Re: [PATCH 051/104] virtiofsd: Parse flag FUSE_WRITE_KILL_PRIV

[Dr. David Alan Gilbert]

* Misono Tomohiro (address@hidden) wrote:
> > From: Vivek Goyal <address@hidden>
> > 
> > Caller can set FUSE_WRITE_KILL_PRIV in write_flags. Parse it and pass it
> > to the filesystem.
> > 
> > Signed-off-by: Vivek Goyal <address@hidden>
> > ---
> >  tools/virtiofsd/fuse_common.h   | 6 +++++-
> >  tools/virtiofsd/fuse_lowlevel.c | 4 +++-
> >  2 files changed, 8 insertions(+), 2 deletions(-)
> > 
> > diff --git a/tools/virtiofsd/fuse_common.h b/tools/virtiofsd/fuse_common.h
> > index 147c043bd9..1e8191b7a6 100644
> > --- a/tools/virtiofsd/fuse_common.h
> > +++ b/tools/virtiofsd/fuse_common.h
> > @@ -93,8 +93,12 @@ struct fuse_file_info {
> >       */
> >      unsigned int cache_readdir:1;
> >  
> > +    /* Indicates that suid/sgid bits should be removed upon write */
> > +    unsigned int kill_priv:1;
> > +
> > +
> >      /** Padding.  Reserved for future use*/
> > -    unsigned int padding:25;
> > +    unsigned int padding:24;
> >      unsigned int padding2:32;
> >  
> >      /*
> > diff --git a/tools/virtiofsd/fuse_lowlevel.c 
> > b/tools/virtiofsd/fuse_lowlevel.c
> > index bd5ca2f157..c8a3b1597a 100644
> > --- a/tools/virtiofsd/fuse_lowlevel.c
> > +++ b/tools/virtiofsd/fuse_lowlevel.c
> > @@ -1144,6 +1144,7 @@ static void do_write(fuse_req_t req, fuse_ino_t 
> > nodeid,
> >      memset(&fi, 0, sizeof(fi));
> >      fi.fh = arg->fh;
> >      fi.writepage = (arg->write_flags & FUSE_WRITE_CACHE) != 0;
> > +    fi.kill_priv = !!(arg->write_flags & FUSE_WRITE_KILL_PRIV);
> >  
> >      fi.lock_owner = arg->lock_owner;
> >      fi.flags = arg->flags;
> > @@ -1179,7 +1180,8 @@ static void do_write_buf(fuse_req_t req, fuse_ino_t 
> > nodeid,
> >      fi.lock_owner = arg->lock_owner;
> >      fi.flags = arg->flags;
> >      fi.fh = arg->fh;
> > -    fi.writepage = arg->write_flags & FUSE_WRITE_CACHE;
> > +    fi.writepage = !!(arg->write_flags & FUSE_WRITE_CACHE);
> > +    fi.kill_priv = !!(arg->write_flags & FUSE_WRITE_KILL_PRIV);
> >  
> >      if (ibufv->count == 1) {
> >          assert(!(tmpbufv.buf[0].flags & FUSE_BUF_IS_FD));
> > -- 
> > 2.23.0
> 
> Reviewed-by: Misono Tomohiro <address@hidden>

Thank you.

> side-note: virtiofs uses write_buf() and therefore do_write() is never called.
> How about cleanup the function?

Yes I think you're right; I need to go through and check there's no
corner case which can get into the plain do_write.

Dave

> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK