fuzz: introduce continuous fuzzing for Caddy (#2723)

* fuzz: lay down the foundation for continuous fuzzing

* improve the fuzzers and add some

* fuzz: add Fuzzit badge to README & enable fuzzers submission in CI

* v2-fuzz: do away with the submodule approach for fuzzers

* fuzz: enable fuzzit

1 files changed, 26 insertions, 0 deletions

diff --git a/replacer_fuzz.go b/replacer_fuzz.go
new file mode 100644
index 000000000..6d40cf73d
--- /dev/null
+++ b/replacer_fuzz.go
@@ -0,0 +1,26 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build gofuzz
+// +build gofuzz_libfuzzer
+
+package caddy
+
+func FuzzReplacer(data []byte) (score int) {
+	NewReplacer().ReplaceAll(string(data), "")
+	NewReplacer().ReplaceAll(NewReplacer().ReplaceAll(string(data), ""), "")
+	NewReplacer().ReplaceAll(NewReplacer().ReplaceAll(string(data), ""), NewReplacer().ReplaceAll(string(data), ""))
+	NewReplacer().ReplaceAll(string(data[:len(data)/2]), string(data[len(data)/2:]))
+	return 0
+}