linux-stable.git/mm/kasan, branch linux-4.3.y

kasan: fix last shadow judgement in memory_is_poisoned_16()

2015-09-18T04:16:07+00:00

The shadow which correspond 16 bytes memory may span 2 or 3 bytes.  If
the memory is aligned on 8, then the shadow takes only 2 bytes.  So we
check "shadow_first_bytes" is enough, and need not to call
"memory_is_poisoned_1(addr + 15);".  But the code "if
(likely(!last_byte))" is wrong judgement.

e.g.  addr=0, so last_byte = 15 & KASAN_SHADOW_MASK = 7, then the code
will continue to call "memory_is_poisoned_1(addr + 15);"

Signed-off-by: Xishi Qiu 
Acked-by: Andrey Ryabinin 
Cc: Andrey Konovalov 
Cc: Rusty Russell 
Cc: Michal Marek 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86/kasan, mm: Introduce generic kasan_populate_zero_shadow()

2015-08-22T12:54:55+00:00

Introduce generic kasan_populate_zero_shadow(shadow_start,
shadow_end). This function maps kasan_zero_page to the
[shadow_start, shadow_end] addresses.

This replaces x86_64 specific populate_zero_shadow() and will
be used for ARM64 in follow on patches.

The main changes from original version are:

 * Use p?d_populate*() instead of set_p?d()
 * Use memblock allocator directly instead of vmemmap_alloc_block()
 * __pa() instead of __pa_nodebug(). __pa() causes troubles
   iff we use it before kasan_early_init(). kasan_populate_zero_shadow()
   will be used later, so we ok with __pa() here.

Signed-off-by: Andrey Ryabinin 
Acked-by: Catalin Marinas 
Cc: Alexander Potapenko 
Cc: Alexey Klimov 
Cc: Andrew Morton 
Cc: Aneesh Kumar K.V 
Cc: Arnd Bergmann 
Cc: David Keitel 
Cc: Dmitry Vyukov 
Cc: Linus Torvalds 
Cc: Linus Walleij 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Cc: Yury 
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1439444244-26057-3-git-send-email-ryabinin.a.a@gmail.com
Signed-off-by: Ingo Molnar

.mailmap: Andrey Ryabinin has moved

2015-08-14T22:56:32+00:00

Update my email address.

Signed-off-by: Andrey Ryabinin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan: remove duplicate definition of the macro KASAN_FREE_PAGE

2015-06-26T00:00:42+00:00

Remove duplicate definition of the macro KASAN_FREE_PAGE in
mm/kasan/kasan.h

Signed-off-by: Wang Long 
Acked-by: Andrey Ryabinin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/mempool.c: kasan: poison mempool elements

2015-04-15T23:35:20+00:00

Mempools keep allocated objects in reserved for situations when ordinary
allocation may not be possible to satisfy.  These objects shouldn't be
accessed before they leave the pool.

This patch poison elements when get into the pool and unpoison when they
leave it.  This will let KASan to detect use-after-free of mempool's
elements.

Signed-off-by: Andrey Ryabinin 
Tested-by: David Rientjes 
Cc: Catalin Marinas 
Cc: Dmitry Chernenkov 
Cc: Dmitry Vyukov 
Cc: Alexander Potapenko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan, module, vmalloc: rework shadow allocation for modules

2015-03-13T01:46:08+00:00

Current approach in handling shadow memory for modules is broken.

Shadow memory could be freed only after memory shadow corresponds it is no
longer used.  vfree() called from interrupt context could use memory its
freeing to store 'struct llist_node' in it:

    void vfree(const void *addr)
    {
    ...
        if (unlikely(in_interrupt())) {
            struct vfree_deferred *p = this_cpu_ptr(&vfree_deferred);
            if (llist_add((struct llist_node *)addr, &p->list))
                    schedule_work(&p->wq);

Later this list node used in free_work() which actually frees memory.
Currently module_memfree() called in interrupt context will free shadow
before freeing module's memory which could provoke kernel crash.

