From ce060acf9d64e943d9ea1d5d5614defe3807068b Mon Sep 17 00:00:00 2001
From: Lavanya Sirigudi <65212197+lavanya-f5@users.noreply.github.com>
Date: Mon, 20 Sep 2021 18:56:05 +0530
Subject: [PATCH] Upgrade golang.org/x/net for resolving CVE-2021-33194 (#1997)

---
 go.mod                                        |   1 +
 go.sum                                        |   2 +
 vendor/golang.org/x/net/html/parse.go         |  24 +++-
 vendor/golang.org/x/net/http2/ascii.go        |  49 ++++++++
 .../x/net/http2/client_conn_pool.go           |  79 ++++++++----
 vendor/golang.org/x/net/http2/go115.go        |  27 +++++
 vendor/golang.org/x/net/http2/headermap.go    |   7 +-
 vendor/golang.org/x/net/http2/not_go115.go    |  31 +++++
 vendor/golang.org/x/net/http2/server.go       |  26 ++--
 vendor/golang.org/x/net/http2/transport.go    |  68 ++++++-----
 vendor/golang.org/x/net/http2/write.go        |   7 +-
 vendor/golang.org/x/net/idna/idna10.0.0.go    | 113 ++++++++++++------
 vendor/golang.org/x/net/idna/idna9.0.0.go     |  93 +++++++++-----
 .../x/net/internal/socket/mmsghdr_unix.go     | 103 +++++++++++++---
 .../x/net/internal/socket/msghdr_linux.go     |   3 +
 .../x/net/internal/socket/rawconn_mmsg.go     |  16 ++-
 .../x/net/internal/socket/rawconn_msg.go      |   4 +-
 .../x/net/internal/socket/sys_posix.go        |  23 ++--
 vendor/modules.txt                            |   3 +-
 19 files changed, 498 insertions(+), 181 deletions(-)
 create mode 100644 vendor/golang.org/x/net/http2/ascii.go
 create mode 100644 vendor/golang.org/x/net/http2/go115.go
 create mode 100644 vendor/golang.org/x/net/http2/not_go115.go

diff --git a/go.mod b/go.mod
index b95dedfb1..ffcaee52a 100644
--- a/go.mod
+++ b/go.mod
@@ -20,6 +20,7 @@ require (
 	github.com/xeipuuv/gojsonschema v1.1.0
 	golang.org/x/crypto v0.0.0-20210220033148-5ea612d1eb83
 	golang.org/x/mod v0.4.2
+	golang.org/x/net v0.0.0-20210520170846-37e1c6afe023 // indirect
 	k8s.io/api v0.21.2
 	k8s.io/apiextensions-apiserver v0.21.2
 	k8s.io/apimachinery v0.21.2
diff --git a/go.sum b/go.sum
index 0ebb9c959..0670ffc66 100644
--- a/go.sum
+++ b/go.sum
@@ -482,6 +482,8 @@ golang.org/x/net v0.0.0-20210224082022-3d97a244fca7/go.mod h1:m0MpNAwzfU5UDzcl9v
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20210428140749-89ef3d95e781 h1:DzZ89McO9/gWPsQXS/FVKAlG02ZjaQ6AlZRBimEYOd0=
 golang.org/x/net v0.0.0-20210428140749-89ef3d95e781/go.mod h1:OJAsFXCWl8Ukc7SiCT/9KSuxbyM7479/AVlXFRxuMCk=
+golang.org/x/net v0.0.0-20210520170846-37e1c6afe023 h1:ADo5wSpq2gqaCGQWzk7S5vd//0iyyLeAratkEoG5dLE=
+golang.org/x/net v0.0.0-20210520170846-37e1c6afe023/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
diff --git a/vendor/golang.org/x/net/html/parse.go b/vendor/golang.org/x/net/html/parse.go
index f91466f7c..038941d70 100644
--- a/vendor/golang.org/x/net/html/parse.go
+++ b/vendor/golang.org/x/net/html/parse.go
@@ -663,6 +663,24 @@ func inHeadIM(p *parser) bool {
 			// Ignore the token.
 			return true
 		case a.Template:
+			// TODO: remove this divergence from the HTML5 spec.
+			//
+			// We don't handle all of the corner cases when mixing foreign
+			// content (i.e. <math> or <svg>) with <template>. Without this
+			// early return, we can get into an infinite loop, possibly because
+			// of the "TODO... further divergence" a little below.
+			//
+			// As a workaround, if we are mixing foreign content and templates,
+			// just ignore the rest of the HTML. Foreign content is rare and a
+			// relatively old HTML feature. Templates are also rare and a
+			// relatively new HTML feature. Their combination is very rare.
+			for _, e := range p.oe {
+				if e.Namespace != "" {
+					p.im = ignoreTheRemainingTokens
+					return true
+				}
+			}
+
 			p.addElement()
 			p.afe = append(p.afe, &scopeMarker)
 			p.framesetOK = false
@@ -683,7 +701,7 @@ func inHeadIM(p *parser) bool {
 			if !p.oe.contains(a.Template) {
 				return true
 			}
-			// TODO: remove this divergence from the HTML5 spec.
+			// TODO: remove this further divergence from the HTML5 spec.
 			//
 			// See https://bugs.chromium.org/p/chromium/issues/detail?id=829668
 			p.generateImpliedEndTags()
@@ -2127,6 +2145,10 @@ func afterAfterFramesetIM(p *parser) bool {
 	return true
 }
 
+func ignoreTheRemainingTokens(p *parser) bool {
+	return true
+}
+
 const whitespaceOrNUL = whitespace + "\x00"
 
 // Section 12.2.6.5
diff --git a/vendor/golang.org/x/net/http2/ascii.go b/vendor/golang.org/x/net/http2/ascii.go
new file mode 100644
index 000000000..0c58d727c
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/ascii.go
@@ -0,0 +1,49 @@
+// Copyright 2021 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 http2
+
+import "strings"
+
+// asciiEqualFold is strings.EqualFold, ASCII only. It reports whether s and t
+// are equal, ASCII-case-insensitively.
+func asciiEqualFold(s, t string) bool {
+	if len(s) != len(t) {
+		return false
+	}
+	for i := 0; i < len(s); i++ {
+		if lower(s[i]) != lower(t[i]) {
+			return false
+		}
+	}
+	return true
+}
+
+// lower returns the ASCII lowercase version of b.
+func lower(b byte) byte {
+	if 'A' <= b && b <= 'Z' {
+		return b + ('a' - 'A')
+	}
+	return b
+}
+
+// isASCIIPrint returns whether s is ASCII and printable according to
+// https://tools.ietf.org/html/rfc20#section-4.2.
+func isASCIIPrint(s string) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] < ' ' || s[i] > '~' {
+			return false
+		}
+	}
+	return true
+}
+
+// asciiToLower returns the lowercase version of s if s is ASCII and printable,
+// and whether or not it was.
+func asciiToLower(s string) (lower string, ok bool) {
+	if !isASCIIPrint(s) {
+		return "", false
+	}
+	return strings.ToLower(s), true
+}
diff --git a/vendor/golang.org/x/net/http2/client_conn_pool.go b/vendor/golang.org/x/net/http2/client_conn_pool.go
index 3a67636fe..652bc11a0 100644
--- a/vendor/golang.org/x/net/http2/client_conn_pool.go
+++ b/vendor/golang.org/x/net/http2/client_conn_pool.go
@@ -7,7 +7,9 @@
 package http2
 
