CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's lockd service, specifically in how it handles file handles during the NLMv4 protocol. When an NLMv4 client sends a file handle shorter than the expected size, uninitialized bytes can lead to inconsistent hashing, causing lock-state lookups to fail and potentially allowing unauthorized access or denial of service. Organizations running Linux systems that utilize NLMv4 should prioritize patching this vulnerability to ensure the integrity and reliability of their file locking mechanisms.
Original NVD 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.