make: add fuzz-build and fuzz commands

Makefile

@@ -8,6 +8,8 @@ LINT_PKG := github.com/golangci/golangci-lint/cmd/golangci-lint
 GOACC_PKG := github.com/ory/go-acc
 FALAFEL_PKG := github.com/lightninglabs/falafel
 GOIMPORTS_PKG := golang.org/x/tools/cmd/goimports
+GOFUZZ_BUILD_PKG := github.com/dvyukov/go-fuzz/go-fuzz-build
+GOFUZZ_PKG := github.com/dvyukov/go-fuzz/go-fuzz
 
 GO_BIN := ${GOPATH}/bin
 BTCD_BIN := $(GO_BIN)/btcd
@@ -15,6 +17,8 @@ GOMOBILE_BIN := GO111MODULE=off $(GO_BIN)/gomobile
 GOVERALLS_BIN := $(GO_BIN)/goveralls
 LINT_BIN := $(GO_BIN)/golangci-lint
 GOACC_BIN := $(GO_BIN)/go-acc
+GOFUZZ_BUILD_BIN := $(GO_BIN)/go-fuzz-build
+GOFUZZ_BIN := $(GO_BIN)/go-fuzz
 
 BTCD_DIR :=${GOPATH}/src/$(BTCD_PKG)
 MOBILE_BUILD_DIR :=${GOPATH}/src/$(MOBILE_PKG)/build
@@ -35,6 +39,7 @@ BTCD_COMMIT := $(shell cat go.mod | \
 LINT_COMMIT := v1.18.0
 GOACC_COMMIT := ddc355013f90fea78d83d3a6c71f1d37ac07ecd5
 FALAFEL_COMMIT := v0.7.1
+GOFUZZ_COMMIT := 21309f307f61
 
 DEPGET := cd /tmp && GO111MODULE=on go get -v
 GOBUILD := GO111MODULE=on go build -v
@@ -51,6 +56,7 @@ XARGS := xargs -L 1
 
 include make/testing_flags.mk
 include make/release_flags.mk
+include make/fuzz_flags.mk
 
 DEV_TAGS := $(if ${tags},$(DEV_TAGS) ${tags},$(DEV_TAGS))
 
@@ -116,6 +122,14 @@ goimports:
 	@$(call print, "Installing goimports.")
 	$(DEPGET) $(GOIMPORTS_PKG)
 
+$(GOFUZZ_BIN):
+	@$(call print, "Fetching go-fuzz")
+	$(DEPGET) $(GOFUZZ_PKG)@$(GOFUZZ_COMMIT)
+
+$(GOFUZZ_BUILD_BIN):
+	@$(call print, "Fetching go-fuzz-build")
+	$(DEPGET) $(GOFUZZ_BUILD_PKG)@$(GOFUZZ_COMMIT)
+
 # ============
 # INSTALLATION
 # ============
@@ -197,6 +211,17 @@ flake-unit:
 	@$(call print, "Flake hunting unit tests.")
 	while [ $$? -eq 0 ]; do GOTRACEBACK=all $(UNIT) -count=1; done
 
+# =============
+# FUZZING
+# =============
+fuzz-build: $(GOFUZZ_BUILD_BIN)
+	@$(call print, "Creating fuzz harnesses for packages '$(FUZZPKG)'.")
+	scripts/fuzz.sh build "$(FUZZPKG)"
+
+fuzz-run: $(GOFUZZ_BIN)
+	@$(call print, "Fuzzing packages '$(FUZZPKG)'.")
+	scripts/fuzz.sh run "$(FUZZPKG)" "$(FUZZ_TEST_RUN_TIME)" "$(FUZZ_TEST_TIMEOUT)" "$(FUZZ_NUM_PROCESSES)" "$(FUZZ_BASE_WORKDIR)"
+
 # =========
 # UTILITIES
 # =========

