HashMembershipCondition.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Security / Policy / HashMembershipCondition.cs / 1305376 / HashMembershipCondition.cs

                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
// [....]
// 
 
//
// HashMembershipCondition.cs 
//
// Implementation of membership condition for hashes of assemblies.
//
 
namespace System.Security.Policy {
    using System.Collections; 
    using System.Runtime.Serialization; 
    using System.Security;
    using System.Security.Cryptography; 
    using System.Security.Util;
    using System.Security.Permissions;
    using System.Threading;
    using System.Globalization; 
    using System.Diagnostics.Contracts;
 
    [Serializable] 
    [System.Runtime.InteropServices.ComVisible(true)]
    public sealed class HashMembershipCondition : ISerializable, IDeserializationCallback, IMembershipCondition, IReportMatchMembershipCondition { 
        private byte[] m_value = null;
        private HashAlgorithm m_hashAlg = null;
        private SecurityElement m_element = null;
 
        private object s_InternalSyncObject = null;
        private object InternalSyncObject { 
            get { 
                if (s_InternalSyncObject == null) {
                    Object o = new Object(); 
                    Interlocked.CompareExchange(ref s_InternalSyncObject, o, null);
                }
                return s_InternalSyncObject;
            } 
        }
 
        internal HashMembershipCondition() {} 
        private HashMembershipCondition (SerializationInfo info, StreamingContext context) {
            m_value = (byte[]) info.GetValue("HashValue", typeof(byte[])); 
            string hashAlgorithm = (string) info.GetValue("HashAlgorithm", typeof(string));
            if (hashAlgorithm != null)
                m_hashAlg = HashAlgorithm.Create(hashAlgorithm);
            else 
                m_hashAlg = new SHA1Managed();
        } 
 
        public HashMembershipCondition(HashAlgorithm hashAlg, byte[] value) {
            if (value == null) 
                throw new ArgumentNullException("value");
            if (hashAlg == null)
                throw new ArgumentNullException("hashAlg");
            Contract.EndContractBlock(); 

            m_value = new byte[value.Length]; 
            Array.Copy(value, m_value, value.Length); 
            m_hashAlg = hashAlg;
        } 

        /// 
        [System.Security.SecurityCritical]
        void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context) 
        {
            info.AddValue("HashValue", this.HashValue); 
            info.AddValue("HashAlgorithm", this.HashAlgorithm.ToString()); 
        }
 
        /// 
        void IDeserializationCallback.OnDeserialization (Object sender) {}

        public HashAlgorithm HashAlgorithm { 
            set {
                if (value == null) 
                    throw new ArgumentNullException("HashAlgorithm"); 
                Contract.EndContractBlock();
                m_hashAlg = value; 
            }
            [System.Security.SecuritySafeCritical]  // auto-generated
            get {
                if (m_hashAlg == null && m_element != null) 
                    ParseHashAlgorithm();
                return m_hashAlg; 
            } 
        }
 
        public byte[] HashValue {
            set {
                if (value == null)
                    throw new ArgumentNullException("value"); 
                Contract.EndContractBlock();
                m_value = new byte[value.Length]; 
                Array.Copy(value, m_value, value.Length); 
            }
            get { 
                if (m_value == null && m_element != null)
                    ParseHashValue();
                if (m_value == null)
                    return null; 

                byte[] value = new byte[m_value.Length]; 
                Array.Copy(m_value, value, m_value.Length); 
                return value;
            } 
        }

        public bool Check(Evidence evidence) {
            object usedEvidence = null; 
            return (this as IReportMatchMembershipCondition).Check(evidence, out usedEvidence);
        } 
 
        bool IReportMatchMembershipCondition.Check(Evidence evidence, out object usedEvidence) {
            usedEvidence = null; 

            if (evidence == null)
                return false;
 
            Hash hash = evidence.GetHostEvidence();
            if (hash != null) { 
                if (m_value == null && m_element != null) 
                    ParseHashValue();
 
                if (m_hashAlg == null && m_element != null)
                    ParseHashAlgorithm();

                byte[] asmHash = null; 
                lock (InternalSyncObject) {
                    asmHash = hash.GenerateHash(m_hashAlg); 
                } 

                if (asmHash != null && CompareArrays(asmHash, m_value)) { 
                    usedEvidence = hash;
                    return true;
                }
            } 

            return false; 
        } 

        [System.Security.SecuritySafeCritical]  // auto-generated 
        public IMembershipCondition Copy() {
            if (m_value == null && m_element != null)
                ParseHashValue();
 
            if (m_hashAlg == null && m_element != null)
                ParseHashAlgorithm(); 
 
            return new HashMembershipCondition(m_hashAlg, m_value);
        } 

        [System.Security.SecuritySafeCritical]  // auto-generated
        public SecurityElement ToXml() {
            return ToXml(null); 
        }
 
        public void FromXml(SecurityElement e) { 
            FromXml(e, null);
        } 

