From: Andrey Konovalov <andreyknvl@google.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Kees Cook <keescook@chromium.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Shuah Khan <shuah@kernel.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
linux-arch <linux-arch@vger.kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
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>,
Chintan Pandya <cpandya@codeaurora.org>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Dave Martin <Dave.Martin@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Subject: Re: [PATCH v10 00/12] arm64: untag user pointers passed to the kernel
Date: Tue, 26 Feb 2019 18:18:25 +0100 [thread overview]
Message-ID: <CAAeHK+xCi2MxaykYWCz9mwbOzNpjrFcHex7B-VXektNNWBT+Hw@mail.gmail.com> (raw)
In-Reply-To: <2ad5f897-25c0-90cf-f54f-827876873a0a@intel.com>
On Fri, Feb 22, 2019 at 11:55 PM Dave Hansen <dave.hansen@intel.com> wrote:
>
> On 2/22/19 4:53 AM, Andrey Konovalov wrote:
> > The following testing approaches has been taken to find potential issues
> > with user pointer untagging:
> >
> > 1. Static testing (with sparse [3] and separately with a custom static
> > analyzer based on Clang) to track casts of __user pointers to integer
> > types to find places where untagging needs to be done.
>
> First of all, it's really cool that you took this approach. Sounds like
> there was a lot of systematic work to fix up the sites in the existing
> codebase.
>
> But, isn't this a _bit_ fragile going forward? Folks can't just "make
> sparse" to find issues with missing untags.
Yes, this static approach can only be used as a hint to find some
places where untagging is needed, but certainly not all.
> This seems like something
> where we would ideally add an __tagged annotation (or something) to the
> source tree and then have sparse rules that can look for missed untags.
This has been suggested before, search for __untagged here [1].
However there are many places in the kernel where a __user pointer is
casted into unsigned long and passed further. I'm not sure if it's
possible apply a __tagged/__untagged kind of attribute to non-pointer
types, is it?
[1] https://patchwork.kernel.org/patch/10581535/
next prev parent reply other threads:[~2019-02-26 17:18 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-22 12:53 Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 01/12] uaccess: add untagged_addr definition for other arches Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 02/12] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 03/12] lib, arm64: untag user pointers in strn*_user Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 04/12] mm, arm64: untag user pointers passed to memory syscalls Andrey Konovalov
2019-02-22 23:07 ` Dave Hansen
2019-02-26 14:41 ` Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 05/12] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 06/12] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov
2019-02-22 23:03 ` Dave Hansen
2019-02-26 14:35 ` Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 07/12] fs, arm64: untag user pointers in fs/userfaultfd.c Andrey Konovalov
2019-02-22 23:05 ` Dave Hansen
2019-02-26 14:39 ` Andrey Konovalov
2019-03-01 16:59 ` Catalin Marinas
2019-03-01 18:37 ` Dave Hansen
2019-03-05 17:47 ` Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 08/12] net, arm64: untag user pointers in tcp_zerocopy_receive Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 09/12] kernel, arm64: untag user pointers in prctl_set_mm* Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 10/12] tracing, arm64: untag user pointers in seq_print_user_ip Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 11/12] arm64: update Documentation/arm64/tagged-pointers.txt Andrey Konovalov
2019-02-22 12:53 ` [PATCH v10 12/12] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
2019-02-22 15:35 ` [PATCH v10 00/12] arm64: untag user pointers passed to the kernel Szabolcs Nagy
2019-02-22 15:40 ` Andrey Konovalov
2019-02-22 16:10 ` Szabolcs Nagy
2019-02-26 17:00 ` Andrey Konovalov
2019-02-22 22:54 ` Dave Hansen
2019-02-26 17:18 ` Andrey Konovalov [this message]
2019-02-26 17:35 ` Dave Hansen
2019-02-26 23:17 ` Luc Van Oostenryck
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