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 781E1C2B9F4 for ; Sat, 19 Jun 2021 08:35:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5674361222 for ; Sat, 19 Jun 2021 08:35:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234292AbhFSIhP (ORCPT ); Sat, 19 Jun 2021 04:37:15 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:58582 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234202AbhFSIhO (ORCPT ); Sat, 19 Jun 2021 04:37:14 -0400 Received: from imap.suse.de (imap-alt.suse-dmz.suse.de [192.168.254.47]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 7B1951FD2D; Sat, 19 Jun 2021 08:35:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1624091703; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=q+MjFqL+kLBlA8ILICgJ1s2xiR+V4tpKyupBnPQjWVI=; b=2TPmR165IiCFkKmw8g+5DX17lW1HU9W4RL4keeI328TBsuTDRPJCov8UYldh71mXEpGvYF ng87vt+V4KJEgc0c09Vif8J4ygrDLfTEtSDVNdI7R5CPjbTArvmU0+DbLx2DmKz/H1G2/7 zh2ed8uzS+ohClI5g9uhVLDM+eT1HkA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1624091703; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=q+MjFqL+kLBlA8ILICgJ1s2xiR+V4tpKyupBnPQjWVI=; b=QSB6bRJm0LvxXyhXcqNKvKdCXMP3VT/G+tdmMWBD2HqW46OYLa58kDzaUacdrg0SYzV6MM 0PdVbR7h+n8067BQ== Received: from imap3-int (imap-alt.suse-dmz.suse.de [192.168.254.47]) by imap.suse.de (Postfix) with ESMTP id 62DA1118DD; Sat, 19 Jun 2021 08:35:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1624091703; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=q+MjFqL+kLBlA8ILICgJ1s2xiR+V4tpKyupBnPQjWVI=; b=2TPmR165IiCFkKmw8g+5DX17lW1HU9W4RL4keeI328TBsuTDRPJCov8UYldh71mXEpGvYF ng87vt+V4KJEgc0c09Vif8J4ygrDLfTEtSDVNdI7R5CPjbTArvmU0+DbLx2DmKz/H1G2/7 zh2ed8uzS+ohClI5g9uhVLDM+eT1HkA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1624091703; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=q+MjFqL+kLBlA8ILICgJ1s2xiR+V4tpKyupBnPQjWVI=; b=QSB6bRJm0LvxXyhXcqNKvKdCXMP3VT/G+tdmMWBD2HqW46OYLa58kDzaUacdrg0SYzV6MM 0PdVbR7h+n8067BQ== Received: from director2.suse.de ([192.168.254.72]) by imap3-int with ESMTPSA id OyGBFzeszWBkQAAALh3uQQ (envelope-from ); Sat, 19 Jun 2021 08:35:03 +0000 Date: Sat, 19 Jun 2021 10:34:53 +0200 From: Borislav Petkov To: Thomas Gleixner Cc: LKML , Andy Lutomirski , Dave Hansen , Fenghua Yu , Tony Luck , Yu-cheng Yu , Sebastian Andrzej Siewior , Peter Zijlstra , Kan Liang Subject: Re: [patch V3 01/66] x86/fpu: x86/fpu: Preserve supervisor states in sanitize_restored_user_xstate() Message-ID: References: <20210618141823.161158090@linutronix.de> <20210618143444.438635017@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210618143444.438635017@linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 18, 2021 at 04:18:24PM +0200, Thomas Gleixner wrote: > Subject: Re: [patch V3 01/66] x86/fpu: x86/fpu: Preserve supervisor states in Prefix repeated. > From: Thomas Gleixner > > sanitize_restored_user_xstate() preserves the supervisor states only > when the fx_only argument is zero, which allows unpriviledged user space > to put supervisor states back into init state. Yikes. > Preserve them unconditionally. > > Fixes: 5d6b6a6f9b5c ("x86/fpu/xstate: Update sanitize_restored_xstate() for supervisor xstates") > Signed-off-by: Thomas Gleixner > Cc: stable@vger.kernel.org > --- > arch/x86/kernel/fpu/signal.c | 26 ++++++++------------------ > 1 file changed, 8 insertions(+), 18 deletions(-) > > --- a/arch/x86/kernel/fpu/signal.c > +++ b/arch/x86/kernel/fpu/signal.c > @@ -221,28 +221,18 @@ sanitize_restored_user_xstate(union fpre > > if (use_xsave()) { > /* > - * Note: we don't need to zero the reserved bits in the > - * xstate_header here because we either didn't copy them at all, > - * or we checked earlier that they aren't set. > + * Clear all features bit which are not set in feature bits > + * user_xfeatures and clear all extended features > + * for fx_only mode. > */ > + u64 mask = fx_only ? XFEATURE_MASK_FPSSE : user_xfeatures; > > /* > - * 'user_xfeatures' might have bits clear which are > - * set in header->xfeatures. This represents features that > - * were in init state prior to a signal delivery, and need > - * to be reset back to the init state. Clear any user > - * feature bits which are set in the kernel buffer to get > - * them back to the init state. > - * > - * Supervisor state is unchanged by input from userspace. > - * Ensure supervisor state bits stay set and supervisor > - * state is not modified. > + * Supervisor state has to be preserved. The sigframe > + * restore can only modify user features, i.e. @mask > + * cannot contain them. > */ > - if (fx_only) > - header->xfeatures = XFEATURE_MASK_FPSSE; > - else > - header->xfeatures &= user_xfeatures | > - xfeatures_mask_supervisor(); > + header->xfeatures &= mask | xfeatures_mask_supervisor(); With those addressed: Reviewed-by: Borislav Petkov Thx. -- Regards/Gruss, Boris. SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg