CVE-2024-45817
x86: Deadlock in vlapic_error()
In short
A flaw in Xen's x86 APIC error handling allows misconfigured error interrupts to cause the system to deadlock when an error interrupt recursively triggers another error, freezing the virtual processor.
Technical detail
An illegal vector configuration in the APIC error interrupt causes recursive calls to vlapic_error() that attempt to acquire the same lock multiple times, leading to deadlock. The attack vector requires guest-level configuration of the error interrupt vector; the recursion is bounded but the lock is not reentrant, causing system hang.
Summary generated and translated by AI from the official description.
In x86's APIC (Advanced Programmable Interrupt Controller) architecture,
error conditions are reported in a status register. Furthermore, the OS
can opt to receive an interrupt when a new error occurs.
It is possible to configure the error interrupt with an illegal vector,
which generates an error when an error interrupt is raised.
This case causes Xen to recurse through vlapic_error(). The recursion
itself is bounded; errors accumulate in the the status register and only
generate an interrupt when a new status bit becomes set.
However, the lock protecting this state in Xen will try to be taken
recursively, and deadlock.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Affected products
Xen · XenWant to know if your infrastructure is exposed to this?
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