icinga2/lib/remote/httpserverconnection.cpp
Michael Friedrich c5aa978912 Rewrite error handling in HttpServerConnection#EnsureValidHeaders()
Throwing local exceptions unnecessarily pollutes the exception
stack with immediate unwinding. Avoid this pattern at all cost within
Boost.Coroutines. MSVC may handle exceptions differently and cause
problems with stack unwinding.

refs #7431
refs #7351
2019-09-09 11:03:21 +02:00

583 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 = false;
String errorMsg;
boost::system::error_code ec;
http::async_read_header(stream, buf, parser, yc[ec]);
if (ec) {
errorMsg = ec.message();
httpError = true;
}
switch (parser.get().version()) {
case 10:
case 11:
break;
default:
errorMsg = "Unsupported HTTP version";
}
if (!errorMsg.IsEmpty() || httpError) {
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: ") + errorMsg }
}));
} else {
response.set(http::field::content_type, "text/html");
response.body() = String("<h1>Bad Request</h1><p><pre>") + errorMsg + "</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;
Defer disconnect ([this]() { Disconnect(); });
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();
}
}
}
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;
}
}
}