| #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/slab.h> |
| #include <linux/types.h> |
| #include <linux/uaccess.h> |
| #include <linux/compat.h> |
| #include <linux/sched/signal.h> |
| |
| #include <asm/ioctls.h> |
| |
| #include "../../mount.h" |
| #include "../fdinfo.h" |
| #include "fanotify.h" |
| |
| #define FANOTIFY_DEFAULT_MAX_EVENTS 16384 |
| #define FANOTIFY_DEFAULT_MAX_MARKS 8192 |
| #define FANOTIFY_DEFAULT_MAX_LISTENERS 128 |
| |
| /* |
| * All flags that may be specified in parameter event_f_flags of fanotify_init. |
| * |
| * Internal and external open flags are stored together in field f_flags of |
| * struct file. Only external open flags shall be allowed in event_f_flags. |
| * Internal flags like FMODE_NONOTIFY, FMODE_EXEC, FMODE_NOCMTIME shall be |
| * excluded. |
| */ |
| #define FANOTIFY_INIT_ALL_EVENT_F_BITS ( \ |
| O_ACCMODE | O_APPEND | O_NONBLOCK | \ |
| __O_SYNC | O_DSYNC | O_CLOEXEC | \ |
| O_LARGEFILE | O_NOATIME ) |
| |
| extern const struct fsnotify_ops fanotify_fsnotify_ops; |
| |
| struct kmem_cache *fanotify_mark_cache __read_mostly; |
| struct kmem_cache *fanotify_event_cachep __read_mostly; |
| struct kmem_cache *fanotify_perm_event_cachep __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_lock held. |
| */ |
| static struct fsnotify_event *get_one_event(struct fsnotify_group *group, |
| size_t count) |
| { |
| assert_spin_locked(&group->notification_lock); |
| |
| 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_lock the whole time, so this is the |
| * same event we peeked above */ |
| return fsnotify_remove_first_event(group); |
| } |
| |
| static int create_fd(struct fsnotify_group *group, |
| struct fanotify_event_info *event, |
| struct file **file) |
| { |
| int client_fd; |
| struct file *new_file; |
| |
| pr_debug("%s: group=%p event=%p\n", __func__, group, event); |
| |
| client_fd = get_unused_fd_flags(group->fanotify_data.f_flags); |
| if (client_fd < 0) |
| return client_fd; |
| |
| /* |
| * we need a new file handle for the userspace program so it can read even if it was |
| * originally opened O_WRONLY. |
| */ |
| /* 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 (event->path.dentry && event->path.mnt) |
| new_file = dentry_open(&event->path, |
| group->fanotify_data.f_flags | 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 { |
| *file = new_file; |
| } |
| |
| return client_fd; |
| } |
| |
| static int fill_event_metadata(struct fsnotify_group *group, |
| struct fanotify_event_metadata *metadata, |
| struct fsnotify_event *fsn_event, |
| struct file **file) |
| { |
| int ret = 0; |
| struct fanotify_event_info *event; |
| |
| pr_debug("%s: group=%p metadata=%p event=%p\n", __func__, |
| group, metadata, fsn_event); |
| |
| *file = NULL; |
| event = container_of(fsn_event, struct fanotify_event_info, fse); |
| metadata->event_len = FAN_EVENT_METADATA_LEN; |
| metadata->metadata_len = FAN_EVENT_METADATA_LEN; |
| metadata->vers = FANOTIFY_METADATA_VERSION; |
| metadata->reserved = 0; |
| metadata->mask = fsn_event->mask & FAN_ALL_OUTGOING_EVENTS; |
| metadata->pid = pid_vnr(event->tgid); |
| if (unlikely(fsn_event->mask & FAN_Q_OVERFLOW)) |
| metadata->fd = FAN_NOFD; |
| else { |
| metadata->fd = create_fd(group, event, file); |
| if (metadata->fd < 0) |
| ret = metadata->fd; |
| } |
| |
| return ret; |
| } |
| |
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
| static struct fanotify_perm_event_info *dequeue_event( |
| struct fsnotify_group *group, int fd) |
| { |
| struct fanotify_perm_event_info *event, *return_e = NULL; |
| |
| spin_lock(&group->notification_lock); |
| list_for_each_entry(event, &group->fanotify_data.access_list, |
| fae.fse.list) { |
| if (event->fd != fd) |
| continue; |
| |
| list_del_init(&event->fae.fse.list); |
| return_e = event; |
| break; |
| } |
| spin_unlock(&group->notification_lock); |
| |
| pr_debug("%s: found return_re=%p\n", __func__, return_e); |
| |
| return return_e; |
| } |
| |
| static int process_access_response(struct fsnotify_group *group, |
