[PATCH 36/36] tty/vt: consolemap: walk the buffer only once in con_set_trans_old()

Jiri Slaby
2022-06-07T10:53:07Z

Fetch the user data one by one (by get_user()) and fill in the local
buffer simultaneously. I.e. we no longer require to walk two buffers and
save thus 256 B from stack (whole ubuf).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/tty/vt/consolemap.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index f97f7ee6268b..fff97ae87e00 100644
--- a/drivers/tty/vt/consolemap.c
+++ b/drivers/tty/vt/consolemap.c
@@ -343,15 +343,15 @@ static void update_user_maps(void)
*/
int con_set_trans_old(unsigned char __user * arg)
{
- int i;
unsigned short inbuf[E_TABSZ];
- unsigned char ubuf[E_TABSZ];
-
- if (copy_from_user(ubuf, arg, E_TABSZ))
- return -EFAULT;
+ unsigned int i;
+ unsigned char ch;

- for (i = 0; i < E_TABSZ ; i++)
- inbuf[i] = UNI_DIRECT_BASE | ubuf[i];
+ for (i = 0; i < ARRAY_SIZE(inbuf); i++) {
+ if (get_user(ch, &arg[i]))
+ return -EFAULT;
+ inbuf[i] = UNI_DIRECT_BASE | ch;
+ }

console_lock();
memcpy(translations[USER_MAP], inbuf, sizeof(inbuf));
--
2.36.1