acpi: validate hotplug selector on access

When bus is looked up on a pci write, we didn't
validate that the lookup succeeded.
Fuzzers thus can trigger QEMU crash by dereferencing the NULL
bus pointer.

Fixes: b32bd763a1 ("pci: introduce acpi-index property for PCI device")
Fixes: CVE-2021-4158
Cc: "Igor Mammedov" <imammedo@redhat.com>
Fixes: https://gitlab.com/qemu-project/qemu/-/issues/770
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Ani Sinha <ani@anisinha.ca>
This commit is contained in:
Michael S. Tsirkin 2021-12-21 09:45:44 -05:00
parent 7656d9ce09
commit 9bd6565cce

View file

@ -491,6 +491,9 @@ static void pci_write(void *opaque, hwaddr addr, uint64_t data,
}
bus = acpi_pcihp_find_hotplug_bus(s, s->hotplug_select);
if (!bus) {
break;
}
QTAILQ_FOREACH_SAFE(kid, &bus->qbus.children, sibling, next) {
Object *o = OBJECT(kid->child);
PCIDevice *dev = PCI_DEVICE(o);