AssemblyEvidenceFactory.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Security / Policy / AssemblyEvidenceFactory.cs / 1305376 / AssemblyEvidenceFactory.cs
                        
                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
// [....]
// 
 
using System;
using System.Collections.Generic; 
using System.Diagnostics.Contracts;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices; 
using System.Security;
using System.Security.Permissions; 
using Microsoft.Win32.SafeHandles; 

namespace System.Security.Policy 
{

    /// 
    ///     Factory class which can create evidence on demand for an assembly 
    /// 
    internal sealed class AssemblyEvidenceFactory : IRuntimeEvidenceFactory 
    { 
        private PEFileEvidenceFactory m_peFileFactory;
        private RuntimeAssembly m_targetAssembly; 

        /// 
        ///     Create a factory which can generate evidence for the specified assembly
        ///  
        private AssemblyEvidenceFactory(RuntimeAssembly targetAssembly, PEFileEvidenceFactory peFileFactory)
        { 
            Contract.Assert(targetAssembly != null); 
            Contract.Assert(peFileFactory != null);
 
            m_targetAssembly = targetAssembly;
            m_peFileFactory = peFileFactory;
        }
 
        /// 
        ///     PEFile that the assembly is loaded from 
        ///  
        internal SafePEFileHandle PEFile
        { 
            [SecurityCritical]
            get { return m_peFileFactory.PEFile; }
        }
 
        /// 
        ///     Assembly that the evidence generated is for 
        ///  
        public IEvidenceFactory Target
        { 
            get { return m_targetAssembly; }
        }

        ///  
        ///     Generate a specific type of evidence for this assembly
        ///  
        public EvidenceBase GenerateEvidence(Type evidenceType) 
        {
            // Assembly evidence is a superset of the evidence that a PEFile can supply, so first see if the 
            // requested evidence type can be generated by the assembly's PEFile
            EvidenceBase evidence = m_peFileFactory.GenerateEvidence(evidenceType);
            if (evidence != null)
            { 
                return evidence;
            } 
 
            // If the PEFile didn't know about this type of evidence, see if it is an evidence type that the
            // Assembly knows how to generate 
            if (evidenceType == typeof(GacInstalled))
            {
                return GenerateGacEvidence();
            } 
            else if (evidenceType == typeof(Hash))
            { 
                return GenerateHashEvidence(); 
            }
#pragma warning disable 618 // We need to generate PermissionRequestEvidence in compatibility mode 
            else if (evidenceType == typeof(PermissionRequestEvidence))
            {
                return GeneratePermissionRequestEvidence();
            } 
#pragma warning restore 618
            else if (evidenceType == typeof(StrongName)) 
            { 
                return GenerateStrongNameEvidence();
            } 

            return null;
        }
 
        /// 
        ///     Generate evidence if the assembly is installed in the GAC 
        ///  
        private GacInstalled GenerateGacEvidence()
        { 
            if (!m_targetAssembly.GlobalAssemblyCache)
            {
                return null;
            } 

            m_peFileFactory.FireEvidenceGeneratedEvent(EvidenceTypeGenerated.Gac); 
            return new GacInstalled(); 
        }
 
        /// 
        ///     Generate evidence for the assembly's hash value
        /// 
        private Hash GenerateHashEvidence() 
        {
            if (m_targetAssembly.IsDynamic) 
            { 
                return null;
            } 

            m_peFileFactory.FireEvidenceGeneratedEvent(EvidenceTypeGenerated.Hash);
            return new Hash(m_targetAssembly);
        } 

#pragma warning disable 618 // We need to generate PermissionRequestEvidence in compatibility mode 
        ///  
        ///     Generate evidence for the assembly's declarative security
        ///  
        [SecuritySafeCritical]
        private PermissionRequestEvidence GeneratePermissionRequestEvidence()
        {
            Contract.Assert(AppDomain.CurrentDomain.IsLegacyCasPolicyEnabled); 

            PermissionSet minimumPermissions = null; 
            PermissionSet optionalPermissions = null; 
            PermissionSet refusedPermissions = null;
 
