icinga2/lib/remote/httpserverconnection.cpp
Michael Friedrich 17d4d17307 Avoid the Defer-Disconnect destructor pattern with Boost.Coroutines
Exceptions in Disconnect() might be thrown (this has been reworked
into error_code locally) which are swallowed inside the Destructor
for being dangerous. On the other hand, swallowing them may
corrupt the stack unwinding operation from the coroutine layer.

The best is to avoid Defer inside lib/remote and call Disconnect()
directly after breaking from other operations.

refs #7351
refs #7431
2019-09-09 10:57:13 +02:00

589 lines
15 KiB
C++

/* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
#include "remote/httpserverconnection.hpp"
#include "remote/httphandler.hpp"
#include "remote/httputility.hpp"
#include "remote/apilistener.hpp"
#include "remote/apifunction.hpp"
#include "remote/jsonrpc.hpp"
#include "base/application.hpp"
#include "base/base64.hpp"
#include "base/convert.hpp"
#include "base/configtype.hpp"
#include "base/defer.hpp"
#include "base/exception.hpp"
#include "base/io-engine.hpp"
#include "base/logger.hpp"
#include "base/objectlock.hpp"
#include "base/timer.hpp"
#include "base/tlsstream.hpp"
#include "base/utility.hpp"
#include <limits>
#include <memory>
#include <stdexcept>
#include <boost/asio/io_service.hpp>
#include <boost/asio/spawn.hpp>
#include <boost/beast/core.hpp>
#include <boost/beast/http.hpp>
#include <boost/system/system_error.hpp>
#include <boost/thread/once.hpp>
using namespace icinga;
auto const l_ServerHeader ("Icinga/" + Application::GetAppVersion());
HttpServerConnection::HttpServerConnection(const String& identity, bool authenticated, const std::shared_ptr<AsioTlsStream>& stream)
: HttpServerConnection(identity, authenticated, stream, IoEngine::Get().GetIoService())
{
}
HttpServerConnection::HttpServerConnection(const String& identity, bool authenticated, const std::shared_ptr<AsioTlsStream>& stream, boost::asio::io_service& io)
: m_Stream(stream), m_Seen(Utility::GetTime()), m_IoStrand(io), m_ShuttingDown(false), m_HasStartedStreaming(false),
m_CheckLivenessTimer(io)
{
if (authenticated) {
m_ApiUser = ApiUser::GetByClientCN(identity);
}
{
std::ostringstream address;
auto endpoint (stream->lowest_layer().remote_endpoint());
address << '[' << endpoint.address() << "]:" << endpoint.port();
m_PeerAddress = address.str();
}
}
void HttpServerConnection::Start()
{
namespace asio = boost::asio;
HttpServerConnection::Ptr keepAlive (this);
asio::spawn(m_IoStrand, [this, keepAlive](asio::yield_context yc) { ProcessMessages(yc); });
asio::spawn(m_IoStrand, [this, keepAlive](asio::yield_context yc) { CheckLiveness(yc); });
}
void HttpServerConnection::Disconnect()
{
namespace asio = boost::asio;
HttpServerConnection::Ptr keepAlive (this);
asio::spawn(m_IoStrand, [this, keepAlive](asio::yield_context yc) {
if (!m_ShuttingDown) {
m_ShuttingDown = true;
Log(LogInformation, "HttpServerConnection")
<< "HTTP client disconnected (from " << m_PeerAddress << ")";
/*
* Do not swallow exceptions in a coroutine.
* https://github.com/Icinga/icinga2/issues/7351
* We must not catch `detail::forced_unwind exception` as
* this is used for unwinding the stack.
*
* Just use the error_code dummy here.