make/fuzz_flags.mk

@@ -0,0 +1,34 @@
+FUZZPKG = brontide lnwire wtwire
+FUZZ_TEST_RUN_TIME = 30
+FUZZ_TEST_TIMEOUT = 20
+FUZZ_NUM_PROCESSES = 4
+FUZZ_BASE_WORKDIR = $(shell pwd)/fuzz
+
+# If specific package is being fuzzed, construct the full name of the
+# subpackage.
+ifneq ($(pkg),)
+FUZZPKG := $(pkg)
+endif
+
+# The default run time per fuzz test is pretty low and normally will be
+# overwritten by a user depending on the time they have available.
+ifneq ($(run_time),)
+FUZZ_TEST_RUN_TIME := $(run_time)
+endif
+
+# If the timeout needs to be increased, overwrite the default value.
+ifneq ($(timeout),)
+FUZZ_TEST_TIMEOUT := $(timeout)
+endif
+
+# Overwrites the number of parallel processes. Should be set to the number of
+# processor cores in a system.
+ifneq ($(processes),)
+FUZZ_NUM_PROCESSES := $(processes)
+endif
+
+# Overwrite the base work directory for the fuzz run. Can be used to supply any
+# previously generated corpus.
+ifneq ($(base_workdir),)
+FUZZ_BASE_WORKDIR := $(base_workdir)
+endif

scripts/fuzz.sh

@@ -0,0 +1,90 @@
+#!/bin/bash
+
+set -e
+
+function build_fuzz() {
+  PACKAGES=$1
+
+  for pkg in $PACKAGES; do
+    pushd fuzz/$pkg
+
+    for file in *.go; do
+      if [[ "$file" == "fuzz_utils.go" ]]; then
+        continue
+      fi
+
+      NAME=$(echo $file | sed 's/\.go$//1')
+      echo "Building zip file for $pkg/$NAME"
+      go-fuzz-build -func "Fuzz_$NAME" -o "$pkg-$NAME-fuzz.zip" "github.com/lightningnetwork/lnd/fuzz/$pkg"
+    done
+
+    popd
+  done
+}
+
+# timeout is a cross platform alternative to the GNU timeout command that
+# unfortunately isn't available on macOS by default.
+timeout() {
+    time=$1
+    $2 &
+    pid=$!
+    sleep $time
+    kill -s SIGINT $pid    
+}
+
+function run_fuzz() {
+  PACKAGES=$1
+  RUN_TIME=$2
+  TIMEOUT=$3
+  PROCS=$4
+  BASE_WORKDIR=$5
+
+  for pkg in $PACKAGES; do
+    pushd fuzz/$pkg
+
+    for file in *.go; do
+      if [[ "$file" == "fuzz_utils.go" ]]; then
+        continue
+      fi
+
+      NAME=$(echo $file | sed 's/\.go$//1')
+      WORKDIR=$BASE_WORKDIR/$pkg/$NAME
+      mkdir -p $WORKDIR
+      echo "Running fuzzer $pkg-$NAME-fuzz.zip with $PROCS processors for $RUN_TIME seconds"
+      COMMAND="go-fuzz -bin=$pkg-$NAME-fuzz.zip -workdir=$WORKDIR -procs=$PROCS -timeout=$TIMEOUT"
+      echo "$COMMAND"
+      timeout "$RUN_TIME" "$COMMAND"
+    done
+
+    popd
+  done
+}
+
+# usage prints the usage of the whole script.
+function usage() {
+  echo "Usage: "
+  echo "fuzz.sh build <packages>"
+  echo "fuzz.sh run <packages> <run_time> <timeout>"
+}
+
+# Extract the sub command and remove it from the list of parameters by shifting
+# them to the left.
+SUBCOMMAND=$1
+shift
+
+# Call the function corresponding to the specified sub command or print the
+# usage if the sub command was not found.
+case $SUBCOMMAND in
+build)
+  echo "Building fuzz packages"
+  build_fuzz "$@"
+  ;;
+run)
+  echo "Running fuzzer"
+  run_fuzz "$@"
+  ;;
+*)
+  usage
+  exit 1
+  ;;
+esac