So shadow memory should be freed after module's memory.  However, such
deallocation order could race with kasan_module_alloc() in module_alloc().

Free shadow right before releasing vm area.  At this point vfree()'d
memory is not used anymore and yet not available for other allocations.
New VM_KASAN flag used to indicate that vm area has dynamically allocated
shadow memory so kasan frees shadow only if it was previously allocated.

Signed-off-by: Andrey Ryabinin 
Acked-by: Rusty Russell 
Cc: Dmitry Vyukov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan: enable instrumentation of global variables

2015-02-14T05:21:42+00:00

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: Andrey Ryabinin 
Cc: Dmitry Vyukov 
Cc: Konstantin Serebryany 
Cc: Dmitry Chernenkov 
Signed-off-by: Andrey Konovalov 
Cc: Yuri Gribov 
Cc: Konstantin Khlebnikov 
Cc: Sasha Levin 
Cc: Christoph Lameter 
Cc: Joonsoo Kim 
Cc: Dave Hansen 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan: enable stack instrumentation

2015-02-14T05:21:41+00:00

Stack instrumentation allows to detect out of bounds memory accesses for
variables allocated on stack.  Compiler adds redzones around every
variable on stack and poisons redzones in function's prologue.

Such approach significantly increases stack usage, so all in-kernel stacks
size were doubled.

Signed-off-by: Andrey Ryabinin 
Cc: Dmitry Vyukov 
Cc: Konstantin Serebryany 
Cc: Dmitry Chernenkov 
Signed-off-by: Andrey Konovalov 
Cc: Yuri Gribov 
Cc: Konstantin Khlebnikov 
Cc: Sasha Levin 
Cc: Christoph Lameter 
Cc: Joonsoo Kim 
Cc: Dave Hansen 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86_64: kasan: add interceptors for memset/memmove/memcpy functions

2015-02-14T05:21:41+00:00

Recently instrumentation of builtin functions calls was removed from GCC
5.0.  To check the memory accessed by such functions, userspace asan
always uses interceptors for them.

So now we should do this as well.  This patch declares
memset/memmove/memcpy as weak symbols.  In mm/kasan/kasan.c we have our
own implementation of those functions which checks memory before accessing
it.

Default memset/memmove/memcpy now now always have aliases with '__'
prefix.  For files that built without kasan instrumentation (e.g.
mm/slub.c) original mem* replaced (via #define) with prefixed variants,
cause we don't want to check memory accesses there.

Signed-off-by: Andrey Ryabinin 
Cc: Dmitry Vyukov 
Cc: Konstantin Serebryany 
Cc: Dmitry Chernenkov 
Signed-off-by: Andrey Konovalov 
Cc: Yuri Gribov 
Cc: Konstantin Khlebnikov 
Cc: Sasha Levin 
Cc: Christoph Lameter 
Cc: Joonsoo Kim 
Cc: Dave Hansen 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: slub: add kernel address sanitizer support for slub allocator

2015-02-14T05:21:41+00:00

With this patch kasan will be able to catch bugs in memory allocated by
slub.  Initially all objects in newly allocated slab page, marked as
redzone.  Later, when allocation of slub object happens, requested by
caller number of bytes marked as accessible, and the rest of the object
(including slub's metadata) marked as redzone (inaccessible).

We also mark object as accessible if ksize was called for this object.
There is some places in kernel where ksize function is called to inquire
size of really allocated area.  Such callers could validly access whole
allocated memory, so it should be marked as accessible.

Code in slub.c and slab_common.c files could validly access to object's
metadata, so instrumentation for this files are disabled.

Signed-off-by: Andrey Ryabinin 
Signed-off-by: Dmitry Chernenkov 
Cc: Dmitry Vyukov 
Cc: Konstantin Serebryany 
Signed-off-by: Andrey Konovalov 
Cc: Yuri Gribov 
Cc: Konstantin Khlebnikov 
Cc: Sasha Levin 
Cc: Christoph Lameter 
Cc: Joonsoo Kim 
Cc: Dave Hansen 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds