linux-cve-announce - CVE-2024-40952: ocfs2: fix NULL pointer dereference in ocfs2_journal

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Message-ID: <2024071223-CVE-2024-40952-4ed1@gregkh>
Date: Fri, 12 Jul 2024 14:32:28 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2024-40952: ocfs2: fix NULL pointer dereference in ocfs2_journal_dirty()

Description
===========

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.

The Linux kernel CVE team has assigned CVE-2024-40952 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.6 with commit 8887b94d9322 and fixed in 6.6.36 with commit 0550ad87711f
	Issue introduced in 6.6 with commit 8887b94d9322 and fixed in 6.9.7 with commit 72663d3e0909
	Issue introduced in 6.6 with commit 8887b94d9322 and fixed in 6.10-rc5 with commit 58f7e1e2c9e7

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-40952
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	fs/ocfs2/journal.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/0550ad87711f815b3d73e487ec58ca7d8f56edbc
	https://git.kernel.org/stable/c/72663d3e09091f431a0774227ca207c0358362dd
	https://git.kernel.org/stable/c/58f7e1e2c9e72c7974054c64c3abeac81c11f822