| struct fanotify_response *response_struct) |
| { |
| struct fanotify_perm_event_info *event; |
| int fd = response_struct->fd; |
| int response = response_struct->response; |
| |
| pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group, |
| fd, response); |
| /* |
| * make sure the response is valid, if invalid we do nothing and either |
| * userspace can send a valid response or we will clean it up after the |
| * timeout |
| */ |
| switch (response & ~FAN_AUDIT) { |
| case FAN_ALLOW: |
| case FAN_DENY: |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| if (fd < 0) |
| return -EINVAL; |
| |
| if ((response & FAN_AUDIT) && !group->fanotify_data.audit) |
| return -EINVAL; |
| |
| event = dequeue_event(group, fd); |
| if (!event) |
| return -ENOENT; |
| |
| event->response = response; |
| wake_up(&group->fanotify_data.access_waitq); |
| |
| return 0; |
| } |
| #endif |
| |
| 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; |
| struct file *f; |
| int fd, ret; |
| |
| pr_debug("%s: group=%p event=%p\n", __func__, group, event); |
| |
| ret = fill_event_metadata(group, &fanotify_event_metadata, event, &f); |
| if (ret < 0) |
| return ret; |
| |
| fd = fanotify_event_metadata.fd; |
| ret = -EFAULT; |
| if (copy_to_user(buf, &fanotify_event_metadata, |
| fanotify_event_metadata.event_len)) |
| goto out_close_fd; |
| |
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
| if (event->mask & FAN_ALL_PERM_EVENTS) |
| FANOTIFY_PE(event)->fd = fd; |
| #endif |
| |
| if (fd != FAN_NOFD) |
| fd_install(fd, f); |
| return fanotify_event_metadata.event_len; |
| |
| out_close_fd: |
| if (fd != FAN_NOFD) { |
| put_unused_fd(fd); |
| fput(f); |
| } |
| return ret; |
| } |
| |
| /* 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); |
| spin_lock(&group->notification_lock); |
| if (!fsnotify_notify_queue_is_empty(group)) |
| ret = POLLIN | POLLRDNORM; |
| spin_unlock(&group->notification_lock); |
| |
| 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_FUNC(wait, woken_wake_function); |
| |
| start = buf; |
| group = file->private_data; |
| |
| pr_debug("%s: group=%p\n", __func__, group); |
| |
| add_wait_queue(&group->notification_waitq, &wait); |
| while (1) { |
| spin_lock(&group->notification_lock); |
| kevent = get_one_event(group, count); |
| spin_unlock(&group->notification_lock); |
| |
| if (IS_ERR(kevent)) { |
| ret = PTR_ERR(kevent); |
| break; |
| } |
| |
| if (!kevent) { |
| ret = -EAGAIN; |
| if (file->f_flags & O_NONBLOCK) |
| break; |
| |
| ret = -ERESTARTSYS; |
| if (signal_pending(current)) |
| break; |
| |
| if (start != buf) |
| break; |
| |
| wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
| continue; |
| } |
| |
| ret = copy_event_to_user(group, kevent, buf); |
| if (unlikely(ret == -EOPENSTALE)) { |
| /* |
| * We cannot report events with stale fd so drop it. |
| * Setting ret to 0 will continue the event loop and |
| * do the right thing if there are no more events to |
| * read (i.e. return bytes read, -EAGAIN or wait). |
| */ |
| ret = 0; |
| } |
| |
| /* |
| * Permission events get queued to wait for response. Other |
| * events can be destroyed now. |
| */ |
| if (!(kevent->mask & FAN_ALL_PERM_EVENTS)) { |
| fsnotify_destroy_event(group, kevent); |
| } else { |
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
| if (ret <= 0) { |
| FANOTIFY_PE(kevent)->response = FAN_DENY; |
| wake_up(&group->fanotify_data.access_waitq); |
| } else { |
| spin_lock(&group->notification_lock); |
| list_add_tail(&kevent->list, |
| &group->fanotify_data.access_list); |
| spin_unlock(&group->notification_lock); |
| } |
| #endif |
| } |
| if (ret < 0) |
| break; |
| buf += ret; |
| count -= ret; |
| } |
| remove_wait_queue(&group->notification_waitq, &wait); |
| |
| if (start != buf && ret != -EFAULT) |
| ret = buf - start; |
| return ret; |
| } |
| |
| static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) |
| { |
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