*/
boost::system::error_code ec;
m_Stream->next_layer().async_shutdown(yc[ec]);
m_Stream->lowest_layer().shutdown(m_Stream->lowest_layer().shutdown_both, ec);
m_Stream->lowest_layer().cancel(ec);
m_CheckLivenessTimer.cancel();
auto listener (ApiListener::GetInstance());
if (listener) {
CpuBoundWork removeHttpClient (yc);
listener->RemoveHttpClient(this);
}
}
});
}
void HttpServerConnection::StartStreaming()
{
namespace asio = boost::asio;
m_HasStartedStreaming = true;
HttpServerConnection::Ptr keepAlive (this);
asio::spawn(m_IoStrand, [this, keepAlive](asio::yield_context yc) {
if (!m_ShuttingDown) {
char buf[128];
asio::mutable_buffer readBuf (buf, 128);
boost::system::error_code ec;
do {
m_Stream->async_read_some(readBuf, yc[ec]);
} while (!ec);
Disconnect();
}
});
}
bool HttpServerConnection::Disconnected()
{
return m_ShuttingDown;
}
static inline
bool EnsureValidHeaders(
AsioTlsStream& stream,
boost::beast::flat_buffer& buf,
boost::beast::http::parser<true, boost::beast::http::string_body>& parser,
boost::beast::http::response<boost::beast::http::string_body>& response,
boost::asio::yield_context& yc
)
{
namespace http = boost::beast::http;
bool httpError = true;
try {
boost::system::error_code ec;
http::async_read_header(stream, buf, parser, yc[ec]);
if (ec) {
/**
* Unfortunately there's no way to tell an HTTP protocol error
* from an error on a lower layer:
*
* <https://github.com/boostorg/beast/issues/643>
*/
throw std::invalid_argument(ec.message());
}
httpError = false;
switch (parser.get().version()) {
case 10:
case 11:
break;
default:
throw std::invalid_argument("Unsupported HTTP version");
}
} catch (const std::invalid_argument& ex) {
response.result(http::status::bad_request);
if (!httpError && parser.get()[http::field::accept] == "application/json") {
HttpUtility::SendJsonBody(response, nullptr, new Dictionary({
{ "error", 400 },
{ "status", String("Bad Request: ") + ex.what() }
}));
} else {
response.set(http::field::content_type, "text/html");
response.body() = String("<h1>Bad Request</h1><p><pre>") + ex.what() + "</pre></p>";
response.set(http::field::content_length, response.body().size());
}
response.set(http::field::connection, "close");
boost::system::error_code ec;
http::async_write(stream, response, yc[ec]);
stream.async_flush(yc[ec]);
return false;
}
return true;
}
static inline
void HandleExpect100(
AsioTlsStream& stream,
boost::beast::http::request<boost::beast::http::string_body>& request,
boost::asio::yield_context& yc
)
{
namespace http = boost::beast::http;
if (request[http::field::expect] == "100-continue") {
http::response<http::string_body> response;
response.result(http::status::continue_);
boost::system::error_code ec;
http::async_write(stream, response, yc[ec]);
stream.async_flush(yc[ec]);
}
}
static inline
bool HandleAccessControl(
AsioTlsStream& stream,
boost::beast::http::request<boost::beast::http::string_body>& request,
boost::beast::http::response<boost::beast::http::string_body>& response,
boost::asio::yield_context& yc
)
{
namespace http = boost::beast::http;
auto listener (ApiListener::GetInstance());
if (listener) {
auto headerAllowOrigin (listener->GetAccessControlAllowOrigin());
if (headerAllowOrigin) {
CpuBoundWork allowOriginHeader (yc);
auto allowedOrigins (headerAllowOrigin->ToSet<String>());
if (!allowedOrigins.empty()) {
auto& origin (request[http::field::origin]);
if (allowedOrigins.find(origin.to_string()) != allowedOrigins.end()) {
response.set(http::field::access_control_allow_origin, origin);
}
allowOriginHeader.Done();
response.set(http::field::access_control_allow_credentials, "true");
if (request.method() == http::verb::options && !request[http::field::access_control_request_method].empty()) {
response.result(http::status::ok);
response.set(http::field::access_control_allow_methods, "GET, POST, PUT, DELETE");
response.set(http::field::access_control_allow_headers, "Authorization, X-HTTP-Method-Override");
