From patchwork Mon Oct 24 11:31:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 13017506 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 06BCAECAAA1 for ; Mon, 24 Oct 2022 12:14:29 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.429059.679833 (Exim 4.92) (envelope-from ) id 1omwLN-0001lt-41; Mon, 24 Oct 2022 12:14:13 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 429059.679833; Mon, 24 Oct 2022 12:14:13 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1omwLN-0001lm-1N; Mon, 24 Oct 2022 12:14:13 +0000 Received: by outflank-mailman (input) for mailman id 429059; Mon, 24 Oct 2022 12:14:12 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1omwLM-0001lg-2K for xen-devel@lists.xenproject.org; Mon, 24 Oct 2022 12:14:12 +0000 Received: from dfw.source.kernel.org (dfw.source.kernel.org [2604:1380:4641:c500::1]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 5d0263bb-5395-11ed-91b5-6bf2151ebd3b; Mon, 24 Oct 2022 14:14:10 +0200 (CEST) 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 CE1E5612FE; Mon, 24 Oct 2022 12:14:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B814EC433D6; Mon, 24 Oct 2022 12:14:07 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 5d0263bb-5395-11ed-91b5-6bf2151ebd3b DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666613648; bh=q35u9k51iKg4WFnPv2+Jft9j9x8EK3aRtf5Pa+iGBKU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N3lJStRMIfM1xWFYqREc3zv03PcsQNTZREFDYQk+pT9yVx9WozZGOrOlVilhzF22/ Wr5AjCofsHKgneEeFUqozvy/Km3bGtfIXKZH2yz+iNPksyqfK+Wqd9juu4GNyC7bVk kuLnDNBQIeOKtz3FztqY9EbZUVna89qVxZT0rJbA= 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 5.4 189/255] x86/entry: Work around Clang __bdos() bug Date: Mon, 24 Oct 2022 13:31:39 +0200 Message-Id: <20221024113009.238496303@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113002.471093005@linuxfoundation.org> References: <20221024113002.471093005@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 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 65cf405cd975..26b35e75b701 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -759,6 +759,7 @@ 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); @@ -768,7 +769,7 @@ 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))