Revert back to using custom HTTP parser instead of Boost.Beast (#6407)

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Unreleased
   - Changes from 5.27.0
     - Misc:
+      - FIXED: Revert back to using custom HTTP parser instead of Boost.Beast. [#6407](https://github.com/Project-OSRM/osrm-backend/pull/6407)
       - FIXED: Fix bug with large HTTP requests leading to Bad Request in osrm-routed. [#6403](https://github.com/Project-OSRM/osrm-backend/pull/6403)
     - Routing:
       - CHANGED: Add support for surface=metal,grass_paver,woodchips in bicyle profile. [#6395](https://github.com/Project-OSRM/osrm-backend/pull/6395)

features/step_definitions/requests.js

@@ -55,4 +55,4 @@ module.exports = function () {
         assert.equal(this.processError.process, binary);
         assert.equal(parseInt(this.processError.code), parseInt(code));
     });
-};
+};

fuzz/CMakeLists.txt

@@ -38,7 +38,8 @@ if (ENABLE_FUZZING)
 	  "table_parameters"
 	  "tile_parameters"
 	  "trip_parameters"
-	  "url_parser")
+	  "url_parser"
+	  "request_parser")
 
   foreach (target ${ServerTargets})
 	  add_fuzz_target(${target})

fuzz/request_parser.cc

@@ -0,0 +1,28 @@
+#include "server/request_parser.hpp"
+#include "server/http/request.hpp"
+
+#include "util.hpp"
+
+#include <iterator>
+#include <string>
+
+using osrm::server::RequestParser;
+using osrm::server::http::request;
+
+extern "C" int LLVMFuzzerTestOneInput(const unsigned char *data, unsigned long size)
+{
+    std::string in(reinterpret_cast<const char *>(data), size);
+
+    auto first = begin(in);
+    auto last = end(in);
+
+    RequestParser parser;
+    request req;
+
+    // &(*it) is needed to go from iterator to underlying item to pointer to underlying item
+    parser.parse(req, &(*first), &(*last));
+
+    escape(&req);
+
+    return 0;
+}

include/server/connection.hpp

@@ -4,15 +4,14 @@
 #include "server/http/compression_type.hpp"
 #include "server/http/reply.hpp"
 #include "server/http/request.hpp"
+#include "server/request_parser.hpp"
+
 #include <boost/array.hpp>
 #include <boost/asio.hpp>
-#include <boost/beast/core.hpp>
-#include <boost/beast/http.hpp>
 #include <boost/config.hpp>
 #include <boost/version.hpp>
 
 #include <memory>
-#include <optional>
 #include <vector>
 
 // workaround for incomplete std::shared_ptr compatibility in old boost versions
@@ -48,7 +47,6 @@ class Connection : public std::enable_shared_from_this<Connection>
     void start();
 
   private:
-    using RequestParser = boost::beast::http::request_parser<boost::beast::http::string_body>;
     void handle_read(const boost::system::error_code &e, std::size_t bytes_transferred);
 
     /// Handle completion of a write operation.
@@ -62,14 +60,12 @@ class Connection : public std::enable_shared_from_this<Connection>
     std::vector<char> compress_buffers(const std::vector<char> &uncompressed_data,
                                        const http::compression_type compression_type);
 
-    void fill_request(const RequestParser::value_type &httpMessage, http::request &request);
-
     boost::asio::strand<boost::asio::io_context::executor_type> strand;
     boost::asio::ip::tcp::socket TCP_socket;
     boost::asio::deadline_timer timer;
     RequestHandler &request_handler;
-    std::optional<RequestParser> http_request_parser;
-    std::vector<char> incoming_data_buffer;
+    RequestParser request_parser;
+    boost::array<char, 8192> incoming_data_buffer;
     http::request current_request;
     http::reply current_reply;
     std::vector<char> compressed_output;

