ceph: properly decrypt filenames in vmalloc() buffers
In the Linux kernel, the following vulnerability has been resolved: ceph: properly decrypt filenames in vmalloc() buffers The fscrypt subsystem uses the scatterlist crypto API, inheriting its requirement that any buffers are in the linear mapping region. However, the messenger client uses kvmalloc() to create buffers for messages, which will occasionally place those buffers in the vmalloc() region when physical memory fragmentation doesn't permit a large enough kmalloc(). The various callers of ceph_fname_to_usr() directly pass (slices of) raw messages from the MDS without considering that the messages may be in vmalloc() buffers, resulting in oopses especially on non-x86 platforms (see 'Closes:' for more details and a reproducer). Make ceph_fname_to_usr() explicitly tolerant of vmalloc()-allocated fname->ctext, fname->name, and/or oname->name buffers, using `tname` (which, when non-null, must be a linear address; when null, is briefly allocated as necessary) as a bounce buffer to avoid passing any inappropriate addresses to fscrypt_fname_disk_to_usr(). Additionally change parse_reply_info_readdir() -- the only function to supply its own `tname` -- to follow the new "tname must never come from vmalloc()" rule by passing NULL when the message is not in the linear region. Though this causes a per-dentry kmalloc()+kfree(), this overhead exists only when processing the minority of messages that spill into vmalloc(). My (crude) testing puts this at only about 1 in 8,000 readdir me
CVE-2026-90042
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-90042
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "457117f077c6749d1e28469eae91fb69c9806768",
"lessThan": "23c5cc9652c6ee85617002cb66e1068395045de6",
"versionType": "git"
},
{
"status": "affected",
"version": "457117f077c6749d1e28469eae91fb69c9806768",
"lessThan": "93729594af506557a86f8b603be7ac5f3370eeca",
"versionType": "git"
},
{
"status": "affected",
"version": "457117f077c6749d1e28469eae91fb69c9806768",
"lessThan": "110747ff535e3d98ac17d68dbd056bb6ef000e23",
"versionType": "git"
},
{
"status": "affected",
"version": "457117f077c6749d1e28469eae91fb69c9806768",
"lessThan": "3b467c68803d7c7e82678289e598afd44faa6101",
"versionType": "git"
},
{
"status": "affected",
"version": "457117f077c6749d1e28469eae91fb69c9806768",
"lessThan": "e939fc6a7bd969a58a150b7f188c1047138403e3",
"versionType": "git"
}
],
"programFiles": [
"fs/ceph/crypto.c",
"fs/ceph/mds_client.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.6"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.6",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.51",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/ceph/crypto.c",
"fs/ceph/mds_client.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-90042
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #48588 · Revision 1
- Added to Heist Feed
- Publisher date