ghsa-xggq-vrr8-pfwp
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
fs: don't misleadingly warn during thaw operations
The block device may have been frozen before it was claimed by a filesystem. Concurrently another process might try to mount that frozen block device and has temporarily claimed the block device for that purpose causing a concurrent fs_bdev_thaw() to end up here. The mounter is already about to abort mounting because they still saw an elevanted bdev->bd_fsfreeze_count so get_bdev_super() will return NULL in that case.
For example, P1 calls dm_suspend() which calls into bdev_freeze() before the block device has been claimed by the filesystem. This brings bdev->bd_fsfreeze_count to 1 and no call into fs_bdev_freeze() is required.
Now P2 tries to mount that frozen block device. It claims it and checks bdev->bd_fsfreeze_count. As it's elevated it aborts mounting.
In the meantime P3 called dm_resume(). P3 sees that the block device is already claimed by a filesystem and calls into fs_bdev_thaw().
P3 takes a passive reference and realizes that the filesystem isn't ready yet. P3 puts itself to sleep to wait for the filesystem to become ready.
P2 now puts the last active reference to the filesystem and marks it as dying. P3 gets woken, sees that the filesystem is dying and get_bdev_super() fails.
{
"affected": [],
"aliases": [
"CVE-2024-42149"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-07-30T08:15:06Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs: don\u0027t misleadingly warn during thaw operations\n\nThe block device may have been frozen before it was claimed by a\nfilesystem. Concurrently another process might try to mount that\nfrozen block device and has temporarily claimed the block device for\nthat purpose causing a concurrent fs_bdev_thaw() to end up here. The\nmounter is already about to abort mounting because they still saw an\nelevanted bdev-\u003ebd_fsfreeze_count so get_bdev_super() will return\nNULL in that case.\n\nFor example, P1 calls dm_suspend() which calls into bdev_freeze() before\nthe block device has been claimed by the filesystem. This brings\nbdev-\u003ebd_fsfreeze_count to 1 and no call into fs_bdev_freeze() is\nrequired.\n\nNow P2 tries to mount that frozen block device. It claims it and checks\nbdev-\u003ebd_fsfreeze_count. As it\u0027s elevated it aborts mounting.\n\nIn the meantime P3 called dm_resume(). P3 sees that the block device is\nalready claimed by a filesystem and calls into fs_bdev_thaw().\n\nP3 takes a passive reference and realizes that the filesystem isn\u0027t\nready yet. P3 puts itself to sleep to wait for the filesystem to become\nready.\n\nP2 now puts the last active reference to the filesystem and marks it as\ndying. P3 gets woken, sees that the filesystem is dying and\nget_bdev_super() fails.",
"id": "GHSA-xggq-vrr8-pfwp",
"modified": "2024-12-10T00:31:26Z",
"published": "2024-07-30T09:32:02Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-42149"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/25b1e3906e050d452427bc51620bb7f0a591373a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2ae4db5647d807efb6a87c09efaa6d1db9c905d7"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.