2 files changed, 112 insertions, 0 deletions
diff --git a/tests/Jellyfin.Controller.Tests/IO/FileSystemHelperTests.cs b/tests/Jellyfin.Controller.Tests/IO/FileSystemHelperTests.cs
new file mode 100644
index 0000000000..4c7addd164
--- /dev/null
+++ b/tests/Jellyfin.Controller.Tests/IO/FileSystemHelperTests.cs
@@ -0,0 +1,60 @@
+using System;
+using System.IO;
+using MediaBrowser.Controller.IO;
+using Xunit;
+
+namespace Jellyfin.Controller.Tests.IO;
+
+public class FileSystemHelperTests
+{
+    private static readonly string _parentPath = Path.Combine(Path.GetTempPath(), "jellyfin-test", "root", "default");
+
+    [Theory]
+    [InlineData("Movies")]
+    [InlineData("My Movies")]
+    [InlineData("..2")]
+    [InlineData("...")]
+    [InlineData("a.b")]
+    public void GetChildPath_ValidName_ReturnsPathInsideParent(string name)
+    {
+        var path = FileSystemHelper.GetChildPath(_parentPath, name);
+
+        Assert.Equal(Path.Combine(_parentPath, name), path);
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("   ")]
+    [InlineData(".")]
+    [InlineData("..")]
+    [InlineData("../..")]
+    [InlineData("../../etc")]
+    [InlineData("Movies/../..")]
+    [InlineData("/var/lib/jellyfin/data")]
+    [InlineData("sub/folder")]
+    [InlineData("with\0null")]
+    public void GetChildPath_EscapingName_ReturnsNull(string name)
+    {
+        Assert.Null(FileSystemHelper.GetChildPath(_parentPath, name));
+    }
+
+    [Theory]
+    [InlineData("..\\..")]
+    [InlineData("sub\\folder")]
+    [InlineData("C:\\Windows")]
+    public void GetChildPath_WindowsSeparator_DoesNotEscapeParent(string name)
+    {
+        var path = FileSystemHelper.GetChildPath(_parentPath, name);
+
+        // On Windows these are rejected outright, on other platforms a backslash is a legal file name character.
+        Assert.True(path is null || string.Equals(Path.GetDirectoryName(path), _parentPath, StringComparison.Ordinal));
+    }
+
+    [Fact]
+    public void GetChildPath_ParentWithTrailingSeparator_ReturnsPathInsideParent()
+    {
+        var path = FileSystemHelper.GetChildPath(_parentPath + Path.DirectorySeparatorChar, "Movies");
+
+        Assert.Equal(Path.Combine(_parentPath, "Movies"), path);
+    }
+}
diff --git a/tests/Jellyfin.Server.Integration.Tests/Controllers/LibraryStructureControllerTests.cs b/tests/Jellyfin.Server.Integration.Tests/Controllers/LibraryStructureControllerTests.cs
index 2de6408cc6..0a5838c545 100644
--- a/tests/Jellyfin.Server.Integration.Tests/Controllers/LibraryStructureControllerTests.cs
+++ b/tests/Jellyfin.Server.Integration.Tests/Controllers/LibraryStructureControllerTests.cs
@@ -114,6 +114,58 @@ public sealed class LibraryStructureControllerTests : IClassFixture<JellyfinAppl
         Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
     }
 
+    [Theory]
+    [Priority(1)]
+    [InlineData("..")]
+    [InlineData("../..")]
+    [InlineData(".")]
+    [InlineData("test/../..")]
+    [InlineData("/var/lib/jellyfin/data")]
+    public async Task DeleteLibrary_PathTraversal_NotFound(string name)
+    {
+        var client = _factory.CreateClient();
+        client.DefaultRequestHeaders.AddAuthHeader(_accessToken ??= await AuthHelper.CompleteStartupAsync(client));
+
+        using var response = await client.DeleteAsync($"Library/VirtualFolders?name={Uri.EscapeDataString(name)}", TestContext.Current.CancellationToken);
+        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
+    }
+
+    [Theory]
+    [Priority(1)]
+    [InlineData("..")]
+    [InlineData("../..")]
+    [InlineData(".")]
+    [InlineData("test/../..")]
+    [InlineData("/var/lib/jellyfin/data")]
+    public async Task RenameLibrary_PathTraversalNewName_BadRequest(string newName)
+    {
+        var client = _factory.CreateClient();
+        client.DefaultRequestHeaders.AddAuthHeader(_accessToken ??= await AuthHelper.CompleteStartupAsync(client));
+
+        using var response = await client.PostAsync(
+            $"Library/VirtualFolders/Name?name=test&newName={Uri.EscapeDataString(newName)}",
+            null,
+            TestContext.Current.CancellationToken);
+        Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+    }
+
+    [Theory]
+    [Priority(1)]
+    [InlineData("..")]
+    [InlineData("../..")]
+    [InlineData("/var/lib/jellyfin/data")]
+    public async Task RenameLibrary_PathTraversalName_NotFound(string name)
+    {
+        var client = _factory.CreateClient();
+        client.DefaultRequestHeaders.AddAuthHeader(_accessToken ??= await AuthHelper.CompleteStartupAsync(client));
+
+        using var response = await client.PostAsync(
+            $"Library/VirtualFolders/Name?name={Uri.EscapeDataString(name)}&newName=renamed",
+            null,
+            TestContext.Current.CancellationToken);
+        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
+    }
+
     [Fact]
     [Priority(1)]
     public async Task DeleteLibrary_Valid_Success()