// Copyright 2015 Matthew Holt and The Caddy Authors // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package caddyhttp import ( "context" "encoding/json" "fmt" "net" "net/http" "net/url" "runtime" "strings" "time" "github.com/caddyserver/caddy/v2" "github.com/caddyserver/caddy/v2/modules/caddytls" "github.com/lucas-clemente/quic-go/http3" "go.uber.org/zap" "go.uber.org/zap/zapcore" ) // Server describes an HTTP server. type Server struct { // Socket addresses to which to bind listeners. Accepts // [network addresses](/docs/conventions#network-addresses) // that may include port ranges. Listener addresses must // be unique; they cannot be repeated across all defined // servers. Listen []string `json:"listen,omitempty"` // A list of listener wrapper modules, which can modify the behavior // of the base listener. They are applied in the given order. ListenerWrappersRaw []json.RawMessage `json:"listener_wrappers,omitempty" caddy:"namespace=caddy.listeners inline_key=wrapper"` // How long to allow a read from a client's upload. Setting this // to a short, non-zero value can mitigate slowloris attacks, but // may also affect legitimately slow clients. ReadTimeout caddy.Duration `json:"read_timeout,omitempty"` // ReadHeaderTimeout is like ReadTimeout but for request headers. ReadHeaderTimeout caddy.Duration `json:"read_header_timeout,omitempty"` // WriteTimeout is how long to allow a write to a client. Note // that setting this to a small value when serving large files // may negatively affect legitimately slow clients. WriteTimeout caddy.Duration `json:"write_timeout,omitempty"` // IdleTimeout is the maximum time to wait for the next request // when keep-alives are enabled. If zero, a default timeout of // 5m is applied to help avoid resource exhaustion. IdleTimeout caddy.Duration `json:"idle_timeout,omitempty"` // MaxHeaderBytes is the maximum size to parse from a client's // HTTP request headers. MaxHeaderBytes int `json:"max_header_bytes,omitempty"` // Routes describes how this server will handle requests. // Routes are executed sequentially. First a route's matchers // are evaluated, then its grouping. If it matches and has // not been mutually-excluded by its grouping, then its // handlers are executed sequentially. The sequence of invoked // handlers comprises a compiled middleware chain that flows // from each matching route and its handlers to the next. // // By default, all unrouted requests receive a 200 OK response // to indicate the server is working. Routes RouteList `json:"routes,omitempty"` // Errors is how this server will handle errors returned from any // of the handlers in the primary routes. If the primary handler // chain returns an error, the error along with its recommended // status code are bubbled back up to the HTTP server which // executes a separate error route, specified using this property. // The error routes work exactly like the normal routes. Errors *HTTPErrorConfig `json:"errors,omitempty"` // How to handle TLS connections. At least one policy is // required to enable HTTPS on this server if automatic // HTTPS is disabled or does not apply. TLSConnPolicies caddytls.ConnectionPolicies `json:"tls_connection_policies,omitempty"` // AutoHTTPS configures or disables automatic HTTPS within this server. // HTTPS is enabled automatically and by default when qualifying names // are present in a Host matcher and/or when the server is listening // only on the HTTPS port. AutoHTTPS *AutoHTTPSConfig `json:"automatic_https,omitempty"` // If true, will require that a request's Host header match // the value of the ServerName sent by the client's TLS // ClientHello; often a necessary safeguard when using TLS // client authentication. StrictSNIHost *bool `json:"strict_sni_host,omitempty"` // Enables access logging and configures how access logs are handled // in this server. To minimally enable access logs, simply set this // to a non-null, empty struct. Logs *ServerLogConfig `json:"logs,omitempty"` // Enable experimental HTTP/3 support. Note that HTTP/3 is not a // finished standard and has extremely limited client support. // This field is not subject to compatibility promises. ExperimentalHTTP3 bool `json:"experimental_http3,omitempty"` // Enables H2C ("Cleartext HTTP/2" or "H2 over TCP") support, // which will serve HTTP/2 over plaintext TCP connections if // the client supports it. Because this is not implemented by the // Go standard library, using H2C is incompatible with most // of the other options for this server. Do not enable this // only to achieve maximum client compatibility. In practice, // very few clients implement H2C, and even fewer require it. // This setting applies only to unencrypted HTTP listeners. // ⚠️ Experimental feature; subject to change or removal. AllowH2C bool `json:"allow_h2c,omitempty"` name string primaryHandlerChain Handler errorHandlerChain Handler listenerWrappers []caddy.ListenerWrapper tlsApp *caddytls.TLS