diff options
Diffstat (limited to 'fs/notify/fanotify')
| -rw-r--r-- | fs/notify/fanotify/Kconfig | 2 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify.c | 33 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 176 |
3 files changed, 167 insertions, 44 deletions
diff --git a/fs/notify/fanotify/Kconfig b/fs/notify/fanotify/Kconfig index 3ac36b7bf6b..7dceff005a6 100644 --- a/fs/notify/fanotify/Kconfig +++ b/fs/notify/fanotify/Kconfig @@ -6,7 +6,7 @@ config FANOTIFY ---help--- Say Y here to enable fanotify suport. fanotify is a file access notification system which differs from inotify in that it sends - and open file descriptor to the userspace listener along with + an open file descriptor to the userspace listener along with the event. If unsure, say Y. diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 85366c78cc3..f35794b97e8 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -92,7 +92,11 @@ static int fanotify_get_response_from_access(struct fsnotify_group *group, pr_debug("%s: group=%p event=%p\n", __func__, group, event); - wait_event(group->fanotify_data.access_waitq, event->response); + wait_event(group->fanotify_data.access_waitq, event->response || + atomic_read(&group->fanotify_data.bypass_perm)); + + if (!event->response) /* bypass_perm set */ + return 0; /* userspace responded, convert to something usable */ spin_lock(&event->lock); @@ -131,6 +135,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW); BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM); BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM); + BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR); pr_debug("%s: group=%p event=%p\n", __func__, group, event); @@ -160,20 +165,21 @@ static bool fanotify_should_send_event(struct fsnotify_group *group, __u32 event_mask, void *data, int data_type) { __u32 marks_mask, marks_ignored_mask; + struct path *path = data; pr_debug("%s: group=%p to_tell=%p inode_mark=%p vfsmnt_mark=%p " "mask=%x data=%p data_type=%d\n", __func__, group, to_tell, inode_mark, vfsmnt_mark, event_mask, data, data_type); - /* sorry, fanotify only gives a damn about files and dirs */ - if (!S_ISREG(to_tell->i_mode) && - !S_ISDIR(to_tell->i_mode)) - return false; - /* if we don't have enough info to send an event to userspace say no */ if (data_type != FSNOTIFY_EVENT_PATH) return false; + /* sorry, fanotify only gives a damn about files and dirs */ + if (!S_ISREG(path->dentry->d_inode->i_mode) && + !S_ISDIR(path->dentry->d_inode->i_mode)) + return false; + if (inode_mark && vfsmnt_mark) { marks_mask = (vfsmnt_mark->mask | inode_mark->mask); marks_ignored_mask = (vfsmnt_mark->ignored_mask | inode_mark->ignored_mask); @@ -194,16 +200,29 @@ static bool fanotify_should_send_event(struct fsnotify_group *group, BUG(); } + if (S_ISDIR(path->dentry->d_inode->i_mode) && + (marks_ignored_mask & FS_ISDIR)) + return false; + if (event_mask & marks_mask & ~marks_ignored_mask) return true; return false; } +static void fanotify_free_group_priv(struct fsnotify_group *group) +{ + struct user_struct *user; + + user = group->fanotify_data.user; + atomic_dec(&user->fanotify_listeners); + free_uid(user); +} + const struct fsnotify_ops fanotify_fsnotify_ops = { .handle_event = fanotify_handle_event, .should_send_event = fanotify_should_send_event, - .free_group_priv = NULL, + .free_group_priv = fanotify_free_group_priv, .free_event_priv = NULL, .freeing_mark = NULL, }; diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 5ed8e58d7bf..8b61220cffc 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -16,6 +16,10 @@ #include <asm/ioctls.h> +#define FANOTIFY_DEFAULT_MAX_EVENTS 16384 +#define FANOTIFY_DEFAULT_MAX_MARKS 8192 +#define FANOTIFY_DEFAULT_MAX_LISTENERS 128 + extern const struct fsnotify_ops fanotify_fsnotify_ops; static struct kmem_cache *fanotify_mark_cache __read_mostly; @@ -102,20 +106,29 @@ static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event) return client_fd; } -static ssize_t fill_event_metadata(struct fsnotify_group *group, +static int fill_event_metadata(struct fsnotify_group *group, struct fanotify_event_metadata *metadata, struct fsnotify_event *event) { + int ret = 0; + pr_debug("%s: group=%p metadata=%p event=%p\n", __func__, group, metadata, event); metadata->event_len = FAN_EVENT_METADATA_LEN; + metadata->metadata_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); + if (unlikely(event->mask & FAN_Q_OVERFLOW)) + metadata->fd = FAN_NOFD; + else { + metadata->fd = create_fd(group, event); + if (metadata->fd < 0) + ret = metadata->fd; + } - return metadata->fd; + return ret; } #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS @@ -196,7 +209,7 @@ static int prepare_for_access_response(struct fsnotify_group *group, mutex_lock(&group->fanotify_data.access_mutex); - if (group->fanotify_data.bypass_perm) { + if (atomic_read(&group->fanotify_data.bypass_perm)) { mutex_unlock(&group->fanotify_data.access_mutex); kmem_cache_free(fanotify_response_event_cache, re); event->response = FAN_ALLOW; @@ -253,24 +266,34 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, pr_debug("%s: group=%p event=%p\n", __func__, group, event); - fd = fill_event_metadata(group, &fanotify_event_metadata, event); - if (fd < 0) - return fd; + ret = fill_event_metadata(group, &fanotify_event_metadata, event); + if (ret < 0) + goto out; + fd = fanotify_event_metadata.fd; ret = prepare_for_access_response(group, event, fd); if (ret) goto out_close_fd; ret = -EFAULT; - if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN)) + if (copy_to_user(buf, &fanotify_event_metadata, + fanotify_event_metadata.event_len)) goto out_kill_access_response; - return FAN_EVENT_METADATA_LEN; + return fanotify_event_metadata.event_len; out_kill_access_response: remove_access_response(group, event, fd); out_close_fd: - sys_close(fd); + if (fd != FAN_NOFD) + sys_close(fd); +out: +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (event->mask & FAN_ALL_PERM_EVENTS) { + event->response = FAN_DENY; + wake_up(&group->fanotify_data.access_waitq); + } +#endif return ret; } @@ -326,7 +349,7 @@ static ssize_t fanotify_read(struct file *file, char __user *buf, ret = -EAGAIN; if (file->f_flags & O_NONBLOCK) break; - ret = -EINTR; + ret = -ERESTARTSYS; if (signal_pending(current)) break; @@ -372,14 +395,13 @@ static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t static int fanotify_release(struct inode *ignored, struct file *file) { struct fsnotify_group *group = file->private_data; - struct fanotify_response_event *re, *lre; - - pr_debug("%s: file=%p group=%p\n", __func__, file, group); #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + struct fanotify_response_event *re, *lre; + mutex_lock(&group->fanotify_data.access_mutex); - group->fanotify_data.bypass_perm = true; + atomic_inc(&group->fanotify_data.bypass_perm); list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) { pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group, @@ -433,6 +455,7 @@ static const struct file_operations fanotify_fops = { .release = fanotify_release, .unlocked_ioctl = fanotify_ioctl, .compat_ioctl = fanotify_ioctl, + .llseek = noop_llseek, }; static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) @@ -553,18 +576,24 @@ static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, __u32 mask, unsigned int flags) { - __u32 oldmask; + __u32 oldmask = -1; 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)); + __u32 tmask = fsn_mark->ignored_mask | mask; + fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); if (flags & FAN_MARK_IGNORED_SURV_MODIFY) fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; } + + if (!(flags & FAN_MARK_ONDIR)) { + __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR; + fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); + } + spin_unlock(&fsn_mark->lock); return mask & ~oldmask; @@ -576,10 +605,12 @@ static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, { struct fsnotify_mark *fsn_mark; __u32 added; + int ret = 0; 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) @@ -587,17 +618,16 @@ static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, 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; - } + if (ret) + goto err; } 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; +err: + fsnotify_put_mark(fsn_mark); + return ret; } static int fanotify_add_inode_mark(struct fsnotify_group *group, @@ -606,12 +636,24 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group, { struct fsnotify_mark *fsn_mark; __u32 added; + int ret = 0; 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) @@ -619,16 +661,16 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group, 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; - } + if (ret) + goto err; } 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; +err: + fsnotify_put_mark(fsn_mark); + return ret; } /* fanotify syscalls */ @@ -636,6 +678,7 @@ 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); @@ -646,6 +689,12 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) 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; @@ -654,15 +703,53 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ group = fsnotify_alloc_group(&fanotify_fsnotify_ops); - if (IS_ERR(group)) + if (IS_ERR(group)) { + free_uid(user); 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); + atomic_set(&group->fanotify_data.bypass_perm, 0); #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) @@ -696,13 +783,21 @@ SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags, 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_ADD: /* fallthrough */ case FAN_MARK_REMOVE: + if (!mask) + return -EINVAL; case FAN_MARK_FLUSH: 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 @@ -718,6 +813,16 @@ SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags, 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) @@ -728,7 +833,6 @@ SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags, 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)) { |