From a7ad0034453ba4c353f9b8f810ee2569de33d283 Mon Sep 17 00:00:00 2001 From: Joshua Rogers Date: Fri, 31 Jul 2026 09:56:17 +0200 Subject: [PATCH] vt: add permission check for KDSKBMETA ioctl KDSKBMETA modifies keyboard meta mode but lacks the !perm check that all other keyboard setter ioctls in vt_k_ioctl() enforce, allowing a process to change meta mode on a non-controlling console without authorization. Assisted-by: AISLE:Snapshot Cc: stable Signed-off-by: Joshua Rogers Link: https://patch.msgid.link/20260731-tty-vt-stuff-v1-2-be99b9da8e30@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt_ioctl.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c index 28993a3d0acb..deb3b3f93461 100644 --- a/drivers/tty/vt/vt_ioctl.c +++ b/drivers/tty/vt/vt_ioctl.c @@ -406,6 +406,8 @@ static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd, /* this could be folded into KDSKBMODE, but for compatibility reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */ case KDSKBMETA: + if (!perm) + return -EPERM; return vt_do_kdskbmeta(console, arg); case KDGKBMETA: