protobuf-go/internal/fuzz/wirefuzz/fuzz.go
Lasse Folger 3992ea83a2 all: implement depth limit for unmarshaling
+ This change introduce a default and configurable depth limit for
  proto.Unmarshal. If a message is nested deeper than the limit,
  unmarshaling will fail. There are two ways to nest messages. Either by
  having fields which are message types itself or by using groups.
+ The default limit is 10,000 for now. This might change in the future
  to align it with other language implementation (C++ and Java use 100
  as limit).
+ If pure groups (groups that don't contain message fields) are nested
  deeper than the default limit the unmarshaling fails with:
  proto: cannot parse invalid wire-format data
+ Note: the configured limit does not apply to pure groups.
+ This change is introduced to improve security and robustness. Because
  unmarshaling is implemented using recursion it can lead to stack overflows
  for certain inputs. The introduced limit protects against this.
+ A secondary motivation for this limit is the alignment with other
  languages. Protocol buffers are a language interoperability mechanism
  and thus either all implementations should accept the input or all
  implementation should reject the input.

Change-Id: I14bdb44d06e4bd1aa90d6336c2cf6446003b2037
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/385854
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Trust: Damien Neil <dneil@google.com>
Reviewed-by: Nicolas Hillegeer <aktau@google.com>
Reviewed-by: Chressie Himpel <chressie@google.com>
2022-02-17 17:07:31 +00:00

87 lines
3.1 KiB
Go

// 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
}