Description (CNA)
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.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected e05df3b115e7308afbca652769b54e4549fcc723 before 0645fa4d48e9b77d93f8b7a1c1fea58a97c2f8b0; affected e05df3b115e7308afbca652769b54e4549fcc723 before 9fd3bcb54a6afea5fa8a828d010561143560b7c5; affected e05df3b115e7308afbca652769b54e4549fcc723 before cb06a07d835ba1ea250785a796243bb483e65816; affected e05df3b115e7308afbca652769b54e4549fcc723 before 20cedb4d9f6b230d0ee469690b8f868f06a07c29; affected e05df3b115e7308afbca652769b54e4549fcc723 before 238e14eb7226f883b72caccd2d37bf5707df066b |
| Linux / Linux | affected 3.8; unaffected 0 before 3.8; unaffected 6.6.160 through 6.6.*; unaffected 6.12.114 through 6.12.*; unaffected 6.18.57 through 6.18.*; unaffected 7.0.10 through 7.0.*; unaffected 7.1 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/0645fa4d48e9b77d93f8b7a1c1fea58a97c2f8b0
- https://git.kernel.org/stable/c/9fd3bcb54a6afea5fa8a828d010561143560b7c5
- https://git.kernel.org/stable/c/cb06a07d835ba1ea250785a796243bb483e65816
- https://git.kernel.org/stable/c/20cedb4d9f6b230d0ee469690b8f868f06a07c29
- https://git.kernel.org/stable/c/238e14eb7226f883b72caccd2d37bf5707df066b