On Fri, Oct 15, 2021 at 12:38 AM Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx> wrote: > > Instead of failing, encode an invalid file handle in fanotify_encode_fh > if no inode is provided. This bogus file handle will be reported by > FAN_FS_ERROR for non-inode errors. > > Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx> Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx> > > --- > Changes since v6: > - Use FILEID_ROOT as the internal value (jan) > - Create an empty FH (jan) > > Changes since v5: > - Preserve flags initialization (jan) > - Add BUILD_BUG_ON (amir) > - Require minimum of FANOTIFY_NULL_FH_LEN for fh_len(amir) > - Improve comment to explain the null FH length (jan) > - Simplify logic > --- > fs/notify/fanotify/fanotify.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c > index ec84fee7ad01..c64d61b673ca 100644 > --- a/fs/notify/fanotify/fanotify.c > +++ b/fs/notify/fanotify/fanotify.c > @@ -370,8 +370,14 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, > fh->type = FILEID_ROOT; > fh->len = 0; > fh->flags = 0; > + > + /* > + * Invalid FHs are used by FAN_FS_ERROR for errors not > + * linked to any inode. The f_handle won't be reported > + * back to userspace. > + */ > if (!inode) > - return 0; > + goto out; > > /* > * !gpf means preallocated variable size fh, but fh_len could > @@ -403,6 +409,7 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, > fh->type = type; > fh->len = fh_len; > > +out: > /* > * Mix fh into event merge key. Hash might be NULL in case of > * unhashed FID events (i.e. FAN_FS_ERROR). > -- > 2.33.0 >
