cloudflare/cloudflared
Publicmirrored from https://github.com/cloudflare/cloudflaredAvailable
dbconnect/proxy.go
271lines · modeblame
759cd019Ashcon Partovi6 years ago | 1 | package dbconnect |
| 2 | | |
| 3 | import ( | |
| 4 | "context" | |
| 5 | "encoding/json" | |
| 6 | "fmt" | |
| 7 | "io" | |
| 8 | "net" | |
| 9 | "net/http" | |
| 10 | "net/url" | |
| 11 | "time" | |
| 12 | | |
| 13 | "github.com/cloudflare/cloudflared/hello" | |
| 14 | "github.com/cloudflare/cloudflared/validation" | |
| 15 | "github.com/gorilla/mux" | |
| 16 | "github.com/pkg/errors" | |
| 17 | "github.com/sirupsen/logrus" | |
| 18 | ) | |
| 19 | | |
| 20 | // Proxy is an HTTP server that proxies requests to a Client. | |
| 21 | type Proxy struct { | |
| 22 | client Client | |
| 23 | accessValidator *validation.Access | |
| 24 | logger *logrus.Logger | |
| 25 | } | |
| 26 | | |
| 27 | // NewInsecureProxy creates a Proxy that talks to a Client at an origin. | |
| 28 | // | |
| 29 | // In insecure mode, the Proxy will allow all Command requests. | |
| 30 | func NewInsecureProxy(ctx context.Context, origin string) (*Proxy, error) { | |
| 31 | originURL, err := url.Parse(origin) | |
| 32 | if err != nil { | |
| 33 | return nil, errors.Wrap(err, "must provide a valid database url") | |
| 34 | } | |
| 35 | | |
| 36 | client, err := NewClient(ctx, originURL) | |
| 37 | if err != nil { | |
| 38 | return nil, err | |
| 39 | } | |
| 40 | | |
| 41 | err = client.Ping(ctx) | |
| 42 | if err != nil { | |
| 43 | return nil, errors.Wrap(err, "could not connect to the database") | |
| 44 | } | |
| 45 | | |
| 46 | return &Proxy{client, nil, logrus.New()}, nil | |
| 47 | } | |
| 48 | | |
| 49 | // NewSecureProxy creates a Proxy that talks to a Client at an origin. | |
| 50 | // | |
| 51 | // In secure mode, the Proxy will reject any Command requests that are | |
| 52 | // not authenticated by Cloudflare Access with a valid JWT. | |
| 53 | func NewSecureProxy(ctx context.Context, origin, authDomain, applicationAUD string) (*Proxy, error) { | |
| 54 | proxy, err := NewInsecureProxy(ctx, origin) | |
| 55 | if err != nil { | |
| 56 | return nil, err | |
| 57 | } | |
| 58 | | |
| 59 | validator, err := validation.NewAccessValidator(ctx, authDomain, authDomain, applicationAUD) | |
| 60 | if err != nil { | |
| 61 | return nil, err | |
| 62 | } | |
| 63 | | |
| 64 | proxy.accessValidator = validator | |
| 65 | | |
| 66 | return proxy, err | |
| 67 | } | |
| 68 | | |
| 69 | // IsInsecure gets whether the Proxy will accept a Command from any source. | |
| 70 | func (proxy *Proxy) IsInsecure() bool { | |
| 71 | return proxy.accessValidator == nil | |
| 72 | } | |
| 73 | | |
| 74 | // IsAllowed checks whether a http.Request is allowed to receive data. | |
| 75 | // | |
| 76 | // By default, requests must pass through Cloudflare Access for authentication. | |
| 77 | // If the proxy is explcitly set to insecure mode, all requests will be allowed. | |
| 78 | func (proxy *Proxy) IsAllowed(r *http.Request, verbose ...bool) bool { | |
| 79 | if proxy.IsInsecure() { | |
| 80 | return true | |
| 81 | } | |
| 82 | | |
| 83 | // Access and Tunnel should prevent bad JWTs from even reaching the origin, | |
| 84 | // but validate tokens anyway as an abundance of caution. | |
| 85 | err := proxy.accessValidator.ValidateRequest(r.Context(), r) | |
| 86 | if err == nil { | |
| 87 | return true | |
| 88 | } | |
| 89 | | |
| 90 | // Warn administrators that invalid JWTs are being rejected. This is indicative | |
| 91 | // of either a misconfiguration of the CLI or a massive failure of upstream systems. | |
| 92 | if len(verbose) > 0 { | |
