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=-5.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A8CE0C43603 for ; Wed, 11 Dec 2019 17:37:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8222B20637 for ; Wed, 11 Dec 2019 17:37:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="j3MRlnLT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729942AbfLKRhO (ORCPT ); Wed, 11 Dec 2019 12:37:14 -0500 Received: from mail.skyhub.de ([5.9.137.197]:56382 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727334AbfLKRhO (ORCPT ); Wed, 11 Dec 2019 12:37:14 -0500 Received: from zn.tnic (p200300EC2F094900329C23FFFEA6A903.dip0.t-ipconnect.de [IPv6:2003:ec:2f09:4900:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 17A371EC0591; Wed, 11 Dec 2019 18:37:13 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1576085833; 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:in-reply-to:in-reply-to: references:references; bh=/fQSVH4e2kOh1ufr5QULeFyUccGwjWVFvNcXOqos5bc=; b=j3MRlnLTHkMRuZ7QpudWgF6/T2UqokFtYoPNG1Yr0vcl1cqrwaFFEOLLDsNTjKXHlPyDjl /jMUop/434oLwmjhI+9f8A5KEov4WxhHidW2RpmlC1NnHXoHJ+iN8wMXGjCRkXFIIgHyfG Y80o5U8gGTn+LK4dKb3lkvYKayZF+7E= Date: Wed, 11 Dec 2019 18:37:12 +0100 From: Borislav Petkov To: Jann Horn Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, Andrey Konovalov , Andy Lutomirski , Sean Christopherson Subject: Re: [PATCH v6 4/4] x86/kasan: Print original address on #GP Message-ID: <20191211173711.GF14821@zn.tnic> References: <20191209143120.60100-1-jannh@google.com> <20191209143120.60100-4-jannh@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191209143120.60100-4-jannh@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 09, 2019 at 03:31:20PM +0100, Jann Horn wrote: > arch/x86/kernel/traps.c | 12 ++++++++++- > arch/x86/mm/kasan_init_64.c | 21 ------------------- > include/linux/kasan.h | 6 ++++++ > mm/kasan/report.c | 40 +++++++++++++++++++++++++++++++++++++ > 4 files changed, 57 insertions(+), 22 deletions(-) I need a KASAN person ACK here, I'd guess. > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c > index c8b4ae6aed5b..7813592b4fb3 100644 > --- a/arch/x86/kernel/traps.c > +++ b/arch/x86/kernel/traps.c > @@ -37,6 +37,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -589,6 +590,8 @@ do_general_protection(struct pt_regs *regs, long error_code) > if (!user_mode(regs)) { > enum kernel_gp_hint hint = GP_NO_HINT; > unsigned long gp_addr; > + unsigned long flags; > + int sig; > > if (fixup_exception(regs, X86_TRAP_GP, error_code, 0)) > return; > @@ -621,7 +624,14 @@ do_general_protection(struct pt_regs *regs, long error_code) > "maybe for address", > gp_addr); > > - die(desc, regs, error_code); > + flags = oops_begin(); > + sig = SIGSEGV; > + __die_header(desc, regs, error_code); > + if (hint == GP_NON_CANONICAL) > + kasan_non_canonical_hook(gp_addr); > + if (__die_body(desc, regs, error_code)) > + sig = 0; > + oops_end(flags, regs, sig); Instead of opencoding it like this, can we add a die_addr(desc, regs, error_code, gp_addr); to arch/x86/kernel/dumpstack.c and call it from here: if (hint != GP_NON_CANONICAL) gp_addr = 0; die_addr(desc, regs, error_code, gp_addr); This way you won't need to pass down to die_addr() the hint too - you code into gp_addr whether it was non-canonical or not. The + if (addr < KASAN_SHADOW_OFFSET) + return; check in kasan_non_canonical_hook() would then catch it when addr == 0. Hmmm? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette