cloudflare/cloudflared
Publicmirrored from https://github.com/cloudflare/cloudflaredAvailable
dbconnect/proxy.go
279lines · modecode
| 1 | package dbconnect |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/json" |
| 6 | "fmt" |
| 7 | "io" |
| 8 | "net" |
| 9 | "net/http" |
| 10 | "net/url" |
| 11 | "os" |
| 12 | "time" |
| 13 | |
| 14 | "github.com/cloudflare/cloudflared/hello" |
| 15 | "github.com/cloudflare/cloudflared/validation" |
| 16 | "github.com/gorilla/mux" |
| 17 | "github.com/pkg/errors" |
| 18 | "github.com/rs/zerolog" |
| 19 | ) |
| 20 | |
| 21 | const ( |
| 22 | LogFieldCFRay = "cfRay" |
| 23 | ) |
| 24 | |
| 25 | // Proxy is an HTTP server that proxies requests to a Client. |
| 26 | type Proxy struct { |
| 27 | client Client |
| 28 | accessValidator *validation.Access |
| 29 | log *zerolog.Logger |
| 30 | } |
| 31 | |
| 32 | // NewInsecureProxy creates a Proxy that talks to a Client at an origin. |
| 33 | // |
| 34 | // In insecure mode, the Proxy will allow all Command requests. |
| 35 | func NewInsecureProxy(ctx context.Context, origin string) (*Proxy, error) { |
| 36 | originURL, err := url.Parse(origin) |
| 37 | if err != nil { |
| 38 | return nil, errors.Wrap(err, "must provide a valid database url") |
| 39 | } |
| 40 | |
| 41 | client, err := NewClient(ctx, originURL) |
| 42 | if err != nil { |
| 43 | return nil, err |
| 44 | } |
| 45 | |
| 46 | err = client.Ping(ctx) |
| 47 | if err != nil { |
| 48 | return nil, errors.Wrap(err, "could not connect to the database") |
| 49 | } |
| 50 | |
| 51 | log := zerolog.New(os.Stderr).With().Logger() // TODO: Does not obey log configuration |
| 52 | |
| 53 | return &Proxy{client, nil, &log}, nil |
| 54 | } |
| 55 | |
| 56 | // NewSecureProxy creates a Proxy that talks to a Client at an origin. |
| 57 | // |
| 58 | // In secure mode, the Proxy will reject any Command requests that are |
| 59 | // not authenticated by Cloudflare Access with a valid JWT. |
| 60 | func NewSecureProxy(ctx context.Context, origin, authDomain, applicationAUD string) (*Proxy, error) { |
| 61 | proxy, err := NewInsecureProxy(ctx, origin) |
| 62 | if err != nil { |
| 63 | return nil, err |
| 64 | } |
| 65 | |
| 66 | validator, err := validation.NewAccessValidator(ctx, authDomain, authDomain, applicationAUD) |
| 67 | if err != nil { |
| 68 | return nil, err |
| 69 | } |
| 70 | |
| 71 | proxy.accessValidator = validator |
| 72 | |
| 73 | return proxy, err |
| 74 | } |
| 75 | |
| 76 | // IsInsecure gets whether the Proxy will accept a Command from any source. |
| 77 | func (proxy *Proxy) IsInsecure() bool { |
| 78 | return proxy.accessValidator == nil |
| 79 | } |
| 80 | |
| 81 | // IsAllowed checks whether a http.Request is allowed to receive data. |
| 82 | // |
| 83 | // By default, requests must pass through Cloudflare Access for authentication. |
| 84 | // If the proxy is explcitly set to insecure mode, all requests will be allowed. |
| 85 | func (proxy *Proxy) IsAllowed(r *http.Request, verbose ...bool) bool { |
| 86 | if proxy.IsInsecure() { |
| 87 | return true |
| 88 | } |
| 89 | |
| 90 | // Access and Tunnel should prevent bad JWTs from even reaching the origin, |
| 91 | // but validate tokens anyway as an abundance of caution. |
| 92 | err := proxy.accessValidator.ValidateRequest(r.Context(), r) |
| 93 | if err == nil { |
| 94 | return true |
| 95 | } |
| 96 | |
| 97 | // Warn administrators that invalid JWTs are being rejected. This is indicative |
| 98 | // of either a misconfiguration of the CLI or a massive failure of upstream systems. |
