Git issue #5009 Asset cache can lead to denial of service if asset database is deleted -Fix

CHANGELOG-6.md

@@ -8,6 +8,14 @@ Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## Unreleased
 
+### 2024-02-01
+
+### Changed
+- The expandWithDuration in boltdb_manager to have a assetSHA dir cleanup.
+
+### Added
+- Added the cleanup in expander to clean the assetSHA in case of asset cache getting deleted
+
 ### Changed
 - Upgraded CI Go version to 1.21.3
 - Upgraded jwt version to 4.4.3

asset/boltdb_manager.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"github.com/spf13/viper"
 	"os"
 	"path/filepath"
 
@@ -23,6 +24,7 @@ const (
 	// ExpandDuration is the name of the prometheus summary vec used to track
 	// average latencies of asset expansion.
 	ExpandDuration = "sensu_go_asset_expand_duration"
+	FlagCacheDir   = "cache-dir"
 )
 
 var (
@@ -241,6 +243,15 @@ func (b *boltDBAssetManager) expandWithDuration(tmpFile *os.File, asset *corev2.
 	}))
 	defer timer.ObserveDuration()
 
+	assetSHA := asset.Sha512
+	CacheDir := viper.GetString(FlagCacheDir)
+	fullPath := filepath.Join(CacheDir, assetSHA)
+
+	if err := CleanUp(fullPath); err != nil {
+		logger.WithField("assetSHA path", fullPath).WithError(err).
+			Error("error cleaning up the assetSHA")
+	}
+
 	assetPath = filepath.Join(b.localStorage, asset.Sha512)
 	return assetPath, b.expander.Expand(tmpFile, assetPath)
 }

asset/expander.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
 
 	archiver "github.com/mholt/archiver/v3"
 
@@ -90,3 +91,13 @@ func sniffType(f io.ReadSeeker) (filetype_types.Type, error) {
 
 	return ft, nil
 }
+
+// cleanup of the assetSHA when cache dir gets force deleted
+func CleanUp(fullPath string) error {
+	errorSHA := os.RemoveAll(fullPath)
+	if errorSHA != nil {
+		return errorSHA
+	}
+	return nil
+
+}

asset/expander_test.go

@@ -113,3 +113,33 @@ func TestExpandInvalidArchive(t *testing.T) {
 		t.Fail()
 	}
 }
+
+// ---Test to check CleanUp
+func TestCleanUp(t *testing.T) {
+	t.Parallel()
+
+	// Create a temporary directory for testing
+	tmpDir := t.TempDir()
+
+	// Define the SHA and file name
+	SHAName := "shaAsset.tar"
+	SHAFilePath := filepath.Join(tmpDir, SHAName)
+
+	// Create a dummy file inside the temporary directory
+	SHAFile, err := os.Create(SHAFilePath)
+	if err != nil {
+		t.Fatalf("Failed to create dummy file: %v", err)
+	}
+	SHAFile.Close()
+
+	// Call CleanUp with the SHA of the dummy file and the temporary directory
+	err = CleanUp(SHAFilePath)
+	if err != nil {
+		t.Errorf("CleanUp returned an error: %v", err)
+	}
+
+	_, err = os.Stat(SHAFilePath)
+	if !os.IsNotExist(err) {
+		t.Errorf("CleanUp did not remove the dummy file as expected")
+	}
+}