policy: Do not return an error for invalid value during parsing (#9442)

s3:HardwareInfo was removed recently. Users having that admin action
stored in the backend will have an issue starting the server.

To fix this, we need to avoid returning an error in Marshal/Unmarshal
when they encounter an invalid action and validate only in specific
location.

Currently the validation is done and in ParseConfig().

pkg/iam/policy/actionset.go

@@ -107,6 +107,16 @@ func (actionSet ActionSet) ToSlice() []Action {
 	return actions
 }
 
+// ToAdminSlice - returns slice of admin actions from the action set.
+func (actionSet ActionSet) ToAdminSlice() []AdminAction {
+	actions := []AdminAction{}
+	for action := range actionSet {
+		actions = append(actions, AdminAction(action))
+	}
+
+	return actions
+}
+
 // UnmarshalJSON - decodes JSON data to ActionSet.
 func (actionSet *ActionSet) UnmarshalJSON(data []byte) error {
 	var sset set.StringSet
@@ -120,17 +130,32 @@ func (actionSet *ActionSet) UnmarshalJSON(data []byte) error {
 
 	*actionSet = make(ActionSet)
 	for _, s := range sset.ToSlice() {
-		action, err := parseAction(s)
-		if err != nil {
-			return err
-		}
-
-		actionSet.Add(action)
+		actionSet.Add(Action(s))
 	}
 
 	return nil
 }
 
+// ValidateAdmin checks if all actions are valid Admin actions
+func (actionSet ActionSet) ValidateAdmin() error {
+	for _, action := range actionSet.ToAdminSlice() {
+		if !action.IsValid() {
+			return Errorf("unsupported admin action '%v'", action)
+		}
+	}
+	return nil
+}
+
+// Validate checks if all actions are valid
+func (actionSet ActionSet) Validate() error {
+	for _, action := range actionSet.ToSlice() {
+		if !action.IsValid() {
+			return Errorf("unsupported action '%v'", action)
+		}
+	}
+	return nil
+}
+
 // NewActionSet - creates new action set.
 func NewActionSet(actions ...Action) ActionSet {
 	actionSet := make(ActionSet)