The patch titled
Subject: kasan, mm: fix resetting page_alloc tags for HW_TAGS
has been added to the -mm tree. Its filename is
kasan-mm-fix-resetting-page_alloc-tags-for-hw_tags.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-mm-fix-resetting-page_alloc-tags-for-hw_tags.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-mm-fix-resetting-page_alloc-tags-for-hw_tags.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan, mm: fix resetting page_alloc tags for HW_TAGS
A previous commit added resetting KASAN page tags to
kernel_init_free_pages() to avoid false-positives due to accesses to
metadata with the hardware tag-based mode.
That commit did reset page tags before the metadata access, but didn't
restore them after. As the result, KASAN fails to detect bad accesses to
page_alloc allocations on some configurations.
Fix this by recovering the tag after the metadata access.
Link: https://lkml.kernel.org/r/02b5bcd692e912c27d484030f666b350ad7e4ae4.1611074450.git.andreyknvl@xxxxxxxxxx
Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing metadata")
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 2 ++
1 file changed, 2 insertions(+)
--- a/mm/page_alloc.c~kasan-mm-fix-resetting-page_alloc-tags-for-hw_tags
+++ a/mm/page_alloc.c
@@ -1207,8 +1207,10 @@ static void kernel_init_free_pages(struc
/* s390's use of memset() could override KASAN redzones. */
kasan_disable_current();
for (i = 0; i < numpages; i++) {
+ u8 tag = page_kasan_tag(page + i);
page_kasan_tag_reset(page + i);
clear_highpage(page + i);
+ page_kasan_tag_set(page + i, tag);
}
kasan_enable_current();
}
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-fix-hw_tags-boot-parameters.patch
kasan-mm-fix-conflicts-with-init_on_alloc-free.patch
kasan-mm-fix-resetting-page_alloc-tags-for-hw_tags.patch
kasan-prefix-global-functions-with-kasan_.patch
kasan-clarify-hw_tags-impact-on-tbi.patch
kasan-clean-up-comments-in-tests.patch
kasan-add-macros-to-simplify-checking-test-constraints.patch
kasan-add-match-all-tag-tests.patch
kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode.patch
kasan-rename-config_test_kasan_module.patch
kasan-add-compiler-barriers-to-kunit_expect_kasan_fail.patch
kasan-adapt-kmalloc_uaf2-test-to-hw_tags-mode.patch
kasan-fix-memory-corruption-in-kasan_bitops_tags-test.patch
kasan-move-_ret_ip_-to-inline-wrappers.patch
kasan-fix-bug-detection-via-ksize-for-hw_tags-mode.patch
kasan-add-proper-page-allocator-tests.patch
kasan-add-a-test-for-kmem_cache_alloc-free_bulk.patch
kasan-dont-run-tests-when-kasan-is-not-enabled.patch
