Backport 1.9.x: Fixing ResponseWriter to assert to http.Flusher in /s…

…ys/monitor endpoint (#13200) (#13260)

* Unify HTTPResponseWriter and StatusHeaderResponseWriter (#13200)

* Unify NewHTTPResponseWriter ant NewStatusHeaderResponseWriter to fix ResponseWriter issues

* adding changelog

* removing unnecessary function from the WrappingResponseWriter interface

* changing logical requests responseWriter type

* reverting change to HTTPResponseWriter

* Update changelog/13200.txt

* Update changelog/13200.txt

changelog/13200.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+http:Fix /sys/monitor endpoint returning streaming not supported
+```

http/handler.go

@@ -17,14 +17,12 @@ import (
 	"net/url"
 	"os"
 	"regexp"
-	"strconv"
 	"strings"
 	"time"
 
 	"github.com/NYTimes/gziphandler"
 	"github.com/hashicorp/errwrap"
 	"github.com/hashicorp/go-cleanhttp"
-	log "github.com/hashicorp/go-hclog"
 	"github.com/hashicorp/go-secure-stdlib/parseutil"
 	"github.com/hashicorp/go-sockaddr"
 	"github.com/hashicorp/vault/helper/namespace"
@@ -215,89 +213,6 @@ func Handler(props *vault.HandlerProperties) http.Handler {
 	return printablePathCheckHandler
 }
 
-type WrappingResponseWriter interface {
-	http.ResponseWriter
-	Wrapped() http.ResponseWriter
-}
-
-type statusHeaderResponseWriter struct {
-	wrapped     http.ResponseWriter
-	logger      log.Logger
-	wroteHeader bool
-	statusCode  int
-	headers     map[string][]*vault.CustomHeader
-}
-
-func (w *statusHeaderResponseWriter) Wrapped() http.ResponseWriter {
-	return w.wrapped
-}
-
-func (w *statusHeaderResponseWriter) Header() http.Header {
-	return w.wrapped.Header()
-}
-
-func (w *statusHeaderResponseWriter) Write(buf []byte) (int, error) {
-	// It is allowed to only call ResponseWriter.Write and skip
-	// ResponseWriter.WriteHeader. An example of such a situation is
-	// "handleUIStub". The Write function will internally set the status code
-	// 200 for the response for which that call might invoke other
-	// implementations of the WriteHeader function. So, we still need to set
-	// the custom headers. In cases where both WriteHeader and Write of
-	// statusHeaderResponseWriter struct are called the internal call to the
-	// WriterHeader invoked from inside Write method won't change the headers.
-	if !w.wroteHeader {
-		w.setCustomResponseHeaders(w.statusCode)
-	}
-
-	return w.wrapped.Write(buf)
-}
-
-func (w *statusHeaderResponseWriter) WriteHeader(statusCode int) {
-	w.setCustomResponseHeaders(statusCode)
-	w.wrapped.WriteHeader(statusCode)
-	w.statusCode = statusCode
-	// in cases where Write is called after WriteHeader, let's prevent setting
-	// ResponseWriter headers twice
-	w.wroteHeader = true
-}
-
-func (w *statusHeaderResponseWriter) setCustomResponseHeaders(status int) {
-	sch := w.headers
-	if sch == nil {
-		w.logger.Warn("status code header map not configured")
-		return
-	}
-
-	// Checking the validity of the status code
-	if status >= 600 || status < 100 {
-		return
-	}
-
-	// setter function to set the headers
-	setter := func(hvl []*vault.CustomHeader) {
-		for _, hv := range hvl {
-			w.Header().Set(hv.Name, hv.Value)
-		}
-	}
-
-	// Setting the default headers first
-	setter(sch["default"])
-
-	// setting the Xyy pattern first
-	d := fmt.Sprintf("%vxx", status/100)
-	if val, ok := sch[d]; ok {
-		setter(val)
-	}
-
-	// Setting the specific headers
-	if val, ok := sch[strconv.Itoa(status)]; ok {
-		setter(val)
-	}
-
-	return
-}
-
-var _ WrappingResponseWriter = &statusHeaderResponseWriter{}
 
 type copyResponseWriter struct {
 	wrapped    http.ResponseWriter
@@ -389,25 +304,22 @@ func wrapGenericHandler(core *vault.Core, h http.Handler, props *vault.HandlerPr
 	hostname, _ := os.Hostname()
 
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+
 		// This block needs to be here so that upon sending SIGHUP, custom response
 		// headers are also reloaded into the handlers.
+		var customHeaders map[string][]*logical.CustomHeader
 		if props.ListenerConfig != nil {
 			la := props.ListenerConfig.Address
 			listenerCustomHeaders := core.GetListenerCustomResponseHeaders(la)
 			if listenerCustomHeaders != nil {
-				w = &statusHeaderResponseWriter{
-					wrapped:     w,
-					logger:      core.Logger(),
-					wroteHeader: false,
-					statusCode:  200,
-					headers:     listenerCustomHeaders.StatusCodeHeaderMap,
-				}
+				customHeaders = listenerCustomHeaders.StatusCodeHeaderMap
 			}
 		}
 
+		nw := logical.NewStatusHeaderResponseWriter(w, customHeaders)
 		// Set the Cache-Control header for all the responses returned
 		// by Vault
-		w.Header().Set("Cache-Control", "no-store")
+		nw.Header().Set("Cache-Control", "no-store")
 
 		// Start with the request context
 		ctx := r.Context()
@@ -431,38 +343,38 @@ func wrapGenericHandler(core *vault.Core, h http.Handler, props *vault.HandlerPr
 		if core.RaftNodeIDHeaderEnabled() {
 			nodeID := core.GetRaftNodeID()
 			if nodeID != "" {
-				w.Header().Set("X-Vault-Raft-Node-ID", nodeID)
+				nw.Header().Set("X-Vault-Raft-Node-ID", nodeID)
 			}
 		}
 
 		if core.HostnameHeaderEnabled() && hostname != "" {
-			w.Header().Set("X-Vault-Hostname", hostname)
+			nw.Header().Set("X-Vault-Hostname", hostname)
 		}
 
 		switch {
 		case strings.HasPrefix(r.URL.Path, "/v1/"):
 			newR, status := adjustRequest(core, r)
 			if status != 0 {
-				respondError(w, status, nil)
+				respondError(nw, status, nil)
 				cancelFunc()
 				return
 			}
 			r = newR
 
 		case strings.HasPrefix(r.URL.Path, "/ui"), r.URL.Path == "/robots.txt", r.URL.Path == "/":
 		default:
-			respondError(w, http.StatusNotFound, nil)
+			respondError(nw, http.StatusNotFound, nil)
 			cancelFunc()
 			return
 		}
 
 		// Setting the namespace in the header to be included in the error message
 		ns := r.Header.Get(consts.NamespaceHeaderName)
 		if ns != "" {
-			w.Header().Set(consts.NamespaceHeaderName, ns)
+			nw.Header().Set(consts.NamespaceHeaderName, ns)
 		}
 
-		h.ServeHTTP(w, r)
+		h.ServeHTTP(nw, r)
 
 		cancelFunc()
 		return
@@ -742,7 +654,7 @@ func parseJSONRequest(perfStandby bool, r *http.Request, w http.ResponseWriter,
 			// requestTooLarger.  So we let it have access to the underlying
 			// ResponseWriter.
 			inw := w
-			if myw, ok := inw.(WrappingResponseWriter); ok {
+			if myw, ok := inw.(logical.WrappingResponseWriter); ok {
 				inw = myw.Wrapped()
 			}
 			reader = http.MaxBytesReader(inw, r.Body, max)

sdk/logical/request.go

@@ -377,3 +377,8 @@ type InitializationRequest struct {
 	// Storage can be used to durably store and retrieve state.
 	Storage Storage
 }
+
+type CustomHeader struct {
+	Name  string
+	Value string
+}

sdk/logical/response.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"strconv"
 	"sync/atomic"
 
 	"github.com/hashicorp/vault/sdk/helper/wrapping"
@@ -209,13 +210,103 @@ func NewHTTPResponseWriter(w http.ResponseWriter) *HTTPResponseWriter {
 }
 
 // Write will write the bytes to the underlying io.Writer.
-func (rw *HTTPResponseWriter) Write(bytes []byte) (int, error) {
-	atomic.StoreUint32(rw.written, 1)
-
-	return rw.ResponseWriter.Write(bytes)
+func (w *HTTPResponseWriter) Write(bytes []byte) (int, error) {
+	atomic.StoreUint32(w.written, 1)
+	return w.ResponseWriter.Write(bytes)
 }
 
