From 529a5d908f5d16714b8ae0a51eaaaa84994dfae8 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Tue, 21 Dec 2021 09:45:44 -0500 Subject: [PATCH 1/2] acpi: validate hotplug selector on access MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Jon Maloy RH-MergeRequest: 97: acpi: validate hotplug selector on access RH-Commit: [1/1] 79bcfb0df0091e2b716d2e1c545f047b3409c26c (jmaloy/qemu-kvm) RH-Bugzilla: 2036580 RH-Acked-by: Miroslav Rezanina RH-Acked-by: Daniel P. Berrangé RH-Acked-by: Igor Mammedov 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" Fixes: https://gitlab.com/qemu-project/qemu/-/issues/770 Signed-off-by: Michael S. Tsirkin Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Ani Sinha (cherry picked from commit 9bd6565ccee68f72d5012e24646e12a1c662827e) Signed-off-by: Jon Maloy --- hw/acpi/pcihp.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c index 30405b5113..a5e182dd3a 100644 --- a/hw/acpi/pcihp.c +++ b/hw/acpi/pcihp.c @@ -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); -- 2.27.0