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From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Andrey Konovalov <andreyknvl@google.com>,
	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
Cc: Mark Rutland <mark.rutland@arm.com>,
	Szabolcs Nagy <Szabolcs.Nagy@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Kostya Serebryany <kcc@google.com>,
	Khalid Aziz <khalid.aziz@oracle.com>,
	Felix Kuehling <Felix.Kuehling@amd.com>,
	Jacob Bramley <Jacob.Bramley@arm.com>,
	Leon Romanovsky <leon@kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	Jason Gunthorpe <jgg@ziepe.ca>, Dave Martin <Dave.Martin@arm.com>,
	Evgeniy Stepanov <eugenis@google.com>,
	Kevin Brodsky <kevin.brodsky@arm.com>,
	Kees Cook <keescook@chromium.org>,
	Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
	Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Dmitry Vyukov <dvyukov@google.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Yishai Hadas <yishaih@mellanox.com>,
	Jens Wiklander <jens.wiklander@linaro.org>,
	Lee Smith <Lee.Smith@arm.com>,
	Alexander Deucher <Alexander.Deucher@amd.com>,
	Andrew Morton <akpm@linux-foundation.org>, enh <enh@google.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Christian Koenig <Christian.Koenig@amd.com>,
	Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Subject: Re: [PATCH v17 02/15] lib, arm64: untag user pointers in strn*_user
Date: Wed, 12 Jun 2019 15:28:15 +0100
Message-ID: <0bbc5f4f-9812-463c-48c1-4929bef801da@arm.com> (raw)
In-Reply-To: <a76c014f9b12a082d31ef1459907cabdab78491e.1560339705.git.andreyknvl@google.com>

On 12/06/2019 12:43, 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.
> 
> strncpy_from_user and strnlen_user accept user addresses as arguments, and
> do not go through the same path as copy_from_user and others, so here we
> need to handle the case of tagged user addresses separately.
> 
> Untag user pointers passed to these functions.
> 
> Note, that this patch only temporarily untags the pointers to perform
> validity checks, but then uses them as is to perform user memory accesses.
> 
> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
> Acked-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  lib/strncpy_from_user.c | 3 ++-
>  lib/strnlen_user.c      | 3 ++-
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
> index 023ba9f3b99f..dccb95af6003 100644
> --- a/lib/strncpy_from_user.c
> +++ b/lib/strncpy_from_user.c
> @@ -6,6 +6,7 @@
>  #include <linux/uaccess.h>
>  #include <linux/kernel.h>
>  #include <linux/errno.h>
> +#include <linux/mm.h>
>  
>  #include <asm/byteorder.h>
>  #include <asm/word-at-a-time.h>
> @@ -108,7 +109,7 @@ long strncpy_from_user(char *dst, const char __user *src, long count)
>  		return 0;
>  
>  	max_addr = user_addr_max();
> -	src_addr = (unsigned long)src;
> +	src_addr = (unsigned long)untagged_addr(src);
>  	if (likely(src_addr < max_addr)) {
>  		unsigned long max = max_addr - src_addr;
>  		long retval;
> diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c
> index 7f2db3fe311f..28ff554a1be8 100644
> --- a/lib/strnlen_user.c
> +++ b/lib/strnlen_user.c
> @@ -2,6 +2,7 @@
>  #include <linux/kernel.h>
>  #include <linux/export.h>
>  #include <linux/uaccess.h>
> +#include <linux/mm.h>
>  
>  #include <asm/word-at-a-time.h>
>  
> @@ -109,7 +110,7 @@ long strnlen_user(const char __user *str, long count)
>  		return 0;
>  
>  	max_addr = user_addr_max();
> -	src_addr = (unsigned long)str;
> +	src_addr = (unsigned long)untagged_addr(str);
>  	if (likely(src_addr < max_addr)) {
>  		unsigned long max = max_addr - src_addr;
>  		long retval;
> 

