From e9fe69045bd648d75d8d8099b8658a4ee005a8e5 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 21 Jan 2014 15:48:13 -0800 Subject: [PATCH] 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 Reviewed-by: Christoph Hellwig Cc: Eric Paris Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/notify/inotify/inotify_user.c | 41 ++++++++++++++++---------------- 1 file changed, 21 insertions(+), 20 deletions(-) diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index 60f954a891ab..1bb6dc8eaf1c 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -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); -- GitLab