Re: [Qemu-devel] [PATCH v4 4/5] usb-mtp: Introduce write support for MTP objects

[Daniel P . Berrangé]

On Wed, Feb 21, 2018 at 12:11:00PM +0100, Gerd Hoffmann wrote:
> > > +static void usb_mtp_write_data(MTPState *s)
> > > +{
> > > +    MTPData *d = s->data_out;
> > > +    MTPObject *parent =
> > > +        usb_mtp_object_lookup(s, s->dataset.parent_handle);
> > > +    char *path = NULL;
> > > +    int rc = -1;
> > > +    mode_t mask = 0644;
> > > +
> > > +    assert(d != NULL);
> > > +
> > 
> > 
> > Somewhere in here should surely be validating the "readonly" flag.
> > 
> > > +    if (parent == NULL || !s->write_pending) {
> 
> Does happens here.  With a readonly device write_pending should
> never be true.

Unless I'm mis-understanding the flow, the next patch appears to set
write_pending = true, in response to a guest command, without checking
the readonly flag.

> 
> > > +        usb_mtp_queue_result(s, RES_INVALID_OBJECTINFO, d->trans,
> > > +                             0, 0, 0, 0);
> > > +        return;
> > > +    }
> 
> But adding an "assert(!readonly)" here as double-check surely doesn't hurt.
> 
> cheers,
>   Gerd
> 

Regards,
Daniel
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