CVE-2024-26812 vfio/pci: Create persistent INTx handler

2024-04-0508:24:42

Linux

www.cve.org

linux kernel

vulnerability

resolved

vfio/pci

intx handler

eventfd

deconfiguration

irq handler

set_irqs ioctl

unmask irqfd

igate mutex

irq_type configuration

eventfd_signal()

7.1 High

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

13.0%

JSON

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.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/vfio/pci/vfio_pci_intrs.c"
    ],
    "versions": [
      {
        "version": "89e1f7d4c66d",
        "lessThan": "b18fa894d615",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "89e1f7d4c66d",
        "lessThan": "27d40bf72dd9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "89e1f7d4c66d",
        "lessThan": "4cb0d7532126",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "89e1f7d4c66d",
        "lessThan": "7d29d4c72c1e",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "89e1f7d4c66d",
        "lessThan": "69276a555c74",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "89e1f7d4c66d",
        "lessThan": "4c089cefe309",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "89e1f7d4c66d",
        "lessThan": "0e09cf81959d",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "89e1f7d4c66d",
        "lessThan": "18c198c96a81",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/vfio/pci/vfio_pci_intrs.c"
    ],
    "versions": [
      {
        "version": "3.6",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "3.6",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.274",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.215",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.154",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.84",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.24",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.7.12",
        "lessThanOrEqual": "6.7.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.8.3",
        "lessThanOrEqual": "6.8.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.9",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]