ghsa-px8r-2q8w-48v9
Vulnerability from github
Published
2024-07-16 12:30
Modified
2024-07-16 12:30
Details

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).

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{
   affected: [],
   aliases: [
      "CVE-2022-48814",
   ],
   database_specific: {
      cwe_ids: [],
      github_reviewed: false,
      github_reviewed_at: null,
      nvd_published_at: "2024-07-16T12:15:05Z",
      severity: null,
   },
   details: "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: dsa: seville: register the mdiobus under devres\n\nAs explained in commits:\n74b6d7d13307 (\"net: dsa: realtek: register the MDIO bus under devres\")\n5135e96a3dd2 (\"net: dsa: don't allocate the slave_mii_bus using devres\")\n\nmdiobus_free() will panic when called from devm_mdiobus_free() <-\ndevres_release_all() <- __device_release_driver(), and that mdiobus was\nnot previously unregistered.\n\nThe Seville VSC9959 switch is a platform device, so the initial set of\nconstraints that I thought would cause this (I2C or SPI buses which call\n->remove on ->shutdown) do not apply. But there is one more which\napplies here.\n\nIf the DSA master itself is on a bus that calls ->remove from ->shutdown\n(like dpaa2-eth, which is on the fsl-mc bus), there is a device link\nbetween the switch and the DSA master, and device_links_unbind_consumers()\nwill unbind the seville switch driver on shutdown.\n\nSo the same treatment must be applied to all DSA switch drivers, which\nis: either use devres for both the mdiobus allocation and registration,\nor don't use devres at all.\n\nThe seville driver has a code structure that could accommodate both the\nmdiobus_unregister and mdiobus_free calls, but it has an external\ndependency upon mscc_miim_setup() from mdio-mscc-miim.c, which calls\ndevm_mdiobus_alloc_size() on its behalf. So rather than restructuring\nthat, and exporting yet one more symbol mscc_miim_teardown(), let's work\nwith devres and replace of_mdiobus_register with the devres variant.\nWhen we use all-devres, we can ensure that devres doesn't free a\nstill-registered bus (it either runs both callbacks, or none).",
   id: "GHSA-px8r-2q8w-48v9",
   modified: "2024-07-16T12:30:40Z",
   published: "2024-07-16T12:30:40Z",
   references: [
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2022-48814",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/0e816362d823cd46c666e64d8bffe329ee22f4cc",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/1d13e7221035947c62800c9d3d99b4ed570e27e7",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/bd488afc3b39e045ba71aab472233f2a78726e7b",
      },
   ],
   schema_version: "1.4.0",
   severity: [],
}


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