mcs/class/referencesource/mscorlib/system/security/policy/filecodegroup.cs

   1 // ==++==
   2 //
   3 //   Copyright (c) Microsoft Corporation.  All rights reserved.
   4 //
   5 // ==--==
   6 // <OWNER>Microsoft</OWNER>
   7 //
   8
   9 //
  10 // FileCodeGroup.cs
  11 //
  12 // Representation for code groups used for the policy mechanism.
  13 //
  14
  15 namespace System.Security.Policy {
  16     using System;
  17     using System.Collections;
  18     using System.Globalization;
  19     using System.Security.Permissions;
  20     using System.Security.Util;
  21     using System.Runtime.Serialization;
  22     using System.Runtime.Versioning;
  23     using System.Diagnostics.Contracts;
  24
  25     [Serializable]
  26     [System.Runtime.InteropServices.ComVisible(true)]
  27     sealed public class FileCodeGroup : CodeGroup, IUnionSemanticCodeGroup {
  28         private FileIOPermissionAccess m_access;
  29
  30         internal FileCodeGroup() : base() {}
  31
  32         public FileCodeGroup(IMembershipCondition membershipCondition, FileIOPermissionAccess access)
  33             : base(membershipCondition, (PolicyStatement)null) {
  34             m_access = access;
  35         }
  36
  37         [System.Security.SecuritySafeCritical]  // auto-generated
  38         [ResourceExposure(ResourceScope.Machine)]
  39         [ResourceConsumption(ResourceScope.Machine)]
  40         public override PolicyStatement Resolve(Evidence evidence) {
  41             if (evidence == null)
  42                 throw new ArgumentNullException("evidence");
  43             Contract.EndContractBlock();
  44
  45             object usedEvidence = null;
  46
  47             if (PolicyManager.CheckMembershipCondition(MembershipCondition, evidence, out usedEvidence)) {
  48                 PolicyStatement thisPolicy = CalculateAssemblyPolicy(evidence);
  49
  50                 // If any delay-evidence was used to generate this grant set, then we need to keep track of
  51                 // that for potentially later forcing it to be verified.
  52                 IDelayEvaluatedEvidence delayEvidence = usedEvidence as IDelayEvaluatedEvidence;
  53                 bool delayEvidenceNeedsVerification = delayEvidence != null && !delayEvidence.IsVerified;
  54                 if (delayEvidenceNeedsVerification) {
  55                     thisPolicy.AddDependentEvidence(delayEvidence);
  56                 }
  57
  58                 bool foundExclusiveChild = false;
  59                 IEnumerator enumerator = this.Children.GetEnumerator();
  60                 while (enumerator.MoveNext() && !foundExclusiveChild) {
  61                     PolicyStatement childPolicy = PolicyManager.ResolveCodeGroup(enumerator.Current as CodeGroup,
  62                                                                                  evidence);
  63
  64                     if (childPolicy != null) {
  65                         thisPolicy.InplaceUnion(childPolicy);
  66
  67                         if ((childPolicy.Attributes & PolicyStatementAttribute.Exclusive) == PolicyStatementAttribute.Exclusive) {
  68                             foundExclusiveChild = true;
  69                         }
  70                     }
  71                 }
  72
  73                 return thisPolicy;
  74             }
  75             else {
  76                 return null;
  77             }
  78         }
  79
  80         /// <internalonly/>
  81         [ResourceExposure(ResourceScope.Machine)]
  82         [ResourceConsumption(ResourceScope.Machine)]
  83         PolicyStatement IUnionSemanticCodeGroup.InternalResolve(Evidence evidence) {
  84             if (evidence == null)
  85                 throw new ArgumentNullException("evidence");
  86             Contract.EndContractBlock();
  87
  88             if (this.MembershipCondition.Check(evidence)) {
  89                 return CalculateAssemblyPolicy(evidence);
  90             }
  91
  92             return null;
  93         }
  94
  95         public override CodeGroup ResolveMatchingCodeGroups(Evidence evidence) {
  96             if (evidence == null)
  97                 throw new ArgumentNullException("evidence");
  98             Contract.EndContractBlock();
  99
 100             if (this.MembershipCondition.Check(evidence)) {
 101                 CodeGroup retGroup = this.Copy();
 102                 retGroup.Children = new ArrayList();
 103                 IEnumerator enumerator = this.Children.GetEnumerator();
 104                 while (enumerator.MoveNext()) {
 105                     CodeGroup matchingGroups = ((CodeGroup)enumerator.Current).ResolveMatchingCodeGroups(evidence);
 106                     // If the child has a policy, we are done.
 107                     if (matchingGroups != null)
 108                         retGroup.AddChild(matchingGroups);
 109                 }
 110                 return retGroup;
 111             }
 112             else {
 113                 return null;
 114             }
 115         }
 116
 117         [ResourceExposure(ResourceScope.Machine)]
 118         [ResourceConsumption(ResourceScope.Machine)]
 119         internal PolicyStatement CalculatePolicy(Url url) {
 120             URLString urlString = url.GetURLString();
 121             if (String.Compare(urlString.Scheme, "file", StringComparison.OrdinalIgnoreCase) != 0)
 122                 return null;
 123
 124             string directory = urlString.GetDirectoryName();
 125             PermissionSet permSet = new PermissionSet(PermissionState.None);
 126             permSet.SetPermission(new FileIOPermission(m_access, System.IO.Path.GetFullPath(directory)));
 127
 128             return new PolicyStatement(permSet, PolicyStatementAttribute.Nothing);
 129         }
 130
 131         [ResourceExposure(ResourceScope.Machine)]
 132         [ResourceConsumption(ResourceScope.Machine)]
 133         private PolicyStatement CalculateAssemblyPolicy(Evidence evidence) {
 134             PolicyStatement thisPolicy = null;
 135
 136             Url url = evidence.GetHostEvidence<Url>();
 137             if (url != null) {
 138                 thisPolicy = CalculatePolicy(url);
 139             }
 140
 141             if (thisPolicy == null) {
 142                 thisPolicy = new PolicyStatement(new PermissionSet(false), PolicyStatementAttribute.Nothing);
 143             }
 144
 145             return thisPolicy;
 146         }
 147
 148         public override CodeGroup Copy() {
 149             FileCodeGroup group = new FileCodeGroup(this.MembershipCondition, this.m_access);
 150             group.Name = this.Name;
 151             group.Description = this.Description;
 152
 153             IEnumerator enumerator = this.Children.GetEnumerator();
 154             while (enumerator.MoveNext()) {
 155                 group.AddChild((CodeGroup)enumerator.Current);
 156             }
 157             return group;
 158         }
 159
 160         public override string MergeLogic {
 161             get {
 162                 return Environment.GetResourceString("MergeLogic_Union");
 163             }
 164         }
 165
 166         public override string PermissionSetName {
 167             get {
 168                 return Environment.GetResourceString("FileCodeGroup_PermissionSet", XMLUtil.BitFieldEnumToString(typeof(FileIOPermissionAccess), m_access));
 169             }
 170         }
 171
 172         public override string AttributeString {
 173             get {
 174                 return null;
 175             }
 176         }
 177
 178         protected override void CreateXml(SecurityElement element, PolicyLevel level) {
 179             element.AddAttribute("Access", XMLUtil.BitFieldEnumToString(typeof(FileIOPermissionAccess), m_access));
 180         }
 181
 182         protected override void ParseXml(SecurityElement e, PolicyLevel level) {
 183             string access = e.Attribute("Access");
 184             if (access != null)
 185                 m_access = (FileIOPermissionAccess) Enum.Parse(typeof(FileIOPermissionAccess), access);
 186             else
 187                 m_access = FileIOPermissionAccess.NoAccess;
 188         }
 189
 190         public override bool Equals(Object o) {
 191             FileCodeGroup that = (o as FileCodeGroup);
 192             if (that != null && base.Equals(that)) {
 193                 if (this.m_access == that.m_access)
 194                     return true;
 195             }
 196             return false;
 197         }
 198
 199         public override int GetHashCode() {
 200             return base.GetHashCode() + m_access.GetHashCode();
 201         }
 202
 203         internal override string GetTypeName() {
 204             return "System.Security.Policy.FileCodeGroup";
 205         }
 206     }
 207 }