diff options
Diffstat (limited to 'fs/notify/fanotify/fanotify_user.c')
-rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 373 |
1 files changed, 255 insertions, 118 deletions
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 9c870b0d2b56..56992b32c6bb 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -17,6 +17,8 @@ #include <linux/compat.h> #include <linux/sched/signal.h> #include <linux/memcontrol.h> +#include <linux/statfs.h> +#include <linux/exportfs.h> #include <asm/ioctls.h> @@ -47,33 +49,55 @@ 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; +#define FANOTIFY_EVENT_ALIGN 4 + +static int fanotify_event_info_len(struct fanotify_event *event) +{ + if (!fanotify_event_has_fid(event)) + return 0; + + return roundup(sizeof(struct fanotify_event_info_fid) + + sizeof(struct file_handle) + event->fh_len, + FANOTIFY_EVENT_ALIGN); +} + /* * 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. + * is not large enough. When permission event is dequeued, its state is + * updated accordingly. */ static struct fsnotify_event *get_one_event(struct fsnotify_group *group, size_t count) { - assert_spin_locked(&group->notification_lock); + size_t event_size = FAN_EVENT_METADATA_LEN; + struct fsnotify_event *fsn_event = NULL; pr_debug("%s: group=%p count=%zd\n", __func__, group, count); + spin_lock(&group->notification_lock); if (fsnotify_notify_queue_is_empty(group)) - return NULL; + goto out; - if (FAN_EVENT_METADATA_LEN > count) - return ERR_PTR(-EINVAL); + if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) { + event_size += fanotify_event_info_len( + FANOTIFY_E(fsnotify_peek_first_event(group))); + } - /* held the notification_lock the whole time, so this is the - * same event we peeked above */ - return fsnotify_remove_first_event(group); + if (event_size > count) { + fsn_event = ERR_PTR(-EINVAL); + goto out; + } + fsn_event = fsnotify_remove_first_event(group); + if (fanotify_is_perm_event(FANOTIFY_E(fsn_event)->mask)) + FANOTIFY_PE(fsn_event)->state = FAN_EVENT_REPORTED; +out: + spin_unlock(&group->notification_lock); + return fsn_event; } static int create_fd(struct fsnotify_group *group, - struct fanotify_event_info *event, + struct fanotify_event *event, struct file **file) { int client_fd; @@ -114,62 +138,32 @@ static int create_fd(struct fsnotify_group *group, 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 & FANOTIFY_OUTGOING_EVENTS; - metadata->pid = pid_vnr(event->pid); - 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; -} - -static struct fanotify_perm_event_info *dequeue_event( - struct fsnotify_group *group, int fd) +/* + * Finish processing of permission event by setting it to ANSWERED state and + * drop group->notification_lock. + */ +static void finish_permission_event(struct fsnotify_group *group, + struct fanotify_perm_event *event, + unsigned int response) + __releases(&group->notification_lock) { - 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; + bool destroy = false; - list_del_init(&event->fae.fse.list); - return_e = event; - break; - } + assert_spin_locked(&group->notification_lock); + event->response = response; + if (event->state == FAN_EVENT_CANCELED) + destroy = true; + else + event->state = FAN_EVENT_ANSWERED; spin_unlock(&group->notification_lock); - - pr_debug("%s: found return_re=%p\n", __func__, return_e); - - return return_e; + if (destroy) + fsnotify_destroy_event(group, &event->fae.fse); } static int process_access_response(struct fsnotify_group *group, struct fanotify_response *response_struct) { - struct fanotify_perm_event_info *event; + struct fanotify_perm_event *event; int fd = response_struct->fd; int response = response_struct->response; @@ -194,48 +188,115 @@ static int process_access_response(struct fsnotify_group *group, if ((response & FAN_AUDIT) && !FAN_GROUP_FLAG(group, FAN_ENABLE_AUDIT)) return -EINVAL; - event = dequeue_event(group, fd); - if (!event) - return -ENOENT; + spin_lock(&group->notification_lock); + list_for_each_entry(event, &group->fanotify_data.access_list, + fae.fse.list) { + if (event->fd != fd) + continue; - event->response = response; - wake_up(&group->fanotify_data.access_waitq); + list_del_init(&event->fae.fse.list); + finish_permission_event(group, event, response); + wake_up(&group->fanotify_data.access_waitq); + return 