tunnel: deduplicate addresses from config

Windows doesn't like it when passing these off to its config.

Reported-by: Jonathan Tooker <jonathan.tooker@netprotect.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

2 files changed, 44 insertions, 0 deletions

diff --git a/conf/config.go b/conf/config.go
index 5b3496b6..a84dc418 100644
--- a/conf/config.go
+++ b/conf/config.go
@@ -196,3 +196,46 @@ func (b Bytes) String() string {
 	}
 	return fmt.Sprintf("%.2f TiB", float64(b)/(1024*1024*1024)/1024)
 }
+
+func (conf *Config) DeduplicateNetworkEntries() {
+	m := make(map[string]bool, len(conf.Interface.Addresses))
+	i := 0
+	for _, addr := range conf.Interface.Addresses {
+		s := addr.String()
+		if m[s] {
+			continue
+		}
+		m[s] = true
+		conf.Interface.Addresses[i] = addr
+		i++
+	}
+	conf.Interface.Addresses = conf.Interface.Addresses[:i]
+
+	m = make(map[string]bool, len(conf.Interface.DNS))
+	i = 0
+	for _, addr := range conf.Interface.DNS {
+		s := addr.String()
+		if m[s] {
+			continue
+		}
+		m[s] = true
+		conf.Interface.DNS[i] = addr
+		i++
+	}
+	conf.Interface.DNS = conf.Interface.DNS[:i]
+
+	for _, peer := range conf.Peers {
+		m = make(map[string]bool, len(peer.AllowedIPs))
+		i = 0
+		for _, addr := range peer.AllowedIPs {
+			s := addr.String()
+			if m[s] {
+				continue
+			}
+			m[s] = true
+			peer.AllowedIPs[i] = addr
+			i++
+		}
+		peer.AllowedIPs = peer.AllowedIPs[:i]
+	}
+}
diff --git a/tunnel/service.go b/tunnel/service.go
index 8bd981d6..e535894b 100644
--- a/tunnel/service.go
+++ b/tunnel/service.go
@@ -118,6 +118,7 @@ func (service *tunnelService) Execute(args []string, r <-chan svc.ChangeRequest,
 		serviceError = services.ErrorLoadConfiguration
 		return
 	}
+	conf.DeduplicateNetworkEntries()
 	err = CopyConfigOwnerToIPCSecurityDescriptor(service.Path)
 	if err != nil {
 		serviceError = services.ErrorLoadConfiguration