ProtoFuzz

ProtoFuzz is a protoc plugin to generate implementations of github.com/google/gofuzz.Interface for generated Protobuf types.

Usage

Generating Code

The ProtoFuzz protoc plugin may be installed by running go install github.com/hxtk/protofuzz/protoc-gen-go-fuzz@latest. This process requires that protoc be installed on the host machine. Users may invoke protoc-gen-go-fuzz through protoc by specifying the argument --go-fuzz_out. Additional options may be specified via --go-fuzz_opt, e.g., --go-fuzz_opt=paths=source_relative.

Alternatively, a docker image is provided at docker.io/hxtk/protofuzz. This image is (mostly) compliant with https://google.aip.dev/client-libraries/4290. It does not currently support the PROTO files found in github.com/googleapis/googleapis as default includes. To use the docker interface, mount the input and output directories into the container at /in and /out, as shown below.

docker run --rm --user $UID \
    --mount type=bind,source=$PWD/path/to/api/v1,destination=/in/path/to/api/v1,readonly \
    --mount type=bind,source=$PWD/path/to/dest,destination=/out/ \
    docker.io/hxtk/protofuzz:latest

For example, to generate the proto files for this repository's test directory, a user with a shell in the repository root might run the following command:

docker run --rm --user $UID \
    --mount type=bind,source=$PWD/tests,destination=/in/github.com/hxtk/protofuzz/tests,readonly \
    --mount type=bind,source=$PWD/tests,destination=/out/github.com/hxtk/protofuzz/tests \
    docker.io/hxtk/protofuzz:latest

Writing Fuzzers

package foo_test

import (
	"context"
	"testing"

	fuzz "github.com/google/gofuzz"

	pb "example.com/your/proto/v1"
)

func FuzzSomeMethod(f *testing.F) {
	f.Fuzz(func(t *testing.T, data []byte) {
		fuzzer := fuzz.FromGoFuzz(data).WithNilChance(0.01)

		var request pb.SomeMethodRequest
		fuzzer.Fuzz(&request)

		// request has now been initialized to a random value
		// suitable for use in a fuzz test.
	}
}