0; + } + spin_unlock(&group->notification_lock); + + return -ENOENT; +} + +static int copy_fid_to_user(struct fanotify_event *event, char __user *buf) +{ + struct fanotify_event_info_fid info = { }; + struct file_handle handle = { }; + size_t fh_len = event->fh_len; + size_t len = fanotify_event_info_len(event); + + if (!len) + return 0; + + if (WARN_ON_ONCE(len < sizeof(info) + sizeof(handle) + fh_len)) + return -EFAULT; + + /* Copy event info fid header followed by vaiable sized file handle */ + info.hdr.info_type = FAN_EVENT_INFO_TYPE_FID; + info.hdr.len = len; + info.fsid = event->fid.fsid; + if (copy_to_user(buf, &info, sizeof(info))) + return -EFAULT; + + buf += sizeof(info); + len -= sizeof(info); + handle.handle_type = event->fh_type; + handle.handle_bytes = fh_len; + if (copy_to_user(buf, &handle, sizeof(handle))) + return -EFAULT; + + buf += sizeof(handle); + len -= sizeof(handle); + if (copy_to_user(buf, fanotify_event_fh(event), fh_len)) + return -EFAULT; + + /* Pad with 0's */ + buf += fh_len; + len -= fh_len; + WARN_ON_ONCE(len < 0 || len >= FANOTIFY_EVENT_ALIGN); + if (len > 0 && clear_user(buf, len)) + return -EFAULT; return 0; } static ssize_t copy_event_to_user(struct fsnotify_group *group, - struct fsnotify_event *event, + struct fsnotify_event *fsn_event, char __user *buf, size_t count) { - 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; + struct fanotify_event_metadata metadata; + struct fanotify_event *event; + struct file *f = NULL; + int ret, fd = FAN_NOFD; + + pr_debug("%s: group=%p event=%p\n", __func__, group, fsn_event); + + event = container_of(fsn_event, struct fanotify_event, 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 = event->mask & FANOTIFY_OUTGOING_EVENTS; + metadata.pid = pid_vnr(event->pid); + + if (fanotify_event_has_path(event)) { + fd = create_fd(group, event, &f); + if (fd < 0) + return fd; + } else if (fanotify_event_has_fid(event)) { + metadata.event_len += fanotify_event_info_len(event); + } + metadata.fd = fd; - fd = fanotify_event_metadata.fd; ret = -EFAULT; /* * Sanity check copy size in case get_one_event() and * fill_event_metadata() event_len sizes ever get out of sync. */ - if (WARN_ON_ONCE(fanotify_event_metadata.event_len > count)) + if (WARN_ON_ONCE(metadata.event_len > count)) goto out_close_fd; - if (copy_to_user(buf, &fanotify_event_metadata, - fanotify_event_metadata.event_len)) + + if (copy_to_user(buf, &metadata, FAN_EVENT_METADATA_LEN)) goto out_close_fd; if (fanotify_is_perm_event(event->mask)) - FANOTIFY_PE(event)->fd = fd; + FANOTIFY_PE(fsn_event)->fd = fd; - if (fd != FAN_NOFD) + if (fanotify_event_has_path(event)) { fd_install(fd, f); - return fanotify_event_metadata.event_len; + } else if (fanotify_event_has_fid(event)) { + ret = copy_fid_to_user(event, buf + FAN_EVENT_METADATA_LEN); + if (ret < 0) + return ret; + } + + return metadata.event_len; out_close_fd: if (fd != FAN_NOFD) { @@ -276,10 +337,7 @@ static ssize_t fanotify_read(struct file *file, char __user *buf, 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; @@ -316,11 +374,13 @@ static ssize_t fanotify_read(struct file *file, char __user *buf, * Permission events get queued to wait for response. Other * events can be destroyed now. */ - if (!fanotify_is_perm_event(kevent->mask)) { + if (!fanotify_is_perm_event(FANOTIFY_E(kevent)->mask)) { fsnotify_destroy_event(group, kevent); } else { if (ret <= 0) { - FANOTIFY_PE(kevent)->response = FAN_DENY; + spin_lock(&group->notification_lock); + finish_permission_event(group, + FANOTIFY_PE(kevent), FAN_DENY); wake_up(&group->fanotify_data.access_waitq); } else { spin_lock(&group->notification_lock); @@ -370,7 +430,7 @@ 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_perm_event_info *event, *next; + struct fanotify_perm_event *event; struct fsnotify_event *fsn_event; /* @@ -385,13 +445,12 @@ static int fanotify_release(struct inode *ignored, struct file *file) * 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); - + while (!list_empty(&group->fanotify_data.access_list)) { + event = list_first_entry(&group->fanotify_data.access_list, + struct fanotify_perm_event, fae.fse.list); list_del_init(&event->fae.fse.list); - event->response = FAN_ALLOW; + finish_permission_event(group, event, FAN_ALLOW); + spin_lock(&group->notification_lock); } /* @@ -401,13 +460,14 @@ static int fanotify_release(struct inode *ignored, struct file *file) */ while (!fsnotify_notify_queue_is_empty(group)) { fsn_event = fsnotify_remove_first_event(group); - if (!