ghsa-hc84-56cx-wr29
Vulnerability from github
Published
2025-03-12 12:30
Modified
2025-03-13 18:32
Severity ?
3.3 (Low) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Details

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

bpf: Fix softlockup in arena_map_free on 64k page kernel

On an aarch64 kernel with CONFIG_PAGE_SIZE_64KB=y, arena_htab tests cause a segmentation fault and soft lockup. The same failure is not observed with 4k pages on aarch64.

It turns out arena_map_free() is calling apply_to_existing_page_range() with the address returned by bpf_arena_get_kern_vm_start(). If this address is not page-aligned the code ends up calling apply_to_pte_range() with that unaligned address causing soft lockup.

Fix it by round up GUARD_SZ to PAGE_SIZE << 1 so that the division by 2 in bpf_arena_get_kern_vm_start() returns a page-aligned value.

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{
  "affected": [],
  "aliases": [
    "CVE-2025-21851"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-667"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-03-12T10:15:17Z",
    "severity": "LOW"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix softlockup in arena_map_free on 64k page kernel\n\nOn an aarch64 kernel with CONFIG_PAGE_SIZE_64KB=y,\narena_htab tests cause a segmentation fault and soft lockup.\nThe same failure is not observed with 4k pages on aarch64.\n\nIt turns out arena_map_free() is calling\napply_to_existing_page_range() with the address returned by\nbpf_arena_get_kern_vm_start().  If this address is not page-aligned\nthe code ends up calling apply_to_pte_range() with that unaligned\naddress causing soft lockup.\n\nFix it by round up GUARD_SZ to PAGE_SIZE \u003c\u003c 1 so that the\ndivision by 2 in bpf_arena_get_kern_vm_start() returns\na page-aligned value.",
  "id": "GHSA-hc84-56cx-wr29",
  "modified": "2025-03-13T18:32:21Z",
  "published": "2025-03-12T12:30:58Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21851"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/517e8a7835e8cfb398a0aeb0133de50e31cae32b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/787d556a3de447e70964a4bdeba9196f62a62b1e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c1f3f3892d4526f18aaeffdb6068ce861e793ee3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ]
}


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