 import (
+	"context"
 	"crypto/tls"
+	"errors"
 	"net/http"
 	"sync"
 )
@@ -78,61 +80,69 @@ func (p *clientConnPool) getClientConn(req *http.Request, addr string, dialOnMis
 		// It gets its own connection.
 		traceGetConn(req, addr)
 		const singleUse = true
-		cc, err := p.t.dialClientConn(addr, singleUse)
+		cc, err := p.t.dialClientConn(req.Context(), addr, singleUse)
 		if err != nil {
 			return nil, err
 		}
 		return cc, nil
 	}
-	p.mu.Lock()
-	for _, cc := range p.conns[addr] {
-		if st := cc.idleState(); st.canTakeNewRequest {
-			if p.shouldTraceGetConn(st) {
-				traceGetConn(req, addr)
+	for {
+		p.mu.Lock()
+		for _, cc := range p.conns[addr] {
+			if st := cc.idleState(); st.canTakeNewRequest {
+				if p.shouldTraceGetConn(st) {
+					traceGetConn(req, addr)
+				}
+				p.mu.Unlock()
+				return cc, nil
 			}
+		}
+		if !dialOnMiss {
 			p.mu.Unlock()
-			return cc, nil
+			return nil, ErrNoCachedConn
 		}
-	}
-	if !dialOnMiss {
+		traceGetConn(req, addr)
+		call := p.getStartDialLocked(req.Context(), addr)
 		p.mu.Unlock()
-		return nil, ErrNoCachedConn
+		<-call.done
+		if shouldRetryDial(call, req) {
+			continue
+		}
+		return call.res, call.err
 	}
-	traceGetConn(req, addr)
-	call := p.getStartDialLocked(addr)
-	p.mu.Unlock()
-	<-call.done
-	return call.res, call.err
 }
 
 // dialCall is an in-flight Transport dial call to a host.
 type dialCall struct {
-	_    incomparable
-	p    *clientConnPool
+	_ incomparable
+	p *clientConnPool
+	// the context associated with the request
+	// that created this dialCall
+	ctx  context.Context
 	done chan struct{} // closed when done
 	res  *ClientConn   // valid after done is closed
 	err  error         // valid after done is closed
 }
 
 // requires p.mu is held.
-func (p *clientConnPool) getStartDialLocked(addr string) *dialCall {
+func (p *clientConnPool) getStartDialLocked(ctx context.Context, addr string) *dialCall {
 	if call, ok := p.dialing[addr]; ok {
 		// A dial is already in-flight. Don't start another.
 		return call
 	}
-	call := &dialCall{p: p, done: make(chan struct{})}
+	call := &dialCall{p: p, done: make(chan struct{}), ctx: ctx}
 	if p.dialing == nil {
 		p.dialing = make(map[string]*dialCall)
 	}
 	p.dialing[addr] = call
-	go call.dial(addr)
+	go call.dial(call.ctx, addr)
 	return call
 }
 
 // run in its own goroutine.
-func (c *dialCall) dial(addr string) {
+func (c *dialCall) dial(ctx context.Context, addr string) {
 	const singleUse = false // shared conn
-	c.res, c.err = c.p.t.dialClientConn(addr, singleUse)
+	c.res, c.err = c.p.t.dialClientConn(ctx, addr, singleUse)
 	close(c.done)
 
 	c.p.mu.Lock()
@@ -276,3 +286,28 @@ type noDialClientConnPool struct{ *clientConnPool }
 func (p noDialClientConnPool) GetClientConn(req *http.Request, addr string) (*ClientConn, error) {
 	return p.getClientConn(req, addr, noDialOnMiss)
 }
+
+// shouldRetryDial reports whether the current request should
+// retry dialing after the call finished unsuccessfully, for example
+// if the dial was canceled because of a context cancellation or
+// deadline expiry.
+func shouldRetryDial(call *dialCall, req *http.Request) bool {
+	if call.err == nil {
+		// No error, no need to retry
+		return false
+	}
+	if call.ctx == req.Context() {
+		// If the call has the same context as the request, the dial
+		// should not be retried, since any cancellation will have come
+		// from this request.
+		return false
+	}
+	if !errors.Is(call.err, context.Canceled) && !errors.Is(call.err, context.DeadlineExceeded) {
+		// If the call error is not because of a context cancellation or a deadline expiry,
+		// the dial should not be retried.
+		return false
+	}
+	// Only retry if the error is a context cancellation error or deadline expiry
+	// and the context associated with the call was canceled or expired.
+	return call.ctx.Err() != nil
+}
diff --git a/vendor/golang.org/x/net/http2/go115.go b/vendor/golang.org/x/net/http2/go115.go
new file mode 100644
index 000000000..908af1ab9
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/go115.go
@@ -0,0 +1,27 @@
+// Copyright 2021 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.
+
+//go:build go1.15
+// +build go1.15
+
+package http2
+
+import (
+	"context"
+	"crypto/tls"
+)
+
+// dialTLSWithContext uses tls.Dialer, added in Go 1.15, to open a TLS
+// connection.
+func (t *Transport) dialTLSWithContext(ctx context.Context, network, addr string, cfg *tls.Config) (*tls.Conn, error) {
+	dialer := &tls.Dialer{
+		Config: cfg,
+	}
+	cn, err := dialer.DialContext(ctx, network, addr)
+	if err != nil {
+		return nil, err
+	}
+	tlsCn := cn.(*tls.Conn) // DialContext comment promises this will always succeed
+	return tlsCn, nil
+}
diff --git a/vendor/golang.org/x/net/http2/headermap.go b/vendor/golang.org/x/net/http2/headermap.go
index c3ff3fa1c..9e12941da 100644
--- a/vendor/golang.org/x/net/http2/headermap.go
+++ b/vendor/golang.org/x/net/http2/headermap.go
@@ -6,7 +6,6 @@ package http2
 
 import (
 	"net/http"
-	"strings"
 	"sync"
 )
 
@@ -79,10 +78,10 @@ func buildCommonHeaderMaps() {
 	}
 }
 
-func lowerHeader(v string) string {
+func lowerHeader(v string) (lower string, ascii bool) {
 	buildCommonHeaderMapsOnce()
 	if s, ok := commonLowerHeader[v]; ok {
-		return s
+		return s, true
 	}
-	return strings.ToLower(v)
+	return asciiToLower(v)
 }
diff --git a/vendor/golang.org/x/net/http2/not_go115.go b/vendor/golang.org/x/net/http2/not_go115.go
new file mode 100644
index 000000000..e6c04cf7a
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/not_go115.go
@@ -0,0 +1,31 @@
+// Copyright 2021 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.
+
+//go:build !go1.15
+// +build !go1.15
+
+package http2
+
+import (
+	"context"
+	"crypto/tls"
+)
+
+// dialTLSWithContext opens a TLS connection.
+func (t *Transport) dialTLSWithContext(ctx context.Context, network, addr string, cfg *tls.Config) (*tls.Conn, error) {
+	cn, err := tls.Dial(network, addr, cfg)
+	if err != nil {
+		return nil, err
+	}
+	if err := cn.Handshake(); err != nil {
+		return nil, err
+	}
+	if cfg.InsecureSkipVerify {
+		return cn, nil
+	}
+	if err := cn.VerifyHostname(cfg.ServerName); err != nil {
+		return nil, err
+	}
+	return cn, nil
+}
diff --git a/vendor/golang.org/x/net/http2/server.go b/vendor/golang.org/x/net/http2/server.go
index e125bbd2a..09bc70533 100644
--- a/vendor/golang.org/x/net/http2/server.go
+++ b/vendor/golang.org/x/net/http2/server.go
@@ -231,13 +231,12 @@ func ConfigureServer(s *http.Server, conf *Server) error {
 
 	if s.TLSConfig == nil {
 		s.TLSConfig = new(tls.Config)
-	} else if s.TLSConfig.CipherSuites != nil {
-		// If they already provided a CipherSuite list, return
-		// an error if it has a bad order or is missing
-		// ECDHE_RSA_WITH_AES_128_GCM_SHA256 or ECDHE_ECDSA_WITH_AES_128_GCM_SHA256.
+	} else if s.TLSConfig.CipherSuites != nil && s.TLSConfig.MinVersion < tls.VersionTLS13 {
+		// If they already provided a TLS 1.0–1.2 CipherSuite list, return an
+		// error if it is missing ECDHE_RSA_WITH_AES_128_GCM_SHA256 or
+		// ECDHE_ECDSA_WITH_AES_128_GCM_SHA256.
 		haveRequired := false
-		sawBad := false
-		for i, cs := range s.TLSConfig.CipherSuites {
+		for _, cs := range s.TLSConfig.CipherSuites {
 			switch cs {
 			case tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
 				// Alternative MTI cipher to not discourage ECDSA-only servers.
@@ -245,14 +244,9 @@ func ConfigureServer(s *http.Server, conf *Server) error {
 				tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256:
 				haveRequired = true
 			}
-			if isBadCipher(cs) {
-				sawBad = true
-			} else if sawBad {
-				return fmt.Errorf("http2: TLSConfig.CipherSuites index %d contains an HTTP/2-approved cipher suite (%#04x), but it comes after unapproved cipher suites. With this configuration, clients that don't support previous, approved cipher suites may be given an unapproved one and reject the connection.", i, cs)
-			}
 		}
 		if !haveRequired {
-			return fmt.Errorf("http2: TLSConfig.CipherSuites is missing an HTTP/2-required AES_128_GCM_SHA256 cipher (need at least one of TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 or TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256).")
+			return fmt.Errorf("http2: TLSConfig.CipherSuites is missing an HTTP/2-required AES_128_GCM_SHA256 cipher (need at least one of TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 or TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256)")
 		}
 	}
 
@@ -2789,8 +2783,12 @@ func (w *responseWriter) Push(target string, opts *http.PushOptions) error {
 		// but PUSH_PROMISE requests cannot have a body.
 		// http://tools.ietf.org/html/rfc7540#section-8.2
 		// Also disallow Host, since the promised URL must be absolute.
-		switch strings.ToLower(k) {
-		case "content-length", "content-encoding", "trailer", "te", "expect", "host":
+		if asciiEqualFold(k, "content-length") ||
+			asciiEqualFold(k, "content-encoding") ||
+			asciiEqualFold(k, "trailer") ||
+			asciiEqualFold(k, "te") ||
+			asciiEqualFold(k, "expect") ||
+			asciiEqualFold(k, "host") {
 			return fmt.Errorf("promised request headers cannot include %q", k)
 		}
 	}
diff --git a/vendor/golang.org/x/net/http2/transport.go b/vendor/golang.org/x/net/http2/transport.go
index 7688d72c3..7bd4b9c19 100644
--- a/vendor/golang.org/x/net/http2/transport.go
+++ b/vendor/golang.org/x/net/http2/transport.go
@@ -564,12 +564,12 @@ func canRetryError(err error) bool {
 	return false
 }
 
-func (t *Transport) dialClientConn(addr string, singleUse bool) (*ClientConn, error) {
+func (t *Transport) dialClientConn(ctx context.Context, addr string, singleUse bool) (*ClientConn, error) {
 	host, _, err := net.SplitHostPort(addr)
 	if err != nil {
 		return nil, err
 	}
-	tconn, err := t.dialTLS()("tcp", addr, t.newTLSConfig(host))
+	tconn, err := t.dialTLS(ctx)("tcp", addr, t.newTLSConfig(host))
 	if err != nil {
 		return nil, err
 	}
@@ -590,34 +590,24 @@ func (t *Transport) newTLSConfig(host string) *tls.Config {
 	return cfg
 }
 