(fsn_event->mask & FANOTIFY_PERM_EVENTS)) { + if (!(FANOTIFY_E(fsn_event)->mask & FANOTIFY_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; + finish_permission_event(group, FANOTIFY_PE(fsn_event), + FAN_ALLOW); } + spin_lock(&group->notification_lock); } spin_unlock(&group->notification_lock); @@ -598,7 +658,8 @@ static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, fsnotify_connp_t *connp, - unsigned int type) + unsigned int type, + __kernel_fsid_t *fsid) { struct fsnotify_mark *mark; int ret; @@ -611,7 +672,7 @@ static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, return ERR_PTR(-ENOMEM); fsnotify_init_mark(mark, group); - ret = fsnotify_add_mark_locked(mark, connp, type, 0); + ret = fsnotify_add_mark_locked(mark, connp, type, 0, fsid); if (ret) { fsnotify_put_mark(mark); return ERR_PTR(ret); @@ -623,7 +684,8 @@ static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, static int fanotify_add_mark(struct fsnotify_group *group, fsnotify_connp_t *connp, unsigned int type, - __u32 mask, unsigned int flags) + __u32 mask, unsigned int flags, + __kernel_fsid_t *fsid) { struct fsnotify_mark *fsn_mark; __u32 added; @@ -631,7 +693,7 @@ static int fanotify_add_mark(struct fsnotify_group *group, mutex_lock(&group->mark_mutex); fsn_mark = fsnotify_find_mark(connp, group); if (!fsn_mark) { - fsn_mark = fanotify_add_new_mark(group, connp, type); + fsn_mark = fanotify_add_new_mark(group, connp, type, fsid); if (IS_ERR(fsn_mark)) { mutex_unlock(&group->mark_mutex); return PTR_ERR(fsn_mark); @@ -648,23 +710,23 @@ static int fanotify_add_mark(struct fsnotify_group *group, static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, struct vfsmount *mnt, __u32 mask, - unsigned int flags) + unsigned int flags, __kernel_fsid_t *fsid) { return fanotify_add_mark(group, &real_mount(mnt)->mnt_fsnotify_marks, - FSNOTIFY_OBJ_TYPE_VFSMOUNT, mask, flags); + FSNOTIFY_OBJ_TYPE_VFSMOUNT, mask, flags, fsid); } static int fanotify_add_sb_mark(struct fsnotify_group *group, - struct super_block *sb, __u32 mask, - unsigned int flags) + struct super_block *sb, __u32 mask, + unsigned int flags, __kernel_fsid_t *fsid) { return fanotify_add_mark(group, &sb->s_fsnotify_marks, - FSNOTIFY_OBJ_TYPE_SB, mask, flags); + FSNOTIFY_OBJ_TYPE_SB, mask, flags, fsid); } static int fanotify_add_inode_mark(struct fsnotify_group *group, struct inode *inode, __u32 mask, - unsigned int flags) + unsigned int flags, __kernel_fsid_t *fsid) { pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); @@ -679,7 +741,7 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group, return 0; return fanotify_add_mark(group, &inode->i_fsnotify_marks, - FSNOTIFY_OBJ_TYPE_INODE, mask, flags); + FSNOTIFY_OBJ_TYPE_INODE, mask, flags, fsid); } /* fanotify syscalls */ @@ -688,7 +750,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) struct fsnotify_group *group; int f_flags, fd; struct user_struct *user; - struct fanotify_event_info *oevent; + struct fanotify_event *oevent; pr_debug("%s: flags=%x event_f_flags=%x\n", __func__, flags, event_f_flags); @@ -715,6 +777,10 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) return -EINVAL; } + if ((flags & FAN_REPORT_FID) && + (flags & FANOTIFY_CLASS_BITS) != FAN_CLASS_NOTIF) + return -EINVAL; + user = get_current_user(); if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) { free_uid(user); @@ -739,7 +805,8 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) atomic_inc(&user->fanotify_listeners); group->memcg = get_mem_cgroup_from_mm(current->mm); - oevent = fanotify_alloc_event(group, NULL, FS_Q_OVERFLOW, NULL); + oevent = fanotify_alloc_event(group, NULL, FS_Q_OVERFLOW, NULL, + FSNOTIFY_EVENT_NONE, NULL); if (unlikely(!oevent)) { fd = -ENOMEM; goto out_destroy_group; @@ -801,6 +868,48 @@ out_destroy_group: return fd; } +/* Check if filesystem can encode a unique fid */ +static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid) +{ + __kernel_fsid_t root_fsid; + int err; + + /* + * Make