bpftool: Fix undefined behavior in qsort(NULL, 0, ...)

{
  "id": "1699d5d78b73578338bd299d6439def0d4f0dd2b6114ad878990270602a8e262",
  "url": "https://osv.dev/vulnerability/CVE-2024-49987",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "bpftool: Fix undefined behavior in qsort(NULL, 0, ...)",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: bpftool: Fix undefined behavior in qsort(NULL, 0, ...) When netfilter has no entry to display, qsort is called with qsort(NULL, 0, ...). This results in undefined behavior, as UBSan reports: net.c:827:2: runtime error: null pointer passed as argument 1, which is declared to never be null Although the C standard does not explicitly state whether calling qsort with a NULL pointer when the size is 0 constitutes undefined behavior, Section 7.1.4 of the C standard (Use of library functions) mentions: \"Each of the following statements applies unless explicitly stated otherwise in the detailed descriptions that follow: If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer, or a pointer to non-modifiable storage when the corresponding parameter is not const-qualified) or a type (after promotion) not expected by a function with variable number of arguments, the behavior is undefined.\" To avoid this, add an early return when nf_link_info is NULL to prevent calling qsort with a NULL pointer.",
    "evidence": "osv:CVE-2024-49987",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.55",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.10.14",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.11.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2024-49987",
      "aliases": [
        "CVE-2024-49987"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "c2d9f9a7837ab29ccae0c42252f17d436bf0a501"
                },
                {
                  "fixed": "2e0f6f33f2aa87493b365a38a8fd87b8854b7734"
                },
                {
                  "fixed": "c208b02827eb642758cef65641995fd3f38c89af"
                },
                {
                  "fixed": "f04e2ad394e2755d0bb2d858ecb5598718bf00d5"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-49987.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.4.0"
                },
                {
                  "fixed": "6.6.55"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.10.14"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.11.0"
                },
                {
                  "fixed": "6.11.3"
                }
              ]
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-49987.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.344841120Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2e0f6f33f2aa87493b365a38a8fd87b8854b7734",
        "https://git.kernel.org/stable/c/c208b02827eb642758cef65641995fd3f38c89af",
        "https://git.kernel.org/stable/c/c2d9f9a7837ab29ccae0c42252f17d436bf0a501",
        "https://git.kernel.org/stable/c/f04e2ad394e2755d0bb2d858ecb5598718bf00d5",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/49xxx/CVE-2024-49987.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-49987",
        "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/2024/49xxx/CVE-2024-49987.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-49987",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 521038,
  "published_at": "2024-10-21T18:02:31.209+00:00"
}