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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 0F5F7C48BC2 for ; Wed, 23 Jun 2021 12:24:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC8376100B for ; Wed, 23 Jun 2021 12:24:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230513AbhFWM01 (ORCPT ); Wed, 23 Jun 2021 08:26:27 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:36454 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230452AbhFWM0J (ORCPT ); Wed, 23 Jun 2021 08:26:09 -0400 Message-Id: <20210623121452.613614842@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1624451031; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=sdKtzcqxryqLfTc5w3untPCPdvNPe8f8Qf8dZKG7LWA=; b=2np6/M5J8K61L9xc2AvjXpSq+W3fVn/v1XfQlbcWRU87RFX/mIr5AnBmMnOvj2t3Cz5r3V pW3zZYlUeKWmrlTZwrNr3KAtbbap7nMoNcvsXjLDVQMCmQGeE5qBr+In1OD4jIEIar/f68 xiWtIppNIXNR+wnLJUph1Y4LThdyxxZp0RaAS7AasAl2aOHCGQnMShYNY+w7D5H5sUButy RL61ikGPrrylN1Eybcat8aRomfWLcfMB+PO4b5KGihtw36CKAaWNOEZdho+ZYk4PTokoxm GOTREoIY1RkbUj5OFCuyWhomaYIu1D4AmoSDbEml9UmSSZSsJUtu78HOsvhyMw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1624451031; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=sdKtzcqxryqLfTc5w3untPCPdvNPe8f8Qf8dZKG7LWA=; b=qp4DGj5aGeS4SZBpuyhzqTcVRYx+RCa79dX4euay0NMhbMy2hdj2f7iI0qOO184UXTSyZi OVD92pD986w8+/DA== Date: Wed, 23 Jun 2021 14:01:40 +0200 From: Thomas Gleixner To: LKML Cc: Andy Lutomirski , Dave Hansen , Fenghua Yu , Tony Luck , Yu-cheng Yu , Sebastian Andrzej Siewior , Borislav Petkov , Peter Zijlstra , Kan Liang , "Chang Seok Bae" , Megha Dey , Oliver Sang Subject: [patch V4 13/65] x86/fpu: Fail ptrace() requests that try to set invalid MXCSR values References: <20210623120127.327154589@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-transfer-encoding: 8-bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andy Lutomirski There is no benefit from accepting and silently changing an invalid MXCSR value supplied via ptrace(). Instead, return -EINVAL on invalid input. Signed-off-by: Andy Lutomirski Signed-off-by: Thomas Gleixner --- V2: New patch. Picked up from Andy. --- arch/x86/kernel/fpu/regset.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -64,8 +64,9 @@ int xfpregs_set(struct task_struct *targ if (ret) return ret; - /* Mask invalid MXCSR bits (for historical reasons). */ - newstate.mxcsr &= mxcsr_feature_mask; + /* Do not allow an invalid MXCSR value. */ + if (newstate.mxcsr & ~mxcsr_feature_mask) + return -EINVAL; fpu__prepare_write(fpu);