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Message-ID: <2025120404-CVE-2025-40244-941b@gregkh>
Date: Thu, 4 Dec 2025 16:32:19 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-40244: hfsplus: fix KMSAN uninit-value issue in __hfsplus_ext_cache_extent()
From: Greg Kroah-Hartman <gregkh@...nel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
hfsplus: fix KMSAN uninit-value issue in __hfsplus_ext_cache_extent()
The syzbot reported issue in __hfsplus_ext_cache_extent():
[ 70.194323][ T9350] BUG: KMSAN: uninit-value in __hfsplus_ext_cache_extent+0x7d0/0x990
[ 70.195022][ T9350] __hfsplus_ext_cache_extent+0x7d0/0x990
[ 70.195530][ T9350] hfsplus_file_extend+0x74f/0x1cf0
[ 70.195998][ T9350] hfsplus_get_block+0xe16/0x17b0
[ 70.196458][ T9350] __block_write_begin_int+0x962/0x2ce0
[ 70.196959][ T9350] cont_write_begin+0x1000/0x1950
[ 70.197416][ T9350] hfsplus_write_begin+0x85/0x130
[ 70.197873][ T9350] generic_perform_write+0x3e8/0x1060
[ 70.198374][ T9350] __generic_file_write_iter+0x215/0x460
[ 70.198892][ T9350] generic_file_write_iter+0x109/0x5e0
[ 70.199393][ T9350] vfs_write+0xb0f/0x14e0
[ 70.199771][ T9350] ksys_write+0x23e/0x490
[ 70.200149][ T9350] __x64_sys_write+0x97/0xf0
[ 70.200570][ T9350] x64_sys_call+0x3015/0x3cf0
[ 70.201065][ T9350] do_syscall_64+0xd9/0x1d0
[ 70.201506][ T9350] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 70.202054][ T9350]
[ 70.202279][ T9350] Uninit was created at:
[ 70.202693][ T9350] __kmalloc_noprof+0x621/0xf80
[ 70.203149][ T9350] hfsplus_find_init+0x8d/0x1d0
[ 70.203602][ T9350] hfsplus_file_extend+0x6ca/0x1cf0
[ 70.204087][ T9350] hfsplus_get_block+0xe16/0x17b0
[ 70.204561][ T9350] __block_write_begin_int+0x962/0x2ce0
[ 70.205074][ T9350] cont_write_begin+0x1000/0x1950
[ 70.205547][ T9350] hfsplus_write_begin+0x85/0x130
[ 70.206017][ T9350] generic_perform_write+0x3e8/0x1060
[ 70.206519][ T9350] __generic_file_write_iter+0x215/0x460
[ 70.207042][ T9350] generic_file_write_iter+0x109/0x5e0
[ 70.207552][ T9350] vfs_write+0xb0f/0x14e0
[ 70.207961][ T9350] ksys_write+0x23e/0x490
[ 70.208375][ T9350] __x64_sys_write+0x97/0xf0
[ 70.208810][ T9350] x64_sys_call+0x3015/0x3cf0
[ 70.209255][ T9350] do_syscall_64+0xd9/0x1d0
[ 70.209680][ T9350] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 70.210230][ T9350]
[ 70.210454][ T9350] CPU: 2 UID: 0 PID: 9350 Comm: repro Not tainted 6.12.0-rc5 #5
[ 70.211174][ T9350] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 70.212115][ T9350] =====================================================
[ 70.212734][ T9350] Disabling lock debugging due to kernel taint
[ 70.213284][ T9350] Kernel panic - not syncing: kmsan.panic set ...
[ 70.213858][ T9350] CPU: 2 UID: 0 PID: 9350 Comm: repro Tainted: G B 6.12.0-rc5 #5
[ 70.214679][ T9350] Tainted: [B]=BAD_PAGE
[ 70.215057][ T9350] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 70.215999][ T9350] Call Trace:
[ 70.216309][ T9350] <TASK>
[ 70.216585][ T9350] dump_stack_lvl+0x1fd/0x2b0
[ 70.217025][ T9350] dump_stack+0x1e/0x30
[ 70.217421][ T9350] panic+0x502/0xca0
[ 70.217803][ T9350] ? kmsan_get_metadata+0x13e/0x1c0
[ 70.218294][ Message fromT sy9350] kmsan_report+0x296/slogd@...kaller 0x2aat Aug 18 22:11:058 ...
kernel
:[ 70.213284][ T9350] Kernel panic - not syncing: kmsan.panic [ 70.220179][ T9350] ? kmsan_get_metadata+0x13e/0x1c0
set ...
