CVE-2024-40952

Medium

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix NULL pointer dereference in ocfs2_journal_dirty() bdev->bd_super has been removed and commit 8887b94d9322 change the usage from bdev->bd_super to b_assoc_map->host->i_sb. This introduces the following NULL pointer dereference in ocfs2_journal_dirty() since b_assoc_map is still not initialized. This can be easily reproduced by running xfstests generic/186, which simulate no more credits. [ 134.351592] BUG: kernel NULL pointer dereference, address: 0000000000000000 ... [ 134.355341] RIP: 0010:ocfs2_journal_dirty+0x14f/0x160 [ocfs2] ... [ 134.365071] Call Trace: [ 134.365312] <TASK> [ 134.365524] ? __die_body+0x1e/0x60 [ 134.365868] ? page_fault_oops+0x13d/0x4f0 [ 134.366265] ? __pfx_bit_wait_io+0x10/0x10 [ 134.366659] ? schedule+0x27/0xb0 [ 134.366981] ? exc_page_fault+0x6a/0x140 [ 134.367356] ? asm_exc_page_fault+0x26/0x30 [ 134.367762] ? ocfs2_journal_dirty+0x14f/0x160 [ocfs2] [ 134.368305] ? ocfs2_journal_dirty+0x13d/0x160 [ocfs2] [ 134.368837] ocfs2_create_new_meta_bhs.isra.51+0x139/0x2e0 [ocfs2] [ 134.369454] ocfs2_grow_tree+0x688/0x8a0 [ocfs2] [ 134.369927] ocfs2_split_and_insert.isra.67+0x35c/0x4a0 [ocfs2] [ 134.370521] ocfs2_split_extent+0x314/0x4d0 [ocfs2] [ 134.371019] ocfs2_change_extent_flag+0x174/0x410 [ocfs2] [ 134.371566] ocfs2_add_refcount_flag+0x3fa/0x630 [ocfs2] [ 134.372117] ocfs2_reflink_remap_extent+0x21b/0x4c0 [ocfs2] [ 134.372994] ? inode_update_timestamps+0x4a/0x120 [ 134.373692] ? __pfx_ocfs2_journal_access_di+0x10/0x10 [ocfs2] [ 134.374545] ? __pfx_ocfs2_journal_access_di+0x10/0x10 [ocfs2] [ 134.375393] ocfs2_reflink_remap_blocks+0xe4/0x4e0 [ocfs2] [ 134.376197] ocfs2_remap_file_range+0x1de/0x390 [ocfs2] [ 134.376971] ? security_file_permission+0x29/0x50 [ 134.377644] vfs_clone_file_range+0xfe/0x320 [ 134.378268] ioctl_file_clone+0x45/0xa0 [ 134.378853] do_vfs_ioctl+0x457/0x990 [ 134.379422] __x64_sys_ioctl+0x6e/0xd0 [ 134.379987] do_syscall_64+0x5d/0x170 [ 134.380550] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 134.381231] RIP: 0033:0x7fa4926397cb [ 134.381786] Code: 73 01 c3 48 8b 0d bd 56 38 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8d 56 38 00 f7 d8 64 89 01 48 [ 134.383930] RSP: 002b:00007ffc2b39f7b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 134.384854] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fa4926397cb [ 134.385734] RDX: 00007ffc2b39f7f0 RSI: 000000004020940d RDI: 0000000000000003 [ 134.386606] RBP: 0000000000000000 R08: 00111a82a4f015bb R09: 00007fa494221000 [ 134.387476] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 134.388342] R13: 0000000000f10000 R14: 0000558e844e2ac8 R15: 0000000000f10000 [ 134.389207] </TASK> Fix it by only aborting transaction and journal in ocfs2_journal_dirty() now, and leave ocfs2_abort() later when detecting an aborted handle, e.g. start next transaction. Also log the handle details in this case.

Package Linux Kernel
Published 2024-07-12
Last modified 2024-11-21
CVSS version 3.1
Patch available
Awaiting data

CVSS 3.1 score

5.5

out of 10
Medium
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness type

CWE-476

CVE-2024-40952 is a NULL Pointer Dereference vulnerability

What is NULL Pointer Dereference?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. Learn more on MITRE CWE

References

The following references provide additional information about CVE-2024-40952 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Frequently asked questions

  • What is CVE-2024-40952?

    CVE-2024-40952 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a NULL Pointer Dereference flaw (CWE-476) . CVE-2024-40952 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2024-40952?

    CVE-2024-40952 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2024-40952?

    No patch is currently available for CVE-2024-40952. Monitor the NIST NVD and your Linux distribution's security advisories for updates.

  • Is CVE-2024-40952 actively exploited?

    No — CVE-2024-40952 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is NULL Pointer Dereference (CWE-476)?

    The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. View CWE-476 on MITRE CWE →

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