• Jean Delvare's avatar
    firmware: dmi_scan: Fix ordering of product_uuid · b7314518
    Jean Delvare authored
    commit 5c1ac56b upstream.
    
    In function dmi_present(), dmi_walk_early() calls dmi_table(), which
    calls dmi_decode(), which ultimately calls dmi_save_uuid(). This last
    function makes a decision based on the value of global variable
    dmi_ver. The problem is that this variable is set right _after_
    dmi_walk_early() returns. So dmi_save_uuid() always sees dmi_ver == 0
    regardless of the actual version implemented.
    
    This causes /sys/class/dmi/id/product_uuid to always use the old
    ordering even on systems implementing DMI/SMBIOS 2.6 or later, which
    should use the new ordering.
    
    This is broken since kernel v3.8 for legacy DMI implementations and
    since kernel v3.10 for SMBIOS 2 implementations. SMBIOS 3
    implementations with the 64-bit entry point are not affected.
    
    The first breakage does not matter much as in practice legacy DMI
    implementations are always for versions older than 2.6, which is when
    the UUID ordering changed. The second breakage is more problematic as
    it affects the vast majority of x86 systems manufactured since 2009.
    Signed-off-by: default avatarJean Delvare <jdelvare@suse.de>
    Fixes: 9f9c9cbb ("drivers/firmware/dmi_scan.c: fetch dmi version from SMBIOS if it exists")
    Fixes: 79bae42d ("dmi_scan: refactor dmi_scan_machine(), {smbios,dmi}_present()")
    Acked-by: default avatarZhenzhong Duan <zhenzhong.duan@oracle.com>
    Cc: Ben Hutchings <ben@decadent.org.uk>
    Cc: Artem Savkov <artem.savkov@gmail.com>
    Cc: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
    Cc: Matt Fleming <matt.fleming@intel.com>
    [bwh: Backported to 3.2: adjust context]
    Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
    b7314518
dmi_scan.c 18.6 KB