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Workaround libgit2 safe.directory case mismatch bug #1899

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159 changes: 157 additions & 2 deletions GVFS/GVFS.Common/Git/LibGit2Repo.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,8 @@ public class LibGit2Repo : IDisposable
{
private bool disposedValue = false;

public delegate void MultiVarConfigCallback(string value);

public LibGit2Repo(ITracer tracer, string repoPath)
{
this.Tracer = tracer;
Expand All @@ -23,8 +25,12 @@ public LibGit2Repo(ITracer tracer, string repoPath)
string message = "Couldn't open repo at " + repoPath + ": " + reason;
tracer.RelatedWarning(message);

Native.Shutdown();
throw new InvalidDataException(message);
if (!reason.EndsWith(" is not owned by current user")
|| !CheckSafeDirectoryConfigForCaseSensitivityIssue(tracer, repoPath, out repoHandle))
{
Native.Shutdown();
throw new InvalidDataException(message);
}
}

this.RepoHandle = repoHandle;
Expand Down Expand Up @@ -246,7 +252,64 @@ public virtual string GetConfigString(string name)
{
Native.Config.Free(configHandle);
}
}

public void ForEachMultiVarConfig(string key, MultiVarConfigCallback callback)
{
if (Native.Config.GetConfig(out IntPtr configHandle, this.RepoHandle) != Native.ResultCode.Success)
{
throw new LibGit2Exception($"Failed to get config handle: {Native.GetLastError()}");
}
try
{
ForEachMultiVarConfig(configHandle, key, callback);
}
finally
{
Native.Config.Free(configHandle);
}
}

public static void ForEachMultiVarConfigInGlobalAndSystemConfig(string key, MultiVarConfigCallback callback)
{
if (Native.Config.GetGlobalAndSystemConfig(out IntPtr configHandle) != Native.ResultCode.Success)
{
throw new LibGit2Exception($"Failed to get global and system config handle: {Native.GetLastError()}");
}
try
{
ForEachMultiVarConfig(configHandle, key, callback);
}
finally
{
Native.Config.Free(configHandle);
}
}

private static void ForEachMultiVarConfig(IntPtr configHandle, string key, MultiVarConfigCallback callback)
{
Native.Config.GitConfigMultivarCallback nativeCallback = (entryPtr, payload) =>
{
try
{
var entry = Marshal.PtrToStructure<Native.Config.GitConfigEntry>(entryPtr);
callback(entry.GetValue());
}
catch (Exception)
{
return Native.ResultCode.Failure;
}
return 0;
};
if (Native.Config.GetMultivarForeach(
configHandle,
key,
regex:"",
nativeCallback,
IntPtr.Zero) != Native.ResultCode.Success)
{
throw new LibGit2Exception($"Failed to get multivar config for '{key}': {Native.GetLastError()}");
}
}

/// <summary>
Expand Down Expand Up @@ -302,11 +365,48 @@ protected virtual void Dispose(bool disposing)
}
}

private bool CheckSafeDirectoryConfigForCaseSensitivityIssue(ITracer tracer, string repoPath, out IntPtr repoHandle)
{
/* Libgit2 has a bug where it is case sensitive for safe.directory (especially the
* drive letter) when git.exe isn't. Until a fix can be made and propagated, work
* around it by matching the repo path we request to the configured safe directory.
*
* See https://github.com/libgit2/libgit2/issues/7037
*/
repoHandle = IntPtr.Zero;

string NormalizePath(string path)
{
if (string.IsNullOrEmpty(path))
{
return path;
}

string normalized = path.Replace('\\', '/').ToUpperInvariant();
return normalized.TrimEnd('/');
}

string normalizedRequestedPath = NormalizePath(repoPath);

string configuredMatchingDirectory = null;
ForEachMultiVarConfigInGlobalAndSystemConfig("safe.directory", (string value) =>
{
string normalizedConfiguredPath = NormalizePath(value);
if (normalizedConfiguredPath == normalizedRequestedPath)
{
configuredMatchingDirectory = value;
}
});

return configuredMatchingDirectory != null && Native.Repo.Open(out repoHandle, configuredMatchingDirectory) == Native.ResultCode.Success;
}

public static class Native
{
public enum ResultCode : int
{
Success = 0,
Failure = -1,
NotFound = -3,
}

