--- zzzz-none-000/linux-3.10.107/fs/notify/fanotify/fanotify.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/fs/notify/fanotify/fanotify.c 2021-02-04 17:41:59.000000000 +0000 @@ -9,104 +9,67 @@ #include #include -static bool should_merge(struct fsnotify_event *old, struct fsnotify_event *new) +#include "fanotify.h" + +static bool should_merge(struct fsnotify_event *old_fsn, + struct fsnotify_event *new_fsn) { - pr_debug("%s: old=%p new=%p\n", __func__, old, new); + struct fanotify_event_info *old, *new; - if (old->to_tell == new->to_tell && - old->data_type == new->data_type && - old->tgid == new->tgid) { - switch (old->data_type) { - case (FSNOTIFY_EVENT_PATH): -#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS - /* dont merge two permission events */ - if ((old->mask & FAN_ALL_PERM_EVENTS) && - (new->mask & FAN_ALL_PERM_EVENTS)) - return false; -#endif - if ((old->path.mnt == new->path.mnt) && - (old->path.dentry == new->path.dentry)) - return true; - break; - case (FSNOTIFY_EVENT_NONE): - return true; - default: - BUG(); - }; - } + pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn); + old = FANOTIFY_E(old_fsn); + new = FANOTIFY_E(new_fsn); + + if (old_fsn->inode == new_fsn->inode && old->tgid == new->tgid && + old->path.mnt == new->path.mnt && + old->path.dentry == new->path.dentry) + return true; return false; } /* and the list better be locked by something too! */ -static struct fsnotify_event *fanotify_merge(struct list_head *list, - struct fsnotify_event *event) +static int fanotify_merge(struct list_head *list, struct fsnotify_event *event) { - struct fsnotify_event_holder *test_holder; - struct fsnotify_event *test_event = NULL; - struct fsnotify_event *new_event; + struct fsnotify_event *test_event; + bool do_merge = false; pr_debug("%s: list=%p event=%p\n", __func__, list, event); +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + /* + * Don't merge a permission event with any other event so that we know + * the event structure we have created in fanotify_handle_event() is the + * one we should check for permission response. + */ + if (event->mask & FAN_ALL_PERM_EVENTS) + return 0; +#endif - list_for_each_entry_reverse(test_holder, list, event_list) { - if (should_merge(test_holder->event, event)) { - test_event = test_holder->event; + list_for_each_entry_reverse(test_event, list, list) { + if (should_merge(test_event, event)) { + do_merge = true; break; } } - if (!test_event) - return NULL; - - fsnotify_get_event(test_event); - - /* if they are exactly the same we are done */ - if (test_event->mask == event->mask) - return test_event; - - /* - * if the refcnt == 2 this is the only queue - * for this event and so we can update the mask - * in place. - */ - if (atomic_read(&test_event->refcnt) == 2) { - test_event->mask |= event->mask; - return test_event; - } - - new_event = fsnotify_clone_event(test_event); - - /* done with test_event */ - fsnotify_put_event(test_event); - - /* couldn't allocate memory, merge was not possible */ - if (unlikely(!new_event)) - return ERR_PTR(-ENOMEM); - - /* build new event and replace it on the list */ - new_event->mask = (test_event->mask | event->mask); - fsnotify_replace_event(test_holder, new_event); + if (!do_merge) + return 0; - /* we hold a reference on new_event from clone_event */ - return new_event; + test_event->mask |= event->mask; + return 1; } #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS -static int fanotify_get_response_from_access(struct fsnotify_group *group, - struct fsnotify_event *event) +static int fanotify_get_response(struct fsnotify_group *group, + struct fanotify_perm_event_info *event) { int ret; pr_debug("%s: group=%p event=%p\n", __func__, group, event); - wait_event(group->fanotify_data.access_waitq, event->response || - atomic_read(&group->fanotify_data.bypass_perm)); - - if (!event->response) /* bypass_perm set */ - return 0; + wait_event(group->fanotify_data.access_waitq, event->response); /* userspace responded, convert to something usable */ - spin_lock(&event->lock); switch (event->response) { case FAN_ALLOW: ret = 0; @@ -116,7 +79,6 @@ ret = -EPERM; } event->response = 0; - spin_unlock(&event->lock); pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__, group, event, ret); @@ -125,66 +87,25 @@ } #endif -static int fanotify_handle_event(struct fsnotify_group *group, - struct fsnotify_mark *inode_mark, - struct fsnotify_mark *fanotify_mark, - struct fsnotify_event *event) -{ - int ret = 0; - struct fsnotify_event *notify_event = NULL; - - BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS); - BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY); - BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); - BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE); - BUILD_BUG_ON(FAN_OPEN != FS_OPEN); - BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD); - 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); - - notify_event = fsnotify_add_notify_event(group, event, NULL, fanotify_merge); - if (IS_ERR(notify_event)) - return PTR_ERR(notify_event); - -#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS - if (event->mask & FAN_ALL_PERM_EVENTS) { - /* if we merged we need to wait on the new event */ - if (notify_event) - event = notify_event; - ret = fanotify_get_response_from_access(group, event); - } -#endif - - if (notify_event) - fsnotify_put_event(notify_event); - - return ret; -} - -static bool fanotify_should_send_event(struct fsnotify_group *group, - struct inode *to_tell, - struct fsnotify_mark *inode_mark, +static bool fanotify_should_send_event(struct fsnotify_mark *inode_mark, struct fsnotify_mark *vfsmnt_mark, - __u32 event_mask, void *data, int data_type) + 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); + pr_debug("%s: inode_mark=%p vfsmnt_mark=%p mask=%x data=%p" + " data_type=%d\n", __func__, inode_mark, vfsmnt_mark, + event_mask, data, data_type); /* 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)) + if (!d_is_reg(path->dentry) && + !d_can_lookup(path->dentry)) return false; if (inode_mark && vfsmnt_mark) { @@ -207,16 +128,104 @@ BUG(); } - if (S_ISDIR(path->dentry->d_inode->i_mode) && - (marks_ignored_mask & FS_ISDIR)) + if (d_is_dir(path->dentry) && + !(marks_mask & FS_ISDIR & ~marks_ignored_mask)) return false; - if (event_mask & marks_mask & ~marks_ignored_mask) + if (event_mask & FAN_ALL_OUTGOING_EVENTS & marks_mask & + ~marks_ignored_mask) return true; return false; } +struct fanotify_event_info *fanotify_alloc_event(struct inode *inode, u32 mask, + struct path *path) +{ + struct fanotify_event_info *event; + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (mask & FAN_ALL_PERM_EVENTS) { + struct fanotify_perm_event_info *pevent; + + pevent = kmem_cache_alloc(fanotify_perm_event_cachep, + GFP_KERNEL); + if (!pevent) + return NULL; + event = &pevent->fae; + pevent->response = 0; + goto init; + } +#endif + event = kmem_cache_alloc(fanotify_event_cachep, GFP_KERNEL); + if (!event) + return NULL; +init: __maybe_unused + fsnotify_init_event(&event->fse, inode, mask); + event->tgid = get_pid(task_tgid(current)); + if (path) { + event->path = *path; + path_get(&event->path); + } else { + event->path.mnt = NULL; + event->path.dentry = NULL; + } + return event; +} + +static int fanotify_handle_event(struct fsnotify_group *group, + struct inode *inode, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *fanotify_mark, + u32 mask, void *data, int data_type, + const unsigned char *file_name, u32 cookie) +{ + int ret = 0; + struct fanotify_event_info *event; + struct fsnotify_event *fsn_event; + + BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS); + BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY); + BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); + BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE); + BUILD_BUG_ON(FAN_OPEN != FS_OPEN); + BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD); + 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); + + if (!fanotify_should_send_event(inode_mark, fanotify_mark, mask, data, + data_type)) + return 0; + + pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, + mask); + + event = fanotify_alloc_event(inode, mask, data); + if (unlikely(!event)) + return -ENOMEM; + + fsn_event = &event->fse; + ret = fsnotify_add_event(group, fsn_event, fanotify_merge); + if (ret) { + /* Permission events shouldn't be merged */ + BUG_ON(ret == 1 && mask & FAN_ALL_PERM_EVENTS); + /* Our event wasn't used in the end. Free it. */ + fsnotify_destroy_event(group, fsn_event); + + return 0; + } + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (mask & FAN_ALL_PERM_EVENTS) { + ret = fanotify_get_response(group, FANOTIFY_PE(fsn_event)); + fsnotify_destroy_event(group, fsn_event); + } +#endif + return ret; +} + static void fanotify_free_group_priv(struct fsnotify_group *group) { struct user_struct *user; @@ -226,10 +235,25 @@ free_uid(user); } +static void fanotify_free_event(struct fsnotify_event *fsn_event) +{ + struct fanotify_event_info *event; + + event = FANOTIFY_E(fsn_event); + path_put(&event->path); + put_pid(event->tgid); +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (fsn_event->mask & FAN_ALL_PERM_EVENTS) { + kmem_cache_free(fanotify_perm_event_cachep, + FANOTIFY_PE(fsn_event)); + return; + } +#endif + kmem_cache_free(fanotify_event_cachep, event); +} + const struct fsnotify_ops fanotify_fsnotify_ops = { .handle_event = fanotify_handle_event, - .should_send_event = fanotify_should_send_event, .free_group_priv = fanotify_free_group_priv, - .free_event_priv = NULL, - .freeing_mark = NULL, + .free_event = fanotify_free_event, };