CVE-2025-21654 (GCVE-0-2025-21654)
Vulnerability from cvelistv5 – Published: 2025-01-19 10:18 – Updated: 2025-05-04 07:18
VLAI?
Title
ovl: support encoding fid from inode with no alias
Summary
In the Linux kernel, the following vulnerability has been resolved:
ovl: support encoding fid from inode with no alias
Dmitry Safonov reported that a WARN_ON() assertion can be trigered by
userspace when calling inotify_show_fdinfo() for an overlayfs watched
inode, whose dentry aliases were discarded with drop_caches.
The WARN_ON() assertion in inotify_show_fdinfo() was removed, because
it is possible for encoding file handle to fail for other reason, but
the impact of failing to encode an overlayfs file handle goes beyond
this assertion.
As shown in the LTP test case mentioned in the link below, failure to
encode an overlayfs file handle from a non-aliased inode also leads to
failure to report an fid with FAN_DELETE_SELF fanotify events.
As Dmitry notes in his analyzis of the problem, ovl_encode_fh() fails
if it cannot find an alias for the inode, but this failure can be fixed.
ovl_encode_fh() seldom uses the alias and in the case of non-decodable
file handles, as is often the case with fanotify fid info,
ovl_encode_fh() never needs to use the alias to encode a file handle.
Defer finding an alias until it is actually needed so ovl_encode_fh()
will not fail in the common case of FAN_DELETE_SELF fanotify events.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Affected:
16aac5ad1fa94894b798dd522c5c3a6a0628d7f0 , < f0c0ac84de17c37e6e84da65fb920f91dada55ad
(git)
Affected: 16aac5ad1fa94894b798dd522c5c3a6a0628d7f0 , < 3c7c90274ae339e1ad443c9be1c67a20b80b9c76 (git) Affected: 16aac5ad1fa94894b798dd522c5c3a6a0628d7f0 , < c45beebfde34aa71afbc48b2c54cdda623515037 (git) |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/overlayfs/export.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "f0c0ac84de17c37e6e84da65fb920f91dada55ad",
"status": "affected",
"version": "16aac5ad1fa94894b798dd522c5c3a6a0628d7f0",
"versionType": "git"
},
{
"lessThan": "3c7c90274ae339e1ad443c9be1c67a20b80b9c76",
"status": "affected",
"version": "16aac5ad1fa94894b798dd522c5c3a6a0628d7f0",
"versionType": "git"
},
{
"lessThan": "c45beebfde34aa71afbc48b2c54cdda623515037",
"status": "affected",
"version": "16aac5ad1fa94894b798dd522c5c3a6a0628d7f0",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/overlayfs/export.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.6"
},
{
"lessThan": "6.6",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.74",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.10",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.13",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.74",
"versionStartIncluding": "6.6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.10",
"versionStartIncluding": "6.6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.13",
"versionStartIncluding": "6.6",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\novl: support encoding fid from inode with no alias\n\nDmitry Safonov reported that a WARN_ON() assertion can be trigered by\nuserspace when calling inotify_show_fdinfo() for an overlayfs watched\ninode, whose dentry aliases were discarded with drop_caches.\n\nThe WARN_ON() assertion in inotify_show_fdinfo() was removed, because\nit is possible for encoding file handle to fail for other reason, but\nthe impact of failing to encode an overlayfs file handle goes beyond\nthis assertion.\n\nAs shown in the LTP test case mentioned in the link below, failure to\nencode an overlayfs file handle from a non-aliased inode also leads to\nfailure to report an fid with FAN_DELETE_SELF fanotify events.\n\nAs Dmitry notes in his analyzis of the problem, ovl_encode_fh() fails\nif it cannot find an alias for the inode, but this failure can be fixed.\novl_encode_fh() seldom uses the alias and in the case of non-decodable\nfile handles, as is often the case with fanotify fid info,\novl_encode_fh() never needs to use the alias to encode a file handle.\n\nDefer finding an alias until it is actually needed so ovl_encode_fh()\nwill not fail in the common case of FAN_DELETE_SELF fanotify events."
}
],
"providerMetadata": {
"dateUpdated": "2025-05-04T07:18:19.475Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/f0c0ac84de17c37e6e84da65fb920f91dada55ad"
},
{
"url": "https://git.kernel.org/stable/c/3c7c90274ae339e1ad443c9be1c67a20b80b9c76"
},
{
"url": "https://git.kernel.org/stable/c/c45beebfde34aa71afbc48b2c54cdda623515037"
}
],
"title": "ovl: support encoding fid from inode with no alias",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2025-21654",
"datePublished": "2025-01-19T10:18:11.104Z",
"dateReserved": "2024-12-29T08:45:45.729Z",
"dateUpdated": "2025-05-04T07:18:19.475Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
Loading…