include/server/request_parser.hpp

@@ -0,0 +1,75 @@
+#ifndef REQUEST_PARSER_HPP
+#define REQUEST_PARSER_HPP
+
+#include "server/http/compression_type.hpp"
+#include "server/http/header.hpp"
+
+#include <tuple>
+
+namespace osrm
+{
+namespace server
+{
+
+namespace http
+{
+struct request;
+}
+
+class RequestParser
+{
+  public:
+    RequestParser();
+
+    enum class RequestStatus : char
+    {
+        valid,
+        invalid,
+        indeterminate
+    };
+
+    std::tuple<RequestStatus, http::compression_type>
+    parse(http::request &current_request, char *begin, char *end);
+
+  private:
+    RequestStatus consume(http::request &current_request, const char input);
+
+    bool is_char(const int character) const;
+
+    bool is_CTL(const int character) const;
+
+    bool is_special(const int character) const;
+
+    bool is_digit(const int character) const;
+
+    enum class internal_state : unsigned char
+    {
+        method_start,
+        method,
+        uri_start,
+        uri,
+        http_version_h,
+        http_version_t_1,
+        http_version_t_2,
+        http_version_p,
+        http_version_slash,
+        http_version_major_start,
+        http_version_major,
+        http_version_minor_start,
+        http_version_minor,
+        expecting_newline_1,
+        header_line_start,
+        header_lws,
+        header_name,
+        header_value,
+        expecting_newline_2,
+        expecting_newline_3
+    } state;
+
+    http::header current_header;
+    http::compression_type selected_compression;
+};
+} // namespace server
+} // namespace osrm
+
+#endif // REQUEST_PARSER_HPP

src/server/connection.cpp

@@ -1,51 +1,27 @@
 #include "server/connection.hpp"
 #include "server/request_handler.hpp"
+#include "server/request_parser.hpp"
 
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/bind.hpp>
 #include <boost/iostreams/filter/gzip.hpp>
 #include <boost/iostreams/filtering_stream.hpp>
+
 #include <vector>
 
 namespace osrm
 {
 namespace server
 {
 
-namespace
-{
-const size_t CHUNK_SIZE = 8192;
-
-} // namespace
 Connection::Connection(boost::asio::io_context &io_context, RequestHandler &handler)
     : strand(boost::asio::make_strand(io_context)), TCP_socket(strand), timer(strand),
-      request_handler(handler), http_request_parser(std::make_optional<RequestParser>())
+      request_handler(handler)
 {
-    http_request_parser->header_limit(std::numeric_limits<std::uint32_t>::max());
 }
 
 boost::asio::ip::tcp::socket &Connection::socket() { return TCP_socket; }
 
-namespace
-{
-
-http::compression_type select_compression(const boost::beast::http::fields &fields)
-{
-    const auto header_value = fields[boost::beast::http::field::accept_encoding];
-    /* giving gzip precedence over deflate */
-    if (boost::icontains(header_value, "gzip"))
-    {
-        return http::gzip_rfc1952;
-    }
-    if (boost::icontains(header_value, "deflate"))
-    {
-        return http::deflate_rfc1951;
-    }
-    return http::no_compression;
-}
-
-} // namespace
-
 /// Start the first asynchronous operation for the connection.
 void Connection::start()
 {
@@ -65,8 +41,7 @@ void Connection::start()
     }
 }
 
-void Connection::handle_read(const boost::system::error_code &error,
-                             std::size_t /*bytes_transferred*/)
+void Connection::handle_read(const boost::system::error_code &error, std::size_t bytes_transferred)
 {
     if (error)
     {
@@ -85,48 +60,20 @@ void Connection::handle_read(const boost::system::error_code &error,
         timer.expires_from_now(boost::posix_time::seconds(0));
     }
 
