net/http: update bundled http2

Updates x/net/http2 to git rev 5916dcb1 for:

* http2, lex/httplex: make Transport reject bogus headers before sending
  https://golang.org/cl/23229

* http2: reject more trailer values
  https://golang.org/cl/23230

Fixes #14048
Fixes #14188

Change-Id: Iaa8beca6e005267a3e849a10013eb424a882f2bb
Reviewed-on: https://go-review.googlesource.com/23234
Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

7 files changed, 99 insertions, 521 deletions

diff --git a/src/net/http/h2_bundle.go b/src/net/http/h2_bundle.go
index 22047c5826..6f7fd382ea 100644
--- a/src/net/http/h2_bundle.go
+++ b/src/net/http/h2_bundle.go
@@ -26,6 +26,7 @@ import (
 	"errors"
 	"fmt"
 	"golang.org/x/net/http2/hpack"
+	"golang.org/x/net/lex/httplex"
 	"io"
 	"io/ioutil"
 	"log"
@@ -1864,7 +1865,7 @@ func (fr *http2Framer) readMetaFrame(hf *http2HeadersFrame) (*http2MetaHeadersFr
 	hdec.SetEmitEnabled(true)
 	hdec.SetMaxStringLength(fr.maxHeaderStringLen())
 	hdec.SetEmitFunc(func(hf hpack.HeaderField) {
-		if !http2validHeaderFieldValue(hf.Value) {
+		if !httplex.ValidHeaderFieldValue(hf.Value) {
 			invalid = http2headerFieldValueError(hf.Value)
 		}
 		isPseudo := strings.HasPrefix(hf.Name, ":")
@@ -1874,7 +1875,7 @@ func (fr *http2Framer) readMetaFrame(hf *http2HeadersFrame) (*http2MetaHeadersFr
 			}
 		} else {
 			sawRegular = true
-			if !http2validHeaderFieldName(hf.Name) {
+			if !http2validWireHeaderFieldName(hf.Name) {
 				invalid = http2headerFieldNameError(hf.Name)
 			}
 		}
@@ -2397,58 +2398,23 @@ var (
 	http2errInvalidHeaderFieldValue = errors.New("http2: invalid header field value")
 )
 
-// validHeaderFieldName reports whether v is a valid header field name (key).
-//  RFC 7230 says:
-//   header-field   = field-name ":" OWS field-value OWS
-//   field-name     = token
-//   token          = 1*tchar
-//   tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." /
-//           "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA
+// validWireHeaderFieldName reports whether v is a valid header field
+// name (key). See httplex.ValidHeaderName for the base rules.
+//
 // Further, http2 says:
 //   "Just as in HTTP/1.x, header field names are strings of ASCII
 //   characters that are compared in a case-insensitive
 //   fashion. However, header field names MUST be converted to
 //   lowercase prior to their encoding in HTTP/2. "
-func http2validHeaderFieldName(v string) bool {
+func http2validWireHeaderFieldName(v string) bool {
 	if len(v) == 0 {
 		return false
 	}
 	for _, r := range v {
-		if int(r) >= len(http2isTokenTable) || ('A' <= r && r <= 'Z') {
+		if !httplex.IsTokenRune(r) {
 			return false
 		}
-		if !http2isTokenTable[byte(r)] {
-			return false
-		}
-	}
-	return true
-}
-
-// validHeaderFieldValue reports whether v is a valid header field value.
-//
-// RFC 7230 says:
-//  field-value    = *( field-content / obs-fold )
-//  obj-fold       =  N/A to http2, and deprecated
-//  field-content  = field-vchar [ 1*( SP / HTAB ) field-vchar ]
-//  field-vchar    = VCHAR / obs-text
-//  obs-text       = %x80-FF
-//  VCHAR          = "any visible [USASCII] character"
-//
-// http2 further says: "Similarly, HTTP/2 allows header field values
-// that are not valid. While most of the values that can be encoded
-// will not alter header field parsing, carriage return (CR, ASCII
-// 0xd), line feed (LF, ASCII 0xa), and the zero character (NUL, ASCII
-// 0x0) might be exploited by an attacker if they are translated
-// verbatim. Any request or response that contains a character not
-// permitted in a header field value MUST be treated as malformed
-// (Section 8.1.2.6). Valid characters are defined by the
-// field-content ABNF rule in Section 3.2 of [RFC7230]."
-//
-// This function does not (yet?) properly handle the rejection of
-// strings that begin or end with SP or HTAB.
-func http2validHeaderFieldValue(v string) bool {
-	for i := 0; i < len(v); i++ {
-		if b := v[i]; b < ' ' && b != '\t' || b == 0x7f {
+		if 'A' <= r && r <= 'Z' {
 			return false
 		}
 	}
@@ -2579,86 +2545,6 @@ func (e *http2httpError) Temporary() bool { return true }
 