-- 
Regards,
Vincenzo

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Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov
2019-06-12 14:26   ` Vincenzo Frascino
2019-06-12 11:43 ` [PATCH v17 02/15] lib, arm64: untag user pointers in strn*_user Andrey Konovalov
2019-06-12 14:28   ` Vincenzo Frascino [this message]
2019-06-12 11:43 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
2019-06-12 14:30   ` Vincenzo Frascino
2019-06-12 14:55   ` Catalin Marinas
2019-06-13 11:02   ` Dave Martin
2019-06-13 15:26     ` Catalin Marinas
2019-06-14  5:13       ` Kees Cook
2019-06-18  9:18         ` Dave Martin
2019-06-13 11:16   ` Dave Martin
2019-06-13 15:35     ` Catalin Marinas
2019-06-13 15:45       ` Vincenzo Frascino
2019-06-13 15:57         ` Catalin Marinas
2019-06-13 16:15           ` Vincenzo Frascino
2019-06-17 13:56   ` Catalin Marinas
2019-06-17 16:56     ` Szabolcs Nagy
2019-06-17 16:57     ` Evgenii Stepanov
2019-06-17 17:18       ` Catalin Marinas
2019-06-17 21:59         ` Evgenii Stepanov
2019-06-19 14:45   ` Andrey Konovalov
2019-06-19 15:29     ` Catalin Marinas
2019-06-12 11:43 ` [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls Andrey Konovalov
2019-06-12 14:31   ` Vincenzo Frascino
2019-06-19 15:55   ` Khalid Aziz
2019-06-19 16:46     ` Khalid Aziz
2019-06-24 14:22       ` Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 05/15] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov
2019-06-12 14:33   ` Vincenzo Frascino
2019-06-19 16:41   ` Khalid Aziz
2019-06-12 11:43 ` [PATCH v17 06/15] mm, arm64: untag user pointers in get_vaddr_frames Andrey Konovalov
2019-06-12 14:34   ` Vincenzo Frascino
2019-06-19 16:48   ` Khalid Aziz
2019-06-12 11:43 ` [PATCH v17 07/15] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov
2019-06-12 14:35   ` Vincenzo Frascino
2019-06-19 20:01   ` Khalid Aziz
2019-06-12 11:43 ` [PATCH v17 08/15] userfaultfd, arm64: untag user pointers Andrey Konovalov
2019-06-12 14:40   ` Vincenzo Frascino
2019-06-12 11:43 ` [PATCH v17 09/15] drm/amdgpu, " Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 10/15] drm/radeon, arm64: untag user pointers in radeon_gem_userptr_ioctl Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 11/15] IB/mlx4, arm64: untag user pointers in mlx4_get_umem_mr Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 12/15] media/v4l2-core, arm64: untag user pointers in videobuf_dma_contig_user_get Andrey Konovalov
2019-06-19 20:05   ` Khalid Aziz
2019-06-12 11:43 ` [PATCH v17 13/15] tee/shm, arm64: untag user pointers in tee_shm_register Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn Andrey Konovalov
2019-06-12 14:41   ` Vincenzo Frascino
2019-06-12 15:58   ` Auger Eric
2019-06-12 11:43 ` [PATCH v17 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
2019-06-12 12:30   ` Szabolcs Nagy
2019-06-12 15:00     ` Catalin Marinas
2019-06-19 14:42       ` Andrey Konovalov
2019-06-12 14:21 ` [PATCH v4 0/2] arm64 relaxed ABI Vincenzo Frascino
2019-06-12 14:21   ` [PATCH v4 1/2] arm64: Define Documentation/arm64/tagged-address-abi.txt Vincenzo Frascino
2019-06-12 15:35     ` Catalin Marinas
2019-06-13 10:15       ` Vincenzo Frascino
2019-06-13 11:37         ` Dave Martin
2019-06-13 12:28           ` Catalin Marinas
2019-06-13 13:23             ` Dave Martin
2019-06-13 15:39               ` Catalin Marinas
2019-06-12 16:30     ` Szabolcs Nagy
2019-06-13  9:20       ` Catalin Marinas
2019-06-13 10:14         ` Szabolcs Nagy
2019-06-13 11:16           ` Vincenzo Frascino
2019-06-13 12:28             ` Szabolcs Nagy
2019-06-13 14:03               ` Vincenzo Frascino
2019-06-13 15:32                 ` Szabolcs Nagy
2019-06-13 15:35                   ` Vincenzo Frascino
2019-06-12 14:21   ` [PATCH v4 2/2] arm64: Relax Documentation/arm64/tagged-pointers.txt Vincenzo Frascino
2019-06-12 15:56     ` Catalin Marinas
2019-06-12 16:37     ` Szabolcs Nagy
2019-06-13 15:51 ` [PATCH v5 0/2] arm64 relaxed ABI Vincenzo Frascino
2019-06-13 15:51   ` [PATCH v5 1/2] arm64: Define Documentation/arm64/tagged-address-abi.txt Vincenzo Frascino
2019-06-18 11:02     ` Szabolcs Nagy
2019-06-18 13:13     ` Kevin Brodsky
2019-06-21 15:16       ` Catalin Marinas
2019-06-13 15:51   ` [PATCH v5 2/2] arm64: Relax Documentation/arm64/tagged-pointers.txt Vincenzo Frascino

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