| 93 | proxy.httpLog(r, err).Error("Failed JWT authentication") | |
| 94 | } | |
| 95 | | |
| 96 | return false | |
| 97 | } | |
| 98 | | |
| 99 | // Start the Proxy at a given address and notify the listener channel when the server is online. | |
| 100 | func (proxy *Proxy) Start(ctx context.Context, addr string, listenerC chan<- net.Listener) error { | |
| 101 | // STOR-611: use a seperate listener and consider web socket support. | |
| 102 | httpListener, err := hello.CreateTLSListener(addr) | |
| 103 | if err != nil { | |
| 104 | return errors.Wrapf(err, "could not create listener at %s", addr) | |
| 105 | } | |
| 106 | | |
| 107 | errC := make(chan error) | |
| 108 | defer close(errC) | |
| 109 | | |
| 110 | // Starts the HTTP server and begins to serve requests. | |
| 111 | go func() { | |
| 112 | errC <- proxy.httpListen(ctx, httpListener) | |
| 113 | }() | |
| 114 | | |
| 115 | // Continually ping the server until it comes online or 10 attempts fail. | |
| 116 | go func() { | |
| 117 | var err error | |
| 118 | for i := 0; i < 10; i++ { | |
| 119 | _, err = http.Get("http://" + httpListener.Addr().String()) | |
| 120 | | |
| 121 | // Once no error was detected, notify the listener channel and return. | |
| 122 | if err == nil { | |
| 123 | listenerC <- httpListener | |
| 124 | return | |
| 125 | } | |
| 126 | | |
| 127 | // Backoff between requests to ping the server. | |
| 128 | <-time.After(1 * time.Second) | |
| 129 | } | |
| 130 | errC <- errors.Wrap(err, "took too long for the http server to start") | |
| 131 | }() | |
| 132 | | |
| 133 | return <-errC | |
| 134 | } | |
| 135 | | |
| 136 | // httpListen starts the httpServer and blocks until the context closes. | |
| 137 | func (proxy *Proxy) httpListen(ctx context.Context, listener net.Listener) error { | |
| 138 | httpServer := &http.Server{ | |
| 139 | Addr: listener.Addr().String(), | |
| 140 | Handler: proxy.httpRouter(), | |
| 141 | ReadTimeout: 10 * time.Second, | |
| 142 | WriteTimeout: 60 * time.Second, | |
| 143 | IdleTimeout: 60 * time.Second, | |
| 144 | } | |
| 145 | | |
| 146 | go func() { | |
| 147 | <-ctx.Done() | |
| 148 | httpServer.Close() | |
| 149 | listener.Close() | |
| 150 | }() | |
| 151 | | |
| 152 | return httpServer.Serve(listener) | |
| 153 | } | |
| 154 | | |
| 155 | // httpRouter creates a mux.Router for the Proxy. | |
| 156 | func (proxy *Proxy) httpRouter() *mux.Router { | |
| 157 | router := mux.NewRouter() | |
| 158 | | |
| 159 | router.HandleFunc("/ping", proxy.httpPing()).Methods("GET", "HEAD") | |
| 160 | router.HandleFunc("/submit", proxy.httpSubmit()).Methods("POST") | |
| 161 | | |
| 162 | return router | |
| 163 | } | |
| 164 | | |
| 165 | // httpPing tests the connection to the database. | |
| 166 | // | |
| 167 | // By default, this endpoint is unauthenticated to allow for health checks. | |
| 168 | // To enable authentication, Cloudflare Access must be enabled on this route. | |
| 169 | func (proxy *Proxy) httpPing() http.HandlerFunc { | |
| 170 | return func(w http.ResponseWriter, r *http.Request) { | |
| 171 | ctx := r.Context() | |
| 172 | err := proxy.client.Ping(ctx) | |
| 173 | | |
| 174 | if err == nil { | |
| 175 | proxy.httpRespond(w, r, http.StatusOK, "") | |
| 176 | } else { | |
| 177 | proxy.httpRespondErr(w, r, http.StatusInternalServerError, err) | |
| 178 | } | |
| 179 | } | |
| 180 | } | |
| 181 | | |
| 182 | // httpSubmit sends a command to the database and returns its response. | |
| 183 | // | |
| 184 | // By default, this endpoint will reject requests that do not pass through Cloudflare Access. | |
