Description
In the Linux kernel, the following vulnerability has been resolved: nilfs2: Fix potential block overflow that cause system hang When a user executes the FITRIM command, an underflow can occur when calculating nblocks if end_block is too small. Since nblocks is of type sector_t, which is u64, a negative nblocks value will become a very large positive integer. This ultimately leads to the block layer function __blkdev_issue_discard() taking an excessively long time to process the bio chain, and the ns_segctor_sem lock remains held for a long period. This prevents other tasks from acquiring the ns_segctor_sem lock, resulting in the hang reported by syzbot in [1]. If the ending block is too small, typically if it is smaller than 4KiB range, depending on the usage of the segment 0, it may be possible to attempt a discard request beyond the device size causing the hang. Exiting successfully and assign the discarded size (0 in this case) to range->len. Although the start and len values in the user input range are too small, a conservative strategy is adopted here to safely ignore them, which is equivalent to a no-op; it will not perform any trimming and will not throw an error. [1] task:segctord state:D stack:28968 pid:6093 tgid:6093 ppid:2 task_flags:0x200040 flags:0x00080000 Call Trace: rwbase_write_lock+0x3dd/0x750 kernel/locking/rwbase_rt.c:272 nilfs_transaction_lock+0x253/0x4c0 fs/nilfs2/segment.c:357 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2569 [inline] nilfs_segctor_thread+0x6ec/0xe00 fs/nilfs2/segment.c:2684 [ryusuke: corrected part of the commit message about the consequences]
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
82e11e857be3ffd2a0a952c9db8aa2379e2b9e44 to < 6457d3ee41a4c15082ac49c5aa7fb933b4a043f3affected82e11e857be3ffd2a0a952c9db8aa2379e2b9e44 to < ba18e5f22f26aa4ef78bc3e81f639d1d4f3845e6affected82e11e857be3ffd2a0a952c9db8aa2379e2b9e44 to < 2438982f635e6cc2009be68ba2efb2998727d8d4affected82e11e857be3ffd2a0a952c9db8aa2379e2b9e44 to < df1e20796c9f3d541cca47fb72e4369ea135642daffected82e11e857be3ffd2a0a952c9db8aa2379e2b9e44 to < ea2278657ad0d62596589fbe2caf995e189e65e7affected82e11e857be3ffd2a0a952c9db8aa2379e2b9e44 to < 4aa45f841413cca81882602b4042c53502f34cadaffected82e11e857be3ffd2a0a952c9db8aa2379e2b9e44 to < b8c5ee234bd54f1447c846101fdaef2cf70c2149affected82e11e857be3ffd2a0a952c9db8aa2379e2b9e44 to < ed527ef0c264e4bed6c7b2a158ddf516b17f5f66affected
Linux Linux
Default version status: affected
3.15affected0 to < 3.15unaffected5.10.251 to ≤ 5.10.*unaffected5.15.201 to ≤ 5.15.*unaffected6.1.164 to ≤ 6.1.*unaffected6.6.125 to ≤ 6.6.*unaffected6.12.72 to ≤ 6.12.*unaffected6.18.11 to ≤ 6.18.*unaffected6.19.1 to ≤ 6.19.*unaffected7.0 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/6457d3ee41a4c15082ac49c5aa7fb933b4a043f3 ↗
- https://git.kernel.org/stable/c/ba18e5f22f26aa4ef78bc3e81f639d1d4f3845e6 ↗
- https://git.kernel.org/stable/c/2438982f635e6cc2009be68ba2efb2998727d8d4 ↗
- https://git.kernel.org/stable/c/df1e20796c9f3d541cca47fb72e4369ea135642d ↗
- https://git.kernel.org/stable/c/ea2278657ad0d62596589fbe2caf995e189e65e7 ↗
- https://git.kernel.org/stable/c/4aa45f841413cca81882602b4042c53502f34cad ↗
- https://git.kernel.org/stable/c/b8c5ee234bd54f1447c846101fdaef2cf70c2149 ↗
- https://git.kernel.org/stable/c/ed527ef0c264e4bed6c7b2a158ddf516b17f5f66 ↗