add fuzzing

.circleci/config.yml

@@ -1,10 +1,23 @@
 version: 2.1
-jobs:
-  build:
+
+executors:
+  # Whenever the Go version is updated here, .travis.yml and .promu.yml
+  # should also be updated.
+  golang:
     docker:
-      - image: "circleci/golang:1.12"
-        environment:
+    - image: circleci/golang:1.12
+      environment:
           GO111MODULE: "on"
+
+  fuzzit:
+    docker:
+      - image: fuzzitdev/golang:1.12.7-buster
+        environment:
+          GO111MODULE: "off"
+
+jobs:
+  test:
+    executor: golang
     working_directory: /go/src/github.com/marten-seemann/qpack
     steps:
       - checkout
@@ -29,3 +42,19 @@ jobs:
           command: |
             cat `find . -name "*.coverprofile"` > coverage.txt
             bash <(curl -s https://codecov.io/bash) -f coverage.txt
+  fuzzit:
+    executor: fuzzit
+    working_directory: /go/src/github.com/marten-seemann/qpack
+    steps:
+      - checkout
+      - setup_remote_docker
+      - run: go get ./...
+      - run: .circleci/fuzzit.sh
+
+workflows:
+  version: 2
+  qpack:
+    jobs:
+    - test
+    - fuzzit
+

.circleci/fuzzit.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+set -ex
+
+if [ "$CIRCLE_PULL_REQUEST" = "false" ]; then
+    export FUZZING_TYPE="fuzzing"
+    export BRANCH=${CIRCLE_BRANCH}
+else
+    export FUZZING_TYPE="local-regression"
+    export BRANCH="PR-${CIRCLE_PULL_REQUEST}"
+fi
+
+## Install fuzzit
+wget -q -O fuzzit https://github.com/fuzzitdev/fuzzit/releases/download/v2.4.44/fuzzit_Linux_x86_64
+chmod a+x fuzzit
+
+## Install go-fuzz
+go get -u github.com/dvyukov/go-fuzz/go-fuzz github.com/dvyukov/go-fuzz/go-fuzz-build
+
+cd fuzzing
+go-fuzz-build -libfuzzer -o fuzz-qpack.a .
+clang-9 -fsanitize=fuzzer fuzz-qpack.a -o fuzz-qpack
+cd ..
+
+# Create the jobs
+./fuzzit create job --type ${FUZZING_TYPE} --branch ${BRANCH} --revision=${CIRCLE_SHA1} quic-go/fuzz-header fuzzing/fuzz-qpack

.gitignore

@@ -0,0 +1,6 @@
+fuzzing/*.zip
+fuzzing/coverprofile
+fuzzing/crashers
+fuzzing/sonarprofile
+fuzzing/suppressions
+fuzzing/corpus/

fuzzing/fuzz.go

@@ -0,0 +1,76 @@
+// +build gofuzz
+
+package qpack
+
+import (
+	"bytes"
+	"fmt"
+	"reflect"
+
+	"github.com/marten-seemann/qpack"
+)
+
+func Fuzz(data []byte) int {
+	if len(data) < 1 {
+		return 0
+	}
+
+	chunkLen := int(data[0]) + 1
+	data = data[1:]
+
+	fields, err := qpack.NewDecoder(nil).DecodeFull(data)
+	if err != nil {
+		return 0
+	}
+	if len(fields) == 0 {
+		return 0
+	}
+
+	var writtenFields []qpack.HeaderField
+	decoder := qpack.NewDecoder(func(hf qpack.HeaderField) {
+		writtenFields = append(writtenFields, hf)
+	})
+	for len(data) > 0 {
+		var chunk []byte
+		if chunkLen <= len(data) {
+			chunk = data[:chunkLen]
+			data = data[chunkLen:]
+		} else {
+			chunk = data
+			data = nil
+		}
+		n, err := decoder.Write(chunk)
+		if err != nil {
+			return 0
+		}
+		if n != len(chunk) {
+			panic("len error")
+		}
+	}
+	if !reflect.DeepEqual(fields, writtenFields) {
+		fmt.Printf("%#v vs %#v", fields, writtenFields)
+		panic("Write() and DecodeFull() produced different results")
+	}
+
+	buf := &bytes.Buffer{}
+	encoder := qpack.NewEncoder(buf)
+	for _, hf := range fields {
+		if err := encoder.WriteField(hf); err != nil {
+			panic(err)
+		}
+	}
+	if err := encoder.Close(); err != nil {
+		panic(err)
+	}
+
+	encodedFields, err := qpack.NewDecoder(nil).DecodeFull(buf.Bytes())
+	if err != nil {
+		fmt.Printf("Fields: %#v\n", fields)
+		panic(err)
+	}
+	if !reflect.DeepEqual(fields, encodedFields) {
+		fmt.Printf("%#v vs %#v", fields, encodedFields)
+		panic("unequal")
+	}
+	return 0
+}