llamacpp: add harness (google#12418)

Signed-off-by: David Korczynski <david@adalogics.com>

projects/llamacpp/build.sh

@@ -47,6 +47,7 @@ FLAGS="-std=c++11 -Iggml/include -Iggml/src -Iinclude -Isrc -Icommon -I./ -DNDEB
 cp fuzzers/*.dict $OUT/
 
 $CXX $LIB_FUZZING_ENGINE $CXXFLAGS ${FLAGS} ${OBJ_FILES} fuzzers/fuzz_json_to_grammar.cpp -o $OUT/fuzz_json_to_grammar
+$CXX $LIB_FUZZING_ENGINE $CXXFLAGS ${FLAGS} ${OBJ_FILES} fuzzers/fuzz_apply_template.cpp -o $OUT/fuzz_apply_template
 $CXX $LIB_FUZZING_ENGINE $CXXFLAGS ${FLAGS} ${OBJ_FILES} fuzzers/fuzz_grammar.cpp -o $OUT/fuzz_grammar
 
 # Create a corpus for load_model_fuzzer

projects/llamacpp/fuzzers/fuzz_apply_template.cpp

@@ -0,0 +1,39 @@
+/* Copyright 2024 Google LLC
+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.
+*/
+
+#include "llama.h"
+#include <fuzzer/FuzzedDataProvider.h>
+
+char buf[4096];
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  FuzzedDataProvider fuzzed_data(data, size);
+
+  std::string p1 = fuzzed_data.ConsumeRandomLengthString();
+  std::string p2 = fuzzed_data.ConsumeRandomLengthString();
+  std::string p3 = fuzzed_data.ConsumeRandomLengthString();
+  std::string p4 = fuzzed_data.ConsumeRandomLengthString();
+  std::string p5 = fuzzed_data.ConsumeRandomLengthString();
+  std::string p6 = fuzzed_data.ConsumeRandomLengthString();
+  std::string p7 = fuzzed_data.ConsumeRandomLengthString();
+
+  llama_chat_message conversation[] = {
+      {"system", p2.c_str()},    {"user", p3.c_str()},
+      {"assistant", p4.c_str()}, {"user", p5.c_str()},
+      {"assistant", p6.c_str()}, {"user", p7.c_str()},
+  };
+  size_t message_count = 6;
+
+  llama_chat_apply_template(nullptr, p1.c_str(), conversation, message_count,
+                            true, buf, 4096);
+  return 0;
+}