protoc-gen-messageintegrity

Implicit Message Integrity

Code for the thesis "Implicit Message Integrity in Heterogeneous Systems".

This library provides a plugin to protocol buffer go complier protoc-gen-go to allow automatic generation of code for signing and verification of Protocol Buffer messages.

Installing

go get -u github.com/einride/protoc-gen-messageintegrity

Running

protoc --proto_path=src --go_out=gen --messageintegrity_out=gen --go_opt=paths=source_relative src/example/v1/steering_command_example.proto

Example

By adding the custom option integrity.v1.signature to a field of a message the plugin will know to add signing and verification methods to the generated type:

message SteeringCommand {
    float steering_angle = 1;
    bytes signature = 2 [(integrity.v1.signature) = {
      behaviour: SIGNATURE_BEHAVIOUR_REQUIRED,
        }];
}

This will create a file proto_file_name.message_integrity.go with Sign() and Verify() receiver methods beside the proto_file_name.pb.go:

...
func (x *SteeringCommand) Sign() error {
	keyID := os.Getenv(ImplicitMessageIntegrityKeyID)
	return verificationRsaOption.SignPKCS1v15(x, verificationRsaOption.KeyID(keyID))
}

func (x *SteeringCommand) Verify() (bool, error) {
	keyID := os.Getenv(ImplicitMessageIntegrityKeyID)
	return verificationRsaOption.ValidatePKCS1v15(x, verificationRsaOption.KeyID(keyID))
}
...

Then to sign a message before it is marhsalled a developer writes:

msg.Sign()
proto.Marshal(msg)

To verify a message after it is unmarshaled the following is required:

proto.Unmarshal(bytes, &msg)
if ok, err := msg.Verify(); !ok || err != nil {
	// Signature does not match
}

Message Integrity Linter

Additionally a custom linter to ensure correct use of the message integrity plugin was created. It checks that messages are signed before they are marshaled and that they are verified before they are unmarshaled. It only checks messages which have the custom option enabled.

Building

go build -o bin/integritylint cmd/integritylint/main.go

Running

./bin/integritylint go_file.go