1 files changed, 165 insertions, 53 deletions

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 63b5dffdca9e..559de311deca 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -64,21 +64,28 @@ static int fanotify_fid_info_len(int fh_len, int name_len)
 	return roundup(FANOTIFY_INFO_HDR_LEN + info_len, FANOTIFY_EVENT_ALIGN);
 }
 
-static int fanotify_event_info_len(struct fanotify_event *event)
+static int fanotify_event_info_len(unsigned int fid_mode,
+				   struct fanotify_event *event)
 {
-	int info_len = 0;
+	struct fanotify_info *info = fanotify_event_info(event);
+	int dir_fh_len = fanotify_event_dir_fh_len(event);
 	int fh_len = fanotify_event_object_fh_len(event);
+	int info_len = 0;
+	int dot_len = 0;
 
-	if (fh_len)
-		info_len += fanotify_fid_info_len(fh_len, 0);
-
-	if (fanotify_event_name_len(event)) {
-		struct fanotify_name_event *fne = FANOTIFY_NE(event);
-
-		info_len += fanotify_fid_info_len(fne->dir_fh.len,
-						  fne->name_len);
+	if (dir_fh_len) {
+		info_len += fanotify_fid_info_len(dir_fh_len, info->name_len);
+	} else if ((fid_mode & FAN_REPORT_NAME) && (event->mask & FAN_ONDIR)) {
+		/*
+		 * With group flag FAN_REPORT_NAME, if name was not recorded in
+		 * event on a directory, we will report the name ".".
+		 */
+		dot_len = 1;
 	}
 
+	if (fh_len)
+		info_len += fanotify_fid_info_len(fh_len, dot_len);
+
 	return info_len;
 }
 
@@ -93,6 +100,7 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group,
 {
 	size_t event_size = FAN_EVENT_METADATA_LEN;
 	struct fanotify_event *event = NULL;
+	unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
 
 	pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
 
@@ -100,8 +108,8 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group,
 	if (fsnotify_notify_queue_is_empty(group))
 		goto out;
 
-	if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
-		event_size += fanotify_event_info_len(
+	if (fid_mode) {
+		event_size += fanotify_event_info_len(fid_mode,
 			FANOTIFY_E(fsnotify_peek_first_event(group)));
 	}
 
@@ -218,7 +226,7 @@ static int process_access_response(struct fsnotify_group *group,
 }
 
 static int copy_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
-			     const char *name, size_t name_len,
+			     int info_type, const char *name, size_t name_len,
 			     char __user *buf, size_t count)
 {
 	struct fanotify_event_info_fid info = { };
@@ -231,7 +239,7 @@ static int copy_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
 	pr_debug("%s: fh_len=%zu name_len=%zu, info_len=%zu, count=%zu\n",
 		 __func__, fh_len, name_len, info_len, count);
 
-	if (!fh_len || (name && !name_len))
+	if (!fh_len)
 		return 0;
 
 	if (WARN_ON_ONCE(len < sizeof(info) || len > count))
@@ -241,8 +249,21 @@ static int copy_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
 	 * Copy event info fid header followed by variable sized file handle
 	 * and optionally followed by variable sized filename.
 	 */
-	info.hdr.info_type = name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME :
-					FAN_EVENT_INFO_TYPE_FID;
+	switch (info_type) {
+	case FAN_EVENT_INFO_TYPE_FID:
+	case FAN_EVENT_INFO_TYPE_DFID:
+		if (WARN_ON_ONCE(name_len))
+			return -EFAULT;
+		break;
+	case FAN_EVENT_INFO_TYPE_DFID_NAME:
+		if (WARN_ON_ONCE(!name || !name_len))
+			return -EFAULT;
+		break;
+	default:
+		return -EFAULT;
+	}
+
+	info.hdr.info_type = info_type;
 	info.hdr.len = len;
 	info.fsid = *fsid;
 	if (copy_to_user(buf, &info, sizeof(info)))
@@ -305,13 +326,16 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 {
 	struct fanotify_event_metadata metadata;
 	struct path *path = fanotify_event_path(event);
+	struct fanotify_info *info = fanotify_event_info(event);
+	unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
 	struct file *f = NULL;
 	int ret, fd = FAN_NOFD;
+	int info_type = 0;
 
 	pr_debug("%s: group=%p event=%p\n", __func__, group, event);
 
 	metadata.event_len = FAN_EVENT_METADATA_LEN +
-					fanotify_event_info_len(event);
+				fanotify_event_info_len(fid_mode, event);
 	metadata.metadata_len = FAN_EVENT_METADATA_LEN;
 	metadata.vers = FANOTIFY_METADATA_VERSION;
 	metadata.reserved = 0;
@@ -346,13 +370,13 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 		fd_install(fd, f);
 
 	/* Event info records order is: dir fid + name, child fid */
-	if (fanotify_event_name_len(event)) {
-		struct fanotify_name_event *fne = FANOTIFY_NE(event);
-
+	if (fanotify_event_dir_fh_len(event)) {
+		info_type = info->name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME :
+					     FAN_EVENT_INFO_TYPE_DFID;
 		ret = copy_info_to_user(fanotify_event_fsid(event),
-					fanotify_event_dir_fh(event),
-					fne->name, fne->name_len,
-					buf, count);
+					fanotify_info_dir_fh(info),
+					info_type, fanotify_info_name(info),
+					info->name_len, buf, count);
 		if (ret < 0)
 			return ret;
 
@@ -361,9 +385,46 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 	}
 
 	if (fanotify_event_object_fh_len(event)) {
+		const char *dot = NULL;
+		int dot_len = 0;
+
+		if (fid_mode == FAN_REPORT_FID || info_type) {
+			/*
+			 * With only group flag FAN_REPORT_FID only type FID is
+			 * reported. Second info record type is always FID.
+			 */
+			info_type = FAN_EVENT_INFO_TYPE_FID;
+		} else if ((fid_mode & FAN_REPORT_NAME) &&
+			   (event->mask & FAN_ONDIR)) {
+			/*
+			 * With group flag FAN_REPORT_NAME, if name was not
+			 * recorded in an event on a directory, report the
+			 * name "." with info type DFID_NAME.
+			 */
+			info_type = FAN_EVENT_INFO_TYPE_DFID_NAME;
+			dot = ".";
+			dot_len = 1;
+		} else if ((event->mask & ALL_FSNOTIFY_DIRENT_EVENTS) ||
+			   (event->mask & FAN_ONDIR)) {
+			/*
+			 * With group flag FAN_REPORT_DIR_FID, a single info
+			 * record has type DFID for directory entry modification
+			 * event and for event on a directory.
+			 */
+			info_type = FAN_EVENT_INFO_TYPE_DFID;
+		} else {
+			/*
+			 * With group flags FAN_REPORT_DIR_FID|FAN_REPORT_FID,
+			 * a single info record has type FID for event on a
+			 * non-directory, when there is no directory to report.
+			 * For example, on FAN_DELETE_SELF event.
+			 */
+			info_type = FAN_EVENT_INFO_TYPE_FID;
+		}
+
 		ret = copy_info_to_user(fanotify_event_fsid(event),
 					fanotify_event_object_fh(event),
-					NULL, 0, buf, count);
+					info_type, dot, dot_len, buf, count);
 		if (ret < 0)
 			return ret;
 
@@ -412,6 +473,11 @@ static ssize_t fanotify_read(struct file *file, char __user *buf,
 
 	add_wait_queue(&group->notification_waitq, &wait);
 	while (1) {
+		/*
+		 * User can supply arbitrarily large buffer. Avoid softlockups
+		 * in case there are lots of available events.
+		 */
+		cond_resched();
 		event = get_one_event(group, count);
 		if (IS_ERR(event)) {
 			ret = PTR_ERR(event);
@@ -651,12 +717,13 @@ out:
 }
 
 static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
-					    __u32 mask,
-					    unsigned int flags,
-					    int *destroy)
+					    __u32 mask, unsigned int flags,
+					    __u32 umask, int *destroy)
 {
 	__u32 oldmask = 0;
 
