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Checks maximum path length using .NET features.
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This changes the ProjectWriter class so that files created by it are
validated using DirectoryInfo and/or FileInfo classes.

Also adjusts hardcoded path lengths to:
- use actual maximum windows' LongPaths feature allows (32767),
- specify exact path part character limit (258-12), which reserves
  characters for the 8.3 legacy file name format,
- increases unsupported platforms' limit to 200 characters instead of 30

Now WholeProjectDecompiler class will always check for full path while
trying to create files to properly validate maximum path length exceeds.

The hardcoded maxPathLength value (258) was tested to its edge cases, in
which Visual Studio 2022 would allow a value of up to 259, whereas Notepad++
and WordPad won't open files with paths that long.

Arbitrary values would also work (as far as DirInfo doesn't throw an
exception, but most Windows applications wouldn't be able to handle the
files.

Related GitHub issue: icsharpcode#2706.
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Heavenly Avenger committed Jun 13, 2022
1 parent 874ac9a commit dc5512c
Showing 1 changed file with 96 additions and 106 deletions.
202 changes: 96 additions & 106 deletions ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -133,7 +133,7 @@ protected WholeProjectDecompiler(
public void DecompileProject(PEFile moduleDefinition, string targetDirectory, CancellationToken cancellationToken = default(CancellationToken))
{
string projectFileName = Path.Combine(targetDirectory, CleanUpFileName(moduleDefinition.Name) + ".csproj");
using (var writer = new StreamWriter(projectFileName))
using (var writer = new StreamWriter(ValidatePath(projectFileName)))
{
DecompileProject(moduleDefinition, targetDirectory, writer, cancellationToken);
}
Expand All @@ -145,14 +145,14 @@ protected WholeProjectDecompiler(
{
throw new InvalidOperationException("Must set TargetDirectory");
}
TargetDirectory = targetDirectory;
TargetDirectory = new DirectoryInfo(targetDirectory).FullName;
directories.Clear();
var files = WriteCodeFilesInProject(moduleDefinition, cancellationToken).ToList();
files.AddRange(WriteResourceFilesInProject(moduleDefinition));
files.AddRange(WriteMiscellaneousFilesInProject(moduleDefinition));
if (StrongNameKeyFile != null)
{
File.Copy(StrongNameKeyFile, Path.Combine(targetDirectory, Path.GetFileName(StrongNameKeyFile)), overwrite: true);
File.Copy(StrongNameKeyFile, ValidatePath(Path.Combine(targetDirectory, Path.GetFileName(StrongNameKeyFile))), overwrite: true);
}

projectWriter.Write(projectFileWriter, this, files, moduleDefinition);
Expand Down Expand Up @@ -191,9 +191,9 @@ CSharpDecompiler CreateDecompiler(DecompilerTypeSystem ts)

