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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: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jan Kara 2014-01-21 15:48:13 -08:00 committed by Linus Torvalds
parent 0abdd7a81b
commit e9fe69045b
1 changed files with 21 additions and 20 deletions
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41
fs/notify/inotify/inotify_user.c
View File

@ -124,6 +124,13 @@ static unsigned int inotify_poll(struct file *file, poll_table *wait)
return ret; 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 * Get an inotify_kernel_event if one exists and is small
* enough to fit in "count". Return an error pointer if * 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); pr_debug("%s: group=%p event=%p\n", __func__, group, event);
if (event->name_len) event_size += round_event_name_len(event);
event_size += roundup(event->name_len + 1, event_size);
if (event_size > count) if (event_size > count)
return ERR_PTR(-EINVAL); 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 fsnotify_event_private_data *fsn_priv;
struct inotify_event_private_data *priv; struct inotify_event_private_data *priv;
size_t event_size = sizeof(struct inotify_event); 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); 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); 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'. * plus an extra byte for the terminating '\0'.
*/ */
if (event->name_len) pad_name_len = round_event_name_len(event);
name_len = roundup(event->name_len + 1, event_size); inotify_event.len = pad_name_len;
inotify_event.len = name_len;
inotify_event.mask = inotify_mask_to_arg(event->mask); inotify_event.mask = inotify_mask_to_arg(event->mask);
inotify_event.cookie = event->sync_cookie; 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 * 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) * 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) { if (pad_name_len) {
unsigned int len_to_zero = name_len - event->name_len;
/* copy the path name */ /* 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; return -EFAULT;
buf += event->name_len; buf += name_len;
/* fill userspace with 0's */ /* fill userspace with 0's */
if (clear_user(buf, len_to_zero)) if (clear_user(buf, pad_name_len - name_len))
return -EFAULT; return -EFAULT;
buf += len_to_zero; event_size += pad_name_len;
event_size += name_len;
} }
return event_size; 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) { list_for_each_entry(holder, &group->notification_list, event_list) {
event = holder->event; event = holder->event;
send_len += sizeof(struct inotify_event); send_len += sizeof(struct inotify_event);
if (event->name_len) send_len += round_event_name_len(event);
send_len += roundup(event->name_len + 1,
sizeof(struct inotify_event));
} }
mutex_unlock(&group->notification_mutex); mutex_unlock(&group->notification_mutex);
ret = put_user(send_len, (int __user *) p); ret = put_user(send_len, (int __user *) p);