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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 46CB2C2B9F4 for ; Mon, 14 Jun 2021 16:38:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3230361078 for ; Mon, 14 Jun 2021 16:38:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234912AbhFNQk3 (ORCPT ); Mon, 14 Jun 2021 12:40:29 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:55848 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234793AbhFNQkA (ORCPT ); Mon, 14 Jun 2021 12:40:00 -0400 Message-Id: <20210614155354.630211386@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1623688676; 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=vIGJlj6yAQUQhqtDz0ifh1jGuBG8HIiu+//WZQJJHaU=; b=lPzInPasKXtYjGW1tp/8kcfJymluNouQSBz02B91nbdbniL1KC2/W/L+WelFznGbAZZT7c utsCp9frmx/8DR7qSuJA+Yayc2rbCemOaN7DBK0EN3NrPdLpJzbS0XXmmC6SVZspz+wwaJ NGLzmMlUH6Q0SdKgMwIVKgBIHFcs8DcAifyN8nrx+grQ3bHcYXThJaVjkxwXL3bzElSO06 6JMl8//ekmrxWjktkynbxB1nDF40zQym7kyNIqg5xAmykwX6k6/KE8/CIWhcrJlL/23M+t iRmIKv7nLax8mVyIOb8gMCu9avgirU+PTomHnLqYa+n7MrGlaS6QGyYQaBrHpg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1623688676; 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=vIGJlj6yAQUQhqtDz0ifh1jGuBG8HIiu+//WZQJJHaU=; b=ECUaBiD3MLFxWrgyO9G3z7OQ/aPKB7p+V5pkOJSwv8WkaZxFtYR2tfnn4KdWLoD+5WRB0I ptlwgBDo15hVqmCw== Date: Mon, 14 Jun 2021 17:44:17 +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 Subject: [patch V2 09/52] x86/fpu: Reject invalid MXCSR values in copy_kernel_to_xstate() References: <20210614154408.673478623@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 Instead of masking out reserved bits, check them and reject the provided state as invalid if not zero. Suggested-by: Andy Lutomirski Signed-off-by: Thomas Gleixner --- V2: New patch --- arch/x86/kernel/fpu/xstate.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1166,6 +1166,14 @@ int copy_kernel_to_xstate(struct xregs_s if (validate_user_xstate_header(&hdr)) return -EINVAL; + if (xfeatures_mxcsr_quirk(hdr.xfeatures)) { + const u32 *mxcsr = kbuf + offsetof(struct fxregs_state, mxcsr); + + /* Reserved bits in MXCSR must be zero. */ + if (*mxcsr & ~mxcsr_feature_mask) + return -EINVAL; + } + for (i = 0; i < XFEATURE_MAX; i++) { u64 mask = ((u64)1 << i); @@ -1196,9 +1204,6 @@ int copy_kernel_to_xstate(struct xregs_s */ xsave->header.xfeatures |= hdr.xfeatures; - /* mxcsr reserved bits must be masked to zero for historical reasons. */ - xsave->i387.mxcsr &= mxcsr_feature_mask; - return 0; }