const string prop = "Properties";
if (directories.Add(prop))
Directory.CreateDirectory(Path.Combine(TargetDirectory, prop));
Directory.CreateDirectory(ValidatePath(Path.Combine(TargetDirectory, prop), true));
string assemblyInfo = Path.Combine(prop, "AssemblyInfo.cs");
using (StreamWriter w = new StreamWriter(Path.Combine(TargetDirectory, assemblyInfo)))
using (StreamWriter w = new StreamWriter(ValidatePath(Path.Combine(TargetDirectory, assemblyInfo))))
{
syntaxTree.AcceptVisitor(new CSharpOutputVisitor(w, Settings.CSharpFormattingOptions));
}
Expand All @@ -216,7 +216,7 @@ CSharpDecompiler CreateDecompiler(DecompilerTypeSystem ts)
{
string dir = Settings.UseNestedDirectoriesForNamespaces ? CleanUpPath(ns) : CleanUpDirectoryName(ns);
if (directories.Add(dir))
Directory.CreateDirectory(Path.Combine(TargetDirectory, dir));
Directory.CreateDirectory(ValidatePath(Path.Combine(TargetDirectory, dir), true));
return Path.Combine(dir, file);
}
}, StringComparer.OrdinalIgnoreCase).ToList();
Expand All @@ -230,7 +230,7 @@ CSharpDecompiler CreateDecompiler(DecompilerTypeSystem ts)
CancellationToken = cancellationToken
},
delegate (IGrouping<string, TypeDefinitionHandle> file) {
using (StreamWriter w = new StreamWriter(Path.Combine(TargetDirectory, file.Key)))
using (StreamWriter w = new StreamWriter(ValidatePath(Path.Combine(TargetDirectory, file.Key))))
{
try
{
Expand Down Expand Up @@ -274,7 +274,7 @@ CSharpDecompiler CreateDecompiler(DecompilerTypeSystem ts)
string dirName = Path.GetDirectoryName(fileName);
if (!string.IsNullOrEmpty(dirName) && directories.Add(dirName))
{
Directory.CreateDirectory(Path.Combine(TargetDirectory, dirName));
Directory.CreateDirectory(ValidatePath(Path.Combine(TargetDirectory, dirName)));
}
Stream entryStream = (Stream)value;
entryStream.Position = 0;
Expand Down Expand Up @@ -316,7 +316,7 @@ CSharpDecompiler CreateDecompiler(DecompilerTypeSystem ts)
else
{
string fileName = GetFileNameForResource(r.Name);
using (FileStream fs = new FileStream(Path.Combine(TargetDirectory, fileName), FileMode.Create, FileAccess.Write))
using (FileStream fs = new FileStream(ValidatePath(Path.Combine(TargetDirectory, fileName)), FileMode.Create, FileAccess.Write))
{
stream.Position = 0;
stream.CopyTo(fs);
Expand All @@ -333,7 +333,7 @@ CSharpDecompiler CreateDecompiler(DecompilerTypeSystem ts)
string resx = Path.ChangeExtension(fileName, ".resx");
try
{
using (FileStream fs = new FileStream(Path.Combine(TargetDirectory, resx), FileMode.Create, FileAccess.Write))
using (FileStream fs = new FileStream(ValidatePath(Path.Combine(TargetDirectory, resx)), FileMode.Create, FileAccess.Write))
using (ResXResourceWriter writer = new ResXResourceWriter(fs))
{
foreach (var entry in new ResourcesFile(entryStream))
Expand All @@ -352,7 +352,7 @@ CSharpDecompiler CreateDecompiler(DecompilerTypeSystem ts)
// if the .resources can't be decoded, just save them as-is
}
}
using (FileStream fs = new FileStream(Path.Combine(TargetDirectory, fileName), FileMode.Create, FileAccess.Write))
using (FileStream fs = new FileStream(ValidatePath(Path.Combine(TargetDirectory, fileName)), FileMode.Create, FileAccess.Write))
{
entryStream.CopyTo(fs);
}
Expand Down Expand Up @@ -396,21 +396,21 @@ string GetFileNameForResource(string fullName)
byte[] appIcon = CreateApplicationIcon(resources);
if (appIcon != null)
{
File.WriteAllBytes(Path.Combine(TargetDirectory, "app.ico"), appIcon);
File.WriteAllBytes(ValidatePath(Path.Combine(TargetDirectory, "app.ico")), appIcon);
yield return ("ApplicationIcon", "app.ico");
}

byte[] appManifest = CreateApplicationManifest(resources);
if (appManifest != null && !IsDefaultApplicationManifest(appManifest))
{
File.WriteAllBytes(Path.Combine(TargetDirectory, "app.manifest"), appManifest);
File.WriteAllBytes(ValidatePath(Path.Combine(TargetDirectory, "app.manifest")), appManifest);
yield return ("ApplicationManifest", "app.manifest");
}

