• Seunghun Han's avatar
    ACPICA: Namespace: fix operand cache leak · 4c19b00e
    Seunghun Han authored
    commit 3b2d6911 upstream.
    
    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: https://github.com/acpica/acpica/commit/a23325b2Signed-off-by: default avatarSeunghun Han <kkamagui@gmail.com>
    Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
    Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    Acked-by: default avatarLee, Chun-Yi <jlee@suse.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    4c19b00e
nsutils.c 20.1 KB