Messages in this thread | | | Date | Mon, 7 Nov 2022 17:30:36 +0800 | Subject | Re: [PATCH] ACPICA: Fix use-after-free in acpi_ps_parse_aml() | From | Chen Zhongjin <> |
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Hi,
On 2022/11/6 3:00, Rafael J. Wysocki wrote: > On Fri, Oct 28, 2022 at 5:46 PM Rafael J. Wysocki <rafael@kernel.org> wrote: >> On Wed, Oct 19, 2022 at 9:38 AM Chen Zhongjin <chenzhongjin@huawei.com> wrote: >>> KASAN reports a use-after-free problem and causes kernel panic >>> triggered by: modprobe acpiphp_ibm >>> >>> BUG: KASAN: >>> use-after-free in acpi_ds_dump_method_stack (drivers/acpi/acpica/dsdebug.c:145) >>> Read of size 8 at addr ffff888002f843f0 by task modprobe/519 >>> >>> CPU: 2 PID: 519 Comm: modprobe Not tainted 6.0.0+ >>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) >>> Call Trace: >>> <TASK> >>> acpi_ds_dump_method_stack (drivers/acpi/acpica/dsdebug.c:145) >>> acpi_ds_method_error (drivers/acpi/acpica/dsmethod.c:232) >>> acpi_ps_parse_aml (drivers/acpi/acpica/psparse.c:607) >>> ... >>> </TASK> >>> >>> Allocated by task 519: >>> ... >>> __kasan_kmalloc (mm/kasan/common.c:526) >>> acpi_ds_create_walk_state (drivers/acpi/acpica/dswstate.c:519) >>> acpi_ds_call_control_method (drivers/acpi/acpica/dsmethod.c:498) >>> acpi_ps_parse_aml (drivers/acpi/acpica/psparse.c:607) >>> ... >>> >>> Freed by task 519: >>> ... >>> __kmem_cache_free+0xb6/0x3c0 >>> acpi_ds_delete_walk_state (drivers/acpi/acpica/dswstate.c:722) >>> acpi_ds_call_control_method (drivers/acpi/acpica/dsmethod.c:586) >>> acpi_ps_parse_aml (drivers/acpi/acpica/psparse.c:607) >>> ... >>> ---[ end Kernel panic - not syncing: Fatal exception ]--- >>> >>> In the error path in acpi_ps_parse_aml(): >>> >>> acpi_ds_call_control_method() >>> acpi_ds_create_walk_state() >>> acpi_ds_push_walk_state() >>> # thread->walk_state_list = walk_state >>> >>> acpi_ds_init_aml_walk # *fail* >>> goto cleanup: >>> acpi_ds_delete_walk_state() # ACPI_FREE(walk_state) >>> >>> acpi_ds_method_error() >>> acpi_ds_dump_method_stack() >>> # using freed thread->walk_state_list >>> >>> Briefly, the walk_state is pushed to thread, and freed without being poped. >>> Then it is used in acpi_ds_dump_method_stack() and causes use-after-free. >>> >>> Add acpi_ds_pop_walk_state(thread) to the error path to fix the problem. >>> >>> Fixes: 0bac4295526c ("ACPICA: Dispatcher: Move stack traversal code to dispatcher") >>> >>> Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com> >> This should be submitted to the upstream project on GitHub, but it >> looks bad enough, so I'll take care of this. >> >> Applied as 6.1-rc material, thanks! >> >>> --- >>> drivers/acpi/acpica/dsmethod.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/drivers/acpi/acpica/dsmethod.c b/drivers/acpi/acpica/dsmethod.c >>> index ae2e768830bf..19da7fc73186 100644 >>> --- a/drivers/acpi/acpica/dsmethod.c >>> +++ b/drivers/acpi/acpica/dsmethod.c >>> @@ -581,6 +581,7 @@ acpi_ds_call_control_method(struct acpi_thread_state *thread, >>> >>> acpi_ds_terminate_control_method(obj_desc, next_walk_state); >>> acpi_ds_delete_walk_state(next_walk_state); >>> + acpi_ds_pop_walk_state(thread); > On second thought, though, should it be popped before deleting? > Otherwise it looks like there will be still use-after-free, because > acpi_ds_pop_walk_state() accesses the walk_state at the top of the > queue.
You are right it is wrong and sorry I didn't notice that.
I have reproduced same problem on current tree... Have no idea why I missed it before.
I noticed that this patch have been on next-tree so I submitted another one to fix it.
See "ACPICA: Fix pop_walk_state called after walk_state is deleted"
Thanks for your time!
Best,
Chen
> Moreover, it is not correct to pop the walk state if next_walk_state > is NULL AFAICS. > > I'm dropping this one. > > >>> return_ACPI_STATUS(status); >>> } >>> -- >> Bob, this looks correct to me, but I may be missing something in which >> case please let me know.
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