Debian: CVE-2024-40943: linux, linux-6.1 -- security update

Debian: CVE-2024-40943: linux, linux-6.1 -- security update

Severity

4

CVSS

(AV:L/AC:M/Au:N/C:P/I:P/A:P)

Published

07/12/2024

Created

07/17/2024

Added

07/17/2024

Modified

01/03/2025

Description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix races between hole punching and AIO+DIO After commit "ocfs2: return real error code in ocfs2_dio_wr_get_block", fstests/generic/300 become from always failed to sometimes failed: ======================================================================== [473.293420 ] run fstests generic/300 [475.296983 ] JBD2: Ignoring recovery information on journal [475.302473 ] ocfs2: Mounting device (253,1) on (node local, slot 0) with ordered data mode. [494.290998 ] OCFS2: ERROR (device dm-1): ocfs2_change_extent_flag: Owner 5668 has an extent at cpos 78723 which can no longer be found [494.291609 ] On-disk corruption discovered. Please run fsck.ocfs2 once the filesystem is unmounted. [494.292018 ] OCFS2: File system is now read-only. [494.292224 ] (kworker/19:11,2628,19):ocfs2_mark_extent_written:5272 ERROR: status = -30 [494.292602 ] (kworker/19:11,2628,19):ocfs2_dio_end_io_write:2374 ERROR: status = -3 fio: io_u error on file /mnt/scratch/racer: Read-only file system: write offset=460849152, buflen=131072 ========================================================================= In __blockdev_direct_IO, ocfs2_dio_wr_get_block is called to add unwritten extents to a list.extents are also inserted into extent tree in ocfs2_write_begin_nolock.Then another thread call fallocate to puch a hole at one of the unwritten extent.The extent at cpos was removed by ocfs2_remove_extent().At end io worker thread, ocfs2_search_extent_list found there is no such extent at the cpos. T1T2T3 inode lock ... insert extents ... inode unlock ocfs2_fallocate __ocfs2_change_file_space inode lock lock ip_alloc_sem ocfs2_remove_inode_range inode ocfs2_remove_btree_range ocfs2_remove_extent ^---remove the extent at cpos 78723 ... unlock ip_alloc_sem inode unlock ocfs2_dio_end_io ocfs2_dio_end_io_write lock ip_alloc_sem ocfs2_mark_extent_written ocfs2_change_extent_flag ocfs2_search_extent_list ^---failed to find extent ... unlock ip_alloc_sem In most filesystems, fallocate is not compatible with racing with AIO+DIO, so fix it by adding to wait for all dio before fallocate/punch_hole like ext4.

Solution(s)

• debian-upgrade-linux
• debian-upgrade-linux-6-1

References

• https://attackerkb.com/topics/cve-2024-40943
• CVE - 2024-40943
• DSA-5730-1