| 99 | if len(verbose) > 0 { |
| 100 | proxy.log.Err(err).Str(LogFieldCFRay, proxy.getRayHeader(r)).Msg("dbproxy: Failed JWT authentication") |
| 101 | } |
| 102 | |
| 103 | return false |
| 104 | } |
| 105 | |
| 106 | // Start the Proxy at a given address and notify the listener channel when the server is online. |
| 107 | func (proxy *Proxy) Start(ctx context.Context, addr string, listenerC chan<- net.Listener) error { |
| 108 | // STOR-611: use a seperate listener and consider web socket support. |
| 109 | httpListener, err := hello.CreateTLSListener(addr) |
| 110 | if err != nil { |
| 111 | return errors.Wrapf(err, "could not create listener at %s", addr) |
| 112 | } |
| 113 | |
| 114 | errC := make(chan error) |
| 115 | defer close(errC) |
| 116 | |
| 117 | // Starts the HTTP server and begins to serve requests. |
| 118 | go func() { |
| 119 | errC <- proxy.httpListen(ctx, httpListener) |
| 120 | }() |
| 121 | |
| 122 | // Continually ping the server until it comes online or 10 attempts fail. |
| 123 | go func() { |
| 124 | var err error |
| 125 | for i := 0; i < 10; i++ { |
| 126 | _, err = http.Get("http://" + httpListener.Addr().String()) |
| 127 | |
| 128 | // Once no error was detected, notify the listener channel and return. |
| 129 | if err == nil { |
| 130 | listenerC <- httpListener |
| 131 | return |
| 132 | } |
| 133 | |
| 134 | // Backoff between requests to ping the server. |
| 135 | <-time.After(1 * time.Second) |
| 136 | } |
| 137 | errC <- errors.Wrap(err, "took too long for the http server to start") |
| 138 | }() |
| 139 | |
| 140 | return <-errC |
| 141 | } |
| 142 | |
| 143 | // httpListen starts the httpServer and blocks until the context closes. |
| 144 | func (proxy *Proxy) httpListen(ctx context.Context, listener net.Listener) error { |
| 145 | httpServer := &http.Server{ |
| 146 | Addr: listener.Addr().String(), |
| 147 | Handler: proxy.httpRouter(), |
| 148 | ReadTimeout: 10 * time.Second, |
| 149 | WriteTimeout: 60 * time.Second, |
| 150 | IdleTimeout: 60 * time.Second, |
| 151 | } |
| 152 | |
| 153 | go func() { |
| 154 | <-ctx.Done() |
| 155 | _ = httpServer.Close() |
| 156 | _ = listener.Close() |
| 157 | }() |
| 158 | |
| 159 | return httpServer.Serve(listener) |
| 160 | } |
| 161 | |
| 162 | // httpRouter creates a mux.Router for the Proxy. |
| 163 | func (proxy *Proxy) httpRouter() *mux.Router { |
| 164 | router := mux.NewRouter() |
| 165 | |
| 166 | router.HandleFunc("/ping", proxy.httpPing()).Methods("GET", "HEAD") |
| 167 | router.HandleFunc("/submit", proxy.httpSubmit()).Methods("POST") |
| 168 | |
| 169 | return router |
| 170 | } |
| 171 | |
| 172 | // httpPing tests the connection to the database. |
| 173 | // |
| 174 | // By default, this endpoint is unauthenticated to allow for health checks. |
| 175 | // To enable authentication, Cloudflare Access must be enabled on this route. |
| 176 | func (proxy *Proxy) httpPing() http.HandlerFunc { |
| 177 | return func(w http.ResponseWriter, r *http.Request) { |
| 178 | ctx := r.Context() |
| 179 | err := proxy.client.Ping(ctx) |
| 180 | |
| 181 | if err == nil { |
| 182 | proxy.httpRespond(w, r, http.StatusOK, "") |
| 183 | } else { |
| 184 | proxy.httpRespondErr(w, r, http.StatusInternalServerError, err) |
| 185 | } |
| 186 | } |
| 187 | } |
| 188 | |
| 189 | // httpSubmit sends a command to the database and returns its response. |
| 190 | // |
| 191 | // By default, this endpoint will reject requests that do not pass through Cloudflare Access. |
