+#include <linux/fanotify.h>
#include <linux/fcntl.h>
+#include <linux/file.h>
#include <linux/fs.h>
#include <linux/anon_inodes.h>
#include <linux/fsnotify_backend.h>
+#include <linux/init.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/poll.h>
#include <linux/security.h>
#include <linux/syscalls.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
-#include "fanotify.h"
+#include <asm/ioctls.h>
+
+extern const struct fsnotify_ops fanotify_fsnotify_ops;
+
+static struct kmem_cache *fanotify_mark_cache __read_mostly;
+
+/*
+ * Get an fsnotify notification event if one exists and is small
+ * enough to fit in "count". Return an error pointer if the count
+ * is not large enough.
+ *
+ * Called with the group->notification_mutex held.
+ */
+static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
+ size_t count)
+{
+ BUG_ON(!mutex_is_locked(&group->notification_mutex));
+
+ pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
+
+ if (fsnotify_notify_queue_is_empty(group))
+ return NULL;
+
+ if (FAN_EVENT_METADATA_LEN > count)
+ return ERR_PTR(-EINVAL);
+
+ /* held the notification_mutex the whole time, so this is the
+ * same event we peeked above */
+ return fsnotify_remove_notify_event(group);
+}
+
+static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
+{
+ int client_fd;
+ struct dentry *dentry;
+ struct vfsmount *mnt;
+ struct file *new_file;
+
+ pr_debug("%s: group=%p event=%p\n", __func__, group, event);
+
+ client_fd = get_unused_fd();
+ if (client_fd < 0)
+ return client_fd;
+
+ if (event->data_type != FSNOTIFY_EVENT_PATH) {
+ WARN_ON(1);
+ put_unused_fd(client_fd);
+ return -EINVAL;
+ }
+
+ /*
+ * we need a new file handle for the userspace program so it can read even if it was
+ * originally opened O_WRONLY.
+ */
+ dentry = dget(event->path.dentry);
+ mnt = mntget(event->path.mnt);
+ /* it's possible this event was an overflow event. in that case dentry and mnt
+ * are NULL; That's fine, just don't call dentry open */
+ if (dentry && mnt)
+ new_file = dentry_open(dentry, mnt,
+ O_RDONLY | O_LARGEFILE | FMODE_NONOTIFY,
+ current_cred());
+ else
+ new_file = ERR_PTR(-EOVERFLOW);
+ if (IS_ERR(new_file)) {
+ /*
+ * we still send an event even if we can't open the file. this
+ * can happen when say tasks are gone and we try to open their
+ * /proc files or we try to open a WRONLY file like in sysfs
+ * we just send the errno to userspace since there isn't much
+ * else we can do.
+ */
+ put_unused_fd(client_fd);
+ client_fd = PTR_ERR(new_file);
+ } else {
+ fd_install(client_fd, new_file);
+ }
+
+ return client_fd;
+}
+
+static ssize_t fill_event_metadata(struct fsnotify_group *group,
+ struct fanotify_event_metadata *metadata,
+ struct fsnotify_event *event)
+{
+ pr_debug("%s: group=%p metadata=%p event=%p\n", __func__,
+ group, metadata, event);
+
+ metadata->event_len = FAN_EVENT_METADATA_LEN;
+ metadata->vers = FANOTIFY_METADATA_VERSION;
+ metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS;
+ metadata->pid = pid_vnr(event->tgid);
+ metadata->fd = create_fd(group, event);
+
+ return metadata->fd;
+}
+
+static ssize_t copy_event_to_user(struct fsnotify_group *group,
+ struct fsnotify_event *event,
+ char __user *buf)
+{
+ struct fanotify_event_metadata fanotify_event_metadata;
+ int ret;
+
+ pr_debug("%s: group=%p event=%p\n", __func__, group, event);
+
+ ret = fill_event_metadata(group, &fanotify_event_metadata, event);
+ if (ret < 0)
+ return ret;
+
+ if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN))
+ return -EFAULT;
+
+ return FAN_EVENT_METADATA_LEN;
+}
+
+/* intofiy userspace file descriptor functions */
+static unsigned int fanotify_poll(struct file *file, poll_table *wait)
+{
+ struct fsnotify_group *group = file->private_data;
+ int ret = 0;
+
+ poll_wait(file, &group->notification_waitq, wait);
+ mutex_lock(&group->notification_mutex);
+ if (!fsnotify_notify_queue_is_empty(group))
+ ret = POLLIN | POLLRDNORM;
+ mutex_unlock(&group->notification_mutex);
+
+ return ret;
+}
+
+static ssize_t fanotify_read(struct file *file, char __user *buf,
+ size_t count, loff_t *pos)
+{
+ struct fsnotify_group *group;
+ struct fsnotify_event *kevent;
+ char __user *start;
+ int ret;
+ DEFINE_WAIT(wait);
+
+ start = buf;
+ group = file->private_data;
+
+ pr_debug("%s: group=%p\n", __func__, group);
+
+ while (1) {
+ prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE);
+
+ mutex_lock(&group->notification_mutex);
+ kevent = get_one_event(group, count);
+ mutex_unlock(&group->notification_mutex);
+
+ if (kevent) {
+ ret = PTR_ERR(kevent);
+ if (IS_ERR(kevent))
+ break;
+ ret = copy_event_to_user(group, kevent, buf);
+ fsnotify_put_event(kevent);
+ if (ret < 0)
+ break;
+ buf += ret;
+ count -= ret;
+ continue;
+ }
+
