From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, andreyknvl@google.com,
aryabinin@virtuozzo.com, dan.j.williams@intel.com,
dvyukov@google.com, glider@google.com,
lecopzer.chen@mediatek.com, lecopzer@gmail.com,
linux-mm@kvack.org, mm-commits@vger.kernel.org,
torvalds@linux-foundation.org, yj.chiang@mediatek.com
Subject: [patch 07/19] kasan: fix unaligned address is unhandled in kasan_remove_zero_shadow
Date: Sat, 23 Jan 2021 21:01:25 -0800 [thread overview]
Message-ID: <20210124050125.TPTFvoKBt%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210123210029.a7c704d0cab204683e41ad10@linux-foundation.org>
From: Lecopzer Chen <lecopzer@gmail.com>
Subject: 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>
---
mm/kasan/init.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
--- a/mm/kasan/init.c~kasan-fix-unaligned-address-is-unhandled-in-kasan_remove_zero_shadow
+++ a/mm/kasan/init.c
@@ -373,9 +373,10 @@ static void kasan_remove_pmd_table(pmd_t
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
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
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 *star
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);
_
next prev parent reply other threads:[~2021-01-24 5:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-24 5:00 incoming Andrew Morton
2021-01-24 5:00 ` [patch 01/19] x86/setup: don't remove E820_TYPE_RAM for pfn 0 Andrew Morton
2021-01-24 5:01 ` [patch 02/19] mm: fix initialization of struct page for holes in memory layout Andrew Morton
2021-01-24 5:01 ` [patch 03/19] mm: memcg/slab: optimize objcg stock draining Andrew Morton
2021-01-24 5:01 ` [patch 04/19] mm: memcg: fix memcg file_dirty numa stat Andrew Morton
2021-01-24 5:01 ` [patch 05/19] mm: fix numa stats for thp migration Andrew Morton
2021-01-24 5:01 ` [patch 06/19] mm: memcontrol: prevent starvation when writing memory.high Andrew Morton
2021-01-24 18:01 ` Shakeel Butt
2021-01-24 18:35 ` Linus Torvalds
2021-01-24 5:01 ` Andrew Morton [this message]
2021-01-24 5:01 ` [patch 08/19] kasan: fix incorrect arguments passing in kasan_add_zero_shadow Andrew Morton
2021-01-24 5:01 ` [patch 09/19] kasan: fix HW_TAGS boot parameters Andrew Morton
2021-01-24 5:01 ` [patch 10/19] kasan, mm: fix conflicts with init_on_alloc/free Andrew Morton
2021-01-24 5:01 ` [patch 11/19] kasan, mm: fix resetting page_alloc tags for HW_TAGS Andrew Morton
2021-01-24 5:01 ` [patch 12/19] ubsan: disable unsigned-overflow check for i386 Andrew Morton
2021-01-24 5:01 ` [patch 13/19] mm: fix page reference leak in soft_offline_page() Andrew Morton
2021-01-24 5:01 ` [patch 14/19] sparc/mm/highmem: flush cache and TLB Andrew Morton
2021-01-24 5:02 ` [patch 15/19] mm/highmem: prepare for overriding set_pte_at() Andrew Morton
2021-01-24 5:02 ` [patch 16/19] mips/mm/highmem: use set_pte() for kmap_local() Andrew Morton
2021-01-24 5:02 ` [patch 17/19] powerpc/mm/highmem: use __set_pte_at() " Andrew Morton
2021-01-24 5:02 ` [patch 18/19] proc_sysctl: fix oops caused by incorrect command parameters Andrew Morton
2021-01-24 5:02 ` [patch 19/19] MAINTAINERS: add a couple more files to the Clang/LLVM section Andrew Morton
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