Re: [PATCH 3/3] virtiofsd: Check file type in lo_flush()

[Vivek Goyal]

On Thu, Dec 10, 2020 at 08:03:03PM +0000, Dr. David Alan Gilbert wrote:
> * Vivek Goyal (vgoyal@redhat.com) wrote:
> > Currently lo_flush() is written in such a way that it expects to receive
> > a FLUSH requests on a regular file (and not directories). For example,
> > we call lo_fi_fd() which searches lo->fd_map. If we open directories
> > using opendir(), we keep don't keep track of these in lo->fd_map instead
> > we keep them in lo->dir_map. So we expect lo_flush() to be called on
> > regular files only.
> > 
> > Even linux fuse client calls FLUSH only for regular files and not
> > directories. So put a check for filetype and return EBADF if
> > lo_flush() is called on a non-regular file.
> > 
> > Reported-by: Laszlo Ersek <lersek@redhat.com>
> > Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> > ---
> >  tools/virtiofsd/passthrough_ll.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/tools/virtiofsd/passthrough_ll.c 
> > b/tools/virtiofsd/passthrough_ll.c
> > index 8ba79f503a..48a109d3f6 100644
> > --- a/tools/virtiofsd/passthrough_ll.c
> > +++ b/tools/virtiofsd/passthrough_ll.c
> > @@ -1968,7 +1968,7 @@ static void lo_flush(fuse_req_t req, fuse_ino_t ino, 
> > struct fuse_file_info *fi)
> >      struct lo_data *lo = lo_data(req);
> >  
> >      inode = lo_inode(req, ino);
> > -    if (!inode) {
> > +    if (!inode || !S_ISREG(inode->filetype)) {
> >          fuse_reply_err(req, EBADF);
> 
> Does that need a lo_inode_put(lo, &inode) in the new case?

Good catch. Yes if inode is valid but file type is not regular, we need
to put inode reference.

Do you want me to post a new patch or you will like to take care of
it.

Vivek