Proxy: add basic authentication middleware (#500)

* Proxy: add basic authentication middleware

* Proxy: fix ok

cmd/proxy/actions/basicauth.go

@@ -0,0 +1,41 @@
+package actions
+
+import (
+	"crypto/subtle"
+	"net/http"
+
+	"github.com/gobuffalo/buffalo"
+)
+
+func basicAuth(user, pass string) buffalo.MiddlewareFunc {
+	return func(next buffalo.Handler) buffalo.Handler {
+		return func(c buffalo.Context) error {
+			if !checkAuth(c.Request(), user, pass) {
+				c.Response().Header().Set("WWW-Authenticate", `Basic realm="basic auth required"`)
+				c.Render(401, nil)
+				return nil
+			}
+
+			return next(c)
+		}
+	}
+}
+
+func checkAuth(r *http.Request, user, pass string) bool {
+	givenUser, givenPass, ok := r.BasicAuth()
+	if !ok {
+		return false
+	}
+
+	isUser := subtle.ConstantTimeCompare([]byte(user), []byte(givenUser))
+	if isUser != 1 {
+		return false
+	}
+
+	isPass := subtle.ConstantTimeCompare([]byte(pass), []byte(givenPass))
+	if isPass != 1 {
+		return false
+	}
+
+	return true
+}