response.body() = "Preflight OK";
response.set(http::field::content_length, response.body().size());
response.set(http::field::connection, "close");
boost::system::error_code ec;
http::async_write(stream, response, yc[ec]);
stream.async_flush(yc[ec]);
return false;
}
}
}
}
return true;
}
static inline
bool EnsureAcceptHeader(
AsioTlsStream& stream,
boost::beast::http::request<boost::beast::http::string_body>& request,
boost::beast::http::response<boost::beast::http::string_body>& response,
boost::asio::yield_context& yc
)
{
namespace http = boost::beast::http;
if (request.method() != http::verb::get && request[http::field::accept] != "application/json") {
response.result(http::status::bad_request);
response.set(http::field::content_type, "text/html");
response.body() = "<h1>Accept header is missing or not set to 'application/json'.</h1>";
response.set(http::field::content_length, response.body().size());
response.set(http::field::connection, "close");
boost::system::error_code ec;
http::async_write(stream, response, yc[ec]);
stream.async_flush(yc[ec]);
return false;
}
return true;
}
static inline
bool EnsureAuthenticatedUser(
AsioTlsStream& stream,
boost::beast::http::request<boost::beast::http::string_body>& request,
ApiUser::Ptr& authenticatedUser,
boost::beast::http::response<boost::beast::http::string_body>& response,
boost::asio::yield_context& yc
)
{
namespace http = boost::beast::http;
if (!authenticatedUser) {
Log(LogWarning, "HttpServerConnection")
<< "Unauthorized request: " << request.method_string() << ' ' << request.target();
response.result(http::status::unauthorized);
response.set(http::field::www_authenticate, "Basic realm=\"Icinga 2\"");
response.set(http::field::connection, "close");
if (request[http::field::accept] == "application/json") {
HttpUtility::SendJsonBody(response, nullptr, new Dictionary({
{ "error", 401 },
{ "status", "Unauthorized. Please check your user credentials." }
}));
} else {
response.set(http::field::content_type, "text/html");
response.body() = "<h1>Unauthorized. Please check your user credentials.</h1>";
response.set(http::field::content_length, response.body().size());
}
boost::system::error_code ec;
http::async_write(stream, response, yc[ec]);
stream.async_flush(yc[ec]);
return false;
}
return true;
}
static inline
bool EnsureValidBody(
AsioTlsStream& stream,
boost::beast::flat_buffer& buf,
boost::beast::http::parser<true, boost::beast::http::string_body>& parser,
ApiUser::Ptr& authenticatedUser,
boost::beast::http::response<boost::beast::http::string_body>& response,
boost::asio::yield_context& yc
)
{
namespace http = boost::beast::http;
{
size_t maxSize = 1024 * 1024;
Array::Ptr permissions = authenticatedUser->GetPermissions();
if (permissions) {
CpuBoundWork evalPermissions (yc);
ObjectLock olock(permissions);
for (const Value& permissionInfo : permissions) {
String permission;
if (permissionInfo.IsObjectType<Dictionary>()) {
permission = static_cast<Dictionary::Ptr>(permissionInfo)->Get("permission");
} else {
permission = permissionInfo;
}
static std::vector<std::pair<String, size_t>> specialContentLengthLimits {
{ "config/modify", 512 * 1024 * 1024 }
};
for (const auto& limitInfo : specialContentLengthLimits) {
if (limitInfo.second <= maxSize) {
continue;
}
if (Utility::Match(permission, limitInfo.first)) {
maxSize = limitInfo.second;
}
}
}
}
parser.body_limit(maxSize);
}
boost::system::error_code ec;
http::async_read(stream, buf, parser, yc[ec]);
if (ec) {
/**
* Unfortunately there's no way to tell an HTTP protocol error
* from an error on a lower layer:
*
* <https://github.com/boostorg/beast/issues/643>
*/
response.result(http::status::bad_request);
if (parser.get()[http::field::accept] == "application/json") {
HttpUtility::SendJsonBody(response, nullptr, new Dictionary({
{ "error", 400 },
{ "status", String("Bad Request: ") + ec.message() }
}));
} else {
response.set(http::field::content_type, "text/html");
