fix: quote empty string key in ast (bytedance#427)

* fix: quote empty string key in ast

* test: enhance ast fuzz

* fix: unquote as default encoding json

Author: liuq19

ast/api_amd64.go

@@ -37,6 +37,7 @@ func quote(buf *[]byte, val string) {
     *buf = append(*buf, '"')
     if len(val) == 0 {
         *buf = append(*buf, '"')
+        return
     }
 
     sp := rt.IndexChar(val, 0)

ast/encode_test.go

@@ -88,10 +88,12 @@ func TestEncodeValue(t *testing.T) {
         {NewString(`\"\"`), `"\\\"\\\""`, false},
         {NewString(_TwitterJson), string(quote), false},
         {NewArray([]Node{}), "[]", false},
+        {NewArray([]Node{NewString(""), NewNull()}), `["",null]`, false},
         {NewArray([]Node{NewBool(true), NewString("true"), NewString("\t")}), `[true,"true","\t"]`, false},
         {NewObject([]Pair{Pair{"a", NewNull()}, Pair{"b", NewNumber("0")}}), `{"a":null,"b":0}`, false},
         {NewObject([]Pair{Pair{"\ta", NewString("\t")}, Pair{"\bb", NewString("\b")}, Pair{"\nb", NewString("\n")}, Pair{"\ra", NewString("\r")}}),`{"\ta":"\t","\u0008b":"\u0008","\nb":"\n","\ra":"\r"}`, false},
         {NewObject([]Pair{}), `{}`, false},
+        {NewObject([]Pair{Pair{Key: "", Value: NewNull()}}), `{"":null}`, false},
         {NewBytes([]byte("hello, world")), `"aGVsbG8sIHdvcmxk"`, false},
         {NewAny(obj), string(buf), false},
         {NewRaw(`[{ }]`), "[{}]", false},

fuzz/fuzz_test.go

@@ -46,6 +46,8 @@ func FuzzMain(f *testing.F) {
 // Used for debug falied fuzz corpus
 func TestCorpus(t *testing.T) {
     fuzzMain(t, []byte("[1\x00"))
+    fuzzMain(t, []byte("\"\\uDE1D\\uDE1D\\uDEDD\\uDE1D\\uDE1D\\uDE1D\\uDE1D\\uDEDD\\uDE1D\""))
+    // fuzzMain(t, []byte(`{"":null}`))
 }
 
 var target = sonic.ConfigStd
@@ -59,7 +61,7 @@ func fuzzMain(t *testing.T, data []byte) {
     if !json.Valid(data) {
         return
     }
-    for _, typ := range []func() interface{}{
+    for i, typ := range []func() interface{}{
         func() interface{} { return new(interface{}) },
         func() interface{} { return new(map[string]interface{}) },
         func() interface{} { return new([]interface{}) },
@@ -70,9 +72,10 @@ func fuzzMain(t *testing.T, data []byte) {
         // func() interface{} { return new(json.Number) },
         // func() interface{} { return new(S) },
     } {
-        sv, jv := typ(), typ()
-        serr := target.Unmarshal([]byte(data), sv)
-        jerr := json.Unmarshal([]byte(data), jv)
+        var sv = typ()
+        var jv = typ()
+        serr := target.Unmarshal(data, sv)
+        jerr := json.Unmarshal(data, jv)
         require.Equal(t, serr != nil, jerr != nil, 
                 dump(data, jv, jerr, sv, serr))
         if jerr != nil {
@@ -87,7 +90,7 @@ func fuzzMain(t *testing.T, data []byte) {
         require.NoError(t, jerr, dump(v, jout, jerr, sout, serr))
 
         {
-            sv, jv := typ(), typ()
+            sv, jv = typ(), typ()
             serr := target.Unmarshal(sout, sv)
             jerr := json.Unmarshal(jout, jv)
             require.Equalf(t, serr != nil, jerr != nil, dump(data, jv, jerr, sv, serr))
@@ -97,6 +100,20 @@ func fuzzMain(t *testing.T, data []byte) {
             require.Equal(t, sv, jv, dump(data, jv, jerr, sv, serr))
         }
 
+        // fuzz ast MarshalJSON API
+        if i == 0 {
+            root, aerr := sonic.Get(data)
+            require.Equal(t, aerr, nil)
+            aerr = root.LoadAll()
+            require.Equal(t, aerr, nil, dump(data, jv, jerr, root, aerr))
+            aout, aerr := root.MarshalJSON()
+            require.Equal(t, aerr, nil)
+            sv = typ()
+            serr := json.Unmarshal(aout, sv)
+            require.Equal(t, serr, nil)
+            require.Equal(t, sv, jv, dump(data, jv, jerr, sv, serr))
+        }
+
         if m, ok := sv.(*map[string]interface{}); ok {
             fuzzDynamicStruct(t, jout, *m)
             fuzzASTGetFromObject(t, jout, *m)

unquote/unquote.go

@@ -18,6 +18,7 @@ package unquote
 
 import (
     `unsafe`
+    `runtime`
 
     `github.com/bytedance/sonic/internal/native`
     `github.com/bytedance/sonic/internal/native/types`
@@ -43,7 +44,8 @@ func intoBytesUnsafe(s string, m *[]byte) types.ParsingError {
     pos := -1
     slv := (*rt.GoSlice)(unsafe.Pointer(m))
     str := (*rt.GoString)(unsafe.Pointer(&s))
-    ret := native.Unquote(str.Ptr, str.Len, slv.Ptr, &pos, 0)
+    /* unquote as the default configuration, replace invalid unicode with \ufffd */
+    ret := native.Unquote(str.Ptr, str.Len, slv.Ptr, &pos, types.F_UNICODE_REPLACE)
 
     /* check for errors */
     if ret < 0 {
@@ -52,5 +54,6 @@ func intoBytesUnsafe(s string, m *[]byte) types.ParsingError {
 
     /* update the length */
     slv.Len = ret
+    runtime.KeepAlive(s)
     return 0
 }