| // Copyright 2020 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "system-proxy/proxy_connect_job.h" |
| |
| #include <algorithm> |
| #include <utility> |
| #include <vector> |
| |
| #include <curl/easy.h> |
| |
| #include <base/base64.h> |
| #include <base/bind.h> |
| #include <base/bind_helpers.h> |
| #include <base/callback_helpers.h> |
| #include <base/files/file_util.h> |
| #include <base/strings/stringprintf.h> |
| #include <base/strings/string_util.h> |
| #include <base/time/time.h> |
| #include <base/threading/thread.h> |
| #include <base/threading/thread_task_runner_handle.h> |
| #include <brillo/http/http_transport.h> |
| #include <chromeos/patchpanel/net_util.h> |
| #include <chromeos/patchpanel/socket.h> |
| #include <chromeos/patchpanel/socket_forwarder.h> |
| |
| #include "system-proxy/curl_socket.h" |
| #include "system-proxy/http_util.h" |
| |
| // The libpatchpanel-util library overloads << for socket data structures. |
| // By C++'s argument-dependent lookup rules, operators defined in a |
| // different namespace are not visible. We need the using directive to make |
| // the overload available this namespace. |
| using patchpanel::operator<<; |
| |
| namespace { |
| // There's no RFC recomandation for the max size of http request headers but |
| // popular http server implementations (Apache, IIS, Tomcat) set the lower limit |
| // to 8000. |
| constexpr int kMaxHttpRequestHeadersSize = 8000; |
| constexpr base::TimeDelta kCurlConnectTimeout = base::TimeDelta::FromMinutes(2); |
| constexpr base::TimeDelta kWaitClientConnectTimeout = |
| base::TimeDelta::FromMinutes(2); |
| constexpr size_t kMaxBadRequestPrintSize = 120; |
| |
| constexpr int64_t kHttpCodeProxyAuthRequired = 407; |
| |
| // HTTP error codes and messages with origin information for debugging (RFC723, |
| // section 6.1). |
| const std::string_view kHttpBadRequest = |
| "HTTP/1.1 400 Bad Request - Origin: local proxy\r\n\r\n"; |
| const std::string_view kHttpConnectionTimeout = |
| "HTTP/1.1 408 Request Timeout - Origin: local proxy\r\n\r\n"; |
| const std::string_view kHttpInternalServerError = |
| "HTTP/1.1 500 Internal Server Error - Origin: local proxy\r\n\r\n"; |
| const std::string_view kHttpBadGateway = |
| "HTTP/1.1 502 Bad Gateway - Origin: local proxy\r\n\r\n"; |
| const std::string_view kHttpProxyAuthRequired = |
| "HTTP/1.1 407 Credentials required - Origin: local proxy\r\n\r\n"; |
| constexpr char kHttpErrorTunnelFailed[] = |
| "HTTP/1.1 %s Error creating tunnel - Origin: local proxy\r\n\r\n"; |
| } // namespace |
| |
| namespace system_proxy { |
| // CURLOPT_HEADERFUNCTION callback implementation that only returns the headers |
| // from the last response sent by the sever. This is to make sure that we |
| // send back valid HTTP replies and auhentication data from the HTTP messages is |
| // not being leaked to the client. |userdata| is set on the libcurl CURL handle |
| // used to configure the request, using the the CURLOPT_HEADERDATA option. Note, |
| // from the libcurl documentation: This callback is being called for all the |
| // responses received from the proxy server after intiating the connection |
| // request. Multiple responses can be received in an authentication sequence. |
| // Only the last response's headers should be forwarded to the System-proxy |
| // client. The header callback will be called once for each header and only |
| // complete header lines are passed on to the callback. |
| static size_t WriteHeadersCallback(char* contents, |
| size_t size, |
| size_t nmemb, |
| void* userdata) { |
