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 8DEF9C43219 for ; Sun, 9 Oct 2022 20:59:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231316AbiJIU6f (ORCPT ); Sun, 9 Oct 2022 16:58:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231253AbiJIU5X (ORCPT ); Sun, 9 Oct 2022 16:57:23 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 748E932046; Sun, 9 Oct 2022 13:53:48 -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 ams.source.kernel.org (Postfix) with ESMTPS id 149BEB80DC2; Sun, 9 Oct 2022 20:53:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4715CC433D6; Sun, 9 Oct 2022 20:53:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1665348825; bh=Ni3aGGiJlZu9KJ4N6LRidb1HrO9afGdBuz4Hc+sk+7o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CMuA+Bo3/HgV7u8Lfn7SjpUz9dOkvcGMnrCLpQ/CD25thh7k+OaqwfmkAxknvif3Y Tr7IpRt8EsFV4CAlFC2zjh/zgVDVBf/djg8gCpvc97MuZCNPFNlsDyeoLzo7X1o7sf 6uaeHtdp05ndDSJ+X7GEYW2rVf3JAW6LvHQ9CSeHGtGKbw8wCvoBF2GYfRkHp/ch89 O5DjkWElT0GU8apaMNEt+FCzxbOVIm6thv28geQz/Ei99osG9RVb4yW6K886IFiQ5H NRsD/tYuoVXP/8VmkzoyKVcXndRkGM8727DbwiRCCvkG2sQFcqjfOxrBfqR6ZKgQwM qDzkX4DBAVXEQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kees Cook , Juergen Gross , Boris Ostrovsky , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , xen-devel@lists.xenproject.org, Sasha Levin , nathan@kernel.org, ndesaulniers@google.com, llvm@lists.linux.dev Subject: [PATCH AUTOSEL 5.15 13/15] x86/entry: Work around Clang __bdos() bug Date: Sun, 9 Oct 2022 16:53:06 -0400 Message-Id: <20221009205308.1202627-13-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221009205308.1202627-1-sashal@kernel.org> References: <20221009205308.1202627-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 133ef31639df..561aad13412f 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)) -- 2.35.1