var appConfig = module.FileName + ".config";
if (File.Exists(appConfig))
{
File.Copy(appConfig, Path.Combine(TargetDirectory, "app.config"), overwrite: true);
File.Copy(appConfig, ValidatePath(Path.Combine(TargetDirectory, "app.config")), overwrite: true);
yield return ("ApplicationConfig", Path.GetFileName(appConfig));
}
}
Expand Down Expand Up @@ -554,16 +554,16 @@ static string CleanUpApplicationManifest(byte[] appManifest)
var value = (int?)fileSystem.GetValue("LongPathsEnabled");
if (value == 1)
{
return (true, int.MaxValue, 255);
return (true, 32767, 258 - 12);
}
return (false, 200, 30);
return (false, 258, 258 - 12);
default:
return (false, 200, 30);
return (false, 200, 200);
}
}
catch
{
return (false, 200, 30);
return (false, 200, 200);
}
}

Expand All @@ -572,7 +572,7 @@ static string CleanUpApplicationManifest(byte[] appManifest)
/// </summary>
public static string CleanUpFileName(string text)
{
return CleanUpName(text, separateAtDots: false, treatAsFileName: false);
return CleanUpName(text, separateAtDots: false, lookForExtension: false);
}

/// <summary>
Expand All @@ -581,115 +581,48 @@ public static string CleanUpFileName(string text)
/// </summary>
public static string SanitizeFileName(string fileName)
{
return CleanUpName(fileName, separateAtDots: false, treatAsFileName: true);
return CleanUpName(fileName, separateAtDots: false, lookForExtension: true);
}

/// <summary>
/// Cleans up a node name for use as a file system name. If <paramref name="separateAtDots"/> is active,
/// dots are seen as segment separators. Each segment is limited to maxSegmentLength characters.
/// (see <see cref="GetLongPathSupport"/>) If <paramref name="treatAsFileName"/> is active,
/// we check for file a extension and try to preserve it, if it's valid.
/// dots are seen as segment separators. If <paramref name="lookForExtension"/> is active,
/// we check for file a extension and try to preserve it when separating paths at dots.
/// </summary>
static string CleanUpName(string text, bool separateAtDots, bool treatAsFileName)
static string CleanUpName(string name, bool separateAtDots, bool lookForExtension)
{
int pos = text.IndexOf(':');
if (pos > 0)
text = text.Substring(0, pos);
pos = text.IndexOf('`');
if (pos > 0)
text = text.Substring(0, pos);
text = text.Trim();
string extension = null;
int currentSegmentLength = 0;
var (supportsLongPaths, maxPathLength, maxSegmentLength) = longPathSupport.Value;
if (treatAsFileName)
string ext = string.Empty;
string cleanName = name;

if (separateAtDots)
{
// Check if input is a file name, i.e., has a valid extension
// If yes, preserve extension and append it at the end.
// But only, if the extension length does not exceed maxSegmentLength,
// if that's the case we just give up and treat the extension no different
// from the file name.
int lastDot = text.LastIndexOf('.');
if (lastDot >= 0 && text.Length - lastDot < maxSegmentLength)
if (lookForExtension)
{
string originalText = text;
extension = text.Substring(lastDot);
text = text.Remove(lastDot);
foreach (var c in extension)
{
if (!(char.IsLetterOrDigit(c) || c == '-' || c == '_' || c == '.'))
{
// extension contains an invalid character, therefore cannot be a valid extension.
extension = null;
text = originalText;
break;
}
}
ext = Path.GetExtension(name);
cleanName = name.Substring(0, name.Length - ext.Length);
}
cleanName = cleanName.Replace('.', Path.DirectorySeparatorChar);
}
// Whitelist allowed characters, replace everything else:
StringBuilder b = new StringBuilder(text.Length + (extension?.Length ?? 0));
foreach (var c in text)
{
currentSegmentLength++;
if (char.IsLetterOrDigit(c) || c == '-' || c == '_')
{
// if the current segment exceeds maxSegmentLength characters,
// skip until the end of the segment.
if (currentSegmentLength <= maxSegmentLength)
b.Append(c);
}
else if (c == '.' && b.Length > 0 && b[b.Length - 1] != '.')
{
// if the current segment exceeds maxSegmentLength characters,
// skip until the end of the segment.
if (separateAtDots || currentSegmentLength <= maxSegmentLength)
b.Append('.'); // allow dot, but never two in a row

