FKIE_CVE-2026-53040

Vulnerability from fkie_nvd - Published: 2026-06-24 17:17 - Updated: 2026-06-28 08:16
Severity
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate bg_bits during freefrag scan [BUG] A crafted filesystem can trigger an out-of-bounds bitmap walk when OCFS2_IOC_INFO is issued with OCFS2_INFO_FL_NON_COHERENT. BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline] BUG: KASAN: use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] BUG: KASAN: use-after-free in test_bit_le include/asm-generic/bitops/le.h:21 [inline] BUG: KASAN: use-after-free in ocfs2_info_freefrag_scan_chain fs/ocfs2/ioctl.c:495 [inline] BUG: KASAN: use-after-free in ocfs2_info_freefrag_scan_bitmap fs/ocfs2/ioctl.c:588 [inline] BUG: KASAN: use-after-free in ocfs2_info_handle_freefrag fs/ocfs2/ioctl.c:662 [inline] BUG: KASAN: use-after-free in ocfs2_info_handle_request+0x1c66/0x3370 fs/ocfs2/ioctl.c:754 Read of size 8 at addr ffff888031bce000 by task syz.0.636/1435 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xbe/0x130 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xd1/0x650 mm/kasan/report.c:482 kasan_report+0xfb/0x140 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:186 [inline] kasan_check_range+0x11c/0x200 mm/kasan/generic.c:200 __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31 instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] test_bit_le include/asm-generic/bitops/le.h:21 [inline] ocfs2_info_freefrag_scan_chain fs/ocfs2/ioctl.c:495 [inline] ocfs2_info_freefrag_scan_bitmap fs/ocfs2/ioctl.c:588 [inline] ocfs2_info_handle_freefrag fs/ocfs2/ioctl.c:662 [inline] ocfs2_info_handle_request+0x1c66/0x3370 fs/ocfs2/ioctl.c:754 ocfs2_info_handle+0x18d/0x2a0 fs/ocfs2/ioctl.c:828 ocfs2_ioctl+0x632/0x6e0 fs/ocfs2/ioctl.c:913 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x197/0x1e0 fs/ioctl.c:583 ... [CAUSE] ocfs2_info_freefrag_scan_chain() uses on-disk bg_bits directly as the bitmap scan limit. The coherent path reads group descriptors through ocfs2_read_group_descriptor(), which validates the descriptor before use. The non-coherent path uses ocfs2_read_blocks_sync() instead and skips that validation, so an impossible bg_bits value can drive the bitmap walk past the end of the block. [FIX] Compute the bitmap capacity from the filesystem format with ocfs2_group_bitmap_size(), report descriptors whose bg_bits exceeds that limit, and clamp the scan to the computed capacity. This keeps the freefrag report going while avoiding reads beyond the buffer.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/05d0cbea41167b6b061c6ba5b70ee5a9a7a24c9e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0998674eec138c55e9e349b9cbd9dbc5129a9cc8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3e167e230d19cd273108bab2e4c61800fc335ae8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4c2d62ddde8928db12f4608950b67a20e67deab2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8f687eeed3da3012152b0f9473f578869de0cd7b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bb2906a1065ec28de021bac2ed03f2624edd7d07
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bb3c54d1e71578521111f1a1ee7d5f4761a242b8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e0dcf12665d6dde37facf790803cdad44d5c328c
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ocfs2/ioctl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bb2906a1065ec28de021bac2ed03f2624edd7d07",
              "status": "affected",
              "version": "d24a10b9f8ed548981696cd36e2b4f16e6f360b1",
              "versionType": "git"
            },
            {
              "lessThan": "3e167e230d19cd273108bab2e4c61800fc335ae8",
              "status": "affected",
              "version": "d24a10b9f8ed548981696cd36e2b4f16e6f360b1",
              "versionType": "git"
            },
            {
              "lessThan": "0998674eec138c55e9e349b9cbd9dbc5129a9cc8",
              "status": "affected",
              "version": "d24a10b9f8ed548981696cd36e2b4f16e6f360b1",
              "versionType": "git"
            },
            {
              "lessThan": "bb3c54d1e71578521111f1a1ee7d5f4761a242b8",
              "status": "affected",
              "version": "d24a10b9f8ed548981696cd36e2b4f16e6f360b1",
              "versionType": "git"
            },
            {
              "lessThan": "05d0cbea41167b6b061c6ba5b70ee5a9a7a24c9e",
              "status": "affected",
              "version": "d24a10b9f8ed548981696cd36e2b4f16e6f360b1",
              "versionType": "git"
            },
            {
              "lessThan": "4c2d62ddde8928db12f4608950b67a20e67deab2",
              "status": "affected",
