[AvPlayer] Resolve guest media within app0 (#347)

Handle project-relative file URIs through the guest app0 mount, including unambiguous case-insensitive lookup for case-sensitive hosts. Reject host paths, traversal underflow, malformed or remote URIs, and symlink/reparse escapes; cover accepted app0 forms and sandbox boundaries with nonparallel tests.
2026-07-22 19:06:15 +08:00 · 2026-07-17 19:42:30 -04:00
parent 3c500d2cf0
commit 22bbb4e909
2 changed files with 404 additions and 11 deletions
@@ -0,0 +1,154 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.Libs.AvPlayer;
+using Xunit;
+
+namespace SharpEmu.Libs.Tests.AvPlayer;
+
+[CollectionDefinition("AvPlayerPathState", DisableParallelization = true)]
+public sealed class AvPlayerPathStateCollection;
+
+[Collection("AvPlayerPathState")]
+public sealed class AvPlayerPathTests : IDisposable
+{
+    private readonly string? _originalApp0;
+    private readonly string _tempRoot;
+    private readonly string _app0Root;
+
+    public AvPlayerPathTests()
+    {
+        _originalApp0 = Environment.GetEnvironmentVariable("SHARPEMU_APP0_DIR");
+        _tempRoot = Path.Combine(
+            Path.GetTempPath(),
+            $"sharpemu-avplayer-{Guid.NewGuid():N}");
+        _app0Root = Path.Combine(_tempRoot, "app0");
+        Directory.CreateDirectory(_app0Root);
+        Environment.SetEnvironmentVariable("SHARPEMU_APP0_DIR", _app0Root);
+    }
+
+    [Fact]
+    public void UnrealRelativeFileUriAnchorsAtApp0AndResolvesMedia()
+    {
+        var mediaPath = CreateFile("Project/Content/Movies/Intro.mp4");
+
+        var resolved = AvPlayerExports.ResolveGuestPath(
+            "file://../../../Project/Content/Movies/Intro.mp4");
+
+        Assert.NotNull(resolved);
+        Assert.Equal(File.ReadAllBytes(mediaPath), File.ReadAllBytes(resolved));
+        AssertPathIsInsideApp0(resolved);
+    }
+
+    [Fact]
+    public void RelativeFileUriCannotEscapeApp0()
+    {
+        var outsidePath = Path.Combine(_tempRoot, "outside.mp4");
+        File.WriteAllBytes(outsidePath, [0x7F]);
+
+        var resolved = AvPlayerExports.ResolveGuestPath("file://../outside.mp4");
+
+        Assert.Null(resolved);
+        Assert.Null(AvPlayerExports.ResolveGuestPath("file://%2e%2e/outside.mp4"));
+        Assert.Null(AvPlayerExports.ResolveGuestPath("app0:/../../outside.mp4"));
+        Assert.Null(AvPlayerExports.ResolveGuestPath("file://..%2foutside.mp4"));
+        Assert.Null(AvPlayerExports.ResolveGuestPath("file://../outside.mp4?query"));
+        Assert.Null(AvPlayerExports.ResolveGuestPath("file://../outside%ZZ.mp4"));
+        Assert.Null(AvPlayerExports.ResolveGuestPath("file://../outside%00.mp4"));
+    }
+
+    [Fact]
+    public void AbsoluteHostPathsCannotBypassApp0()
+    {
+        var outsidePath = Path.Combine(_tempRoot, "outside.mp4");
+        File.WriteAllBytes(outsidePath, [0x7F]);
+
+        Assert.Null(AvPlayerExports.ResolveGuestPath(outsidePath));
+        Assert.Null(AvPlayerExports.ResolveGuestPath(new Uri(outsidePath).AbsoluteUri));
+    }
+
+    [Fact]
+    public void NonFileUrisAndApp0LookalikesAreRejected()
+    {
+        CreateFile("evil/intro.mp4");
+
+        Assert.Null(AvPlayerExports.ResolveGuestPath("https://example.test/intro.mp4"));
+        Assert.Null(AvPlayerExports.ResolveGuestPath("file://server/share/intro.mp4"));
+        Assert.Null(AvPlayerExports.ResolveGuestPath("/app0evil/intro.mp4"));
+    }
+
+    [Fact]
+    public void SymlinkCannotEscapeApp0()
+    {
+        if (OperatingSystem.IsWindows())
+        {
+            return;
+        }
+
+        var outsideDirectory = Path.Combine(_tempRoot, "outside");
+        Directory.CreateDirectory(outsideDirectory);
+        File.WriteAllBytes(Path.Combine(outsideDirectory, "secret.mp4"), [0x7F]);
+        Directory.CreateSymbolicLink(
+            Path.Combine(_app0Root, "linked"),
+            outsideDirectory);
+
+        Assert.Null(AvPlayerExports.ResolveGuestPath("app0:/linked/secret.mp4"));
+    }
+
+    [Fact]
+    public void App0UriStillResolvesMedia()
+    {
+        var mediaPath = CreateFile("movies/intro.mp4");
+
+        var resolved = AvPlayerExports.ResolveGuestPath("app0:/movies/intro.mp4");
+
+        Assert.Equal(Path.GetFullPath(mediaPath), resolved);
+        Assert.Equal(
+            Path.GetFullPath(mediaPath),
+            AvPlayerExports.ResolveGuestPath("movies/intro.mp4"));
+        Assert.Equal(
+            Path.GetFullPath(mediaPath),
+            AvPlayerExports.ResolveGuestPath("file:///app0/movies/intro.mp4"));
+        Assert.Equal(
+            Path.GetFullPath(mediaPath),
+            AvPlayerExports.ResolveGuestPath("app0:movies/intro.mp4"));
+    }
+
+    [Fact]
+    public void GuestMediaLookupIsCaseInsensitiveOnCaseSensitiveHosts()
+    {
+        var mediaPath = CreateFile("project/content/movies/intro.mp4");
+
+        var resolved = AvPlayerExports.ResolveGuestPath(
+            "file://../../../PROJECT/CONTENT/MOVIES/INTRO.MP4");
+
+        Assert.NotNull(resolved);
+        Assert.Equal(File.ReadAllBytes(mediaPath), File.ReadAllBytes(resolved));
+        AssertPathIsInsideApp0(resolved);
+    }
+
+    public void Dispose()
+    {
+        Environment.SetEnvironmentVariable("SHARPEMU_APP0_DIR", _originalApp0);
+        Directory.Delete(_tempRoot, recursive: true);
+    }
+
+    private string CreateFile(string relativePath)
+    {
+        var path = Path.Combine(_app0Root, relativePath);
+        Directory.CreateDirectory(Path.GetDirectoryName(path)!);
+        File.WriteAllBytes(path, [0x01, 0x02, 0x03]);
+        return path;
+    }
+
+    private void AssertPathIsInsideApp0(string resolved)
+    {
+        var rootWithSeparator =
+            Path.TrimEndingDirectorySeparator(Path.GetFullPath(_app0Root)) +
+            Path.DirectorySeparatorChar;
+        Assert.StartsWith(
+            rootWithSeparator,
+            Path.GetFullPath(resolved),
+            StringComparison.OrdinalIgnoreCase);
+    }
+}