GHSA-5684-4XFG-MXJ4
Vulnerability from github – Published: 2024-11-09 12:30 – Updated: 2025-04-11 04:19In 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:
-
Attach image_1 to loop0, attach image_2 to loop1, and scan btrfs devices by ioctl(BTRFS_IOC_SCAN_DEV):
/ btrfs_device_1 → loop0fs_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)
-
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().
{
"affected": [],
"aliases": [
"CVE-2024-50217"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-11-09T11:15:07Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix use-after-free of block device file in __btrfs_free_extra_devids()\n\nMounting btrfs from two images (which have the same one fsid and two\ndifferent dev_uuids) in certain executing order may trigger an UAF for\nvariable \u0027device-\u003ebdev_file\u0027 in __btrfs_free_extra_devids(). And\nfollowing are the details:\n\n1. Attach image_1 to loop0, attach image_2 to loop1, and scan btrfs\n devices by ioctl(BTRFS_IOC_SCAN_DEV):\n\n / btrfs_device_1 \u2192 loop0\n fs_device\n \\ btrfs_device_2 \u2192 loop1\n2. mount /dev/loop0 /mnt\n btrfs_open_devices\n btrfs_device_1-\u003ebdev_file = btrfs_get_bdev_and_sb(loop0)\n btrfs_device_2-\u003ebdev_file = btrfs_get_bdev_and_sb(loop1)\n btrfs_fill_super\n open_ctree\n fail: btrfs_close_devices // -ENOMEM\n\t btrfs_close_bdev(btrfs_device_1)\n fput(btrfs_device_1-\u003ebdev_file)\n\t // btrfs_device_1-\u003ebdev_file is freed\n\t btrfs_close_bdev(btrfs_device_2)\n fput(btrfs_device_2-\u003ebdev_file)\n\n3. mount /dev/loop1 /mnt\n btrfs_open_devices\n btrfs_get_bdev_and_sb(\u0026bdev_file)\n // EIO, btrfs_device_1-\u003ebdev_file is not assigned,\n // which points to a freed memory area\n btrfs_device_2-\u003ebdev_file = btrfs_get_bdev_and_sb(loop1)\n btrfs_fill_super\n open_ctree\n btrfs_free_extra_devids\n if (btrfs_device_1-\u003ebdev_file)\n fput(btrfs_device_1-\u003ebdev_file) // UAF !\n\nFix it by setting \u0027device-\u003ebdev_file\u0027 as \u0027NULL\u0027 after closing the\nbtrfs_device in btrfs_close_one_device().",
"id": "GHSA-5684-4xfg-mxj4",
"modified": "2025-04-11T04:19:27Z",
"published": "2024-11-09T12:30:47Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-50217"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/47a83f8df39545f3f552bb6a1b6d9c30e37621dd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/aec8e6bf839101784f3ef037dcdb9432c3f32343"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2025/04/10/4"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2025/04/10/5"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2025/04/10/6"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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