4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx> commit 67c37756898a5a6b2941a13ae7260c89b54e0d88 upstream. 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 <cascardo@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230731185942.279611-1-cascardo@xxxxxxxxxxxxx From: Salvatore Bonaccorso <carnil@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/n_gsm.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2435,6 +2435,9 @@ static int gsmld_open(struct tty_struct struct gsm_mux *gsm; int ret; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (tty->ops->write == NULL) return -EINVAL;
