From: Kees Cook <keescook@chromium.org>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org,
dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org,
linux-media@vger.kernel.org, kvm@vger.kernel.org,
linux-kselftest@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Yishai Hadas <yishaih@mellanox.com>,
Felix Kuehling <Felix.Kuehling@amd.com>,
Alexander Deucher <Alexander.Deucher@amd.com>,
Christian Koenig <Christian.Koenig@amd.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Jens Wiklander <jens.wiklander@linaro.org>,
Alex Williamson <alex.williamson@redhat.com>,
Leon Romanovsky <leon@kernel.org>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Dave Martin <Dave.Martin@arm.com>,
Khalid Aziz <khalid.aziz@oracle.com>, enh <enh@google.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Christoph Hellwig <hch@infradead.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>,
Robin Murphy <robin.murphy@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Subject: Re: [PATCH v16 02/16] arm64: untag user pointers in access_ok and __uaccess_mask_ptr
Date: Fri, 7 Jun 2019 20:51:08 -0700 [thread overview]
Message-ID: <201906072051.3047B3DC56@keescook> (raw)
In-Reply-To: <4327b260fb17c4776a1e3c844f388e4948cfb747.1559580831.git.andreyknvl@google.com>
On Mon, Jun 03, 2019 at 06:55:04PM +0200, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
>
> copy_from_user (and a few other similar functions) are used to copy data
> from user memory into the kernel memory or vice versa. Since a user can
> provided a tagged pointer to one of the syscalls that use copy_from_user,
> we need to correctly handle such pointers.
>
> Do this by untagging user pointers in access_ok and in __uaccess_mask_ptr,
> before performing access validity checks.
>
> Note, that this patch only temporarily untags the pointers to perform the
> checks, but then passes them as is into the kernel internals.
>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> arch/arm64/include/asm/uaccess.h | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
> index e5d5f31c6d36..9164ecb5feca 100644
> --- a/arch/arm64/include/asm/uaccess.h
> +++ b/arch/arm64/include/asm/uaccess.h
> @@ -94,7 +94,7 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si
> return ret;
> }
>
> -#define access_ok(addr, size) __range_ok(addr, size)
> +#define access_ok(addr, size) __range_ok(untagged_addr(addr), size)
> #define user_addr_max get_fs
>
> #define _ASM_EXTABLE(from, to) \
> @@ -226,7 +226,8 @@ static inline void uaccess_enable_not_uao(void)
>
> /*
> * Sanitise a uaccess pointer such that it becomes NULL if above the
> - * current addr_limit.
> + * current addr_limit. In case the pointer is tagged (has the top byte set),
> + * untag the pointer before checking.
> */
> #define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr)
> static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
> @@ -234,10 +235,11 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
> void __user *safe_ptr;
>
> asm volatile(
> - " bics xzr, %1, %2\n"
> + " bics xzr, %3, %2\n"
> " csel %0, %1, xzr, eq\n"
> : "=&r" (safe_ptr)
> - : "r" (ptr), "r" (current_thread_info()->addr_limit)
> + : "r" (ptr), "r" (current_thread_info()->addr_limit),
> + "r" (untagged_addr(ptr))
> : "cc");
>
> csdb();
> --
> 2.22.0.rc1.311.g5d7573a151-goog
>
--
Kees Cook
next prev parent reply other threads:[~2019-06-08 3:51 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-03 16:55 [PATCH v16 00/16] arm64: untag user pointers passed to the kernel Andrey Konovalov
