[Devel] [PATCH RHEL8 COMMIT] tty/vt: check allocation size in con_set_unimap()

[Konstantin Khorenko]

The commit is pushed to "branch-rh8-4.18.0-240.1.1.vz8.5.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-240.1.1.vz8.5.43
------>
commit 7f30a5255d380e892badfc32b2daa7826e117028
Author: Denis Efremov <efremov at linux.com>
Date:   Wed Jun 16 10:11:57 2021 +0300

    tty/vt: check allocation size in con_set_unimap()
    
    The vmemdup_user() function has no 2-factor argument form. Use array_size()
    to check for the overflow.
    
    Signed-off-by: Denis Efremov <efremov at linux.com>
    Reviewed-by: Kees Cook <keescook at chromium.org>
    Link: https://lore.kernel.org/r/20200603102804.2110817-1-efremov@linux.com
    Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
    
    Commit 5de30b286e7166164f9e45de991bde26f5db8298 in the mainline kernel.
    It is a follow-up for ms commit fa2b360f261e "tty/vt: avoid high order pages
    allocation on GIO_UNIMAP ioctl" and is nice to have in VZ8 too.
    
    Added to VZ8 in the scope of https://jira.sw.ru/browse/PSBM-127844.
    Signed-off-by: Evgenii Shatokhin <eshatokhin at virtuozzo.com>
---
 drivers/tty/vt/consolemap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index b28aa0d289f8..32acea9e8270 100644
--- a/drivers/tty/vt/consolemap.c
+++ b/drivers/tty/vt/consolemap.c
@@ -542,7 +542,7 @@ int con_set_unimap(struct vc_data *vc, ushort ct, struct unipair __user *list)
 	if (!ct)
 		return 0;
 
-	unilist = vmemdup_user(list, ct * sizeof(struct unipair));
+	unilist = vmemdup_user(list, array_size(sizeof(struct unipair), ct));
 	if (IS_ERR(unilist))
 		return PTR_ERR(unilist);