From: Dmitry Vyukov <dvyukov@google.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@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>,
Mark Rutland <mark.rutland@arm.com>,
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>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
kasan-dev <kasan-dev@googlegroups.com>,
linux-doc@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-sparse@vger.kernel.org, Linux-MM <linux-mm@kvack.org>,
"open list:KERNEL BUILD + fi..." <linux-kbuild@vger.kernel.org>,
Kostya Serebryany <kcc@google.com>,
Evgeniy Stepanov <eugenis@google.com>,
Lee Smith <Lee.Smith@arm.com>,
Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
Jacob Bramley <Jacob.Bramley@arm.com>,
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 v6 06/18] khwasan, arm64: untag virt address in __kimg_to_phys and _virt_addr_is_linear
Date: Wed, 12 Sep 2018 18:33:56 +0200 [thread overview]
Message-ID: <CACT4Y+aJ36LGLG=TVOGQoJ+fB4Xc9CjdxAs8KZpUm3AsNEoHFw@mail.gmail.com> (raw)
In-Reply-To: <19d757c2cafc277f0143a8ac34e179061f3487f5.1535462971.git.andreyknvl@google.com>
On Wed, Aug 29, 2018 at 1:35 PM, Andrey Konovalov <andreyknvl@google.com> wrote:
> __kimg_to_phys (which is used by virt_to_phys) and _virt_addr_is_linear
> (which is used by virt_addr_valid) assume that the top byte of the address
> is 0xff, which isn't always the case with KHWASAN enabled.
>
> The solution is to reset the tag in those macros.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---
> arch/arm64/include/asm/memory.h | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> index f5e262ee76c1..f5e2953b7009 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -92,6 +92,13 @@
> #define KASAN_THREAD_SHIFT 0
> #endif
>
> +#ifdef CONFIG_KASAN_HW
> +#define KASAN_TAG_SHIFTED(tag) ((unsigned long)(tag) << 56)
> +#define KASAN_SET_TAG(addr, tag) (((addr) & ~KASAN_TAG_SHIFTED(0xff)) | \
> + KASAN_TAG_SHIFTED(tag))
> +#define KASAN_RESET_TAG(addr) KASAN_SET_TAG(addr, 0xff)
> +#endif
> +
Wouldn't it be better to
#define KASAN_RESET_TAG(addr) addr
when CONFIG_KASAN_HW is not enabled, and then not duplicate the macros
below? That's what we do in kasan.h for all hooks.
I see that a subsequent patch duplicates yet another macro in this
file. While we could use:
#define __kimg_to_phys(addr) (KASAN_RESET_TAG(addr) - kimage_voffset)
with and without kasan. Duplicating them increases risk that somebody
will change only the non-kasan version but forget kasan version.
> #define MIN_THREAD_SHIFT (14 + KASAN_THREAD_SHIFT)
>
> /*
> @@ -232,7 +239,12 @@ static inline unsigned long kaslr_offset(void)
> #define __is_lm_address(addr) (!!((addr) & BIT(VA_BITS - 1)))
>
> #define __lm_to_phys(addr) (((addr) & ~PAGE_OFFSET) + PHYS_OFFSET)
> +
> +#ifdef CONFIG_KASAN_HW
> +#define __kimg_to_phys(addr) (KASAN_RESET_TAG(addr) - kimage_voffset)
> +#else
> #define __kimg_to_phys(addr) ((addr) - kimage_voffset)
> +#endif
>
> #define __virt_to_phys_nodebug(x) ({ \
> phys_addr_t __x = (phys_addr_t)(x); \
> @@ -308,7 +320,13 @@ static inline void *phys_to_virt(phys_addr_t x)
> #endif
> #endif
>
> +#ifdef CONFIG_KASAN_HW
> +#define _virt_addr_is_linear(kaddr) (KASAN_RESET_TAG((u64)(kaddr)) >= \
> + PAGE_OFFSET)
> +#else
> #define _virt_addr_is_linear(kaddr) (((u64)(kaddr)) >= PAGE_OFFSET)
> +#endif
> +
> #define virt_addr_valid(kaddr) (_virt_addr_is_linear(kaddr) && \
> _virt_addr_valid(kaddr))
>
> --
> 2.19.0.rc0.228.g281dcd1b4d0-goog
>
