ghsa-5xfg-8mp6-pr5f
Vulnerability from github
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.
{ "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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