+	/* umask bits cannot be removed by user */
+	mask &= ~umask;
 	spin_lock(&fsn_mark->lock);
 	if (!(flags & FAN_MARK_IGNORED_MASK)) {
 		oldmask = fsn_mark->mask;
@@ -664,7 +731,13 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 	} else {
 		fsn_mark->ignored_mask &= ~mask;
 	}
-	*destroy = !(fsn_mark->mask | fsn_mark->ignored_mask);
+	/*
+	 * We need to keep the mark around even if remaining mask cannot
+	 * result in any events (e.g. mask == FAN_ONDIR) to support incremenal
+	 * changes to the mask.
+	 * Destroy mark when only umask bits remain.
+	 */
+	*destroy = !((fsn_mark->mask | fsn_mark->ignored_mask) & ~umask);
 	spin_unlock(&fsn_mark->lock);
 
 	return mask & oldmask;
@@ -672,7 +745,7 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 
 static int fanotify_remove_mark(struct fsnotify_group *group,
 				fsnotify_connp_t *connp, __u32 mask,
-				unsigned int flags)
+				unsigned int flags, __u32 umask)
 {
 	struct fsnotify_mark *fsn_mark = NULL;
 	__u32 removed;
@@ -686,7 +759,7 @@ static int fanotify_remove_mark(struct fsnotify_group *group,
 	}
 
 	removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags,
-						 &destroy_mark);
+						 umask, &destroy_mark);
 	if (removed & fsnotify_conn_mask(fsn_mark->connector))
 		fsnotify_recalc_mask(fsn_mark->connector);
 	if (destroy_mark)
@@ -702,25 +775,26 @@ static int fanotify_remove_mark(struct fsnotify_group *group,
 
 static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
 					 struct vfsmount *mnt, __u32 mask,
-					 unsigned int flags)
+					 unsigned int flags, __u32 umask)
 {
 	return fanotify_remove_mark(group, &real_mount(mnt)->mnt_fsnotify_marks,
-				    mask, flags);
+				    mask, flags, umask);
 }
 
 static int fanotify_remove_sb_mark(struct fsnotify_group *group,
-				      struct super_block *sb, __u32 mask,
-				      unsigned int flags)
+				   struct super_block *sb, __u32 mask,
+				   unsigned int flags, __u32 umask)
 {
-	return fanotify_remove_mark(group, &sb->s_fsnotify_marks, mask, flags);
+	return fanotify_remove_mark(group, &sb->s_fsnotify_marks, mask,
+				    flags, umask);
 }
 
 static int fanotify_remove_inode_mark(struct fsnotify_group *group,
 				      struct inode *inode, __u32 mask,
-				      unsigned int flags)
+				      unsigned int flags, __u32 umask)
 {
 	return fanotify_remove_mark(group, &inode->i_fsnotify_marks, mask,
-				    flags);
+				    flags, umask);
 }
 
 static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
@@ -831,13 +905,28 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group,
 				 FSNOTIFY_OBJ_TYPE_INODE, mask, flags, fsid);
 }
 
+static struct fsnotify_event *fanotify_alloc_overflow_event(void)
+{
+	struct fanotify_event *oevent;
+
+	oevent = kmalloc(sizeof(*oevent), GFP_KERNEL_ACCOUNT);
+	if (!oevent)
+		return NULL;
+
+	fanotify_init_event(oevent, 0, FS_Q_OVERFLOW);
+	oevent->type = FANOTIFY_EVENT_TYPE_OVERFLOW;
+
+	return &oevent->fse;
+}
+
 /* 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 *oevent;
+	unsigned int fid_mode = flags & FANOTIFY_FID_BITS;
+	unsigned int class = flags & FANOTIFY_CLASS_BITS;
 
 	pr_debug("%s: flags=%x event_f_flags=%x\n",
 		 __func__, flags, event_f_flags);
@@ -864,8 +953,14 @@ 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)
+	if (fid_mode && class != FAN_CLASS_NOTIF)
+		return -EINVAL;
+
+	/*
+	 * Child name is reported with parent fid so requires dir fid.
+	 * We can report both child fid and dir fid with or without name.
+	 */
+	if ((fid_mode & FAN_REPORT_NAME) && !(fid_mode & FAN_REPORT_DIR_FID))
 		return -EINVAL;
 
