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Commit e9fe6904 authored by Jan Kara's avatar Jan Kara Committed by Linus Torvalds
Browse files

inotify: provide function for name length rounding 



Rounding of name length when passing it to userspace was done in several
places.  Provide a function to do it and use it in all places.

Signed-off-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0abdd7a8

fs/notify/inotify/inotify_user.c

+21 −20
Original line number Diff line number Diff line
@@ -124,6 +124,13 @@ static unsigned int inotify_poll(struct file *file, poll_table *wait) 
	return ret;

}



static int round_event_name_len(struct fsnotify_event *event)

{

	if (!event->name_len)

		return 0;

	return roundup(event->name_len + 1, sizeof(struct inotify_event));

}



/*

 * Get an inotify_kernel_event if one exists and is small

 * enough to fit in "count". Return an error pointer if
@@ -144,9 +151,7 @@ static struct fsnotify_event *get_one_event(struct fsnotify_group *group, 


	pr_debug("%s: group=%p event=%p\n", __func__, group, event);



	if (event->name_len)

		event_size += roundup(event->name_len + 1, event_size);



	event_size += round_event_name_len(event);

	if (event_size > count)

		return ERR_PTR(-EINVAL);
@@ -171,7 +176,8 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, 
	struct fsnotify_event_private_data *fsn_priv;

	struct inotify_event_private_data *priv;

	size_t event_size = sizeof(struct inotify_event);

	size_t name_len = 0;

	size_t name_len;

	size_t pad_name_len;



	pr_debug("%s: group=%p event=%p\n", __func__, group, event);
@@ -189,14 +195,13 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, 
		inotify_free_event_priv(fsn_priv);

	}



	name_len = event->name_len;

	/*

	 * round up event->name_len so it is a multiple of event_size

	 * round up name length so it is a multiple of event_size

	 * plus an extra byte for the terminating '\0'.

	 */

	if (event->name_len)

		name_len = roundup(event->name_len + 1, event_size);

	inotify_event.len = name_len;



	pad_name_len = round_event_name_len(event);

	inotify_event.len = pad_name_len;

	inotify_event.mask = inotify_mask_to_arg(event->mask);

	inotify_event.cookie = event->sync_cookie;
@@ -209,20 +214,18 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, 
	/*

	 * fsnotify only stores the pathname, so here we have to send the pathname

	 * and then pad that pathname out to a multiple of sizeof(inotify_event)

	 * with zeros.  I get my zeros from the nul_inotify_event.

	 * with zeros.

	 */

	if (name_len) {

		unsigned int len_to_zero = name_len - event->name_len;

	if (pad_name_len) {

		/* copy the path name */

		if (copy_to_user(buf, event->file_name, event->name_len))

		if (copy_to_user(buf, event->file_name, name_len))

			return -EFAULT;

		buf += event->name_len;

		buf += name_len;



		/* fill userspace with 0's */

		if (clear_user(buf, len_to_zero))

		if (clear_user(buf, pad_name_len - name_len))

			return -EFAULT;

		buf += len_to_zero;

		event_size += name_len;

		event_size += pad_name_len;

	}



	return event_size;
@@ -314,9 +317,7 @@ static long inotify_ioctl(struct file *file, unsigned int cmd, 
		list_for_each_entry(holder, &group->notification_list, event_list) {

			event = holder->event;

			send_len += sizeof(struct inotify_event);

			if (event->name_len)

				send_len += roundup(event->name_len + 1,

						sizeof(struct inotify_event));

			send_len += round_event_name_len(event);

		}

		mutex_unlock(&group->notification_mutex);

		ret = put_user(send_len, (int __user *) p);