net/http: set Request.TLS when net.Conn implements ConnectionState

Fixes #56104

Change-Id: I8fbbb00379e51323e2782144070cbcad650eb6f1
GitHub-Last-Rev: 62d7a8064e4f2173f0d8e02ed91a7e8de7f13fca
GitHub-Pull-Request: golang/go#56110
Reviewed-on: https://go-review.googlesource.com/c/go/+/440795
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Sean Liao <sean@liao.dev>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

src/net/http/serve_test.go

@@ -1645,6 +1645,53 @@ func testTLSServer(t *testing.T, mode testMode) {
 	}
 }
 
+type fakeConnectionStateConn struct {
+	net.Conn
+}
+
+func (fcsc *fakeConnectionStateConn) ConnectionState() tls.ConnectionState {
+	return tls.ConnectionState{
+		ServerName: "example.com",
+	}
+}
+
+func TestTLSServerWithoutTLSConn(t *testing.T) {
+	//set up
+	pr, pw := net.Pipe()
+	c := make(chan int)
+	listener := &oneConnListener{&fakeConnectionStateConn{pr}}
+	server := &Server{
+		Handler: HandlerFunc(func(writer ResponseWriter, request *Request) {
+			if request.TLS == nil {
+				t.Fatal("request.TLS is nil, expected not nil")
+			}
+			if request.TLS.ServerName != "example.com" {
+				t.Fatalf("request.TLS.ServerName is %s, expected %s", request.TLS.ServerName, "example.com")
+			}
+			writer.Header().Set("X-TLS-ServerName", "example.com")
+		}),
+	}
+
+	// write request and read response
+	go func() {
+		req, _ := NewRequest(MethodGet, "https://example.com", nil)
+		req.Write(pw)
+
+		resp, _ := ReadResponse(bufio.NewReader(pw), req)
+		if hdr := resp.Header.Get("X-TLS-ServerName"); hdr != "example.com" {
+			t.Errorf("response header X-TLS-ServerName is %s, expected %s", hdr, "example.com")
+		}
+		close(c)
+		pw.Close()
+	}()
+
+	server.Serve(listener)
+
+	// oneConnListener returns error after one accept, wait util response is read
+	<-c
+	pr.Close()
+}
+
 func TestServeTLS(t *testing.T) {
 	CondSkipHTTP2(t)
 	// Not parallel: uses global test hooks.

src/net/http/server.go

@@ -1924,6 +1924,10 @@ func isCommonNetReadError(err error) bool {
 	return false
 }
 
+type connectionStater interface {
+	ConnectionState() tls.ConnectionState
+}
+
 // Serve a new connection.
 func (c *conn) serve(ctx context.Context) {
 	if ra := c.rwc.RemoteAddr(); ra != nil {
@@ -1996,6 +2000,14 @@ func (c *conn) serve(ctx context.Context) {
 
 	// HTTP/1.x from here on.
 
+	// Set Request.TLS if the conn is not a *tls.Conn, but implements ConnectionState.
+	if c.tlsState == nil {
+		if tc, ok := c.rwc.(connectionStater); ok {
+			c.tlsState = new(tls.ConnectionState)
+			*c.tlsState = tc.ConnectionState()
+		}
+	}
+
 	ctx, cancelCtx := context.WithCancel(ctx)
 	c.cancelCtx = cancelCtx
 	defer cancelCtx()