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| author | Lecopzer Chen <lecopzer@gmail.com> | 2021-01-24 08:01:25 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-01-24 21:34:52 +0300 |
| commit | a11a496ee6e2ab6ed850233c96b94caf042af0b9 (patch) | |
| tree | c20b680d7c78de85ab362036593df474c7357c74 /mm/kasan/init.c | |
| parent | 5c447d274f3746fbed6e695e7b9a2d7bd8b31b71 (diff) | |
| download | linux-a11a496ee6e2ab6ed850233c96b94caf042af0b9.tar.xz | |
kasan: fix unaligned address is unhandled in kasan_remove_zero_shadow
During testing kasan_populate_early_shadow and kasan_remove_zero_shadow,
if the shadow start and end address in kasan_remove_zero_shadow() is not
aligned to PMD_SIZE, the remain unaligned PTE won't be removed.
In the test case for kasan_remove_zero_shadow():
shadow_start: 0xffffffb802000000, shadow end: 0xffffffbfbe000000
3-level page table:
PUD_SIZE: 0x40000000 PMD_SIZE: 0x200000 PAGE_SIZE: 4K
0xffffffbf80000000 ~ 0xffffffbfbdf80000 will not be removed because in
kasan_remove_pud_table(), kasan_pmd_table(*pud) is true but the next
address is 0xffffffbfbdf80000 which is not aligned to PUD_SIZE.
In the correct condition, this should fallback to the next level
kasan_remove_pmd_table() but the condition flow always continue to skip
the unaligned part.
Fix by correcting the condition when next and addr are neither aligned.
Link: https://lkml.kernel.org/r/20210103135621.83129-1-lecopzer@gmail.com
Fixes: 0207df4fa1a86 ("kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN")
Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: YJ Chiang <yj.chiang@mediatek.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/kasan/init.c')
| -rw-r--r-- | mm/kasan/init.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/mm/kasan/init.c b/mm/kasan/init.c index 7ca0b92d5886..91049c1b8994 100644 --- a/mm/kasan/init.c +++ b/mm/kasan/init.c @@ -373,9 +373,10 @@ static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr, if (kasan_pte_table(*pmd)) { if (IS_ALIGNED(addr, PMD_SIZE) && - IS_ALIGNED(next, PMD_SIZE)) + IS_ALIGNED(next, PMD_SIZE)) { pmd_clear(pmd); - continue; + continue; + } } pte = pte_offset_kernel(pmd, addr); kasan_remove_pte_table(pte, addr, next); @@ -398,9 +399,10 @@ static void kasan_remove_pud_table(pud_t *pud, unsigned long addr, if (kasan_pmd_table(*pud)) { if (IS_ALIGNED(addr, PUD_SIZE) && - IS_ALIGNED(next, PUD_SIZE)) + IS_ALIGNED(next, PUD_SIZE)) { pud_clear(pud); - continue; + continue; + } } pmd = pmd_offset(pud, addr); pmd_base = pmd_offset(pud, 0); @@ -424,9 +426,10 @@ static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr, if (kasan_pud_table(*p4d)) { if (IS_ALIGNED(addr, P4D_SIZE) && - IS_ALIGNED(next, P4D_SIZE)) + IS_ALIGNED(next, P4D_SIZE)) { p4d_clear(p4d); - continue; + continue; + } } pud = pud_offset(p4d, addr); kasan_remove_pud_table(pud, addr, next); @@ -457,9 +460,10 @@ void kasan_remove_zero_shadow(void *start, unsigned long size) if (kasan_p4d_table(*pgd)) { if (IS_ALIGNED(addr, PGDIR_SIZE) && - IS_ALIGNED(next, PGDIR_SIZE)) + IS_ALIGNED(next, PGDIR_SIZE)) { pgd_clear(pgd); - continue; + continue; + } } p4d = p4d_offset(pgd, addr); |