From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50958C433EA for ; Tue, 28 Jul 2020 13:23:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3B08B206D7 for ; Tue, 28 Jul 2020 13:23:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730012AbgG1NXb (ORCPT ); Tue, 28 Jul 2020 09:23:31 -0400 Received: from relay.sw.ru ([185.231.240.75]:37472 "EHLO relay3.sw.ru" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729433AbgG1NXb (ORCPT ); Tue, 28 Jul 2020 09:23:31 -0400 Received: from [192.168.15.36] by relay3.sw.ru with esmtp (Exim 4.93) (envelope-from ) id 1k0PYr-0004Hm-NN; Tue, 28 Jul 2020 16:22:30 +0300 Subject: Re: [RFC PATCH 5/5] mm: introduce MADV_DOEXEC To: Anthony Yznaga , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org Cc: mhocko@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org, gerg@linux-m68k.org, christian.brauner@ubuntu.com, peterz@infradead.org, esyr@redhat.com, jgg@ziepe.ca, christian@kellner.me, areber@redhat.com, cyphar@cyphar.com, steven.sistare@oracle.com References: <1595869887-23307-1-git-send-email-anthony.yznaga@oracle.com> <1595869887-23307-6-git-send-email-anthony.yznaga@oracle.com> From: Kirill Tkhai Message-ID: <743a51db-dc27-c49c-9c65-ac164f5283ba@virtuozzo.com> Date: Tue, 28 Jul 2020 16:22:40 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1595869887-23307-6-git-send-email-anthony.yznaga@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 27.07.2020 20:11, Anthony Yznaga wrote: > madvise MADV_DOEXEC preserves a memory range across exec. Initially > only supported for non-executable, non-stack, anonymous memory. > MADV_DONTEXEC reverts the effect of a previous MADV_DOXEXEC call and > undoes the preservation of the range. After a successful exec call, > the behavior of all ranges reverts to MADV_DONTEXEC. > > Signed-off-by: Steve Sistare > Signed-off-by: Anthony Yznaga > --- > include/uapi/asm-generic/mman-common.h | 3 +++ > mm/madvise.c | 25 +++++++++++++++++++++++++ > 2 files changed, 28 insertions(+) > > diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h > index f94f65d429be..7c5f616b28f7 100644 > --- a/include/uapi/asm-generic/mman-common.h > +++ b/include/uapi/asm-generic/mman-common.h > @@ -72,6 +72,9 @@ > #define MADV_COLD 20 /* deactivate these pages */ > #define MADV_PAGEOUT 21 /* reclaim these pages */ > > +#define MADV_DOEXEC 22 /* do inherit across exec */ > +#define MADV_DONTEXEC 23 /* don't inherit across exec */ > + > /* compatibility flags */ > #define MAP_FILE 0 > > diff --git a/mm/madvise.c b/mm/madvise.c > index dd1d43cf026d..b447fa748649 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -103,6 +103,26 @@ static long madvise_behavior(struct vm_area_struct *vma, > case MADV_KEEPONFORK: > new_flags &= ~VM_WIPEONFORK; > break; > + case MADV_DOEXEC: For me MADV_KEEPONEXEC sounds better as it's symmetric to MADV_KEEPONFORK. > + /* > + * MADV_DOEXEC is only supported on private, non-executable, > + * non-stack anonymous memory and if the VM_EXEC_KEEP flag > + * is available. > + */ > + if (!VM_EXEC_KEEP || vma->vm_file || vma->vm_flags & (VM_EXEC|VM_SHARED|VM_STACK)) { > + error = -EINVAL; > + goto out; > + } > + new_flags |= (new_flags & ~VM_MAYEXEC) | VM_EXEC_KEEP; > + break; > + case MADV_DONTEXEC: > + if (!VM_EXEC_KEEP) { > + error = -EINVAL; > + goto out; > + } > + if (new_flags & VM_EXEC_KEEP) > + new_flags |= (new_flags & ~VM_EXEC_KEEP) | VM_MAYEXEC; > + break; > case MADV_DONTDUMP: > new_flags |= VM_DONTDUMP; > break; > @@ -983,6 +1003,8 @@ static int madvise_inject_error(int behavior, > case MADV_SOFT_OFFLINE: > case MADV_HWPOISON: > #endif > + case MADV_DOEXEC: > + case MADV_DONTEXEC: > return true; > > default: > @@ -1037,6 +1059,9 @@ static int madvise_inject_error(int behavior, > * MADV_DONTDUMP - the application wants to prevent pages in the given range > * from being included in its core dump. > * MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump. > + * MADV_DOEXEC - On exec, preserve and duplicate this area in the new process > + * if the new process allows it. > + * MADV_DONTEXEC - Undo the effect of MADV_DOEXEC. > * > * return values: > * zero - success >