| std::vector<char>* vec = (std::vector<char>*)userdata; |
| |
| // Check if we are receiving a new HTTP message (after the last one was |
| // terminated with an empty line). |
| if (IsEndingWithHttpEmptyLine(base::StringPiece(vec->data(), vec->size()))) { |
| VLOG(1) << "Removing the http reply headers from the server " |
| << base::StringPiece(vec->data(), vec->size()); |
| vec->clear(); |
| } |
| vec->insert(vec->end(), contents, contents + (nmemb * size)); |
| return size * nmemb; |
| } |
| |
| // CONNECT requests may have a reply body. This method will capture the reply |
| // and save it in |userdata|. |userdata| is set on the libcurl CURL handle |
| // used to configure the request, using the the CURLOPT_WRITEDATA option. |
| static size_t WriteCallback(char* contents, |
| size_t size, |
| size_t nmemb, |
| void* userdata) { |
| std::vector<char>* vec = (std::vector<char>*)userdata; |
| vec->insert(vec->end(), contents, contents + (nmemb * size)); |
| return size * nmemb; |
| } |
| |
| ProxyConnectJob::ProxyConnectJob( |
| std::unique_ptr<patchpanel::Socket> socket, |
| const std::string& credentials, |
| ResolveProxyCallback resolve_proxy_callback, |
| OnConnectionSetupFinishedCallback setup_finished_callback) |
| : credentials_(credentials), |
| resolve_proxy_callback_(std::move(resolve_proxy_callback)), |
| setup_finished_callback_(std::move(setup_finished_callback)), |
| // Safe to use |base::Unretained| because the callback will be canceled |
| // when it goes out of scope. |
| client_connect_timeout_callback_(base::Bind( |
| &ProxyConnectJob::OnClientConnectTimeout, base::Unretained(this))) { |
| client_socket_ = std::move(socket); |
| } |
| |
| ProxyConnectJob::~ProxyConnectJob() = default; |
| |
| bool ProxyConnectJob::Start() { |
| // Make the socket non-blocking. |
| if (!base::SetNonBlocking(client_socket_->fd())) { |
| PLOG(ERROR) << *this << " Failed to mark the socket as non-blocking."; |
| client_socket_->SendTo(kHttpInternalServerError.data(), |
| kHttpInternalServerError.size()); |
| return false; |
| } |
| base::ThreadTaskRunnerHandle::Get()->PostDelayedTask( |
| FROM_HERE, client_connect_timeout_callback_.callback(), |
| kWaitClientConnectTimeout); |
| read_watcher_ = base::FileDescriptorWatcher::WatchReadable( |
| client_socket_->fd(), base::Bind(&ProxyConnectJob::OnClientReadReady, |
| weak_ptr_factory_.GetWeakPtr())); |
| return true; |
| } |
| |
| void ProxyConnectJob::OnClientReadReady() { |
| if (!read_watcher_) { |
| // The connection has timed out while waiting for the client's HTTP CONNECT |
| // request. See |OnClientConnectTimeout|. |
| return; |
| } |
| client_connect_timeout_callback_.Cancel(); |
| // Stop watching. |
| read_watcher_.reset(); |
| // The first message should be a HTTP CONNECT request. |
| std::vector<char> connect_request; |
| if (!TryReadHttpHeader(&connect_request)) { |
| std::string encoded; |
| base::Base64Encode( |
| base::StringPiece(connect_request.data(), connect_request.size()), |
| &encoded); |
| LOG(ERROR) << *this |
| << " Failure to read proxy CONNECT request. Base 64 encoded " |
| "request message from client: " |
| << encoded; |
| OnError(kHttpBadRequest); |
| return; |
| } |
| base::StringPiece request(connect_request.data(), connect_request.size()); |
| target_url_ = GetUriAuthorityFromHttpHeader(request); |
| if (target_url_.empty()) { |
| LOG(ERROR) |
| << *this |
| << " Failed to extract target url from the HTTP CONNECT request."; |
| OnError(kHttpBadRequest); |
| return; |
| } |
| |
| // The proxy resolution service in Chrome expects a proper URL, formatted as |
