1 files changed, 13 insertions, 1 deletions
diff --git a/vendor/k8s.io/apimachinery/pkg/util/httpstream/httpstream.go b/vendor/k8s.io/apimachinery/pkg/util/httpstream/httpstream.go
index 9d5fdeece..00ce5f785 100644
--- a/vendor/k8s.io/apimachinery/pkg/util/httpstream/httpstream.go
+++ b/vendor/k8s.io/apimachinery/pkg/util/httpstream/httpstream.go
@@ -114,6 +114,18 @@ func negotiateProtocol(clientProtocols, serverProtocols []string) string {
 	return ""
 }
 
+func commaSeparatedHeaderValues(header []string) []string {
+	var parsedClientProtocols []string
+	for i := range header {
+		for _, clientProtocol := range strings.Split(header[i], ",") {
+			if proto := strings.Trim(clientProtocol, " "); len(proto) > 0 {
+				parsedClientProtocols = append(parsedClientProtocols, proto)
+			}
+		}
+	}
+	return parsedClientProtocols
+}
+
 // Handshake performs a subprotocol negotiation. If the client did request a
 // subprotocol, Handshake will select the first common value found in
 // serverProtocols. If a match is found, Handshake adds a response header
@@ -121,7 +133,7 @@ func negotiateProtocol(clientProtocols, serverProtocols []string) string {
 // returned, along with a response header containing the list of protocols the
 // server can accept.
 func Handshake(req *http.Request, w http.ResponseWriter, serverProtocols []string) (string, error) {
-	clientProtocols := req.Header[http.CanonicalHeaderKey(HeaderProtocolVersion)]
+	clientProtocols := commaSeparatedHeaderValues(req.Header[http.CanonicalHeaderKey(HeaderProtocolVersion)])
 	if len(clientProtocols) == 0 {
 		return "", fmt.Errorf("unable to upgrade: %s is required", HeaderProtocolVersion)
 	}