dnsx/alg,dnscrypt: m mutex for a thread-safe map

Author: ignoramous

intra/dnscrypt/servers.go

@@ -19,6 +19,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"maps"
 	"math/rand"
 	"net"
 	"net/netip"
@@ -178,7 +179,14 @@ func (serversInfo *ServersInfo) refresh(proxy *DcMulti) ([]string, error) {
 	}
 	var liveServers []string
 	var err error
-	for _, registeredServer := range serversInfo.registeredServers {
+
+	// Get a snapshot of registered servers under lock to prevent race conditions
+	serversInfo.RLock()
+	copied := make(map[string]registeredserver)
+	maps.Copy(copied, serversInfo.registeredServers)
+	serversInfo.RUnlock()
+
+	for _, registeredServer := range copied {
 		if err = serversInfo.refreshServer(proxy, registeredServer.name, registeredServer.stamp); err == nil {
 			liveServers = append(liveServers, registeredServer.name)
 		} else {

intra/dnsx/alg.go

@@ -258,6 +258,8 @@ func (p *xips) String() string {
 	if p == nil {
 		return "<nil>"
 	}
+	p.pmu.RLock()
+	defer p.pmu.RUnlock()
 	return fmt.Sprintf("xips: pri(%v) sec(%v)", p.pri, p.aux)
 }
 
@@ -1922,7 +1924,7 @@ func Req(t Transport, network string, q *dns.Msg, smm *x.DNSSummary) (*dns.Msg,
 	}
 
 	if settings.Debug {
-		log.V("alg: Req: %s:%d servfail; by: %s, rdata: %d, status: %d, rcode %d",
+		log.V("alg: Req: %s:%d servfail; by: %s, rdata: %s, status: %d, rcode %d",
 			qname, qtyp, smm.ID, smm.RData, smm.Status, xdns.Rcode(r))
 	}
 	return r, err