| // scheme://host:port. It's safe to assume only https will be used for the |
| // target url. |
| std::move(resolve_proxy_callback_) |
| .Run(base::StringPrintf("https://%s", target_url_.c_str()), |
| base::Bind(&ProxyConnectJob::OnProxyResolution, |
| weak_ptr_factory_.GetWeakPtr())); |
| } |
| |
| bool ProxyConnectJob::TryReadHttpHeader(std::vector<char>* raw_request) { |
| size_t read_byte_count = 0; |
| raw_request->resize(kMaxHttpRequestHeadersSize); |
| |
| // Read byte-by-byte and stop when reading an empty line (only CRLF) or when |
| // exceeding the max buffer size. |
| // TODO(acostinas, chromium:1064536) This may have some measurable performance |
| // impact. We should read larger blocks of data, consume the HTTP headers, |
| // cache the tunneled payload that may have already been included (e.g. TLS |
| // ClientHello) and send it to server after the connection is established. |
| while (read_byte_count < kMaxHttpRequestHeadersSize) { |
| if (client_socket_->RecvFrom(raw_request->data() + read_byte_count, 1) <= |
| 0) { |
| raw_request->resize(std::min(read_byte_count, kMaxBadRequestPrintSize)); |
| return false; |
| } |
| ++read_byte_count; |
| |
| if (IsEndingWithHttpEmptyLine( |
| base::StringPiece(raw_request->data(), read_byte_count))) { |
| raw_request->resize(read_byte_count); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| void ProxyConnectJob::OnProxyResolution( |
| const std::list<std::string>& proxy_servers) { |
| proxy_servers_ = proxy_servers; |
| DoCurlServerConnection(proxy_servers.front()); |
| } |
| |
| void ProxyConnectJob::DoCurlServerConnection(const std::string& proxy_url) { |
| CURL* easyhandle = curl_easy_init(); |
| CURLcode res; |
| curl_socket_t newSocket = -1; |
| |
| if (!easyhandle) { |
| // Unfortunately it's not possible to get the failure reason. |
| LOG(ERROR) << *this << " Failure to create curl handle."; |
| curl_easy_cleanup(easyhandle); |
| OnError(kHttpInternalServerError); |
| return; |
| } |
| curl_easy_setopt(easyhandle, CURLOPT_URL, target_url_.c_str()); |
| std::vector<char> http_response_headers; |
| std::vector<char> http_response_body; |
| if (proxy_url != brillo::http::kDirectProxy) { |
| curl_easy_setopt(easyhandle, CURLOPT_PROXY, proxy_url.c_str()); |
| curl_easy_setopt(easyhandle, CURLOPT_HTTPPROXYTUNNEL, 1L); |
| curl_easy_setopt(easyhandle, CURLOPT_CONNECT_ONLY, 1); |
| // Allow libcurl to pick authentication method. Curl will use the most |
| // secure one the remote site claims to support. |
| curl_easy_setopt(easyhandle, CURLOPT_PROXYAUTH, CURLAUTH_ANY); |
| curl_easy_setopt(easyhandle, CURLOPT_PROXYUSERPWD, credentials_.c_str()); |
| } |
| curl_easy_setopt(easyhandle, CURLOPT_CONNECTTIMEOUT_MS, |
| kCurlConnectTimeout.InMilliseconds()); |
| curl_easy_setopt(easyhandle, CURLOPT_HEADERFUNCTION, WriteHeadersCallback); |
| curl_easy_setopt(easyhandle, CURLOPT_HEADERDATA, &http_response_headers); |
| curl_easy_setopt(easyhandle, CURLOPT_WRITEFUNCTION, WriteCallback); |
| curl_easy_setopt(easyhandle, CURLOPT_WRITEDATA, &http_response_body); |
| |
| res = curl_easy_perform(easyhandle); |
| curl_easy_getinfo(easyhandle, CURLINFO_HTTP_CONNECTCODE, |
| &http_response_code_); |
| |
| if (res != CURLE_OK) { |
| LOG(ERROR) << *this << " curl_easy_perform() failed with error: " |
| << curl_easy_strerror(res); |
| curl_easy_cleanup(easyhandle); |
| |
| SendHttpResponseToClient(/* http_response_headers= */ {}, |
| /* http_response_body= */ {}); |
| std::move(setup_finished_callback_).Run(nullptr, this); |
| return; |
| } |
| // Extract the socket from the curl handle. |
