[PATCH v9 24/31] fanotify: Report fid entry even for zero-length file_handle
From: Gabriel Krisman Bertazi <hidden>
Date: 2021-10-25 20:10:08
Also in:
linux-api, linux-fsdevel
Subsystem:
fanotify, filesystems (vfs and infrastructure), fsnotify: filesystem notification infrastructure, the rest · Maintainers:
Jan Kara, Alexander Viro, Christian Brauner, Linus Torvalds
Non-inode errors will reported with an empty file_handle. In preparation for that, allow some events to print the FID record even if there isn't any file_handle encoded Even though FILEID_ROOT is used internally, make zero-length file handles be reported as FILEID_INVALID. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Gabriel Krisman Bertazi <redacted> --- Changes since v8: - Move fanotify_event_has_object_fh check here (jan) --- fs/notify/fanotify/fanotify.h | 3 +++ fs/notify/fanotify/fanotify_user.c | 8 +++++--- 2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 80af269eebb8..f51ab6e556e8 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h@@ -266,6 +266,9 @@ static inline int fanotify_event_dir_fh_len(struct fanotify_event *event) static inline bool fanotify_event_has_object_fh(struct fanotify_event *event) { + /* For error events, even zeroed fh are reported. */ + if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR) + return true; return fanotify_event_object_fh_len(event) > 0; }
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index a9b5c36ee49e..ff4a7373f7a5 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c@@ -339,9 +339,6 @@ 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;
@@ -376,6 +373,11 @@ 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;
--
2.33.0