Bug fix #4: wrong stream size parsing in some version 3 compound documents not 100% specs compliant

Author: ironfede

sources/OpenMcdf/CompoundFile.cs

@@ -1073,9 +1073,9 @@ private void AllocateFATSectorChain(List<Sector> sectorChain)
                 new StreamView(
                     fatSectors,
                     GetSectorSize(),
-                    header.FATSectorsNumber * GetSectorSize(), 
-                    null, 
-                    sourceStream, 
+                    header.FATSectorsNumber * GetSectorSize(),
+                    null,
+                    sourceStream,
                     true
                     );
 
@@ -1801,7 +1801,7 @@ IDirectoryEntry de
                 = DirectoryEntry.New(String.Empty, StgType.StgInvalid, directoryEntries);
 
                 //We are not inserting dirs. Do not use 'InsertNewDirectoryEntry'
-                de.Read(dirReader);
+                de.Read(dirReader, this.Version);
 
             }
         }

sources/OpenMcdf/DirectoryEntry.cs

@@ -378,7 +378,7 @@ public void Write(Stream stream)
         //    return ms.ToArray();
         //}
 
-        public void Read(Stream stream)
+        public void Read(Stream stream, CFSVersion ver = CFSVersion.Ver_3)
         {
             StreamRW rw = new StreamRW(stream);
 
@@ -404,7 +404,19 @@ public void Read(Stream stream)
             creationDate = rw.ReadBytes(8);
             modifyDate = rw.ReadBytes(8);
             startSetc = rw.ReadInt32();
-            size = rw.ReadInt64();
+
+            if (ver == CFSVersion.Ver_3)
+            {
+                // avoid dirty read for version 3 files (max size: 32bit integer)
+                // where most significant bits are not initialized to zero
+
+                size = rw.ReadInt32();
+                rw.ReadBytes(4); //discard most significant 4 (possibly) dirty bytes
+            }
+            else
+            {
+                size = rw.ReadInt64();
+            }
         }
 
         public string Name

sources/OpenMcdf/IDirectoryEntry.cs

@@ -23,7 +23,7 @@ internal interface IDirectoryEntry : IComparable, IRBNode
         byte[] ModifyDate { get; set; }
         string Name { get; }
         ushort NameLength { get; set; }
-        void Read(System.IO.Stream stream);
+        void Read(System.IO.Stream stream, CFSVersion ver = CFSVersion.Ver_3);
         int RightSibling { get; set; }
         void SetEntryName(string entryName);
         int SID { get; set; }

sources/Structured Storage Explorer/MainForm.cs

@@ -454,20 +454,22 @@ private void treeView1_MouseUp(object sender, MouseEventArgs e)
                 exportDataToolStripMenuItem.Enabled = false;
             }
 
-            propertyGrid1.SelectedObject = n.Tag;
-
+            if (n != null)
+                propertyGrid1.SelectedObject = n.Tag;
 
 
-            CFStream targetStream = n.Tag as CFStream;
-            if (targetStream != null)
-            {
-                this.hexEditor.ByteProvider = new StreamDataProvider(targetStream);
-            }
-            else
+            if (n != null)
             {
-                this.hexEditor.ByteProvider = null;
+                CFStream targetStream = n.Tag as CFStream;
+                if (targetStream != null)
+                {
+                    this.hexEditor.ByteProvider = new StreamDataProvider(targetStream);
+                }
+                else
+                {
+                    this.hexEditor.ByteProvider = null;
+                }
             }
-
         }
 
         void hexEditor_ByteProviderChanged(object sender, EventArgs e)