2020-06-03 10:28:45

by Denis Efremov (Oracle)

Subject: [PATCH] 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.

Cc: Kees Cook <[email protected]>
Signed-off-by: Denis Efremov <[email protected]>
---
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);

--
2.26.2

2020-06-03 19:19:13

by Kees Cook

Subject: Re: [PATCH] tty/vt: check allocation size in con_set_unimap()

On Wed, Jun 03, 2020 at 01:28:04PM +0300, Denis Efremov wrote:
> The vmemdup_user() function has no 2-factor argument form. Use array_size()
> to check for the overflow.
>
> Cc: Kees Cook <[email protected]>
> Signed-off-by: Denis Efremov <[email protected]>

Reviewed-by: Kees Cook <[email protected]>

--
Kees Cook