Initial commit - WPinternals 2.6

DiscUtils/Ntfs/SecurityDescriptor.cs

@@ -0,0 +1,177 @@
+//
+// Copyright (c) 2008-2011, Kenneth Bell
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+//
+
+namespace DiscUtils.Ntfs
+{
+    using System;
+    using System.IO;
+    using System.Security.AccessControl;
+    using System.Security.Principal;
+
+    internal sealed class SecurityDescriptor : IByteArraySerializable, IDiagnosticTraceable
+    {
+        private RawSecurityDescriptor _securityDescriptor;
+
+        public SecurityDescriptor()
+        {
+        }
+
+        public SecurityDescriptor(RawSecurityDescriptor secDesc)
+        {
+            _securityDescriptor = secDesc;
+        }
+
+        public RawSecurityDescriptor Descriptor
+        {
+            get { return _securityDescriptor; }
+            set { _securityDescriptor = value; }
+        }
+
+        public int Size
+        {
+            get
+            {
+                return _securityDescriptor.BinaryLength;
+            }
+        }
+
+        public uint CalcHash()
+        {
+            byte[] buffer = new byte[Size];
+            WriteTo(buffer, 0);
+            uint hash = 0;
+            for (int i = 0; i < buffer.Length / 4; ++i)
+            {
+                hash = Utilities.ToUInt32LittleEndian(buffer, i * 4) + ((hash << 3) | (hash >> 29));
+            }
+
+            return hash;
+        }
+
+        public int ReadFrom(byte[] buffer, int offset)
+        {
+            _securityDescriptor = new RawSecurityDescriptor(buffer, offset);
+            return _securityDescriptor.BinaryLength;
+        }
+
+        public void WriteTo(byte[] buffer, int offset)
+        {
+            // Write out the security descriptor manually because on NTFS the DACL is written
+            // before the Owner & Group.  Writing the components in the same order means the
+            // hashes will match for identical Security Descriptors.
+            ControlFlags controlFlags = _securityDescriptor.ControlFlags;
+            buffer[offset + 0x00] = 1;
+            buffer[offset + 0x01] = _securityDescriptor.ResourceManagerControl;
+            Utilities.WriteBytesLittleEndian((ushort)controlFlags, buffer, offset + 0x02);
+
+            // Blank out offsets, will fill later
+            for (int i = 0x04; i < 0x14; ++i)
+            {
+                buffer[offset + i] = 0;
+            }
+
+            int pos = 0x14;
+
+            RawAcl discAcl = _securityDescriptor.DiscretionaryAcl;
+            if ((controlFlags & ControlFlags.DiscretionaryAclPresent) != 0 && discAcl != null)
+            {
+                Utilities.WriteBytesLittleEndian(pos, buffer, offset + 0x10);
+                discAcl.GetBinaryForm(buffer, offset + pos);
+                pos += _securityDescriptor.DiscretionaryAcl.BinaryLength;
+            }
+            else
+            {
+                Utilities.WriteBytesLittleEndian((int)0, buffer, offset + 0x10);
+            }
+
+            RawAcl sysAcl = _securityDescriptor.SystemAcl;
+            if ((controlFlags & ControlFlags.SystemAclPresent) != 0 && sysAcl != null)
+            {
+                Utilities.WriteBytesLittleEndian(pos, buffer, offset + 0x0C);
+                sysAcl.GetBinaryForm(buffer, offset + pos);
+                pos += _securityDescriptor.SystemAcl.BinaryLength;
+            }
+            else
+            {
+                Utilities.WriteBytesLittleEndian((int)0, buffer, offset + 0x0C);
+            }
+
+            Utilities.WriteBytesLittleEndian(pos, buffer, offset + 0x04);
+            _securityDescriptor.Owner.GetBinaryForm(buffer, offset + pos);
+            pos += _securityDescriptor.Owner.BinaryLength;
+
+            Utilities.WriteBytesLittleEndian(pos, buffer, offset + 0x08);
+            _securityDescriptor.Group.GetBinaryForm(buffer, offset + pos);
+            pos += _securityDescriptor.Group.BinaryLength;
+
+            if (pos != _securityDescriptor.BinaryLength)
+            {
+                throw new IOException("Failed to write Security Descriptor correctly");
+            }
+        }
+
+        public void Dump(TextWriter writer, string indent)
+        {
+            writer.WriteLine(indent + "Descriptor: " + _securityDescriptor.GetSddlForm(AccessControlSections.All));
+        }
+
+        internal static RawSecurityDescriptor CalcNewObjectDescriptor(RawSecurityDescriptor parent, bool isContainer)
+        {
+            RawAcl sacl = InheritAcl(parent.SystemAcl, isContainer);
+            RawAcl dacl = InheritAcl(parent.DiscretionaryAcl, isContainer);
+
+            return new RawSecurityDescriptor(parent.ControlFlags, parent.Owner, parent.Group, sacl, dacl);
+        }
+
+        private static RawAcl InheritAcl(RawAcl parentAcl, bool isContainer)
+        {
+            AceFlags inheritTest = isContainer ? AceFlags.ContainerInherit : AceFlags.ObjectInherit;
+
+            RawAcl newAcl = null;
+            if (parentAcl != null)
+            {
+                newAcl = new RawAcl(parentAcl.Revision, parentAcl.Count);
+                foreach (GenericAce ace in parentAcl)
+                {
+                    if ((ace.AceFlags & inheritTest) != 0)
+                    {
+                        GenericAce newAce = ace.Copy();
+
+                        AceFlags newFlags = ace.AceFlags;
+                        if ((newFlags & AceFlags.NoPropagateInherit) != 0)
+                        {
+                            newFlags &= ~(AceFlags.ContainerInherit | AceFlags.ObjectInherit | AceFlags.NoPropagateInherit);
+                        }
+
+                        newFlags &= ~AceFlags.InheritOnly;
+                        newFlags |= AceFlags.Inherited;
+
+                        newAce.AceFlags = newFlags;
+                        newAcl.InsertAce(newAcl.Count, newAce);
+                    }
+                }
+            }
+
+            return newAcl;
+        }
+    }
+}