linux/mm/kasan
Andrey Konovalov 23689e91fb kasan, vmalloc: add vmalloc tagging for HW_TAGS
Add vmalloc tagging support to HW_TAGS KASAN.

The key difference between HW_TAGS and the other two KASAN modes when it
comes to vmalloc: HW_TAGS KASAN can only assign tags to physical memory.
The other two modes have shadow memory covering every mapped virtual
memory region.

Make __kasan_unpoison_vmalloc() for HW_TAGS KASAN:

 - Skip non-VM_ALLOC mappings as HW_TAGS KASAN can only tag a single
   mapping of normal physical memory; see the comment in the function.

 - Generate a random tag, tag the returned pointer and the allocation,
   and initialize the allocation at the same time.

 - Propagate the tag into the page stucts to allow accesses through
   page_address(vmalloc_to_page()).

The rest of vmalloc-related KASAN hooks are not needed:

 - The shadow-related ones are fully skipped.

 - __kasan_poison_vmalloc() is kept as a no-op with a comment.

Poisoning and zeroing of physical pages that are backing vmalloc()
allocations are skipped via __GFP_SKIP_KASAN_UNPOISON and
__GFP_SKIP_ZERO: __kasan_unpoison_vmalloc() does that instead.

Enabling CONFIG_KASAN_VMALLOC with HW_TAGS is not yet allowed.

Link: https://lkml.kernel.org/r/d19b2e9e59a9abc59d05b72dea8429dcaea739c6.1643047180.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Co-developed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-24 19:06:48 -07:00
..
common.c kasan, page_alloc: merge kasan_alloc_pages into post_alloc_hook 2022-03-24 19:06:46 -07:00
generic.c mm/kasan: Convert to struct folio and struct slab 2022-01-06 12:26:14 +01:00
hw_tags.c kasan, vmalloc: add vmalloc tagging for HW_TAGS 2022-03-24 19:06:48 -07:00
init.c kasan: use MAX_PTRS_PER_* for early shadow tables 2021-06-29 10:53:53 -07:00
kasan.h kasan: define KASAN_VMALLOC_INVALID for SW_TAGS 2022-03-24 19:06:47 -07:00
Makefile kasan: integrate the common part of two KASAN tag-based modes 2021-06-29 10:53:53 -07:00
quarantine.c Merge branch 'akpm' (patches from Andrew) 2022-01-15 20:37:06 +02:00
report_generic.c mm/kasan: switch from strlcpy to strscpy 2021-04-30 11:20:41 -07:00
report_hw_tags.c kasan: integrate the common part of two KASAN tag-based modes 2021-06-29 10:53:53 -07:00
report_sw_tags.c kasan: integrate the common part of two KASAN tag-based modes 2021-06-29 10:53:53 -07:00
report_tags.c mm/kasan: Convert to struct folio and struct slab 2022-01-06 12:26:14 +01:00
report.c kasan: no need to unset panic_on_warn in end_report() 2022-03-23 19:00:35 -07:00
shadow.c kasan, vmalloc: add vmalloc tagging for HW_TAGS 2022-03-24 19:06:48 -07:00
sw_tags.c kasan: add kasan mode messages when kasan init 2021-11-11 09:34:35 -08:00
tags.c kasan: integrate the common part of two KASAN tag-based modes 2021-06-29 10:53:53 -07:00