Expand Down Expand Up @@ -370,9 +470,64 @@ public static class Config
[DllImport(Git2NativeLibName, EntryPoint = "git_repository_config")]
public static extern ResultCode GetConfig(out IntPtr configHandle, IntPtr repoHandle);

[DllImport(Git2NativeLibName, EntryPoint = "git_config_open_default")]
public static extern ResultCode GetGlobalAndSystemConfig(out IntPtr configHandle);

[DllImport(Git2NativeLibName, EntryPoint = "git_config_get_string")]
public static extern ResultCode GetString(out string value, IntPtr configHandle, string name);

[DllImport(Git2NativeLibName, EntryPoint = "git_config_get_multivar_foreach")]
public static extern ResultCode GetMultivarForeach(
IntPtr configHandle,
string name,
string regex,
GitConfigMultivarCallback callback,
IntPtr payload);

[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
public delegate ResultCode GitConfigMultivarCallback(
IntPtr entryPtr,
IntPtr payload);

[StructLayout(LayoutKind.Sequential)]
public struct GitConfigEntry
{
public IntPtr Name;
public IntPtr Value;
public IntPtr BackendType;
public IntPtr OriginPath;
public uint IncludeDepth;
public int Level;

public string GetValue()
{
return Value != IntPtr.Zero ? MarshalUtf8String(Value) : null;
}

public string GetName()
{
return Name != IntPtr.Zero ? MarshalUtf8String(Name) : null;
}

private static string MarshalUtf8String(IntPtr ptr)
{
if (ptr == IntPtr.Zero)
{
return null;
}

int length = 0;
while (Marshal.ReadByte(ptr, length) != 0)
{
length++;
}

byte[] buffer = new byte[length];
Marshal.Copy(ptr, buffer, 0, length);
return System.Text.Encoding.UTF8.GetString(buffer);
}
}

[DllImport(Git2NativeLibName, EntryPoint = "git_config_get_bool")]
public static extern ResultCode GetBool(out bool value, IntPtr configHandle, string name);

Expand Down
1 change: 1 addition & 0 deletions GVFS/GVFS.FunctionalTests/GVFS.FunctionalTests.csproj
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@
<ProjectReference Include="..\GVFS.NativeTests\GVFS.NativeTests.vcxproj">
<ReferenceOutputAssembly>false</ReferenceOutputAssembly>
</ProjectReference>
<ProjectReference Include="..\GVFS.UnitTests\GVFS.UnitTests.csproj" />
<None Include="$(RepoOutPath)GVFS.NativeTests\bin\x64\$(Configuration)\GVFS.NativeTests.dll">
<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
</None>
Expand Down
7 changes: 7 additions & 0 deletions GVFS/GVFS.FunctionalTests/Program.cs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
using GVFS.FunctionalTests.Properties;
using GVFS.FunctionalTests.Tools;
using GVFS.PlatformLoader;
using GVFS.Tests;
using System;
using System.Collections.Generic;
Expand All @@ -13,6 +14,7 @@ public class Program
public static void Main(string[] args)
{
Properties.Settings.Default.Initialize();
GVFSPlatformLoader.Initialize();
Console.WriteLine("Settings.Default.CurrentDirectory: {0}", Settings.Default.CurrentDirectory);
Console.WriteLine("Settings.Default.PathToGit: {0}", Settings.Default.PathToGit);
Console.WriteLine("Settings.Default.PathToGVFS: {0}", Settings.Default.PathToGVFS);
Expand All @@ -21,6 +23,11 @@ public static void Main(string[] args)
NUnitRunner runner = new NUnitRunner(args);
runner.AddGlobalSetupIfNeeded("GVFS.FunctionalTests.GlobalSetup");

if (runner.HasCustomArg("--debug"))
{
Debugger.Launch();
}

if (runner.HasCustomArg("--no-shared-gvfs-cache"))
{
Console.WriteLine("Running without a shared git object cache");
Expand Down
119 changes: 119 additions & 0 deletions GVFS/GVFS.FunctionalTests/Tests/EnlistmentPerTestCase/SafeDirectoryOwnershipTests.cs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,119 @@
using GVFS.Common;
using GVFS.Common.Git;
using GVFS.Common.Tracing;
using GVFS.FunctionalTests.Tools;
using GVFS.UnitTests.Category;
using NUnit.Framework;
using System;
using System.IO;
using System.Security.AccessControl;
using System.Security.Principal;

