Use cloneMsg instead of shallow Copy for cached DNS messages

jedisct1 · jedisct1 · commit 8775802be5e6 · 2026-07-10T12:15:52.000+02:00
miekg/dns/v2 Msg.Copy() only does a useless shallow copy of the RR
slices, so use cloneMsg instead.
diff --git a/dnscrypt-proxy/plugin_cache.go b/dnscrypt-proxy/plugin_cache.go
@@ -79,7 +79,7 @@ func (plugin *PluginCache) Eval(pluginsState *PluginsState, msg *dns.Msg) error
 		return nil
 	}
 	expiration := cached.expiration
-	synth := cached.msg.Copy()
+	synth := cloneMsg(cached.msg)
 
 	synth.ID = msg.ID
 	synth.Response = true
@@ -141,7 +141,7 @@ func (plugin *PluginCacheResponse) Eval(pluginsState *PluginsState, msg *dns.Msg
 	)
 	cachedResponse := CachedResponse{
 		expiration: time.Now().Add(ttl),
-		msg:        msg.Copy(),
+		msg:        cloneMsg(msg),
 	}
 	var cacheInitError error
 	cachedResponses.cacheOnce.Do(func() {

Original file line number	Diff line number	Diff line change
`@@ -79,7 +79,7 @@ func (plugin PluginCache) Eval(pluginsState PluginsState, msg *dns.Msg) error`
`79`	`79`	`return nil`
`80`	`80`	`}`
`81`	`81`	`expiration := cached.expiration`
`82`		`- synth := cached.msg.Copy()`
	`82`	`+ synth := cloneMsg(cached.msg)`
`83`	`83`
`84`	`84`	`synth.ID = msg.ID`
`85`	`85`	`synth.Response = true`
`@@ -141,7 +141,7 @@ func (plugin PluginCacheResponse) Eval(pluginsState PluginsState, msg *dns.Msg`
`141`	`141`	`)`
`142`	`142`	`cachedResponse := CachedResponse{`
`143`	`143`	`expiration: time.Now().Add(ttl),`
`144`		`- msg: msg.Copy(),`
	`144`	`+ msg: cloneMsg(msg),`
`145`	`145`	`}`
`146`	`146`	`var cacheInitError error`
`147`	`147`	`cachedResponses.cacheOnce.Do(func() {`