firewall: use random GUIDs

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/tunnel/firewall/helpers.go b/tunnel/firewall/helpers.go
index ee783c2d..79ab0d82 100644
--- a/tunnel/firewall/helpers.go
+++ b/tunnel/firewall/helpers.go
@@ -7,10 +7,12 @@ package firewall
 
 import (
 	"fmt"
+	"io"
 	"os"
 	"runtime"
 	"syscall"
 	"unsafe"
+	"crypto/rand"
 
 	"golang.org/x/sys/windows"
 )
@@ -135,3 +137,15 @@ func getCurrentProcessAppID() (*wtFwpByteBlob, error) {
 	}
 	return appID, nil
 }
+
+func randGUID() (windows.GUID, error) {
+	guid := windows.GUID{}
+	n, err := rand.Read((*[16]byte)(unsafe.Pointer(&guid))[:])
+	if err != nil {
+		return guid, err
+	}
+	if n != 16 {
+		return guid, io.ErrShortBuffer
+	}
+	return guid, nil
+}
\ No newline at end of file