        [System.Security.SecuritySafeCritical]  // auto-generated
        public SecurityElement ToXml(PolicyLevel level) {
            if (m_value == null && m_element != null) 
                ParseHashValue();
 
            if (m_hashAlg == null && m_element != null) 
                ParseHashAlgorithm();
 
            SecurityElement root = new SecurityElement("IMembershipCondition");
            XMLUtil.AddClassAttribute(root, this.GetType(), "System.Security.Policy.HashMembershipCondition");
            // If you hit this assert then most likely you are trying to change the name of this class.
            // This is ok as long as you change the hard coded string above and change the assert below. 
            Contract.Assert(this.GetType().FullName.Equals("System.Security.Policy.HashMembershipCondition"), "Class name changed!");
 
            root.AddAttribute("version", "1"); 
            if (m_value != null)
                root.AddAttribute(s_tagHashValue, Hex.EncodeHexString(HashValue)); 
            if (m_hashAlg != null)
                root.AddAttribute(s_tagHashAlgorithm, HashAlgorithm.GetType().FullName);
            return root;
        } 

        public void FromXml(SecurityElement e, PolicyLevel level) { 
            if (e == null) 
                throw new ArgumentNullException("e");
 
            if (!e.Tag.Equals("IMembershipCondition"))
                throw new ArgumentException(Environment.GetResourceString("Argument_MembershipConditionElement"));
            Contract.EndContractBlock();
 
            lock (InternalSyncObject) {
                m_element = e; 
                m_value = null; 
                m_hashAlg = null;
            } 
        }

        [System.Security.SecuritySafeCritical]  // auto-generated
        public override bool Equals(Object o) { 
            HashMembershipCondition that = (o as HashMembershipCondition);
            if (that != null) { 
                if (this.m_hashAlg == null && this.m_element != null) 
                    this.ParseHashAlgorithm();
                if (that.m_hashAlg == null && that.m_element != null) 
                    that.ParseHashAlgorithm();

                if (this.m_hashAlg != null && that.m_hashAlg != null &&
                    this.m_hashAlg.GetType() == that.m_hashAlg.GetType()) { 
                    if (this.m_value == null && this.m_element != null)
                        this.ParseHashValue(); 
                    if (that.m_value == null && that.m_element != null) 
                        that.ParseHashValue();
 
                    if (this.m_value.Length != that.m_value.Length)
                        return false;

                    for (int i = 0; i < m_value.Length; i++) { 
                        if (this.m_value[i] != that.m_value[i])
                            return false; 
                    } 
                    return true;
                } 
            }
            return false;
        }
 
        [System.Security.SecuritySafeCritical]  // auto-generated
        public override int GetHashCode() { 
            if (this.m_hashAlg == null && this.m_element != null) 
                this.ParseHashAlgorithm();
 
            int accumulator = this.m_hashAlg != null ? this.m_hashAlg.GetType().GetHashCode() : 0;
            if (this.m_value == null && this.m_element != null)
                this.ParseHashValue();
 
            accumulator = accumulator ^ GetByteArrayHashCode(this.m_value);
            return accumulator; 
        } 

        [System.Security.SecuritySafeCritical]  // auto-generated 
        public override string ToString() {
            if (m_hashAlg == null)
                ParseHashAlgorithm();
 
            return Environment.GetResourceString("Hash_ToString", m_hashAlg.GetType().AssemblyQualifiedName, Hex.EncodeHexString(HashValue));
        } 
 
        private const string s_tagHashValue = "HashValue";
        private const string s_tagHashAlgorithm = "HashAlgorithm"; 

        private void ParseHashValue() {
            lock (InternalSyncObject) {
                if (m_element == null) 
                    return;
 
                string elHash = m_element.Attribute(s_tagHashValue); 
                if (elHash != null)
                    m_value = Hex.DecodeHexString(elHash); 
                else
                    throw new ArgumentException(Environment.GetResourceString("Argument_InvalidXMLElement", s_tagHashValue, this.GetType().FullName));

                if (m_value != null && m_hashAlg != null) { 
                    m_element = null;
                } 
            } 
        }
 
        private void ParseHashAlgorithm() {
            lock (InternalSyncObject) {
                if (m_element == null)
                    return; 

                string elHashAlg = m_element.Attribute(s_tagHashAlgorithm); 
                if (elHashAlg != null) 
                    m_hashAlg = HashAlgorithm.Create(elHashAlg);
                else 
                    m_hashAlg = new SHA1Managed();

                if (m_value != null && m_hashAlg != null)
                    m_element = null; 
            }
        } 
 
        private static bool CompareArrays(byte[] first, byte[] second) {
            if (first.Length != second.Length) 
                return false;

            int count = first.Length;
            for (int i = 0; i < count; ++i) { 
                if (first[i] != second[i])
                    return false; 
            } 

            return true; 
        }

        private static int GetByteArrayHashCode(byte[] baData) {
            if (baData == null) 
                return 0;
 
            int accumulator = 0; 
            for (int i = 0; i < baData.Length; ++i) {
                accumulator = (accumulator << 8) ^ (int)baData[i] ^ (accumulator >> 24); 
            }
            return accumulator;
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
                        

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