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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50B05FA3745 for ; Mon, 24 Oct 2022 13:26:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231630AbiJXNZy (ORCPT ); Mon, 24 Oct 2022 09:25:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236019AbiJXNYG (ORCPT ); Mon, 24 Oct 2022 09:24:06 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 017818768A; Mon, 24 Oct 2022 05:30:24 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 911BE612F5; Mon, 24 Oct 2022 12:29:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A5BCC433D6; Mon, 24 Oct 2022 12:29:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666614547; bh=aW+O/Bep5E72Knf9F5KLUligbpxqba0bCHR1Uql63Oo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cQtyDm7tvpANV4AlaDyclQKUJhPvkh6ix3TEF/Pmh/UHGFZ0K62W+PbDuPCK1TCwq gLqfRAKygujAdEWgsogkoaxob480dvaiC6ZKlQCPN4bBzOSfbRwq+QAK+cF94ZrYO7 m2rmpZ/eLuonEkxUyNpu0DUjvi4+ZyEHPwupMz3w= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Juergen Gross , Boris Ostrovsky , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , xen-devel@lists.xenproject.org, Kees Cook , Sasha Levin Subject: [PATCH 5.10 302/390] x86/entry: Work around Clang __bdos() bug Date: Mon, 24 Oct 2022 13:31:39 +0200 Message-Id: <20221024113035.871644092@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113022.510008560@linuxfoundation.org> References: <20221024113022.510008560@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Kees Cook [ Upstream commit 3e1730842f142add55dc658929221521a9ea62b6 ] Clang produces a false positive when building with CONFIG_FORTIFY_SOURCE=y and CONFIG_UBSAN_BOUNDS=y when operating on an array with a dynamic offset. Work around this by using a direct assignment of an empty instance. Avoids this warning: ../include/linux/fortify-string.h:309:4: warning: call to __write_overflow_field declared with 'warn ing' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wat tribute-warning] __write_overflow_field(p_size_field, size); ^ which was isolated to the memset() call in xen_load_idt(). Note that this looks very much like another bug that was worked around: https://github.com/ClangBuiltLinux/linux/issues/1592 Cc: Juergen Gross Cc: Boris Ostrovsky Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: x86@kernel.org Cc: "H. Peter Anvin" Cc: xen-devel@lists.xenproject.org Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/lkml/41527d69-e8ab-3f86-ff37-6b298c01d5bc@oracle.com Signed-off-by: Kees Cook Signed-off-by: Sasha Levin --- arch/x86/xen/enlighten_pv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index 804c65d2b95f..815030b7f6fa 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -768,6 +768,7 @@ static void xen_load_idt(const struct desc_ptr *desc) { static DEFINE_SPINLOCK(lock); static struct trap_info traps[257]; + static const struct trap_info zero = { }; unsigned out; trace_xen_cpu_load_idt(desc); @@ -777,7 +778,7 @@ static void xen_load_idt(const struct desc_ptr *desc) memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc)); out = xen_convert_trap_info(desc, traps, false); - memset(&traps[out], 0, sizeof(traps[0])); + traps[out] = zero; xen_mc_flush(); if (HYPERVISOR_set_trap_table(traps)) -- 2.35.1