From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Jonathan Corbet <corbet@lwn.net>,
Mark Rutland <mark.rutland@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Al Viro <viro@zeniv.linux.org.uk>,
James Morse <james.morse@arm.com>,
Kees Cook <keescook@chromium.org>,
Bart Van Assche <bart.vanassche@wdc.com>,
Kate Stewart <kstewart@linuxfoundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Philippe Ombredanne <pombredanne@nexb.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
Zi Yan <zi.yan@cs.rutgers.edu>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-doc@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Jacob Bramley <Jacob.Bramley@arm.com>,
Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
Lee Smith <Lee.Smith@arm.com>, Kostya Serebryany <kcc@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
Evgeniy Stepanov <eugenis@google.com>
Subject: Re: [PATCH 4/6] mm, arm64: untag user addresses in mm/gup.c
Date: Thu, 3 May 2018 18:24:32 +0300 [thread overview]
Message-ID: <20180503152432.q742zvdbv6xtvo34@kshutemo-mobl1> (raw)
In-Reply-To: <CAAeHK+zh0LSpq2VFJeHrV7AETnL1b9R+yex3iPMg5SetbEyxwg@mail.gmail.com>
On Thu, May 03, 2018 at 04:09:56PM +0200, Andrey Konovalov wrote:
> On Wed, May 2, 2018 at 7:25 PM, Andrey Konovalov <andreyknvl@google.com> wrote:
> > On Wed, May 2, 2018 at 5:36 PM, Kirill A. Shutemov
> > <kirill.shutemov@linux.intel.com> wrote:
> >> On Wed, May 02, 2018 at 02:38:42PM +0000, Andrey Konovalov wrote:
> >>> > Does having a tagged address here makes any difference? I couldn't hit a
> >>> > failure with my simple tests (LD_PRELOAD a library that randomly adds
> >>> > tags to pointers returned by malloc).
> >>>
> >>> I think you're right, follow_page_mask is only called from
> >>> __get_user_pages, which already untagged the address. I'll remove
> >>> untagging here.
> >>
> >> It also called from follow_page(). Have you covered all its callers?
> >
> > Oh, missed that, will take a look.
>
> I wasn't able to find anything that calls follow_page with pointers
> passed from userspace except for the memory subsystem syscalls, and we
> deliberately don't add untagging in those.
I guess I missed this part, but could you elaborate on this? Why?
Not yet or not ever?
Also I wounder if we can find (with sparse?) all places where we cast out
__user. This would give a nice list of places where to pay attention.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2018-05-03 15:24 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-18 18:53 [PATCH 0/6] arm64: untag user pointers passed to the kernel Andrey Konovalov
2018-04-18 18:53 ` [PATCH 1/6] arm64: add type casts to untagged_addr macro Andrey Konovalov
2018-04-18 18:53 ` Andrey Konovalov
2018-04-18 18:53 ` [PATCH 2/6] uaccess: add untagged_addr definition for other arches Andrey Konovalov
2018-04-18 18:53 ` Andrey Konovalov
2018-04-18 18:53 ` [PATCH 3/6] arm64: untag user addresses in copy_from_user and others Andrey Konovalov
2018-04-26 15:47 ` Catalin Marinas
2018-05-02 15:29 ` Andrey Konovalov
2018-04-18 18:53 ` Andrey Konovalov
2018-04-18 18:53 ` [PATCH 4/6] mm, arm64: untag user addresses in mm/gup.c Andrey Konovalov
2018-04-26 17:47 ` Catalin Marinas
2018-05-02 14:38 ` Andrey Konovalov
2018-05-02 15:36 ` Kirill A. Shutemov
2018-05-02 17:25 ` Andrey Konovalov
2018-05-03 14:09 ` Andrey Konovalov
2018-05-03 15:24 ` Kirill A. Shutemov [this message]
2018-05-03 16:51 ` Andrey Konovalov
2018-05-08 15:11 ` Catalin Marinas
2018-05-11 12:36 ` Andrey Konovalov
2018-04-18 18:53 ` Andrey Konovalov
2018-04-18 18:53 ` [PATCH 5/6] lib, arm64: untag addrs passed to strncpy_from_user and strnlen_user Andrey Konovalov
2018-04-18 18:53 ` Andrey Konovalov
2018-04-18 18:53 ` [PATCH 6/6] arm64: update Documentation/arm64/tagged-pointers.txt Andrey Konovalov
2018-04-18 18:53 ` Andrey Konovalov
2018-04-19 9:33 ` [PATCH 0/6] arm64: untag user pointers passed to the kernel Kirill A. Shutemov
2018-04-25 14:45 ` Andrey Konovalov
2018-04-26 17:56 ` Catalin Marinas
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