-    boost::beast::error_code ec;
-    http_request_parser->put(boost::asio::buffer(incoming_data_buffer), ec);
     // no error detected, let's parse the request
     http::compression_type compression_type(http::no_compression);
-
-    if (ec)
-    {
-        if (ec == boost::beast::http::error::need_more)
-        {
-            const auto current_size = incoming_data_buffer.size();
-            incoming_data_buffer.resize(incoming_data_buffer.size() + CHUNK_SIZE, 0);
-            // we don't have a result yet, so continue reading
-            TCP_socket.async_read_some(
-                boost::asio::buffer(incoming_data_buffer.data() + current_size, CHUNK_SIZE),
-                boost::bind(&Connection::handle_read,
-                            this->shared_from_this(),
-                            boost::asio::placeholders::error,
-                            boost::asio::placeholders::bytes_transferred));
-        }
-        else
-        {
-            // request is not parseable
-            current_reply = http::reply::stock_reply(http::reply::bad_request);
-
-            boost::asio::async_write(TCP_socket,
-                                     current_reply.to_buffers(),
-                                     boost::bind(&Connection::handle_write,
-                                                 this->shared_from_this(),
-                                                 boost::asio::placeholders::error));
-        }
-    }
-    else
+    RequestParser::RequestStatus result;
+    std::tie(result, compression_type) =
+        request_parser.parse(current_request,
+                             incoming_data_buffer.data(),
+                             incoming_data_buffer.data() + bytes_transferred);
+
+    // the request has been parsed
+    if (result == RequestParser::RequestStatus::valid)
     {
-        // the request has been parsed
-        const auto &message = http_request_parser->get();
-        compression_type = select_compression(message);
-
-        fill_request(message, current_request);
 
         boost::system::error_code ec;
         current_request.endpoint = TCP_socket.remote_endpoint(ec).address();
-
         if (ec)
         {
             util::Log(logDEBUG) << "Socket remote endpoint error: " << ec.message();
@@ -180,6 +127,25 @@ void Connection::handle_read(const boost::system::error_code &error,
                                              this->shared_from_this(),
                                              boost::asio::placeholders::error));
     }
+    else if (result == RequestParser::RequestStatus::invalid)
+    { // request is not parseable
+        current_reply = http::reply::stock_reply(http::reply::bad_request);
+
+        boost::asio::async_write(TCP_socket,
+                                 current_reply.to_buffers(),
+                                 boost::bind(&Connection::handle_write,
+                                             this->shared_from_this(),
+                                             boost::asio::placeholders::error));
+    }
+    else
+    {
+        // we don't have a result yet, so continue reading
+        TCP_socket.async_read_some(boost::asio::buffer(incoming_data_buffer),
+                                   boost::bind(&Connection::handle_read,
+                                               this->shared_from_this(),
+                                               boost::asio::placeholders::error,
+                                               boost::asio::placeholders::bytes_transferred));
+    }
 }
 
 /// Handle completion of a write operation.
@@ -192,9 +158,8 @@ void Connection::handle_write(const boost::system::error_code &error)
             --processed_requests;
             current_request = http::request();
             current_reply = http::reply();
-            http_request_parser.emplace();
-            http_request_parser->header_limit(std::numeric_limits<std::uint32_t>::max());
-            incoming_data_buffer.resize(CHUNK_SIZE, 0);
+            request_parser = RequestParser();
+            incoming_data_buffer = boost::array<char, 8192>();
             output_buffer.clear();
             this->start();
         }
@@ -255,15 +220,5 @@ std::vector<char> Connection::compress_buffers(const std::vector<char> &uncompre
 
     return compressed_data;
 }
-
-void Connection::fill_request(const RequestParser::value_type &http_message,
-                              http::request &current_request)
-{
-    current_request.uri = http_message.target().to_string();
-    current_request.agent = http_message[boost::beast::http::field::user_agent].to_string();
-    current_request.referrer = http_message[boost::beast::http::field::referer].to_string();
-    current_request.connection = http_message[boost::beast::http::field::connection].to_string();
-}
-
 } // namespace server
 } // namespace osrm