| struct fanotify_response response = { .fd = -1, .response = -1 }; |
| struct fsnotify_group *group; |
| int ret; |
| |
| group = file->private_data; |
| |
| if (count > sizeof(response)) |
| count = sizeof(response); |
| |
| pr_debug("%s: group=%p count=%zu\n", __func__, group, count); |
| |
| if (copy_from_user(&response, buf, count)) |
| return -EFAULT; |
| |
| ret = process_access_response(group, &response); |
| if (ret < 0) |
| count = ret; |
| |
| return count; |
| #else |
| return -EINVAL; |
| #endif |
| } |
| |
| static int fanotify_release(struct inode *ignored, struct file *file) |
| { |
| struct fsnotify_group *group = file->private_data; |
| |
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
| struct fanotify_perm_event_info *event, *next; |
| struct fsnotify_event *fsn_event; |
| |
| /* |
| * Stop new events from arriving in the notification queue. since |
| * userspace cannot use fanotify fd anymore, no event can enter or |
| * leave access_list by now either. |
| */ |
| fsnotify_group_stop_queueing(group); |
| |
| /* |
| * Process all permission events on access_list and notification queue |
| * and simulate reply from userspace. |
| */ |
| spin_lock(&group->notification_lock); |
| list_for_each_entry_safe(event, next, &group->fanotify_data.access_list, |
| fae.fse.list) { |
| pr_debug("%s: found group=%p event=%p\n", __func__, group, |
| event); |
| |
| list_del_init(&event->fae.fse.list); |
| event->response = FAN_ALLOW; |
| } |
| |
| /* |
| * Destroy all non-permission events. For permission events just |
| * dequeue them and set the response. They will be freed once the |
| * response is consumed and fanotify_get_response() returns. |
| */ |
| while (!fsnotify_notify_queue_is_empty(group)) { |
| fsn_event = fsnotify_remove_first_event(group); |
| if (!(fsn_event->mask & FAN_ALL_PERM_EVENTS)) { |
| spin_unlock(&group->notification_lock); |
| fsnotify_destroy_event(group, fsn_event); |
| spin_lock(&group->notification_lock); |
| } else |
| FANOTIFY_PE(fsn_event)->response = FAN_ALLOW; |
| } |
| spin_unlock(&group->notification_lock); |
| |
| /* Response for all permission events it set, wakeup waiters */ |
| wake_up(&group->fanotify_data.access_waitq); |
| #endif |
| |
| /* matches the fanotify_init->fsnotify_alloc_group */ |
| fsnotify_destroy_group(group); |
| |
| return 0; |
| } |
| |
| static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct fsnotify_group *group; |
| struct fsnotify_event *fsn_event; |
| void __user *p; |
| int ret = -ENOTTY; |
| size_t send_len = 0; |
| |
| group = file->private_data; |
| |
| p = (void __user *) arg; |
| |
| switch (cmd) { |
| case FIONREAD: |
| spin_lock(&group->notification_lock); |
| list_for_each_entry(fsn_event, &group->notification_list, list) |
| send_len += FAN_EVENT_METADATA_LEN; |
| spin_unlock(&group->notification_lock); |
| ret = put_user(send_len, (int __user *) p); |
| break; |
| } |
| |
| return ret; |
| } |
| |
| static const struct file_operations fanotify_fops = { |
| .show_fdinfo = fanotify_show_fdinfo, |
| .poll = fanotify_poll, |
| .read = fanotify_read, |
| .write = fanotify_write, |
| .fasync = NULL, |
| .release = fanotify_release, |
| .unlocked_ioctl = fanotify_ioctl, |
| .compat_ioctl = fanotify_ioctl, |
| .llseek = noop_llseek, |
| }; |
| |
| 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 fd f = fdget(dfd); |
| |
| ret = -EBADF; |
| if (!f.file) |
| goto out; |
| |
| ret = -ENOTDIR; |
| if ((flags & FAN_MARK_ONLYDIR) && |
| !(S_ISDIR(file_inode(f.file)->i_mode))) { |
| fdput(f); |
| goto out; |
| } |
| |
| *path = f.file->f_path; |
| path_get(path); |
| fdput(f); |
| } 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, |
| int *destroy) |
| { |
| __u32 oldmask = 0; |
| |
| spin_lock(&fsn_mark->lock); |
| if (!(flags & FAN_MARK_IGNORED_MASK)) { |
| __u32 tmask = fsn_mark->mask & ~mask; |
| |
| if (flags & FAN_MARK_ONDIR) |
| tmask &= ~FAN_ONDIR; |
| |
| oldmask = fsn_mark->mask; |
| fsn_mark->mask = tmask; |
| } else { |
| __u32 tmask = fsn_mark->ignored_mask & ~mask; |
