btrfs: fix use-after-free of block device file in __btrfs_free_extra_devids()

{
  "id": "6914f70c338cbc23ba6655d1ec8b0681f08433b7bdb4ad5ca372ef67b8d37cb9",
  "url": "https://osv.dev/vulnerability/CVE-2024-50217",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "btrfs: fix use-after-free of block device file in __btrfs_free_extra_devids()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free of block device file in __btrfs_free_extra_devids() Mounting btrfs from two images (which have the same one fsid and two different dev_uuids) in certain executing order may trigger an UAF for variable 'device->bdev_file' in __btrfs_free_extra_devids(). And following are the details: 1. Attach image_1 to loop0, attach image_2 to loop1, and scan btrfs devices by ioctl(BTRFS_IOC_SCAN_DEV): / btrfs_device_1 → loop0 fs_device \\ btrfs_device_2 → loop1 2. mount /dev/loop0 /mnt btrfs_open_devices btrfs_device_1->bdev_file = btrfs_get_bdev_and_sb(loop0) btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1) btrfs_fill_super open_ctree fail: btrfs_close_devices // -ENOMEM btrfs_close_bdev(btrfs_device_1) fput(btrfs_device_1->bdev_file) // btrfs_device_1->bdev_file is freed btrfs_close_bdev(btrfs_device_2) fput(btrfs_device_2->bdev_file) 3. mount /dev/loop1 /mnt btrfs_open_devices btrfs_get_bdev_and_sb(&bdev_file) // EIO, btrfs_device_1->bdev_file is not assigned, // which points to a freed memory area btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1) btrfs_fill_super open_ctree btrfs_free_extra_devids if (btrfs_device_1->bdev_file) fput(btrfs_device_1->bdev_file) // UAF ! Fix it by setting 'device->bdev_file' as 'NULL' after closing the btrfs_device in btrfs_close_one_device().",
    "evidence": "osv:CVE-2024-50217",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.11.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2024-50217",
      "aliases": [
        "CVE-2024-50217"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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": [
                {
                  "introduced": "142388194191a3edc9ba01cfcfd8b691e0971fb2"
                },
                {
                  "fixed": "47a83f8df39545f3f552bb6a1b6d9c30e37621dd"
                },
                {
                  "fixed": "aec8e6bf839101784f3ef037dcdb9432c3f32343"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50217.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.8.0"
                },
                {
                  "fixed": "6.11.7"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-50217.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.475854434Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/47a83f8df39545f3f552bb6a1b6d9c30e37621dd",
        "https://git.kernel.org/stable/c/aec8e6bf839101784f3ef037dcdb9432c3f32343",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50217.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-50217",
        "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/2024/50xxx/CVE-2024-50217.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-50217",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 491776,
  "published_at": "2024-11-09T10:14:28.798+00:00"
}