CVE-2024-50265

ocfs2: remove entry once instead of null-ptr-dereference in ocfs2_xa_remove()

Published Nov 19, 2024 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Debian DLA Debian DLA DLA-4008-1 linux-6.1 security update
Debian DLA Debian DLA DLA-4075-1 linux security update
Debian DSA Debian DSA DSA-5818-1 linux security update
Ubuntu USN Ubuntu USN USN-7276-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7277-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7288-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7288-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7289-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7289-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7289-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7289-4 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7291-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7293-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7294-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7294-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7294-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7294-4 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7295-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7305-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7308-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7310-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7331-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7388-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7389-1 Linux kernel (NVIDIA Tegra) vulnerabilities
Ubuntu USN Ubuntu USN USN-7390-1 Linux kernel (Xilinx ZynqMP) vulnerabilities
Ubuntu USN Ubuntu USN USN-7393-1 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7401-1 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7413-1 Linux kernel (IoT) vulnerabilities
Ubuntu USN Ubuntu USN USN-7428-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7428-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7429-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7429-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7449-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7449-2 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-7450-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7451-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7452-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7453-1 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7458-1 Linux kernel (IBM) vulnerabilities
Ubuntu USN Ubuntu USN USN-7468-1 Linux kernel (Azure, N-Series) vulnerabilities
Ubuntu USN Ubuntu USN USN-7523-1 Linux kernel (Raspberry Pi Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7524-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-7539-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-7540-1 Linux kernel (Raspberry Pi) vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Weaknesses CWE-476
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.12:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.12:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.12:rc6:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Type Values Removed Values Added
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.
Title ocfs2: remove entry once instead of null-ptr-dereference in ocfs2_xa_remove()
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
May 11, 2026, 8:48 PM
Reserved
Oct 21, 2024, 7:36 PM
Status
Modified
Published
Nov 19, 2024, 2:16 AM
Modified
Jun 17, 2026, 8:04 AM
Severity
Low
Public date
Nov 19, 2024, 12:00 AM