Linux kernel for uConsole
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3b2d69114f
ACPICA commit a23325b2e583556eae88ed3f764e457786bf4df6
I found some ACPI operand cache leaks in ACPI early abort cases.
Boot log of ACPI operand cache leak is as follows:
>[ 0.174332] ACPI: Added _OSI(Module Device)
>[ 0.175504] ACPI: Added _OSI(Processor Device)
>[ 0.176010] ACPI: Added _OSI(3.0 _SCP Extensions)
>[ 0.177032] ACPI: Added _OSI(Processor Aggregator Device)
>[ 0.178284] ACPI: SCI (IRQ16705) allocation failed
>[ 0.179352] ACPI Exception: AE_NOT_ACQUIRED, Unable to install
System Control Interrupt handler (20160930/evevent-131)
>[ 0.180008] ACPI: Unable to start the ACPI Interpreter
>[ 0.181125] ACPI Error: Could not remove SCI handler
(20160930/evmisc-281)
>[ 0.184068] kmem_cache_destroy Acpi-Operand: Slab cache still has
objects
>[ 0.185358] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.10.0-rc3 #2
>[ 0.186820] Hardware name: innotek gmb_h virtual_box/virtual_box, BIOS
virtual_box 12/01/2006
>[ 0.188000] Call Trace:
>[ 0.188000] ? dump_stack+0x5c/0x7d
>[ 0.188000] ? kmem_cache_destroy+0x224/0x230
>[ 0.188000] ? acpi_sleep_proc_init+0x22/0x22
>[ 0.188000] ? acpi_os_delete_cache+0xa/0xd
>[ 0.188000] ? acpi_ut_delete_caches+0x3f/0x7b
>[ 0.188000] ? acpi_terminate+0x5/0xf
>[ 0.188000] ? acpi_init+0x288/0x32e
>[ 0.188000] ? __class_create+0x4c/0x80
>[ 0.188000] ? video_setup+0x7a/0x7a
>[ 0.188000] ? do_one_initcall+0x4e/0x1b0
>[ 0.188000] ? kernel_init_freeable+0x194/0x21a
>[ 0.188000] ? rest_init+0x80/0x80
>[ 0.188000] ? kernel_init+0xa/0x100
>[ 0.188000] ? 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_ns_terminate() function to delete namespace data and ACPI operand cache
(acpi_gbl_module_code_list).
But the deletion code in acpi_ns_terminate() function is wrapped in
ACPI_EXEC_APP definition, therefore the code is only executed when the
definition exists. If the define doesn't exist, ACPI operand cache
(acpi_gbl_module_code_list) is leaked, and stack dump is shown in kernel log.
This causes a security threat because the old kernel (<= 4.9) shows memory
locations of kernel functions in stack dump, therefore kernel ASLR can be
neutralized.
To fix ACPI operand leak for enhancing security, I made a patch which
removes the ACPI_EXEC_APP define in acpi_ns_terminate() function for
executing the deletion code unconditionally.
Link:
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Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.