[PATCH 14/17] vt: keyboard, union perm checks in vt_do_kdgkb_ioctl

From: Jiri Slaby
Date: Thu Oct 29 2020 - 07:33:21 EST


Do the permission check on a single place. That is where perm is
really checked.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/tty/vt/keyboard.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index 648bdfb05e25..1de0d5217aed 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -2040,9 +2040,6 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm)
char *kbs;
int ret;

- if (!capable(CAP_SYS_TTY_CONFIG))
- perm = 0;
-
if (get_user(kb_func, &user_kdgkb->kb_func))
return -EFAULT;

@@ -2067,7 +2064,7 @@ int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm)
break;
}
case KDSKBSENT:
- if (!perm)
+ if (!perm || !capable(CAP_SYS_TTY_CONFIG))
return -EPERM;

kbs = strndup_user(user_kdgkb->kb_string,
--
2.29.1