Integrate libsass and add a fuzz target. (#2039)

projects/libsass/Dockerfile

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+# Copyright 2018 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
+RUN apt-get update && apt-get install -y make autoconf automake libtool
+RUN git clone --depth 1 https://github.com/sass/libsass.git libsass
+WORKDIR $SRC
+COPY build.sh $SRC/
+COPY data_context_fuzzer.cc $SRC/

projects/libsass/build.sh

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+#!/bin/bash -eu
+# Copyright 2018 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.
+#
+################################################################################
+
+pushd libsass
+export BUILD='static'
+make -j$(nproc)
+popd
+
+INSTALL_DIR="$SRC/libsass"
+
+$CXX $CXXFLAGS -I${INSTALL_DIR}/include -lFuzzingEngine data_context_fuzzer.cc \
+  -o $OUT/data_context_fuzzer ${INSTALL_DIR}/lib/libsass.a

projects/libsass/data_context_fuzzer.cc

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+#include "sass.h"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  char* sass_data = (char*) malloc(sizeof(char) * size + 1);
+  if (sass_data == NULL) return 0;
+
+  memcpy(sass_data, data, size);
+  sass_data[size] = '\0';
+
+  struct Sass_Data_Context* ctx = sass_make_data_context(sass_data);
+  if (ctx == NULL) {
+    free(sass_data);
+    return 0;
+  }
+
+  struct Sass_Options* options = sass_make_options();
+  if (options == NULL) {
+    sass_delete_data_context(ctx);
+    return 0;
+  }
+
+  sass_option_set_output_style(options, SASS_STYLE_NESTED);
+  sass_option_set_precision(options, 5);
+
+  sass_data_context_set_options(ctx, options);
+  sass_compile_data_context(ctx);
+
+  sass_delete_data_context(ctx);
+  sass_delete_options(options);
+
+  return 0;
+}

projects/libsass/project.yaml

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+homepage: "http://libsass.org/"
+primary_contact: "kusano@google.com"
+
+experimental: true
+
+sanitizers:
+  - address
+  - memory
+  - undefined
+
+labels:
+  data_context_fuzze:
+    - sundew