Re: [Qemu-devel] [PATCH] 9pfs: fix memory leak in v9fs_xattrcreate

[Greg Kurz]

On Mon, 10 Oct 2016 19:54:01 +0800
Li Qiang <address@hidden> wrote:

> I think the 'xattr_fidp->fs.xattr.name' will not leak as the
> 'v9fs_string_copy' will first free the fs.xattr.name.
> 

Indeed!

> Thanks.
> 

Cheers.

--
Greg

> 2016-10-10 19:28 GMT+08:00 Greg Kurz <address@hidden>:
> 
> > On Mon, 10 Oct 2016 13:20:51 +0200
> > Greg Kurz <address@hidden> wrote:
> >
> > > On Mon, 10 Oct 2016 03:41:38 -0700
> > > Li Qiang <address@hidden> wrote:
> > >
> > > > From: Li Qiang <address@hidden>
> > > >
> > > > The 'fs.xattr.value' field in V9fsFidState object doesn't consider the
> > > > situation that this field has been allocated previously. Every time, it
> > > > will be allocated directly. This leads a host memory leak issue. This
> > > > patch fix this.
> > > >
> > > > Signed-off-by: Li Qiang <address@hidden>
> > > > ---
> > >
> > > I'll add to the changelog that this may happen if the client sends a
> > > Txattrcreate message with the same fid number before the fid was
> > > clunked.
> > >
> > > Reviewed-by: Greg Kurz <address@hidden>
> > >
> >
> > Oops I may have answered to fast... what about xattr_fidp->fs.xattr.name ?
> > It looks like it is leaked the same way...
> >
> > > >  hw/9pfs/9p.c | 1 +
> > > >  1 file changed, 1 insertion(+)
> > > >
> > > > diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> > > > index 8751c19..e4040dc 100644
> > > > --- a/hw/9pfs/9p.c
> > > > +++ b/hw/9pfs/9p.c
> > > > @@ -3282,6 +3282,7 @@ static void v9fs_xattrcreate(void *opaque)
> > > >      xattr_fidp->fs.xattr.flags = flags;
> > > >      v9fs_string_init(&xattr_fidp->fs.xattr.name);
> > > >      v9fs_string_copy(&xattr_fidp->fs.xattr.name, &name);
> > > > +    g_free(xattr_fidp->fs.xattr.value);
> > > >      xattr_fidp->fs.xattr.value = g_malloc0(size);
> > > >      err = offset;
> > > >      put_fid(pdu, file_fidp);
> > >
> >
> >