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FKIE_CVE-2026-89490

Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-09-14 13:19
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix readdir position truncation on 32-bit kernels In ocfs2_dir_foreach_blk_el(), the directory cookie position is rebuilt with ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1)) | offset; `ctx->pos` is loff_t (signed 64-bit), while `sb->s_blocksize` is unsigned long. On 32-bit kernels unsigned long is 32-bit, so the mask ~(sb->s_blocksize - 1) is computed as a 32-bit unsigned value (e.g. 0xfffff000 for a 4 KiB block size). In the AND expression with the 64-bit `ctx->pos`, that unsigned operand is zero-extended to 64 bits per the usual arithmetic conversions, yielding 0x00000000fffff000. The high 32 bits of `ctx->pos` are silently cleared, even though directory size is allowed to exceed 4 GiB. When readdir() crosses the 4 GiB boundary on a 32-bit kernel the position is reset back into the first 4 GiB block, making the re-validation path re-enumerate already-returned dirents indefinitely. This is ocfs2_dir_foreach_blk_el(), the extent-list readdir path taken for all non-inline directories, so a directory large enough to cross 4 GiB reaches it. This is the same class of bug that commit 3dce5bb82c97 ("exfat: Fix bitwise operation having different size") fixed in exfat, and the fix mirrors the equivalent ext4 fix in this series. Cast the operand to loff_t so the mask is 64-bit before the AND: ctx->pos = (ctx->pos & ~((loff_t)sb->s_blocksize - 1)) | offset; 64-bit kernels are unaffected.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1001fb3b69a11eaa0dc7c7428f6edfa48b88997a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1ae7029823ae4c91664cb32eec7fb8dd5e1a337a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/94569154ba49f5f85645d2019c8e206213d8404e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a63308ab426f3a3c7e33b02c150ea59054620261
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b53e2b271eeb6040c2a4a78230c570dc41cdcfa4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c0c165487a2ea5a37ddcdab4259157b7a527129c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c28dc3407937aa8f225942538cd585c9b28ea65a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f9dd5cad8d09110ddff2db1fe756aae93c7552ff
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ocfs2/dir.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c28dc3407937aa8f225942538cd585c9b28ea65a",
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "versionType": "git"
            },
            {
              "lessThan": "94569154ba49f5f85645d2019c8e206213d8404e",
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "versionType": "git"
            },
            {
              "lessThan": "1ae7029823ae4c91664cb32eec7fb8dd5e1a337a",
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "versionType": "git"
            },
            {
              "lessThan": "f9dd5cad8d09110ddff2db1fe756aae93c7552ff",
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "versionType": "git"
            },
            {
              "lessThan": "1001fb3b69a11eaa0dc7c7428f6edfa48b88997a",
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "versionType": "git"
            },
            {
              "lessThan": "c0c165487a2ea5a37ddcdab4259157b7a527129c",
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "versionType": "git"
            },
            {
              "lessThan": "b53e2b271eeb6040c2a4a78230c570dc41cdcfa4",
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "versionType": "git"
            },
            {
              "lessThan": "a63308ab426f3a3c7e33b02c150ea59054620261",
              "status": "affected",
              "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ocfs2/dir.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.16"
            },
            {
              "lessThan": "2.6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: fix readdir position truncation on 32-bit kernels\n\nIn ocfs2_dir_foreach_blk_el(), the directory cookie position is\nrebuilt with\n\n\tctx-\u003epos = (ctx-\u003epos \u0026 ~(sb-\u003es_blocksize - 1)) | offset;\n\n`ctx-\u003epos` is loff_t (signed 64-bit), while `sb-\u003es_blocksize` is\nunsigned long.  On 32-bit kernels unsigned long is 32-bit, so the mask\n\n\t~(sb-\u003es_blocksize - 1)\n\nis computed as a 32-bit unsigned value (e.g. 0xfffff000 for a 4 KiB\nblock size).  In the AND expression with the 64-bit `ctx-\u003epos`, that\nunsigned operand is zero-extended to 64 bits per the usual arithmetic\nconversions, yielding 0x00000000fffff000.  The high 32 bits of\n`ctx-\u003epos` are silently cleared, even though directory size is\nallowed to exceed 4 GiB.\n\nWhen readdir() crosses the 4 GiB boundary on a 32-bit kernel the\nposition is reset back into the first 4 GiB block, making the\nre-validation path re-enumerate already-returned dirents indefinitely.\n\nThis is ocfs2_dir_foreach_blk_el(), the extent-list readdir path taken\nfor all non-inline directories, so a directory large enough to cross\n4 GiB reaches it.\n\nThis is the same class of bug that commit 3dce5bb82c97 (\"exfat: Fix\nbitwise operation having different size\") fixed in exfat, and the\nfix mirrors the equivalent ext4 fix in this series.  Cast the operand\nto loff_t so the mask is 64-bit before the AND:\n\n\tctx-\u003epos = (ctx-\u003epos \u0026 ~((loff_t)sb-\u003es_blocksize - 1)) | offset;\n\n64-bit kernels are unaffected."
    }
  ],
  "id": "CVE-2026-89490",
  "lastModified": "2026-09-14T13:19:05.950",
  "metrics": {},
  "published": "2026-09-11T20:19:30.810",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1001fb3b69a11eaa0dc7c7428f6edfa48b88997a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1ae7029823ae4c91664cb32eec7fb8dd5e1a337a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/94569154ba49f5f85645d2019c8e206213d8404e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a63308ab426f3a3c7e33b02c150ea59054620261"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b53e2b271eeb6040c2a4a78230c570dc41cdcfa4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c0c165487a2ea5a37ddcdab4259157b7a527129c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c28dc3407937aa8f225942538cd585c9b28ea65a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f9dd5cad8d09110ddff2db1fe756aae93c7552ff"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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