logger *zap.Logger accessLogger *zap.Logger errorLogger *zap.Logger h3server *http3.Server } // ServeHTTP is the entry point for all HTTP requests. func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) { w.Header().Set("Server", "Caddy") if s.h3server != nil { err := s.h3server.SetQuicHeaders(w.Header()) if err != nil { s.logger.Error("setting HTTP/3 Alt-Svc header", zap.Error(err)) } } repl := caddy.NewReplacer() r = PrepareRequest(r, repl, w, s) // encode the request for logging purposes before // it enters any handler chain; this is necessary // to capture the original request in case it gets // modified during handling loggableReq := zap.Object("request", LoggableHTTPRequest{r}) errLog := s.errorLogger.With(loggableReq) var duration time.Duration if s.shouldLogRequest(r) { wrec := NewResponseRecorder(w, nil, nil) w = wrec // capture the original version of the request accLog := s.accessLogger.With(loggableReq) defer func() { repl.Set("http.response.status", wrec.Status()) repl.Set("http.response.size", wrec.Size()) repl.Set("http.response.duration", duration) logger := accLog if s.Logs != nil { logger = s.Logs.wrapLogger(logger, r.Host) } log := logger.Info if wrec.Status() >= 400 { log = logger.Error } log("handled request", zap.String("common_log", repl.ReplaceAll(commonLogFormat, commonLogEmptyValue)), zap.Duration("duration", duration), zap.Int("size", wrec.Size()), zap.Int("status", wrec.Status()), zap.Object("resp_headers", LoggableHTTPHeader(wrec.Header())), ) }() } start := time.Now() // guarantee ACME HTTP challenges; handle them // separately from any user-defined handlers if s.tlsApp.HandleHTTPChallenge(w, r) { duration = time.Since(start) return } // execute the primary handler chain err := s.primaryHandlerChain.ServeHTTP(w, r) duration = time.Since(start) // if no errors, we're done! if err == nil { return } // restore original request before invoking error handler chain (issue #3717) // TODO: this does not restore original headers, if modified (for efficiency) origReq := r.Context().Value(OriginalRequestCtxKey).(http.Request) r.Method = origReq.Method r.RemoteAddr = origReq.RemoteAddr r.RequestURI = origReq.RequestURI cloneURL(origReq.URL, r.URL) // prepare the error log logger := errLog if s.Logs != nil { logger = s.Logs.wrapLogger(logger, r.Host) } logger = logger.With(zap.Duration("duration", duration)) // get the values that will be used to log the error errStatus, errMsg, errFields := errLogValues(err) // add HTTP error information to request context r = s.Errors.WithError(r, err) if s.Errors != nil && len(s.Errors.Routes) > 0 { // execute user-defined error handling route err2 := s.errorHandlerChain.ServeHTTP(w, r) if err2 == nil { // user's error route handled the error response // successfully, so now just log the error if errStatus >= 500 { logger.Error(errMsg, errFields...) } } else { // well... this is awkward errFields = append([]zapcore.Field{ zap.String("error", err2.Error()), zap.Namespace("first_error"), zap.String("msg", errMsg), }, errFields...) logger.Error("error handling handler error", errFields...) if handlerErr, ok := err.(HandlerError); ok { w.WriteHeader(handlerErr.StatusCode) } else { w.WriteHeader(http.StatusInternalServerError) } } } else { if errStatus >= 500 { logger.Error(errMsg, errFields...) } w.WriteHeader(errStatus) } } // wrapPrimaryRoute wraps stack (a compiled middleware handler chain) // in s.enforcementHandler which performs crucial security checks, etc. func (s *Server) wrapPrimaryRoute(stack Handler) Handler { return HandlerFunc(func(w http.ResponseWriter, r *http.Request) error { return s.enforcementHandler(w, r, stack) }) } // enforcementHandler is an implicit middleware which performs // standard checks before executing the HTTP middleware chain. func (s *Server) enforcementHandler(w http.ResponseWriter, r *http.Request, next Handler) error { // enforce strict host matching, which ensures that the SNI // value (if any), matches the Host header; essential for // servers that rely on TLS ClientAuth sharing a listener // with servers that do not; if not enforced, client could // bypass by sending benign SNI then restricted Host header if s.StrictSNIHost != nil && *s.StrictSNIHost && r.TLS != nil { hostname, _, err := net.SplitHostPort(r.Host) if err != nil { hostname = r.Host // OK; probably lacked port } if !strings.EqualFold(r.TLS.ServerName, hostname) { err := fmt.Errorf("strict host matching: TLS ServerName (%s) and HTTP Host (%s) values differ", r.TLS.ServerName, hostname) r.Close = true return Error(http.StatusForbidden, err) } } return next.ServeHTTP(w, r) } // listenersUseAnyPortOtherThan returns true if there are any // listeners in s that use a port which is not otherPort. func (s *Server) listenersUseAnyPortOtherThan(otherPort int) bool { for _, lnAddr := range s.Listen { laddrs, err := caddy.ParseNetworkAddress(lnAddr) if err != nil { continue } if uint(otherPort) > laddrs.EndPort || uint(otherPort) < laddrs.StartPort { return true } } return false } // hasListenerAddress returns true if s has a listener // at the given address fullAddr. Currently, fullAddr // must represent exactly one socket address (port // ranges are not supported) func (s *Server) hasListenerAddress(fullAddr string) bool { laddrs, err := caddy.ParseNetworkAddress(fullAddr) if err != nil { return false } if laddrs.PortRangeSize() != 1 { return false // TODO: support port ranges } for _, lnAddr := range s.Listen { thisAddrs, err := caddy.ParseNetworkAddress(lnAddr) if err != nil { continue } if thisAddrs.Network != laddrs.Network { continue } // Apparently, Linux requires all bound ports to be distinct // *regardless of host interface* even if the addresses are // in fact different; binding "192.168.0.1:9000" and then // ":9000" will fail for ":9000" because "address is already // in use" even though it's not, and the same bindings work // fine on macOS. I also found on Linux that listening on // "[::]:9000" would fail with a similar error, except with // the address "0.0.0.0:9000", as if deliberately ignoring // that I specified the IPv6 interface explicitly. This seems // to be a major bug in the Linux network stack and I don't // know why it hasn't been fixed yet, so for now we have to // special-case ourselves around Linux like a doting parent. // The second issue seems very similar to a discussion here: // https://github.com/nodejs/node/issues/9390 // // This is very easy to reproduce by creating an HTTP server // that listens to both addresses or just one with a host // interface; or for a more confusing reproduction, try // listening on "127.0.0.1:80" and ":443" and you'll see // the error, if you take away the GOOS condition below. // // So, an address is equivalent if the port is in the port // range, and if not on Linux, the host is the same... sigh. if (runtime.GOOS == "linux" || thisAddrs.Host == laddrs.Host) && (laddrs.StartPort <= thisAddrs.EndPort) && (laddrs.StartPort >= thisAddrs.StartPort) { return true } } return false } func (s *Server) hasTLSClientAuth() bool { for _, cp := range s.TLSConnPolicies { if cp.ClientAuthentication != nil && cp.ClientAuthentication.Active() { return true } } return false } // HTTPErrorConfig determines how to handle errors // from the HTTP handlers. type HTTPErrorConfig struct { // The routes to evaluate after the primary handler // chain returns an error. In an error route, extra // placeholders are available: // // Placeholder | Description // ------------|--------------- // `{http.error.status_code}` | The recommended HTTP status code // `{http.error.status_text}` | The status text associated with the recommended status code // `{http.error.message}` | The error message // `{http.error.trace}` | The origin of the error // `{http.error.id}` | An identifier for this occurrence of the error Routes RouteList `json:"routes,omitempty"` } // WithError makes a shallow copy of r to add the error to its // context, and sets placeholders on the request's replacer // related to err. It returns the modified request which has // the error information in its context and replacer. It // overwrites any existing error values that are stored. func (*HTTPErrorConfig) WithError(r *http.Request, err error) *http.Request { // add the raw error value to the request context // so it can be accessed by error handlers c := context.WithValue(r.Context(), ErrorCtxKey, err) r = r.WithContext(c) // add error values to the replacer repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer) repl.Set("http.error", err) if handlerErr, ok := err.(HandlerError); ok { repl.Set("http.error.status_code", handlerErr.StatusCode) repl.Set("http.error.status_text", http.StatusText(handlerErr.StatusCode)) repl.Set("http.error.trace", handlerErr.Trace) repl.Set("http.error.id", handlerErr.ID) } return r } // shouldLogRequest returns true if this request should be logged. func (s *Server) shouldLogRequest(r *http.Request) bool { if s.accessLogger == nil || s.Logs == nil { // logging is disabled return false } for _, dh := range s.Logs.SkipHosts { // logging for this particular host is disabled if r.Host == dh { return false } } if _, ok := s.Logs.LoggerNames[r.Host]; ok { // this host is mapped to a particular logger name return true } if s.Logs.SkipUnmappedHosts { // this host is not mapped and thus must not be logged return false } return true } // ServerLogConfig describes a server's logging configuration. If // enabled without customization, all requests to this server are // logged to the default logger; logger destinations may be // customized per-request-host. type ServerLogConfig struct { // The default logger name for all logs emitted by this server for // hostnames that are not in the LoggerNames (logger_names) map. DefaultLoggerName string `json:"default_logger_name,omitempty"` // LoggerNames maps request hostnames to a custom logger name. // For example, a mapping of "example.com" to "example" would // cause access logs from requests with a Host of example.com // to be emitted by a logger named "http.log.access.example". LoggerNames map[string]string `json:"logger_names,omitempty"` // By default, all requests to this server will be logged if // access logging is enabled. This field lists the request // hosts for which access logging should be disabled. SkipHosts []string `json:"skip_hosts,omitempty"` // If true, requests to any host not appearing in the // LoggerNames (logger_names) map will not be logged. SkipUnmappedHosts bool `json:"skip_unmapped_hosts,omitempty"` } // wrapLogger wraps logger in a logger named according to user preferences for the given host. func (slc ServerLogConfig) wrapLogger(logger *zap.Logger, host string) *zap.Logger { if loggerName := slc.getLoggerName(host); loggerName != "" { return logger.Named(loggerName) } return logger } func (slc ServerLogConfig) getLoggerName(host string) string { tryHost := func(key string) (string, bool) { // first try exact match if loggerName, ok := slc.LoggerNames[key]; ok { return loggerName, ok } // strip port and try again (i.e. Host header of "example.com:1234" should // match "example.com" if there is no "example.com:1234" in the map) hostOnly, _, err := net.SplitHostPort(key) if err != nil { return "", false } loggerName, ok := slc.LoggerNames[hostOnly] return loggerName, ok } // try the exact hostname first if loggerName, ok := tryHost(host); ok { return loggerName } // try matching wildcard domains if other non-specific loggers exist labels := strings.Split(host, ".") for i := range labels { if labels[i] == "" { continue } labels[i] = "*" wildcardHost := strings.Join(labels, ".") if loggerName, ok := tryHost(wildcardHost); ok { return loggerName } } return slc.DefaultLoggerName } // PrepareRequest fills the request r for use in a Caddy HTTP handler chain. w and s can // be nil, but the handlers will lose response placeholders and access to the server. func PrepareRequest(r *http.Request, repl *caddy.Replacer, w http.ResponseWriter, s *Server) *http.Request { // set up the context for the request ctx := context.WithValue(r.Context(), caddy.ReplacerCtxKey, repl) ctx = context.WithValue(ctx, ServerCtxKey, s) ctx = context.WithValue(ctx, VarsCtxKey, make(map[string]interface{})) ctx = context.WithValue(ctx, routeGroupCtxKey, make(map[string]struct{})) var url2 url.URL // avoid letting this escape to the heap ctx = context.WithValue(ctx, OriginalRequestCtxKey, originalRequest(r, &url2)) r = r.WithContext(ctx) // once the pointer to the request won't change // anymore, finish setting up the replacer addHTTPVarsToReplacer(repl, r, w) return r } // errLogValues inspects err and returns the status code // to use, the error log message, and any extra fields. // If err is a HandlerError, the returned values will // have richer information. func errLogValues(err error) (status int, msg string, fields []zapcore.Field) { if handlerErr, ok := err.(HandlerError); ok { status = handlerErr.StatusCode if handlerErr.Err == nil { msg = err.Error() } else { msg = handlerErr.Err.Error() } fields = []zapcore.Field{ zap.Int("status", handlerErr.StatusCode), zap.String("err_id", handlerErr.ID), zap.String("err_trace", handlerErr.Trace), } return } status = http.StatusInternalServerError msg = err.Error() return } // originalRequest returns a partial, shallow copy of // req, including: req.Method, deep copy of req.URL // (into the urlCopy parameter, which should be on the // stack), req.RequestURI, and req.RemoteAddr. Notably, // headers are not copied. This function is designed to // be very fast and efficient, and useful primarily for // read-only/logging purposes. func originalRequest(req *http.Request, urlCopy *url.URL) http.Request { cloneURL(req.URL, urlCopy) return http.Request{ Method: req.Method, RemoteAddr: req.RemoteAddr, RequestURI: req.RequestURI, URL: urlCopy, } } // cloneURL makes a copy of r.URL and returns a // new value that doesn't reference the original. func cloneURL(from, to *url.URL) { *to = *from if from.User != nil { userInfo := new(url.Userinfo) *userInfo = *from.User to.User = userInfo } } const ( // commonLogFormat is the common log format. https://en.wikipedia.org/wiki/Common_Log_Format commonLogFormat = `{http.request.remote.host} ` + commonLogEmptyValue + ` {http.auth.user.id} [{time.now.common_log}] "{http.request.orig_method} {http.request.orig_uri} {http.request.proto}" {http.response.status} {http.response.size}` // commonLogEmptyValue is the common empty log value. commonLogEmptyValue = "-" ) // Context keys for HTTP request context values. const ( // For referencing the server instance ServerCtxKey caddy.CtxKey = "server" // For the request's variable table VarsCtxKey caddy.CtxKey = "vars" // For a partial copy of the unmodified request that // originally came into the server's entry handler OriginalRequestCtxKey caddy.CtxKey = "original_request" )