2019-06-03 16:55 ` [PATCH v16 01/16] uaccess: add untagged_addr definition for other arches Andrey Konovalov
2019-06-03 17:02 ` Khalid Aziz
2019-06-03 17:06 ` Andrey Konovalov
2019-06-03 17:24 ` Khalid Aziz
2019-06-03 17:29 ` Christoph Hellwig
2019-06-03 18:17 ` Khalid Aziz
2019-06-04 11:45 ` Andrey Konovalov
2019-06-03 16:55 ` [PATCH v16 02/16] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov
2019-06-08 3:51 ` Kees Cook [this message]
2019-06-10 17:53 ` Catalin Marinas
2019-06-10 18:07 ` Kees Cook
2019-06-10 18:53 ` Catalin Marinas
2019-06-10 20:36 ` Kees Cook
2019-06-11 14:57 ` Catalin Marinas
2019-06-11 17:09 ` Vincenzo Frascino
2019-06-12 9:32 ` Catalin Marinas
2019-06-12 11:52 ` Vincenzo Frascino
2019-06-11 17:09 ` Andrey Konovalov
2019-06-11 17:39 ` Catalin Marinas
2019-06-12 11:03 ` Andrey Konovalov
2019-06-12 11:04 ` Catalin Marinas
2019-06-03 16:55 ` [PATCH v16 03/16] lib, arm64: untag user pointers in strn*_user Andrey Konovalov
2019-06-08 3:48 ` Kees Cook
2019-06-11 20:06 ` Khalid Aziz
2019-06-03 16:55 ` [PATCH v16 04/16] mm: untag user pointers in do_pages_move Andrey Konovalov
2019-06-08 3:49 ` Kees Cook
2019-06-11 20:18 ` Khalid Aziz
2019-06-12 11:08 ` Andrey Konovalov
2019-06-03 16:55 ` [PATCH v16 05/16] arm64: untag user pointers passed to memory syscalls Andrey Konovalov
2019-06-08 3:51 ` Kees Cook
2019-06-10 14:28 ` Catalin Marinas
2019-06-11 15:35 ` Andrey Konovalov
2019-06-11 17:44 ` Catalin Marinas
2019-06-12 11:13 ` Andrey Konovalov
2019-06-03 16:55 ` [PATCH v16 06/16] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov
2019-06-08 3:59 ` Kees Cook
2019-06-03 16:55 ` [PATCH v16 07/16] mm, arm64: untag user pointers in get_vaddr_frames Andrey Konovalov
2019-06-08 4:00 ` Kees Cook
2019-06-10 14:29 ` Catalin Marinas
2019-06-03 16:55 ` [PATCH v16 08/16] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov
2019-06-08 4:02 ` Kees Cook
2019-06-11 14:38 ` Andrey Konovalov
2019-06-12 11:36 ` Andrey Konovalov
2019-06-03 16:55 ` [PATCH v16 09/16] fs, arm64: untag user pointers in fs/userfaultfd.c Andrey Konovalov
2019-06-08 4:03 ` Kees Cook
2019-06-12 10:45 ` Catalin Marinas
2019-06-03 16:55 ` [PATCH v16 10/16] drm/amdgpu, arm64: untag user pointers Andrey Konovalov
2019-06-03 16:55 ` [PATCH v16 11/16] drm/radeon, arm64: untag user pointers in radeon_gem_userptr_ioctl Andrey Konovalov
2019-06-03 16:55 ` [PATCH v16 12/16] IB, arm64: untag user pointers in ib_uverbs_(re)reg_mr() Andrey Konovalov
2019-06-03 17:46 ` Jason Gunthorpe
2019-06-04 12:18 ` Andrey Konovalov
2019-06-04 12:27 ` Jason Gunthorpe
2019-06-04 12:45 ` Andrey Konovalov
2019-06-04 13:02 ` Jason Gunthorpe
2019-06-04 13:09 ` Andrey Konovalov
2019-06-12 11:01 ` Catalin Marinas
2019-06-03 16:55 ` [PATCH v16 13/16] media/v4l2-core, arm64: untag user pointers in videobuf_dma_contig_user_get Andrey Konovalov
2019-06-08 3:52 ` Kees Cook
2019-06-03 16:55 ` [PATCH v16 14/16] tee, arm64: untag user pointers in tee_shm_register Andrey Konovalov
2019-06-07 5:33 ` Jens Wiklander
2019-06-08 4:05 ` Kees Cook
2019-06-03 16:55 ` [PATCH v16 15/16] vfio/type1, arm64: untag user pointers in vaddr_get_pfn Andrey Konovalov
2019-06-08 3:58 ` Kees Cook
2019-06-12 10:38 ` Catalin Marinas
2019-06-03 16:55 ` [PATCH v16 16/16] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
2019-06-08 3:56 ` Kees Cook
2019-06-10 22:08 ` shuah
2019-06-11 15:01 ` Catalin Marinas
2019-06-11 17:18 ` Andrey Konovalov
2019-06-11 17:50 ` Catalin Marinas
2019-06-12 11:14 ` Andrey Konovalov
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