From: Thadeu Lima de Souza Cascardo cascardo@canonical.com

stable inclusion from stable-v4.19.315 commit 7d303dee473ba3529d75b63491e9963342107bed category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9S26U CVE: CVE-2023-52880

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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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 Cc: Salvatore Bonaccorso carnil@debian.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Xiang Yang xiangyang3@huawei.com --- 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 05d9064b4ee7..10ccad12c92b 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2356,6 +2356,9 @@ static int gsmld_open(struct tty_struct *tty) struct gsm_mux *gsm; int ret;

+ if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (tty->ops->write == NULL) return -EINVAL;