-func (t *Transport) dialTLS() func(string, string, *tls.Config) (net.Conn, error) {
+func (t *Transport) dialTLS(ctx context.Context) func(string, string, *tls.Config) (net.Conn, error) {
 	if t.DialTLS != nil {
 		return t.DialTLS
 	}
-	return t.dialTLSDefault
-}
-
-func (t *Transport) dialTLSDefault(network, addr string, cfg *tls.Config) (net.Conn, error) {
-	cn, err := tls.Dial(network, addr, cfg)
-	if err != nil {
-		return nil, err
-	}
-	if err := cn.Handshake(); err != nil {
-		return nil, err
-	}
-	if !cfg.InsecureSkipVerify {
-		if err := cn.VerifyHostname(cfg.ServerName); err != nil {
+	return func(network, addr string, cfg *tls.Config) (net.Conn, error) {
+		tlsCn, err := t.dialTLSWithContext(ctx, network, addr, cfg)
+		if err != nil {
 			return nil, err
 		}
+		state := tlsCn.ConnectionState()
+		if p := state.NegotiatedProtocol; p != NextProtoTLS {
+			return nil, fmt.Errorf("http2: unexpected ALPN protocol %q; want %q", p, NextProtoTLS)
+		}
+		if !state.NegotiatedProtocolIsMutual {
+			return nil, errors.New("http2: could not negotiate protocol mutually")
+		}
+		return tlsCn, nil
 	}
-	state := cn.ConnectionState()
-	if p := state.NegotiatedProtocol; p != NextProtoTLS {
-		return nil, fmt.Errorf("http2: unexpected ALPN protocol %q; want %q", p, NextProtoTLS)
-	}
-	if !state.NegotiatedProtocolIsMutual {
-		return nil, errors.New("http2: could not negotiate protocol mutually")
-	}
-	return cn, nil
 }
 
 // disableKeepAlives reports whether connections should be closed as
@@ -1005,7 +995,7 @@ func checkConnHeaders(req *http.Request) error {
 	if vv := req.Header["Transfer-Encoding"]; len(vv) > 0 && (len(vv) > 1 || vv[0] != "" && vv[0] != "chunked") {
 		return fmt.Errorf("http2: invalid Transfer-Encoding request header: %q", vv)
 	}
-	if vv := req.Header["Connection"]; len(vv) > 0 && (len(vv) > 1 || vv[0] != "" && !strings.EqualFold(vv[0], "close") && !strings.EqualFold(vv[0], "keep-alive")) {
+	if vv := req.Header["Connection"]; len(vv) > 0 && (len(vv) > 1 || vv[0] != "" && !asciiEqualFold(vv[0], "close") && !asciiEqualFold(vv[0], "keep-alive")) {
 		return fmt.Errorf("http2: invalid Connection request header: %q", vv)
 	}
 	return nil
@@ -1531,19 +1521,21 @@ func (cc *ClientConn) encodeHeaders(req *http.Request, addGzipHeader bool, trail
 
 		var didUA bool
 		for k, vv := range req.Header {
-			if strings.EqualFold(k, "host") || strings.EqualFold(k, "content-length") {
+			if asciiEqualFold(k, "host") || asciiEqualFold(k, "content-length") {
 				// Host is :authority, already sent.
 				// Content-Length is automatic, set below.
 				continue
-			} else if strings.EqualFold(k, "connection") || strings.EqualFold(k, "proxy-connection") ||
-				strings.EqualFold(k, "transfer-encoding") || strings.EqualFold(k, "upgrade") ||
-				strings.EqualFold(k, "keep-alive") {
+			} else if asciiEqualFold(k, "connection") ||
+				asciiEqualFold(k, "proxy-connection") ||
+				asciiEqualFold(k, "transfer-encoding") ||
+				asciiEqualFold(k, "upgrade") ||
+				asciiEqualFold(k, "keep-alive") {
 				// Per 8.1.2.2 Connection-Specific Header
 				// Fields, don't send connection-specific
 				// fields. We have already checked if any
 				// are error-worthy so just ignore the rest.
 				continue
-			} else if strings.EqualFold(k, "user-agent") {
+			} else if asciiEqualFold(k, "user-agent") {
 				// Match Go's http1 behavior: at most one
 				// User-Agent. If set to nil or empty string,
 				// then omit it. Otherwise if not mentioned,
@@ -1556,7 +1548,7 @@ func (cc *ClientConn) encodeHeaders(req *http.Request, addGzipHeader bool, trail
 				if vv[0] == "" {
 					continue
 				}
-			} else if strings.EqualFold(k, "cookie") {
+			} else if asciiEqualFold(k, "cookie") {
 				// Per 8.1.2.5 To allow for better compression efficiency, the
 				// Cookie header field MAY be split into separate header fields,
 				// each with one or more cookie-pairs.
@@ -1615,7 +1607,12 @@ func (cc *ClientConn) encodeHeaders(req *http.Request, addGzipHeader bool, trail
 
 	// Header list size is ok. Write the headers.
 	enumerateHeaders(func(name, value string) {
-		name = strings.ToLower(name)
+		name, ascii := asciiToLower(name)
+		if !ascii {
+			// Skip writing invalid headers. Per RFC 7540, Section 8.1.2, header
+			// field names have to be ASCII characters (just as in HTTP/1.x).
+			return
+		}
 		cc.writeHeader(name, value)
 		if traceHeaders {
 			traceWroteHeaderField(trace, name, value)
@@ -1663,9 +1660,14 @@ func (cc *ClientConn) encodeTrailers(req *http.Request) ([]byte, error) {
 	}
 
 	for k, vv := range req.Trailer {
+		lowKey, ascii := asciiToLower(k)
+		if !ascii {
+			// Skip writing invalid headers. Per RFC 7540, Section 8.1.2, header
+			// field names have to be ASCII characters (just as in HTTP/1.x).
+			continue
+		}
 		// Transfer-Encoding, etc.. have already been filtered at the
 		// start of RoundTrip
-		lowKey := strings.ToLower(k)
 		for _, v := range vv {
 			cc.writeHeader(lowKey, v)
 		}
diff --git a/vendor/golang.org/x/net/http2/write.go b/vendor/golang.org/x/net/http2/write.go
index 3849bc263..33f61398a 100644
--- a/vendor/golang.org/x/net/http2/write.go
+++ b/vendor/golang.org/x/net/http2/write.go
@@ -341,7 +341,12 @@ func encodeHeaders(enc *hpack.Encoder, h http.Header, keys []string) {
 	}
 	for _, k := range keys {
 		vv := h[k]
-		k = lowerHeader(k)
+		k, ascii := lowerHeader(k)
+		if !ascii {
+			// Skip writing invalid headers. Per RFC 7540, Section 8.1.2, header
+			// field names have to be ASCII characters (just as in HTTP/1.x).
+			continue
+		}
 		if !validWireHeaderFieldName(k) {
 			// Skip it as backup paranoia. Per
 			// golang.org/issue/14048, these should
diff --git a/vendor/golang.org/x/net/idna/idna10.0.0.go b/vendor/golang.org/x/net/idna/idna10.0.0.go
index 7e69ee1b2..5208ba6cb 100644
--- a/vendor/golang.org/x/net/idna/idna10.0.0.go
+++ b/vendor/golang.org/x/net/idna/idna10.0.0.go
@@ -67,15 +67,14 @@ func Transitional(transitional bool) Option {
 
