In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
virt: vmgenid: set driver_data before registering notification handlers<\/p>\n
Both probe paths register their notification handler before assigning
\ndriver_data, which the handler dereferences.<\/p>\n
In the devicetree path, the notification IRQ can fire as soon as
\ndevm_request_irq() registers the handler: the interrupt may already be
\npending at probe time, for example when a VMM injects the
\ngeneration-changed notification while restoring a guest from a snapshot
\nthat was taken before the driver had probed (Firecracker does exactly
\nthis on snapshot restore). The IRQ is also requested with IRQF_SHARED,
\nso another device sharing the line can trigger the handler just as
\nearly. The handler then calls vmgenid_notify(), which dereferences the
\nstill-NULL driver_data and panics:<\/p>\n
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
\n CPU: 0 UID: 0 PID: 1 Comm: swapper\/0 Not tainted 6.18.38+ #1 PREEMPT(none)
\n Hardware name: linux,dummy-virt (DT)
\n pc : vmgenid_notify.isra.0+0x24\/0x8c
\n lr : vmgenid_of_irq_handler+0x14\/0x34
\n Call trace:
\n vmgenid_notify.isra.0+0x24\/0x8c (P)
\n vmgenid_of_irq_handler+0x14\/0x34
\n __handle_irq_event_percpu+0x44\/0x1bc
\n handle_irq_event+0x4c\/0xb4
\n handle_fasteoi_irq+0xf8\/0x1f8<\/p>\n
The ACPI path has the same ordering problem: the handler is installed
\nwith acpi_install_notify_handler() before driver_data is assigned.
\nACPI notifications are dispatched asynchronously from a workqueue, so
\nthe window is narrow, but a notification arriving between the two calls
\nhits the same NULL dereference.<\/p>\n
Assign driver_data before registering the handlers. The state is fully
\ninitialized at that point, so the handlers are safe to run. Should
\nregistration fail, the probe error path leaves no dangling pointer
\nbehind: the driver core clears driver_data in device_unbind_cleanup().<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
virt: vmgenid: set driver_data before registering notification handlers<\/p>\n
Both probe paths register their notification handler befor<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-41313","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/41313","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=41313"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=41313"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=41313"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}