linux-kernel - Re: [PATCH v6 06/18] khwasan, arm64: untag virt address in __kimg_to_phys and _virt_addr_is

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAAeHK+xBX4X0oxhjOrjJfwdqcvU80VPhUsi38mEczzHRb01Wew@mail.gmail.com>
Date:   Tue, 18 Sep 2018 19:09:22 +0200
From:   Andrey Konovalov <andreyknvl@...gle.com>
To:     Dmitry Vyukov <dvyukov@...gle.com>
Cc:     Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Alexander Potapenko <glider@...gle.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Christoph Lameter <cl@...ux.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mark Rutland <mark.rutland@....com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Marc Zyngier <marc.zyngier@....com>,
        Dave Martin <dave.martin@....com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        "Eric W . Biederman" <ebiederm@...ssion.com>,
        Ingo Molnar <mingo@...nel.org>,
        Paul Lawrence <paullawrence@...gle.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Arnd Bergmann <arnd@...db.de>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        kasan-dev <kasan-dev@...glegroups.com>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        linux-sparse@...r.kernel.org, Linux-MM <linux-mm@...ck.org>,
        "open list:KERNEL BUILD + fi..." <linux-kbuild@...r.kernel.org>,
        Kostya Serebryany <kcc@...gle.com>,
        Evgeniy Stepanov <eugenis@...gle.com>,
        Lee Smith <Lee.Smith@....com>,
        Ramana Radhakrishnan <Ramana.Radhakrishnan@....com>,
        Jacob Bramley <Jacob.Bramley@....com>,
        Ruben Ayrapetyan <Ruben.Ayrapetyan@....com>,
        Jann Horn <jannh@...gle.com>,
        Mark Brand <markbrand@...gle.com>,
        Chintan Pandya <cpandya@...eaurora.org>,
        Vishwath Mohan <vishwath@...gle.com>
Subject: Re: [PATCH v6 06/18] khwasan, arm64: untag virt address in
 __kimg_to_phys and _virt_addr_is_linear

On Wed, Sep 12, 2018 at 6:33 PM, Dmitry Vyukov <dvyukov@...gle.com> wrote:
> On Wed, Aug 29, 2018 at 1:35 PM, Andrey Konovalov <andreyknvl@...gle.com> wrote:

>> +#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.

Will do in v7.