKnownType(KnownAttribute.In);
-			}
 			var returnType = ApplyAttributeTypeVisitor.ApplyAttributesToType(signature.ReturnType,
 				module.Compilation, returnTypeAttributes, metadata, module.TypeSystemOptions);
 			return (returnType, parameters);

ICSharpCode.Decompiler/TypeSystem/Implementation/MetadataProperty.cs

@@ -16,6 +16,7 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
@@ -116,16 +117,23 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 		{
 			var propertyDef = module.metadata.GetPropertyDefinition(propertyHandle);
 			var genericContext = new GenericContext(DeclaringType.TypeParameters);
-			var signature = propertyDef.DecodeSignature(module.TypeProvider, genericContext);
-			var accessors = propertyDef.GetAccessors();
-			ParameterHandleCollection? parameterHandles;
-			if (!accessors.Getter.IsNil)
-				parameterHandles = module.metadata.GetMethodDefinition(accessors.Getter).GetParameters();
-			else if (!accessors.Setter.IsNil)
-				parameterHandles = module.metadata.GetMethodDefinition(accessors.Setter).GetParameters();
-			else
-				parameterHandles = null;
-			var (returnType, parameters) = MetadataMethod.DecodeSignature(module, this, signature, parameterHandles);
+			IType returnType;
+			IParameter[] parameters;
+			try {
+				var signature = propertyDef.DecodeSignature(module.TypeProvider, genericContext);
+				var accessors = propertyDef.GetAccessors();
+				ParameterHandleCollection? parameterHandles;
+				if (!accessors.Getter.IsNil)
+					parameterHandles = module.metadata.GetMethodDefinition(accessors.Getter).GetParameters();
+				else if (!accessors.Setter.IsNil)
+					parameterHandles = module.metadata.GetMethodDefinition(accessors.Setter).GetParameters();
+				else
+					parameterHandles = null;
+				(returnType, parameters) = MetadataMethod.DecodeSignature(module, this, signature, parameterHandles);
+			} catch (BadImageFormatException) {
+				returnType = SpecialType.UnknownType;
+				parameters = Empty<IParameter>.Array;
+			}
 			LazyInit.GetOrSet(ref this.returnType, returnType);
 			LazyInit.GetOrSet(ref this.parameters, parameters);
 		}