 // VerifyDNSLength sets whether a Profile should fail if any of the IDN parts
 // are longer than allowed by the RFC.
+//
+// This option corresponds to the VerifyDnsLength flag in UTS #46.
 func VerifyDNSLength(verify bool) Option {
 	return func(o *options) { o.verifyDNSLength = verify }
 }
 
 // RemoveLeadingDots removes leading label separators. Leading runes that map to
 // dots, such as U+3002 IDEOGRAPHIC FULL STOP, are removed as well.
-//
-// This is the behavior suggested by the UTS #46 and is adopted by some
-// browsers.
 func RemoveLeadingDots(remove bool) Option {
 	return func(o *options) { o.removeLeadingDots = remove }
 }
@@ -83,6 +82,8 @@ func RemoveLeadingDots(remove bool) Option {
 // ValidateLabels sets whether to check the mandatory label validation criteria
 // as defined in Section 5.4 of RFC 5891. This includes testing for correct use
 // of hyphens ('-'), normalization, validity of runes, and the context rules.
+// In particular, ValidateLabels also sets the CheckHyphens and CheckJoiners flags
+// in UTS #46.
 func ValidateLabels(enable bool) Option {
 	return func(o *options) {
 		// Don't override existing mappings, but set one that at least checks
@@ -91,25 +92,48 @@ func ValidateLabels(enable bool) Option {
 			o.mapping = normalize
 		}
 		o.trie = trie
-		o.validateLabels = enable
-		o.fromPuny = validateFromPunycode
+		o.checkJoiners = enable
+		o.checkHyphens = enable
+		if enable {
+			o.fromPuny = validateFromPunycode
+		} else {
+			o.fromPuny = nil
+		}
+	}
+}
+
+// CheckHyphens sets whether to check for correct use of hyphens ('-') in
+// labels. Most web browsers do not have this option set, since labels such as
+// "r3---sn-apo3qvuoxuxbt-j5pe" are in common use.
+//
+// This option corresponds to the CheckHyphens flag in UTS #46.
+func CheckHyphens(enable bool) Option {
+	return func(o *options) { o.checkHyphens = enable }
+}
+
+// CheckJoiners sets whether to check the ContextJ rules as defined in Appendix
+// A of RFC 5892, concerning the use of joiner runes.
+//
+// This option corresponds to the CheckJoiners flag in UTS #46.
+func CheckJoiners(enable bool) Option {
+	return func(o *options) {
+		o.trie = trie
+		o.checkJoiners = enable
 	}
 }
 
 // StrictDomainName limits the set of permissible ASCII characters to those
 // allowed in domain names as defined in RFC 1034 (A-Z, a-z, 0-9 and the
-// hyphen). This is set by default for MapForLookup and ValidateForRegistration.
+// hyphen). This is set by default for MapForLookup and ValidateForRegistration,
+// but is only useful if ValidateLabels is set.
 //
 // This option is useful, for instance, for browsers that allow characters
 // outside this range, for example a '_' (U+005F LOW LINE). See
-// http://www.rfc-editor.org/std/std3.txt for more details This option
-// corresponds to the UseSTD3ASCIIRules option in UTS #46.
+// http://www.rfc-editor.org/std/std3.txt for more details.
+//
+// This option corresponds to the UseSTD3ASCIIRules flag in UTS #46.
 func StrictDomainName(use bool) Option {
-	return func(o *options) {
-		o.trie = trie
-		o.useSTD3Rules = use
-		o.fromPuny = validateFromPunycode
-	}
+	return func(o *options) { o.useSTD3Rules = use }
 }
 
 // NOTE: the following options pull in tables. The tables should not be linked
@@ -117,6 +141,8 @@ func StrictDomainName(use bool) Option {
 
 // BidiRule enables the Bidi rule as defined in RFC 5893. Any application
 // that relies on proper validation of labels should include this rule.
+//
+// This option corresponds to the CheckBidi flag in UTS #46.
 func BidiRule() Option {
 	return func(o *options) { o.bidirule = bidirule.ValidString }
 }
@@ -152,7 +178,8 @@ func MapForLookup() Option {
 type options struct {
 	transitional      bool
 	useSTD3Rules      bool
-	validateLabels    bool
+	checkHyphens      bool
+	checkJoiners      bool
 	verifyDNSLength   bool
 	removeLeadingDots bool
 
@@ -225,8 +252,11 @@ func (p *Profile) String() string {
 	if p.useSTD3Rules {
 		s += ":UseSTD3Rules"
 	}
-	if p.validateLabels {
-		s += ":ValidateLabels"
+	if p.checkHyphens {
+		s += ":CheckHyphens"
+	}
+	if p.checkJoiners {
+		s += ":CheckJoiners"
 	}
 	if p.verifyDNSLength {
 		s += ":VerifyDNSLength"
@@ -254,26 +284,29 @@ var (
 
 	punycode = &Profile{}
 	lookup   = &Profile{options{
-		transitional:   true,
-		useSTD3Rules:   true,
-		validateLabels: true,
-		trie:           trie,
-		fromPuny:       validateFromPunycode,
-		mapping:        validateAndMap,
-		bidirule:       bidirule.ValidString,
+		transitional: true,
+		useSTD3Rules: true,
+		checkHyphens: true,
+		checkJoiners: true,
+		trie:         trie,
+		fromPuny:     validateFromPunycode,
+		mapping:      validateAndMap,
+		bidirule:     bidirule.ValidString,
 	}}
 	display = &Profile{options{
-		useSTD3Rules:   true,
-		validateLabels: true,
-		trie:           trie,
-		fromPuny:       validateFromPunycode,
-		mapping:        validateAndMap,
-		bidirule:       bidirule.ValidString,
+		useSTD3Rules: true,
+		checkHyphens: true,
+		checkJoiners: true,
+		trie:         trie,
+		fromPuny:     validateFromPunycode,
+		mapping:      validateAndMap,
+		bidirule:     bidirule.ValidString,
 	}}
 	registration = &Profile{options{
 		useSTD3Rules:    true,
-		validateLabels:  true,
 		verifyDNSLength: true,
+		checkHyphens:    true,
+		checkJoiners:    true,
 		trie:            trie,
 		fromPuny:        validateFromPunycode,
 		mapping:         validateRegistration,
@@ -340,7 +373,7 @@ func (p *Profile) process(s string, toASCII bool) (string, error) {
 			}
 			isBidi = isBidi || bidirule.DirectionString(u) != bidi.LeftToRight
 			labels.set(u)
-			if err == nil && p.validateLabels {
+			if err == nil && p.fromPuny != nil {
 				err = p.fromPuny(p, u)
 			}
 			if err == nil {
@@ -681,16 +714,18 @@ func (p *Profile) validateLabel(s string) (err error) {
 		}
 		return nil
 	}
-	if !p.validateLabels {
-		return nil
-	}
-	trie := p.trie // p.validateLabels is only set if trie is set.
-	if len(s) > 4 && s[2] == '-' && s[3] == '-' {
-		return &labelError{s, "V2"}
+	if p.checkHyphens {
+		if len(s) > 4 && s[2] == '-' && s[3] == '-' {
+			return &labelError{s, "V2"}
+		}
+		if s[0] == '-' || s[len(s)-1] == '-' {
+			return &labelError{s, "V3"}
+		}
 	}
-	if s[0] == '-' || s[len(s)-1] == '-' {
-		return &labelError{s, "V3"}
+	if !p.checkJoiners {
+		return nil
 	}
+	trie := p.trie // p.checkJoiners is only set if trie is set.
 	// TODO: merge the use of this in the trie.
 	v, sz := trie.lookupString(s)
 	x := info(v)
diff --git a/vendor/golang.org/x/net/idna/idna9.0.0.go b/vendor/golang.org/x/net/idna/idna9.0.0.go
index 7c7456374..55f718f12 100644
--- a/vendor/golang.org/x/net/idna/idna9.0.0.go
+++ b/vendor/golang.org/x/net/idna/idna9.0.0.go
@@ -66,15 +66,14 @@ func Transitional(transitional bool) Option {
 
