From 392e8802486cb573b916e746010e141a75f507e6 Mon Sep 17 00:00:00 2001 From: Kevin Date: Sat, 15 Nov 2014 09:58:27 +0800 Subject: init android origin source code --- ANDROID_3.4.5/fs/notify/fanotify/Kconfig | 26 + ANDROID_3.4.5/fs/notify/fanotify/Makefile | 1 + ANDROID_3.4.5/fs/notify/fanotify/fanotify.c | 228 ++++++ ANDROID_3.4.5/fs/notify/fanotify/fanotify_user.c | 893 +++++++++++++++++++++++ 4 files changed, 1148 insertions(+) create mode 100644 ANDROID_3.4.5/fs/notify/fanotify/Kconfig create mode 100644 ANDROID_3.4.5/fs/notify/fanotify/Makefile create mode 100644 ANDROID_3.4.5/fs/notify/fanotify/fanotify.c create mode 100644 ANDROID_3.4.5/fs/notify/fanotify/fanotify_user.c (limited to 'ANDROID_3.4.5/fs/notify/fanotify') diff --git a/ANDROID_3.4.5/fs/notify/fanotify/Kconfig b/ANDROID_3.4.5/fs/notify/fanotify/Kconfig new file mode 100644 index 00000000..7dceff00 --- /dev/null +++ b/ANDROID_3.4.5/fs/notify/fanotify/Kconfig @@ -0,0 +1,26 @@ +config FANOTIFY + bool "Filesystem wide access notification" + select FSNOTIFY + select ANON_INODES + default n + ---help--- + Say Y here to enable fanotify suport. fanotify is a file access + notification system which differs from inotify in that it sends + an open file descriptor to the userspace listener along with + the event. + + If unsure, say Y. + +config FANOTIFY_ACCESS_PERMISSIONS + bool "fanotify permissions checking" + depends on FANOTIFY + depends on SECURITY + default n + ---help--- + Say Y here is you want fanotify listeners to be able to make permissions + decisions concerning filesystem events. This is used by some fanotify + listeners which need to scan files before allowing the system access to + use those files. This is used by some anti-malware vendors and by some + hierarchical storage managent systems. + + If unsure, say N. diff --git a/ANDROID_3.4.5/fs/notify/fanotify/Makefile b/ANDROID_3.4.5/fs/notify/fanotify/Makefile new file mode 100644 index 00000000..0999213e --- /dev/null +++ b/ANDROID_3.4.5/fs/notify/fanotify/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_FANOTIFY) += fanotify.o fanotify_user.o diff --git a/ANDROID_3.4.5/fs/notify/fanotify/fanotify.c b/ANDROID_3.4.5/fs/notify/fanotify/fanotify.c new file mode 100644 index 00000000..f35794b9 --- /dev/null +++ b/ANDROID_3.4.5/fs/notify/fanotify/fanotify.c @@ -0,0 +1,228 @@ +#include +#include +#include +#include +#include +#include /* UINT_MAX */ +#include +#include +#include +#include + +static bool should_merge(struct fsnotify_event *old, struct fsnotify_event *new) +{ + pr_debug("%s: old=%p new=%p\n", __func__, 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): + if ((old->path.mnt == new->path.mnt) && + (old->path.dentry == new->path.dentry)) + return true; + case (FSNOTIFY_EVENT_NONE): + return true; + default: + BUG(); + }; + } + 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) +{ + struct fsnotify_event_holder *test_holder; + struct fsnotify_event *test_event = NULL; + struct fsnotify_event *new_event; + + pr_debug("%s: list=%p event=%p\n", __func__, list, event); + + + list_for_each_entry_reverse(test_holder, list, event_list) { + if (should_merge(test_holder->event, event)) { + test_event = test_holder->event; + 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); + + /* we hold a reference on new_event from clone_event */ + return new_event; +} + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS +static int fanotify_get_response_from_access(struct fsnotify_group *group, + struct fsnotify_event *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; + + /* userspace responded, convert to something usable */ + spin_lock(&event->lock); + switch (event->response) { + case FAN_ALLOW: + ret = 0; + break; + case FAN_DENY: + default: + 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); + + return ret; +} +#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, + struct fsnotify_mark *vfsmnt_mark, + __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); + + /* 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); + } else if (inode_mark) { + /* + * if the event is for a child and this inode doesn't care about + * events on the child, don't send it! + */ + if ((event_mask & FS_EVENT_ON_CHILD) && + !(inode_mark->mask & FS_EVENT_ON_CHILD)) + return false; + marks_mask = inode_mark->mask; + marks_ignored_mask = inode_mark->ignored_mask; + } else if (vfsmnt_mark) { + marks_mask = vfsmnt_mark->mask; + marks_ignored_mask = vfsmnt_mark->ignored_mask; + } else { + 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 = fanotify_free_group_priv, + .free_event_priv = NULL, + .freeing_mark = NULL, +}; diff --git a/ANDROID_3.4.5/fs/notify/fanotify/fanotify_user.c b/ANDROID_3.4.5/fs/notify/fanotify/fanotify_user.c new file mode 100644 index 00000000..3568c8a8 --- /dev/null +++ b/ANDROID_3.4.5/fs/notify/fanotify/fanotify_user.c @@ -0,0 +1,893 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "../../mount.