lockd: Avoid hashing uninitialized bytes in nlm4svc_lookup_file()
file_hash() digests the first LOCKD_FH_HASH_SIZE bytes of
nfs_fh.data when bucketing nlm_files[], independent of fh.size.
Commit 3de744ee4e45 ("lockd: Use xdrgen XDR functions for the
NLMv4 TEST procedure") set .pc_argzero to zero for the converted
procedures and moved file-handle population into
nlm4svc_lookup_file(), which copies only xdr_lock->fh.len bytes
into lock->fh.data.
When an NLMv4 client presents a file handle shorter than
LOCKD_FH_HASH_SIZE, bytes fh.len..31 retain whatever the argument
buffer held from an earlier request. The same wire handle then
hashes to different buckets across calls; nlm_lookup_file() misses
the existing nlm_file entry, and lock-state lookups fail.
Zero only the tail bytes that file_hash() would otherwise consume.
Handles of LOCKD_FH_HASH_SIZE or larger already populate every byte
that file_hash() reads.
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
No data available yet.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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Sat, 15 Aug 2026 06:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: lockd: Avoid hashing uninitialized bytes in nlm4svc_lookup_file() file_hash() digests the first LOCKD_FH_HASH_SIZE bytes of nfs_fh.data when bucketing nlm_files[], independent of fh.size. Commit 3de744ee4e45 ("lockd: Use xdrgen XDR functions for the NLMv4 TEST procedure") set .pc_argzero to zero for the converted procedures and moved file-handle population into nlm4svc_lookup_file(), which copies only xdr_lock->fh.len bytes into lock->fh.data. When an NLMv4 client presents a file handle shorter than LOCKD_FH_HASH_SIZE, bytes fh.len..31 retain whatever the argument buffer held from an earlier request. The same wire handle then hashes to different buckets across calls; nlm_lookup_file() misses the existing nlm_file entry, and lock-state lookups fail. Zero only the tail bytes that file_hash() would otherwise consume. Handles of LOCKD_FH_HASH_SIZE or larger already populate every byte that file_hash() reads. | |
| Title | lockd: Avoid hashing uninitialized bytes in nlm4svc_lookup_file() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-15T05:58:13.504Z
Reserved: 2026-08-15T05:44:03.883Z
Link: CVE-2026-74315
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-08-15T06:22:31.763
Modified: 2026-08-15T06:22:31.763
Link: CVE-2026-74315
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.