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fix: use crypto/rand instead of math/rand #291

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Merged
merged 1 commit into from
Feb 23, 2025
Merged

fix: use crypto/rand instead of math/rand #291

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31 changes: 23 additions & 8 deletions internal/dns/dns.go
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
// Copyright 2024 Blink Labs Software
// Copyright 2025 Blink Labs Software
//
// Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file or at
Expand All @@ -9,7 +9,8 @@ package dns
import (
"fmt"
"log/slog"
"math/rand"
"crypto/rand"
"math/big"
"net"
"os"
"strings"
Expand Down Expand Up @@ -326,7 +327,11 @@ func randomNameserverAddress(nameservers map[string][]net.IP) net.IP {
tmpNameservers = append(tmpNameservers, addresses...)
}
if len(tmpNameservers) > 0 {
tmpNameserver := tmpNameservers[rand.Intn(len(tmpNameservers))]
n, err := rand.Int(rand.Reader, big.NewInt(int64(len(tmpNameservers))))
if err != nil {
return nil
}
tmpNameserver := tmpNameservers[n.Int64()]
return tmpNameserver
}
return nil
Expand Down Expand Up @@ -511,12 +516,20 @@ func randomNameserver(nameservers map[string][]net.IP) (string, string) {
mapKeys = append(mapKeys, k)
}
if len(mapKeys) > 0 {
randNsName := mapKeys[rand.Intn(len(mapKeys))]
n, err := rand.Int(rand.Reader, big.NewInt(int64(len(mapKeys))))
if err != nil {
return "", ""
}
randNsName := mapKeys[n.Int64()]
randNsAddresses := nameservers[randNsName]
if randNsAddresses == nil {
return "", ""
}
randNsAddress := randNsAddresses[rand.Intn(len(randNsAddresses))].String()
n, err = rand.Int(rand.Reader, big.NewInt(int64(len(randNsAddresses))))
if err != nil {
return "", ""
}
randNsAddress := randNsAddresses[n.Int64()].String()
return randNsName, randNsAddress
}
return "", ""
Expand All @@ -531,9 +544,11 @@ func createQuery(recordName string, recordType uint16) *dns.Msg {

func randomFallbackServer() string {
cfg := config.GetConfig()
return cfg.Dns.FallbackServers[rand.Intn(
len(cfg.Dns.FallbackServers),
)]
n, err := rand.Int(rand.Reader, big.NewInt(int64(len(cfg.Dns.FallbackServers))))
if err != nil {
return ""
}
return cfg.Dns.FallbackServers[n.Int64()]
}

func formatMessageAnswerSection(section []dns.RR) string {
Expand Down