+ ret = -EAGAIN;
+ if (file->f_flags & O_NONBLOCK)
+ break;
+ ret = -EINTR;
+ if (signal_pending(current))
+ break;
+
+ if (start != buf)
+ break;
+
+ schedule();
+ }
+
+ finish_wait(&group->notification_waitq, &wait);
+ if (start != buf && ret != -EFAULT)
+ ret = buf - start;
+ return ret;
+}
static int fanotify_release(struct inode *ignored, struct file *file)
{
return 0;
}
+static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct fsnotify_group *group;
+ struct fsnotify_event_holder *holder;
+ void __user *p;
+ int ret = -ENOTTY;
+ size_t send_len = 0;
+
+ group = file->private_data;
+
+ p = (void __user *) arg;
+
+ switch (cmd) {
+ case FIONREAD:
+ mutex_lock(&group->notification_mutex);
+ list_for_each_entry(holder, &group->notification_list, event_list)
+ send_len += FAN_EVENT_METADATA_LEN;
+ mutex_unlock(&group->notification_mutex);
+ ret = put_user(send_len, (int __user *) p);
+ break;
+ }
+
+ return ret;
+}
+
static const struct file_operations fanotify_fops = {
- .poll = NULL,
- .read = NULL,
+ .poll = fanotify_poll,
+ .read = fanotify_read,
.fasync = NULL,
.release = fanotify_release,
- .unlocked_ioctl = NULL,
- .compat_ioctl = NULL,
+ .unlocked_ioctl = fanotify_ioctl,
+ .compat_ioctl = fanotify_ioctl,
};
+static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)
+{
+ kmem_cache_free(fanotify_mark_cache, fsn_mark);
+}
+
+static int fanotify_find_path(int dfd, const char __user *filename,
+ struct path *path, unsigned int flags)
+{
+ int ret;
+
+ pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__,
+ dfd, filename, flags);
+
+ if (filename == NULL) {
+ struct file *file;
+ int fput_needed;
+
+ ret = -EBADF;
+ file = fget_light(dfd, &fput_needed);
+ if (!file)
+ goto out;
+
+ ret = -ENOTDIR;
+ if ((flags & FAN_MARK_ONLYDIR) &&
+ !(S_ISDIR(file->f_path.dentry->d_inode->i_mode))) {
+ fput_light(file, fput_needed);
+ goto out;
+ }
+
+ *path = file->f_path;
+ path_get(path);
+ fput_light(file, fput_needed);
+ } else {
+ unsigned int lookup_flags = 0;
+
+ if (!(flags & FAN_MARK_DONT_FOLLOW))
+ lookup_flags |= LOOKUP_FOLLOW;
+ if (flags & FAN_MARK_ONLYDIR)
+ lookup_flags |= LOOKUP_DIRECTORY;
+
+ ret = user_path_at(dfd, filename, lookup_flags, path);
+ if (ret)
+ goto out;
+ }
+
+ /* you can only watch an inode if you have read permissions on it */
+ ret = inode_permission(path->dentry->d_inode, MAY_READ);
+ if (ret)
+ path_put(path);
+out:
+ return ret;
+}
+
+static __u32 fanotify_mark_remove_from_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));
+ }
+ spin_unlock(&fsn_mark->lock);
+
+ if (!(oldmask & ~mask))
+ fsnotify_destroy_mark(fsn_mark);
+
+ return mask & oldmask;
+}
+
+static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
+ struct vfsmount *mnt, __u32 mask,
+ unsigned int flags)
+{
+ struct fsnotify_mark *fsn_mark = NULL;
+ __u32 removed;
+
+ fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
+ if (!fsn_mark)
+ return -ENOENT;
+
+ removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
+ fsnotify_put_mark(fsn_mark);
+ if (removed & group->mask)
+ fsnotify_recalc_group_mask(group);
+ if (removed & mnt->mnt_fsnotify_mask)
+ fsnotify_recalc_vfsmount_mask(mnt);
+
+ return 0;
+}
+
+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 & group->mask)
+ fsnotify_recalc_group_mask(group);
+ 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;
+
+ 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) {
+ if (added & ~group->mask)
+ fsnotify_recalc_group_mask(group);
+ 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);
+
+ fsn_mark = fsnotify_find_inode_mark(group, inode);
+ if (!fsn_mark) {
+ int ret;
+
+ 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) {
+ if (added & ~group->mask)
+ fsnotify_recalc_group_mask(group);
+ if (added & ~inode->i_fsnotify_mask)
+ fsnotify_recalc_inode_mask(inode);
+ }
+ return 0;
+}
+
/* fanotify syscalls */
SYSCALL_DEFINE3(fanotify_init, unsigned int, flags, unsigned int, event_f_flags,
unsigned int, priority)
return fd;
}
-SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags,
- __u64, mask, int, dfd, const char __user *, pathname)
+SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags,
+ __u64 mask, int dfd,
+ const char __user * pathname)
{
- return -ENOSYS;
+ 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;
+ }
+ if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD))
+ 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;
+
+ 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;
+ group = filp->private_data;
+
+ /* 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);
+ fsnotify_recalc_group_mask(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);
+
+ return 0;
}
+device_initcall(fanotify_user_setup);
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