![Eric Paris](/assets/img/avatar_default.png)
fanotify currently has no limit on the number of listeners a given user can have open. This patch limits the total number of listeners per user to 128. This is the same as the inotify default limit. Signed-off-by: Eric Paris <eparis@redhat.com>
860 lines
21 KiB
C
860 lines
21 KiB
C
#include <linux/fanotify.h>
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#include <linux/fcntl.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/anon_inodes.h>
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#include <linux/fsnotify_backend.h>
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#include <linux/init.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/poll.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include <asm/ioctls.h>
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#define FANOTIFY_DEFAULT_MAX_EVENTS 16384
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#define FANOTIFY_DEFAULT_MAX_MARKS 8192
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#define FANOTIFY_DEFAULT_MAX_LISTENERS 128
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extern const struct fsnotify_ops fanotify_fsnotify_ops;
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static struct kmem_cache *fanotify_mark_cache __read_mostly;
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static struct kmem_cache *fanotify_response_event_cache __read_mostly;
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struct fanotify_response_event {
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struct list_head list;
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__s32 fd;
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struct fsnotify_event *event;
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};
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/*
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* Get an fsnotify notification event if one exists and is small
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* enough to fit in "count". Return an error pointer if the count
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* is not large enough.
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*
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* Called with the group->notification_mutex held.
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*/
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static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
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size_t count)
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{
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BUG_ON(!mutex_is_locked(&group->notification_mutex));
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pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
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if (fsnotify_notify_queue_is_empty(group))
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return NULL;
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if (FAN_EVENT_METADATA_LEN > count)
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return ERR_PTR(-EINVAL);
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/* held the notification_mutex the whole time, so this is the
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* same event we peeked above */
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return fsnotify_remove_notify_event(group);
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}
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static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
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{
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int client_fd;
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struct dentry *dentry;
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struct vfsmount *mnt;
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struct file *new_file;
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pr_debug("%s: group=%p event=%p\n", __func__, group, event);
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client_fd = get_unused_fd();
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if (client_fd < 0)
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return client_fd;
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if (event->data_type != FSNOTIFY_EVENT_PATH) {
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WARN_ON(1);
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put_unused_fd(client_fd);
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return -EINVAL;
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}
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/*
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* we need a new file handle for the userspace program so it can read even if it was
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* originally opened O_WRONLY.
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*/
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dentry = dget(event->path.dentry);
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mnt = mntget(event->path.mnt);
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/* it's possible this event was an overflow event. in that case dentry and mnt
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* are NULL; That's fine, just don't call dentry open */
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if (dentry && mnt)
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new_file = dentry_open(dentry, mnt,
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group->fanotify_data.f_flags | FMODE_NONOTIFY,
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current_cred());
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else
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new_file = ERR_PTR(-EOVERFLOW);
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if (IS_ERR(new_file)) {
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/*
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* we still send an event even if we can't open the file. this
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* can happen when say tasks are gone and we try to open their
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* /proc files or we try to open a WRONLY file like in sysfs
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* we just send the errno to userspace since there isn't much
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* else we can do.
