[PATCH openEuler-22.03-LTS] tty: n_gsm: require CAP_NET_ADMIN to attach N_GSM0710 ldisc - Kernel

26 Aug 2024

From: Thadeu Lima de Souza Cascardo cascardo@canonical.com
stable inclusion
from stable-v5.10.215
commit ada28eb4b9561aab93942f3224a2e41d76fe57fa
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=...
--------------------------------
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 6cd87e71fecc..96a5e0f91c15 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2619,6 +2619,9 @@ 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;
-- 
2.34.1


    