net/http: don't write body for HEAD responses in Response.Write

Fixes #62015

Change-Id: I88c5427f85e740d5b956942bb1c2727dac2935ea
Reviewed-on: https://go-review.googlesource.com/c/go/+/601238
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

2 files changed, 143 insertions, 6 deletions

diff --git a/src/net/http/response_test.go b/src/net/http/response_test.go
index a63aac95ac..3ccbb9b0f2 100644
--- a/src/net/http/response_test.go
+++ b/src/net/http/response_test.go
@@ -21,9 +21,10 @@ import (
 )
 
 type respTest struct {
-	Raw  string
-	Resp Response
-	Body string
+	Raw    string
+	RawOut string
+	Resp   Response
+	Body   string
 }
 
 func dummyReq(method string) *Request {
@@ -42,6 +43,11 @@ var respTests = []respTest{
 			"\r\n" +
 			"Body here\n",
 
+		"HTTP/1.0 200 OK\r\n" +
+			"Connection: close\r\n" +
+			"\r\n" +
+			"Body here\n",
+
 		Response{
 			Status:     "200 OK",
 			StatusCode: 200,
@@ -66,6 +72,11 @@ var respTests = []respTest{
 			"\r\n" +
 			"Body here\n",
 
+		"HTTP/1.1 200 OK\r\n" +
+			"Connection: close\r\n" +
+			"\r\n" +
+			"Body here\n",
+
 		Response{
 			Status:        "200 OK",
 			StatusCode:    200,
@@ -87,6 +98,9 @@ var respTests = []respTest{
 			"\r\n" +
 			"Body should not be read!\n",
 
+		"HTTP/1.1 204 No Content\r\n" +
+			"\r\n",
+
 		Response{
 			Status:        "204 No Content",
 			StatusCode:    204,
@@ -110,6 +124,12 @@ var respTests = []respTest{
 			"\r\n" +
 			"Body here\n",
 
+		"HTTP/1.0 200 OK\r\n" +
+			"Content-Length: 10\r\n" +
+			"Connection: close\r\n" +
+			"\r\n" +
+			"Body here\n",
+
 		Response{
 			Status:     "200 OK",
 			StatusCode: 200,
@@ -140,6 +160,14 @@ var respTests = []respTest{
 			"0\r\n" +
 			"\r\n",
 
+		"HTTP/1.1 200 OK\r\n" +
+			"Transfer-Encoding: chunked\r\n" +
+			"\r\n" +
+			"13\r\n" +
+			"Body here\ncontinued\r\n" +
+			"0\r\n" +
+			"\r\n",
+
 		Response{
 			Status:           "200 OK",
 			StatusCode:       200,
@@ -165,6 +193,12 @@ var respTests = []respTest{
 			"\r\n" +
 			"Body here\n",
 
+		"HTTP/1.0 200 OK\r\n" +
+			"Content-Length: 10\r\n" +
+			"Connection: close\r\n" +
+			"\r\n" +
+			"Body here\n",
+
 		Response{
 			Status:     "200 OK",
 			StatusCode: 200,
@@ -195,6 +229,14 @@ var respTests = []respTest{
 			"0\r\n" +
 			"\r\n",
 
+		"HTTP/1.1 200 OK\r\n" +
+			"Transfer-Encoding: chunked\r\n" +
+			"\r\n" +
+			"a\r\n" +
+			"Body here\n\r\n" +
+			"0\r\n" +
+			"\r\n",
+
 		Response{
 			Status:           "200 OK",
 			StatusCode:       200,
@@ -217,6 +259,10 @@ var respTests = []respTest{
 			"Transfer-Encoding: chunked\r\n" +
 			"\r\n",
 
+		"HTTP/1.1 200 OK\r\n" +
+			"Transfer-Encoding: chunked\r\n" +
+			"\r\n",
+
 		Response{
 			Status:           "200 OK",
 			StatusCode:       200,
@@ -239,6 +285,11 @@ var respTests = []respTest{
 			"Content-Length: 256\r\n" +
 			"\r\n",
 
