1 files changed, 86 insertions, 0 deletions
diff --git a/internal/fuzz/wirefuzz/fuzz.go b/internal/fuzz/wirefuzz/fuzz.go
new file mode 100644
index 00000000..fd27cca6
--- /dev/null
+++ b/internal/fuzz/wirefuzz/fuzz.go
@@ -0,0 +1,86 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package wirefuzz includes a fuzzer for the wire marshaler and unmarshaler.
+package wirefuzz
+
+import (
+	"fmt"
+
+	"google.golang.org/protobuf/internal/impl"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoregistry"
+	piface "google.golang.org/protobuf/runtime/protoiface"
+
+	fuzzpb "google.golang.org/protobuf/internal/testprotos/fuzz"
+)
+
+// Fuzz is a fuzzer for proto.Marshal and proto.Unmarshal.
+func Fuzz(data []byte) (score int) {
+	// Unmarshal and Validate should agree about the validity of the message.
+	m1 := &fuzzpb.Fuzz{}
+	mt := m1.ProtoReflect().Type()
+	_, valid := impl.Validate(mt, piface.UnmarshalInput{Buf: data})
+	if err := (proto.UnmarshalOptions{AllowPartial: true}).Unmarshal(data, m1); err != nil {
+		switch valid {
+		case impl.ValidationUnknown:
+		case impl.ValidationInvalid:
+		default:
+			panic("unmarshal error with validation status: " + valid.String())
+		}
+		return 0
+	}
+	switch valid {
+	case impl.ValidationUnknown:
+	case impl.ValidationValid:
+	default:
+		panic("unmarshal ok with validation status: " + valid.String())
+	}
+
+	// Unmarshal, Validate, and CheckInitialized should agree about initialization.
+	checkInit := proto.CheckInitialized(m1) == nil
+	methods := m1.ProtoReflect().ProtoMethods()
+	in := piface.UnmarshalInput{Message: mt.New(), Resolver: protoregistry.GlobalTypes, Depth: 10000}
+	if checkInit {
+		// If the message initialized, the both Unmarshal and Validate should
+		// report it as such. False negatives are tolerated, but have a
+		// significant impact on performance. In general, they should always
+		// properly determine initialization for any normalized message,
+		// we produce by re-marshaling the message.
+		in.Buf, _ = proto.Marshal(m1)
+		if out, _ := methods.Unmarshal(in); out.Flags&piface.UnmarshalInitialized == 0 {
+			panic("unmarshal reports initialized message as partial")
+		}
+		if out, _ := impl.Validate(mt, in); out.Flags&piface.UnmarshalInitialized == 0 {
+			panic("validate reports initialized message as partial")
+		}
+	} else {
+		// If the message is partial, then neither Unmarshal nor Validate
+		// should ever report it as such. False positives are unacceptable.
+		in.Buf = data
+		if out, _ := methods.Unmarshal(in); out.Flags&piface.UnmarshalInitialized != 0 {
+			panic("unmarshal reports partial message as initialized")
+		}
+		if out, _ := impl.Validate(mt, in); out.Flags&piface.UnmarshalInitialized != 0 {
+			panic("validate reports partial message as initialized")
+		}
+	}
+
+	// Round-trip Marshal and Unmarshal should produce the same messages.
+	data1, err := proto.MarshalOptions{AllowPartial: !checkInit}.Marshal(m1)
+	if err != nil {
+		panic(err)
+	}
+	if proto.Size(m1) != len(data1) {
+		panic(fmt.Errorf("size does not match output: %d != %d", proto.Size(m1), len(data1)))
+	}
+	m2 := &fuzzpb.Fuzz{}
+	if err := (proto.UnmarshalOptions{AllowPartial: !checkInit}).Unmarshal(data1, m2); err != nil {
+		panic(err)
+	}
+	if !proto.Equal(m1, m2) {
+		panic("not equal")
+	}
+	return 1
+}