On Mon, Jan 10, 2022 at 04:40:08AM -0500, Michael S. Tsirkin wrote:
> On Thu, Jan 06, 2022 at 06:47:35AM +0000, Raphael Norwitz wrote:
> > When VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS support was added to
> > libvhost-user, no guardrails were added to protect against QEMU
> > attempting to hot-add too many RAM slots to a VM with a libvhost-user
> > based backed attached.
> >
> > This change adds the missing error handling by introducing a check on
> > the number of RAM slots the device has available before proceeding to
> > process the VHOST_USER_ADD_MEM_REG message.
> >
> > Suggested-by: Stefan Hajnoczi <[email protected]>
> > Signed-off-by: Raphael Norwitz <[email protected]>
> > ---
> > subprojects/libvhost-user/libvhost-user.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/subprojects/libvhost-user/libvhost-user.c
> > b/subprojects/libvhost-user/libvhost-user.c
> > index 77ddc96ddf..0fe3aa155b 100644
> > --- a/subprojects/libvhost-user/libvhost-user.c
> > +++ b/subprojects/libvhost-user/libvhost-user.c
> > @@ -690,6 +690,11 @@ vu_add_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
> > VuDevRegion *dev_region = &dev->regions[dev->nregions];
> > void *mmap_addr;
> >
> > + if (dev->nregions == VHOST_USER_MAX_RAM_SLOTS) {
> > + vu_panic(dev, "No free ram slots available");
>
> A bit more verbose maybe? Describe what happened to trigger this?
> e.g. adding a region with no free ram slots?
>
Ack
> > + return false;
> > + }
> > +
> > if (vmsg->fd_num != 1 ||
> > vmsg->size != sizeof(vmsg->payload.memreg)) {
> > vu_panic(dev, "VHOST_USER_REM_MEM_REG received multiple regions");
> > --
> > 2.20.1
>
