From 4a0243ecb4c94e2d73510d096c5ea4d0711fc6c0 Mon Sep 17 00:00:00 2001
From: Seunghun Han <kkamagui@gmail.com>
Date: Fri, 23 Jun 2017 14:19:48 +0900
Subject: [PATCH] acpi: acpica: fix acpi parse and parseext cache leaks
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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 GmbH VirtualBox/VirtualBox, BIOS
VirtualBox 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-ParseExt” 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 GmbH VirtualBox/VirtualBox, BIOS
VirtualBox 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-ParseExt: 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 GmbH VirtualBox/VirtualBox, BIOS
VirtualBox 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 have flush codes to
handle an error state due to invalid AML codes.
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 which has
flush codes in acpi_ps_parse_loop() function.
I hope that this patch improves the security of Linux kernel.
Thank you.
Signed-off-by: Seunghun Han <kkamagui@gmail.com>
Github-Location: https://github.com/acpica/acpica/pull/278/commits/4a0243ecb4c94e2d73510d096c5ea4d0711fc6c0
---
source/components/parser/psobject.c | 44 ++++++++++++++-----------------------
1 file changed, 16 insertions(+), 28 deletions(-)
Index: acpica-unix2-20200925/source/components/parser/psobject.c
===================================================================
--- acpica-unix2-20200925.orig/source/components/parser/psobject.c
+++ acpica-unix2-20200925/source/components/parser/psobject.c
@@ -707,7 +707,8 @@ AcpiPsCompleteFinalOp (
ACPI_PARSE_OBJECT *Op,
ACPI_STATUS Status)
{
- ACPI_STATUS Status2;
+ ACPI_STATUS ReturnStatus = AE_OK;
+ BOOLEAN Ascending = TRUE;
ACPI_FUNCTION_TRACE_PTR (PsCompleteFinalOp, WalkState);
@@ -724,7 +725,7 @@ AcpiPsCompleteFinalOp (
{
if (Op)
{
- if (WalkState->AscendingCallback != NULL)
+ if (Ascending && WalkState->AscendingCallback != NULL)
{
WalkState->Op = Op;
WalkState->OpInfo = AcpiPsGetOpcodeInfo (Op->Common.AmlOpcode);
@@ -743,41 +744,28 @@ AcpiPsCompleteFinalOp (
if (Status == AE_CTRL_TERMINATE)
{
- Status = AE_OK;
-
- /* Clean up */
- do
- {
- if (Op)
- {
- Status2 = AcpiPsCompleteThisOp (WalkState, Op);
- if (ACPI_FAILURE (Status2))
- {
- return_ACPI_STATUS (Status2);
- }
- }
-
- AcpiPsPopScope (&(WalkState->ParserState), &Op,
- &WalkState->ArgTypes, &WalkState->ArgCount);
-
- } while (Op);
-
- return_ACPI_STATUS (Status);
+ Ascending = FALSE;
+ ReturnStatus = AE_CTRL_TERMINATE;
}
else if (ACPI_FAILURE (Status))
{
/* First error is most important */
- (void) AcpiPsCompleteThisOp (WalkState, Op);
- return_ACPI_STATUS (Status);
+ Ascending = FALSE;
+ ReturnStatus = Status;
}
}
- Status2 = AcpiPsCompleteThisOp (WalkState, Op);
- if (ACPI_FAILURE (Status2))
+ Status = AcpiPsCompleteThisOp (WalkState, Op);
+ if (ACPI_FAILURE (Status))
{
- return_ACPI_STATUS (Status2);
+ Ascending = FALSE;
+ if (ACPI_SUCCESS (ReturnStatus) ||
+ ReturnStatus == AE_CTRL_TERMINATE)
+ {
+ ReturnStatus = Status;
+ }
}
}
@@ -786,5 +774,5 @@ AcpiPsCompleteFinalOp (
} while (Op);
- return_ACPI_STATUS (Status);
+ return_ACPI_STATUS (ReturnStatus);
}