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*/
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put_unused_fd(client_fd);
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client_fd = PTR_ERR(new_file);
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} else {
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fd_install(client_fd, new_file);
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}
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return client_fd;
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}
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static ssize_t fill_event_metadata(struct fsnotify_group *group,
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struct fanotify_event_metadata *metadata,
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struct fsnotify_event *event)
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{
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pr_debug("%s: group=%p metadata=%p event=%p\n", __func__,
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group, metadata, event);
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metadata->event_len = FAN_EVENT_METADATA_LEN;
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metadata->vers = FANOTIFY_METADATA_VERSION;
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metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS;
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metadata->pid = pid_vnr(event->tgid);
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metadata->fd = create_fd(group, event);
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return metadata->fd;
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}
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#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
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static struct fanotify_response_event *dequeue_re(struct fsnotify_group *group,
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__s32 fd)
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{
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struct fanotify_response_event *re, *return_re = NULL;
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mutex_lock(&group->fanotify_data.access_mutex);
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list_for_each_entry(re, &group->fanotify_data.access_list, list) {
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if (re->fd != fd)
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continue;
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list_del_init(&re->list);
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return_re = re;
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break;
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}
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mutex_unlock(&group->fanotify_data.access_mutex);
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pr_debug("%s: found return_re=%p\n", __func__, return_re);
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return return_re;
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}
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static int process_access_response(struct fsnotify_group *group,
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struct fanotify_response *response_struct)
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{
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struct fanotify_response_event *re;
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__s32 fd = response_struct->fd;
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__u32 response = response_struct->response;
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pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group,
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fd, response);
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/*
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* make sure the response is valid, if invalid we do nothing and either
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* userspace can send a valid responce or we will clean it up after the
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* timeout
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*/
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switch (response) {
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case FAN_ALLOW:
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case FAN_DENY:
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break;
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default:
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return -EINVAL;
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}
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if (fd < 0)
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return -EINVAL;
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re = dequeue_re(group, fd);
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if (!re)
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return -ENOENT;
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re->event->response = response;
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wake_up(&group->fanotify_data.access_waitq);
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kmem_cache_free(fanotify_response_event_cache, re);
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return 0;
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}
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static int prepare_for_access_response(struct fsnotify_group *group,
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struct fsnotify_event *event,
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__s32 fd)
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{
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struct fanotify_response_event *re;
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if (!(event->mask & FAN_ALL_PERM_EVENTS))
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return 0;
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re = kmem_cache_alloc(fanotify_response_event_cache, GFP_KERNEL);
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if (!re)
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return -ENOMEM;
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re->event = event;
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re->fd = fd;
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mutex_lock(&group->fanotify_data.access_mutex);
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if (group->fanotify_data.bypass_perm) {
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mutex_unlock(&group->fanotify_data.access_mutex);
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kmem_cache_free(fanotify_response_event_cache, re);
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event->response = FAN_ALLOW;
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return 0;
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}
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list_add_tail(&re->list, &group->fanotify_data.access_list);
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mutex_unlock(&group->fanotify_data.access_mutex);
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return 0;
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}
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static void remove_access_response(struct fsnotify_group *group,
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struct fsnotify_event *event,
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__s32 fd)
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{
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struct fanotify_response_event *re;
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if (!(event->mask & FAN_ALL_PERM_EVENTS))
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return;
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re = dequeue_re(group, fd);
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if (!re)
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return;
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BUG_ON(re->event != event);
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kmem_cache_free(fanotify_response_event_cache, re);
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return;
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}
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#else
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static int prepare_for_access_response(struct fsnotify_group *group,
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struct fsnotify_event *event,
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__s32 fd)
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{
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return 0;
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}
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static void remove_access_response(struct fsnotify_group *group,
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struct fsnotify_event *event,
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__s32 fd)
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{
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return;
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}
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#endif
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static ssize_t copy_event_to_user(struct fsnotify_group *group,
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struct fsnotify_event *event,
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char __user *buf)
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{
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struct fanotify_event_metadata fanotify_event_metadata;
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int fd, ret;
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pr_debug("%s: group=%p event=%p\n", __func__, group, event);
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fd = fill_event_metadata(group, &fanotify_event_metadata, event);
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if (fd < 0)
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return fd;
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ret = prepare_for_access_response(group, event, fd);
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if (ret)
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goto out_close_fd;
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ret = -EFAULT;
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if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN))
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goto out_kill_access_response;
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return FAN_EVENT_METADATA_LEN;
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out_kill_access_response:
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remove_access_response(group, event, fd);
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out_close_fd:
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sys_close(fd);
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return ret;
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}
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/* intofiy userspace file descriptor functions */
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static unsigned int fanotify_poll(struct file *file, poll_table *wait)
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{
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struct fsnotify_group *group = file->private_data;
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int ret = 0;
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poll_wait(file, &group->notification_waitq, wait);
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mutex_lock(&group->notification_mutex);
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if (!fsnotify_notify_queue_is_empty(group))
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ret = POLLIN | POLLRDNORM;
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mutex_unlock(&group->notification_mutex);
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return ret;
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}
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static ssize_t fanotify_read(struct file *file, char __user *buf,
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size_t count, loff_t *pos)
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{
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struct fsnotify_group *group;
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struct fsnotify_event *kevent;
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char __user *start;
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int ret;
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DEFINE_WAIT(wait);
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start = buf;
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group = file->private_data;
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pr_debug("%s: group=%p\n", __func__, group);
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while (1) {
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prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE);
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mutex_lock(&group->notification_mutex);
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kevent = get_one_event(group, count);
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mutex_unlock(&group->notification_mutex);
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if (kevent) {
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ret = PTR_ERR(kevent);
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if (IS_ERR(kevent))
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break;
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ret = copy_event_to_user(group, kevent, buf);
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fsnotify_put_event(kevent);
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if (ret < 0)
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break;
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buf += ret;
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count -= ret;
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continue;
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}
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ret = -EAGAIN;
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if (file->f_flags & O_NONBLOCK)
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break;
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ret = -EINTR;
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if (signal_pending(current))
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break;
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if (start != buf)
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break;
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schedule();
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}
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finish_wait(&group->notification_waitq, &wait);
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if (start != buf && ret != -EFAULT)
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ret = buf - start;
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return ret;
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}
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static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
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{
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#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
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struct fanotify_response response = { .fd = -1, .response = -1 };
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struct fsnotify_group *group;
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int ret;
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group = file->private_data;
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if (count > sizeof(response))
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count = sizeof(response);
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pr_debug("%s: group=%p count=%zu\n", __func__, group, count);
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if (copy_from_user(&response, buf, count))
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return -EFAULT;
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ret = process_access_response(group, &response);
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if (ret < 0)
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count = ret;
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return count;
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#else
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return -EINVAL;
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#endif
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}
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static int fanotify_release(struct inode *ignored, struct file *file)
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{
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struct fsnotify_group *group = file->private_data;
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struct fanotify_response_event *re, *lre;
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pr_debug("%s: file=%p group=%p\n", __func__, file, group);
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#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
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mutex_lock(&group->fanotify_data.access_mutex);
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group->fanotify_data.bypass_perm = true;
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list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) {
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pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group,
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re, re->event);
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list_del_init(&re->list);
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re->event->response = FAN_ALLOW;
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kmem_cache_free(fanotify_response_event_cache, re);
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}
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mutex_unlock(&group->fanotify_data.access_mutex);
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wake_up(&group->fanotify_data.access_waitq);
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#endif
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/* matches the fanotify_init->fsnotify_alloc_group */
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fsnotify_put_group(group);
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return 0;
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}
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static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct fsnotify_group *group;
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struct fsnotify_event_holder *holder;
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void __user *p;
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int ret = -ENOTTY;
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size_t send_len = 0;
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group = file->private_data;
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p = (void __user *) arg;
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switch (cmd) {
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case FIONREAD:
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mutex_lock(&group->notification_mutex);
