• Julius Werner's avatar
    drivers: char: mem: Check for address space wraparound with mmap() · b299cde2
    Julius Werner authored
    /dev/mem currently allows mmap() mappings that wrap around the end of
    the physical address space, which should probably be illegal. It
    circumvents the existing STRICT_DEVMEM permission check because the loop
    immediately terminates (as the start address is already higher than the
    end address). On the x86_64 architecture it will then cause a panic
    (from the BUG(start >= end) in arch/x86/mm/pat.c:reserve_memtype()).
    
    This patch adds an explicit check to make sure offset + size will not
    wrap around in the physical address type.
    Signed-off-by: default avatarJulius Werner <jwerner@chromium.org>
    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    b299cde2
mem.c 19.7 KB