diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 457f2d7430cf13684f6ac4c5c971530d029d8b46..15d67635bb10540ee1185818aaa2b83c86bbee5b 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -123,7 +123,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file)
 
 	/* Check permissions */
 	if (((tun->owner != -1 && cred->euid != tun->owner) ||
-	     (tun->group != -1 && cred->egid != tun->group)) &&
+	     (tun->group != -1 && !in_egroup_p(tun->group))) &&
 		!capable(CAP_NET_ADMIN))
 		return -EPERM;