Hi Abbott, On 10/11/2017 01:22 AM, Abbott Liu wrote: > Hi,all: > These patches add arch specific code for kernel address sanitizer > (see Documentation/kasan.txt). > > 1/8 of kernel addresses reserved for shadow memory. There was no > big enough hole for this, so virtual addresses for shadow were > stolen from user space. > > At early boot stage the whole shadow region populated with just > one physical page (kasan_zero_page). Later, this page reused > as readonly zero shadow for some memory that KASan currently > don't track (vmalloc). > > After mapping the physical memory, pages for shadow memory are > allocated and mapped. > > KASan's stack instrumentation significantly increases stack's > consumption, so CONFIG_KASAN doubles THREAD_SIZE. > > Functions like memset/memmove/memcpy do a lot of memory accesses. > If bad pointer passed to one of these function it is important > to catch this. Compiler's instrumentation cannot do this since > these functions are written in assembly. > > KASan replaces memory functions with manually instrumented variants. > Original functions declared as weak symbols so strong definitions > in mm/kasan/kasan.c could replace them. Original functions have aliases > with '__' prefix in name, so we could call non-instrumented variant > if needed. > > Some files built without kasan instrumentation (e.g. mm/slub.c). > Original mem* function replaced (via #define) with prefixed variants > to disable memory access checks for such files. > > On arm LPAE architecture, the mapping table of KASan shadow memory(if > PAGE_OFFSET is 0xc0000000, the KASan shadow memory's virtual space is > 0xb6e000000~0xbf000000) can't be filled in do_translation_fault function, > because kasan instrumentation maybe cause do_translation_fault function > accessing KASan shadow memory. The accessing of KASan shadow memory in > do_translation_fault function maybe cause dead circle. So the mapping table > of KASan shadow memory need be copyed in pgd_alloc function. > > > Most of the code comes from: > https://github.com/aryabinin/linux/commit/0b54f17e70ff50a902c4af05bb92716eb95acefe. Thanks for putting these patches together, I can't get a kernel to build with ARM_LPAE=y or ARM_LPAE=n that does not result in the following: AS arch/arm/kernel/entry-common.o arch/arm/kernel/entry-common.S: Assembler messages: arch/arm/kernel/entry-common.S:53: Error: invalid constant (ffffffffb6e00000) after fixup arch/arm/kernel/entry-common.S:118: Error: invalid constant (ffffffffb6e00000) after fixup scripts/Makefile.build:412: recipe for target 'arch/arm/kernel/entry-common.o' failed make[3]: *** [arch/arm/kernel/entry-common.o] Error 1 Makefile:1019: recipe for target 'arch/arm/kernel' failed make[2]: *** [arch/arm/kernel] Error 2 make[2]: *** Waiting for unfinished jobs.... This is coming from the increase in TASK_SIZE it seems. This is on top of v4.14-rc4-84-gff5abbe799e2 Thank you > > These patches are tested on vexpress-ca15, vexpress-ca9 > > Cc: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx> > Tested-by: Abbott Liu <liuwenliang@xxxxxxxxxx> > Signed-off-by: Abbott Liu <liuwenliang@xxxxxxxxxx> > > Abbott Liu (6): > Define the virtual space of KASan's shadow region > change memory_is_poisoned_16 for aligned error > Add support arm LPAE > Don't need to map the shadow of KASan's shadow memory > Change mapping of kasan_zero_page int readonly > Add KASan layout > > Andrey Ryabinin (5): > Initialize the mapping of KASan shadow memory > replace memory function > arm: Kconfig: enable KASan > Disable kasan's instrumentation > Avoid cleaning the KASan shadow area's mapping table > > arch/arm/Kconfig | 1 + > arch/arm/boot/compressed/Makefile | 1 + > arch/arm/include/asm/kasan.h | 20 +++ > arch/arm/include/asm/kasan_def.h | 51 +++++++ > arch/arm/include/asm/memory.h | 5 + > arch/arm/include/asm/pgalloc.h | 5 +- > arch/arm/include/asm/pgtable.h | 1 + > arch/arm/include/asm/proc-fns.h | 33 +++++ > arch/arm/include/asm/string.h | 18 ++- > arch/arm/include/asm/thread_info.h | 4 + > arch/arm/kernel/entry-armv.S | 7 +- > arch/arm/kernel/head-common.S | 4 + > arch/arm/kernel/setup.c | 2 + > arch/arm/kernel/unwind.c | 3 +- > arch/arm/lib/memcpy.S | 3 + > arch/arm/lib/memmove.S | 5 +- > arch/arm/lib/memset.S | 3 + > arch/arm/mm/Makefile | 5 + > arch/arm/mm/init.c | 6 + > arch/arm/mm/kasan_init.c | 265 +++++++++++++++++++++++++++++++++++++ > arch/arm/mm/mmu.c | 7 +- > arch/arm/mm/pgd.c | 12 ++ > arch/arm/vdso/Makefile | 2 + > mm/kasan/kasan.c | 22 ++- > 24 files changed, 478 insertions(+), 7 deletions(-) > create mode 100644 arch/arm/include/asm/kasan.h > create mode 100644 arch/arm/include/asm/kasan_def.h > create mode 100644 arch/arm/mm/kasan_init.c > -- Florian -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
