4.7

CVE-2024-40943

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.
Verknüpft mit AI von unstrukturierten Daten zu bestehenden CPE der NVD
Diese Information steht angemeldeten Benutzern zur Verfügung. Login Login
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 2.6.23 < 4.19.317
Linux ≫ Linux Kernel Version >= 4.20 < 5.4.279
Linux ≫ Linux Kernel Version >= 5.5 < 5.10.221
Linux ≫ Linux Kernel Version >= 5.11 < 5.15.162
Linux ≫ Linux Kernel Version >= 5.16 < 6.1.95
Linux ≫ Linux Kernel Version >= 6.2 < 6.6.35
Linux ≫ Linux Kernel Version >= 6.7 < 6.9.6
Zu dieser CVE wurde keine CISA KEV oder CERT.AT-Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.01% 0.005
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 4.7 1 3.6
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.