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Message-ID: <2025121635-CVE-2025-40349-82c6@gregkh>
Date: Tue, 16 Dec 2025 14:30:36 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-40349: hfs: validate record offset in hfsplus_bmap_alloc
From: Greg Kroah-Hartman <gregkh@...nel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
hfs: validate record offset in hfsplus_bmap_alloc
hfsplus_bmap_alloc can trigger a crash if a
record offset or length is larger than node_size
[ 15.264282] BUG: KASAN: slab-out-of-bounds in hfsplus_bmap_alloc+0x887/0x8b0
[ 15.265192] Read of size 8 at addr ffff8881085ca188 by task test/183
[ 15.265949]
[ 15.266163] CPU: 0 UID: 0 PID: 183 Comm: test Not tainted 6.17.0-rc2-gc17b750b3ad9 #14 PREEMPT(voluntary)
[ 15.266165] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 15.266167] Call Trace:
[ 15.266168] <TASK>
[ 15.266169] dump_stack_lvl+0x53/0x70
[ 15.266173] print_report+0xd0/0x660
[ 15.266181] kasan_report+0xce/0x100
[ 15.266185] hfsplus_bmap_alloc+0x887/0x8b0
[ 15.266208] hfs_btree_inc_height.isra.0+0xd5/0x7c0
[ 15.266217] hfsplus_brec_insert+0x870/0xb00
[ 15.266222] __hfsplus_ext_write_extent+0x428/0x570
[ 15.266225] __hfsplus_ext_cache_extent+0x5e/0x910
[ 15.266227] hfsplus_ext_read_extent+0x1b2/0x200
[ 15.266233] hfsplus_file_extend+0x5a7/0x1000
[ 15.266237] hfsplus_get_block+0x12b/0x8c0
[ 15.266238] __block_write_begin_int+0x36b/0x12c0
[ 15.266251] block_write_begin+0x77/0x110
[ 15.266252] cont_write_begin+0x428/0x720
[ 15.266259] hfsplus_write_begin+0x51/0x100
[ 15.266262] cont_write_begin+0x272/0x720
[ 15.266270] hfsplus_write_begin+0x51/0x100
[ 15.266274] generic_perform_write+0x321/0x750
[ 15.266285] generic_file_write_iter+0xc3/0x310
[ 15.266289] __kernel_write_iter+0x2fd/0x800
[ 15.266296] dump_user_range+0x2ea/0x910
[ 15.266301] elf_core_dump+0x2a94/0x2ed0
[ 15.266320] vfs_coredump+0x1d85/0x45e0
[ 15.266349] get_signal+0x12e3/0x1990
[ 15.266357] arch_do_signal_or_restart+0x89/0x580
[ 15.266362] irqentry_exit_to_user_mode+0xab/0x110
[ 15.266364] asm_exc_page_fault+0x26/0x30
[ 15.266366] RIP: 0033:0x41bd35
[ 15.266367] Code: bc d1 f3 0f 7f 27 f3 0f 7f 6f 10 f3 0f 7f 77 20 f3 0f 7f 7f 30 49 83 c0 0f 49 29 d0 48 8d 7c 17 31 e9 9f 0b 00 00 66 0f ef c0 <f3> 0f 6f 0e f3 0f 6f 56 10 66 0f 74 c1 66 0f d7 d0 49 83 f8f
[ 15.266369] RSP: 002b:00007ffc9e62d078 EFLAGS: 00010283
[ 15.266371] RAX: 00007ffc9e62d100 RBX: 0000000000000000 RCX: 0000000000000000
[ 15.266372] RDX: 00000000000000e0 RSI: 0000000000000000 RDI: 00007ffc9e62d100
[ 15.266373] RBP: 0000400000000040 R08: 00000000000000e0 R09: 0000000000000000
[ 15.266374] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[ 15.266375] R13: 0000000000000000 R14: 0000000000000000 R15: 0000400000000000
[ 15.266376] </TASK>
When calling hfsplus_bmap_alloc to allocate a free node, this function
first retrieves the bitmap from header node and map node using node->page
together with the offset and length from hfs_brec_lenoff
```
len = hfs_brec_lenoff(node, 2, &off16);
off = off16;
off += node->page_offset;
pagep = node->page + (off >> PAGE_SHIFT);
data = kmap_local_page(*pagep);
```
However, if the retrieved offset or length is invalid(i.e. exceeds
node_size), the code may end up accessing pages outside the allocated
range for this node.
This patch adds proper validation of both offset and length before use,
preventing out-of-bounds page access. Move is_bnode_offset_valid and
check_and_correct_requested_length to hfsplus_fs.h, as they may be
required by other functions.
The Linux kernel CVE team has assigned CVE-2025-40349 to this issue.
Affected and fixed versions
===========================
Fixed in 5.4.301 with commit f7d9f600c7c3ff5dab36181a388af55f2c95604c
Fixed in 5.10.246 with commit 40dfe7a4215a1f20842561ffaf5a6f83a987e75b
Fixed in 5.15.196 with commit 418e48cab99c52c1760636a4dbe464bf6db2018b
Fixed in 6.1.158 with commit 0058d20d76182861dbdd8fd6e2dd8d18d6d3becf
Fixed in 6.6.115 with commit 4f40a2b3969daf10dca4dea6f6dd0e813f79b227
Fixed in 6.12.56 with commit 17ed51cfce6c62cffb97059ef392ad2e0245806e
Fixed in 6.17.6 with commit 068a46df3e6acc68fb9db0a6313ab379a11ecd6f
Fixed in 6.18 with commit 738d5a51864ed8d7a68600b8c0c63fe6fe5c4f20
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-2025-40349
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/bnode.c
fs/hfsplus/btree.c
fs/hfsplus/hfsplus_fs.h
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/f7d9f600c7c3ff5dab36181a388af55f2c95604c
https://git.kernel.org/stable/c/40dfe7a4215a1f20842561ffaf5a6f83a987e75b
https://git.kernel.org/stable/c/418e48cab99c52c1760636a4dbe464bf6db2018b
https://git.kernel.org/stable/c/0058d20d76182861dbdd8fd6e2dd8d18d6d3becf
https://git.kernel.org/stable/c/4f40a2b3969daf10dca4dea6f6dd0e813f79b227
https://git.kernel.org/stable/c/17ed51cfce6c62cffb97059ef392ad2e0245806e
https://git.kernel.org/stable/c/068a46df3e6acc68fb9db0a6313ab379a11ecd6f
https://git.kernel.org/stable/c/738d5a51864ed8d7a68600b8c0c63fe6fe5c4f20
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