4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thadeu Lima de Souza Cascardo cascardo@canonical.com
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@canonical.com Link: https://lore.kernel.org/r/20230731185942.279611-1-cascardo@canonical.com From: Salvatore Bonaccorso carnil@debian.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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;