Message-ID: <2025102820-CVE-2025-40082-3f03@gregkh>
Date: Tue, 28 Oct 2025 12:48:59 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-40082: hfsplus: fix slab-out-of-bounds read in hfsplus_uni2asc()

From: Greg Kroah-Hartman <gregkh@...nel.org>

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

In the Linux kernel, the following vulnerability has been resolved:

hfsplus: fix slab-out-of-bounds read in hfsplus_uni2asc()

BUG: KASAN: slab-out-of-bounds in hfsplus_uni2asc+0xa71/0xb90 fs/hfsplus/unicode.c:186
Read of size 2 at addr ffff8880289ef218 by task syz.6.248/14290

CPU: 0 UID: 0 PID: 14290 Comm: syz.6.248 Not tainted 6.16.4 #1 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x5f0 mm/kasan/report.c:482
 kasan_report+0xca/0x100 mm/kasan/report.c:595
 hfsplus_uni2asc+0xa71/0xb90 fs/hfsplus/unicode.c:186
 hfsplus_listxattr+0x5b6/0xbd0 fs/hfsplus/xattr.c:738
 vfs_listxattr+0xbe/0x140 fs/xattr.c:493
 listxattr+0xee/0x190 fs/xattr.c:924
 filename_listxattr fs/xattr.c:958 [inline]
 path_listxattrat+0x143/0x360 fs/xattr.c:988
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcb/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe0e9fae16d
Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe0eae67f98 EFLAGS: 00000246 ORIG_RAX: 00000000000000c3
RAX: ffffffffffffffda RBX: 00007fe0ea205fa0 RCX: 00007fe0e9fae16d
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000000
RBP: 00007fe0ea0480f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe0ea206038 R14: 00007fe0ea205fa0 R15: 00007fe0eae48000
 </TASK>

Allocated by task 14290:
 kasan_save_stack+0x24/0x50 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4333 [inline]
 __kmalloc_noprof+0x219/0x540 mm/slub.c:4345
 kmalloc_noprof include/linux/slab.h:909 [inline]
 hfsplus_find_init+0x95/0x1f0 fs/hfsplus/bfind.c:21
 hfsplus_listxattr+0x331/0xbd0 fs/hfsplus/xattr.c:697
 vfs_listxattr+0xbe/0x140 fs/xattr.c:493
 listxattr+0xee/0x190 fs/xattr.c:924
 filename_listxattr fs/xattr.c:958 [inline]
 path_listxattrat+0x143/0x360 fs/xattr.c:988
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcb/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

When hfsplus_uni2asc is called from hfsplus_listxattr,
it actually passes in a struct hfsplus_attr_unistr*.
The size of the corresponding structure is different from that of hfsplus_unistr,
so the previous fix (94458781aee6) is insufficient.
The pointer on the unicode buffer is still going beyond the allocated memory.

This patch introduces two warpper functions hfsplus_uni2asc_xattr_str and
hfsplus_uni2asc_str to process two unicode buffers,
struct hfsplus_attr_unistr* and struct hfsplus_unistr* respectively.
When ustrlen value is bigger than the allocated memory size,
the ustrlen value is limited to an safe size.

The Linux kernel CVE team has assigned CVE-2025-40082 to this issue.


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

	Issue introduced in 6.17 with commit 94458781aee6045bd3d0ad4b80b02886b9e2219b and fixed in 6.17.3 with commit 857aefc70d4ae3b9bf1ae67434d27d0f79f80c9e
	Issue introduced in 6.17 with commit 94458781aee6045bd3d0ad4b80b02886b9e2219b and fixed in 6.18-rc1 with commit bea3e1d4467bcf292c8e54f080353d556d355e26
	Issue introduced in 5.4.297 with commit 73f7da507d787b489761a0fa280716f84fa32b2f
	Issue introduced in 5.10.241 with commit 76a4c6636a69d69409aa253b049b1be717a539c5
	Issue introduced in 5.15.190 with commit ccf0ad56a779e6704c0b27f555dec847f50c7557
	Issue introduced in 6.1.149 with commit 13604b1d7e7b125fb428cddbec6b8d92baad25d5
	Issue introduced in 6.6.103 with commit 291bb5d931c6f3cd7227b913302a17be21cf53b0
	Issue introduced in 6.12.43 with commit f7534cbfac0a9ffa4fa17cacc6e8b6446dae24ee
	Issue introduced in 6.15.11 with commit 6f93694bcbc2c2ab3e01cd8fba2f296faf34e6b9
	Issue introduced in 6.16.2 with commit 1ca69007e52a73bd8b84b988b61b319816ca8b01

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-2025-40082
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/dir.c
	fs/hfsplus/hfsplus_fs.h
	fs/hfsplus/unicode.c
	fs/hfsplus/xattr.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/857aefc70d4ae3b9bf1ae67434d27d0f79f80c9e
	https://git.kernel.org/stable/c/bea3e1d4467bcf292c8e54f080353d556d355e26

Powered by blists - more mailing lists