message: tests: Avoid fuzzer-specific nullptr dereference in libevent when handling PROXY requests
diff: #include <test/fuzz/FuzzedDataProvider.h>
  #include <test/fuzz/fuzz.h>
  #include <test/fuzz/util.h>
  +#include <util/strencodings.h>
  #include <event2/buffer.h>
  #include <event2/event.h>
  @@ -48,7 +49,14 @@ void test_one_input(const std::vector<uint8_t>& buffer)
  assert(evbuf != nullptr);
  const std::vector<uint8_t> http_buffer = ConsumeRandomLengthByteVector(fuzzed_data_provider, 4096);
  evbuffer_add(evbuf, http_buffer.data(), http_buffer.size());
  - if (evhttp_parse_firstline_(evreq, evbuf) != 1 || evhttp_parse_headers_(evreq, evbuf) != 1) {
  + // Avoid constructing requests that will be interpreted by libevent as PROXY requests to avoid triggering
  + // a nullptr dereference. The dereference (req->evcon->http_server) takes place in evhttp_parse_request_line
  + // and is a consequence of our hacky but necessary use of the internal function evhttp_parse_firstline_ in
  + // this fuzzing harness. The workaround is not aesthetically pleasing, but it successfully avoids the troublesome
  + // code path. " http:// HTTP/1.1\n" was a crashing input prior to this workaround.
  + const std::string http_buffer_str = ToLower({http_buffer.begin(), http_buffer.end()});
  + if (http_buffer_str.find(" http://") != std::string::npos || http_buffer_str.find(" https://") != std::string::npos ||
  + evhttp_parse_firstline_(evreq, evbuf) != 1 || evhttp_parse_headers_(evreq, evbuf) != 1) {
  evbuffer_free(evbuf);
  evhttp_request_free(evreq);
  return;
  