blob: 0467aefcd562439db93890299f10fce9b5d85088 [file] [log] [blame]
From 8b9547069d6987c8e2e681471f65d09fd545f933 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Mon, 24 Feb 2020 00:03:26 -0800
Subject: [PATCH] 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>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index 38948ac5fc49..7297997fcf04 100644
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -350,22 +350,13 @@ int vt_ioctl(struct tty_struct *tty,
{
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.
@@ -1195,14 +1186,9 @@ long vt_compat_ioctl(struct tty_struct *tty,
{
struct vc_data *vc = tty->driver_data;
struct console_font_op op; /* used in multiple places here */
- unsigned int console = vc->vc_num;
void __user *up = compat_ptr(arg);
int perm;
-
- if (!vc_cons_allocated(console)) /* impossible? */
- return -ENOIOCTLCMD;
-
/*
* 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.
--
2.7.4