blob: 15f37b22c99123b22cb70b0a8605aa39f81b6d9a [file] [log] [blame]
From d5293038e8f979ecc872bdf9b28af2cec7f55e07 Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nico@fluxnic.net>
Date: Tue, 5 Nov 2019 10:33:16 +0100
Subject: [PATCH] vcs: prevent write access to vcsu devices
commit 0c9acb1af77a3cb8707e43f45b72c95266903cee upstream.
Commit d21b0be246bf ("vt: introduce unicode mode for /dev/vcs") guarded
against using devices containing attributes as this is not yet
implemented. It however failed to guard against writes to any devices
as this is also unimplemented.
Reported-by: Or Cohen <orcohen@paloaltonetworks.com>
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Cc: <stable@vger.kernel.org> # v4.19+
Cc: Jiri Slaby <jslaby@suse.com>
Fixes: d21b0be246bf ("vt: introduce unicode mode for /dev/vcs")
Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.1911051030580.30289@knanqh.ubzr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
index 1f042346e722..778f83ea2249 100644
--- a/drivers/tty/vt/vc_screen.c
+++ b/drivers/tty/vt/vc_screen.c
@@ -456,6 +456,9 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
size_t ret;
char *con_buf;
+ if (use_unicode(inode))
+ return -EOPNOTSUPP;
+
con_buf = (char *) __get_free_page(GFP_KERNEL);
if (!con_buf)
return -ENOMEM;
--
2.7.4