// Reset length at end of segment.
if (separateAtDots)
currentSegmentLength = 0;
}
else if (treatAsFileName && (c == '/' || c == '\\') && currentSegmentLength > 0)
{
// if we treat this as a file name, we've started a new segment
b.Append(c);
currentSegmentLength = 0;
}
else
{
// if the current segment exceeds maxSegmentLength characters,
// skip until the end of the segment.
if (currentSegmentLength <= maxSegmentLength)
b.Append('-');
}
if (b.Length >= maxPathLength && !supportsLongPaths)
break; // limit to 200 chars, if long paths are not supported.
}
if (b.Length == 0)
b.Append('-');
string name = b.ToString();
if (extension != null)
name += extension;
if (IsReservedFileSystemName(name))
return name + "_";

if (IsReservedFileSystemName(cleanName + ext))
cleanName += "_";
else if (name == ".")
return "_";
else
return name;
cleanName = "_";

return cleanName + ext;
}

/// <summary>
/// Cleans up a node name for use as a directory name.
/// </summary>
public static string CleanUpDirectoryName(string text)
{
return CleanUpName(text, separateAtDots: false, treatAsFileName: false);
return CleanUpName(text, separateAtDots: false, lookForExtension: false);
}

public static string CleanUpPath(string text)
{
return CleanUpName(text, separateAtDots: true, treatAsFileName: false)
return CleanUpName(text, separateAtDots: true, lookForExtension: true)
.Replace('.', Path.DirectorySeparatorChar);
}

Expand Down Expand Up @@ -729,6 +662,63 @@ public static bool CanUseSdkStyleProjectFormat(PEFile module)
{
return TargetServices.DetectTargetFramework(module).Moniker != null;
}

/// <summary>
/// Validates whether a path is valid for a given file system
/// </summary>
/// <param name="path">Absolute path to validate.</param>
public string ValidatePath(string path, bool directory = false)
{
var (supportsLongPaths, maxPathLength, maxSegmentLength) = longPathSupport.Value;
if (!Path.IsPathRooted(path))
throw new Exception("Non-root path passed to ValidatePath().");

string dotnetPath;
try
{
// FileSystemInfo siblings shall throw an exception in case the path is not valid.
dotnetPath = directory ? new DirectoryInfo(path).FullName : new FileInfo(path).FullName;
}
catch (Exception ex)
{
if (path.Length > maxPathLength)
{
throw new PathTooLongException("Path too long. Max: " + maxPathLength + " - Length: " + path.Length + Environment.NewLine +
"Path: " + path, ex);
}
else if (path.Contains(Path.DirectorySeparatorChar))
{
var parts = path.Split(Path.DirectorySeparatorChar);

foreach (var part in parts)
{
if (part.Length > maxSegmentLength)
{
throw new PathTooLongException("Part of path is too long. Max: " + maxSegmentLength + "- Length: " + part.Length + Environment.NewLine +
"Path part: " + part + Environment.NewLine +
"Full path: " + path,
ex);
}
}
}

throw new Exception("Path not valid.", ex);
}

if (dotnetPath.Length > maxPathLength)
{
if (Environment.OSVersion.Platform == PlatformID.Win32NT && !supportsLongPaths)
throw new PathTooLongException("Path is too long. Files could be created, but they won't be accessible by most applications." + Environment.NewLine +
"Path: " + dotnetPath + Environment.NewLine +
"Length: " + dotnetPath.Length + " - Maximum allowed: " + maxPathLength);
else
throw new PathTooLongException("Path is too long (" + dotnetPath.Length + " characters). ILSpy is configured not to allow paths with more than " +
maxPathLength + " characters." + Environment.NewLine +
"Path: " + dotnetPath);
}

return dotnetPath;
}
}

public readonly struct DecompilationProgress
Expand Down

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