From: Catalin Marinas <catalin.marinas@arm.com>
To: Andrey Konovalov <andreyknvl@google.com>,
Will Deacon <will.deacon@arm.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,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Kees Cook <keescook@chromium.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>,
Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCH v19 02/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
Date: Fri, 9 Aug 2019 17:08:00 +0100 [thread overview]
Message-ID: <20190809160800.GC23083@arrakis.emea.arm.com> (raw)
In-Reply-To: <1c05651c53f90d07e98ee4973c2786ccf315db12.1563904656.git.andreyknvl@google.com>
On Tue, Jul 23, 2019 at 07:58:39PM +0200, Andrey Konovalov wrote:
> From: Catalin Marinas <catalin.marinas@arm.com>
>
> It is not desirable to relax the ABI to allow tagged user addresses into
> the kernel indiscriminately. This patch introduces a prctl() interface
> for enabling or disabling the tagged ABI with a global sysctl control
> for preventing applications from enabling the relaxed ABI (meant for
> testing user-space prctl() return error checking without reconfiguring
> the kernel). The ABI properties are inherited by threads of the same
> application and fork()'ed children but cleared on execve(). A Kconfig
> option allows the overall disabling of the relaxed ABI.
>
> The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> MTE-specific settings like imprecise vs precise exceptions.
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Following several discussions on the list and in private, I'm proposing
the update below. I can send it as a patch on top of the current series
since Will has already queued this.
---------------8<-------------------------------------
From 1b3f57ab0c2c51f8b31c19fb34d270e1f3ee57fe Mon Sep 17 00:00:00 2001
From: Catalin Marinas <catalin.marinas@arm.com>
Date: Fri, 9 Aug 2019 15:09:15 +0100
Subject: [PATCH] fixup! arm64: Introduce prctl() options to control the
tagged user addresses ABI
Rename abi.tagged_addr sysctl control to abi.tagged_addr_disabled,
defaulting to 0. Only prevent prctl(PR_TAGGED_ADDR_ENABLE)from being
called when abi.tagged_addr_disabled==1.
Force unused arg* of the new prctl() to 0.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
arch/arm64/kernel/process.c | 17 ++++++++++-------
kernel/sys.c | 4 ++++
2 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 76b7c55026aa..03689c0beb34 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -579,17 +579,22 @@ void arch_setup_new_exec(void)
/*
* Control the relaxed ABI allowing tagged user addresses into the kernel.
*/
-static unsigned int tagged_addr_prctl_allowed = 1;
+static unsigned int tagged_addr_disabled;
long set_tagged_addr_ctrl(unsigned long arg)
{
- if (!tagged_addr_prctl_allowed)
- return -EINVAL;
if (is_compat_task())
return -EINVAL;
if (arg & ~PR_TAGGED_ADDR_ENABLE)
return -EINVAL;
+ /*
+ * Do not allow the enabling of the tagged address ABI if globally
+ * disabled via sysctl abi.tagged_addr_disabled.