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list_for_each_entry(holder, &group->notification_list, event_list)
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send_len += FAN_EVENT_METADATA_LEN;
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mutex_unlock(&group->notification_mutex);
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ret = put_user(send_len, (int __user *) p);
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break;
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}
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return ret;
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}
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static const struct file_operations fanotify_fops = {
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.poll = fanotify_poll,
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.read = fanotify_read,
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.write = fanotify_write,
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.fasync = NULL,
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.release = fanotify_release,
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.unlocked_ioctl = fanotify_ioctl,
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.compat_ioctl = fanotify_ioctl,
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.llseek = noop_llseek,
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};
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static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)
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{
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kmem_cache_free(fanotify_mark_cache, fsn_mark);
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}
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static int fanotify_find_path(int dfd, const char __user *filename,
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struct path *path, unsigned int flags)
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{
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int ret;
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pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__,
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dfd, filename, flags);
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if (filename == NULL) {
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struct file *file;
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int fput_needed;
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ret = -EBADF;
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file = fget_light(dfd, &fput_needed);
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if (!file)
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goto out;
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ret = -ENOTDIR;
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if ((flags & FAN_MARK_ONLYDIR) &&
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!(S_ISDIR(file->f_path.dentry->d_inode->i_mode))) {
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fput_light(file, fput_needed);
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goto out;
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}
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*path = file->f_path;
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path_get(path);
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fput_light(file, fput_needed);
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} else {
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unsigned int lookup_flags = 0;
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if (!(flags & FAN_MARK_DONT_FOLLOW))
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lookup_flags |= LOOKUP_FOLLOW;
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if (flags & FAN_MARK_ONLYDIR)
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lookup_flags |= LOOKUP_DIRECTORY;
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ret = user_path_at(dfd, filename, lookup_flags, path);
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if (ret)
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goto out;
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}
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/* you can only watch an inode if you have read permissions on it */
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ret = inode_permission(path->dentry->d_inode, MAY_READ);
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if (ret)
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path_put(path);
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out:
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return ret;
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}
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static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
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__u32 mask,
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unsigned int flags)
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{
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__u32 oldmask;
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spin_lock(&fsn_mark->lock);
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if (!(flags & FAN_MARK_IGNORED_MASK)) {
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oldmask = fsn_mark->mask;
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fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask));
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} else {
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oldmask = fsn_mark->ignored_mask;
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fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask));
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}
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spin_unlock(&fsn_mark->lock);
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if (!(oldmask & ~mask))
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fsnotify_destroy_mark(fsn_mark);
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return mask & oldmask;
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}
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static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
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struct vfsmount *mnt, __u32 mask,
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unsigned int flags)
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{
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struct fsnotify_mark *fsn_mark = NULL;
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__u32 removed;
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fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
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if (!fsn_mark)
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return -ENOENT;
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removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
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fsnotify_put_mark(fsn_mark);
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if (removed & mnt->mnt_fsnotify_mask)
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fsnotify_recalc_vfsmount_mask(mnt);
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return 0;
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}
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static int fanotify_remove_inode_mark(struct fsnotify_group *group,
|
|
struct inode *inode, __u32 mask,
|
|
unsigned int flags)
|
|
{
|
|
struct fsnotify_mark *fsn_mark = NULL;
|
|
__u32 removed;
|
|
|
|
fsn_mark = fsnotify_find_inode_mark(group, inode);
|
|
if (!fsn_mark)
|
|
return -ENOENT;
|
|
|
|
removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
|
|
/* matches the fsnotify_find_inode_mark() */
|
|
fsnotify_put_mark(fsn_mark);
|
|
if (removed & inode->i_fsnotify_mask)
|
|
fsnotify_recalc_inode_mask(inode);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
|
|
__u32 mask,
|
|
unsigned int flags)
|
|
{
|
|
__u32 oldmask;
|
|
|
|
spin_lock(&fsn_mark->lock);
|
|
if (!(flags & FAN_MARK_IGNORED_MASK)) {
|
|
oldmask = fsn_mark->mask;
|
|
fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask));
|
|
} else {
|
|
oldmask = fsn_mark->ignored_mask;
|
|
fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask | mask));
|
|
if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
|
|
fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
|
|
}
|
|
spin_unlock(&fsn_mark->lock);
|
|
|
|
return mask & ~oldmask;
|
|
}
|
|
|
|
static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
|
|
struct vfsmount *mnt, __u32 mask,
|
|
unsigned int flags)
|
|
{
|
|
struct fsnotify_mark *fsn_mark;
|
|
__u32 added;
|
|
|
|
fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
|
|
if (!fsn_mark) {
|
|
int ret;
|
|
|
|
if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
|
|
return -ENOSPC;
|
|
|
|
fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
|
|
if (!fsn_mark)
|
|
return -ENOMEM;
|
|
|
|
fsnotify_init_mark(fsn_mark, fanotify_free_mark);
|
|
ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0);
|
|
if (ret) {
|
|
fanotify_free_mark(fsn_mark);
|
|
return ret;
|
|
}
|
|
}
|
|
added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
|
|
fsnotify_put_mark(fsn_mark);
|
|
if (added & ~mnt->mnt_fsnotify_mask)
|
|
fsnotify_recalc_vfsmount_mask(mnt);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int fanotify_add_inode_mark(struct fsnotify_group *group,
|
|
struct inode *inode, __u32 mask,
|
|
unsigned int flags)
|
|
{
|
|
struct fsnotify_mark *fsn_mark;
|
|
__u32 added;
|
|
|
|
pr_debug("%s: group=%p inode=%p\n", __func__, group, inode);
|
|
|
|
/*
|
|
* If some other task has this inode open for write we should not add
|
|
* an ignored mark, unless that ignored mark is supposed to survive
|
|
* modification changes anyway.