 	user = get_current_user();
@@ -892,20 +987,18 @@ 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,
-				      FSNOTIFY_EVENT_NONE, NULL, NULL);
-	if (unlikely(!oevent)) {
+	group->overflow_event = fanotify_alloc_overflow_event();
+	if (unlikely(!group->overflow_event)) {
 		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;
 	init_waitqueue_head(&group->fanotify_data.access_waitq);
 	INIT_LIST_HEAD(&group->fanotify_data.access_list);
-	switch (flags & FANOTIFY_CLASS_BITS) {
+	switch (class) {
 	case FAN_CLASS_NOTIF:
 		group->priority = FS_PRIO_0;
 		break;
@@ -1024,7 +1117,9 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	__kernel_fsid_t __fsid, *fsid = NULL;
 	u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;
 	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
-	unsigned int obj_type;
+	bool ignored = flags & FAN_MARK_IGNORED_MASK;
+	unsigned int obj_type, fid_mode;
+	u32 umask = 0;
 	int ret;
 
 	pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
@@ -1071,6 +1166,10 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	if (mask & ~valid_mask)
 		return -EINVAL;
 
+	/* Event flags (ONDIR, ON_CHILD) are meaningless in ignored mask */
+	if (ignored)
+		mask &= ~FANOTIFY_EVENT_FLAGS;
+
 	f = fdget(fanotify_fd);
 	if (unlikely(!f.file))
 		return -EBADF;
@@ -1097,9 +1196,9 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	 * 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.
 	 */
+	fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
 	if (mask & FANOTIFY_INODE_EVENTS &&
-	    (!FAN_GROUP_FLAG(group, FAN_REPORT_FID) ||
-	     mark_type == FAN_MARK_MOUNT))
+	    (!fid_mode || mark_type == FAN_MARK_MOUNT))
 		goto fput_and_out;
 
 	if (flags & FAN_MARK_FLUSH) {
@@ -1124,7 +1223,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 			goto path_put_and_out;
 	}
 
-	if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+	if (fid_mode) {
 		ret = fanotify_test_fid(&path, &__fsid);
 		if (ret)
 			goto path_put_and_out;
@@ -1138,6 +1237,19 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	else
 		mnt = path.mnt;
 
+	/* Mask out FAN_EVENT_ON_CHILD flag for sb/mount/non-dir marks */
+	if (mnt || !S_ISDIR(inode->i_mode)) {
+		mask &= ~FAN_EVENT_ON_CHILD;
+		umask = FAN_EVENT_ON_CHILD;
+		/*
+		 * If group needs to report parent fid, register for getting
+		 * events with parent/name info for non-directory.
+		 */
+		if ((fid_mode & FAN_REPORT_DIR_FID) &&
+		    (flags & FAN_MARK_ADD) && !ignored)
+			mask |= FAN_EVENT_ON_CHILD;
+	}
+
 	/* create/update an inode mark */
 	switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) {
 	case FAN_MARK_ADD:
@@ -1154,13 +1266,13 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	case FAN_MARK_REMOVE:
 		if (mark_type == FAN_MARK_MOUNT)
 			ret = fanotify_remove_vfsmount_mark(group, mnt, mask,
-							    flags);
+							    flags, umask);
 		else if (mark_type == FAN_MARK_FILESYSTEM)
 			ret = fanotify_remove_sb_mark(group, mnt->mnt_sb, mask,
-						      flags);
+						      flags, umask);
 		else
 			ret = fanotify_remove_inode_mark(group, inode, mask,
-							 flags);
+							 flags, umask);
 		break;
 	default:
 		ret = -EINVAL;
@@ -1203,7 +1315,7 @@ COMPAT_SYSCALL_DEFINE6(fanotify_mark,
  */
 static int __init fanotify_user_setup(void)
 {
-	BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 8);
+	BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 10);
 	BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9);
 
 	fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,