Re: [PATCH] 9pfs: local: Do not follow symlink in _nofollow

[Greg Kurz <groug@kaod.org>]

On Wed, 27 Apr 2022 10:46:31 +0200
Christian Schoenebeck <qemu_oss@crudebyte.com> wrote:

> On Mittwoch, 27. April 2022 04:45:45 CEST Akihiko Odaki wrote:
> > Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com>
> > ---
> >  hw/9pfs/9p-local.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
> > index d42ce6d8b82..def8afdb4d6 100644
> > --- a/hw/9pfs/9p-local.c
> > +++ b/hw/9pfs/9p-local.c
> > @@ -365,7 +365,7 @@ static int fchmodat_nofollow(int dirfd, const char
> > *name, mode_t mode) if (fd == -1) {
> >          /* In case the file is writable-only and isn't a directory. */
> >          if (errno == EACCES) {
> > -            fd = openat_file(dirfd, name, O_WRONLY, 0);
> > +            fd = openat_file(dirfd, name, O_WRONLY | O_NOFOLLOW, 0);
> 
> O_NOFOLLOW flag is always added inside openat_file() implementation:
> 
> https://github.com/qemu/qemu/blob/master/hw/9pfs/9p-util.h#L60
> 
> So this change is not necessary AFAICS.
> 

Right, and with macOS in mind, maybe fchmodat(AT_SYMLINK_NOFOLLOW) just
works unlike with linux ?

> >          }
> >          if (fd == -1 && errno == EISDIR) {
> >              errno = EACCES;
> 
>