+		"HTTP/1.0 200 OK\r\n" +
+			"Connection: close\r\n" +
+			"Content-Length: 256\r\n" +
+			"\r\n",
+
 		Response{
 			Status:           "200 OK",
 			StatusCode:       200,
@@ -261,6 +312,10 @@ var respTests = []respTest{
 			"Content-Length: 256\r\n" +
 			"\r\n",
 
+		"HTTP/1.1 200 OK\r\n" +
+			"Content-Length: 256\r\n" +
+			"\r\n",
+
 		Response{
 			Status:           "200 OK",
 			StatusCode:       200,
@@ -282,6 +337,10 @@ var respTests = []respTest{
 		"HTTP/1.0 200 OK\r\n" +
 			"\r\n",
 
+		"HTTP/1.0 200 OK\r\n" +
+			"Connection: close\r\n" +
+			"\r\n",
+
 		Response{
 			Status:           "200 OK",
 			StatusCode:       200,
@@ -304,6 +363,10 @@ var respTests = []respTest{
 			"Content-Length: 0\r\n" +
 			"\r\n",
 
+		"HTTP/1.1 200 OK\r\n" +
+			"Content-Length: 0\r\n" +
+			"\r\n",
+
 		Response{
 			Status:     "200 OK",
 			StatusCode: 200,
@@ -325,6 +388,11 @@ var respTests = []respTest{
 	// (permitted by RFC 7230, section 3.1.2)
 	{
 		"HTTP/1.0 303 \r\n\r\n",
+
+		"HTTP/1.0 303 \r\n" +
+			"Connection: close\r\n" +
+			"\r\n",
+
 		Response{
 			Status:        "303 ",
 			StatusCode:    303,
@@ -344,6 +412,11 @@ var respTests = []respTest{
 	// (not permitted by RFC 7230, but we'll accept it anyway)
 	{
 		"HTTP/1.0 303\r\n\r\n",
+
+		"HTTP/1.0 303 303\r\n" +
+			"Connection: close\r\n" +
+			"\r\n",
+
 		Response{
 			Status:        "303",
 			StatusCode:    303,
@@ -366,6 +439,13 @@ Connection: close
 Content-Type: multipart/byteranges; boundary=18a75608c8f47cef
 
 some body`,
+
+		"HTTP/1.1 206 Partial Content\r\n" +
+			"Connection: close\r\n" +
+			"Content-Type: multipart/byteranges; boundary=18a75608c8f47cef\r\n" +
+			"\r\n" +
+			"some body",
+
 		Response{
 			Status:     "206 Partial Content",
 			StatusCode: 206,
@@ -390,6 +470,11 @@ some body`,
 			"\r\n" +
 			"Body here\n",
 
+		"HTTP/1.0 200 OK\r\n" +
+			"Connection: close\r\n" +
+			"\r\n" +
+			"Body here\n",
+
 		Response{
 			Status:     "200 OK",
 			StatusCode: 200,
@@ -415,6 +500,14 @@ some body`,
 			"Content-Length: 6\r\n\r\n" +
 			"foobar",
 
+		"HTTP/1.1 206 Partial Content\r\n" +
+			"Content-Length: 6\r\n" +
+			"Accept-Ranges: bytes\r\n" +
+			"Content-Range: bytes 0-5/1862\r\n" +
+			"Content-Type: text/plain; charset=utf-8\r\n" +
+			"\r\n" +
+			"foobar",
+
 		Response{
 			Status:     "206 Partial Content",
 			StatusCode: 206,
@@ -441,6 +534,11 @@ some body`,
 			"Connection: keep-alive, close\r\n" +
 			"\r\n",
 
+		"HTTP/1.1 200 OK\r\n" +
+			"Connection: close\r\n" +
+			"Content-Length: 256\r\n" +
+			"\r\n",
+
 		Response{
 			Status:     "200 OK",
 			StatusCode: 200,
@@ -467,6 +565,11 @@ some body`,
 			"Connection: close\r\n" +
 			"\r\n",
 
+		"HTTP/1.1 200 OK\r\n" +
+			"Connection: close\r\n" +
+			"Content-Length: 256\r\n" +
+			"\r\n",
+
 		Response{
 			Status:     "200 OK",
 			StatusCode: 200,
@@ -493,6 +596,11 @@ some body`,
 			"\r\n" +
 			"Body here\n",
 