+ */
+ if (arg & PR_TAGGED_ADDR_ENABLE && tagged_addr_disabled)
+ return -EINVAL;
+
update_thread_flag(TIF_TAGGED_ADDR, arg & PR_TAGGED_ADDR_ENABLE);
return 0;
@@ -597,8 +602,6 @@ long set_tagged_addr_ctrl(unsigned long arg)
long get_tagged_addr_ctrl(void)
{
- if (!tagged_addr_prctl_allowed)
- return -EINVAL;
if (is_compat_task())
return -EINVAL;
@@ -618,9 +621,9 @@ static int one = 1;
static struct ctl_table tagged_addr_sysctl_table[] = {
{
- .procname = "tagged_addr",
+ .procname = "tagged_addr_disabled",
.mode = 0644,
- .data = &tagged_addr_prctl_allowed,
+ .data = &tagged_addr_disabled,
.maxlen = sizeof(int),
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
diff --git a/kernel/sys.c b/kernel/sys.c
index c6c4d5358bd3..ec48396b4943 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2499,9 +2499,13 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
error = PAC_RESET_KEYS(me, arg2);
break;
case PR_SET_TAGGED_ADDR_CTRL:
+ if (arg3 || arg4 || arg5)
+ return -EINVAL;
error = SET_TAGGED_ADDR_CTRL(arg2);
break;
case PR_GET_TAGGED_ADDR_CTRL:
+ if (arg2 || arg3 || arg4 || arg5)
+ return -EINVAL;
error = GET_TAGGED_ADDR_CTRL();
break;
default:
next prev parent reply other threads:[~2019-08-09 16:08 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-23 17:58 [PATCH v19 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 02/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
2019-07-31 17:05 ` Dave Hansen
2019-08-01 12:38 ` Kevin Brodsky
2019-08-01 16:45 ` Dave Hansen
2019-08-02 10:50 ` Catalin Marinas
2019-08-09 16:08 ` Catalin Marinas [this message]
2019-07-23 17:58 ` [PATCH v19 03/15] lib: untag user pointers in strn*_user Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 04/15] mm: untag user pointers passed to memory syscalls Andrey Konovalov
2019-08-09 16:03 ` Catalin Marinas
2019-07-23 17:58 ` [PATCH v19 05/15] mm: untag user pointers in mm/gup.c Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 06/15] mm: untag user pointers in get_vaddr_frames Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 07/15] fs/namespace: untag user pointers in copy_mount_options Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 08/15] userfaultfd: untag user pointers Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 09/15] drm/amdgpu: " Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 10/15] drm/radeon: untag user pointers in radeon_gem_userptr_ioctl Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 11/15] IB/mlx4: untag user pointers in mlx4_get_umem_mr Andrey Konovalov
2019-07-24 19:25 ` Jason Gunthorpe
2019-07-25 11:17 ` Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 12/15] media/v4l2-core: untag user pointers in videobuf_dma_contig_user_get Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 13/15] tee/shm: untag user pointers in tee_shm_register Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 14/15] vfio/type1: untag user pointers in vaddr_get_pfn Andrey Konovalov
2019-07-23 17:58 ` [PATCH v19 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
2019-07-23 18:03 ` [PATCH v19 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
2019-07-24 14:02 ` Will Deacon
2019-07-24 14:16 ` Andrey Konovalov
2019-07-24 14:20 ` Will Deacon
2019-07-24 17:12 ` Vincenzo Frascino
2019-08-06 17:13 ` Will Deacon
2019-08-07 17:17 ` Andrey Konovalov
2019-08-08 21:12 ` Kees Cook
2019-08-08 22:33 ` Andrew Morton
2019-08-08 23:09 ` Kees Cook
2019-08-09 9:00 ` Catalin Marinas
2019-08-09 9:28 ` Dave Martin
2019-07-25 13:50 ` [PATCH v6 0/2] arm64 relaxed ABI Vincenzo Frascino
2019-07-25 13:50 ` [PATCH v6 1/2] arm64: Define Documentation/arm64/tagged-address-abi.rst Vincenzo Frascino
2019-07-30 10:32 ` Kevin Brodsky
2019-07-30 13:25 ` Vincenzo Frascino
2019-07-30 13:57 ` Kevin Brodsky
2019-07-30 14:24 ` Vincenzo Frascino
2019-07-30 14:48 ` Kevin Brodsky
2019-07-31 16:43 ` Dave Hansen
2019-08-02 10:08 ` Catalin Marinas
2019-07-25 13:50 ` [PATCH v6 2/2] arm64: Relax Documentation/arm64/tagged-pointers.rst Vincenzo Frascino
2019-07-31 16:50 ` [PATCH v19 00/15] arm64: untag user pointers passed to the kernel Dave Hansen
2019-08-01 12:11 ` Kevin Brodsky
2019-08-01 12:48 ` Andrey Konovalov
2019-08-01 15:36 ` Dave Hansen
2019-08-02 10:20 ` Catalin Marinas
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