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; +static struct kmem_cache *fanotify_response_event_cache __read_mostly; + +struct fanotify_response_event { + struct list_head list; + __s32 fd; + struct fsnotify_event *event; +}; + +/* + * 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, + 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 { + fd_install(client_fd, new_file); + } + + return client_fd; +} + +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); + 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 ret; +} + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS +static struct fanotify_response_event *dequeue_re(struct fsnotify_group *group, + __s32 fd) +{ + struct fanotify_response_event *re, *return_re = NULL; + + mutex_lock(&group->fanotify_data.access_mutex); + list_for_each_entry(re, &group->fanotify_data.access_list, list) { + if (re->fd != fd) + continue; + + list_del_init(&re->list); + return_re = re; + break; + } + mutex_unlock(&group->fanotify_data.access_mutex); + + pr_debug("%s: found return_re=%p\n", __func__, return_re); + + return return_re; +} + +static int process_access_response(struct fsnotify_group *group, + struct fanotify_response *response_struct) +{ + struct fanotify_response_event *re; + __s32 fd = response_struct->fd; + __u32 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) { + case FAN_ALLOW: + case FAN_DENY: + break; + default: + return -EINVAL; + } + + if (fd < 0) + return -EINVAL; + + re = dequeue_re(group, fd); + if (!re) + return -ENOENT; + + re->event->response = response; + + wake_up(&group->fanotify_data.access_waitq); + + kmem_cache_free(fanotify_response_event_cache, re); + + return 0; +} + +static int prepare_for_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + struct fanotify_response_event *re; + + if (!(event->mask & FAN_ALL_PERM_EVENTS)) + return 0; + + re = kmem_cache_alloc(fanotify_response_event_cache, GFP_KERNEL); + if (!re) + return -ENOMEM; + + re->event = event; + re->fd = fd; + + mutex_lock(&group->fanotify_data.access_mutex); + + 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; + return 0; + } + + list_add_tail(&re->list, &group->fanotify_data.access_list); + mutex_unlock(&group->fanotify_data.access_mutex); + + return 0; +} + +static void remove_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + struct fanotify_response_event *re; + + if (!(event->mask & FAN_ALL_PERM_EVENTS)) + return; + + re = dequeue_re(group, fd); + if (!re) + return; + + BUG_ON(re->event != event); + + kmem_cache_free(fanotify_response_event_cache, re); + + return; +} +#else +static int prepare_for_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + return 0; +} + +static void remove_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + return; +} +#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; + int fd, ret; + + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + + 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, + fanotify_event_metadata.event_len)) + goto out_kill_access_response; + + return fanotify_event_metadata.event_len; + +out_kill_access_response: + remove_access_response(group, event, fd); +out_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; +} + +/* 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 = -ERESTARTSYS; + 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 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_response_event *re, *lre; + + mutex_lock(&group->fanotify_data.access_mutex); + + 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, + re, re->event); + + list_del_init(&re->list); + re->event->response = FAN_ALLOW; + + kmem_cache_free(fanotify_response_event_cache, re); + } + mutex_unlock(&group->fanotify_data.access_mutex); + + wake_up(&group->fanotify_data.access_waitq); +#endif + /* matches the fanotify_init->fsnotify_alloc_group */ + fsnotify_put_group(group); + + 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 = 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 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 & real_mount(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 & 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 = -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 { + __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; +} + +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; + int ret = 0; + + fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); + if (!fsn_mark) { + 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) + goto err; + } + added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); + + if (added & ~real_mount(mnt)->mnt_fsnotify_mask) + fsnotify_recalc_vfsmount_mask(mnt); +err: + fsnotify_put_mark(fsn_mark); + return ret; +} + +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; + 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) { + 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) + goto err; + } + added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); + + if (added & ~inode->i_fsnotify_mask) + fsnotify_recalc_inode_mask(inode); +err: + fsnotify_put_mark(fsn_mark); + return ret; +} + +/* 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)) { + 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) + 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: /* 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 + 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 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_response_event_cache = KMEM_CACHE(fanotify_response_event, + SLAB_PANIC); + + return 0; +} +device_initcall(fanotify_user_setup); -- cgit