next prev parent reply other threads:[~2018-09-12 16:34 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-29 11:35 [PATCH v6 00/18] khwasan: kernel hardware assisted address sanitizer Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 01/18] khwasan, mm: change kasan hooks signatures Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 02/18] khwasan: move common kasan and khwasan code to common.c Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 03/18] khwasan: add CONFIG_KASAN_GENERIC and CONFIG_KASAN_HW Andrey Konovalov
2018-09-12 14:47 ` Dmitry Vyukov
2018-09-12 14:51 ` Dmitry Vyukov
2018-09-17 18:42 ` Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 04/18] khwasan, arm64: adjust shadow size for CONFIG_KASAN_HW Andrey Konovalov
2018-09-12 14:54 ` Dmitry Vyukov
2018-09-19 17:27 ` Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 05/18] khwasan: initialize shadow to 0xff Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 06/18] khwasan, arm64: untag virt address in __kimg_to_phys and _virt_addr_is_linear Andrey Konovalov
2018-09-12 16:33 ` Dmitry Vyukov [this message]
2018-09-18 17:09 ` Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 07/18] khwasan: add tag related helper functions Andrey Konovalov
2018-09-12 16:21 ` Dmitry Vyukov
2018-09-17 18:59 ` Andrey Konovalov
2018-09-18 15:45 ` Dmitry Vyukov
2018-08-29 11:35 ` [PATCH v6 08/18] khwasan: preassign tags to objects with ctors or SLAB_TYPESAFE_BY_RCU Andrey Konovalov
2018-09-12 16:36 ` Dmitry Vyukov
2018-09-18 16:50 ` Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 09/18] khwasan, arm64: fix up fault handling logic Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 10/18] khwasan, arm64: enable top byte ignore for the kernel Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 11/18] khwasan, mm: perform untagged pointers comparison in krealloc Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 12/18] khwasan: split out kasan_report.c from report.c Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 13/18] khwasan: add bug reporting routines Andrey Konovalov
2018-09-12 17:50 ` Dmitry Vyukov
2018-09-18 17:36 ` Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 14/18] khwasan: add hooks implementation Andrey Konovalov
2018-09-12 18:30 ` Dmitry Vyukov
2018-09-19 11:54 ` Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 15/18] khwasan, arm64: add brk handler for inline instrumentation Andrey Konovalov
2018-09-12 17:13 ` Dmitry Vyukov
2018-09-17 19:12 ` Andrey Konovalov
2018-09-12 17:15 ` Dmitry Vyukov
2018-09-12 17:39 ` Jann Horn
2018-09-13 8:37 ` Dmitry Vyukov
2018-09-13 18:09 ` Nick Desaulniers
2018-09-13 18:23 ` Jann Horn
2018-09-14 5:11 ` Dmitry Vyukov
2018-08-29 11:35 ` [PATCH v6 16/18] khwasan, mm, arm64: tag non slab memory allocated via pagealloc Andrey Konovalov
2018-09-07 16:06 ` Andrey Ryabinin
2018-09-11 16:10 ` Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 17/18] khwasan: update kasan documentation Andrey Konovalov
2018-09-12 18:39 ` Dmitry Vyukov
2018-09-18 18:42 ` Andrey Konovalov
2018-08-29 11:35 ` [PATCH v6 18/18] kasan: add SPDX-License-Identifier mark to source files Andrey Konovalov
2018-09-05 21:10 ` [PATCH v6 00/18] khwasan: kernel hardware assisted address sanitizer Andrew Morton
2018-09-05 21:55 ` Nick Desaulniers
2018-09-06 10:05 ` Will Deacon
2018-09-06 11:06 ` Andrey Konovalov
2018-09-06 16:39 ` Nick Desaulniers
2018-09-14 15:28 ` Will Deacon
2018-09-19 18:53 ` Andrey Konovalov
2018-09-07 16:10 ` Andrey Ryabinin
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