Update ValidateMatcher in silence.go

Signed-off-by: George Robinson <george.robinson@grafana.com>

cmd/alertmanager/main.go

@@ -180,8 +180,8 @@ func run() int {
 		level.Error(logger).Log("msg", "error parsing the feature flag list", "err", err)
 		return 1
 	}
-
 	compat.InitFromFlags(logger, featureConfig)
+	silence.InitFromFlags(logger, featureConfig)
 
 	err = os.MkdirAll(*dataDir, 0o777)
 	if err != nil {

silence/silence.go

@@ -18,6 +18,7 @@ package silence
 import (
 	"bytes"
 	"fmt"
+	"github.com/prometheus/alertmanager/featurecontrol"
 	"io"
 	"math/rand"
 	"os"
@@ -26,6 +27,7 @@ import (
 	"sort"
 	"sync"
 	"time"
+	"unicode/utf8"
 
 	"github.com/benbjohnson/clock"
 	"github.com/go-kit/log"
@@ -469,6 +471,20 @@ func (s *Silences) GC() (int, error) {
 
 // ValidateMatcher runs validation on the matcher name, type, and pattern.
 var ValidateMatcher = func(m *pb.Matcher) error {
+	return validateClassicMatcher(m)
+}
+
+// InitFromFlags initializes the validation function from the flagger.
+func InitFromFlags(l log.Logger, f featurecontrol.Flagger) {
+	if !f.ClassicMatchersParsing() {
+		ValidateMatcher = func(m *pb.Matcher) error {
+			return validateUTF8Matcher(m)
+		}
+	}
+}
+
+// validateClassicMatcher validates the matcher against the classic rules.
+func validateClassicMatcher(m *pb.Matcher) error {
 	if !model.LabelName(m.Name).IsValid() {
 		return fmt.Errorf("invalid label name %q", m.Name)
 	}
@@ -487,6 +503,29 @@ var ValidateMatcher = func(m *pb.Matcher) error {
 	return nil
 }
 
+// validateUTF8Matcher validates the matcher against the UTF-8 rules.
+func validateUTF8Matcher(m *pb.Matcher) error {
+	if !utf8.ValidString(m.Name) {
+		return fmt.Errorf("invalid label name %q", m.Name)
+	}
+	switch m.Type {
+	case pb.Matcher_EQUAL, pb.Matcher_NOT_EQUAL:
+		if !utf8.ValidString(m.Pattern) {
+			return fmt.Errorf("invalid label value %q", m.Pattern)
+		}
+	case pb.Matcher_REGEXP, pb.Matcher_NOT_REGEXP:
+		if !utf8.ValidString(m.Pattern) {
+			return fmt.Errorf("invalid regular expression %q", m.Pattern)
+		}
+		if _, err := regexp.Compile(m.Pattern); err != nil {
+			return fmt.Errorf("invalid regular expression %q: %s", m.Pattern, err)
+		}
+	default:
+		return fmt.Errorf("unknown matcher type %q", m.Type)
+	}
+	return nil
+}
+
 func matchesEmpty(m *pb.Matcher) bool {
 	switch m.Type {
 	case pb.Matcher_EQUAL:

silence/silence_test.go

@@ -1114,7 +1114,7 @@ func TestSilencer(t *testing.T) {
 	require.True(t, s.Mutes(model.LabelSet{"foo": "bar"}), "expected alert silenced by activated second silence")
 }
 
-func TestValidateMatcher(t *testing.T) {
+func TestValidateClassicMatcher(t *testing.T) {
 	cases := []struct {
 		m   *pb.Matcher
 		err string
@@ -1154,6 +1154,103 @@ func TestValidateMatcher(t *testing.T) {
 				Type:    pb.Matcher_EQUAL,
 			},
 			err: "invalid label name",
+		}, {
+			m: &pb.Matcher{
+				Name:    "\xf0\x9f\x99\x82", // U+1F642
+				Pattern: "a",
+				Type:    pb.Matcher_EQUAL,
+			},
+			err: "invalid label name",
+		}, {
+			m: &pb.Matcher{
+				Name:    "a",
+				Pattern: "((",
+				Type:    pb.Matcher_REGEXP,
+			},
+			err: "invalid regular expression",
+		}, {
+			m: &pb.Matcher{
+				Name:    "a",
+				Pattern: "))",
+				Type:    pb.Matcher_NOT_REGEXP,
+			},
+			err: "invalid regular expression",
+		}, {
+			m: &pb.Matcher{
+				Name:    "a",
+				Pattern: "\xff",
+				Type:    pb.Matcher_EQUAL,
+			},
+			err: "invalid label value",
+		}, {
+			m: &pb.Matcher{
+				Name:    "a",
+				Pattern: "\xf0\x9f\x99\x82", // U+1F642
+				Type:    pb.Matcher_EQUAL,
+			},
+			err: "",
+		}, {
+			m: &pb.Matcher{
+				Name:    "a",
+				Pattern: "b",
+				Type:    333,
+			},
+			err: "unknown matcher type",
+		},
+	}
+
+	for _, c := range cases {
+		checkErr(t, c.err, validateClassicMatcher(c.m))
+	}
+}
+
+func TestValidateUTF8Matcher(t *testing.T) {
+	cases := []struct {
+		m   *pb.Matcher
+		err string
+	}{
+		{
+			m: &pb.Matcher{
+				Name:    "a",
+				Pattern: "b",
+				Type:    pb.Matcher_EQUAL,
+			},
+			err: "",
+		}, {
+			m: &pb.Matcher{
+				Name:    "a",
+				Pattern: "b",
+				Type:    pb.Matcher_NOT_EQUAL,
+			},
+			err: "",
+		}, {
+			m: &pb.Matcher{
+				Name:    "a",
+				Pattern: "b",
+				Type:    pb.Matcher_REGEXP,
+			},
+			err: "",
+		}, {
+			m: &pb.Matcher{
+				Name:    "a",
+				Pattern: "b",
+				Type:    pb.Matcher_NOT_REGEXP,
+			},
+			err: "",
+		}, {
+			m: &pb.Matcher{
+				Name:    "00",
+				Pattern: "a",
+				Type:    pb.Matcher_EQUAL,
+			},
+			err: "",
+		}, {
+			m: &pb.Matcher{
+				Name:    "\xf0\x9f\x99\x82", // U+1F642
+				Pattern: "a",
+				Type:    pb.Matcher_EQUAL,
+			},
+			err: "",
 		}, {
 			m: &pb.Matcher{
 				Name:    "a",
@@ -1175,6 +1272,13 @@ func TestValidateMatcher(t *testing.T) {
 				Type:    pb.Matcher_EQUAL,
 			},
 			err: "invalid label value",
+		}, {
+			m: &pb.Matcher{
+				Name:    "a",
+				Pattern: "\xf0\x9f\x99\x82", // U+1F642
+				Type:    pb.Matcher_EQUAL,
+			},
+			err: "",
 		}, {
 			m: &pb.Matcher{
 				Name:    "a",
@@ -1186,7 +1290,7 @@ func TestValidateMatcher(t *testing.T) {
 	}
 
 	for _, c := range cases {
-		checkErr(t, c.err, ValidateMatcher(c.m))
+		checkErr(t, c.err, validateUTF8Matcher(c.m))
 	}
 }