            GetAssemblyPermissionRequests(m_targetAssembly.GetNativeHandle(),
                                          JitHelpers.GetObjectHandleOnStack(ref minimumPermissions),
                                          JitHelpers.GetObjectHandleOnStack(ref optionalPermissions),
                                          JitHelpers.GetObjectHandleOnStack(ref refusedPermissions)); 

            if (minimumPermissions != null || optionalPermissions != null || refusedPermissions != null) 
            { 
                return new PermissionRequestEvidence(minimumPermissions,
                                                     optionalPermissions, 
                                                     refusedPermissions);
            }

            return null; 
        }
#pragma warning restore 618 
 
        /// 
        ///     Generate evidence for this file's strong name 
        /// 
        [SecuritySafeCritical]
        private StrongName GenerateStrongNameEvidence()
        { 
            byte[] publicKeyBlob = null;
            string simpleName = null; 
            ushort majorVersion = 0; 
            ushort minorVersion = 0;
            ushort build = 0; 
            ushort revision = 0;

            GetStrongNameInformation(m_targetAssembly.GetNativeHandle(),
                                     JitHelpers.GetObjectHandleOnStack(ref publicKeyBlob), 
                                     JitHelpers.GetStringHandleOnStack(ref simpleName),
                                     out majorVersion, 
                                     out minorVersion, 
                                     out build,
                                     out revision); 

            if (publicKeyBlob == null || publicKeyBlob.Length == 0)
            {
                return null; 
            }
 
            return new StrongName(new StrongNamePublicKeyBlob(publicKeyBlob), 
                                  simpleName,
                                  new Version(majorVersion, minorVersion, build, revision), 
                                  m_targetAssembly);
        }

        [DllImport(JitHelpers.QCall, CharSet = CharSet.Unicode)] 
        [SecurityCritical]
        [SuppressUnmanagedCodeSecurity] 
        private static extern void GetAssemblyPermissionRequests(RuntimeAssembly assembly, 
                                                                 ObjectHandleOnStack retMinimumPermissions,
                                                                 ObjectHandleOnStack retOptionalPermissions, 
                                                                 ObjectHandleOnStack retRefusedPermissions);

        /// 
        ///     Get any evidence that was serialized into the assembly 
        /// 
        public IEnumerable GetFactorySuppliedEvidence() 
        { 
            // The PEFile knows how to read the serialized evidence, so we can just delegate to it
            return m_peFileFactory.GetFactorySuppliedEvidence(); 
        }

        [DllImport(JitHelpers.QCall, CharSet = CharSet.Unicode)]
        [SecurityCritical] 
        [SuppressUnmanagedCodeSecurity]
        private static extern void GetStrongNameInformation(RuntimeAssembly assembly, 
                                                            ObjectHandleOnStack retPublicKeyBlob, 
                                                            StringHandleOnStack retSimpleName,
                                                            [Out] out ushort majorVersion, 
                                                            [Out] out ushort minorVersion,
                                                            [Out] out ushort build,
                                                            [Out] out ushort revision);
 
        /// 
        ///     Retarget an evidence object from generating evidence for a PEFile to generating evidence for 
        ///     the file's assembly. 
        /// 
        [SecurityCritical] 
        private static Evidence UpgradeSecurityIdentity(Evidence peFileEvidence, RuntimeAssembly targetAssembly)
        {
            Contract.Assert(peFileEvidence != null);
            Contract.Assert(targetAssembly != null); 
            Contract.Assert(peFileEvidence.Target is PEFileEvidenceFactory, "Expected upgrade path is from PEFile to Assembly");
 
            peFileEvidence.Target = new AssemblyEvidenceFactory(targetAssembly, 
                                                                peFileEvidence.Target as PEFileEvidenceFactory);
 
            // Whidbey hosts would provide evidence for assemblies up front rather than on demand.  If there
            // is a HostSecurityManager which does want to provide evidence, then we should provide it the
            // opprotunity to do the same for compatibility.
            HostSecurityManager securityManager = AppDomain.CurrentDomain.HostSecurityManager; 
            if ((securityManager.Flags & HostSecurityManagerOptions.HostAssemblyEvidence) == HostSecurityManagerOptions.HostAssemblyEvidence)
            { 
                peFileEvidence = securityManager.ProvideAssemblyEvidence(targetAssembly, peFileEvidence); 
                if (peFileEvidence == null)
                { 
                    throw new InvalidOperationException(Environment.GetResourceString("Policy_NullHostEvidence", securityManager.GetType().FullName, targetAssembly.FullName));
                }
            }
 
            return peFileEvidence;
        } 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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AssemblyEvidenceFactory.cs source code in C# .NET

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