| 192 | // To disable authentication, the --insecure flag must be specified in the command line. |
| 193 | func (proxy *Proxy) httpSubmit() http.HandlerFunc { |
| 194 | return func(w http.ResponseWriter, r *http.Request) { |
| 195 | if !proxy.IsAllowed(r, true) { |
| 196 | proxy.httpRespondErr(w, r, http.StatusForbidden, fmt.Errorf("")) |
| 197 | return |
| 198 | } |
| 199 | |
| 200 | var cmd Command |
| 201 | err := json.NewDecoder(r.Body).Decode(&cmd) |
| 202 | if err != nil { |
| 203 | proxy.httpRespondErr(w, r, http.StatusBadRequest, err) |
| 204 | return |
| 205 | } |
| 206 | |
| 207 | ctx := r.Context() |
| 208 | data, err := proxy.client.Submit(ctx, &cmd) |
| 209 | |
| 210 | if err != nil { |
| 211 | proxy.httpRespondErr(w, r, http.StatusUnprocessableEntity, err) |
| 212 | return |
| 213 | } |
| 214 | |
| 215 | w.Header().Set("Content-type", "application/json") |
| 216 | err = json.NewEncoder(w).Encode(data) |
| 217 | if err != nil { |
| 218 | proxy.httpRespondErr(w, r, http.StatusInternalServerError, err) |
| 219 | } |
| 220 | } |
| 221 | } |
| 222 | |
| 223 | // httpRespond writes a status code and string response to the response writer. |
| 224 | func (proxy *Proxy) httpRespond(w http.ResponseWriter, r *http.Request, status int, message string) { |
| 225 | w.WriteHeader(status) |
| 226 | |
| 227 | // Only expose the message detail of the reponse if the request is not HEAD |
| 228 | // and the user is authenticated. For example, this prevents an unauthenticated |
| 229 | // failed health check from accidentally leaking sensitive information about the Client. |
| 230 | if r.Method != http.MethodHead && proxy.IsAllowed(r) { |
| 231 | if message == "" { |
| 232 | message = http.StatusText(status) |
| 233 | } |
| 234 | fmt.Fprint(w, message) |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | // httpRespondErr is similar to httpRespond, except it formats errors to be more friendly. |
| 239 | func (proxy *Proxy) httpRespondErr(w http.ResponseWriter, r *http.Request, defaultStatus int, err error) { |
| 240 | status, err := httpError(defaultStatus, err) |
| 241 | |
| 242 | proxy.httpRespond(w, r, status, err.Error()) |
| 243 | if len(err.Error()) > 0 { |
| 244 | cfRay := proxy.getRayHeader(r) |
| 245 | proxy.log.Err(err).Str(LogFieldCFRay, cfRay).Msg("dbproxy: Database proxy error") |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | // getRayHeader returns the request's Cf-ray header. |
| 250 | func (proxy *Proxy) getRayHeader(r *http.Request) string { |
| 251 | return r.Header.Get("Cf-ray") |
| 252 | } |
| 253 | |
| 254 | // httpError extracts common errors and returns an status code and friendly error. |
| 255 | func httpError(defaultStatus int, err error) (int, error) { |
| 256 | if err == nil { |
| 257 | return http.StatusNotImplemented, fmt.Errorf("error expected but found none") |
| 258 | } |
| 259 | |
| 260 | if err == io.EOF { |
| 261 | return http.StatusBadRequest, fmt.Errorf("request body cannot be empty") |
| 262 | } |
| 263 | |
| 264 | if err == context.DeadlineExceeded { |
| 265 | return http.StatusRequestTimeout, err |
| 266 | } |
| 267 | |
| 268 | _, ok := err.(net.Error) |
| 269 | if ok { |
| 270 | return http.StatusRequestTimeout, err |
| 271 | } |
| 272 | |
| 273 | if err == context.Canceled { |
| 274 | // Does not exist in Golang, but would be: http.StatusClientClosedWithoutResponse |
| 275 | return 444, err |
| 276 | } |
| 277 | |
| 278 | return defaultStatus, err |
| 279 | } |
| 280 | |