|
|
*/
|
|
if ((flags & FAN_MARK_IGNORED_MASK) &&
|
|
!(flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
|
|
(atomic_read(&inode->i_writecount) > 0))
|
|
return 0;
|
|
|
|
fsn_mark = fsnotify_find_inode_mark(group, inode);
|
|
if (!fsn_mark) {
|
|
int ret;
|
|
|
|
if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
|
|
return -ENOSPC;
|
|
|
|
fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
|
|
if (!fsn_mark)
|
|
return -ENOMEM;
|
|
|
|
fsnotify_init_mark(fsn_mark, fanotify_free_mark);
|
|
ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0);
|
|
if (ret) {
|
|
fanotify_free_mark(fsn_mark);
|
|
return ret;
|
|
}
|
|
}
|
|
added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
|
|
fsnotify_put_mark(fsn_mark);
|
|
if (added & ~inode->i_fsnotify_mask)
|
|
fsnotify_recalc_inode_mask(inode);
|
|
return 0;
|
|
}
|
|
|
|
/* fanotify syscalls */
|
|
SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
|
|
{
|
|
struct fsnotify_group *group;
|
|
int f_flags, fd;
|
|
struct user_struct *user;
|
|
|
|
pr_debug("%s: flags=%d event_f_flags=%d\n",
|
|
__func__, flags, event_f_flags);
|
|
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
|
|
if (flags & ~FAN_ALL_INIT_FLAGS)
|
|
return -EINVAL;
|
|
|
|
user = get_current_user();
|
|
if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) {
|
|
free_uid(user);
|
|
return -EMFILE;
|
|
}
|
|
|
|
f_flags = O_RDWR | FMODE_NONOTIFY;
|
|
if (flags & FAN_CLOEXEC)
|
|
f_flags |= O_CLOEXEC;
|
|
if (flags & FAN_NONBLOCK)
|
|
f_flags |= O_NONBLOCK;
|
|
|
|
/* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */
|
|
group = fsnotify_alloc_group(&fanotify_fsnotify_ops);
|
|
if (IS_ERR(group))
|
|
return PTR_ERR(group);
|
|
|
|
group->fanotify_data.user = user;
|
|
atomic_inc(&user->fanotify_listeners);
|
|
|
|
group->fanotify_data.f_flags = event_f_flags;
|
|
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
|
|
mutex_init(&group->fanotify_data.access_mutex);
|
|
init_waitqueue_head(&group->fanotify_data.access_waitq);
|
|
INIT_LIST_HEAD(&group->fanotify_data.access_list);
|
|
#endif
|
|
switch (flags & FAN_ALL_CLASS_BITS) {
|
|
case FAN_CLASS_NOTIF:
|
|
group->priority = FS_PRIO_0;
|
|
break;
|
|
case FAN_CLASS_CONTENT:
|
|
group->priority = FS_PRIO_1;
|
|
break;
|
|
case FAN_CLASS_PRE_CONTENT:
|
|
group->priority = FS_PRIO_2;
|
|
break;
|
|
default:
|
|
fd = -EINVAL;
|
|
goto out_put_group;
|
|
}
|
|
|
|
if (flags & FAN_UNLIMITED_QUEUE) {
|
|
fd = -EPERM;
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
goto out_put_group;
|
|
group->max_events = UINT_MAX;
|
|
} else {
|
|
group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS;
|
|
}
|
|
|
|
if (flags & FAN_UNLIMITED_MARKS) {
|
|
fd = -EPERM;
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
goto out_put_group;
|
|
group->fanotify_data.max_marks = UINT_MAX;
|
|
} else {
|
|
group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS;
|
|
}
|
|
|
|
fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
|
|
if (fd < 0)
|
|
goto out_put_group;
|
|
|
|
return fd;
|
|
|
|
out_put_group:
|
|
fsnotify_put_group(group);
|
|
return fd;
|
|
}
|
|
|
|
SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags,
|
|
__u64 mask, int dfd,
|
|
const char __user * pathname)
|
|
{
|
|
struct inode *inode = NULL;