response.body() = String("<h1>Bad Request</h1><p><pre>") + ec.message() + "</pre></p>";
response.set(http::field::content_length, response.body().size());
}
response.set(http::field::connection, "close");
http::async_write(stream, response, yc[ec]);
stream.async_flush(yc[ec]);
return false;
}
return true;
}
static inline
bool ProcessRequest(
AsioTlsStream& stream,
boost::beast::http::request<boost::beast::http::string_body>& request,
ApiUser::Ptr& authenticatedUser,
boost::beast::http::response<boost::beast::http::string_body>& response,
HttpServerConnection& server,
bool& hasStartedStreaming,
boost::asio::yield_context& yc
)
{
namespace http = boost::beast::http;
try {
CpuBoundWork handlingRequest (yc);
HttpHandler::ProcessRequest(stream, authenticatedUser, request, response, yc, server);
} catch (const std::exception& ex) {
if (hasStartedStreaming) {
return false;
}
http::response<http::string_body> response;
HttpUtility::SendJsonError(response, nullptr, 500, "Unhandled exception" , DiagnosticInformation(ex));
boost::system::error_code ec;
http::async_write(stream, response, yc[ec]);
stream.async_flush(yc[ec]);
return true;
}
if (hasStartedStreaming) {
return false;
}
boost::system::error_code ec;
http::async_write(stream, response, yc[ec]);
stream.async_flush(yc[ec]);
return true;
}
void HttpServerConnection::ProcessMessages(boost::asio::yield_context yc)
{
namespace beast = boost::beast;
namespace http = beast::http;
try {
beast::flat_buffer buf;
for (;;) {
m_Seen = Utility::GetTime();
http::parser<true, http::string_body> parser;
http::response<http::string_body> response;
parser.header_limit(1024 * 1024);
parser.body_limit(-1);
response.set(http::field::server, l_ServerHeader);
// Best practice is to always reset the buffer.
buf = {};
if (!EnsureValidHeaders(*m_Stream, buf, parser, response, yc)) {
break;
}
m_Seen = Utility::GetTime();
auto& request (parser.get());
{
auto method (http::string_to_verb(request["X-Http-Method-Override"]));
if (method != http::verb::unknown) {
request.method(method);
}
}
HandleExpect100(*m_Stream, request, yc);
auto authenticatedUser (m_ApiUser);
if (!authenticatedUser) {
CpuBoundWork fetchingAuthenticatedUser (yc);
authenticatedUser = ApiUser::GetByAuthHeader(request[http::field::authorization].to_string());
}
Log(LogInformation, "HttpServerConnection")
<< "Request: " << request.method_string() << ' ' << request.target()
<< " (from " << m_PeerAddress
<< "), user: " << (authenticatedUser ? authenticatedUser->GetName() : "<unauthenticated>")
<< ", agent: " << request[http::field::user_agent] << ")."; //operator[] - Returns the value for a field, or "" if it does not exist.
if (!HandleAccessControl(*m_Stream, request, response, yc)) {
break;
}
if (!EnsureAcceptHeader(*m_Stream, request, response, yc)) {
break;
}
if (!EnsureAuthenticatedUser(*m_Stream, request, authenticatedUser, response, yc)) {
break;
}
// Best practice is to always reset the buffer.
buf = {};
if (!EnsureValidBody(*m_Stream, buf, parser, authenticatedUser, response, yc)) {
break;
}
m_Seen = std::numeric_limits<decltype(m_Seen)>::max();
if (!ProcessRequest(*m_Stream, request, authenticatedUser, response, *this, m_HasStartedStreaming, yc)) {
break;
}
if (request.version() != 11 || request[http::field::connection] == "close") {
break;
}
}
} catch (const std::exception& ex) {
if (!m_ShuttingDown) {
Log(LogCritical, "HttpServerConnection")
<< "Unhandled exception while processing HTTP request: " << ex.what();
}
}
Disconnect();
}
void HttpServerConnection::CheckLiveness(boost::asio::yield_context yc)
{
boost::system::error_code ec;
for (;;) {
m_CheckLivenessTimer.expires_from_now(boost::posix_time::seconds(5));
m_CheckLivenessTimer.async_wait(yc[ec]);
if (m_ShuttingDown) {
break;
}
if (m_Seen < Utility::GetTime() - 10) {
Log(LogInformation, "HttpServerConnection")
<< "No messages for HTTP connection have been received in the last 10 seconds.";
Disconnect();
break;
}
}
}