What is the CVSS score of CVE-2024-40943?

CVE-2024-40943 has a CVSS 3.1 base score of 4.7 (Medium). CVSS vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.2%.

Is there a patch available for CVE-2024-40943?

Yes, a patch is available for CVE-2024-40943. Update the affected software to the latest version immediately.

Linux Kernel CVE-2024-40943

MEDIUM

Race Condition (CWE-362)

2024-07-12 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Race Condition Information Disclosure Linux Linux Kernel

4.7

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

4.7 MEDIUM

AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Local

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

CVE Published

Jul 12, 2024 - 13:15 nvd

MEDIUM 4.7

DescriptionNVD

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.

T1 T2 T3 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.

AnalysisAI

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",. Rated medium severity (CVSS 4.7).

Technical ContextAI

This vulnerability is classified under CWE-362. 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. T1 T2 T3 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. Affected products include: Linux Linux Kernel.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.