Logging: strip new lines and other control characters (prysmaticlabs#…

…11185)

* Logging: strip new lines and other control characters

* Use strings.Map and only sanitize the field value

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>

runtime/logging/logrus-prefixed-formatter/formatter.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 	"sync"
 	"time"
+	"unicode"
 
 	"github.com/mgutz/ansi"
 	"github.com/sirupsen/logrus"
@@ -294,16 +295,29 @@ func (f *TextFormatter) printColored(b *bytes.Buffer, entry *logrus.Entry, keys
 	for _, k := range keys {
 		if k != "prefix" {
 			v := entry.Data[k]
-			format := " %s=%+v"
+
+			format := "%+v"
 			if k == logrus.ErrorKey {
-				format = " %s=%v" // To avoid printing stack traces for errors
+				format = "%v" // To avoid printing stack traces for errors
 			}
-			_, err = fmt.Fprintf(b, format, levelColor(k), v)
+
+			// Sanitize field values to remove new lines and other control characters.
+			s := sanitize(fmt.Sprintf(format, v))
+			_, err = fmt.Fprintf(b, " %s=%s", levelColor(k), s)
 		}
 	}
 	return
 }
 
+func sanitize(s string) string {
+	return strings.Map(func(r rune) rune {
+		if unicode.IsControl(r) {
+			return -1
+		}
+		return r
+	}, s)
+}
+
 func (f *TextFormatter) needsQuoting(text string) bool {
 	if f.QuoteEmptyFields && len(text) == 0 {
 		return true

runtime/logging/logrus-prefixed-formatter/formatter_test.go

@@ -71,3 +71,15 @@ func TestFormatter_SuppressErrorStackTraces(t *testing.T) {
 	log.WithError(errors.Wrap(errFn(), "outer")).Error("test")
 	require.Equal(t, true, regexp.MustCompile(`test error=outer: inner\n\s*$`).MatchString(output.GetValue()), fmt.Sprintf("wrong log output: %s", output.GetValue()))
 }
+
+func TestFormatter_EscapesControlCharacters(t *testing.T) {
+	formatter := new(TextFormatter)
+	formatter.ForceFormatting = true
+	log := logrus.New()
+	log.Formatter = formatter
+	output := new(LogOutput)
+	log.Out = output
+
+	log.WithField("test", "foo\nbar").Error("testing things")
+	require.Equal(t, "[0000] ERROR testing things test=foobar"+"\n", output.GetValue())
+}