Description

In the Linux kernel, the following vulnerability has been resolved:

vfio/pci: Create persistent INTx handler

A vulnerability exists where the eventfd for INTx signaling can be
deconfigured, which unregisters the IRQ handler but still allows
eventfds to be signaled with a NULL context through the SET_IRQS ioctl
or through unmask irqfd if the device interrupt is pending.

Ideally this could be solved with some additional locking; the igate
mutex serializes the ioctl and config space accesses, and the interrupt
handler is unregistered relative to the trigger, but the irqfd path
runs asynchronous to those. The igate mutex cannot be acquired from the
atomic context of the eventfd wake function. Disabling the irqfd
relative to the eventfd registration is potentially incompatible with
existing userspace.

As a result, the solution implemented here moves configuration of the
INTx interrupt handler to track the lifetime of the INTx context object
and irq_type configuration, rather than registration of a particular
trigger eventfd. Synchronization is added between the ioctl path and
eventfd_signal() wrapper such that the eventfd trigger can be
dynamically updated relative to in-flight interrupts or irqfd callbacks.

Classification

CVE ID: CVE-2024-26812

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 15.26% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/b18fa894d615c8527e15d96b76c7448800e13899
https://git.kernel.org/stable/c/27d40bf72dd9a6600b76ad05859176ea9a1b4897
https://git.kernel.org/stable/c/4cb0d7532126d23145329826c38054b4e9a05e7c
https://git.kernel.org/stable/c/7d29d4c72c1e196cce6969c98072a272d1a703b3
https://git.kernel.org/stable/c/69276a555c740acfbff13fb5769ee9c92e1c828e
https://git.kernel.org/stable/c/4c089cefe30924fbe20dd1ee92774ea1f5eca834
https://git.kernel.org/stable/c/0e09cf81959d9f12b75ad5c6dd53d237432ed034
https://git.kernel.org/stable/c/18c198c96a815c962adc2b9b77909eec0be7df4d

Timeline