Merge pull request #2037 from giuseppe/fix-decoding-xattr

chunked, composefs: fix decoding of xattrs

pkg/chunked/dump/dump.go

@@ -4,6 +4,7 @@ package dump
 
 import (
 	"bufio"
+	"encoding/base64"
 	"fmt"
 	"io"
 	"path/filepath"
@@ -22,12 +23,12 @@ const (
 	ESCAPE_LONE_DASH
 )
 
-func escaped(val string, escape int) string {
+func escaped(val []byte, escape int) string {
 	noescapeSpace := escape&NOESCAPE_SPACE != 0
 	escapeEqual := escape&ESCAPE_EQUAL != 0
 	escapeLoneDash := escape&ESCAPE_LONE_DASH != 0
 
-	if escapeLoneDash && val == "-" {
+	if escapeLoneDash && len(val) == 1 && val[0] == '-' {
 		return fmt.Sprintf("\\x%.2x", val[0])
 	}
 
@@ -75,8 +76,8 @@ func escaped(val string, escape int) string {
 	return result
 }
 
-func escapedOptional(val string, escape int) string {
+func escapedOptional(val []byte, escape int) string {
-	if val == "" {
+	if len(val) == 0 {
 		return "-"
 	}
 	return escaped(val, escape)
@@ -136,7 +137,7 @@ func dumpNode(out io.Writer, added map[string]*internal.FileMetadata, links map[
 	}
 	added[path] = entry
 
-	if _, err := fmt.Fprint(out, escaped(path, ESCAPE_STANDARD)); err != nil {
+	if _, err := fmt.Fprint(out, escaped([]byte(path), ESCAPE_STANDARD)); err != nil {
 		return err
 	}
 
@@ -180,7 +181,7 @@ func dumpNode(out io.Writer, added map[string]*internal.FileMetadata, links map[
 		}
 	}
 
-	if _, err := fmt.Fprint(out, escapedOptional(payload, ESCAPE_LONE_DASH)); err != nil {
+	if _, err := fmt.Fprint(out, escapedOptional([]byte(payload), ESCAPE_LONE_DASH)); err != nil {
 		return err
 	}
 
@@ -194,14 +195,18 @@ func dumpNode(out io.Writer, added map[string]*internal.FileMetadata, links map[
 		return err
 	}
 	digest := verityDigests[payload]
-	if _, err := fmt.Fprint(out, escapedOptional(digest, ESCAPE_LONE_DASH)); err != nil {
+	if _, err := fmt.Fprint(out, escapedOptional([]byte(digest), ESCAPE_LONE_DASH)); err != nil {
 		return err
 	}
 
-	for k, v := range entry.Xattrs {
+	for k, vEncoded := range entry.Xattrs {
-		name := escaped(k, ESCAPE_EQUAL)
+		v, err := base64.StdEncoding.DecodeString(vEncoded)
-		value := escaped(v, ESCAPE_EQUAL)
+		if err != nil {
+			return fmt.Errorf("decode xattr %q: %w", k, err)
+		}
+		name := escaped([]byte(k), ESCAPE_EQUAL)
 
+		value := escaped(v, ESCAPE_EQUAL)
 		if _, err := fmt.Fprintf(out, " %s=%s", name, value); err != nil {
 			return err
 		}

pkg/chunked/dump/dump_test.go

@@ -4,6 +4,7 @@ package dump
 
 import (
 	"bytes"
+	"encoding/base64"
 	"testing"
 	"time"
 
@@ -37,7 +38,7 @@ func TestEscaped(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.input, func(t *testing.T) {
-			result := escaped(test.input, test.escape)
+			result := escaped([]byte(test.input), test.escape)
 			if result != test.want {
 				t.Errorf("got %q, want %q", result, test.want)
 			}
@@ -60,7 +61,7 @@ func TestDumpNode(t *testing.T) {
 		Linkname: "",
 		Digest:   "sha256:abcdef1234567890",
 		Xattrs: map[string]string{
-			"user.key1": "value1",
+			"user.key1": base64.StdEncoding.EncodeToString([]byte("value1")),
 		},
 	}
 
@@ -86,7 +87,7 @@ func TestDumpNode(t *testing.T) {
 		ModTime:  &modTime,
 		Linkname: "",
 		Xattrs: map[string]string{
-			"user.key2": "value2",
+			"user.key2": base64.StdEncoding.EncodeToString([]byte("value2")),
 		},
 	}
 
@@ -226,6 +227,5 @@ func TestDumpNode(t *testing.T) {
 				t.Errorf("for %s, got %q, want %q", testCase.name, actual, testCase.expected)
 			}
 		}
-
 	}
 }