vcs: prevent write access to vcsu devices

Commit d21b0be246 ("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: d21b0be246 ("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>
This commit is contained in:
Nicolas Pitre 2019-11-05 10:33:16 +01:00 committed by Greg Kroah-Hartman
parent b2b2dd71e0
commit 0c9acb1af7

View File

@ -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;