1 files changed, 60 insertions, 336 deletions

diff --git a/vendor/golang.org/x/net/http2/h2c/h2c.go b/vendor/golang.org/x/net/http2/h2c/h2c.go
index c0970d84..c3df711d 100644
--- a/vendor/golang.org/x/net/http2/h2c/h2c.go
+++ b/vendor/golang.org/x/net/http2/h2c/h2c.go
@@ -12,7 +12,6 @@ import (
 	"bufio"
 	"bytes"
 	"encoding/base64"
-	"encoding/binary"
 	"errors"
 	"fmt"
 	"io"
@@ -25,7 +24,6 @@ import (
 
 	"golang.org/x/net/http/httpguts"
 	"golang.org/x/net/http2"
-	"golang.org/x/net/http2/hpack"
 )
 
 var (
@@ -61,6 +59,10 @@ type h2cHandler struct {
 // Once a request is recognized as h2c, we hijack the connection and convert it
 // to an HTTP/2 connection which is understandable to s.ServeConn. (s.ServeConn
 // understands HTTP/2 except for the h2c part of it.)
+//
+// The first request on an h2c connection is read entirely into memory before
+// the Handler is called. To limit the memory consumed by this request, wrap
+// the result of NewHandler in an http.MaxBytesHandler.
 func NewHandler(h http.Handler, s *http2.Server) http.Handler {
 	return &h2cHandler{
 		Handler: h,
@@ -83,24 +85,31 @@ func (s h2cHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		defer conn.Close()
-
 		s.s.ServeConn(conn, &http2.ServeConnOpts{
-			Context: r.Context(),
-			Handler: s.Handler,
+			Context:          r.Context(),
+			Handler:          s.Handler,
+			SawClientPreface: true,
 		})
 		return
 	}
 	// Handle Upgrade to h2c (RFC 7540 Section 3.2)
-	if conn, err := h2cUpgrade(w, r); err == nil {
+	if isH2CUpgrade(r.Header) {
+		conn, settings, err := h2cUpgrade(w, r)
+		if err != nil {
+			if http2VerboseLogs {
+				log.Printf("h2c: error h2c upgrade: %v", err)
+			}
+			return
+		}
 		defer conn.Close()
-
 		s.s.ServeConn(conn, &http2.ServeConnOpts{
-			Context: r.Context(),
-			Handler: s.Handler,
+			Context:        r.Context(),
+			Handler:        s.Handler,
+			UpgradeRequest: r,
+			Settings:       settings,
 		})
 		return
 	}
-
 	s.Handler.ServeHTTP(w, r)
 	return
 }
@@ -113,11 +122,11 @@ func (s h2cHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 func initH2CWithPriorKnowledge(w http.ResponseWriter) (net.Conn, error) {
 	hijacker, ok := w.(http.Hijacker)
 	if !ok {
-		panic("Hijack not supported.")
+		return nil, errors.New("h2c: connection does not support Hijack")
 	}
 	conn, rw, err := hijacker.Hijack()
 	if err != nil {
-		panic(fmt.Sprintf("Hijack failed: %v", err))
+		return nil, err
 	}
 
 	const expectedBody = "SM\r\n\r\n"
@@ -125,249 +134,40 @@ func initH2CWithPriorKnowledge(w http.ResponseWriter) (net.Conn, error) {
 	buf := make([]byte, len(expectedBody))
 	n, err := io.ReadFull(rw, buf)
 	if err != nil {
-		return nil, fmt.Errorf("could not read from the buffer: %s", err)
+		return nil, fmt.Errorf("h2c: error reading client preface: %s", err)
 	}
 
 	if string(buf[:n]) == expectedBody {
-		c := &rwConn{
-			Conn:      conn,
-			Reader:    io.MultiReader(strings.NewReader(http2.ClientPreface), rw),
-			BufWriter: rw.Writer,
-		}
-		return c, nil
+		return newBufConn(conn, rw), nil
 	}
 
 	conn.Close()
-	if http2VerboseLogs {
-		log.Printf(
-			"h2c: missing the request body portion of the client preface. Wanted: %v Got: %v",
-			[]byte(expectedBody),
-			buf[0:n],
-		)
-	}
-	return nil, errors.New("invalid client preface")
-}
-
-// drainClientPreface reads a single instance of the HTTP/2 client preface from
-// the supplied reader.
-func drainClientPreface(r io.Reader) error {
-	var buf bytes.Buffer
-	prefaceLen := int64(len(http2.ClientPreface))
-	n, err := io.CopyN(&buf, r, prefaceLen)
-	if err != nil {
-		return err
-	}
-	if n != prefaceLen || buf.String() != http2.ClientPreface {
-		return fmt.Errorf("Client never sent: %s", http2.ClientPreface)
-	}
-	return nil
+	return nil, errors.New("h2c: invalid client preface")
 }
 
 // h2cUpgrade establishes a h2c connection using the HTTP/1 upgrade (Section 3.2).
-func h2cUpgrade(w http.ResponseWriter, r *http.Request) (net.Conn, error) {
-	if !isH2CUpgrade(r.Header) {
-		return nil, errors.New("non-conforming h2c headers")
-	}
-
-	// Initial bytes we put into conn to fool http2 server
-	initBytes, _, err := convertH1ReqToH2(r)
+func h2cUpgrade(w http.ResponseWriter, r *http.Request) (_ net.Conn, settings []byte, err error) {
+	settings, err = getH2Settings(r.Header)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
-
 	hijacker, ok := w.(http.Hijacker)
 	if !ok {
-		return nil, errors.New("hijack not supported.")
+		return nil, nil, errors.New("h2c: connection does not support Hijack")
 	}
+
+	body, _ := io.ReadAll(r.Body)
+	r.Body = io.NopCloser(bytes.NewBuffer(body))
+
 	conn, rw, err := hijacker.Hijack()
 	if err != nil {
-		return nil, fmt.Errorf("hijack failed: %v", err)
+		return nil, nil, err
 	}
 
 	rw.Write([]byte("HTTP/1.1 101 Switching Protocols\r\n" +
 		"Connection: Upgrade\r\n" +
 		"Upgrade: h2c\r\n\r\n"))
-	rw.Flush()
-
-	// A conforming client will now send an H2 client preface which need to drain
-	// since we already sent this.
-	if err := drainClientPreface(rw); err != nil {
-		return nil, err
-	}
-
-	c := &rwConn{
-		Conn:      conn,
-		Reader:    io.MultiReader(initBytes, rw),
-		BufWriter: newSettingsAckSwallowWriter(rw.Writer),
-	}
-	return c, nil
-}
-
-// convert the data contained in the HTTP/1 upgrade request into the HTTP/2
-// version in byte form.
-func convertH1ReqToH2(r *http.Request) (*bytes.Buffer, []http2.Setting, error) {
-	h2Bytes := bytes.NewBuffer([]byte((http2.ClientPreface)))
-	framer := http2.NewFramer(h2Bytes, nil)
-	settings, err := getH2Settings(r.Header)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	if err := framer.WriteSettings(settings...); err != nil {
-		return nil, nil, err
-	}
-
-	headerBytes, err := getH2HeaderBytes(r, getMaxHeaderTableSize(settings))
-	if err != nil {
-		return nil, nil, err
-	}
-
-	maxFrameSize := int(getMaxFrameSize(settings))
-	needOneHeader := len(headerBytes) < maxFrameSize
-	err = framer.WriteHeaders(http2.HeadersFrameParam{
-		StreamID:      1,
-		BlockFragment: headerBytes,
-		EndHeaders:    needOneHeader,
-	})
-	if err != nil {
-		return nil, nil, err
-	}
-
-	for i := maxFrameSize; i < len(headerBytes); i += maxFrameSize {
-		if len(headerBytes)-i > maxFrameSize {
-			if err := framer.WriteContinuation(1,
-				false, // endHeaders
-				headerBytes[i:maxFrameSize]); err != nil {
-				return nil, nil, err
-			}
-		} else {
-			if err := framer.WriteContinuation(1,
-				true, // endHeaders
-				headerBytes[i:]); err != nil {
-				return nil, nil, err
-			}
-		}
-	}
-
-	return h2Bytes, settings, nil
-}
-
-// getMaxFrameSize returns the SETTINGS_MAX_FRAME_SIZE. If not present default
-// value is 16384 as specified by RFC 7540 Section 6.5.2.
-func getMaxFrameSize(settings []http2.Setting) uint32 {
-	for _, setting := range settings {
-		if setting.ID == http2.SettingMaxFrameSize {
-			return setting.Val
-		}
-	}
-	return 16384
-}
-
-// getMaxHeaderTableSize returns the SETTINGS_HEADER_TABLE_SIZE. If not present
-// default value is 4096 as specified by RFC 7540 Section 6.5.2.
-func getMaxHeaderTableSize(settings []http2.Setting) uint32 {
