Resource Injection Affecting kernel-core package, versions *


Severity

Recommended
low

Based on Red Hat Enterprise Linux security rating

    Threat Intelligence

    EPSS
    0.05% (17th percentile)

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  • Snyk ID SNYK-RHEL9-KERNELCORE-7469953
  • published 17 Jul 2024
  • disclosed 16 Jul 2024

How to fix?

There is no fixed version for RHEL:9 kernel-core.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-core package and not the kernel-core package as distributed by RHEL. See How to fix? for RHEL:9 relevant fixed versions and status.

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

net: dsa: seville: register the mdiobus under devres

As explained in commits: 74b6d7d13307 ("net: dsa: realtek: register the MDIO bus under devres") 5135e96a3dd2 ("net: dsa: don't allocate the slave_mii_bus using devres")

mdiobus_free() will panic when called from devm_mdiobus_free() <- devres_release_all() <- __device_release_driver(), and that mdiobus was not previously unregistered.

The Seville VSC9959 switch is a platform device, so the initial set of constraints that I thought would cause this (I2C or SPI buses which call ->remove on ->shutdown) do not apply. But there is one more which applies here.

If the DSA master itself is on a bus that calls ->remove from ->shutdown (like dpaa2-eth, which is on the fsl-mc bus), there is a device link between the switch and the DSA master, and device_links_unbind_consumers() will unbind the seville switch driver on shutdown.

So the same treatment must be applied to all DSA switch drivers, which is: either use devres for both the mdiobus allocation and registration, or don't use devres at all.

The seville driver has a code structure that could accommodate both the mdiobus_unregister and mdiobus_free calls, but it has an external dependency upon mscc_miim_setup() from mdio-mscc-miim.c, which calls devm_mdiobus_alloc_size() on its behalf. So rather than restructuring that, and exporting yet one more symbol mscc_miim_teardown(), let's work with devres and replace of_mdiobus_register with the devres variant. When we use all-devres, we can ensure that devres doesn't free a still-registered bus (it either runs both callbacks, or none).

CVSS Scores

version 3.1
Expand this section

Red Hat

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

SUSE

4.4 medium