 var http2errTimeout error = &http2httpError{msg: "http2: timeout awaiting response headers", timeout: true}
 
-var http2isTokenTable = [127]bool{
-	'!':  true,
-	'#':  true,
-	'$':  true,
-	'%':  true,
-	'&':  true,
-	'\'': true,
-	'*':  true,
-	'+':  true,
-	'-':  true,
-	'.':  true,
-	'0':  true,
-	'1':  true,
-	'2':  true,
-	'3':  true,
-	'4':  true,
-	'5':  true,
-	'6':  true,
-	'7':  true,
-	'8':  true,
-	'9':  true,
-	'A':  true,
-	'B':  true,
-	'C':  true,
-	'D':  true,
-	'E':  true,
-	'F':  true,
-	'G':  true,
-	'H':  true,
-	'I':  true,
-	'J':  true,
-	'K':  true,
-	'L':  true,
-	'M':  true,
-	'N':  true,
-	'O':  true,
-	'P':  true,
-	'Q':  true,
-	'R':  true,
-	'S':  true,
-	'T':  true,
-	'U':  true,
-	'W':  true,
-	'V':  true,
-	'X':  true,
-	'Y':  true,
-	'Z':  true,
-	'^':  true,
-	'_':  true,
-	'`':  true,
-	'a':  true,
-	'b':  true,
-	'c':  true,
-	'd':  true,
-	'e':  true,
-	'f':  true,
-	'g':  true,
-	'h':  true,
-	'i':  true,
-	'j':  true,
-	'k':  true,
-	'l':  true,
-	'm':  true,
-	'n':  true,
-	'o':  true,
-	'p':  true,
-	'q':  true,
-	'r':  true,
-	's':  true,
-	't':  true,
-	'u':  true,
-	'v':  true,
-	'w':  true,
-	'x':  true,
-	'y':  true,
-	'z':  true,
-	'|':  true,
-	'~':  true,
-}
-
 type http2connectionStater interface {
 	ConnectionState() tls.ConnectionState
 }
@@ -4103,6 +3989,10 @@ func (st *http2stream) processTrailerHeaders(f *http2MetaHeadersFrame) error {
 	if st.trailer != nil {
 		for _, hf := range f.RegularFields() {
 			key := sc.canonicalHeader(hf.Name)
+			if !http2ValidTrailerHeader(key) {
+
+				return http2StreamError{st.id, http2ErrCodeProtocol}
+			}
 			st.trailer[key] = append(st.trailer[key], hf.Value)
 		}
 	}
@@ -4508,9 +4398,9 @@ func (rws *http2responseWriterState) hasTrailers() bool { return len(rws.trailer
 // written in the trailers at the end of the response.
 func (rws *http2responseWriterState) declareTrailer(k string) {
 	k = CanonicalHeaderKey(k)
-	switch k {
-	case "Transfer-Encoding", "Content-Length", "Trailer":
+	if !http2ValidTrailerHeader(k) {
 
+		rws.conn.logf("ignoring invalid trailer %q", k)
 		return
 	}
 	if !http2strSliceContains(rws.trailers, k) {
@@ -4831,6 +4721,41 @@ func http2new400Handler(err error) HandlerFunc {
 	}
 }
 