-	for _, setting := range settings {
-		if setting.ID == http2.SettingHeaderTableSize {
-			return setting.Val
-		}
-	}
-	return 4096
-}
-
-// bufWriter is a Writer interface that also has a Flush method.
-type bufWriter interface {
-	io.Writer
-	Flush() error
-}
-
-// rwConn implements net.Conn but overrides Read and Write so that reads and
-// writes are forwarded to the provided io.Reader and bufWriter.
-type rwConn struct {
-	net.Conn
-	io.Reader
-	BufWriter bufWriter
-}
-
-// Read forwards reads to the underlying Reader.
-func (c *rwConn) Read(p []byte) (int, error) {
-	return c.Reader.Read(p)
-}
-
-// Write forwards writes to the underlying bufWriter and immediately flushes.
-func (c *rwConn) Write(p []byte) (int, error) {
-	n, err := c.BufWriter.Write(p)
-	if err := c.BufWriter.Flush(); err != nil {
-		return 0, err
-	}
-	return n, err
-}
-
-// settingsAckSwallowWriter is a writer that normally forwards bytes to its
-// underlying Writer, but swallows the first SettingsAck frame that it sees.
-type settingsAckSwallowWriter struct {
-	Writer     *bufio.Writer
-	buf        []byte
-	didSwallow bool
-}
-
-// newSettingsAckSwallowWriter returns a new settingsAckSwallowWriter.
-func newSettingsAckSwallowWriter(w *bufio.Writer) *settingsAckSwallowWriter {
-	return &settingsAckSwallowWriter{
-		Writer:     w,
-		buf:        make([]byte, 0),
-		didSwallow: false,
-	}
-}
-
-// Write implements io.Writer interface. Normally forwards bytes to w.Writer,
-// except for the first Settings ACK frame that it sees.
-func (w *settingsAckSwallowWriter) Write(p []byte) (int, error) {
-	if !w.didSwallow {
-		w.buf = append(w.buf, p...)
-		// Process all the frames we have collected into w.buf
-		for {
-			// Append until we get full frame header which is 9 bytes
-			if len(w.buf) < 9 {
-				break
-			}
-			// Check if we have collected a whole frame.
-			fh, err := http2.ReadFrameHeader(bytes.NewBuffer(w.buf))
-			if err != nil {
-				// Corrupted frame, fail current Write
-				return 0, err
-			}
-			fSize := fh.Length + 9
-			if uint32(len(w.buf)) < fSize {
-				// Have not collected whole frame. Stop processing buf, and withhold on
-				// forward bytes to w.Writer until we get the full frame.
-				break
-			}
-
-			// We have now collected a whole frame.
-			if fh.Type == http2.FrameSettings && fh.Flags.Has(http2.FlagSettingsAck) {
-				// If Settings ACK frame, do not forward to underlying writer, remove
-				// bytes from w.buf, and record that we have swallowed Settings Ack
-				// frame.
-				w.didSwallow = true
-				w.buf = w.buf[fSize:]
-				continue
-			}
-
-			// Not settings ack frame. Forward bytes to w.Writer.
-			if _, err := w.Writer.Write(w.buf[:fSize]); err != nil {
-				// Couldn't forward bytes. Fail current Write.
-				return 0, err
-			}
-			w.buf = w.buf[fSize:]
-		}
-		return len(p), nil
-	}
-	return w.Writer.Write(p)
-}
-
-// Flush calls w.Writer.Flush.
-func (w *settingsAckSwallowWriter) Flush() error {
-	return w.Writer.Flush()
+	return newBufConn(conn, rw), settings, nil
 }
 
 // isH2CUpgrade returns true if the header properly request an upgrade to h2c
@@ -377,9 +177,8 @@ func isH2CUpgrade(h http.Header) bool {
 		httpguts.HeaderValuesContainsToken(h[textproto.CanonicalMIMEHeaderKey("Connection")], "HTTP2-Settings")
 }
 
