[mtail] Fuzz the github.com/google/mtail project. (#3136)

* Add the github.com/google/mtail project.

* [mtail] Generate the seed corpus in the build script.

* [mtail] Specify the go-only fuzzing engine and sanitizers.

projects/mtail/Dockerfile

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+# Copyright 2019 Google Inc.
+#
+# 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.
+#
+################################################################################
+
+FROM gcr.io/oss-fuzz-base/base-builder
+MAINTAINER jaq@spacepants.org
+RUN mkdir -p github.com/google
+RUN git clone --depth 1 https://github.com/google/mtail github.com/google/mtail
+WORKDIR github.com/google/mtail
+COPY build.sh $SRC/

projects/mtail/build.sh

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+#!/bin/bash -eu
+# Copyright 2019 Google Inc.
+#
+# 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.
+#
+################################################################################
+
+# We've used git checkout, not go get to fetch the source so set up the GOPATH to find our source.
+export GOPATH=$GOPATH:/
+
+# go-fuzz-build doesn't like modules until https://github.com/dvyukov/go-fuzz/issues/195 is fixed
+# fetch and vendor all the dependencies so go-fuzz-build can find them
+make GO111MODULE=off --debug install_deps
+go mod vendor
+
+make GO111MODULE=off --debug $OUT/vm-fuzzer.dict $OUT/vm-fuzzer_seed_corpus.zip $OUT/vm-fuzzer

projects/mtail/project.yaml

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+homepage: https://github.com/google/mtail
+primary_contact: jaq@spacepants.org
+fuzzing_engines:
+  - libfuzzer
+sanitizers:
+  - address