CVE-2026-46299: hfsplus: fix held lock freed on hfsplus_fill_super()

CVE-2026-46299: hfsplus: fix held lock freed on hfsplus_fill_super()

[Greg Kroah-Hartman]

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

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

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

hfsplus: fix held lock freed on hfsplus_fill_super()

hfsplus_fill_super() calls hfs_find_init() to initialize a search
structure, which acquires tree->tree_lock. If the subsequent call to
hfsplus_cat_build_key() fails, the function jumps to the out_put_root
error label without releasing the lock. The later cleanup path then
frees the tree data structure with the lock still held, triggering a
held lock freed warning.

Fix this by adding the missing hfs_find_exit(&fd) call before jumping
to the out_put_root error label. This ensures that tree->tree_lock is
properly released on the error path.

The bug was originally detected on v6.13-rc1 using an experimental
static analysis tool we are developing, and we have verified that the
issue persists in the latest mainline kernel. The tool is specifically
designed to detect memory management issues. It is currently under active
development and not yet publicly available.

We confirmed the bug by runtime testing under QEMU with x86_64 defconfig,
lockdep enabled, and CONFIG_HFSPLUS_FS=y. To trigger the error path, we
used GDB to dynamically shrink the max_unistr_len parameter to 1 before
hfsplus_asc2uni() is called. This forces hfsplus_asc2uni() to naturally
return -ENAMETOOLONG, which propagates to hfsplus_cat_build_key() and
exercises the faulty error path. The following warning was observed
during mount:

	=========================
	WARNING: held lock freed!
	7.0.0-rc3-00016-gb4f0dd314b39 #4 Not tainted
	-------------------------
	mount/174 is freeing memory ffff888103f92000-ffff888103f92fff, with a lock still held there!
	ffff888103f920b0 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x154/0x1e0
	2 locks held by mount/174:
	#0: ffff888103f960e0 (&type->s_umount_key#42/1){+.+.}-{4:4}, at: alloc_super.constprop.0+0x167/0xa40
	#1: ffff888103f920b0 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x154/0x1e0

	stack backtrace:
	CPU: 2 UID: 0 PID: 174 Comm: mount Not tainted 7.0.0-rc3-00016-gb4f0dd314b39 #4 PREEMPT(lazy)
	Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
	Call Trace:
	<TASK>
	dump_stack_lvl+0x82/0xd0
	debug_check_no_locks_freed+0x13a/0x180
	kfree+0x16b/0x510
	? hfsplus_fill_super+0xcb4/0x18a0
	hfsplus_fill_super+0xcb4/0x18a0
	? __pfx_hfsplus_fill_super+0x10/0x10
	? srso_return_thunk+0x5/0x5f
	? bdev_open+0x65f/0xc30
	? srso_return_thunk+0x5/0x5f
	? pointer+0x4ce/0xbf0
	? trace_contention_end+0x11c/0x150
	? __pfx_pointer+0x10/0x10
	? srso_return_thunk+0x5/0x5f
	? bdev_open+0x79b/0xc30
	? srso_return_thunk+0x5/0x5f
	? srso_return_thunk+0x5/0x5f
	? vsnprintf+0x6da/0x1270
	? srso_return_thunk+0x5/0x5f
	? __mutex_unlock_slowpath+0x157/0x740
	? __pfx_vsnprintf+0x10/0x10
	? srso_return_thunk+0x5/0x5f
	? srso_return_thunk+0x5/0x5f
	? mark_held_locks+0x49/0x80
	? srso_return_thunk+0x5/0x5f
	? srso_return_thunk+0x5/0x5f
	? irqentry_exit+0x17b/0x5e0
	? trace_irq_disable.constprop.0+0x116/0x150
	? __pfx_hfsplus_fill_super+0x10/0x10
	? __pfx_hfsplus_fill_super+0x10/0x10
	get_tree_bdev_flags+0x302/0x580
	? __pfx_get_tree_bdev_flags+0x10/0x10
	? vfs_parse_fs_qstr+0x129/0x1a0
	? __pfx_vfs_parse_fs_qstr+0x3/0x10
	vfs_get_tree+0x89/0x320
	fc_mount+0x10/0x1d0
	path_mount+0x5c5/0x21c0
	? __pfx_path_mount+0x10/0x10
	? trace_irq_enable.constprop.0+0x116/0x150
	? trace_irq_enable.constprop.0+0x116/0x150
	? srso_return_thunk+0x5/0x5f
	? srso_return_thunk+0x5/0x5f
	? kmem_cache_free+0x307/0x540
	? user_path_at+0x51/0x60
	? __x64_sys_mount+0x212/0x280
	? srso_return_thunk+0x5/0x5f
	__x64_sys_mount+0x212/0x280
	? __pfx___x64_sys_mount+0x10/0x10
	? srso_return_thunk+0x5/0x5f
	? trace_irq_enable.constprop.0+0x116/0x150
	? srso_return_thunk+0x5/0x5f
	do_syscall_64+0x111/0x680
	entry_SYSCALL_64_after_hwframe+0x77/0x7f
	RIP: 0033:0x7ffacad55eae
	Code: 48 8b 0d 85 1f 0f 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 49 89 ca b8 a5 00 00 8
	RSP: 002b:00007fff1ab55718 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
	RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ffacad55eae
	RDX: 000055740c64e5b0 RSI: 000055740c64e630 RDI: 000055740c651ab0
	RBP: 000055740c64e380 R08: 0000000000000000 R09: 0000000000000001
	R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
	R13: 000055740c64e5b0 R14: 000055740c651ab0 R15: 000055740c64e380
	</TASK>

After applying this patch, the warning no longer appears.

The Linux kernel CVE team has assigned CVE-2026-46299 to this issue.


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

	Issue introduced in 3.19 with commit 89ac9b4d3d1a049ae1054f99b1aed81092cd0a82 and fixed in 6.6.140 with commit 3ca80e3012c8be85b4f8d0d20eac8d3b17ff257e
	Issue introduced in 3.19 with commit 89ac9b4d3d1a049ae1054f99b1aed81092cd0a82 and fixed in 6.12.88 with commit 041acda6d9f96006703466449c10c9a69590c8b9
	Issue introduced in 3.19 with commit 89ac9b4d3d1a049ae1054f99b1aed81092cd0a82 and fixed in 6.18.30 with commit d309d3308de658d87c42d97e044c89a226327526
	Issue introduced in 3.19 with commit 89ac9b4d3d1a049ae1054f99b1aed81092cd0a82 and fixed in 7.0.7 with commit bfbcce6a7b0552a390620d9b2c4d2bcb1825cbdc
	Issue introduced in 3.19 with commit 89ac9b4d3d1a049ae1054f99b1aed81092cd0a82 and fixed in 7.1-rc1 with commit 90c500e4fd83fa33c09bc7ee23b6d9cc487ac733

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-2026-46299
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/super.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/3ca80e3012c8be85b4f8d0d20eac8d3b17ff257e
	https://git.kernel.org/stable/c/041acda6d9f96006703466449c10c9a69590c8b9
	https://git.kernel.org/stable/c/d309d3308de658d87c42d97e044c89a226327526
	https://git.kernel.org/stable/c/bfbcce6a7b0552a390620d9b2c4d2bcb1825cbdc
	https://git.kernel.org/stable/c/90c500e4fd83fa33c09bc7ee23b6d9cc487ac733