1 files changed, 31 insertions, 27 deletions

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 2bb4dfc02873..57fc6ee12332 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -235,7 +235,6 @@ static void tty_del_file(struct file *file)
 /**
  *	tty_name	-	return tty naming
  *	@tty: tty structure
- *	@buf: buffer for output
  *
  *	Convert a tty structure into a name. The name reflects the kernel
  *	naming policy and if udev is in use may not reflect user space
@@ -243,13 +242,11 @@ static void tty_del_file(struct file *file)
  *	Locking: none
  */
 
-char *tty_name(struct tty_struct *tty, char *buf)
+const char *tty_name(const struct tty_struct *tty)
 {
 	if (!tty) /* Hmm.  NULL pointer.  That's fun. */
-		strcpy(buf, "NULL tty");
-	else
-		strcpy(buf, tty->name);
-	return buf;
+		return "NULL tty";
+	return tty->name;
 }
 
 EXPORT_SYMBOL(tty_name);
@@ -770,8 +767,7 @@ static void do_tty_hangup(struct work_struct *work)
 void tty_hangup(struct tty_struct *tty)
 {
 #ifdef TTY_DEBUG_HANGUP
-	char	buf[64];
-	printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
+	printk(KERN_DEBUG "%s hangup...\n", tty_name(tty));
 #endif
 	schedule_work(&tty->hangup_work);
 }
@@ -790,9 +786,7 @@ EXPORT_SYMBOL(tty_hangup);
 void tty_vhangup(struct tty_struct *tty)
 {
 #ifdef TTY_DEBUG_HANGUP
-	char	buf[64];
-
-	printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
+	printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty));
 #endif
 	__tty_hangup(tty, 0);
 }
@@ -831,9 +825,7 @@ void tty_vhangup_self(void)
 static void tty_vhangup_session(struct tty_struct *tty)
 {
 #ifdef TTY_DEBUG_HANGUP
-	char	buf[64];
-
-	printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty, buf));
+	printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty));
 #endif
 	__tty_hangup(tty, 1);
 }
@@ -1025,11 +1017,17 @@ void start_tty(struct tty_struct *tty)
 }
 EXPORT_SYMBOL(start_tty);
 
-/* We limit tty time update visibility to every 8 seconds or so. */
 static void tty_update_time(struct timespec *time)
 {
 	unsigned long sec = get_seconds();
-	if (abs(sec - time->tv_sec) & ~7)
+
+	/*
+	 * We only care if the two values differ in anything other than the
+	 * lower three bits (i.e every 8 seconds).  If so, then we can update
+	 * the time of the tty device, otherwise it could be construded as a
+	 * security leak to let userspace know the exact timing of the tty.
+	 */
+	if ((sec ^ time->tv_sec) & ~7)
 		time->tv_sec = sec;
 }
 
@@ -1763,7 +1761,6 @@ int tty_release(struct inode *inode, struct file *filp)
 	struct tty_struct *o_tty = NULL;
 	int	do_sleep, final;
 	int	idx;
-	char	buf[64];
 	long	timeout = 0;
 	int	once = 1;
 
@@ -1787,7 +1784,7 @@ int tty_release(struct inode *inode, struct file *filp)
 
 #ifdef TTY_DEBUG_HANGUP
 	printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
-			tty_name(tty, buf), tty->count);
+			tty_name(tty), tty->count);
 #endif
 
 	if (tty->ops->close)
@@ -1838,7 +1835,7 @@ int tty_release(struct inode *inode, struct file *filp)
 		if (once) {
 			once = 0;
 			printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
-			       __func__, tty_name(tty, buf));
+			       __func__, tty_name(tty));
 		}
 		schedule_timeout_killable(timeout);
 		if (timeout < 120 * HZ)
@@ -1850,13 +1847,13 @@ int tty_release(struct inode *inode, struct file *filp)
 	if (o_tty) {
 		if (--o_tty->count < 0) {
 			printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
-				__func__, o_tty->count, tty_name(o_tty, buf));
+				__func__, o_tty->count, tty_name(o_tty));
 			o_tty->count = 0;
 		}
 	}
 	if (--tty->count < 0) {
 		printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
-				__func__, tty->count, tty_name(tty, buf));
+				__func__, tty->count, tty_name(tty));
 		tty->count = 0;
 	}
 
@@ -1899,7 +1896,7 @@ int tty_release(struct inode *inode, struct file *filp)
 		return 0;
 
 #ifdef TTY_DEBUG_HANGUP
-	printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
+	printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty));
 #endif
 	/*
 	 * Ask the line discipline code to release its structures
@@ -1910,7 +1907,8 @@ int tty_release(struct inode *inode, struct file *filp)
 	tty_flush_works(tty);
 
 #ifdef TTY_DEBUG_HANGUP
-	printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
+	printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__,
+	       tty_name(tty));
 #endif
 	/*
 	 * The release_tty function takes care of the details of clearing
@@ -3593,6 +3591,13 @@ static ssize_t show_cons_active(struct device *dev,
 }
 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
 
+static struct attribute *cons_dev_attrs[] = {
+	&dev_attr_active.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(cons_dev);
+
 static struct device *consdev;
 
 void console_sysfs_notify(void)
@@ -3617,12 +3622,11 @@ int __init tty_init(void)
 	if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
 	    register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
 		panic("Couldn't register /dev/console driver\n");
-	consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
-			      "console");
+	consdev = device_create_with_groups(tty_class, NULL,
+					    MKDEV(TTYAUX_MAJOR, 1), NULL,
+					    cons_dev_groups, "console");
 	if (IS_ERR(consdev))
 		consdev = NULL;
-	else
-		WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
 
 #ifdef CONFIG_VT
 	vty_init(&console_fops);