-// getH2Settings returns the []http2.Setting that are encoded in the
-// HTTP2-Settings header.
-func getH2Settings(h http.Header) ([]http2.Setting, error) {
+// getH2Settings returns the settings in the HTTP2-Settings header.
+func getH2Settings(h http.Header) ([]byte, error) {
 	vals, ok := h[textproto.CanonicalMIMEHeaderKey("HTTP2-Settings")]
 	if !ok {
 		return nil, errors.New("missing HTTP2-Settings header")
@@ -387,115 +186,40 @@ func getH2Settings(h http.Header) ([]http2.Setting, error) {
 	if len(vals) != 1 {
 		return nil, fmt.Errorf("expected 1 HTTP2-Settings. Got: %v", vals)
 	}
-	settings, err := decodeSettings(vals[0])
-	if err != nil {
-		return nil, fmt.Errorf("Invalid HTTP2-Settings: %q", vals[0])
-	}
-	return settings, nil
-}
-
-// decodeSettings decodes the base64url header value of the HTTP2-Settings
-// header. RFC 7540 Section 3.2.1.
-func decodeSettings(headerVal string) ([]http2.Setting, error) {
-	b, err := base64.RawURLEncoding.DecodeString(headerVal)
+	settings, err := base64.RawURLEncoding.DecodeString(vals[0])
 	if err != nil {
 		return nil, err
 	}
-	if len(b)%6 != 0 {
-		return nil, err
-	}
-	settings := make([]http2.Setting, 0)
-	for i := 0; i < len(b)/6; i++ {
-		settings = append(settings, http2.Setting{
-			ID:  http2.SettingID(binary.BigEndian.Uint16(b[i*6 : i*6+2])),
-			Val: binary.BigEndian.Uint32(b[i*6+2 : i*6+6]),
-		})
-	}
-
 	return settings, nil
 }
 
-// getH2HeaderBytes return the headers in r a []bytes encoded by HPACK.
-func getH2HeaderBytes(r *http.Request, maxHeaderTableSize uint32) ([]byte, error) {
-	headerBytes := bytes.NewBuffer(nil)
-	hpackEnc := hpack.NewEncoder(headerBytes)
-	hpackEnc.SetMaxDynamicTableSize(maxHeaderTableSize)
-
-	// Section 8.1.2.3
-	err := hpackEnc.WriteField(hpack.HeaderField{
-		Name:  ":method",
-		Value: r.Method,
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	err = hpackEnc.WriteField(hpack.HeaderField{
-		Name:  ":scheme",
-		Value: "http",
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	err = hpackEnc.WriteField(hpack.HeaderField{
-		Name:  ":authority",
-		Value: r.Host,
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	path := r.URL.Path
-	if r.URL.RawQuery != "" {
-		path = strings.Join([]string{path, r.URL.RawQuery}, "?")
-	}
-	err = hpackEnc.WriteField(hpack.HeaderField{
-		Name:  ":path",
-		Value: path,
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	// TODO Implement Section 8.3
-
-	for header, values := range r.Header {
-		// Skip non h2 headers
-		if isNonH2Header(header) {
-			continue
-		}
-		for _, v := range values {
-			err := hpackEnc.WriteField(hpack.HeaderField{
-				Name:  strings.ToLower(header),
-				Value: v,
-			})
-			if err != nil {
-				return nil, err
-			}
-		}
+func newBufConn(conn net.Conn, rw *bufio.ReadWriter) net.Conn {
+	rw.Flush()
+	if rw.Reader.Buffered() == 0 {
+		// If there's no buffered data to be read,
+		// we can just discard the bufio.ReadWriter.
+		return conn
 	}
-	return headerBytes.Bytes(), nil
+	return &bufConn{conn, rw.Reader}
 }
 
-// Connection specific headers listed in RFC 7540 Section 8.1.2.2 that are not
-// suppose to be transferred to HTTP/2. The Http2-Settings header is skipped
-// since already use to create the HTTP/2 SETTINGS frame.
-var nonH2Headers = []string{
-	"Connection",
-	"Keep-Alive",
-	"Proxy-Connection",
-	"Transfer-Encoding",
-	"Upgrade",
-	"Http2-Settings",
+// bufConn wraps a net.Conn, but reads drain the bufio.Reader first.
+type bufConn struct {
+	net.Conn
+	*bufio.Reader
 }
 
-// isNonH2Header returns true if header should not be transferred to HTTP/2.
-func isNonH2Header(header string) bool {
-	for _, nonH2h := range nonH2Headers {
-		if header == nonH2h {
-			return true
-		}
+func (c *bufConn) Read(p []byte) (int, error) {
+	if c.Reader == nil {
+		return c.Conn.Read(p)
+	}
+	n := c.Reader.Buffered()
+	if n == 0 {
+		c.Reader = nil
+		return c.Conn.Read(p)
 	}
-	return false
+	if n < len(p) {
+		p = p[:n]
+	}
+	return c.Reader.Read(p)
 }