 // Written tells us if the writer has been written to yet.
-func (rw *HTTPResponseWriter) Written() bool {
-	return atomic.LoadUint32(rw.written) == 1
+func (w *HTTPResponseWriter) Written() bool {
+	return atomic.LoadUint32(w.written) == 1
+}
+
+type WrappingResponseWriter interface {
+	http.ResponseWriter
+	Wrapped() http.ResponseWriter
+}
+
+type StatusHeaderResponseWriter struct {
+	wrapped     http.ResponseWriter
+	wroteHeader bool
+	statusCode  int
+	headers     map[string][]*CustomHeader
+}
+
+func NewStatusHeaderResponseWriter(w http.ResponseWriter, h map[string][]*CustomHeader) *StatusHeaderResponseWriter {
+	return &StatusHeaderResponseWriter{
+		wrapped:     w,
+		wroteHeader: false,
+		statusCode:  200,
+		headers:     h,
+	}
+}
+
+func (w *StatusHeaderResponseWriter) Wrapped() http.ResponseWriter {
+	return w.wrapped
+}
+
+func (w *StatusHeaderResponseWriter) Header() http.Header {
+	return w.wrapped.Header()
+}
+
+func (w *StatusHeaderResponseWriter) Write(buf []byte) (int, error) {
+	// It is allowed to only call ResponseWriter.Write and skip
+	// ResponseWriter.WriteHeader. An example of such a situation is
+	// "handleUIStub". The Write function will internally set the status code
+	// 200 for the response for which that call might invoke other
+	// implementations of the WriteHeader function. So, we still need to set
+	// the custom headers. In cases where both WriteHeader and Write of
+	// statusHeaderResponseWriter struct are called the internal call to the
+	// WriterHeader invoked from inside Write method won't change the headers.
+	if !w.wroteHeader {
+		w.setCustomResponseHeaders(w.statusCode)
+	}
+
+	return w.wrapped.Write(buf)
 }
+
+func (w *StatusHeaderResponseWriter) WriteHeader(statusCode int) {
+	w.setCustomResponseHeaders(statusCode)
+	w.wrapped.WriteHeader(statusCode)
+	w.statusCode = statusCode
+	// in cases where Write is called after WriteHeader, let's prevent setting
+	// ResponseWriter headers twice
+	w.wroteHeader = true
+}
+
+func (w *StatusHeaderResponseWriter) setCustomResponseHeaders(status int) {
+	sch := w.headers
+	if sch == nil {
+		return
+	}
+
+	// Checking the validity of the status code
+	if status >= 600 || status < 100 {
+		return
+	}
+
+	// setter function to set the headers
+	setter := func(hvl []*CustomHeader) {
+		for _, hv := range hvl {
+			w.Header().Set(hv.Name, hv.Value)
+		}
+	}
+
+	// Setting the default headers first
+	setter(sch["default"])
+
+	// setting the Xyy pattern first
+	d := fmt.Sprintf("%vxx", status/100)
+	if val, ok := sch[d]; ok {
+		setter(val)
+	}
+
+	// Setting the specific headers
+	if val, ok := sch[strconv.Itoa(status)]; ok {
+		setter(val)
+	}
+
+	return
+}
+
+var _ WrappingResponseWriter = &StatusHeaderResponseWriter{}

vault/custom_response_headers.go

@@ -1,38 +1,35 @@
 package vault
 
 import (
+	"fmt"
 	"net/http"
 	"net/textproto"
 	"strings"
 
 	log "github.com/hashicorp/go-hclog"
 	"github.com/hashicorp/vault/internalshared/configutil"
+	"github.com/hashicorp/vault/sdk/logical"
 )
 
 type ListenerCustomHeaders struct {
 	Address             string
-	StatusCodeHeaderMap map[string][]*CustomHeader
+	StatusCodeHeaderMap map[string][]*logical.CustomHeader
 	// ConfiguredHeadersStatusCodeMap field is introduced so that we would not need to loop through
 	// StatusCodeHeaderMap to see if a header exists, the key for this map is the headers names
 	configuredHeadersStatusCodeMap map[string][]string
 }
 
-type CustomHeader struct {
-	Name  string
-	Value string
-}
-
 func NewListenerCustomHeader(ln []*configutil.Listener, logger log.Logger, uiHeaders http.Header) []*ListenerCustomHeaders {
 	var listenerCustomHeadersList []*ListenerCustomHeaders
 
 	for _, l := range ln {
 		listenerCustomHeaderStruct := &ListenerCustomHeaders{
 			Address: l.Address,
 		}
-		listenerCustomHeaderStruct.StatusCodeHeaderMap = make(map[string][]*CustomHeader)
+		listenerCustomHeaderStruct.StatusCodeHeaderMap = make(map[string][]*logical.CustomHeader)
 		listenerCustomHeaderStruct.configuredHeadersStatusCodeMap = make(map[string][]string)
 		for statusCode, headerValMap := range l.CustomResponseHeaders {
-			var customHeaderList []*CustomHeader
+			var customHeaderList []*logical.CustomHeader
 			for headerName, headerVal := range headerValMap {
 				// Sanitizing custom headers
 				// X-Vault- prefix is reserved for Vault internal processes
@@ -45,7 +42,7 @@ func NewListenerCustomHeader(ln []*configutil.Listener, logger log.Logger, uiHea
 				if uiHeaders != nil {
 					exist := uiHeaders.Get(headerName)
 					if exist != "" {
-						logger.Warn("found a duplicate header in UI", "header:", headerName, "Headers defined in the server configuration take precedence.")
+						logger.Warn(fmt.Sprintf("found a duplicate header in UI: header=%s. Headers defined in the server configuration take precedence.",  headerName))
 					}
 				}
 
@@ -55,7 +52,7 @@ func NewListenerCustomHeader(ln []*configutil.Listener, logger log.Logger, uiHea
 					continue
 				}
 
-				ch := &CustomHeader{
+				ch := &logical.CustomHeader{
 					Name:  headerName,
 					Value: headerVal,
 				}