f2fs: fix data loss caused by incorrect use of nat_entry flag
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.6.160, 6.12.114, 6.18.57, 7.0.10
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix data loss caused by incorrect use of nat_entry flag Data loss can occur when fsync is performed on a newly created file (before any checkpoint has been written) concurrently with a checkpoint operation. The scenario is as follows: create & write & fsync 'file A' write checkpoint • f2fs_do_sync_file // inline inode • f2fs_write_inode // inode folio is dirty • f2fs_write_checkpoint • f2fs_flush_merged_writes • f2fs_sync_node_pages • f2fs_flush_nat_entries • f2fs_fsync_node_pages // no dirty node • f2fs_need_inode_block_update // return false SPO and lost 'file A' f2fs_flush_nat_entries() sets the IS_CHECKPOINTED and HAS_LAST_FSYNC flags for the nat_entry, but this does not mean that the checkpoint has actually completed successfully. However, f2fs_need_inode_block_update() checks these flags and incorrectly assumes that the checkpoint has finished. The root cause is that the semantics of IS_CHECKPOINTED and HAS_LAST_FSYNC are only guaranteed after the checkpoint write fully completes. This patch modifies f2fs_need_inode_block_update() to acquire the sbi->node_write lock before reading the nat_entry flags, ensuring that once IS_CHECKPOINTED and HAS_LAST_FSYNC are observed to be set, the checkpoint operation has already completed.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From e05df3b115e7308afbca652769b54e4549fcc723 · fixed in 0645fa4d48e9b77d93f8b7a1c1fea58a97c2f8b0; From e05df3b115e7308afbca652769b54e4549fcc723 · fixed in 9fd3bcb54a6afea5fa8a828d010561143560b7c5; From e05df3b115e7308afbca652769b54e4549fcc723 · fixed in cb06a07d835ba1ea250785a796243bb483e65816; From e05df3b115e7308afbca652769b54e4549fcc723 · fixed in 20cedb4d9f6b230d0ee469690b8f868f06a07c29; From e05df3b115e7308afbca652769b54e4549fcc723 · fixed in 238e14eb7226f883b72caccd2d37bf5707df066b
- Linux Linux
3.8
- KernelLinux
From 3.8.0 · fixed in 6.6.160; From 6.7.0 · fixed in 6.12.114; From 6.13.0 · fixed in 6.18.57; From 6.19.0 · fixed in 7.0.10