|
|
struct vfsmount *mnt = NULL;
|
|
struct fsnotify_group *group;
|
|
struct file *filp;
|
|
struct path path;
|
|
int ret, fput_needed;
|
|
|
|
pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
|
|
__func__, fanotify_fd, flags, dfd, pathname, mask);
|
|
|
|
/* we only use the lower 32 bits as of right now. */
|
|
if (mask & ((__u64)0xffffffff << 32))
|
|
return -EINVAL;
|
|
|
|
if (flags & ~FAN_ALL_MARK_FLAGS)
|
|
return -EINVAL;
|
|
switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
|
|
case FAN_MARK_ADD:
|
|
case FAN_MARK_REMOVE:
|
|
case FAN_MARK_FLUSH:
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
|
|
if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD))
|
|
#else
|
|
if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD))
|
|
#endif
|
|
return -EINVAL;
|
|
|
|
filp = fget_light(fanotify_fd, &fput_needed);
|
|
if (unlikely(!filp))
|
|
return -EBADF;
|
|
|
|
/* verify that this is indeed an fanotify instance */
|
|
ret = -EINVAL;
|
|
if (unlikely(filp->f_op != &fanotify_fops))
|
|
goto fput_and_out;
|
|
group = filp->private_data;
|
|
|
|
/*
|
|
* group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not
|
|
* allowed to set permissions events.
|
|
*/
|
|
ret = -EINVAL;
|
|
if (mask & FAN_ALL_PERM_EVENTS &&
|
|
group->priority == FS_PRIO_0)
|
|
goto fput_and_out;
|
|
|
|
ret = fanotify_find_path(dfd, pathname, &path, flags);
|
|
if (ret)
|
|
goto fput_and_out;
|
|
|
|
/* inode held in place by reference to path; group by fget on fd */
|
|
if (!(flags & FAN_MARK_MOUNT))
|
|
inode = path.dentry->d_inode;
|
|
else
|
|
mnt = path.mnt;
|
|
|
|
/* create/update an inode mark */
|
|
switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
|
|
case FAN_MARK_ADD:
|
|
if (flags & FAN_MARK_MOUNT)
|
|
ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags);
|
|
else
|
|
ret = fanotify_add_inode_mark(group, inode, mask, flags);
|
|
break;
|
|
case FAN_MARK_REMOVE:
|
|
if (flags & FAN_MARK_MOUNT)
|
|
ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags);
|
|
else
|
|
ret = fanotify_remove_inode_mark(group, inode, mask, flags);
|
|
break;
|
|
case FAN_MARK_FLUSH:
|
|
if (flags & FAN_MARK_MOUNT)
|
|
fsnotify_clear_vfsmount_marks_by_group(group);
|
|
else
|
|
fsnotify_clear_inode_marks_by_group(group);
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
}
|
|
|
|
path_put(&path);
|
|
fput_and_out:
|
|
fput_light(filp, fput_needed);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
|
|
asmlinkage long SyS_fanotify_mark(long fanotify_fd, long flags, __u64 mask,
|
|
long dfd, long pathname)
|
|
{
|
|
return SYSC_fanotify_mark((int) fanotify_fd, (unsigned int) flags,
|
|
mask, (int) dfd,
|
|
(const char __user *) pathname);
|
|
}
|
|
SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark);
|
|
#endif
|
|
|
|
/*
|
|
* fanotify_user_setup - Our initialization function. Note that we cannnot return
|
|
* error because we have compiled-in VFS hooks. So an (unlikely) failure here
|
|
* must result in panic().
|
|
*/
|
|
static int __init fanotify_user_setup(void)
|
|
{
|
|
fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC);
|
|
fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event,
|
|
SLAB_PANIC);
|
|
|
|
return 0;
|
|
}
|
|
device_initcall(fanotify_user_setup);
|