1 files changed, 119 insertions, 38 deletions

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 6facdf476255..559bc1e9926d 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -30,6 +30,7 @@
 #define FANOTIFY_DEFAULT_MAX_EVENTS	16384
 #define FANOTIFY_OLD_DEFAULT_MAX_MARKS	8192
 #define FANOTIFY_DEFAULT_MAX_GROUPS	128
+#define FANOTIFY_DEFAULT_FEE_POOL_SIZE	32
 
 /*
  * Legacy fanotify marks limits (8192) is per group and we introduced a tunable
@@ -114,6 +115,8 @@ struct kmem_cache *fanotify_perm_event_cachep __read_mostly;
 	(sizeof(struct fanotify_event_info_fid) + sizeof(struct file_handle))
 #define FANOTIFY_PIDFD_INFO_HDR_LEN \
 	sizeof(struct fanotify_event_info_pidfd)
+#define FANOTIFY_ERROR_INFO_LEN \
+	(sizeof(struct fanotify_event_info_error))
 
 static int fanotify_fid_info_len(int fh_len, int name_len)
 {
@@ -126,17 +129,26 @@ static int fanotify_fid_info_len(int fh_len, int name_len)
 		       FANOTIFY_EVENT_ALIGN);
 }
 
-static int fanotify_event_info_len(unsigned int info_mode,
-				   struct fanotify_event *event)
+static size_t fanotify_event_len(unsigned int info_mode,
+				 struct fanotify_event *event)
 {
-	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;
+	size_t event_len = FAN_EVENT_METADATA_LEN;
+	struct fanotify_info *info;
+	int dir_fh_len;
+	int fh_len;
 	int dot_len = 0;
 
-	if (dir_fh_len) {
-		info_len += fanotify_fid_info_len(dir_fh_len, info->name_len);
+	if (!info_mode)
+		return event_len;
+
+	if (fanotify_is_error_event(event->mask))
+		event_len += FANOTIFY_ERROR_INFO_LEN;
+
+	info = fanotify_event_info(event);
+
+	if (fanotify_event_has_dir_fh(event)) {
+		dir_fh_len = fanotify_event_dir_fh_len(event);
+		event_len += fanotify_fid_info_len(dir_fh_len, info->name_len);
 	} else if ((info_mode & FAN_REPORT_NAME) &&
 		   (event->mask & FAN_ONDIR)) {
 		/*
@@ -147,12 +159,14 @@ static int fanotify_event_info_len(unsigned int info_mode,
 	}
 
 	if (info_mode & FAN_REPORT_PIDFD)
-		info_len += FANOTIFY_PIDFD_INFO_HDR_LEN;
+		event_len += FANOTIFY_PIDFD_INFO_HDR_LEN;
 
-	if (fh_len)
-		info_len += fanotify_fid_info_len(fh_len, dot_len);
+	if (fanotify_event_has_object_fh(event)) {
+		fh_len = fanotify_event_object_fh_len(event);
+		event_len += fanotify_fid_info_len(fh_len, dot_len);
+	}
 
-	return info_len;
+	return event_len;
 }
 
 /*
@@ -181,7 +195,7 @@ static void fanotify_unhash_event(struct fsnotify_group *group,
 static struct fanotify_event *get_one_event(struct fsnotify_group *group,
 					    size_t count)
 {
-	size_t event_size = FAN_EVENT_METADATA_LEN;
+	size_t event_size;
 	struct fanotify_event *event = NULL;
 	struct fsnotify_event *fsn_event;
 	unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES);
@@ -194,8 +208,7 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group,
 		goto out;
 
 	event = FANOTIFY_E(fsn_event);
-	if (info_mode)
-		event_size += fanotify_event_info_len(info_mode, event);
+	event_size = fanotify_event_len(info_mode, event);
 
 	if (event_size > count) {
 		event = ERR_PTR(-EINVAL);
@@ -316,6 +329,28 @@ static int process_access_response(struct fsnotify_group *group,
 	return -ENOENT;
 }
 
+static size_t copy_error_info_to_user(struct fanotify_event *event,
+				      char __user *buf, int count)
+{
+	struct fanotify_event_info_error info;
+	struct fanotify_error_event *fee = FANOTIFY_EE(event);
+
+	info.hdr.info_type = FAN_EVENT_INFO_TYPE_ERROR;
+	info.hdr.pad = 0;
+	info.hdr.len = FANOTIFY_ERROR_INFO_LEN;
+
+	if (WARN_ON(count < info.hdr.len))
+		return -EFAULT;
+
+	info.error = fee->error;
+	info.error_count = fee->err_count;
+
+	if (copy_to_user(buf, &info, sizeof(info)))
+		return -EFAULT;
+
+	return info.hdr.len;
+}
+
 static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
 				 int info_type, const char *name,
 				 size_t name_len,
@@ -331,9 +366,6 @@ static int copy_fid_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)
-		return 0;
-
 	if (WARN_ON_ONCE(len < sizeof(info) || len > count))
 		return -EFAULT;
 
@@ -368,6 +400,11 @@ static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
 
 	handle.handle_type = fh->type;
 	handle.handle_bytes = fh_len;
+
+	/* Mangle handle_type for bad file_handle */
+	if (!fh_len)
+		handle.handle_type = FILEID_INVALID;
+
 	if (copy_to_user(buf, &handle, sizeof(handle)))
 		return -EFAULT;
 
@@ -444,7 +481,7 @@ static int copy_info_records_to_user(struct fanotify_event *event,
 	/*
 	 * Event info records order is as follows: dir fid + name, child fid.
 	 */
-	if (fanotify_event_dir_fh_len(event)) {
+	if (fanotify_event_has_dir_fh(event)) {
 		info_type = info->name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME :
 					     FAN_EVENT_INFO_TYPE_DFID;
 		ret = copy_fid_info_to_user(fanotify_event_fsid(event),
@@ -460,7 +497,7 @@ static int copy_info_records_to_user(struct fanotify_event *event,
 		total_bytes += ret;
 	}
 
