Fix relative symlink support in TarFile

src/libraries/System.Formats.Tar/src/System/Formats/Tar/TarEntry.cs

@@ -349,11 +349,17 @@ internal Task ExtractRelativeToDirectoryAsync(string destinationDirectoryPath, b
  throw new InvalidDataException(SR.TarEntryHardLinkOrSymlinkLinkNameEmpty);
  }
 
- linkTargetPath = GetSanitizedFullPath(destinationDirectoryPath, LinkName);
+ linkTargetPath = GetSanitizedFullPath(destinationDirectoryPath,
+ Path.IsPathFullyQualified(LinkName) ? LinkName : Path.Join(Path.GetDirectoryName(fileDestinationPath), LinkName));
+
  if (linkTargetPath == null)
  {
  throw new IOException(SR.Format(SR.TarExtractingResultsLinkOutside, LinkName, destinationDirectoryPath));
  }
+
+ // after TarExtractingResultsLinkOutside validation, preserve the original
+ // symlink target path (to match behavior of other utilities).
+ linkTargetPath = LinkName;
  }
 
  return (fileDestinationPath, linkTargetPath);

src/libraries/System.Formats.Tar/tests/System.Formats.Tar.Tests.csproj

@@ -2,7 +2,7 @@
  <PropertyGroup>
  <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetCoreAppCurrent)-Unix</TargetFrameworks>
  <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
- <StringResourcesPath>$(LibrariesProjectRoot)/Common/tests/Resources/Strings.resx</StringResourcesPath>
+ <StringResourcesPath>$(MSBuildProjectDirectory)\..\src\Resources\Strings.resx</StringResourcesPath>
  <EnableLibraryImportGenerator>true</EnableLibraryImportGenerator>
  <IncludeRemoteExecutor>true</IncludeRemoteExecutor>
  </PropertyGroup>
@@ -17,6 +17,7 @@
  <Compile Include="TarFile\TarFile.ExtractToDirectoryAsync.File.Tests.cs" />
  <Compile Include="TarFile\TarFile.CreateFromDirectoryAsync.Stream.Tests.cs" />
  <Compile Include="TarFile\TarFile.CreateFromDirectoryAsync.File.Tests.cs" />
+ <Compile Include="TarFile\TarFile.CreateFromDirectory.File.Roundtrip.cs" />
  <Compile Include="TarEntry\TarEntry.Conversion.Tests.Base.cs" />
  <Compile Include="TarEntry\GnuTarEntry.Conversion.Tests.cs" />
  <Compile Include="TarEntry\PaxTarEntry.Conversion.Tests.cs" />

src/libraries/System.Formats.Tar/tests/TarFile/TarFile.CreateFromDirectory.File.Roundtrip.cs

