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,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 94408C54FD0 for ; Tue, 21 Apr 2020 15:16:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 648AC20724 for ; Tue, 21 Apr 2020 15:16:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587482164; bh=YVIscHMOrTaQHoHxqIyKIGGcJUXzpYR5yik6aJPF/Cg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IAOpOM0WcSnnp1ThQkuiQnUXjzmoYYUMktv468YjdbvJ/H5kA+Kx5aKsztFwWigPI RtIDH4AtjR0+eWb0Spk7b08WzuQ4LughpLSJDtU+KyCO+ypCGBYjb811j5HpkHOOGZ e9U92Ip8RjtU191ymFeBKwa0egg3p7PuPzmggiL0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727928AbgDUPQD (ORCPT ); Tue, 21 Apr 2020 11:16:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:34892 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726946AbgDUPQB (ORCPT ); Tue, 21 Apr 2020 11:16:01 -0400 Received: from localhost.localdomain (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9071C2070B; Tue, 21 Apr 2020 15:15:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587482160; bh=YVIscHMOrTaQHoHxqIyKIGGcJUXzpYR5yik6aJPF/Cg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E3FVW4+BW1V++0qO9DOErMnVGSt3t0xhN1WWDXKeeTzYQIIgbKQaQrT+RcFp89mdK JKpqrEtr6r/9FHjgPmvqfNy3tLdIvUaY/ICxW+VNSsBcRtIR0TpptndtMekxDVOhID SW0N+JBf2l/QIKf7X85xEdakm/5UdbmoRQ9zw4mE= From: Will Deacon To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, kernel-team@android.com, Will Deacon , Mark Rutland , Michael Ellerman , Peter Zijlstra , Linus Torvalds , Segher Boessenkool , Christian Borntraeger , Luc Van Oostenryck , Arnd Bergmann , Peter Oberparleiter , Masahiro Yamada , Nick Desaulniers , Robin Murphy Subject: [PATCH v4 05/11] arm64: csum: Disable KASAN for do_csum() Date: Tue, 21 Apr 2020 16:15:31 +0100 Message-Id: <20200421151537.19241-6-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200421151537.19241-1-will@kernel.org> References: <20200421151537.19241-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org do_csum() over-reads the source buffer and therefore abuses READ_ONCE_NOCHECK() to avoid tripping up KASAN. In preparation for READ_ONCE_NOCHECK() becoming a macro, and therefore losing its '__no_sanitize_address' annotation, just annotate do_csum() explicitly and fall back to normal loads. Cc: Mark Rutland Cc: Robin Murphy Signed-off-by: Will Deacon --- arch/arm64/lib/csum.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/arch/arm64/lib/csum.c b/arch/arm64/lib/csum.c index 60eccae2abad..78b87a64ca0a 100644 --- a/arch/arm64/lib/csum.c +++ b/arch/arm64/lib/csum.c @@ -14,7 +14,11 @@ static u64 accumulate(u64 sum, u64 data) return tmp + (tmp >> 64); } -unsigned int do_csum(const unsigned char *buff, int len) +/* + * We over-read the buffer and this makes KASAN unhappy. Instead, disable + * instrumentation and call kasan explicitly. + */ +unsigned int __no_sanitize_address do_csum(const unsigned char *buff, int len) { unsigned int offset, shift, sum; const u64 *ptr; @@ -42,7 +46,7 @@ unsigned int do_csum(const unsigned char *buff, int len) * odd/even alignment, and means we can ignore it until the very end. */ shift = offset * 8; - data = READ_ONCE_NOCHECK(*ptr++); + data = *ptr++; #ifdef __LITTLE_ENDIAN data = (data >> shift) << shift; #else @@ -58,10 +62,10 @@ unsigned int do_csum(const unsigned char *buff, int len) while (unlikely(len > 64)) { __uint128_t tmp1, tmp2, tmp3, tmp4; - tmp1 = READ_ONCE_NOCHECK(*(__uint128_t *)ptr); - tmp2 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 2)); - tmp3 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 4)); - tmp4 = READ_ONCE_NOCHECK(*(__uint128_t *)(ptr + 6)); + tmp1 = *(__uint128_t *)ptr; + tmp2 = *(__uint128_t *)(ptr + 2); + tmp3 = *(__uint128_t *)(ptr + 4); + tmp4 = *(__uint128_t *)(ptr + 6); len -= 64; ptr += 8; @@ -85,7 +89,7 @@ unsigned int do_csum(const unsigned char *buff, int len) __uint128_t tmp; sum64 = accumulate(sum64, data); - tmp = READ_ONCE_NOCHECK(*(__uint128_t *)ptr); + tmp = *(__uint128_t *)ptr; len -= 16; ptr += 2; @@ -100,7 +104,7 @@ unsigned int do_csum(const unsigned char *buff, int len) } if (len > 0) { sum64 = accumulate(sum64, data); - data = READ_ONCE_NOCHECK(*ptr); + data = *ptr; len -= 8; } /* -- 2.26.1.301.g55bc3eb7cb9-goog