-	if (fanotify_event_object_fh_len(event)) {
+	if (fanotify_event_has_object_fh(event)) {
 		const char *dot = NULL;
 		int dot_len = 0;
 
@@ -520,6 +557,15 @@ static int copy_info_records_to_user(struct fanotify_event *event,
 		total_bytes += ret;
 	}
 
+	if (fanotify_is_error_event(event->mask)) {
+		ret = copy_error_info_to_user(event, buf, count);
+		if (ret < 0)
+			return ret;
+		buf += ret;
+		count -= ret;
+		total_bytes += ret;
+	}
+
 	return total_bytes;
 }
 
@@ -537,8 +583,7 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 
 	pr_debug("%s: group=%p event=%p\n", __func__, group, event);
 
-	metadata.event_len = FAN_EVENT_METADATA_LEN +
-				fanotify_event_info_len(info_mode, event);
+	metadata.event_len = fanotify_event_len(info_mode, event);
 	metadata.metadata_len = FAN_EVENT_METADATA_LEN;
 	metadata.vers = FANOTIFY_METADATA_VERSION;
 	metadata.reserved = 0;
@@ -1049,6 +1094,15 @@ out_dec_ucounts:
 	return ERR_PTR(ret);
 }
 
+static int fanotify_group_init_error_pool(struct fsnotify_group *group)
+{
+	if (mempool_initialized(&group->fanotify_data.error_events_pool))
+		return 0;
+
+	return mempool_init_kmalloc_pool(&group->fanotify_data.error_events_pool,
+					 FANOTIFY_DEFAULT_FEE_POOL_SIZE,
+					 sizeof(struct fanotify_error_event));
+}
 
 static int fanotify_add_mark(struct fsnotify_group *group,
 			     fsnotify_connp_t *connp, unsigned int type,
@@ -1057,6 +1111,7 @@ static int fanotify_add_mark(struct fsnotify_group *group,
 {
 	struct fsnotify_mark *fsn_mark;
 	__u32 added;
+	int ret = 0;
 
 	mutex_lock(&group->mark_mutex);
 	fsn_mark = fsnotify_find_mark(connp, group);
@@ -1067,13 +1122,26 @@ static int fanotify_add_mark(struct fsnotify_group *group,
 			return PTR_ERR(fsn_mark);
 		}
 	}
+
+	/*
+	 * Error events are pre-allocated per group, only if strictly
+	 * needed (i.e. FAN_FS_ERROR was requested).
+	 */
+	if (!(flags & FAN_MARK_IGNORED_MASK) && (mask & FAN_FS_ERROR)) {
+		ret = fanotify_group_init_error_pool(group);
+		if (ret)
+			goto out;
+	}
+
 	added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
 	if (added & ~fsnotify_conn_mask(fsn_mark->connector))
 		fsnotify_recalc_mask(fsn_mark->connector);
+
+out:
 	mutex_unlock(&group->mark_mutex);
 
 	fsnotify_put_mark(fsn_mark);
-	return 0;
+	return ret;
 }
 
 static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
@@ -1295,16 +1363,15 @@ 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)
+static int fanotify_test_fsid(struct dentry *dentry, __kernel_fsid_t *fsid)
 {
 	__kernel_fsid_t root_fsid;
 	int err;
 
 	/*
-	 * Make sure path is not in filesystem with zero fsid (e.g. tmpfs).
+	 * Make sure dentry is not of a filesystem with zero fsid (e.g. fuse).
 	 */
-	err = vfs_get_fsid(path->dentry, fsid);
+	err = vfs_get_fsid(dentry, fsid);
 	if (err)
 		return err;
 
@@ -1312,10 +1379,10 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
 		return -ENODEV;
 
 	/*
-	 * Make sure path is not inside a filesystem subvolume (e.g. btrfs)
+	 * Make sure dentry is not of 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);
+	err = vfs_get_fsid(dentry->d_sb->s_root, &root_fsid);
 	if (err)
 		return err;
 
@@ -1323,6 +1390,12 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
 	    root_fsid.val[1] != fsid->val[1])
 		return -EXDEV;
 
+	return 0;
+}
+
+/* Check if filesystem can encode a unique fid */
+static int fanotify_test_fid(struct dentry *dentry)
+{
 	/*
 	 * 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
@@ -1330,8 +1403,8 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
 	 * 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)
+	if (!dentry->d_sb->s_export_op ||
+	    !dentry->d_sb->s_export_op->fh_to_dentry)
 		return -EOPNOTSUPP;
 
 	return 0;
@@ -1447,15 +1520,19 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	    group->priority == FS_PRIO_0)
 		goto fput_and_out;
 
+	if (mask & FAN_FS_ERROR &&
+	    mark_type != FAN_MARK_FILESYSTEM)
+		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.
+	 * Events that do not carry enough information to report
+	 * event->fd require a group that supports reporting fid.  Those
+	 * 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 &&
+	if (mask & ~(FANOTIFY_FD_EVENTS|FANOTIFY_EVENT_FLAGS) &&
 	    (!fid_mode || mark_type == FAN_MARK_MOUNT))
 		goto fput_and_out;
 
@@ -1482,7 +1559,11 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	}
 
 	if (fid_mode) {
-		ret = fanotify_test_fid(&path, &__fsid);
+		ret = fanotify_test_fsid(path.dentry, &__fsid);
+		if (ret)
+			goto path_put_and_out;
+
+		ret = fanotify_test_fid(path.dentry);
 		if (ret)
 			goto path_put_and_out;