Debian: CVE-2024-50265: linux, linux-6.1 -- security update

Debian: CVE-2024-50265: linux, linux-6.1 -- security update

Severity

5

CVSS

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

Published

11/19/2024

Created

12/03/2024

Added

12/02/2024

Modified

01/30/2025

Description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: remove entry once instead of null-ptr-dereference in ocfs2_xa_remove() Syzkaller is able to provoke null-ptr-dereference in ocfs2_xa_remove(): [ 57.319872] (a.out,1161,7):ocfs2_xa_remove:2028 ERROR: status = -12 [ 57.320420] (a.out,1161,7):ocfs2_xa_cleanup_value_truncate:1999 ERROR: Partial truncate while removing xattr overlay.upper.Leaking 1 clusters and removing the entry [ 57.321727] BUG: kernel NULL pointer dereference, address: 0000000000000004 [...] [ 57.325727] RIP: 0010:ocfs2_xa_block_wipe_namevalue+0x2a/0xc0 [...] [ 57.331328] Call Trace: [ 57.331477]<TASK> [...] [ 57.333511]? do_user_addr_fault+0x3e5/0x740 [ 57.333778]? exc_page_fault+0x70/0x170 [ 57.334016]? asm_exc_page_fault+0x2b/0x30 [ 57.334263]? __pfx_ocfs2_xa_block_wipe_namevalue+0x10/0x10 [ 57.334596]? ocfs2_xa_block_wipe_namevalue+0x2a/0xc0 [ 57.334913]ocfs2_xa_remove_entry+0x23/0xc0 [ 57.335164]ocfs2_xa_set+0x704/0xcf0 [ 57.335381]? _raw_spin_unlock+0x1a/0x40 [ 57.335620]? ocfs2_inode_cache_unlock+0x16/0x20 [ 57.335915]? trace_preempt_on+0x1e/0x70 [ 57.336153]? start_this_handle+0x16c/0x500 [ 57.336410]? preempt_count_sub+0x50/0x80 [ 57.336656]? _raw_read_unlock+0x20/0x40 [ 57.336906]? start_this_handle+0x16c/0x500 [ 57.337162]ocfs2_xattr_block_set+0xa6/0x1e0 [ 57.337424]__ocfs2_xattr_set_handle+0x1fd/0x5d0 [ 57.337706]? ocfs2_start_trans+0x13d/0x290 [ 57.337971]ocfs2_xattr_set+0xb13/0xfb0 [ 57.338207]? dput+0x46/0x1c0 [ 57.338393]ocfs2_xattr_trusted_set+0x28/0x30 [ 57.338665]? ocfs2_xattr_trusted_set+0x28/0x30 [ 57.338948]__vfs_removexattr+0x92/0xc0 [ 57.339182]__vfs_removexattr_locked+0xd5/0x190 [ 57.339456]? preempt_count_sub+0x50/0x80 [ 57.339705]vfs_removexattr+0x5f/0x100 [...] Reproducer uses faultinject facility to fail ocfs2_xa_remove() -> ocfs2_xa_value_truncate() with -ENOMEM. In this case the comment mentions that we can return 0 if ocfs2_xa_cleanup_value_truncate() is going to wipe the entry anyway. But the following 'rc' check is wrong and execution flow do 'ocfs2_xa_remove_entry(loc);' twice: * 1st: in ocfs2_xa_cleanup_value_truncate(); * 2nd: returning back to ocfs2_xa_remove() instead of going to 'out'. Fix this by skipping the 2nd removal of the same entry and making syzkaller repro happy.

Solution(s)

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

References

• https://attackerkb.com/topics/cve-2024-50265
• CVE - 2024-50265
• DSA-5818-1