+// ValidTrailerHeader reports whether name is a valid header field name to appear
+// in trailers.
+// See: http://tools.ietf.org/html/rfc7230#section-4.1.2
+func http2ValidTrailerHeader(name string) bool {
+	name = CanonicalHeaderKey(name)
+	if strings.HasPrefix(name, "If-") || http2badTrailer[name] {
+		return false
+	}
+	return true
+}
+
+var http2badTrailer = map[string]bool{
+	"Authorization":       true,
+	"Cache-Control":       true,
+	"Connection":          true,
+	"Content-Encoding":    true,
+	"Content-Length":      true,
+	"Content-Range":       true,
+	"Content-Type":        true,
+	"Expect":              true,
+	"Host":                true,
+	"Keep-Alive":          true,
+	"Max-Forwards":        true,
+	"Pragma":              true,
+	"Proxy-Authenticate":  true,
+	"Proxy-Authorization": true,
+	"Proxy-Connection":    true,
+	"Range":               true,
+	"Realm":               true,
+	"Te":                  true,
+	"Trailer":             true,
+	"Transfer-Encoding":   true,
+	"Www-Authenticate":    true,
+}
+
 const (
 	// transportDefaultConnFlow is how many connection-level flow control
 	// tokens we give the server at start-up, past the default 64k.
@@ -5423,20 +5348,28 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 		return nil, http2errClientConnUnusable
 	}
 
-	cs := cc.newStream()
-	cs.req = req
-	cs.trace = http2requestTrace(req)
-	hasBody := body != nil
-
+	// TODO(bradfitz): this is a copy of the logic in net/http. Unify somewhere?
+	var requestedGzip bool
 	if !cc.t.disableCompression() &&
 		req.Header.Get("Accept-Encoding") == "" &&
 		req.Header.Get("Range") == "" &&
 		req.Method != "HEAD" {
 
-		cs.requestedGzip = true
+		requestedGzip = true
 	}
 
-	hdrs := cc.encodeHeaders(req, cs.requestedGzip, trailers, contentLen)
+	hdrs, err := cc.encodeHeaders(req, requestedGzip, trailers, contentLen)
+	if err != nil {
+		cc.mu.Unlock()
+		return nil, err
+	}
+
+	cs := cc.newStream()
+	cs.req = req
+	cs.trace = http2requestTrace(req)
+	hasBody := body != nil
+	cs.requestedGzip = requestedGzip
+
 	cc.wmu.Lock()
 	endStream := !hasBody && !hasTrailers
 	werr := cc.writeHeaders(cs.ID, endStream, hdrs)
@@ -5689,7 +5622,7 @@ type http2badStringError struct {
 func (e *http2badStringError) Error() string { return fmt.Sprintf("%s %q", e.what, e.str) }
 
 // requires cc.mu be held.
-func (cc *http2ClientConn) encodeHeaders(req *Request, addGzipHeader bool, trailers string, contentLength int64) []byte {
+func (cc *http2ClientConn) encodeHeaders(req *Request, addGzipHeader bool, trailers string, contentLength int64) ([]byte, error) {
 	cc.hbuf.Reset()
 
 	host := req.Host
@@ -5697,6 +5630,17 @@ func (cc *http2ClientConn) encodeHeaders(req *Request, addGzipHeader bool, trail
 		host = req.URL.Host
 	}
 
+	for k, vv := range req.Header {
+		if !httplex.ValidHeaderFieldName(k) {
+			return nil, fmt.Errorf("invalid HTTP header name %q", k)
+		}
+		for _, v := range vv {
+			if !httplex.ValidHeaderFieldValue(v) {
+				return nil, fmt.Errorf("invalid HTTP header value %q for header %q", v, k)
+			}
+		}
+	}
+
 	cc.writeHeader(":authority", host)
 	cc.writeHeader(":method", req.Method)
 	if req.Method != "CONNECT" {
@@ -5741,7 +5685,7 @@ func (cc *http2ClientConn) encodeHeaders(req *Request, addGzipHeader bool, trail
 	if !didUA {
 		cc.writeHeader("user-agent", http2defaultUserAgent)
 	}
-	return cc.hbuf.Bytes()
+	return cc.hbuf.Bytes(), nil
 }
 
