test(parsers.json): add fuzz test (#12368)

internal/fuzz/json.go

@@ -0,0 +1,42 @@
+package fuzz
+
+// https://github.com/google/AFL/blob/master/dictionaries/json.dict
+var JSONDictionary = []string{
+	"0",
+	",0",
+	":0",
+	"0:",
+	"-1.2e+3",
+	"true",
+	"false",
+	"null",
+	"\"\"",
+	",\"\"",
+	":\"\"",
+	"\"\":",
+	"{}",
+	",{}",
+	":{}",
+	"{\"\":0}",
+	"{{}}",
+	"[]",
+	",[]",
+	":[]",
+	"[0]",
+	"[[]]",
+	"''",
+	"\\",
+	"\\b",
+	"\\f",
+	"\\n",
+	"\\r",
+	"\\t",
+	"\\u0000",
+	"\\x00",
+	"\\0",
+	"\\uD800\\uDC00",
+	"\\uDBFF\\uDFFF",
+	"\"\":0",
+	"//",
+	"/**/",
+}

plugins/parsers/json/parser_test.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/internal/fuzz"
 	"github.com/influxdata/telegraf/testutil"
 	"github.com/stretchr/testify/require"
 )
@@ -1356,3 +1357,23 @@ func TestParseArrayWithWildcardTagKeys(t *testing.T) {
 		})
 	}
 }
+
+func FuzzParserJSON(f *testing.F) {
+	for _, value := range fuzz.JSONDictionary {
+		f.Add([]byte(value))
+	}
+
+	f.Add([]byte(validJSON))
+	f.Add([]byte(validJSONArray))
+	f.Add([]byte(validJSONArrayMultiple))
+	f.Add([]byte(validJSONArrayTags))
+	f.Add([]byte(validJSONNewline))
+	f.Add([]byte(validJSONTags))
+
+	parser := &Parser{MetricName: "testing"}
+	require.NoError(f, parser.Init())
+
+	f.Fuzz(func(t *testing.T, input []byte) {
+		_, _ = parser.Parse(input)
+	})
+}