From 67c37756898a5a6b2941a13ae7260c89b54e0d88 Mon Sep 17 00:00:00 2001 From: Thadeu Lima de Souza Cascardo Date: Mon, 31 Jul 2023 15:59:42 -0300 Subject: [PATCH] tty: n_gsm: require CAP_NET_ADMIN to attach N_GSM0710 ldisc Any unprivileged user can attach N_GSM0710 ldisc, but it requires CAP_NET_ADMIN to create a GSM network anyway. Require initial namespace CAP_NET_ADMIN to do that. Signed-off-by: Thadeu Lima de Souza Cascardo Link: https://lore.kernel.org/r/20230731185942.279611-1-cascardo@canonical.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 1cdefac4dd1b..c7a787f10a9c 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -3576,6 +3576,9 @@ static int gsmld_open(struct tty_struct *tty) { struct gsm_mux *gsm; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (tty->ops->write == NULL) return -EINVAL;