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authorLecopzer Chen <lecopzer@gmail.com>2021-01-23 21:01:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-01-24 10:34:52 -0800
commita11a496ee6e2ab6ed850233c96b94caf042af0b9 (patch)
treec20b680d7c78de85ab362036593df474c7357c74
parent5c447d274f3746fbed6e695e7b9a2d7bd8b31b71 (diff)
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>
-rw-r--r--mm/kasan/init.c20
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);