From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org by pdx-caf-mail.web.codeaurora.org (Dovecot) with LMTP id aDfTFAGfGVtoVQAAmS7hNA ; Thu, 07 Jun 2018 21:09:21 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 382DD605A2; Thu, 7 Jun 2018 21:09:21 +0000 (UTC) Authentication-Results: smtp.codeaurora.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="LKIRZsb/" X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by smtp.codeaurora.org (Postfix) with ESMTP id A695D601D2; Thu, 7 Jun 2018 21:09:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org A695D601D2 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752469AbeFGVJS (ORCPT + 25 others); Thu, 7 Jun 2018 17:09:18 -0400 Received: from mail-pf0-f194.google.com ([209.85.192.194]:33942 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752172AbeFGVJK (ORCPT ); Thu, 7 Jun 2018 17:09:10 -0400 Received: by mail-pf0-f194.google.com with SMTP id a63-v6so5518129pfl.1; Thu, 07 Jun 2018 14:09:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=gfrV7QMiBEcp+oCgt/tkqzayckx4v0NC6uDo26uyLDM=; b=LKIRZsb/ciNZRb2d+XOhFwJhktI3KabxvXAz9jn+oB7sSAPuCElKtKMQYL+33VZMir OPq5esX1DWlDOIon4376fCfx6c8hytbhKRD1/2WipAAkD6Lq/MUTpRDpSbA+hM9zc1dw z9IYeU/CrmOw8g/A1Vuqh8upkBhoo1Bzn9n8p3PggfNxCxbCKS88yRDznINtQcELLHvX 5y4gpIXhjMU4NPF0Q6+6QvOteL4LfUAoGWgnlgV29amInFkPLIj/TxwMhsug4OGaCq60 j2u3Nhvyjrf7DII2991NOtgcbTiJ07H/SZN5RUaGfjvjohMseqjP2K5CYzDwawOmoWQx kn6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=gfrV7QMiBEcp+oCgt/tkqzayckx4v0NC6uDo26uyLDM=; b=tKeaISsVHh31dLIovQtKy9vdl8t0dtB38O5Rv25OCjq04gOOHdaKseDOM9BgPewBT8 Nt/CZC5EGhVn+VEsGBR7X9Ot+oYYaoiBXYUzalqGdKZjSDsxaSnWxLcEszPdOE6cRqhc rVouzlE6j6ACPHoiRx5qucBNHMNeXKicSLa9/5YuTl8o/UVzaQ+m+fOtkQ3waWBC7oxv liBfaTHygoawvjIVf+dhZdI+7EK+doB8IauGZjgPhpOTN8f7Z/LiRAHvOsTH9dCw7OFC ZNOuQ2tG5DbJUf8nRREfQrqkESIShtSfPhqcxHUE7vA5F0E/YLyzVEoBOyy70BdvAtgE qRdg== X-Gm-Message-State: APt69E3KBBt/Lpa/pHqwv6zSvEEDBkKMSvkR+Oo4uTGEG9DszM46Dll7 etcYaOz8/yvG1wO/hViVqBI= X-Google-Smtp-Source: ADUXVKKs9OC/zWLZYg3bwhEGMSqiBkxPmRwaZRjiteuvP13+x6QROo+lY7FzfpE/bK337oiyV/ESVw== X-Received: by 2002:a65:61a7:: with SMTP id i7-v6mr2900781pgv.219.1528405749295; Thu, 07 Jun 2018 14:09:09 -0700 (PDT) Received: from [10.2.101.129] ([208.91.2.2]) by smtp.gmail.com with ESMTPSA id h17-v6sm84929786pfn.80.2018.06.07.14.09.07 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 Jun 2018 14:09:08 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 10.3 \(3273\)) Subject: Re: [PATCH 09/10] mm: Prevent madvise from changing shadow stack From: Nadav Amit In-Reply-To: <20180607143807.3611-10-yu-cheng.yu@intel.com> Date: Thu, 7 Jun 2018 14:09:05 -0700 Cc: Linux Kernel Mailing List , linux-doc@vger.kernel.org, "open list:MEMORY MANAGEMENT" , linux-arch@vger.kernel.org, the arch/x86 maintainers , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , "H.J. Lu" , Vedvyas Shanbhogue , "Ravi V. Shankar" , Dave Hansen , Andy Lutomirski , Jonathan Corbet , Oleg Nesterov , Arnd Bergmann , Mike Kravetz Content-Transfer-Encoding: quoted-printable Message-Id: References: <20180607143807.3611-1-yu-cheng.yu@intel.com> <20180607143807.3611-10-yu-cheng.yu@intel.com> To: Yu-cheng Yu X-Mailer: Apple Mail (2.3273) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Yu-cheng Yu wrote: > Signed-off-by: Yu-cheng Yu > --- > mm/madvise.c | 9 +++++++++ > 1 file changed, 9 insertions(+) >=20 > diff --git a/mm/madvise.c b/mm/madvise.c > index 4d3c922ea1a1..2a6988badd6b 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -839,6 +839,14 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, = size_t, len_in, int, behavior) > if (vma && start > vma->vm_start) > prev =3D vma; >=20 > + /* > + * Don't do anything on shadow stack. > + */ > + if (vma->vm_flags & VM_SHSTK) { > + error =3D -EINVAL; > + goto out_no_plug; > + } > + > blk_start_plug(&plug); > for (;;) { > /* Still start < end. */ What happens if the madvise() revolves multiple VMAs, the first one is = not VM_SHSTK, but the another one is? Shouldn=E2=80=99t the test be done = inside the loop, potentially in madvise_vma() ?