From: Andrey Konovalov <andreyknvl@google.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Christoph Lameter <cl@linux.com>,
Andrew Morton <akpm@linux-foundation.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Marc Zyngier <marc.zyngier@arm.com>,
Dave Martin <dave.martin@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Ingo Molnar <mingo@kernel.org>,
Paul Lawrence <paullawrence@google.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Arnd Bergmann <arnd@arndb.de>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
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Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
Jann Horn <jannh@google.com>, Mark Brand <markbrand@google.com>,
Chintan Pandya <cpandya@codeaurora.org>,
Vishwath Mohan <vishwath@google.com>
Subject: Re: [PATCH v10 07/22] kasan: initialize shadow to 0xff for tag-based mode
Date: Tue, 13 Nov 2018 15:13:22 +0100 [thread overview]
Message-ID: <CAAeHK+wDTDiwT_vcu8tTZyNkqHDdgAtSWF4pp=2mngMaJt44bA@mail.gmail.com> (raw)
In-Reply-To: <20181107170855.n4ertf5qv7ff5btl@lakrids.cambridge.arm.com>
On Wed, Nov 7, 2018 at 6:08 PM, Mark Rutland <mark.rutland@arm.com> wrote:
> On Tue, Nov 06, 2018 at 06:30:22PM +0100, Andrey Konovalov wrote:
>> A tag-based KASAN shadow memory cell contains a memory tag, that
>> corresponds to the tag in the top byte of the pointer, that points to that
>> memory. The native top byte value of kernel pointers is 0xff, so with
>> tag-based KASAN we need to initialize shadow memory to 0xff.
>>
>> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
>> Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
>> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
>> ---
>> arch/arm64/mm/kasan_init.c | 16 ++++++++++++++--
>> include/linux/kasan.h | 8 ++++++++
>> mm/kasan/common.c | 3 ++-
>> 3 files changed, 24 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
>> index 63527e585aac..18ebc8994a7b 100644
>> --- a/arch/arm64/mm/kasan_init.c
>> +++ b/arch/arm64/mm/kasan_init.c
>> @@ -43,6 +43,15 @@ static phys_addr_t __init kasan_alloc_zeroed_page(int node)
>> return __pa(p);
>> }
>>
>> +static phys_addr_t __init kasan_alloc_raw_page(int node)
>> +{
>> + void *p = memblock_alloc_try_nid_raw(PAGE_SIZE, PAGE_SIZE,
>> + __pa(MAX_DMA_ADDRESS),
>> + MEMBLOCK_ALLOC_ACCESSIBLE,
>> + node);
>> + return __pa(p);
>> +}
>> +
>> static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node,
>> bool early)
>> {
>> @@ -88,7 +97,9 @@ static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
>>
>> do {
>> phys_addr_t page_phys = early ? __pa_symbol(kasan_zero_page)
>> - : kasan_alloc_zeroed_page(node);
>> + : kasan_alloc_raw_page(node);
>> + if (!early)
>> + memset(__va(page_phys), KASAN_SHADOW_INIT, PAGE_SIZE);
>> next = addr + PAGE_SIZE;
>> set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
>> } while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)));
>> @@ -138,6 +149,7 @@ asmlinkage void __init kasan_early_init(void)
>> KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));
>> BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
>> BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
>> +
>> kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE,
>> true);
>> }
>> @@ -234,7 +246,7 @@ void __init kasan_init(void)
>> set_pte(&kasan_zero_pte[i],
>> pfn_pte(sym_to_pfn(kasan_zero_page), PAGE_KERNEL_RO));
>>
>> - memset(kasan_zero_page, 0, PAGE_SIZE);
>> + memset(kasan_zero_page, KASAN_SHADOW_INIT, PAGE_SIZE);
>
> If this isn't going to contain zero, can we please have a preparatory
> patch renaming this to something which isn't misleading?
>
> Perhaps kasan_common_shadow_page?
Will rename to kasan_early_shadow_page in v11, thanks!
>
> Thanks,
> Mark.
next prev parent reply other threads:[~2018-11-13 14:13 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-06 17:30 [PATCH v10 00/22] kasan: add software tag-based mode for arm64 Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 01/22] kasan, mm: change hooks signatures Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 02/22] kasan, slub: handle pointer tags in early_kmem_cache_node_alloc Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 03/22] kasan: move common generic and tag-based code to common.c Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 04/22] kasan: rename source files to reflect the new naming scheme Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 05/22] kasan: add CONFIG_KASAN_GENERIC and CONFIG_KASAN_SW_TAGS Andrey Konovalov
2018-11-07 17:04 ` Mark Rutland
2018-11-12 18:21 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 06/22] kasan, arm64: adjust shadow size for tag-based mode Andrey Konovalov
2018-11-07 16:54 ` Mark Rutland
2018-11-12 17:50 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 07/22] kasan: initialize shadow to 0xff " Andrey Konovalov
2018-11-07 17:08 ` Mark Rutland
2018-11-13 14:13 ` Andrey Konovalov [this message]
2018-11-06 17:30 ` [PATCH v10 08/22] kasan, arm64: untag address in __kimg_to_phys and _virt_addr_is_linear Andrey Konovalov
2018-11-07 16:52 ` Mark Rutland
2018-11-14 19:23 ` Andrey Konovalov
2018-11-15 13:43 ` Andrey Konovalov
2018-11-07 18:10 ` Catalin Marinas
2018-11-14 19:52 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 09/22] kasan: add tag related helper functions Andrey Konovalov
2018-11-07 17:23 ` Mark Rutland
2018-11-14 19:19 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 10/22] kasan: preassign tags to objects with ctors or SLAB_TYPESAFE_BY_RCU Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 11/22] mm: move obj_to_index to include/linux/slab_def.h Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 12/22] kasan, arm64: fix up fault handling logic Andrey Konovalov
2018-11-07 18:26 ` Catalin Marinas
2018-11-08 12:22 ` Mark Rutland
2018-11-13 15:01 ` Andrey Konovalov
2018-11-13 22:07 ` Mark Rutland
2018-11-14 20:06 ` Andrey Konovalov
2018-11-14 20:17 ` Mark Rutland
2018-11-15 13:33 ` Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 13/22] kasan, arm64: enable top byte ignore for the kernel Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 14/22] kasan, mm: perform untagged pointers comparison in krealloc Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 15/22] kasan: split out generic_report.c from report.c Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 16/22] kasan: add bug reporting routines for tag-based mode Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 17/22] kasan: add hooks implementation " Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 18/22] kasan, arm64: add brk handler for inline instrumentation Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 19/22] kasan, mm, arm64: tag non slab memory allocated via pagealloc Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 20/22] kasan: add __must_check annotations to kasan hooks Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 21/22] kasan: update documentation Andrey Konovalov
2018-11-06 17:30 ` [PATCH v10 22/22] kasan: add SPDX-License-Identifier mark to source files Andrey Konovalov
2018-11-07 14:56 ` [PATCH v10 00/22] kasan: add software tag-based mode for arm64 Andrey Konovalov
2018-11-07 14:59 ` Will Deacon
2018-11-07 15:11 ` Andrey Konovalov
2018-11-07 15:34 ` Will Deacon
2018-11-07 15:54 ` Andrey Konovalov
2018-11-07 15:56 ` Andrey Konovalov
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