vt: vt_ioctl: remove unnecessary console allocation checks
commit 1aa6e058dd6cd04471b1f21298270014daf48ac9 upstream.
The vc_cons_allocated() checks in vt_ioctl() and vt_compat_ioctl() are
unnecessary because they can only be reached by calling ioctl() on an
open tty, which implies the corresponding virtual console is allocated.
And even if the virtual console *could* be freed concurrently, then
these checks would be broken since they aren't done under console_lock,
and the vc_data is dereferenced before them anyway.
So, remove these unneeded checks to avoid confusion.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200224080326.295046-1-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index c0057ad..7d3248f 100644
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -353,22 +353,13 @@
{
struct vc_data *vc = tty->driver_data;
struct console_font_op op; /* used in multiple places here */
- unsigned int console;
+ unsigned int console = vc->vc_num;
unsigned char ucval;
unsigned int uival;
void __user *up = (void __user *)arg;
int i, perm;
int ret = 0;
- console = vc->vc_num;
-
-
- if (!vc_cons_allocated(console)) { /* impossible? */
- ret = -ENOIOCTLCMD;
- goto out;
- }
-
-
/*
* To have permissions to do most of the vt ioctls, we either have
* to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
@@ -1202,18 +1193,10 @@
{
struct vc_data *vc = tty->driver_data;
struct console_font_op op; /* used in multiple places here */
- unsigned int console;
void __user *up = (void __user *)arg;
int perm;
int ret = 0;
- console = vc->vc_num;
-
- if (!vc_cons_allocated(console)) { /* impossible? */
- ret = -ENOIOCTLCMD;
- goto out;
- }
-
/*
* To have permissions to do most of the vt ioctls, we either have
* to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
@@ -1273,7 +1256,7 @@
arg = (unsigned long)compat_ptr(arg);
goto fallback;
}
-out:
+
return ret;
fallback: