Improper Locking Affecting kernel-rt-debug package, versions *


Severity

Recommended
0.0
medium
0
10

Based on CentOS security rating

    Threat Intelligence

    EPSS
    0.04% (6th percentile)

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  • Snyk ID SNYK-CENTOS7-KERNELRTDEBUG-8046907
  • published 18 Sep 2024
  • disclosed 18 Sep 2024

How to fix?

There is no fixed version for Centos:7 kernel-rt-debug.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug package and not the kernel-rt-debug package as distributed by Centos. See How to fix? for Centos:7 relevant fixed versions and status.

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

PCI: Add missing bridge lock to pci_bus_lock()

One of the true positives that the cfg_access_lock lockdep effort identified is this sequence:

WARNING: CPU: 14 PID: 1 at drivers/pci/pci.c:4886 pci_bridge_secondary_bus_reset+0x5d/0x70 RIP: 0010:pci_bridge_secondary_bus_reset+0x5d/0x70 Call Trace: <TASK> ? __warn+0x8c/0x190 ? pci_bridge_secondary_bus_reset+0x5d/0x70 ? report_bug+0x1f8/0x200 ? handle_bug+0x3c/0x70 ? exc_invalid_op+0x18/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? pci_bridge_secondary_bus_reset+0x5d/0x70 pci_reset_bus+0x1d8/0x270 vmd_probe+0x778/0xa10 pci_device_probe+0x95/0x120

Where pci_reset_bus() users are triggering unlocked secondary bus resets. Ironically pci_bus_reset(), several calls down from pci_reset_bus(), uses pci_bus_lock() before issuing the reset which locks everything but the bridge itself.

For the same motivation as adding:

bridge = pci_upstream_bridge(dev); if (bridge) pci_dev_lock(bridge);

to pci_reset_function() for the "bus" and "cxl_bus" reset cases, add pci_dev_lock() for @bus->self to pci_bus_lock().

[bhelgaas: squash in recursive locking deadlock fix from Keith Busch: https://lore.kernel.org/r/20240711193650.701834-1-kbusch@meta.com]

CVSS Scores

version 3.1
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NVD

5.5 medium
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    Low
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    None
  • Integrity (I)
    None
  • Availability (A)
    High
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Red Hat

5.5 medium
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SUSE

4.7 medium