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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 8FAF1C282C3 for ; Thu, 24 Jan 2019 19:49:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E0ED217D7 for ; Thu, 24 Jan 2019 19:49:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548359380; bh=B1rSheM2lvVXY9NKVRga1Uk/gGg5fGNd2sihX8GID7U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JD6AG4rdvtrcRV+axCeaUZrIGix7Os6dHEpG2Xmt81hK1H24Z9PUH9MBVAHkyTlW4 9gUPJ3YECDcSH7fC/07FUJyJ+FwGQcnu7TTVlrdrlWog9B8KPB45Gsa2qXO+yu7vkF FjcDgssgGxB0okKy3X7A3gm55xulnSEqpQAVWwig= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732717AbfAXTlG (ORCPT ); Thu, 24 Jan 2019 14:41:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:41348 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387504AbfAXTlF (ORCPT ); Thu, 24 Jan 2019 14:41:05 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0B4BC218D0; Thu, 24 Jan 2019 19:41:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548358864; bh=B1rSheM2lvVXY9NKVRga1Uk/gGg5fGNd2sihX8GID7U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=acRneOzx88p1TT6vlI/yh4XRUm/vDDf9NlwFBhuuEM6o1sTdkXyByOAktmU95G0at FAzJq4kC55pqH2NV+y8GGipTrbhBgcjEODdAAp/fr34tSHfmSknrWN/td0p9a8oMe5 eiqmKLkz3OYWBgcw8ZVuPFiQCKrTiHoJt3kQSHdo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Lutomirski , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Linus Torvalds , Peter Zijlstra , Rik van Riel , Thomas Gleixner , Yu-cheng Yu , Ingo Molnar , Sasha Levin Subject: [PATCH 4.20 036/127] x86/fault: Dont try to recover from an implicit supervisor access Date: Thu, 24 Jan 2019 20:19:42 +0100 Message-Id: <20190124190213.833792830@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190124190211.984305387@linuxfoundation.org> References: <20190124190211.984305387@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit ebb53e2597e2dc7637ab213df006e99681b6ee25 ] This avoids a situation in which we attempt to apply various fixups that are not intended to handle implicit supervisor accesses from user mode if we screw up in a way that causes this type of fault. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Yu-cheng Yu Link: http://lkml.kernel.org/r/9999f151d72ff352265f3274c5ab3a4105090f49.1542841400.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- arch/x86/mm/fault.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 71d4b9d4d43f..26388576a599 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -639,6 +639,15 @@ no_context(struct pt_regs *regs, unsigned long error_code, unsigned long flags; int sig; + if (user_mode(regs)) { + /* + * This is an implicit supervisor-mode access from user + * mode. Bypass all the kernel-mode recovery code and just + * OOPS. + */ + goto oops; + } + /* Are we prepared to handle this kernel fault? */ if (fixup_exception(regs, X86_TRAP_PF, error_code, address)) { /* @@ -726,6 +735,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, if (IS_ENABLED(CONFIG_EFI)) efi_recover_from_page_fault(address); +oops: /* * Oops. The kernel tried to access some bad page. We'll have to * terminate things with extreme prejudice: -- 2.19.1