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Seunghun Han 0a119fdaed ACPICA: fix acpi parse and parseext cache leaks [ Upstream commit `bed18f0bdc` ] ACPICA commit 8829e70e1360c81e7a5a901b5d4f48330e021ea5 I'm Seunghun Han, and I work for National Security Research Institute of South Korea. I have been doing a research on ACPI and found an ACPI cache leak in ACPI early abort cases. Boot log of ACPI cache leak is as follows: [ 0.352414] ACPI: Added _OSI(Module Device) [ 0.353182] ACPI: Added _OSI(Processor Device) [ 0.353182] ACPI: Added _OSI(3.0 _SCP Extensions) [ 0.353182] ACPI: Added _OSI(Processor Aggregator Device) [ 0.356028] ACPI: Unable to start the ACPI Interpreter [ 0.356799] ACPI Error: Could not remove SCI handler (20170303/evmisc-281) [ 0.360215] kmem_cache_destroy Acpi-State: Slab cache still has objects [ 0.360648] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 4.12.0-rc4-next-20170608+ #10 [ 0.361273] Hardware name: innotek gmb_h virtual_box/virtual_box, BIOS virtual_box 12/01/2006 [ 0.361873] Call Trace: [ 0.362243] ? dump_stack+0x5c/0x81 [ 0.362591] ? kmem_cache_destroy+0x1aa/0x1c0 [ 0.362944] ? acpi_sleep_proc_init+0x27/0x27 [ 0.363296] ? acpi_os_delete_cache+0xa/0x10 [ 0.363646] ? acpi_ut_delete_caches+0x6d/0x7b [ 0.364000] ? acpi_terminate+0xa/0x14 [ 0.364000] ? acpi_init+0x2af/0x34f [ 0.364000] ? __class_create+0x4c/0x80 [ 0.364000] ? video_setup+0x7f/0x7f [ 0.364000] ? acpi_sleep_proc_init+0x27/0x27 [ 0.364000] ? do_one_initcall+0x4e/0x1a0 [ 0.364000] ? kernel_init_freeable+0x189/0x20a [ 0.364000] ? rest_init+0xc0/0xc0 [ 0.364000] ? kernel_init+0xa/0x100 [ 0.364000] ? ret_from_fork+0x25/0x30 I analyzed this memory leak in detail. I found that “Acpi-State” cache and “Acpi-Parse” cache were merged because the size of cache objects was same slab cache size. I finally found “Acpi-Parse” cache and “Acpi-parse_ext” cache were leaked using SLAB_NEVER_MERGE flag in kmem_cache_create() function. Real ACPI cache leak point is as follows: [ 0.360101] ACPI: Added _OSI(Module Device) [ 0.360101] ACPI: Added _OSI(Processor Device) [ 0.360101] ACPI: Added _OSI(3.0 _SCP Extensions) [ 0.361043] ACPI: Added _OSI(Processor Aggregator Device) [ 0.364016] ACPI: Unable to start the ACPI Interpreter [ 0.365061] ACPI Error: Could not remove SCI handler (20170303/evmisc-281) [ 0.368174] kmem_cache_destroy Acpi-Parse: Slab cache still has objects [ 0.369332] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G W 4.12.0-rc4-next-20170608+ #8 [ 0.371256] Hardware name: innotek gmb_h virtual_box/virtual_box, BIOS virtual_box 12/01/2006 [ 0.372000] Call Trace: [ 0.372000] ? dump_stack+0x5c/0x81 [ 0.372000] ? kmem_cache_destroy+0x1aa/0x1c0 [ 0.372000] ? acpi_sleep_proc_init+0x27/0x27 [ 0.372000] ? acpi_os_delete_cache+0xa/0x10 [ 0.372000] ? acpi_ut_delete_caches+0x56/0x7b [ 0.372000] ? acpi_terminate+0xa/0x14 [ 0.372000] ? acpi_init+0x2af/0x34f [ 0.372000] ? __class_create+0x4c/0x80 [ 0.372000] ? video_setup+0x7f/0x7f [ 0.372000] ? acpi_sleep_proc_init+0x27/0x27 [ 0.372000] ? do_one_initcall+0x4e/0x1a0 [ 0.372000] ? kernel_init_freeable+0x189/0x20a [ 0.372000] ? rest_init+0xc0/0xc0 [ 0.372000] ? kernel_init+0xa/0x100 [ 0.372000] ? ret_from_fork+0x25/0x30 [ 0.388039] kmem_cache_destroy Acpi-parse_ext: Slab cache still has objects [ 0.389063] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G W 4.12.0-rc4-next-20170608+ #8 [ 0.390557] Hardware name: innotek gmb_h virtual_box/virtual_box, BIOS virtual_box 12/01/2006 [ 0.392000] Call Trace: [ 0.392000] ? dump_stack+0x5c/0x81 [ 0.392000] ? kmem_cache_destroy+0x1aa/0x1c0 [ 0.392000] ? acpi_sleep_proc_init+0x27/0x27 [ 0.392000] ? acpi_os_delete_cache+0xa/0x10 [ 0.392000] ? acpi_ut_delete_caches+0x6d/0x7b [ 0.392000] ? acpi_terminate+0xa/0x14 [ 0.392000] ? acpi_init+0x2af/0x34f [ 0.392000] ? __class_create+0x4c/0x80 [ 0.392000] ? video_setup+0x7f/0x7f [ 0.392000] ? acpi_sleep_proc_init+0x27/0x27 [ 0.392000] ? do_one_initcall+0x4e/0x1a0 [ 0.392000] ? kernel_init_freeable+0x189/0x20a [ 0.392000] ? rest_init+0xc0/0xc0 [ 0.392000] ? kernel_init+0xa/0x100 [ 0.392000] ? ret_from_fork+0x25/0x30 When early abort is occurred due to invalid ACPI information, Linux kernel terminates ACPI by calling acpi_terminate() function. The function calls acpi_ut_delete_caches() function to delete local caches (acpi_gbl_namespace_ cache, state_cache, operand_cache, ps_node_cache, ps_node_ext_cache). But the deletion