* Michael S. Tsirkin (m...@redhat.com) wrote: > On Fri, Jun 27, 2014 at 03:42:10PM +0100, Dr. David Alan Gilbert wrote: > > * Michael S. Tsirkin (m...@redhat.com) wrote: > > > On Fri, Jun 27, 2014 at 09:34:38AM +0100, Dr. David Alan Gilbert (git) > > > wrote: > > > > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > > > > > > > > Commit 'virtio: validate config_len on load' restricted config_len > > > > loaded from the wire to match the config_len that the device had. > > > > > > > > Unfortunately, there are cases where this isn't true, the one > > > > we found it on was the wqe addition in virtio-blk. > > > > > > I think you mean wce. > > > > Oops - yes. > > > > > > Allow mismatched config-lengths: > > > > *) If the version on the wire is shorter then ensure that the > > > > remainder is 0xff filled (as virtio_config_read does on > > > > out of range reads) > > > > *) If the version on the wire is longer, load what we have space > > > > for and skip the rest. > > > > > > > > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > > > > > > Looks good overall, but I am having thoughts about the > > > padding with 0xff. > > > We previously didn't do this (before virtio: validate config_len on > > > load) so it seems safest (at least for 2.1) not to do it now either. > > > > Who allocates that memory? If it's known to be a value then I agree; however > > if it's uninitialised then I think it's best to pick a value rather than > > have behaviour that depends on random junk in the memory. > > It's initialized: e.g. for net it includes the mac, > for block the wce value.
OK, I've just posted a v2 that is the simplified code you suggested. (Not had quite as much testing as my previous version yet). Dave -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
