bpf: Make sure internal and UAPI bpf_redirect flags don't overlap

{
  "id": "f77b022fc8d08e3cccb91dfc1b613ddf1a7d1ba98ce40dfcafc8a933368de40b",
  "url": "https://osv.dev/vulnerability/CVE-2024-50163",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "bpf: Make sure internal and UAPI bpf_redirect flags don't overlap",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: bpf: Make sure internal and UAPI bpf_redirect flags don't overlap The bpf_redirect_info is shared between the SKB and XDP redirect paths, and the two paths use the same numeric flag values in the ri->flags field (specifically, BPF_F_BROADCAST == BPF_F_NEXTHOP). This means that if skb bpf_redirect_neigh() is used with a non-NULL params argument and, subsequently, an XDP redirect is performed using the same bpf_redirect_info struct, the XDP path will get confused and end up crashing, which syzbot managed to trigger. With the stack-allocated bpf_redirect_info, the structure is no longer shared between the SKB and XDP paths, so the crash doesn't happen anymore. However, different code paths using identically-numbered flag values in the same struct field still seems like a bit of a mess, so this patch cleans that up by moving the flag definitions together and redefining the three flags in BPF_F_REDIRECT_INTERNAL to not overlap with the flags used for XDP. It also adds a BUILD_BUG_ON() check to make sure the overlap is not re-introduced by mistake.",
    "evidence": "osv:CVE-2024-50163",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "5.15.170",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.115",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.59",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.11.6",
            "evidence": "/affected/1/ranges"
          }
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        "affected_versions": []
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    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2024-50163",
      "aliases": [
        "CVE-2024-50163"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
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              "type": "GIT",
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50163.json"
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      ],
      "modified": "2026-10-28T02:30:45.540752947Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/09d88791c7cd888d5195c84733caf9183dcfbd16",
        "https://git.kernel.org/stable/c/0fca5ed4be8e8bfbfb9bd97845af596bab7192d3",
        "https://git.kernel.org/stable/c/314dbee9fe4f5cee36435465de52c988d7caa466",
        "https://git.kernel.org/stable/c/4e1e428533845d48828bd3875c0e92e8565b9962",
        "https://git.kernel.org/stable/c/cec288e05ceac9a0d3a3a1fd279534b11844c826",
        "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50163.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-50163",
        "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/2024/50xxx/CVE-2024-50163.json"
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    "related_cves": [
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        "value": "CVE-2024-50163",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 513560,
  "published_at": "2024-11-07T09:31:40.146+00:00"
}