ext2/dax: Fix ext2_setsize when len is page aligned

{
  "id": "aba84347ddc778bb20742730f0a1486f1b265fd467dc49f6905e37558f50b981",
  "url": "https://osv.dev/vulnerability/CVE-2023-53323",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ext2/dax: Fix ext2_setsize when len is page aligned",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ext2/dax: Fix ext2_setsize when len is page aligned PAGE_ALIGN(x) macro gives the next highest value which is multiple of pagesize. But if x is already page aligned then it simply returns x. So, if x passed is 0 in dax_zero_range() function, that means the length gets passed as 0 to ->iomap_begin(). In ext2 it then calls ext2_get_blocks -> max_blocks as 0 and hits bug_on here in ext2_get_blocks(). BUG_ON(maxblocks == 0); Instead we should be calling dax_truncate_page() here which takes care of it. i.e. it only calls dax_zero_range if the offset is not page/block aligned. This can be easily triggered with following on fsdax mounted pmem device. dd if=/dev/zero of=file count=1 bs=512 truncate -s 0 file [79.525838] EXT2-fs (pmem0): DAX enabled. Warning: EXPERIMENTAL, use at your own risk [79.529376] ext2 filesystem being mounted at /mnt1/test supports timestamps until 2038 (0x7fffffff) [93.793207] ------------[ cut here ]------------ [93.795102] kernel BUG at fs/ext2/inode.c:637! [93.796904] invalid opcode: 0000 [#1] PREEMPT SMP PTI [93.798659] CPU: 0 PID: 1192 Comm: truncate Not tainted 6.3.0-rc2-xfstests-00056-g131086faa369 #139 [93.806459] RIP: 0010:ext2_get_blocks.constprop.0+0x524/0x610 <...> [93.835298] Call Trace: [93.836253] [93.837103] ? lock_acquire+0xf8/0x110 [93.838479] ? d_lookup+0x69/0xd0 [93.839779] ext2_iomap_begin+0xa7/0x1c0 [93.841154] iomap_iter+0xc7/0x150 [93.842425] dax_zero_range+0x6e/0xa0 ",
    "evidence": "osv:CVE-2023-53323",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.4.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2023-53323",
      "aliases": [
        "CVE-2023-53323"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "2aa3048e03d38d5358be2553d4b638c1a018498c"
                },
                {
                  "fixed": "9e54fd14bd143c261e52fde74355e85e9526c58c"
                },
                {
                  "fixed": "5cee8bfb8cbd99c97aff85d2bf066b6a496e13ab"
                },
                {
                  "fixed": "fcced95b6ba2a507a83b8b3e0358a8ac16b13e35"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53323.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.15.0"
                },
                {
                  "fixed": "6.1.40"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.4.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53323.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:28.535800699Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/5cee8bfb8cbd99c97aff85d2bf066b6a496e13ab",
        "https://git.kernel.org/stable/c/9e54fd14bd143c261e52fde74355e85e9526c58c",
        "https://git.kernel.org/stable/c/fcced95b6ba2a507a83b8b3e0358a8ac16b13e35",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53323.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-53323",
        "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/2023/53xxx/CVE-2023-53323.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-53323",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 495044,
  "published_at": "2025-09-16T16:11:58.877+00:00"
}