do not allow preauth keys to be deleted if assigned to node (#2396)

* do not allow preauth keys to be deleted if assigned to node

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

* update changelog

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

---------

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

hscontrol/types/node.go

@@ -77,9 +77,12 @@ type Node struct {
 
 	ForcedTags []string `gorm:"serializer:json"`
 
-	// TODO(kradalby): This seems like irrelevant information?
-	AuthKeyID *uint64     `sql:"DEFAULT:NULL"`
-	AuthKey   *PreAuthKey `gorm:"constraint:OnDelete:SET NULL;"`
+	// When a node has been created with a PreAuthKey, we need to
+	// prevent the preauthkey from being deleted before the node.
+	// The preauthkey can define "tags" of the node so we need it
+	// around.
+	AuthKeyID *uint64 `sql:"DEFAULT:NULL"`
+	AuthKey   *PreAuthKey
 
 	LastSeen *time.Time
 	Expiry   *time.Time

hscontrol/types/preauth_key.go

@@ -14,7 +14,7 @@ type PreAuthKey struct {
 	ID        uint64 `gorm:"primary_key"`
 	Key       string
 	UserID    uint
-	User      User `gorm:"constraint:OnDelete:CASCADE;"`
+	User      User `gorm:"constraint:OnDelete:SET NULL;"`
 	Reusable  bool
 	Ephemeral bool     `gorm:"default:false"`
 	Used      bool     `gorm:"default:false"`