ghsa-6985-fmpm-h392
Vulnerability from github
Published
2025-12-30 15:30
Modified
2025-12-30 15:30
Details

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

bpf: Fix issue in verifying allow_ptr_leaks

After we converted the capabilities of our networking-bpf program from cap_sys_admin to cap_net_admin+cap_bpf, our networking-bpf program failed to start. Because it failed the bpf verifier, and the error log is "R3 pointer comparison prohibited".

A simple reproducer as follows,

SEC("cls-ingress") int ingress(struct __sk_buff skb) { struct iphdr iph = (void *)(long)skb->data + sizeof(struct ethhdr);

if ((long)(iph + 1) > (long)skb->data_end)
    return TC_ACT_STOLEN;
return TC_ACT_OK;

}

Per discussion with Yonghong and Alexei [1], comparison of two packet pointers is not a pointer leak. This patch fixes it.

Our local kernel is 6.1.y and we expect this fix to be backported to 6.1.y, so stable is CCed.

[1]. https://lore.kernel.org/bpf/CAADnVQ+Nmspr7Si+pxWn8zkE7hX-7s93ugwC+94aXSy4uQ9vBg@mail.gmail.com/

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2023-54181"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-30T13:16:06Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix issue in verifying allow_ptr_leaks\n\nAfter we converted the capabilities of our networking-bpf program from\ncap_sys_admin to cap_net_admin+cap_bpf, our networking-bpf program\nfailed to start. Because it failed the bpf verifier, and the error log\nis \"R3 pointer comparison prohibited\".\n\nA simple reproducer as follows,\n\nSEC(\"cls-ingress\")\nint ingress(struct __sk_buff *skb)\n{\n\tstruct iphdr *iph = (void *)(long)skb-\u003edata + sizeof(struct ethhdr);\n\n\tif ((long)(iph + 1) \u003e (long)skb-\u003edata_end)\n\t\treturn TC_ACT_STOLEN;\n\treturn TC_ACT_OK;\n}\n\nPer discussion with Yonghong and Alexei [1], comparison of two packet\npointers is not a pointer leak. This patch fixes it.\n\nOur local kernel is 6.1.y and we expect this fix to be backported to\n6.1.y, so stable is CCed.\n\n[1]. https://lore.kernel.org/bpf/CAADnVQ+Nmspr7Si+pxWn8zkE7hX-7s93ugwC+94aXSy4uQ9vBg@mail.gmail.com/",
  "id": "GHSA-6985-fmpm-h392",
  "modified": "2025-12-30T15:30:30Z",
  "published": "2025-12-30T15:30:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-54181"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5927f0172d2809d8fc09c1ba667280b0387e9f73"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/acfdc8b77016c8e648aadc283177546c88083dd3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c96c67991aac6401b4c6996093bccb704bb2ea4b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d75e30dddf73449bc2d10bb8e2f1a2c446bc67a2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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