| res = curl_easy_getinfo(easyhandle, CURLINFO_ACTIVESOCKET, &newSocket); |
| if (res != CURLE_OK) { |
| LOG(ERROR) << *this << " Failed to get socket from curl with error: " |
| << curl_easy_strerror(res); |
| curl_easy_cleanup(easyhandle); |
| OnError(kHttpBadGateway); |
| return; |
| } |
| |
| ScopedCurlEasyhandle scoped_handle(easyhandle, FreeCurlEasyhandle()); |
| auto server_conn = std::make_unique<CurlSocket>(base::ScopedFD(newSocket), |
| std::move(scoped_handle)); |
| |
| // Send the server reply to the client. If the connection is successful, the |
| // reply headers should be "HTTP/1.1 200 Connection Established". |
| if (!SendHttpResponseToClient(http_response_headers, http_response_body)) { |
| std::move(setup_finished_callback_).Run(nullptr, this); |
| return; |
| } |
| |
| auto fwd = std::make_unique<patchpanel::SocketForwarder>( |
| base::StringPrintf("%d-%d", client_socket_->fd(), server_conn->fd()), |
| std::move(client_socket_), std::move(server_conn)); |
| // Start forwarding data between sockets. |
| fwd->Start(); |
| std::move(setup_finished_callback_).Run(std::move(fwd), this); |
| } |
| |
| bool ProxyConnectJob::SendHttpResponseToClient( |
| const std::vector<char>& http_response_headers, |
| const std::vector<char>& http_response_body) { |
| if (http_response_code_ == 0) { |
| // No HTTP CONNECT response code is available. |
| return client_socket_->SendTo(kHttpInternalServerError.data(), |
| kHttpInternalServerError.size()); |
| } |
| |
| if (http_response_code_ == kHttpCodeProxyAuthRequired) { |
| // This will be a hint for the user to authenticate via the Browser or |
| // acquire a Kerberos ticket. |
| return client_socket_->SendTo(kHttpProxyAuthRequired.data(), |
| kHttpProxyAuthRequired.size()); |
| } |
| |
| if (http_response_code_ >= 400) { |
| VLOG(1) << "Failed to set up HTTP tunnel with code " << http_response_code_; |
| std::string http_error = base::StringPrintf( |
| kHttpErrorTunnelFailed, std::to_string(http_response_code_).c_str()); |
| return client_socket_->SendTo(http_error.c_str(), http_error.size()); |
| } |
| |
| if (http_response_headers.empty()) { |
| return client_socket_->SendTo(kHttpInternalServerError.data(), |
| kHttpInternalServerError.size()); |
| } |
| |
| VLOG(1) << "Sending server reply to client"; |
| if (!client_socket_->SendTo(http_response_headers.data(), |
| http_response_headers.size())) { |
| PLOG(ERROR) << "Failed to send HTTP server response headers to client"; |
| return false; |
| } |
| if (!http_response_body.empty()) { |
| if (!client_socket_->SendTo(http_response_body.data(), |
| http_response_body.size())) { |
| PLOG(ERROR) << "Failed to send HTTP server response payload to client"; |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| void ProxyConnectJob::OnError(const std::string_view& http_error_message) { |
| client_socket_->SendTo(http_error_message.data(), http_error_message.size()); |
| std::move(setup_finished_callback_).Run(nullptr, this); |
| } |
| |
| void ProxyConnectJob::OnClientConnectTimeout() { |
| // Stop listening for client connect requests. |
| read_watcher_.reset(); |
| LOG(ERROR) << *this |
| << " Connection timed out while waiting for the client to send a " |
| "connect request."; |
| OnError(kHttpConnectionTimeout); |
| } |
| |
| std::ostream& operator<<(std::ostream& stream, const ProxyConnectJob& job) { |
| stream << "{fd: " << job.client_socket_->fd(); |
| if (!job.target_url_.empty()) { |
| stream << ", url: " << job.target_url_; |
| } |
| stream << "}"; |
| return stream; |
| } |
| |
| } // namespace system_proxy |