CVE-2024-49998: Software Security Vulnerability Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3xm8-389p-x4rm",
  "modified" : "2026-10-15T03:34:12Z",
  "published" : "2024-10-21T18:30:59Z",
  "aliases" : [ "CVE-2024-49998" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: dsa: improve shutdown sequence\n\nAlexander Sverdlin presents 2 problems during shutdown with the\nlan9303 driver. One is specific to lan9303 and the other just happens\nto reproduce there.\n\nThe first problem is that lan9303 is unique among DSA drivers in that it\ncalls dev_get_drvdata() at \"arbitrary runtime\" (not probe, not shutdown,\nnot remove):\n\nphy_state_machine()\n-> ...\n   -> dsa_user_phy_read()\n      -> ds->ops->phy_read()\n         -> lan9303_phy_read()\n            -> chip->ops->phy_read()\n               -> lan9303_mdio_phy_read()\n                  -> dev_get_drvdata()\n\nBut we never stop the phy_state_machine(), so it may continue to run\nafter dsa_switch_shutdown(). Our common pattern in all DSA drivers is\nto set drvdata to NULL to suppress the remove() method that may come\nafterwards. But in this case it will result in an NPD.\n\nThe second problem is that the way in which we set\ndp->conduit->dsa_ptr = NULL; is concurrent with receive packet\nprocessing. dsa_switch_rcv() checks once whether dev->dsa_ptr is NULL,\nbut afterwards, rather than continuing to use that non-NULL value,\ndev->dsa_ptr is dereferenced again and again without NULL checks:\ndsa_conduit_find_user() and many other places. In between dereferences,\nthere is no locking to ensure that what was valid once continues to be\nvalid.\n\nBoth problems have the common aspect that closing the conduit interface\nsolves them.\n\nIn the first case, dev_close(conduit) triggers the NETDEV_GOING_DOWN\nevent in dsa_user_netdevice_event() which closes user ports as well.\ndsa_port_disable_rt() calls phylink_stop(), which synchronously stops\nthe phylink state machine, and ds->ops->phy_read() will thus no longer\ncall into the driver after this point.\n\nIn the second case, dev_close(conduit) should do this, as per\nDocumentation/networking/driver.rst:\n\n| Quiescence\n| ----------\n|\n| After the ndo_stop routine has been called, the hardware must\n| not receive or transmit any data.  All in flight packets must\n| be aborted. If necessary, poll or wait for completion of\n| any reset commands.\n\nSo it should be sufficient to ensure that later, when we zeroize\nconduit->dsa_ptr, there will be no concurrent dsa_switch_rcv() call\non this conduit.\n\nThe addition of the netif_device_detach() function is to ensure that\nioctls, rtnetlinks and ethtool requests on the user ports no longer\npropagate down to the driver - we're no longer prepared to handle them.\n\nThe race condition actually did not exist when commit 0650bf52b31f\n(\"net: dsa: be compatible with masters which unregister on shutdown\")\nfirst introduced dsa_switch_shutdown(). It was created later, when we\nstopped unregistering the user interfaces from a bad spot, and we just\nreplaced that sequence with a racy zeroization of conduit->dsa_ptr\n(one which doesn't ensure that the interfaces aren't up).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2024-49998"
  }, {
    "type" : "WEB",
    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
  }, {
    "type" : "WEB",
    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
  }, {
    "type" : "WEB",
    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-457936.html"
  }, {
    "type" : "WEB",
    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-784472.html"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/2e93bf719462ac6d23c881c8b93e5dc9bf5ab7f5"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/6c24a03a61a245fe34d47582898331fa034b6ccd"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/87bd909a7014e32790e8c759d5b7694a95778ca5"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/ab5d3420a1120950703dbdc33698b28a6ebc3d23"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/ab9e90619b6339becc5415647ae154a9a46a044d"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/b4a65d479213fe84ecb14e328271251eebe69492"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-367" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2024-10-21T18:15:19Z"
  }
}