feat/backup

jar/backup.go

@@ -0,0 +1,57 @@
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package jar
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+// backupFile makes copies JARs file in the backup folder
+func backupFile(jarPath, jarSource, jarFile string) error {
+	pathdst := filepath.Join(jarPath, jarFile+".bak")
+
+	_, err := copyJars(jarSource, pathdst)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func copyJars(src, dst string) (int64, error) {
+	sourceFileStat, err := os.Stat(src)
+	if err != nil {
+		return 0, err
+	}
+
+	if m := sourceFileStat.Mode(); !m.IsRegular() {
+		return 0, fmt.Errorf("%s is not a regular file: %s", src, m)
+	}
+
+	source, err := os.Open(src)
+	if err != nil {
+		return 0, err
+	}
+	defer source.Close()
+
+	destination, err := os.Create(dst)
+	if err != nil {
+		return 0, err
+	}
+	defer destination.Close()
+	nBytes, err := io.Copy(destination, source)
+	return nBytes, err
+}

jar/walker.go

@@ -51,6 +51,8 @@ type Walker struct {
 	// Rewrite indicates if the Walker should rewrite JARs in place as it
 	// iterates through the filesystem.
 	Rewrite bool
+	// Backup indicates if the Walker should create a backups from JARs.
+	Backup bool
 	// SkipDir, if provided, allows the walker to skip certain directories
 	// as it scans.
 	SkipDir func(path string, de fs.DirEntry) bool
@@ -133,6 +135,7 @@ func (w *walker) skipDir(path string, d fs.DirEntry) bool {
 }
 
 func (w *walker) visit(p string, d fs.DirEntry) error {
+
 	if d.IsDir() || !d.Type().IsRegular() {
 		return nil
 	}
@@ -178,6 +181,13 @@ func (w *walker) visit(p string, d fs.DirEntry) error {
 		return nil
 	}
 
+	if w.Backup {
+		err := backupFile(w.dir, w.filepath(p), p)
+		if err != nil {
+			return fmt.Errorf("backup: %v", err)
+		}
+	}
+
 	dest := w.filepath(p)
 	// Ensure temp file is created in the same directory as the file we want to
 	// rewrite to improve the chances of ending up on the same filesystem. On
@@ -215,5 +225,6 @@ func (w *walker) visit(p string, d fs.DirEntry) error {
 		return fmt.Errorf("overwriting %s: %v", p, err)
 	}
 	w.handleRewrite(p, r)
+
 	return nil
 }

log4jscanner.go

@@ -40,6 +40,7 @@ Flags:
     -f, --force    Don't skip network and userland filesystems. (smb,nfs,afs,fuse)
     -w, --rewrite  Rewrite vulnerable JARs as they are detected.
     -v, --verbose  Print verbose logs to stderr.
+    -b, --backup   Make a backup of the scanned files
 
 `)
 }
@@ -49,8 +50,8 @@ var skipDirs = map[string]bool{
 	".git":         true,
 	"node_modules": true,
 	".idea":        true,
-	".svn":			true,
-	".p4root":		true,
+	".svn":         true,
+	".p4root":      true,
 
 	// TODO(ericchiang): expand
 }
@@ -63,6 +64,8 @@ func main() {
 		v       bool
 		force   bool
 		f       bool
+		backup  bool
+		b       bool
 		toSkip  []string
 	)
 	appendSkip := func(dir string) error {
@@ -76,6 +79,8 @@ func main() {
 	flag.BoolVar(&v, "v", false, "")
 	flag.BoolVar(&force, "force", false, "")
 	flag.BoolVar(&f, "f", false, "")
+	flag.BoolVar(&b, "b", false, "")
+	flag.BoolVar(&backup, "backup", false, "")
 	flag.Func("s", "", appendSkip)
 	flag.Func("skip", "", appendSkip)
 	flag.Usage = usage
@@ -94,6 +99,9 @@ func main() {
 	if w {
 		rewrite = w
 	}
+	if b {
+		backup = b
+	}
 	log.SetFlags(log.LstdFlags | log.Lshortfile)
 	logf := func(format string, v ...interface{}) {
 		if verbose {
@@ -103,6 +111,7 @@ func main() {
 	seen := 0
 	walker := jar.Walker{
 		Rewrite: rewrite,
+		Backup:  backup,
 		SkipDir: func(path string, d fs.DirEntry) bool {
 			seen++
 			if seen%5000 == 0 {