Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752689AbdF0LdN (ORCPT ); Tue, 27 Jun 2017 07:33:13 -0400 Received: from mail-pg0-f66.google.com ([74.125.83.66]:32768 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751659AbdF0LdH (ORCPT ); Tue, 27 Jun 2017 07:33:07 -0400 Message-ID: <1498563132.7935.15.camel@gmail.com> Subject: Re: [RFC v4 03/17] x86: key creation with PKEY_DISABLE_EXECUTE disallowed From: Balbir Singh To: Ram Pai , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, dave.hansen@intel.com, hbabu@us.ibm.com, arnd@arndb.de, akpm@linux-foundation.org, corbet@lwn.net, mingo@redhat.com Date: Tue, 27 Jun 2017 21:32:12 +1000 In-Reply-To: <1498558319-32466-4-git-send-email-linuxram@us.ibm.com> References: <1498558319-32466-1-git-send-email-linuxram@us.ibm.com> <1498558319-32466-4-git-send-email-linuxram@us.ibm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1005 Lines: 31 On Tue, 2017-06-27 at 03:11 -0700, Ram Pai wrote: > x86 does not support disabling execute permissions on a pkey. > > Signed-off-by: Ram Pai > --- > arch/x86/kernel/fpu/xstate.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c > index c24ac1e..d582631 100644 > --- a/arch/x86/kernel/fpu/xstate.c > +++ b/arch/x86/kernel/fpu/xstate.c > @@ -900,6 +900,9 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, > if (!boot_cpu_has(X86_FEATURE_OSPKE)) > return -EINVAL; > > + if (init_val & PKEY_DISABLE_EXECUTE) > + return -EINVAL; > + > /* Set the bits we need in PKRU: */ > if (init_val & PKEY_DISABLE_ACCESS) > new_pkru_bits |= PKRU_AD_BIT; I am not an x86 expert. IIUC, execute disable is done via allocating an execute_only_pkey and checking vma_key via AD + vma_flags against VM_EXEC. Your patch looks good to me Acked-by: Balbir Singh Balbir Singh.