 // VerifyDNSLength sets whether a Profile should fail if any of the IDN parts
 // are longer than allowed by the RFC.
+//
+// This option corresponds to the VerifyDnsLength flag in UTS #46.
 func VerifyDNSLength(verify bool) Option {
 	return func(o *options) { o.verifyDNSLength = verify }
 }
 
 // RemoveLeadingDots removes leading label separators. Leading runes that map to
 // dots, such as U+3002 IDEOGRAPHIC FULL STOP, are removed as well.
-//
-// This is the behavior suggested by the UTS #46 and is adopted by some
-// browsers.
 func RemoveLeadingDots(remove bool) Option {
 	return func(o *options) { o.removeLeadingDots = remove }
 }
@@ -82,6 +81,8 @@ func RemoveLeadingDots(remove bool) Option {
 // ValidateLabels sets whether to check the mandatory label validation criteria
 // as defined in Section 5.4 of RFC 5891. This includes testing for correct use
 // of hyphens ('-'), normalization, validity of runes, and the context rules.
+// In particular, ValidateLabels also sets the CheckHyphens and CheckJoiners flags
+// in UTS #46.
 func ValidateLabels(enable bool) Option {
 	return func(o *options) {
 		// Don't override existing mappings, but set one that at least checks
@@ -90,25 +91,48 @@ func ValidateLabels(enable bool) Option {
 			o.mapping = normalize
 		}
 		o.trie = trie
-		o.validateLabels = enable
-		o.fromPuny = validateFromPunycode
+		o.checkJoiners = enable
+		o.checkHyphens = enable
+		if enable {
+			o.fromPuny = validateFromPunycode
+		} else {
+			o.fromPuny = nil
+		}
+	}
+}
+
+// CheckHyphens sets whether to check for correct use of hyphens ('-') in
+// labels. Most web browsers do not have this option set, since labels such as
+// "r3---sn-apo3qvuoxuxbt-j5pe" are in common use.
+//
+// This option corresponds to the CheckHyphens flag in UTS #46.
+func CheckHyphens(enable bool) Option {
+	return func(o *options) { o.checkHyphens = enable }
+}
+
+// CheckJoiners sets whether to check the ContextJ rules as defined in Appendix
+// A of RFC 5892, concerning the use of joiner runes.
+//
+// This option corresponds to the CheckJoiners flag in UTS #46.
+func CheckJoiners(enable bool) Option {
+	return func(o *options) {
+		o.trie = trie
+		o.checkJoiners = enable
 	}
 }
 
 // StrictDomainName limits the set of permissable ASCII characters to those
 // allowed in domain names as defined in RFC 1034 (A-Z, a-z, 0-9 and the
-// hyphen). This is set by default for MapForLookup and ValidateForRegistration.
+// hyphen). This is set by default for MapForLookup and ValidateForRegistration,
+// but is only useful if ValidateLabels is set.
 //
 // This option is useful, for instance, for browsers that allow characters
 // outside this range, for example a '_' (U+005F LOW LINE). See
-// http://www.rfc-editor.org/std/std3.txt for more details This option
-// corresponds to the UseSTD3ASCIIRules option in UTS #46.
+// http://www.rfc-editor.org/std/std3.txt for more details.
+//
+// This option corresponds to the UseSTD3ASCIIRules flag in UTS #46.
 func StrictDomainName(use bool) Option {
-	return func(o *options) {
-		o.trie = trie
-		o.useSTD3Rules = use
-		o.fromPuny = validateFromPunycode
-	}
+	return func(o *options) { o.useSTD3Rules = use }
 }
 
 // NOTE: the following options pull in tables. The tables should not be linked
@@ -116,6 +140,8 @@ func StrictDomainName(use bool) Option {
 
 // BidiRule enables the Bidi rule as defined in RFC 5893. Any application
 // that relies on proper validation of labels should include this rule.
+//
+// This option corresponds to the CheckBidi flag in UTS #46.
 func BidiRule() Option {
 	return func(o *options) { o.bidirule = bidirule.ValidString }
 }
@@ -152,7 +178,8 @@ func MapForLookup() Option {
 type options struct {
 	transitional      bool
 	useSTD3Rules      bool
-	validateLabels    bool
+	checkHyphens      bool
+	checkJoiners      bool
 	verifyDNSLength   bool
 	removeLeadingDots bool
 
