On Fri, Oct 15, 2021 at 12:39 AM Gabriel Krisman Bertazi
<krisman@xxxxxxxxxxxxx> wrote:
>
> Wire up the FAN_FS_ERROR event in the fanotify_mark syscall, allowing
> user space to request the monitoring of FAN_FS_ERROR events.
>
> These events are limited to filesystem marks, so check it is the
> case in the syscall handler.
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
> ---
> fs/notify/fanotify/fanotify.c | 2 +-
> fs/notify/fanotify/fanotify_user.c | 5 +++++
> include/linux/fanotify.h | 6 +++++-
> 3 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> index 47e28f418711..d449a23d603f 100644
> --- a/fs/notify/fanotify/fanotify.c
> +++ b/fs/notify/fanotify/fanotify.c
> @@ -827,7 +827,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
> BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM);
> BUILD_BUG_ON(FAN_FS_ERROR != FS_ERROR);
>
> - BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19);
> + BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 20);
>
> mask = fanotify_group_event_mask(group, iter_info, mask, data,
> data_type, dir);
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 8f7c2f4ce674..5edfd7e3f356 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -1585,6 +1585,11 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
> fsid = &__fsid;
> }
>
> + if (mask & FAN_FS_ERROR && mark_type != FAN_MARK_FILESYSTEM) {
> + ret = -EINVAL;
> + goto path_put_and_out;
> + }
> +
Please move this up to the section where input args validity is checked
(i.e. before or after FANOTIFY_PERM_EVENTS check).
It is the correct context for this sort of check and ret is already
set to -EINVAL for the entire section.
Thanks,
Amir.