@@ -0,0 +1,79 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.IO;
+using Xunit;
+
+namespace System.Formats.Tar.Tests
+{
+ public class TarFile_CreateFromDirectory_Roundtrip_Tests : TarTestsBase
+ {
+ [ConditionalTheory(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
+ [InlineData("./file.txt", "subDirectory")]
+ [InlineData("../file.txt", "subDirectory")]
+ [InlineData("../file.txt", "subDirectory1/subDirectory1.1")]
+ [InlineData("./file.txt", "subDirectory1/subDirectory1.1")]
+ [InlineData("./file.txt", null)]
+ public void SymlinkRelativeTargets_InsideTheArchive_RoundtripsSuccessfully(string symlinkTargetPath, string subDirectory)
+ {
+ using TempDirectory root = new TempDirectory();
+
+ string destinationArchive = Path.Join(root.Path, "destination.tar");
+
+ string sourceDirectoryName = Path.Join(root.Path, "baseDirectory");
+ Directory.CreateDirectory(sourceDirectoryName);
+
+ string destinationDirectoryName = Path.Join(root.Path, "destinationDirectory");
+ Directory.CreateDirectory(destinationDirectoryName);
+
+ string sourceSubDirectory = Path.Join(sourceDirectoryName, subDirectory);
+ if(subDirectory != null) Directory.CreateDirectory(sourceSubDirectory);
+
+ File.Create(Path.Join(sourceDirectoryName, subDirectory, symlinkTargetPath)).Dispose();
+ File.CreateSymbolicLink(Path.Join(sourceSubDirectory, "linkToFile"), symlinkTargetPath);
+
+ TarFile.CreateFromDirectory(sourceDirectoryName, destinationArchive, includeBaseDirectory: false);
+
+ using FileStream archiveStream = File.OpenRead(destinationArchive);
+ TarFile.ExtractToDirectory(archiveStream, destinationDirectoryName, overwriteFiles: true);
+
+ string destinationSubDirectory = Path.Join(destinationDirectoryName, subDirectory);
+ string symlinkPath = Path.Join(destinationSubDirectory, "linkToFile");
+ Assert.True(File.Exists(symlinkPath));
+
+ FileInfo? fileInfo = new(symlinkPath);
+ Assert.Equal(symlinkTargetPath, fileInfo.LinkTarget);
+
+ FileSystemInfo? symlinkTarget = File.ResolveLinkTarget(symlinkPath, returnFinalTarget: true);
+ Assert.True(File.Exists(symlinkTarget.FullName));
+ }
+
+ [ConditionalTheory(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
+ [InlineData("../file.txt", null)]
+ [InlineData("../../file.txt", "subDirectory")]
+ public void SymlinkRelativeTargets_OutsideTheArchive_Fails(string symlinkTargetPath, string subDirectory)
+ {
+ using TempDirectory root = new TempDirectory();
+
+ string destinationArchive = Path.Join(root.Path, "destination.tar");
+
+ string sourceDirectoryName = Path.Join(root.Path, "baseDirectory");
+ Directory.CreateDirectory(sourceDirectoryName);
+
+ string destinationDirectoryName = Path.Join(root.Path, "destinationDirectory");
+ Directory.CreateDirectory(destinationDirectoryName);
+
+ string sourceSubDirectory = Path.Join(sourceDirectoryName, subDirectory);
+ if(subDirectory != null) Directory.CreateDirectory(sourceSubDirectory);
+
+ File.CreateSymbolicLink(Path.Join(sourceSubDirectory, "linkToFile"), symlinkTargetPath);
+
+ TarFile.CreateFromDirectory(sourceDirectoryName, destinationArchive, includeBaseDirectory: false);
+
+ using FileStream archiveStream = File.OpenRead(destinationArchive);
+ Exception exception = Assert.Throws<IOException>(() => TarFile.ExtractToDirectory(archiveStream, destinationDirectoryName, overwriteFiles: true));
+
+ Assert.Equal(SR.Format(SR.TarExtractingResultsLinkOutside, symlinkTargetPath, destinationDirectoryName), exception.Message);
+ }
+ }
+}

src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectoryAsync.Stream.Tests.cs

@@ -110,6 +110,29 @@ public async Task ExtractEntry_DockerImageTarWithFileTypeInDirectoriesInMode_Suc
  }
  }
 
+ [ConditionalFact(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
+ public async Task ExtractEntry_PodmanImageTarWithRelativeSymlinksPointingInExtractDirectory_SuccessfullyExtracts_Async()
+ {
+ using (TempDirectory root = new TempDirectory())
+ {
+ await using MemoryStream archiveStream = GetTarMemoryStream(CompressionMethod.Uncompressed, "misc", "podman-hello-world");
+ await TarFile.ExtractToDirectoryAsync(archiveStream, root.Path, overwriteFiles: true);
+
+ Assert.True(File.Exists(Path.Join(root.Path, "manifest.json")));
+ Assert.True(File.Exists(Path.Join(root.Path, "repositories")));
+ Assert.True(File.Exists(Path.Join(root.Path, "efb53921da3394806160641b72a2cbd34ca1a9a8345ac670a85a04ad3d0e3507.tar")));
+
+ string symlinkPath = Path.Join(root.Path, "e7fc2b397c1ab5af9938f18cc9a80d526cccd1910e4678390157d8cc6c94410d/layer.tar");
+ Assert.True(File.Exists(symlinkPath));
+
+ FileInfo? fileInfo = new(symlinkPath);
+ Assert.Equal("../efb53921da3394806160641b72a2cbd34ca1a9a8345ac670a85a04ad3d0e3507.tar", fileInfo.LinkTarget);
+
+ FileSystemInfo? symlinkTarget = File.ResolveLinkTarget(symlinkPath, returnFinalTarget: true);
+ Assert.True(File.Exists(symlinkTarget.FullName));
+ }
+ }
+
  [Theory]
  [InlineData(TarEntryType.SymbolicLink)]
  [InlineData(TarEntryType.HardLink)]