[Devel] [PATCH RH8 2/2] tty/vt: check allocation size in con_set_unimap()

[Evgenii Shatokhin]

From: Denis Efremov <efremov at linux.com>

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);
 
-- 
2.29.0