+		"HTTP/1.0 200 OK\r\n" +
+			"Connection: close\r\n" +
+			"\r\n" +
+			"Body here\n",
+
 		Response{
 			Status:        "200 OK",
 			StatusCode:    200,
@@ -517,6 +625,12 @@ some body`,
 			"\r\n" +
 			"Body here\n",
 
+		"HTTP/1.0 200 OK\r\n" +
+			"Connection: close\r\n" +
+			"Content-Length: 10\r\n" +
+			"\r\n" +
+			"Body here\n",
+
 		Response{
 			Status:     "200 OK",
 			StatusCode: 200,
@@ -541,6 +655,14 @@ some body`,
 			"Connection: keep-alive\r\n" +
 			"Keep-Alive: timeout=7200\r\n\r\n" +
 			"\x1f\x8b\b\x00\x00\x00\x00\x00\x00\x00s\xf3\xf7\a\x00\xab'\xd4\x1a\x03\x00\x00\x00",
+
+		"HTTP/1.1 200 OK\r\n" +
+			"Content-Length: 23\r\n" +
+			"Connection: keep-alive\r\n" +
+			"Content-Encoding: gzip\r\n" +
+			"Keep-Alive: timeout=7200\r\n\r\n" +
+			"\x1f\x8b\b\x00\x00\x00\x00\x00\x00\x00s\xf3\xf7\a\x00\xab'\xd4\x1a\x03\x00\x00\x00",
+
 		Response{
 			Status:     "200 OK",
 			StatusCode: 200,
@@ -566,6 +688,14 @@ some body`,
 			"Content-type: text/html\r\n" +
 			"WWW-Authenticate: Basic realm=\"\"\r\n\r\n" +
 			"Your Authentication failed.\r\n",
+
+		"HTTP/1.0 401 Unauthorized\r\n" +
+			"Connection: close\r\n" +
+			"Content-Type: text/html\r\n" +
+			"Www-Authenticate: Basic realm=\"\"\r\n" +
+			"\r\n" +
+			"Your Authentication failed.\r\n",
+
 		Response{
 			Status:     "401 Unauthorized",
 			StatusCode: 401,
@@ -619,11 +749,18 @@ func TestWriteResponse(t *testing.T) {
 			t.Errorf("#%d: %v", i, err)
 			continue
 		}
-		err = resp.Write(io.Discard)
+		var buf bytes.Buffer
+		err = resp.Write(&buf)
 		if err != nil {
 			t.Errorf("#%d: %v", i, err)
 			continue
 		}
+		if got, want := buf.String(), tt.RawOut; got != want {
+			t.Errorf("#%d: response differs; got:\n----\n%v\n----\nwant:\n----\n%v\n----\n",
+				i,
+				strings.ReplaceAll(got, "\r", "\\r"),
+				strings.ReplaceAll(want, "\r", "\\r"))
+		}
 	}
 }
 
diff --git a/src/net/http/transfer.go b/src/net/http/transfer.go
index 5a3c6ceff5..f7eef6475e 100644
--- a/src/net/http/transfer.go
+++ b/src/net/http/transfer.go
@@ -350,7 +350,7 @@ func (t *transferWriter) writeBody(w io.Writer) (err error) {
 	// nopCloser or readTrackingBody. This is to ensure that we can take advantage of
 	// OS-level optimizations in the event that the body is an
 	// *os.File.
-	if t.Body != nil {
+	if !t.ResponseToHEAD && t.Body != nil {
 		var body = t.unwrapBody()
 		if chunked(t.TransferEncoding) {
 			if bw, ok := w.(*bufio.Writer); ok && !t.IsResponse {
@@ -392,7 +392,7 @@ func (t *transferWriter) writeBody(w io.Writer) (err error) {
 			t.ContentLength, ncopy)
 	}
 
-	if chunked(t.TransferEncoding) {
+	if !t.ResponseToHEAD && chunked(t.TransferEncoding) {
 		// Write Trailer header
 		if t.Trailer != nil {
 			if err := t.Trailer.Write(w); err != nil {