gwp-asan

Independent standalone gwp-asan, from llvm

This project is Linux only. It follows LLVM's upstream GWP-ASan support scope, which currently enables GWP-ASan on Linux.

What's this

GWP-ASan is a sampled allocator framework that assists in finding use-after-free and heap-buffer-overflow bugs in production environments.

This repo contains a standalone gwp-asan, you can easily use it with CMake.

Check the documents here: gwp-asan

Build

cmake -S . -B build -G Ninja
cmake --build build --parallel

Build the example:

cmake -S . -B build -G Ninja -DGWP_ASAN_BUILD_EXAMPLE=ON
cmake --build build --parallel

Run the upstream GWP-ASan unit tests:

cmake -S . -B build -G Ninja -DGWP_ASAN_BUILD_TESTING=ON
cmake --build build --parallel
ctest --test-dir build --output-on-failure

The tests require GoogleTest. Install libgtest-dev on Ubuntu or gtest-devel on Fedora/RHEL. If GoogleTest is not installed system-wide, pass -DGWP_ASAN_GTEST_SOURCE_DIR=/path/to/googletest.

Integration

TL;DR read the example

Integration by simply performing the following steps:

1. add hook to malloc/free

   void *operator new(std::size_t sz) {
       if (allocator.shouldSample()) {
           return allocator.allocate(sz, MinAlignment);
       }
       return malloc(sz);
   }
   
   void operator delete(void *ptr) {
       if (allocator.pointerIsMine(ptr)) {
           allocator.deallocate(ptr);
           return;
       }
       free(ptr);
   }

2. register SEGV handler and init the allocator

   gwp_asan::options::Options options;
   options.Enabled = true;
   options.MaxSimultaneousAllocations = 16;
   options.SampleRate = 3;
   options.Backtrace = gwp_asan::backtrace::getBacktraceFunction();
   allocator.init(options);
   gwp_asan::segv_handler::installSignalHandlers(
           &allocator, PrintfToBuffer,
           gwp_asan::backtrace::getPrintBacktraceFunction(),
           gwp_asan::backtrace::getSegvBacktraceFunction(),
           false
   );

Resolve output

./buggy-program | ./scripts/symbolize.sh