              "version": "d24a10b9f8ed548981696cd36e2b4f16e6f360b1",
              "versionType": "git"
            },
            {
              "lessThan": "e0dcf12665d6dde37facf790803cdad44d5c328c",
              "status": "affected",
              "version": "d24a10b9f8ed548981696cd36e2b4f16e6f360b1",
              "versionType": "git"
            },
            {
              "lessThan": "8f687eeed3da3012152b0f9473f578869de0cd7b",
              "status": "affected",
              "version": "d24a10b9f8ed548981696cd36e2b4f16e6f360b1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ocfs2/ioctl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.0"
            },
            {
              "lessThan": "3.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.258",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.209",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.141",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.91",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.33",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "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: validate bg_bits during freefrag scan\n\n[BUG]\nA crafted filesystem can trigger an out-of-bounds bitmap walk when\nOCFS2_IOC_INFO is issued with OCFS2_INFO_FL_NON_COHERENT.\n\nBUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]\nBUG: KASAN: use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]\nBUG: KASAN: use-after-free in test_bit_le include/asm-generic/bitops/le.h:21 [inline]\nBUG: KASAN: use-after-free in ocfs2_info_freefrag_scan_chain fs/ocfs2/ioctl.c:495 [inline]\nBUG: KASAN: use-after-free in ocfs2_info_freefrag_scan_bitmap fs/ocfs2/ioctl.c:588 [inline]\nBUG: KASAN: use-after-free in ocfs2_info_handle_freefrag fs/ocfs2/ioctl.c:662 [inline]\nBUG: KASAN: use-after-free in ocfs2_info_handle_request+0x1c66/0x3370 fs/ocfs2/ioctl.c:754\nRead of size 8 at addr ffff888031bce000 by task syz.0.636/1435\nCall Trace:\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0xbe/0x130 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xd1/0x650 mm/kasan/report.c:482\n kasan_report+0xfb/0x140 mm/kasan/report.c:595\n check_region_inline mm/kasan/generic.c:186 [inline]\n kasan_check_range+0x11c/0x200 mm/kasan/generic.c:200\n __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31\n instrument_atomic_read include/linux/instrumented.h:68 [inline]\n _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]\n test_bit_le include/asm-generic/bitops/le.h:21 [inline]\n ocfs2_info_freefrag_scan_chain fs/ocfs2/ioctl.c:495 [inline]\n ocfs2_info_freefrag_scan_bitmap fs/ocfs2/ioctl.c:588 [inline]\n ocfs2_info_handle_freefrag fs/ocfs2/ioctl.c:662 [inline]\n ocfs2_info_handle_request+0x1c66/0x3370 fs/ocfs2/ioctl.c:754\n ocfs2_info_handle+0x18d/0x2a0 fs/ocfs2/ioctl.c:828\n ocfs2_ioctl+0x632/0x6e0 fs/ocfs2/ioctl.c:913\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:597 [inline]\n __se_sys_ioctl fs/ioctl.c:583 [inline]\n __x64_sys_ioctl+0x197/0x1e0 fs/ioctl.c:583\n ...\n\n[CAUSE]\nocfs2_info_freefrag_scan_chain() uses on-disk bg_bits directly as the\nbitmap scan limit. The coherent path reads group descriptors through\nocfs2_read_group_descriptor(), which validates the descriptor before\nuse. The non-coherent path uses ocfs2_read_blocks_sync() instead and\nskips that validation, so an impossible bg_bits value can drive the\nbitmap walk past the end of the block.\n\n[FIX]\nCompute the bitmap capacity from the filesystem format with\nocfs2_group_bitmap_size(), report descriptors whose bg_bits exceeds\nthat limit, and clamp the scan to the computed capacity. This keeps the\nfreefrag report going while avoiding reads beyond the buffer."
    }
  ],
  "id": "CVE-2026-53040",
  "lastModified": "2026-06-28T08:16:30.603",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-06-24T17:17:15.687",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/05d0cbea41167b6b061c6ba5b70ee5a9a7a24c9e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0998674eec138c55e9e349b9cbd9dbc5129a9cc8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3e167e230d19cd273108bab2e4c61800fc335ae8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4c2d62ddde8928db12f4608950b67a20e67deab2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8f687eeed3da3012152b0f9473f578869de0cd7b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bb2906a1065ec28de021bac2ed03f2624edd7d07"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bb3c54d1e71578521111f1a1ee7d5f4761a242b8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e0dcf12665d6dde37facf790803cdad44d5c328c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}


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