codes in acpi_ut_delete_caches() function only delete slab caches using kmem_cache_destroy() function, therefore the cache objects should be flushed before acpi_ut_delete_caches() function. "Acpi-Parse" cache and "Acpi-ParseExt" cache are used in an AML parse function, acpi_ps_parse_loop(). The function should complete all ops using acpi_ps_complete_final_op() when an error occurs due to invalid AML codes. However, the current implementation of acpi_ps_complete_final_op() does not complete all ops when it meets some errors and this cause cache leak. This cache leak has a security threat because an old kernel (<= 4.9) shows memory locations of kernel functions in stack dump. Some malicious users could use this information to neutralize kernel ASLR. To fix ACPI cache leak for enhancing security, I made a patch to complete all ops unconditionally for acpi_ps_complete_final_op() function. I hope that this patch improves the security of Linux kernel. Thank you. Link: `8829e70e` Signed-off-by: Seunghun Han <kkamagui@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://patch.msgid.link/2363774.ElGaqSPkdT@rjwysocki.net Signed-off-by: Sasha Levin <sashal@kernel.org>		History 2025-06-27 11:07:32 +01:00
arch	mips: Add -std= flag specified in KBUILD_CFLAGS to vdso CFLAGS	2025-06-27 11:07:30 +01:00
block	scsi: sd_zbc: block: Respect bio vector limits for REPORT ZONES buffer	2025-05-22 14:10:06 +02:00
certs	sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3	2025-04-25 10:44:04 +02:00
crypto	crypto: xts - Only add ecb if it is not already there	2025-06-27 11:07:06 +01:00
Documentation	xfs: fix the contact address for the sysfs ABI documentation	2025-06-27 11:07:19 +01:00
drivers	ACPICA: fix acpi parse and parseext cache leaks	2025-06-27 11:07:32 +01:00
fs	cifs: reset connections for all channels when reconnect requested	2025-06-27 11:07:31 +01:00
include	ACPICA: Avoid sequence overread in call to strncmp()	2025-06-27 11:07:32 +01:00
init	sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP	2025-05-02 07:47:04 +02:00
io_uring	io_uring: account drain memory to cgroup	2025-06-27 11:07:26 +01:00
ipc	ipc: fix to protect IPCS lookups using RCU	2025-06-27 11:07:30 +01:00
kernel	clocksource: Fix the CPUs' choice in the watchdog per CPU verification	2025-06-27 11:07:31 +01:00
lib	crypto: lzo - Fix compression buffer overrun	2025-06-04 14:40:08 +02:00
LICENSES	LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers	2021-12-16 14:33:10 +01:00
mm	mm: fix ratelimit_pages update error in dirty_ratio_handler()	2025-06-27 11:07:30 +01:00
net	NFC: nci: uart: Set tty->disc_data only in success path	2025-06-27 11:07:29 +01:00
rust	scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`	2025-03-28 21:58:57 +01:00
samples	samples/bpf: Fix compilation failure for samples/bpf on LoongArch Fedora	2025-06-04 14:40:02 +02:00
scripts	kbuild: Add KBUILD_CPPFLAGS to as-option invocation	2025-06-27 11:07:24 +01:00
security	smack: recognize ipv4 CIPSO w/o categories	2025-06-04 14:40:14 +02:00
sound	ASoC: tas2770: Power cycle amp on ISENSE/VSENSE change	2025-06-27 11:07:32 +01:00
tools	tools/resolve_btfids: Fix build when cross compiling kernel with clang.	2025-06-27 11:07:24 +01:00
usr	kbuild: hdrcheck: fix cross build with clang	2025-06-27 11:07:25 +01:00
virt	KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin()	2024-06-27 13:46:21 +02:00
.clang-format	inet: ping: use hlist_nulls rcu iterator during lookup	2022-12-01 12:42:46 +01:00
.cocciconfig	scripts: add Linux .cocciconfig for coccinelle	2016-07-22 12:13:39 +02:00
.get_maintainer.ignore	get_maintainer: add Alan to .get_maintainer.ignore	2022-08-20 15:17:44 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	Remove *.orig pattern from .gitignore	2024-10-17 15:21:15 +02:00
.mailmap	9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address	2022-12-10 17:10:52 -08:00
.rustfmt.toml	rust: add `.rustfmt.toml`	2022-09-28 09:02:20 +02:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: Remove Michal Marek from Kbuild maintainers	2022-11-16 14:53:00 +09:00
Kbuild	Kbuild updates for v6.1	2022-10-10 12:00:45 -07:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	sign-file,extract-cert: move common SSL helper functions to a header	2025-04-25 10:44:04 +02:00
Makefile	kbuild: userprogs: fix bitsize and target detection on clang	2025-06-27 11:07:25 +01:00
README	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.