validate: allow unset "type" fields in resource devices whitelist

According to the spec, an unset .Type field in the
.Linux.Resources.Devices list is permitted (and it maps to "all").
This was broken recently, making our own default profile (as well as
umoci's and runc's) not pass validation anymore.

Signed-off-by: Aleksa Sarai <asarai@suse.de>

Author: cyphar

validate/validate.go

@@ -749,7 +749,7 @@ func (v *Validator) CheckLinuxResources() (errs error) {
 	}
 	for index := 0; index < len(r.Devices); index++ {
 		switch r.Devices[index].Type {
-		case "a", "b", "c":
+		case "a", "b", "c", "":
 		default:
 			errs = multierror.Append(errs, fmt.Errorf("type of devices %s is invalid", r.Devices[index].Type))
 		}