 // shouldSendReqContentLength reports whether the http2.Transport should send
@@ -6622,13 +6566,13 @@ func http2encodeHeaders(enc *hpack.Encoder, h Header, keys []string) {
 	for _, k := range keys {
 		vv := h[k]
 		k = http2lowerHeader(k)
-		if !http2validHeaderFieldName(k) {
+		if !http2validWireHeaderFieldName(k) {
 
 			continue
 		}
 		isTE := k == "transfer-encoding"
 		for _, v := range vv {
-			if !http2validHeaderFieldValue(v) {
+			if !httplex.ValidHeaderFieldValue(v) {
 
 				continue
 			}
diff --git a/src/net/http/http.go b/src/net/http/http.go
index a121628632..4d088a5bb1 100644
--- a/src/net/http/http.go
+++ b/src/net/http/http.go
@@ -6,6 +6,8 @@ package http
 
 import (
 	"strings"
+
+	"golang.org/x/net/lex/httplex"
 )
 
 // maxInt64 is the effective "infinite" value for the Server and
@@ -35,3 +37,7 @@ func removeEmptyPort(host string) string {
 	}
 	return host
 }
+
+func isNotToken(r rune) bool {
+	return !httplex.IsTokenRune(r)
+}
diff --git a/src/net/http/lex.go b/src/net/http/lex.go
deleted file mode 100644
index 63d14ec2ec..0000000000
--- a/src/net/http/lex.go
+++ /dev/null
@@ -1,277 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package http
-
-import (
-	"strings"
-	"unicode/utf8"
-)
-
-// This file deals with lexical matters of HTTP
-
-var isTokenTable = [127]bool{
-	'!':  true,
-	'#':  true,
-	'$':  true,
-	'%':  true,
-	'&':  true,
-	'\'': true,
-	'*':  true,
-	'+':  true,
-	'-':  true,
-	'.':  true,
-	'0':  true,
-	'1':  true,
-	'2':  true,
-	'3':  true,
-	'4':  true,
-	'5':  true,
-	'6':  true,
-	'7':  true,
-	'8':  true,
-	'9':  true,
-	'A':  true,
-	'B':  true,
-	'C':  true,
-	'D':  true,
-	'E':  true,
-	'F':  true,
-	'G':  true,
-	'H':  true,
-	'I':  true,
-	'J':  true,
-	'K':  true,
-	'L':  true,
-	'M':  true,
-	'N':  true,
-	'O':  true,
-	'P':  true,
-	'Q':  true,
-	'R':  true,
-	'S':  true,
-	'T':  true,
-	'U':  true,
-	'W':  true,
-	'V':  true,
-	'X':  true,
-	'Y':  true,
-	'Z':  true,
-	'^':  true,
-	'_':  true,
-	'`':  true,
-	'a':  true,
-	'b':  true,
-	'c':  true,
-	'd':  true,
-	'e':  true,
-	'f':  true,
-	'g':  true,
-	'h':  true,
-	'i':  true,
-	'j':  true,
-	'k':  true,
-	'l':  true,
-	'm':  true,
-	'n':  true,
-	'o':  true,
-	'p':  true,
-	'q':  true,
-	'r':  true,
-	's':  true,
-	't':  true,
-	'u':  true,
-	'v':  true,
-	'w':  true,
-	'x':  true,
-	'y':  true,
-	'z':  true,
-	'|':  true,
-	'~':  true,
-}
-
-func isToken(r rune) bool {
-	i := int(r)
-	return i < len(isTokenTable) && isTokenTable[i]
-}
-
-func isNotToken(r rune) bool {
-	return !isToken(r)
-}
-
-// headerValuesContainsToken reports whether any string in values
-// contains the provided token, ASCII case-insensitively.
-func headerValuesContainsToken(values []string, token string) bool {
-	for _, v := range values {
-		if headerValueContainsToken(v, token) {
-			return true
-		}
-	}
-	return false
-}
-
-// isOWS reports whether b is an optional whitespace byte, as defined
-// by RFC 7230 section 3.2.3.
-func isOWS(b byte) bool { return b == ' ' || b == '\t' }
-
-// trimOWS returns x with all optional whitespace removes from the
-// beginning and end.
-func trimOWS(x string) string {
-	// TODO: consider using strings.Trim(x, " \t") instead,
-	// if and when it's fast enough. See issue 10292.
-	// But this ASCII-only code will probably always beat UTF-8
-	// aware code.
-	for len(x) > 0 && isOWS(x[0]) {
-		x = x[1:]
-	}
-	for len(x) > 0 && isOWS(x[len(x)-1]) {
-		x = x[:len(x)-1]
-	}
-	return x
-}
-
-// headerValueContainsToken reports whether v (assumed to be a
-// 0#element, in the ABNF extension described in RFC 7230 section 7)
-// contains token amongst its comma-separated tokens, ASCII
-// case-insensitively.
-func headerValueContainsToken(v string, token string) bool {
-	v = trimOWS(v)
-	if comma := strings.IndexByte(v, ','); comma != -1 {
-		return tokenEqual(trimOWS(v[:comma]), token) || headerValueContainsToken(v[comma+1:], token)
-	}
-	return tokenEqual(v, token)
-}
-
-// lowerASCII returns the ASCII lowercase version of b.
-func lowerASCII(b byte) byte {
-	if 'A' <= b && b <= 'Z' {
-		return b + ('a' - 'A')
-	}
-	return b
-}
-
-// tokenEqual reports whether t1 and t2 are equal, ASCII case-insensitively.
-func tokenEqual(t1, t2 string) bool {
-	if len(t1) != len(t2) {
-		return false
-	}
-	for i, b := range t1 {
-		if b >= utf8.RuneSelf {
-			// No UTF-8 or non-ASCII allowed in tokens.
-			return false
-		}
-		if lowerASCII(byte(b)) != lowerASCII(t2[i]) {
-			return false
-		}
-	}
-	return true
-}
-
-// isLWS reports whether b is linear white space, according
-// to http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2
-//      LWS            = [CRLF] 1*( SP | HT )
-func isLWS(b byte) bool { return b == ' ' || b == '\t' }
-
-// isCTL reports whether b is a control byte, according
-// to http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2
-//      CTL            = <any US-ASCII control character
-//                       (octets 0 - 31) and DEL (127)>
-func isCTL(b byte) bool {
-	const del = 0x7f // a CTL
-	return b < ' ' || b == del
-}
-
-func validHeaderName(v string) bool {
-	if len(v) == 0 {
-		return false
-	}
-	for _, r := range v {
-		if !isToken(r) {
-			return false
-		}
-	}
-	return true
-}
-
-func validHostHeader(h string) bool {
-	// The latests spec is actually this:
-	//
-	// http://tools.ietf.org/html/rfc7230#section-5.4
-	//     Host = uri-host [ ":" port ]
-	//
-	// Where uri-host is:
-	//     http://tools.ietf.org/html/rfc3986#section-3.2.2
-	//
-	// But we're going to be much more lenient for now and just
-	// search for any byte that's not a valid byte in any of those
-	// expressions.
-	for i := 0; i < len(h); i++ {
-		if !validHostByte[h[i]] {
-			return false
-		}
-	}
-	return true
-}
-
-// See the validHostHeader comment.
-var validHostByte = [256]bool{
-	'0': true, '1': true, '2': true, '3': true, '4': true, '5': true, '6': true, '7': true,
-	'8': true, '9': true,
-
-	'a': true, 'b': true, 'c': true, 'd': true, 'e': true, 'f': true, 'g': true, 'h': true,
-	'i': true, 'j': true, 'k': true, 'l': true, 'm': true, 'n': true, 'o': true, 'p': true,
-	'q': true, 'r': true, 's': true, 't': true, 'u': true, 'v': true, 'w': true, 'x': true,
-	'y': true, 'z': true,
-
-	'A': true, 'B': true, 'C': true, 'D': true, 'E': true, 'F': true, 'G': true, 'H': true,
-	'I': true, 'J': true, 'K': true, 'L': true, 'M': true, 'N': true, 'O': true, 'P': true,
-	'Q': true, 'R': true, 'S': true, 'T': true, 'U': true, 'V': true, 'W': true, 'X': true,
-	'Y': true, 'Z': true,
-
-	'!':  true, // sub-delims
-	'$':  true, // sub-delims
-	'%':  true, // pct-encoded (and used in IPv6 zones)
-	'&':  true, // sub-delims
-	'(':  true, // sub-delims
-	')':  true, // sub-delims
-	'*':  true, // sub-delims
-	'+':  true, // sub-delims
-	',':  true, // sub-delims
-	'-':  true, // unreserved
-	'.':  true, // unreserved
-	':':  true, // IPv6address + Host expression's optional port
-	';':  true, // sub-delims
-	'=':  true, // sub-delims
-	'[':  true,
-	'\'': true, // sub-delims
-	']':  true,
-	'_':  true, // unreserved
-	'~':  true, // unreserved
-}
-
-// validHeaderValue reports whether v is a valid "field-value" according to
-// http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2 :
-//
-//        message-header = field-name ":" [ field-value ]
-//        field-value    = *( field-content | LWS )
-//        field-content  = <the OCTETs making up the field-value
-//                         and consisting of either *TEXT or combinations
-//                         of token, separators, and quoted-string>
-//
-// http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2 :
-//
-//        TEXT           = <any OCTET except CTLs,
-//                          but including LWS>
-//        LWS            = [CRLF] 1*( SP | HT )
-//        CTL            = <any US-ASCII control character
-//                         (octets 0 - 31) and DEL (127)>
-func validHeaderValue(v string) bool {
-	for i := 0; i < len(v); i++ {
-		b := v[i]
-		if isCTL(b) && !isLWS(b) {
-			return false
-		}
-	}
-	return true
-}
diff --git a/src/net/http/lex_test.go b/src/net/http/lex_test.go
deleted file mode 100644
index 986fda17dc..0000000000
--- a/src/net/http/lex_test.go
+++ /dev/null
@@ -1,101 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package http
-
-import (
-	"testing"
-)
-
-func isChar(c rune) bool { return c <= 127 }
-
-func isCtl(c rune) bool { return c <= 31 || c == 127 }
-
-func isSeparator(c rune) bool {
-	switch c {
-	case '(', ')', '<', '>', '@', ',', ';', ':', '\\', '"', '/', '[', ']', '?', '=', '{', '}', ' ', '\t':
-		return true
-	}
-	return false
-}
-
-func TestIsToken(t *testing.T) {
-	for i := 0; i <= 130; i++ {
-		r := rune(i)
-		expected := isChar(r) && !isCtl(r) && !isSeparator(r)
-		if isToken(r) != expected {
-			t.Errorf("isToken(0x%x) = %v", r, !expected)
-		}
-	}
-}
-
-func TestHeaderValuesContainsToken(t *testing.T) {
-	tests := []struct {
-		vals  []string
-		token string
-		want  bool
-	}{
-		{
-			vals:  []string{"foo"},
-			token: "foo",
-			want:  true,
-		},
-		{
-			vals:  []string{"bar", "foo"},
-			token: "foo",
-			want:  true,
-		},
-		{
-			vals:  []string{"foo"},
-			token: "FOO",
-			want:  true,
-		},
-		{
-			vals:  []string{"foo"},
-			token: "bar",
-			want:  false,
-		},
-		{
-			vals:  []string{" foo "},
-			token: "FOO",
-			want:  true,
-		},
-		{
-			vals:  []string{"foo,bar"},
-			token: "FOO",
-			want:  true,
-		},
-		{
-			vals:  []string{"bar,foo,bar"},
-			token: "FOO",
-			want:  true,
-		},
-		{
-			vals:  []string{"bar , foo"},
-			token: "FOO",
-			want:  true,
-		},
-		{
-			vals:  []string{"foo ,bar "},
-			token: "FOO",
-			want:  true,
-		},
-		{
-			vals:  []string{"bar, foo ,bar"},
-			token: "FOO",
-			want:  true,
-		},
-		{
-			vals:  []string{"bar , foo"},
-			token: "FOO",
-			want:  true,
-		},
-	}
-	for _, tt := range tests {
-		got := headerValuesContainsToken(tt.vals, tt.token)
-		if got != tt.want {
-			t.Errorf("headerValuesContainsToken(%q, %q) = %v; want %v", tt.vals, tt.token, got, tt.want)
-		}
-	}
-}
diff --git a/src/net/http/server.go b/src/net/http/server.go
index d4e38b6ad0..1a8c0fc6cc 100644
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -27,6 +27,8 @@ import (
 	"sync"
 	"sync/atomic"
 	"time"
+
+	"golang.org/x/net/lex/httplex"
 )
 