| 185 | // To disable authentication, the --insecure flag must be specified in the command line. | |
| 186 | func (proxy *Proxy) httpSubmit() http.HandlerFunc { | |
| 187 | return func(w http.ResponseWriter, r *http.Request) { | |
| 188 | if !proxy.IsAllowed(r, true) { | |
| 189 | proxy.httpRespondErr(w, r, http.StatusForbidden, fmt.Errorf("")) | |
| 190 | return | |
| 191 | } | |
| 192 | | |
| 193 | var cmd Command | |
| 194 | err := json.NewDecoder(r.Body).Decode(&cmd) | |
| 195 | if err != nil { | |
| 196 | proxy.httpRespondErr(w, r, http.StatusBadRequest, err) | |
| 197 | return | |
| 198 | } | |
| 199 | | |
| 200 | ctx := r.Context() | |
| 201 | data, err := proxy.client.Submit(ctx, &cmd) | |
| 202 | | |
| 203 | if err != nil { | |
| 204 | proxy.httpRespondErr(w, r, http.StatusUnprocessableEntity, err) | |
| 205 | return | |
| 206 | } | |
| 207 | | |
| 208 | w.Header().Set("Content-type", "application/json") | |
| 209 | err = json.NewEncoder(w).Encode(data) | |
| 210 | if err != nil { | |
| 211 | proxy.httpRespondErr(w, r, http.StatusInternalServerError, err) | |
| 212 | } | |
| 213 | } | |
| 214 | } | |
| 215 | | |
| 216 | // httpRespond writes a status code and string response to the response writer. | |
| 217 | func (proxy *Proxy) httpRespond(w http.ResponseWriter, r *http.Request, status int, message string) { | |
| 218 | w.WriteHeader(status) | |
| 219 | | |
| 220 | // Only expose the message detail of the reponse if the request is not HEAD | |
| 221 | // and the user is authenticated. For example, this prevents an unauthenticated | |
| 222 | // failed health check from accidentally leaking sensitive information about the Client. | |
| 223 | if r.Method != http.MethodHead && proxy.IsAllowed(r) { | |
| 224 | if message == "" { | |
| 225 | message = http.StatusText(status) | |
| 226 | } | |
| 227 | fmt.Fprint(w, message) | |
| 228 | } | |
| 229 | } | |
| 230 | | |
| 231 | // httpRespondErr is similar to httpRespond, except it formats errors to be more friendly. | |
| 232 | func (proxy *Proxy) httpRespondErr(w http.ResponseWriter, r *http.Request, defaultStatus int, err error) { | |
| 233 | status, err := httpError(defaultStatus, err) | |
| 234 | | |
| 235 | proxy.httpRespond(w, r, status, err.Error()) | |
| 236 | if len(err.Error()) > 0 { | |
| 237 | proxy.httpLog(r, err).Warn("Database proxy error") | |
| 238 | } | |
| 239 | } | |
| 240 | | |
| 241 | // httpLog returns a logrus.Entry that is formatted to output a request Cf-ray. | |
| 242 | func (proxy *Proxy) httpLog(r *http.Request, err error) *logrus.Entry { | |
| 243 | return proxy.logger.WithContext(r.Context()).WithField("CF-RAY", r.Header.Get("Cf-ray")).WithError(err) | |
| 244 | } | |
| 245 | | |
| 246 | // httpError extracts common errors and returns an status code and friendly error. | |
| 247 | func httpError(defaultStatus int, err error) (int, error) { | |
| 248 | if err == nil { | |
| 249 | return http.StatusNotImplemented, fmt.Errorf("error expected but found none") | |
| 250 | } | |
| 251 | | |
| 252 | if err == io.EOF { | |
| 253 | return http.StatusBadRequest, fmt.Errorf("request body cannot be empty") | |
| 254 | } | |
| 255 | | |
| 256 | if err == context.DeadlineExceeded { | |
| 257 | return http.StatusRequestTimeout, err | |
| 258 | } | |
| 259 | | |
| 260 | _, ok := err.(net.Error) | |
| 261 | if ok { | |
| 262 | return http.StatusRequestTimeout, err | |
| 263 | } | |
| 264 | | |
| 265 | if err == context.Canceled { | |
| 266 | // Does not exist in Golang, but would be: http.StatusClientClosedWithoutResponse | |
| 267 | return 444, err | |
| 268 | } | |
| 269 | | |
| 270 | return defaultStatus, err | |
| 271 | } |