namespace GVFS.FunctionalTests.Tests.EnlistmentPerTestCase
{
[TestFixture]
/* Not inheriting from TestsWithEnlistmentPerTestCase because we don't need to mount
* the repo for this test. */
public class SafeDirectoryOwnershipTests
{
private GVFSEnlistment Enlistment;
private static readonly SecurityIdentifier usersSid = new SecurityIdentifier(WellKnownSidType.BuiltinUsersSid, null);

[SetUp]
public void SetUp()
{
var enlistmentRoot = GVFSFunctionalTestEnlistment.GetUniqueEnlistmentRoot();
Enlistment = new GVFSEnlistment(
enlistmentRoot,
GVFSTestConfig.RepoToClone,
GVFSPlatform.Instance.GitInstallation.GetInstalledGitBinPath(),
authentication: null);
var process = Enlistment.CreateGitProcess();
Common.Git.GitProcess.Init(Enlistment);
}

[TestCase]
public void RepoOpensIfSafeDirectoryConfigIsSet()
{
var repoDir = this.Enlistment.WorkingDirectoryBackingRoot;
using (var safeDirectoryConfig = WithSafeDirectoryConfig(repoDir))
using (var enlistmentOwner = WithEnlistmentOwner(usersSid))
using (LibGit2Repo repo = new LibGit2Repo(NullTracer.Instance, repoDir))
{
// repo is opened in the constructor
}
}

[TestCase(true)]
[TestCase(false)]
[Category(CategoryConstants.CaseInsensitiveFileSystemOnly)]
public void RepoOpensEvenIfSafeDirectoryConfigIsCaseMismatched(bool upperCase)
{
var repoDir = this.Enlistment.WorkingDirectoryBackingRoot;

if (upperCase)
{
repoDir = repoDir.ToUpperInvariant();
}
else
{
repoDir = repoDir.ToLowerInvariant();
}
using (var safeDirectoryConfig = WithSafeDirectoryConfig(this.Enlistment.WorkingDirectoryBackingRoot))
using (var enlistmentOwner = WithEnlistmentOwner(usersSid))
using (LibGit2Repo repo = new LibGit2Repo(NullTracer.Instance, repoDir))
{
// repo is opened in the constructor
}
}

private class Disposable : IDisposable
{
private readonly Action onDispose;

public Disposable(Action onDispose)
{
this.onDispose = onDispose;
}

public void Dispose()
{
onDispose();
}
}

private IDisposable WithSafeDirectoryConfig(string repoDir)
{
Tools.GitProcess.Invoke(null, $"config --global --add safe.directory \"{repoDir}\"");
return new Disposable(() =>
Tools.GitProcess.Invoke(null, $"config --global --unset safe.directory \"{repoDir}\""));
}

private IDisposable WithEnlistmentOwner(SecurityIdentifier newOwner)
{
var repoDir = this.Enlistment.WorkingDirectoryBackingRoot;
var currentOwner = GetDirectoryOwner(repoDir);

SetDirectoryOwner(repoDir, newOwner);
var updatedOwner = GetDirectoryOwner(repoDir);
return new Disposable(() =>
SetDirectoryOwner(repoDir, currentOwner));
}

private SecurityIdentifier GetDirectoryOwner(string directory)
{
DirectorySecurity repoSecurity = Directory.GetAccessControl(directory);
return (SecurityIdentifier)repoSecurity.GetOwner(typeof(SecurityIdentifier));
}

private void SetDirectoryOwner(string directory, SecurityIdentifier newOwner)
{
using (new PrivilegeEnabler(PrivilegeEnabler.AllowChangeOwnerToGroup))
{
DirectorySecurity repoSecurity = Directory.GetAccessControl(directory);
repoSecurity.SetOwner(newOwner);
Directory.SetAccessControl(directory, repoSecurity);
}
}
}
}
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