[ 70.221254][ T9350] ? __msan_warning+0x96/0x120
[ 70.222066][ T9350] ? __hfsplus_ext_cache_extent+0x7d0/0x990
[ 70.223023][ T9350] ? hfsplus_file_extend+0x74f/0x1cf0
[ 70.224120][ T9350] ? hfsplus_get_block+0xe16/0x17b0
[ 70.224946][ T9350] ? __block_write_begin_int+0x962/0x2ce0
[ 70.225756][ T9350] ? cont_write_begin+0x1000/0x1950
[ 70.226337][ T9350] ? hfsplus_write_begin+0x85/0x130
[ 70.226852][ T9350] ? generic_perform_write+0x3e8/0x1060
[ 70.227405][ T9350] ? __generic_file_write_iter+0x215/0x460
[ 70.227979][ T9350] ? generic_file_write_iter+0x109/0x5e0
[ 70.228540][ T9350] ? vfs_write+0xb0f/0x14e0
[ 70.228997][ T9350] ? ksys_write+0x23e/0x490
[ 70.229458][ T9350] ? __x64_sys_write+0x97/0xf0
[ 70.229939][ T9350] ? x64_sys_call+0x3015/0x3cf0
[ 70.230432][ T9350] ? do_syscall_64+0xd9/0x1d0
[ 70.230941][ T9350] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 70.231926][ T9350] ? kmsan_get_metadata+0x13e/0x1c0
[ 70.232738][ T9350] ? kmsan_internal_set_shadow_origin+0x77/0x110
[ 70.233711][ T9350] ? kmsan_get_metadata+0x13e/0x1c0
[ 70.234516][ T9350] ? kmsan_get_shadow_origin_ptr+0x4a/0xb0
[ 70.235398][ T9350] ? __msan_metadata_ptr_for_load_4+0x24/0x40
[ 70.236323][ T9350] ? hfsplus_brec_find+0x218/0x9f0
[ 70.237090][ T9350] ? __pfx_hfs_find_rec_by_key+0x10/0x10
[ 70.237938][ T9350] ? __msan_instrument_asm_store+0xbf/0xf0
[ 70.238827][ T9350] ? __msan_metadata_ptr_for_store_4+0x27/0x40
[ 70.239772][ T9350] ? __hfsplus_ext_write_extent+0x536/0x620
[ 70.240666][ T9350] ? kmsan_get_metadata+0x13e/0x1c0
[ 70.241175][ T9350] __msan_warning+0x96/0x120
[ 70.241645][ T9350] __hfsplus_ext_cache_extent+0x7d0/0x990
[ 70.242223][ T9350] hfsplus_file_extend+0x74f/0x1cf0
[ 70.242748][ T9350] hfsplus_get_block+0xe16/0x17b0
[ 70.243255][ T9350] ? kmsan_internal_set_shadow_origin+0x77/0x110
[ 70.243878][ T9350] ? kmsan_get_metadata+0x13e/0x1c0
[ 70.244400][ T9350] ? kmsan_get_shadow_origin_ptr+0x4a/0xb0
[ 70.244967][ T9350] __block_write_begin_int+0x962/0x2ce0
[ 70.245531][ T9350] ? __pfx_hfsplus_get_block+0x10/0x10
[ 70.246079][ T9350] cont_write_begin+0x1000/0x1950
[ 70.246598][ T9350] hfsplus_write_begin+0x85/0x130
[ 70.247105][ T9350] ? __pfx_hfsplus_get_block+0x10/0x10
[ 70.247650][ T9350] ? __pfx_hfsplus_write_begin+0x10/0x10
[ 70.248211][ T9350] generic_perform_write+0x3e8/0x1060
[ 70.248752][ T9350] __generic_file_write_iter+0x215/0x460
[ 70.249314][ T9350] generic_file_write_iter+0x109/0x5e0
[ 70.249856][ T9350] ? kmsan_internal_set_shadow_origin+0x77/0x110
[ 70.250487][ T9350] vfs_write+0xb0f/0x14e0
[ 70.250930][ T9350] ? __pfx_generic_file_write_iter+0x10/0x10
[ 70.251530][ T9350] ksys_write+0x23e/0x490
[ 70.251974][ T9350] __x64_sys_write+0x97/0xf0
[ 70.252450][ T9350] x64_sys_call+0x3015/0x3cf0
[ 70.252924][ T9350] do_syscall_64+0xd9/0x1d0
[ 70.253384][ T9350] ? irqentry_exit+0x16/0x60
[ 70.253844][ T9350] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 70.254430][ T9350] RIP: 0033:0x7f7a92adffc9
[ 70.254873][ T9350] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 48
[ 70.256674][ T9350] RSP: 002b:00007fff0bca3188 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
[ 70.257485][ T9350] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7a92adffc9
[ 70.258246][ T9350] RDX: 000000000208e24b RSI: 0000000020000100 RDI: 0000000000000004
[ 70.258998][ T9350] RBP: 00007fff0bca31a0 R08: 00007fff0bca31a0 R09: 00007fff0bca31a0
[ 70.259769][ T9350] R10: 0000000000000000 R11: 0000000000000202 R12: 000055e0d75f8250
[ 70.260520][ T9350] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 70.261286][ T9350] </TASK>
[ 70.262026][ T9350] Kernel Offset: disabled
(gdb) l *__hfsplus_ext_cache_extent+0x7d0
0xffffffff8318aef0 is in __hfsplus_ext_cache_extent (fs/hfsplus/extents.c:168).