sure path is not in filesystem with zero fsid (e.g. tmpfs). + */ + err = vfs_get_fsid(path->dentry, fsid); + if (err) + return err; + + if (!fsid->val[0] && !fsid->val[1]) + return -ENODEV; + + /* + * Make sure path is not inside a filesystem subvolume (e.g. btrfs) + * which uses a different fsid than sb root. + */ + err = vfs_get_fsid(path->dentry->d_sb->s_root, &root_fsid); + if (err) + return err; + + if (root_fsid.val[0] != fsid->val[0] || + root_fsid.val[1] != fsid->val[1]) + return -EXDEV; + + /* + * We need to make sure that the file system supports at least + * encoding a file handle so user can use name_to_handle_at() to + * compare fid returned with event to the file handle of watched + * objects. However, name_to_handle_at() requires that the + * filesystem also supports decoding file handles. + */ + if (!path->dentry->d_sb->s_export_op || + !path->dentry->d_sb->s_export_op->fh_to_dentry) + return -EOPNOTSUPP; + + return 0; +} + static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, int dfd, const char __user *pathname) { @@ -809,6 +918,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, struct fsnotify_group *group; struct fd f; struct path path; + __kernel_fsid_t __fsid, *fsid = NULL; u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS; unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS; int ret; @@ -871,6 +981,18 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, group->priority == FS_PRIO_0) goto fput_and_out; + /* + * Events with data type inode do not carry enough information to report + * event->fd, so we do not allow setting a mask for inode events unless + * group supports reporting fid. + * inode events are not supported on a mount mark, because they do not + * carry enough information (i.e. path) to be filtered by mount point. + */ + if (mask & FANOTIFY_INODE_EVENTS && + (!FAN_GROUP_FLAG(group, FAN_REPORT_FID) || + mark_type == FAN_MARK_MOUNT)) + goto fput_and_out; + if (flags & FAN_MARK_FLUSH) { ret = 0; if (mark_type == FAN_MARK_MOUNT) @@ -886,6 +1008,14 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, if (ret) goto fput_and_out; + if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) { + ret = fanotify_test_fid(&path, &__fsid); + if (ret) + goto path_put_and_out; + + fsid = &__fsid; + } + /* inode held in place by reference to path; group by fget on fd */ if (mark_type == FAN_MARK_INODE) inode = path.dentry->d_inode; @@ -896,24 +1026,31 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) { case FAN_MARK_ADD: if (mark_type == FAN_MARK_MOUNT) - ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); + ret = fanotify_add_vfsmount_mark(group, mnt, mask, + flags, fsid); else if (mark_type == FAN_MARK_FILESYSTEM) - ret = fanotify_add_sb_mark(group, mnt->mnt_sb, mask, flags); + ret = fanotify_add_sb_mark(group, mnt->mnt_sb, mask, + flags, fsid); else - ret = fanotify_add_inode_mark(group, inode, mask, flags); + ret = fanotify_add_inode_mark(group, inode, mask, + flags, fsid); break; case FAN_MARK_REMOVE: if (mark_type == FAN_MARK_MOUNT) - ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); + ret = fanotify_remove_vfsmount_mark(group, mnt, mask, + flags); else if (mark_type == FAN_MARK_FILESYSTEM) - ret = fanotify_remove_sb_mark(group, mnt->mnt_sb, mask, flags); + ret = fanotify_remove_sb_mark(group, mnt->mnt_sb, mask, + flags); else - ret = fanotify_remove_inode_mark(group, inode, mask, flags); + ret = fanotify_remove_inode_mark(group, inode, mask, + flags); break; default: ret = -EINVAL; } +path_put_and_out: path_put(&path); fput_and_out: fdput(f); @@ -950,15 +1087,15 @@ COMPAT_SYSCALL_DEFINE6(fanotify_mark, */ static int __init fanotify_user_setup(void) { - BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 7); + BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 8); BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9); fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC|SLAB_ACCOUNT); - fanotify_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC); + fanotify_event_cachep = KMEM_CACHE(fanotify_event, SLAB_PANIC); if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) { fanotify_perm_event_cachep = - KMEM_CACHE(fanotify_perm_event_info, SLAB_PANIC); + KMEM_CACHE(fanotify_perm_event, SLAB_PANIC); } return 0; |