| if (flags & FAN_MARK_ONDIR) |
| tmask &= ~FAN_ONDIR; |
| fsn_mark->ignored_mask = tmask; |
| } |
| *destroy = !(fsn_mark->mask | fsn_mark->ignored_mask); |
| spin_unlock(&fsn_mark->lock); |
| |
| 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; |
| int destroy_mark; |
| |
| mutex_lock(&group->mark_mutex); |
| fsn_mark = fsnotify_find_mark(&real_mount(mnt)->mnt_fsnotify_marks, |
| group); |
| if (!fsn_mark) { |
| mutex_unlock(&group->mark_mutex); |
| return -ENOENT; |
| } |
| |
| removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, |
| &destroy_mark); |
| if (removed & real_mount(mnt)->mnt_fsnotify_mask) |
| fsnotify_recalc_mask(real_mount(mnt)->mnt_fsnotify_marks); |
| if (destroy_mark) |
| fsnotify_detach_mark(fsn_mark); |
| mutex_unlock(&group->mark_mutex); |
| if (destroy_mark) |
| fsnotify_free_mark(fsn_mark); |
| |
| fsnotify_put_mark(fsn_mark); |
| 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; |
| int destroy_mark; |
| |
| mutex_lock(&group->mark_mutex); |
| fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group); |
| if (!fsn_mark) { |
| mutex_unlock(&group->mark_mutex); |
| return -ENOENT; |
| } |
| |
| removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, |
| &destroy_mark); |
| if (removed & inode->i_fsnotify_mask) |
| fsnotify_recalc_mask(inode->i_fsnotify_marks); |
| if (destroy_mark) |
| fsnotify_detach_mark(fsn_mark); |
| mutex_unlock(&group->mark_mutex); |
| if (destroy_mark) |
| fsnotify_free_mark(fsn_mark); |
| |
| /* matches the fsnotify_find_mark() */ |
| fsnotify_put_mark(fsn_mark); |
| |
| return 0; |
| } |
| |
| static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, |
| __u32 mask, |
| unsigned int flags) |
| { |
| __u32 oldmask = -1; |
| |
| spin_lock(&fsn_mark->lock); |
| if (!(flags & FAN_MARK_IGNORED_MASK)) { |
| __u32 tmask = fsn_mark->mask | mask; |
| |
| if (flags & FAN_MARK_ONDIR) |
| tmask |= FAN_ONDIR; |
| |
| oldmask = fsn_mark->mask; |
| fsn_mark->mask = tmask; |
| } else { |
| __u32 tmask = fsn_mark->ignored_mask | mask; |
| if (flags & FAN_MARK_ONDIR) |
| tmask |= FAN_ONDIR; |
| |
| fsn_mark->ignored_mask = tmask; |
| 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 struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, |
| struct inode *inode, |
| struct vfsmount *mnt) |
| { |
| struct fsnotify_mark *mark; |
| int ret; |
| |
| if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) |
| return ERR_PTR(-ENOSPC); |
| |
| mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); |
| if (!mark) |
| return ERR_PTR(-ENOMEM); |
| |
| fsnotify_init_mark(mark, group); |
| ret = fsnotify_add_mark_locked(mark, inode, mnt, 0); |
| if (ret) { |
| fsnotify_put_mark(mark); |
| return ERR_PTR(ret); |
| } |
| |
| return mark; |
| } |
| |
| |
| 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; |
| |
| mutex_lock(&group->mark_mutex); |
| fsn_mark = fsnotify_find_mark(&real_mount(mnt)->mnt_fsnotify_marks, |
| group); |
| if (!fsn_mark) { |
| fsn_mark = fanotify_add_new_mark(group, NULL, mnt); |
| if (IS_ERR(fsn_mark)) { |
| mutex_unlock(&group->mark_mutex); |
| return PTR_ERR(fsn_mark); |
| } |
| } |
| added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
| if (added & ~real_mount(mnt)->mnt_fsnotify_mask) |
| fsnotify_recalc_mask(real_mount(mnt)->mnt_fsnotify_marks); |
| mutex_unlock(&group->mark_mutex); |
| |
| fsnotify_put_mark(fsn_mark); |
| 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; |
| |
| mutex_lock(&group->mark_mutex); |
| fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group); |
| if (!fsn_mark) { |
| fsn_mark = fanotify_add_new_mark(group, inode, NULL); |
| if (IS_ERR(fsn_mark)) { |
| mutex_unlock(&group->mark_mutex); |
| return PTR_ERR(fsn_mark); |
| } |
| } |
| added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
| if (added & ~inode->i_fsnotify_mask) |
| fsnotify_recalc_mask(inode->i_fsnotify_marks); |
| mutex_unlock(&group->mark_mutex); |
| |
| fsnotify_put_mark(fsn_mark); |
| 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; |