163 fd->key->ext.cnid = 0;
164 res = hfs_brec_find(fd, hfs_find_rec_by_key);
165 if (res && res != -ENOENT)
166 return res;
167 if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
168 fd->key->ext.fork_type != fd->search_key->ext.fork_type)
169 return -ENOENT;
170 if (fd->entrylength != sizeof(hfsplus_extent_rec))
171 return -EIO;
172 hfs_bnode_read(fd->bnode, extent, fd->entryoffset,
The __hfsplus_ext_cache_extent() calls __hfsplus_ext_read_extent():
res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
block, HFSPLUS_IS_RSRC(inode) ?
HFSPLUS_TYPE_RSRC :
HFSPLUS_TYPE_DATA);
And if inode->i_ino could be equal to zero or any non-available CNID,
then hfs_brec_find() could not find the record in the tree. As a result,
fd->key could be compared with fd->search_key. But hfsplus_find_init()
uses kmalloc() for fd->key and fd->search_key allocation:
int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
{
<skipped>
ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
if (!ptr)
return -ENOMEM;
fd->search_key = ptr;
fd->key = ptr + tree->max_key_len + 2;
<skipped>
}
Finally, fd->key is still not initialized if hfs_brec_find()
has found nothing.
This patch changes kmalloc() on kzalloc() in hfs_find_init()
and intializes fd->record, fd->keyoffset, fd->keylength,
fd->entryoffset, fd->entrylength for the case if hfs_brec_find()
has been found nothing in the b-tree node.
The Linux kernel CVE team has assigned CVE-2025-40244 to this issue.
Affected and fixed versions
===========================
Fixed in 5.4.301 with commit c1ec90bed504640a42bb20a5f413be39cd17ad71
Fixed in 5.10.246 with commit b8a72692aa42b7dcd179a96b90bc2763ac74576a
Fixed in 5.15.196 with commit c135b8dca65526aa5b8814e9954e0ae317d9c598
Fixed in 6.1.158 with commit d7e313039a8f3a6ee072dc5ff4643234d2d735cf
Fixed in 6.6.115 with commit a5bfb13b4f406aef1a450f99d22d3e48df01528c
Fixed in 6.12.56 with commit 99202d94909d323a30d154ab0261c0a07166daec
Fixed in 6.17.6 with commit 14c673a2f3ecf650b694a52a88688f1d71849899
Fixed in 6.18 with commit 4840ceadef4290c56cc422f0fc697655f3cbf070
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-2025-40244
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/hfsplus/bfind.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/c1ec90bed504640a42bb20a5f413be39cd17ad71
https://git.kernel.org/stable/c/b8a72692aa42b7dcd179a96b90bc2763ac74576a
https://git.kernel.org/stable/c/c135b8dca65526aa5b8814e9954e0ae317d9c598
https://git.kernel.org/stable/c/d7e313039a8f3a6ee072dc5ff4643234d2d735cf
https://git.kernel.org/stable/c/a5bfb13b4f406aef1a450f99d22d3e48df01528c
https://git.kernel.org/stable/c/99202d94909d323a30d154ab0261c0a07166daec
https://git.kernel.org/stable/c/14c673a2f3ecf650b694a52a88688f1d71849899
https://git.kernel.org/stable/c/4840ceadef4290c56cc422f0fc697655f3cbf070
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