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From 987a3b5cf7175916e2a4b6ea5b8e70f830dfe732 Mon Sep 17 00:00:00 2001
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From: Seunghun Han <kkamagui@gmail.com>
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Date: Wed, 19 Jul 2017 16:47:53 +0900
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Subject: [PATCH] acpi: acpica: fix acpi operand cache leak in dswstate.c
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I found an ACPI cache leak in ACPI early termination and boot continuing case.
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When early termination occurs due to malicious ACPI table, Linux kernel
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terminates ACPI function and continues to boot process. While kernel terminates
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ACPI function, kmem_cache_destroy() reports Acpi-Operand cache leak.
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Boot log of ACPI operand cache leak is as follows:
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>[ 0.585957] ACPI: Added _OSI(Module Device)
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>[ 0.587218] ACPI: Added _OSI(Processor Device)
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>[ 0.588530] ACPI: Added _OSI(3.0 _SCP Extensions)
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>[ 0.589790] ACPI: Added _OSI(Processor Aggregator Device)
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>[ 0.591534] ACPI Error: Illegal I/O port address/length above 64K: C806E00000004002/0x2 (20170303/hwvalid-155)
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>[ 0.594351] ACPI Exception: AE_LIMIT, Unable to initialize fixed events (20170303/evevent-88)
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>[ 0.597858] ACPI: Unable to start the ACPI Interpreter
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>[ 0.599162] ACPI Error: Could not remove SCI handler (20170303/evmisc-281)
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>[ 0.601836] kmem_cache_destroy Acpi-Operand: Slab cache still has objects
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>[ 0.603556] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0-rc5 #26
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>[ 0.605159] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
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>[ 0.609177] Call Trace:
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>[ 0.610063] ? dump_stack+0x5c/0x81
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>[ 0.611118] ? kmem_cache_destroy+0x1aa/0x1c0
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>[ 0.612632] ? acpi_sleep_proc_init+0x27/0x27
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>[ 0.613906] ? acpi_os_delete_cache+0xa/0x10
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>[ 0.617986] ? acpi_ut_delete_caches+0x3f/0x7b
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>[ 0.619293] ? acpi_terminate+0xa/0x14
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>[ 0.620394] ? acpi_init+0x2af/0x34f
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>[ 0.621616] ? __class_create+0x4c/0x80
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>[ 0.623412] ? video_setup+0x7f/0x7f
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>[ 0.624585] ? acpi_sleep_proc_init+0x27/0x27
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>[ 0.625861] ? do_one_initcall+0x4e/0x1a0
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>[ 0.627513] ? kernel_init_freeable+0x19e/0x21f
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>[ 0.628972] ? rest_init+0x80/0x80
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>[ 0.630043] ? kernel_init+0xa/0x100
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>[ 0.631084] ? ret_from_fork+0x25/0x30
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>[ 0.633343] vgaarb: loaded
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>[ 0.635036] EDAC MC: Ver: 3.0.0
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>[ 0.638601] PCI: Probing PCI hardware
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>[ 0.639833] PCI host bridge to bus 0000:00
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>[ 0.641031] pci_bus 0000:00: root bus resource [io 0x0000-0xffff]
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> ... Continue to boot and log is omitted ...
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I analyzed this memory leak in detail and found acpi_ds_obj_stack_pop_and_
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delete() function miscalculated the top of the stack. acpi_ds_obj_stack_push()
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function uses walk_state->operand_index for start position of the top, but
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acpi_ds_obj_stack_pop_and_delete() function considers index 0 for it.
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Therefore, this causes acpi operand memory leak.
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This cache leak causes a security threat because an old kernel (<= 4.9) shows
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memory locations of kernel functions in stack dump. Some malicious users
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could use this information to neutralize kernel ASLR.
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I made a patch to fix ACPI operand cache leak.
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Signed-off-by: Seunghun Han <kkamagui@gmail.com>
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Github-Location: https://github.com/acpica/acpica/pull/295/commits/987a3b5cf7175916e2a4b6ea5b8e70f830dfe732
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---
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source/components/dispatcher/dsutils.c | 9 ++++++++-
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1 file changed, 8 insertions(+), 1 deletion(-)
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Index: acpica-unix2-20180209/source/components/dispatcher/dsutils.c
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===================================================================
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--- acpica-unix2-20180209.orig/source/components/dispatcher/dsutils.c
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+++ acpica-unix2-20180209/source/components/dispatcher/dsutils.c
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@@ -761,6 +761,8 @@ AcpiDsCreateOperands (
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ACPI_PARSE_OBJECT *Arguments[ACPI_OBJ_NUM_OPERANDS];
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UINT32 ArgCount = 0;
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UINT32 Index = WalkState->NumOperands;
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+ UINT32 PrevNumOperands = WalkState->NumOperands;
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+ UINT32 NewNumOperands;
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UINT32 i;
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@@ -793,6 +795,7 @@ AcpiDsCreateOperands (
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/* Create the interpreter arguments, in reverse order */
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+ NewNumOperands = Index;
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Index--;
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for (i = 0; i < ArgCount; i++)
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{
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@@ -820,7 +823,11 @@ Cleanup:
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* pop everything off of the operand stack and delete those
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* objects
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*/
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- AcpiDsObjStackPopAndDelete (ArgCount, WalkState);
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+ WalkState->NumOperands = i;
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+ AcpiDsObjStackPopAndDelete (NewNumOperands, WalkState);
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+
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+ /* Restore operand count */
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+ WalkState->NumOperands = PrevNumOperands;
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ACPI_EXCEPTION ((AE_INFO, Status, "While creating Arg %u", Index));
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return_ACPI_STATUS (Status);
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