| struct fanotify_event_info *oevent; |
| |
| pr_debug("%s: flags=%d event_f_flags=%d\n", |
| __func__, flags, event_f_flags); |
| |
| if (!capable(CAP_SYS_ADMIN)) |
| return -EPERM; |
| |
| #ifdef CONFIG_AUDITSYSCALL |
| if (flags & ~(FAN_ALL_INIT_FLAGS | FAN_ENABLE_AUDIT)) |
| #else |
| if (flags & ~FAN_ALL_INIT_FLAGS) |
| #endif |
| return -EINVAL; |
| |
| if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS) |
| return -EINVAL; |
| |
| switch (event_f_flags & O_ACCMODE) { |
| case O_RDONLY: |
| case O_RDWR: |
| case O_WRONLY: |
| break; |
| default: |
| 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)) { |
| free_uid(user); |
| return PTR_ERR(group); |
| } |
| |
| group->fanotify_data.user = user; |
| atomic_inc(&user->fanotify_listeners); |
| |
| oevent = fanotify_alloc_event(NULL, FS_Q_OVERFLOW, NULL); |
| if (unlikely(!oevent)) { |
| fd = -ENOMEM; |
| goto out_destroy_group; |
| } |
| group->overflow_event = &oevent->fse; |
| |
| if (force_o_largefile()) |
| event_f_flags |= O_LARGEFILE; |
| group->fanotify_data.f_flags = event_f_flags; |
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
| 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_destroy_group; |
| } |
| |
| if (flags & FAN_UNLIMITED_QUEUE) { |
| fd = -EPERM; |
| if (!capable(CAP_SYS_ADMIN)) |
| goto out_destroy_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_destroy_group; |
| group->fanotify_data.max_marks = UINT_MAX; |
| } else { |
| group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS; |
| } |
| |
| if (flags & FAN_ENABLE_AUDIT) { |
| fd = -EPERM; |
| if (!capable(CAP_AUDIT_WRITE)) |
| goto out_destroy_group; |
| group->fanotify_data.audit = true; |
| } |
| |
| fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); |
| if (fd < 0) |
| goto out_destroy_group; |
| |
| return fd; |
| |
| out_destroy_group: |
| fsnotify_destroy_group(group); |
| return fd; |
| } |
| |
| SYSCALL_DEFINE5(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 fd f; |
| struct path path; |
| int ret; |
| |
| 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: /* fallthrough */ |
| case FAN_MARK_REMOVE: |
| if (!mask) |
| return -EINVAL; |
| break; |
| case FAN_MARK_FLUSH: |
| if (flags & ~(FAN_MARK_MOUNT | FAN_MARK_FLUSH)) |
| return -EINVAL; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| if (mask & FAN_ONDIR) { |
| flags |= FAN_MARK_ONDIR; |
| mask &= ~FAN_ONDIR; |
| } |
| |
| #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; |
| |
| f = fdget(fanotify_fd); |
| if (unlikely(!f.file)) |
| return -EBADF; |
| |
| /* verify that this is indeed an fanotify instance */ |
| ret = -EINVAL; |
| if (unlikely(f.file->f_op != &fanotify_fops)) |
| goto fput_and_out; |
| group = f.file->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; |
| |
| if (flags & FAN_MARK_FLUSH) { |
| ret = 0; |
| if (flags & FAN_MARK_MOUNT) |
| fsnotify_clear_vfsmount_marks_by_group(group); |
| else |
| fsnotify_clear_inode_marks_by_group(group); |
| 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)) { |
| 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; |
| default: |
| ret = -EINVAL; |
| } |
| |
| path_put(&path); |
| fput_and_out: |
| fdput(f); |
| return ret; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| COMPAT_SYSCALL_DEFINE6(fanotify_mark, |
| int, fanotify_fd, unsigned int, flags, |
| __u32, mask0, __u32, mask1, int, dfd, |
| const char __user *, pathname) |
| { |
| return sys_fanotify_mark(fanotify_fd, flags, |
| #ifdef __BIG_ENDIAN |
| ((__u64)mask0 << 32) | mask1, |
| #else |
| ((__u64)mask1 << 32) | mask0, |
| #endif |
| dfd, pathname); |
| } |
| #endif |
| |
| /* |
| * fanotify_user_setup - Our initialization function. Note that we cannot 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_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC); |
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
| fanotify_perm_event_cachep = KMEM_CACHE(fanotify_perm_event_info, |
| SLAB_PANIC); |
| #endif |
| |
| return 0; |
| } |
| device_initcall(fanotify_user_setup); |