• Andrey Ryabinin's avatar
    kasan: enable instrumentation of global variables · bebf56a1
    Andrey Ryabinin authored
    
    
    This feature let us to detect accesses out of bounds of global variables.
    This will work as for globals in kernel image, so for globals in modules.
    Currently this won't work for symbols in user-specified sections (e.g.
    __init, __read_mostly, ...)
    
    The idea of this is simple.  Compiler increases each global variable by
    redzone size and add constructors invoking __asan_register_globals()
    function.  Information about global variable (address, size, size with
    redzone ...) passed to __asan_register_globals() so we could poison
    variable's redzone.
    
    This patch also forces module_alloc() to return 8*PAGE_SIZE aligned
    address making shadow memory handling (
    kasan_module_alloc()/kasan_module_free() ) more simple.  Such alignment
    guarantees that each shadow page backing modules address space correspond
    to only one module_alloc() allocation.
    Signed-off-by: default avatarAndrey Ryabinin <a.ryabinin@samsung.com>
    Cc: Dmitry Vyukov <dvyukov@google.com>
    Cc: Konstantin Serebryany <kcc@google.com>
    Cc: Dmitry Chernenkov <dmitryc@google.com>
    Signed-off-by: default avatarAndrey Konovalov <adech.fo@gmail.com>
    Cc: Yuri Gribov <tetra2005@gmail.com>
    Cc: Konstantin Khlebnikov <koct9i@gmail.com>
    Cc: Sasha Levin <sasha.levin@oracle.com>
    Cc: Christoph Lameter <cl@linux.com>
    Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
    Cc: Dave Hansen <dave.hansen@intel.com>
    Cc: Andi Kleen <andi@firstfloor.org>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Christoph Lameter <cl@linux.com>
    Cc: Pekka Enberg <penberg@kernel.org>
    Cc: David Rientjes <rientjes@google.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    bebf56a1
kasan.c 12 KB