bpf: Skip invalid kfunc call in backtrack_insn

{
  "id": "f47bbbd44adf068e2edf93cfdce3d1065746f0023ad4a21ffc2f41cb6e0cc413",
  "url": "https://osv.dev/vulnerability/CVE-2023-52928",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "bpf: Skip invalid kfunc call in backtrack_insn",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: bpf: Skip invalid kfunc call in backtrack_insn The verifier skips invalid kfunc call in check_kfunc_call(), which would be captured in fixup_kfunc_call() if such insn is not eliminated by dead code elimination. However, this can lead to the following warning in backtrack_insn(), also see [1]: ------------[ cut here ]------------ verifier backtracking bug WARNING: CPU: 6 PID: 8646 at kernel/bpf/verifier.c:2756 backtrack_insn kernel/bpf/verifier.c:2756 __mark_chain_precision kernel/bpf/verifier.c:3065 mark_chain_precision kernel/bpf/verifier.c:3165 adjust_reg_min_max_vals kernel/bpf/verifier.c:10715 check_alu_op kernel/bpf/verifier.c:10928 do_check kernel/bpf/verifier.c:13821 [inline] do_check_common kernel/bpf/verifier.c:16289 [...] So make backtracking conservative with this by returning ENOTSUPP. [1] https://lore.kernel.org/bpf/CACkBjsaXNceR8ZjkLG=dT3P=4A8SBsg0Z5h5PWLryF5=ghKq=g@mail.gmail.com/",
    "evidence": "osv:CVE-2023-52928",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.93",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2023-52928",
      "aliases": [
        "CVE-2023-52928"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "e6ac2450d6dee3121cd8bbf2907b78a68a8a353d"
                },
                {
                  "fixed": "6e2fac197de2c4c041bdd8982cffb104689113f1"
                },
                {
                  "fixed": "74eec8266f37aff609db6a2f2b093e56a11c28c4"
                },
                {
                  "fixed": "d3178e8a434b58678d99257c0387810a24042fb6"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-52928.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.13.0"
                },
                {
                  "fixed": "5.15.93"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.11"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-52928.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:49.824214098Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/6e2fac197de2c4c041bdd8982cffb104689113f1",
        "https://git.kernel.org/stable/c/74eec8266f37aff609db6a2f2b093e56a11c28c4",
        "https://git.kernel.org/stable/c/d3178e8a434b58678d99257c0387810a24042fb6",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/52xxx/CVE-2023-52928.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-52928",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/52xxx/CVE-2023-52928.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-52928",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 518228,
  "published_at": "2025-03-27T16:37:10.471+00:00"
}