@@ -225,8 +252,11 @@ func (p *Profile) String() string {
 	if p.useSTD3Rules {
 		s += ":UseSTD3Rules"
 	}
-	if p.validateLabels {
-		s += ":ValidateLabels"
+	if p.checkHyphens {
+		s += ":CheckHyphens"
+	}
+	if p.checkJoiners {
+		s += ":CheckJoiners"
 	}
 	if p.verifyDNSLength {
 		s += ":VerifyDNSLength"
@@ -255,9 +285,10 @@ var (
 	punycode = &Profile{}
 	lookup   = &Profile{options{
 		transitional:      true,
-		useSTD3Rules:      true,
-		validateLabels:    true,
 		removeLeadingDots: true,
+		useSTD3Rules:      true,
+		checkHyphens:      true,
+		checkJoiners:      true,
 		trie:              trie,
 		fromPuny:          validateFromPunycode,
 		mapping:           validateAndMap,
@@ -265,8 +296,9 @@ var (
 	}}
 	display = &Profile{options{
 		useSTD3Rules:      true,
-		validateLabels:    true,
 		removeLeadingDots: true,
+		checkHyphens:      true,
+		checkJoiners:      true,
 		trie:              trie,
 		fromPuny:          validateFromPunycode,
 		mapping:           validateAndMap,
@@ -274,8 +306,9 @@ var (
 	}}
 	registration = &Profile{options{
 		useSTD3Rules:    true,
-		validateLabels:  true,
 		verifyDNSLength: true,
+		checkHyphens:    true,
+		checkJoiners:    true,
 		trie:            trie,
 		fromPuny:        validateFromPunycode,
 		mapping:         validateRegistration,
@@ -339,7 +372,7 @@ func (p *Profile) process(s string, toASCII bool) (string, error) {
 				continue
 			}
 			labels.set(u)
-			if err == nil && p.validateLabels {
+			if err == nil && p.fromPuny != nil {
 				err = p.fromPuny(p, u)
 			}
 			if err == nil {
@@ -629,16 +662,18 @@ func (p *Profile) validateLabel(s string) error {
 	if p.bidirule != nil && !p.bidirule(s) {
 		return &labelError{s, "B"}
 	}
-	if !p.validateLabels {
-		return nil
-	}
-	trie := p.trie // p.validateLabels is only set if trie is set.
-	if len(s) > 4 && s[2] == '-' && s[3] == '-' {
-		return &labelError{s, "V2"}
+	if p.checkHyphens {
+		if len(s) > 4 && s[2] == '-' && s[3] == '-' {
+			return &labelError{s, "V2"}
+		}
+		if s[0] == '-' || s[len(s)-1] == '-' {
+			return &labelError{s, "V3"}
+		}
 	}
-	if s[0] == '-' || s[len(s)-1] == '-' {
-		return &labelError{s, "V3"}
+	if !p.checkJoiners {
+		return nil
 	}
+	trie := p.trie // p.checkJoiners is only set if trie is set.
 	// TODO: merge the use of this in the trie.
 	v, sz := trie.lookupString(s)
 	x := info(v)
diff --git a/vendor/golang.org/x/net/internal/socket/mmsghdr_unix.go b/vendor/golang.org/x/net/internal/socket/mmsghdr_unix.go
index 5025a0f75..40ebedab3 100644
--- a/vendor/golang.org/x/net/internal/socket/mmsghdr_unix.go
+++ b/vendor/golang.org/x/net/internal/socket/mmsghdr_unix.go
@@ -7,25 +7,13 @@
 
 package socket
 
-import "net"
+import (
+	"net"
+	"sync"
+)
 
 type mmsghdrs []mmsghdr
 
-func (hs mmsghdrs) pack(ms []Message, parseFn func([]byte, string) (net.Addr, error), marshalFn func(net.Addr) []byte) error {
-	for i := range hs {
-		vs := make([]iovec, len(ms[i].Buffers))
-		var sa []byte
-		if parseFn != nil {
-			sa = make([]byte, sizeofSockaddrInet6)
-		}
-		if marshalFn != nil {
-			sa = marshalFn(ms[i].Addr)
-		}
-		hs[i].Hdr.pack(vs, ms[i].Buffers, ms[i].OOB, sa)
-	}
-	return nil
-}
-
 func (hs mmsghdrs) unpack(ms []Message, parseFn func([]byte, string) (net.Addr, error), hint string) error {
 	for i := range hs {
 		ms[i].N = int(hs[i].Len)
@@ -41,3 +29,86 @@ func (hs mmsghdrs) unpack(ms []Message, parseFn func([]byte, string) (net.Addr,
 	}
 	return nil
 }
+
+// mmsghdrsPacker packs Message-slices into mmsghdrs (re-)using pre-allocated buffers.
+type mmsghdrsPacker struct {
+	// hs are the pre-allocated mmsghdrs.
+	hs mmsghdrs
+	// sockaddrs is the pre-allocated buffer for the Hdr.Name buffers.
+	// We use one large buffer for all messages and slice it up.
+	sockaddrs []byte
+	// vs are the pre-allocated iovecs.
+	// We allocate one large buffer for all messages and slice it up. This allows to reuse the buffer
+	// if the number of buffers per message is distributed differently between calls.
+	vs []iovec
+}
+
+func (p *mmsghdrsPacker) prepare(ms []Message) {
+	n := len(ms)
+	if n <= cap(p.hs) {
+		p.hs = p.hs[:n]
+	} else {
+		p.hs = make(mmsghdrs, n)
+	}
+	if n*sizeofSockaddrInet6 <= cap(p.sockaddrs) {
+		p.sockaddrs = p.sockaddrs[:n*sizeofSockaddrInet6]
+	} else {
+		p.sockaddrs = make([]byte, n*sizeofSockaddrInet6)
+	}
+
+	nb := 0
+	for _, m := range ms {
+		nb += len(m.Buffers)
+	}
+	if nb <= cap(p.vs) {
+		p.vs = p.vs[:nb]
+	} else {
+		p.vs = make([]iovec, nb)
+	}
+}
+
+func (p *mmsghdrsPacker) pack(ms []Message, parseFn func([]byte, string) (net.Addr, error), marshalFn func(net.Addr, []byte) int) mmsghdrs {
+	p.prepare(ms)
+	hs := p.hs
+	vsRest := p.vs
+	saRest := p.sockaddrs
+	for i := range hs {
+		nvs := len(ms[i].Buffers)
+		vs := vsRest[:nvs]
+		vsRest = vsRest[nvs:]
+
+		var sa []byte
+		if parseFn != nil {
+			sa = saRest[:sizeofSockaddrInet6]
+			saRest = saRest[sizeofSockaddrInet6:]
+		} else if marshalFn != nil {
+			n := marshalFn(ms[i].Addr, saRest)
+			if n > 0 {
+				sa = saRest[:n]
+				saRest = saRest[n:]
+			}
+		}
+		hs[i].Hdr.pack(vs, ms[i].Buffers, ms[i].OOB, sa)
+	}
+	return hs
+}
+
+var defaultMmsghdrsPool = mmsghdrsPool{
+	p: sync.Pool{
+		New: func() interface{} {
+			return new(mmsghdrsPacker)
+		},
+	},
+}
+
+type mmsghdrsPool struct {
+	p sync.Pool
+}
+
+func (p *mmsghdrsPool) Get() *mmsghdrsPacker {
+	return p.p.Get().(*mmsghdrsPacker)
+}
+
+func (p *mmsghdrsPool) Put(packer *mmsghdrsPacker) {
+	p.p.Put(packer)
+}
diff --git a/vendor/golang.org/x/net/internal/socket/msghdr_linux.go b/vendor/golang.org/x/net/internal/socket/msghdr_linux.go
index 5a38798cc..c3c7cc4c8 100644
--- a/vendor/golang.org/x/net/internal/socket/msghdr_linux.go
+++ b/vendor/golang.org/x/net/internal/socket/msghdr_linux.go
@@ -17,6 +17,9 @@ func (h *msghdr) pack(vs []iovec, bs [][]byte, oob []byte, sa []byte) {
 	if sa != nil {
 		h.Name = (*byte)(unsafe.Pointer(&sa[0]))
 		h.Namelen = uint32(len(sa))
+	} else {
+		h.Name = nil
+		h.Namelen = 0
 	}
 }
 
