ghsa-5xfg-8mp6-pr5f
Vulnerability from github
Published
2024-05-21 18:31
Modified
2024-05-21 18:31
Details

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

cxl/region: Fix null pointer dereference for resetting decoder

Not all decoders have a reset callback.

The CXL specification allows a host bridge with a single root port to have no explicit HDM decoders. Currently the region driver assumes there are none. As such the CXL core creates a special pass through decoder instance without a commit/reset callback.

Prior to this patch, the ->reset() callback was called unconditionally when calling cxl_region_decode_reset. Thus a configuration with 1 Host Bridge, 1 Root Port, and one directly attached CXL type 3 device or multiple CXL type 3 devices attached to downstream ports of a switch can cause a null pointer dereference.

Before the fix, a kernel crash was observed when we destroy the region, and a pass through decoder is reset.

The issue can be reproduced as below, 1) create a region with a CXL setup which includes a HB with a single root port under which a memdev is attached directly. 2) destroy the region with cxl destroy-region regionX -f.

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2022-48707"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-05-21T16:15:12Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/region: Fix null pointer dereference for resetting decoder\n\nNot all decoders have a reset callback.\n\nThe CXL specification allows a host bridge with a single root port to\nhave no explicit HDM decoders. Currently the region driver assumes there\nare none.  As such the CXL core creates a special pass through decoder\ninstance without a commit/reset callback.\n\nPrior to this patch, the -\u003ereset() callback was called unconditionally when\ncalling cxl_region_decode_reset. Thus a configuration with 1 Host Bridge,\n1 Root Port, and one directly attached CXL type 3 device or multiple CXL\ntype 3 devices attached to downstream ports of a switch can cause a null\npointer dereference.\n\nBefore the fix, a kernel crash was observed when we destroy the region, and\na pass through decoder is reset.\n\nThe issue can be reproduced as below,\n    1) create a region with a CXL setup which includes a HB with a\n    single root port under which a memdev is attached directly.\n    2) destroy the region with cxl destroy-region regionX -f.",
  "id": "GHSA-5xfg-8mp6-pr5f",
  "modified": "2024-05-21T18:31:17Z",
  "published": "2024-05-21T18:31:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-48707"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4fa4302d6dc7de7e8e74dc7405611a2efb4bf54b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a04c7d062b537ff787d00da95bdfe343260d4beb"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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