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=-8.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 9CB4EC2D0E2 for ; Tue, 22 Sep 2020 19:40:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 56D32238A1 for ; Tue, 22 Sep 2020 19:40:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="QF/L4AUz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726576AbgIVTkp (ORCPT ); Tue, 22 Sep 2020 15:40:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57370 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726448AbgIVTko (ORCPT ); Tue, 22 Sep 2020 15:40:44 -0400 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5332C0613D0 for ; Tue, 22 Sep 2020 12:40:44 -0700 (PDT) Received: by mail-pg1-x544.google.com with SMTP id d13so12817186pgl.6 for ; Tue, 22 Sep 2020 12:40:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=2BLOzorBaeMlVA6pN2kcbxJVGruVZzdD42GOXHQAwXs=; b=QF/L4AUzghb8cbfbsn5C54l9EjVtyQlMBHw5DBOgg702StUFumc+dQnYDzxOVBLvXW M4U1Mc3JjnACeI3kX2ghKWxBYt8Uq94PfCZm39zZ98KItafpCVjviJoAeCBOG3IFdh9A X2N5hMxWBBIjm9bwj8dz5X7orXiGp8WJZDqrQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=2BLOzorBaeMlVA6pN2kcbxJVGruVZzdD42GOXHQAwXs=; b=mC1iZC/tsmldtnx5wO0igvjFCVXKRRlYawC/0lPfRX+M1u6LJNkI+ggf9mfQlOGGwT 6mkX3BjyCU7Isn5N8/EH+I2x53mhObBni0Zytelqrb9eiPy5mA1EG50/Tb9Chvt/DEpi 2Vtw/Gp4qQshcTeJP8Ds7fYL6y/ztOaqwEFdUFltyVF3cMIrEwiLBifZQaEAc8dP0BiN JkvA5FUL9DTgPGB5kw2gyrxaIGnCp/20c0ieNb1Qn0MR8ZJDJewxTnJ+OoetY85ucRq3 B9NIb/SX1B5jZQ7qyOBZjPbDUfauZ4S9cCFKWha+g75jeIy8658AQTkEeZL/Or57JI6d NPbQ== X-Gm-Message-State: AOAM532/N211rR1KJ75W1ee5MtX/l+FWFQ7iuaUpK1GkHj8hhHkgPSDT JEuPFIHTwcLJ0iA96qPbUfCUGA== X-Google-Smtp-Source: ABdhPJwvYT+NFhGms3dCbMaV9tf8Dw4PMzNnCfSDO3kcJYCAgiqqgfJQsGvvKNmk9TA+xIVl2/U5ug== X-Received: by 2002:a63:c20b:: with SMTP id b11mr1483828pgd.421.1600803644339; Tue, 22 Sep 2020 12:40:44 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id m5sm3003272pjn.19.2020.09.22.12.40.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Sep 2020 12:40:43 -0700 (PDT) Date: Tue, 22 Sep 2020 12:40:42 -0700 From: Kees Cook To: Gabriel Krisman Bertazi Cc: luto@kernel.org, tglx@linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, willy@infradead.org, linux-kselftest@vger.kernel.org, shuah@kernel.org, kernel@collabora.com Subject: Re: [PATCH v6 3/9] x86: vdso: Expose sigreturn address on vdso to the kernel Message-ID: <202009221240.D7B051D3@keescook> References: <20200904203147.2908430-1-krisman@collabora.com> <20200904203147.2908430-4-krisman@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200904203147.2908430-4-krisman@collabora.com> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Fri, Sep 04, 2020 at 04:31:41PM -0400, Gabriel Krisman Bertazi wrote: > Syscall user redirection requires the signal trampoline code to not be > captured, in order to support returning with a locked selector while > avoiding recursion back into the signal handler. For ia-32, which has > the trampoline in the vDSO, expose the entry points to the kernel, such > that it can avoid dispatching syscalls from that region to userspace. > > Changes since V1 > - Change return address to bool (Andy) > > Suggested-by: Andy Lutomirski > Acked-by: Andy Lutomirski > Signed-off-by: Gabriel Krisman Bertazi Look good to me; would anything else benefit from this information? Reviewed-by: Kees Cook -- Kees Cook