f2fs: fix to do sanity check on sit_bitmap_size

{
  "id": "cada8a172618e2867f244b9512a6554ff912eaabc740fd8df7b9f2e4914d8cdf",
  "url": "https://osv.dev/vulnerability/CVE-2025-38218",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "f2fs: fix to do sanity check on sit_bitmap_size",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to do sanity check on sit_bitmap_size w/ below testcase, resize will generate a corrupted image which contains inconsistent metadata, so when mounting such image, it will trigger kernel panic: touch img truncate -s $((512*1024*1024*1024)) img mkfs.f2fs -f img $((256*1024*1024)) resize.f2fs -s -i img -t $((1024*1024*1024)) mount img /mnt/f2fs ------------[ cut here ]------------ kernel BUG at fs/f2fs/segment.h:863! Oops: invalid opcode: 0000 [#1] SMP PTI CPU: 11 UID: 0 PID: 3922 Comm: mount Not tainted 6.15.0-rc1+ #191 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:f2fs_ra_meta_pages+0x47c/0x490 Call Trace: f2fs_build_segment_manager+0x11c3/0x2600 f2fs_fill_super+0xe97/0x2840 mount_bdev+0xf4/0x140 legacy_get_tree+0x2b/0x50 vfs_get_tree+0x29/0xd0 path_mount+0x487/0xaf0 __x64_sys_mount+0x116/0x150 do_syscall_64+0x82/0x190 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fdbfde1bcfe The reaseon is: sit_i->bitmap_size is 192, so size of sit bitmap is 192*8=1536, at maximum there are 1536 sit blocks, however MAIN_SEGS is 261893, so that sit_blk_cnt is 4762, build_sit_entries() -> current_sit_addr() tries to access out-of-boundary in sit_bitmap at offset from [1536, 4762), once sit_bitmap and sit_bitmap_mirror is not the same, it will trigger f2fs_bug_on(). Let's add sanity check in f2fs_sanity_check_ckpt() to avoid panic.",
    "evidence": "osv:CVE-2025-38218",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.239",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.186",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.142",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.95",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.35",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.15.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-38218",
      "aliases": [
        "CVE-2025-38218"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "82f51bff393e4c12cf4de553120ca831cfa4ef19"
                },
                {
                  "fixed": "38ef48a8afef8df646b6f6ae7abb872f18b533c1"
                },
                {
                  "fixed": "ad862f71016ba38039df1c96ed55c0a4314cc183"
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                {
                  "fixed": "79ef8a6c4ec53d327580fd7d2b522cf4f1d05b0c"
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                {
                  "fixed": "ee1b421c469876544e297ec1090574bd76100247"
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                  "fixed": "3e5ac62a56a24f4d88ce8ffd7bc452428b235868"
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                {
                  "fixed": "5db0d252c64e91ba1929c70112352e85dc5751e7"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38218.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "3.8.0"
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                  "fixed": "6.6.95"
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              ]
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.7.0"
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                  "fixed": "6.12.35"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.13.0"
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38218.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:31.688540931Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/38ef48a8afef8df646b6f6ae7abb872f18b533c1",
        "https://git.kernel.org/stable/c/3e5ac62a56a24f4d88ce8ffd7bc452428b235868",
        "https://git.kernel.org/stable/c/5db0d252c64e91ba1929c70112352e85dc5751e7",
        "https://git.kernel.org/stable/c/79ef8a6c4ec53d327580fd7d2b522cf4f1d05b0c",
        "https://git.kernel.org/stable/c/82f51bff393e4c12cf4de553120ca831cfa4ef19",
        "https://git.kernel.org/stable/c/ad862f71016ba38039df1c96ed55c0a4314cc183",
        "https://git.kernel.org/stable/c/ee1b421c469876544e297ec1090574bd76100247",
        "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html",
        "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38218.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-38218",
        "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/2025/38xxx/CVE-2025-38218.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-38218",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 498354,
  "published_at": "2025-07-04T13:37:35.157+00:00"
}