• David Brownell's avatar
    RTCs: handle NVRAM better · a4b1d50e
    David Brownell authored
    Several of the RTC drivers are exporting binary "nvram" files in sysfs.  Such
    NVRAM (or on many systems, EEPROM) data is often initialized during system
    manufacture to hold data about identity (serial numbers, Ethernet addresses,
    etc), configuration, calibration, and so forth.
    
    This patch improves integrity and security of those files:
    
      - Correctly initializes the size in one of the two cases where
        that was not yet being done.
    
      - Improves system security/integrity by making this state not
        be world-writable by default.
    
    Letting arbitrary userspace code mangle such state by default is at least Not
    A Good Thing; and it could sometimes be worse, depending on the particular
    data that might be corrupted.  (I disregard the paranoiac "don't let anyone
    read it either" approach.  Anyone storing passwords in such memory doesn't
    really care about security.)
    Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
    Acked-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
    Cc: Torsten Ertbjerg Rasmussen <tr@newtec.dk>
    Cc: Mark Zhan <rongkai.zhan@windriver.com>
    Cc: Thomas Hommel <thomas.hommel@gefanuc.com>
    Acked-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    a4b1d50e
rtc-m48t59.c 13.2 KB