 // Errors used by the HTTP server.
@@ -783,15 +785,15 @@ func (c *conn) readRequest(ctx context.Context) (w *response, err error) {
 	if len(hosts) > 1 {
 		return nil, badRequestError("too many Host headers")
 	}
-	if len(hosts) == 1 && !validHostHeader(hosts[0]) {
+	if len(hosts) == 1 && !httplex.ValidHostHeader(hosts[0]) {
 		return nil, badRequestError("malformed Host header")
 	}
 	for k, vv := range req.Header {
-		if !validHeaderName(k) {
+		if !httplex.ValidHeaderFieldName(k) {
 			return nil, badRequestError("invalid header name")
 		}
 		for _, v := range vv {
-			if !validHeaderValue(v) {
+			if !httplex.ValidHeaderFieldValue(v) {
 				return nil, badRequestError("invalid header value")
 			}
 		}
diff --git a/src/net/http/transfer.go b/src/net/http/transfer.go
index 501e4be08c..b27ace638a 100644
--- a/src/net/http/transfer.go
+++ b/src/net/http/transfer.go
@@ -17,6 +17,8 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+
+	"golang.org/x/net/lex/httplex"
 )
 
 // ErrLineTooLong is returned when reading request or response bodies
@@ -561,9 +563,9 @@ func shouldClose(major, minor int, header Header, removeCloseHeader bool) bool {
 	}
 
 	conv := header["Connection"]
-	hasClose := headerValuesContainsToken(conv, "close")
+	hasClose := httplex.HeaderValuesContainsToken(conv, "close")
 	if major == 1 && minor == 0 {
-		return hasClose || !headerValuesContainsToken(conv, "keep-alive")
+		return hasClose || !httplex.HeaderValuesContainsToken(conv, "keep-alive")
 	}
 
 	if hasClose && removeCloseHeader {
diff --git a/src/net/http/transport.go b/src/net/http/transport.go
index 17e6270151..777501f5bd 100644
--- a/src/net/http/transport.go
+++ b/src/net/http/transport.go
@@ -26,6 +26,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"golang.org/x/net/lex/httplex"
 )
 
 // DefaultTransport is the default implementation of Transport and is
@@ -324,11 +326,11 @@ func (t *Transport) RoundTrip(req *Request) (*Response, error) {
 	isHTTP := scheme == "http" || scheme == "https"
 	if isHTTP {
 		for k, vv := range req.Header {
-			if !validHeaderName(k) {
+			if !httplex.ValidHeaderFieldName(k) {
 				return nil, fmt.Errorf("net/http: invalid header field name %q", k)
 			}
 			for _, v := range vv {
-				if !validHeaderValue(v) {
+				if !httplex.ValidHeaderFieldValue(v) {
 					return nil, fmt.Errorf("net/http: invalid header field value %q for key %v", v, k)
 				}
 			}