diff --git a/vendor/golang.org/x/net/internal/socket/rawconn_mmsg.go b/vendor/golang.org/x/net/internal/socket/rawconn_mmsg.go
index 5d90de118..d80a15c6b 100644
--- a/vendor/golang.org/x/net/internal/socket/rawconn_mmsg.go
+++ b/vendor/golang.org/x/net/internal/socket/rawconn_mmsg.go
@@ -17,14 +17,13 @@ func (c *Conn) recvMsgs(ms []Message, flags int) (int, error) {
 	for i := range ms {
 		ms[i].raceWrite()
 	}
-	hs := make(mmsghdrs, len(ms))
+	packer := defaultMmsghdrsPool.Get()
+	defer defaultMmsghdrsPool.Put(packer)
 	var parseFn func([]byte, string) (net.Addr, error)
 	if c.network != "tcp" {
 		parseFn = parseInetAddr
 	}
-	if err := hs.pack(ms, parseFn, nil); err != nil {
-		return 0, err
-	}
+	hs := packer.pack(ms, parseFn, nil)
 	var operr error
 	var n int
 	fn := func(s uintptr) bool {
@@ -50,14 +49,13 @@ func (c *Conn) sendMsgs(ms []Message, flags int) (int, error) {
 	for i := range ms {
 		ms[i].raceRead()
 	}
-	hs := make(mmsghdrs, len(ms))
-	var marshalFn func(net.Addr) []byte
+	packer := defaultMmsghdrsPool.Get()
+	defer defaultMmsghdrsPool.Put(packer)
+	var marshalFn func(net.Addr, []byte) int
 	if c.network != "tcp" {
 		marshalFn = marshalInetAddr
 	}
-	if err := hs.pack(ms, nil, marshalFn); err != nil {
-		return 0, err
-	}
+	hs := packer.pack(ms, nil, marshalFn)
 	var operr error
 	var n int
 	fn := func(s uintptr) bool {
diff --git a/vendor/golang.org/x/net/internal/socket/rawconn_msg.go b/vendor/golang.org/x/net/internal/socket/rawconn_msg.go
index dfed9a8da..2e2d61b76 100644
--- a/vendor/golang.org/x/net/internal/socket/rawconn_msg.go
+++ b/vendor/golang.org/x/net/internal/socket/rawconn_msg.go
@@ -55,7 +55,9 @@ func (c *Conn) sendMsg(m *Message, flags int) error {
 	vs := make([]iovec, len(m.Buffers))
 	var sa []byte
 	if m.Addr != nil {
-		sa = marshalInetAddr(m.Addr)
+		var a [sizeofSockaddrInet6]byte
+		n := marshalInetAddr(m.Addr, a[:])
+		sa = a[:n]
 	}
 	h.pack(vs, m.Buffers, m.OOB, sa)
 	var operr error
diff --git a/vendor/golang.org/x/net/internal/socket/sys_posix.go b/vendor/golang.org/x/net/internal/socket/sys_posix.go
index d8dda77b5..42b8f2340 100644
--- a/vendor/golang.org/x/net/internal/socket/sys_posix.go
+++ b/vendor/golang.org/x/net/internal/socket/sys_posix.go
@@ -17,22 +17,24 @@ import (
 	"time"
 )
 
-func marshalInetAddr(a net.Addr) []byte {
+// marshalInetAddr writes a in sockaddr format into the buffer b.
+// The buffer must be sufficiently large (sizeofSockaddrInet4/6).
+// Returns the number of bytes written.
+func marshalInetAddr(a net.Addr, b []byte) int {
 	switch a := a.(type) {
 	case *net.TCPAddr:
-		return marshalSockaddr(a.IP, a.Port, a.Zone)
+		return marshalSockaddr(a.IP, a.Port, a.Zone, b)
 	case *net.UDPAddr:
-		return marshalSockaddr(a.IP, a.Port, a.Zone)
+		return marshalSockaddr(a.IP, a.Port, a.Zone, b)
 	case *net.IPAddr:
-		return marshalSockaddr(a.IP, 0, a.Zone)
+		return marshalSockaddr(a.IP, 0, a.Zone, b)
 	default:
-		return nil
+		return 0
 	}
 }
 
-func marshalSockaddr(ip net.IP, port int, zone string) []byte {
+func marshalSockaddr(ip net.IP, port int, zone string, b []byte) int {
 	if ip4 := ip.To4(); ip4 != nil {
-		b := make([]byte, sizeofSockaddrInet4)
 		switch runtime.GOOS {
 		case "android", "illumos", "linux", "solaris", "windows":
 			NativeEndian.PutUint16(b[:2], uint16(sysAF_INET))
@@ -42,10 +44,9 @@ func marshalSockaddr(ip net.IP, port int, zone string) []byte {
 		}
 		binary.BigEndian.PutUint16(b[2:4], uint16(port))
 		copy(b[4:8], ip4)
-		return b
+		return sizeofSockaddrInet4
 	}
 	if ip6 := ip.To16(); ip6 != nil && ip.To4() == nil {
-		b := make([]byte, sizeofSockaddrInet6)
 		switch runtime.GOOS {
 		case "android", "illumos", "linux", "solaris", "windows":
 			NativeEndian.PutUint16(b[:2], uint16(sysAF_INET6))
@@ -58,9 +59,9 @@ func marshalSockaddr(ip net.IP, port int, zone string) []byte {
 		if zone != "" {
 			NativeEndian.PutUint32(b[24:28], uint32(zoneCache.index(zone)))
 		}
-		return b
+		return sizeofSockaddrInet6
 	}
-	return nil
+	return 0
 }
 
 func parseInetAddr(b []byte, network string) (net.Addr, error) {
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 010b0f5bd..b14d4e7a4 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -163,7 +163,8 @@ golang.org/x/crypto/ssh/terminal
 # golang.org/x/mod v0.4.2
 ## explicit
 golang.org/x/mod/semver
-# golang.org/x/net v0.0.0-20210428140749-89ef3d95e781
+# golang.org/x/net v0.0.0-20210520170846-37e1c6afe023
+## explicit
 golang.org/x/net/bpf
 golang.org/x/net/context
 golang.org/x/net/context/ctxhttp